EFA Botswana Aquatic Macroinvertebrates
Okavango River Basin Technical
Diagnostic Analysis:
Environmental Flow Module
Specialist Report
Country: Botswana
Discipline: Aquatic Macroinvertebrates
Belda Q. Mosepele
Helen Dallas
July 2009
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EFA Botswana Aquatic Macroinvertebrates
Okavango River Basin Technical
Diagnostic Analysis:
Environmental Flow Module
Specialist Report
Country: Botswana
Discipline: Aquatic Macroinvertebrates
Author: Belda Q. Mosepele and Dr. Helen Dallas
Date: July 05th 2009
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EFA Botswana Aquatic Macroinvertebrates
EXECUTIVE SUMMARY
The diagnostic analysis of aquatic macroinvertebrates environmental flows for the Okavango
Delta used existing data on previous research studies conducted for the Okavango Delta for
the past 7 years. Freshwater aquatic macroinvertebrates are very important food for fish and
other organisms. Being at the bottom of the food web, they play a role in energy transfer and
ecosystem recycling. Data was collected in four focal points, which have a mosaic of habitats
that represent the Okavango Delta. A scoop net was used to sample in the marginal
vegetation, floating vegetation, instream vegetation, pools and lagoons from the Upper
Panhandle to the lower delta in Boro, Thamalakane and Boteti rivers. There are
approximately 63 families of macroinvertebrates in the Okavango Delta, some of these
aquatic macroinvertebrates like blackflies can be important vectors of diseases. They are
responsible for transmitting onchocerciasis (river blindness) to millions of people in tropical
areas around the world. Other important aquatic macroinvertebrates found in the Okavango
delta are the ancient like shrimps, and rare crustaceans (fairy shrimp) that occur mostly in
pools in Moremi Game Reserve. In some previous studies, water quality parameters (Ph,
DO, conductivity and temperature) was also collected. The data of previous studies,
unfortunately did collect any information that relates macroinvertebrates distribution and
abundance links to flow and floods, the drivers of the ecosystem, therefore several other
literature from elsewhere was used to give an insight of macroinvertebrates links to flow. In
addition, the EFA study used macroinvertebrates data that was identified only up to the
family level.
Results from EFA study is a selection of key indicator species (families). These indicators
were selected based on their feeding guild, preferred habitat, abundance/occurrence and
distribution in the Delta. Another result is the knowledge captured and the development of
the response curves for each indicator and relate to various development scenarios. The
scenarios indicate that not many families of aquatic macroinvertebrates will have a dramatic
change under any of the three development scenarios, however, from the response curves,
some habitats in the lower Delta - the Boteti river might occur with any development
scenario.
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EFA Botswana Aquatic Macroinvertebrates
TABLE OF CONTENTS
EXECUTIVE SUMMARY ................................................................................................. 3
ABBREVIATIONS ........................................................................................................... 7
ACKNOWLEDGEMENTS ............................................................................................... 7
1.INTRODUCTION .......................................................................................................... 8
1.1Background ................................................................................................................ 8
1.2Okavango River Basin EFA Objectives and Workplan ............................................... 8
1.2.1Project objectives .................................................................................................... 8
2STUDY AREA ............................................................................................................... 9
2.1Description of the Okavango Basin ............................................................................ 9
2.2Delineation of the Okavango Basin into Integrated Units of Analysis ...................... 10
2.3Overview of sites ...................................................................................................... 11
2.4Discipline-specific description of Botswana sites ..................................................... 11
2.5Habitat integrity of the sites ...................................................................................... 12
3. IDENTIFICATION OF INDICATORS AND FLOW CATEGORIES ............................ 12
4. Indicators .................................................................................................................. 12
5. Introduction ............................................................................................................... 12
Indicator list for aquatic macroinvertebrates .................................................................. 12
Description and location of indicators ............................................................................ 13
Flow categories river sites .......................................................................................... 18
Inundation categories delta sites ................................................................................ 21
6LITERATURE REVIEW ............................................................................................... 22
6.1.1 Literature review - Macroinvertebrates of the Okavango ..................................... 22
6.1.2 Flows, Water level fluctuations and Macro-invertebrates ..................................... 23
Introduction .................................................................................................................... 23
Indicator 1: Channel dwellers in submerged aquatic vegetation ................................... 25
Life cycle attributes ........................................................................................................ 28
Indicator 1: Submerged vegetation (freshwater shrimp) ............................................... 28
Indicator 2: Marginal vegetation (Mayfly Family Baetidae) ......................................... 29
Indicator 3: Fast flowing water (Blackflies: Family Simuliidae) ...................................... 29
Indicator 4: Rock bottoms and stones (Caddisfly: Family Hydroptilidae) ...................... 29
Indicator 5: Fine Sediments ........................................................................................... 29
(Freshwater cockles, orb mussels: Family Unionidae; Sphaeridae) ............................. 29
Indicator 6: Backwaters (Coleoptera: Family Dytiscidae) .............................................. 30
Indicator 7: Pools in mopane woodland (fairy shrimp) .................................................. 30
Links to flow ................................................................................................................... 30
7. DATA COLLECTION AND ANALYSIS ...................................................................... 31
Methods for data collection and analysis ...................................................................... 31
Results 32
Macroinvertebrates Indicator 1: Channel dwellers in submerged vegetation ................ 33
Macroinvertebrates Indicator 2: Channel dwellers in marginal vegetation .................... 34
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EFA Botswana Aquatic Macroinvertebrates
Macroinvertebrates Indicator 3: Channel dwellers in fast flowing waters ...................... 35
Macroinvertebrates Indicator 4: Channel dwellers in stones and rock bottoms ............ 36
Macroinvertebrates Indicator 5: Channel dwellers in fine sediments ............................ 37
Macroinvertebrates Indicator 6: Channel dwellers in backwaters ................................. 38
Macroinvertebrates Indicator 7: Channel dwellers in seasonal pools in mopane
woodland .............................................................................................................. 39
Conclusion 40
REFERENCES .............................................................................................................. 41
APPENDIX A: FULL DESCRIPTIONS OF INDICATORS ............................................. 44
LIST OF FIGURES
Figure 2. 1: Upper Okavango River Basin from sources to the northern end of the Delta9
Figure 2. 2: The Okavango River Basin, showing drainage into the Okavango Delta and
the Makgadikgadi Pans ............................................................ 10
Figure 3. 1: Three representative years for Site 1: Cuebe River @ Capico, illustrating the
approximate division of the flow regime into four flow seasons 19
Figure 3. 2: Three representative years for Site 2: Cubango River @ Mucindi, illustrating
the approximate division of the flow regime into four flow seasons
................................................................................................. 19
Figure 3. 3: Three representative years for Site 3 Cuito River @ Cuito Cuanavale,
illustrating the approximate division of the flow regime into four
flow seasons ............................................................................ 20
Figure 3. 4: Three representative years for Site 4: Okavango River @ Kapoka
(hydrological data from Rundu), illustrating the approximate
division of the flow regime into four flow seasons .................... 20
Figure 3. 5: Three representative years for Site 5: Okavango River @ Popa (hydrological
data from Mukwe), illustrating the approximate division of the flow
regime into four flow seasons ................................................... 20
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EFA Botswana Aquatic Macroinvertebrates
LIST OF TABLES
Table 3.1 List of indicators for aquatic macroinvertebrates and those chosen to
represent each site ................................................................... 13
Table 3.3 Inundation categories for the Okavango Delta as recognised by the HOORC
inundation model ...................................................................... 21
Table 5.1 Predicted response to possible changes in the flow regime of Channel
dwellers in submerged vegetation in the Okavango River
ecosystem ................................................................................ 33
Table 5.1 Predicted response to possible changes in the flow regime of Channel
dwellers in marginal vegetation in the Okavango River ecosystem
................................................................................................. 34
Table 5.1 Predicted response to possible changes in the flow regime of Channel
dwellers in fast flowing waters in the Okavango River ecosystem
................................................................................................. 35
Table 5.1 Predicted response to possible changes in the flow regime of Channel
dwellers in stones and rock bottoms in the Okavango River
ecosystem ................................................................................ 36
Table 5.1 Predicted response to possible changes in the flow regime of Channel
dwellers in fine sediments in the Okavango River ecosystem . 37
Table 5.1 Predicted response to possible changes in the flow regime of Channel
dwellers in backwaters in the Okavango River ecosystem ...... 38
Table 5.1 Predicted response to possible changes in the flow regime of Channel
dwellers in seasonal pools in mopane woodland in the Okavango
River ecosystem ....................................................................... 39
Table 3.1 List of indicators for aquatic macroinvertebrates and those chosen to
represent each site ................................................................... 44
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EFA Botswana Aquatic Macroinvertebrates
ABBREVIATIONS
ABBREVIATION
MEANING
DTM
Digital Terrain Model
AquaRAP I
Aquatic Rapid Assessment one
AquaRAP II
Aquatic Rapid Assessment two
OKASS
Okavango Delta Scoring System
HOORC
Harry Oppenheimer Okavango Research Center
BIOKAVANGO Building
Local
Capacity in Biodiversity Management in the Okavango Delta
ACKNOWLEDGEMENTS
I want to acknowledge Dr Dallas who inspired me to initiate work on aquatic
macroinvertebrates in the Okavango Delta, the various teams that were engaged since 2003
to collect data in various sites of the Okavango Delta.
I also want to acknowledge my dear Husband - my rock, for the support, contribution and
advice throughout the research done on macroinvertebrates.
I extend my acknowledgements to HOORC library for the assistance on literature search.
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EFA Botswana Aquatic Macroinvertebrates
1. INTRODUCTION
1.1 Background
An Environmental Protection and Sustainable Management of the Okavango River Basin
(EPSMO) Project is being implemented under the auspices of the Food and Agriculture
Organization of the United Nations (UN-FAO). One of the activities is to complete a
transboundary diagnostic assessment (TDA) for the purpose of developing a Strategic Action
Plan for the basin. The TDA is an analysis of current and future possible causes of
transboundary issues between the three countries of the basin: Angola, Namibia and
Botswana. The Okavango Basin Steering Committee (OBSC) of the Okavango River Basin
Water Commission (OKACOM) noted during a March 2008 meeting in Windhoek, Namibia,
that future transboundary issues within the Okavango River basin are likely to occur due to
developments that would modify flow regimes. The OBSC also noted that there was
inadequate information about the physico-chemical, ecological and socioeconomic effects of
such possible developments. OBSC recommended at this meeting that an Environmental
Flow Assessment (EFA) be carried out to predict possible development-driven changes in
the flow regime of the Okavango River system, the related ecosystem changes, and the
consequent impacts on people using the river's resources.
The EFA is a joint project of EPSMO and the Biokavango Project. One part of the EFA is a
series of country-specific specialist studies, of which this is the Aquatic Macroinvertebrates,
for the Okavango Delta, Botswana.
1.2 Okavango River Basin EFA Objectives and Workplan
1.2.1 Project objectives
The goals of the EFA are:
·
to summarise all relevant information on the Okavango River system and its
users, and collect new data as appropriate within the constraints of the EFA
·
to use these to provide scenarios of possible development pathways into the
future for consideration by decision makers, enabling them to discuss and
negotiate on sustainable development of the Okavango River Basin;
·
to include in each scenario the major positive and negative ecological, resource-
economic and social impacts of the relevant developments;
·
to complete this suite of activities as a pilot EFA, due to time constraints, as input
to the TDA and to a future comprehensive EFA.
The specific objectives are:
· to ascertain at different points along the Okavango River system, including the Delta,
the existing relationships between the flow regime and the ecological nature and
functioning of the river ecosystem;
· to ascertain the existing relationships between the river ecosystem and peoples'
livelihoods;
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EFA Botswana Aquatic Macroinvertebrates
· to predict possible development-driven changes to the flow regime and thus to the
river ecosystem;
· to predict the impacts of such river ecosystem changes on people's livelihoods.
· to use the EFA outputs to enhance biodiversity management of the Delta.
· to develop skills for conducting EFAs in Angola, Botswana, and Namibia.
2 STUDY AREA
2.1 Description of the Okavango Basin
The Okavango River Basin consists of the areas drained by the Cubango, Cutato, Cuchi,
Cuelei, Cuebe, and Cuito rivers in Angola, the Okavango River in Namibia and Botswana,
and the Okavango Delta (Figure 2.1). This basin topographically includes the area that was
drained by the now fossil Omatako River in Namibia. Outflows from the Okavango Delta are
drained through the Thamalakane and then Boteti Rivers, the latter eventually joining the
Makgadikgadi Pans. The Nata River, which drains the western part of Zimbabwe, also joins
the Makgadikgadi Pans. On the basis of topography, the Okavango River Basin thus
includes the Makgadikgadi Pans and Nata River Basin (Figure 2.2). This study, however,
focuses on the parts of the basin in Angola and Namibia, and the Panhandle/Delta/Boteti
River complex in Botswana. The Makgadikgadi Pans and Nata River are not included.
Upper Okavango River Basin
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Okavango
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Figure 2. 1: Upper Okavango River Basin from sources to the northern end of the Delta
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EFA Botswana Aquatic Macroinvertebrates
Okavango River Basin
N
W
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Permanent swamps
Seasonal swamps
Figure 2. 2: The Okavango River Basin, showing drainage into the Okavango Delta and the
Makgadikgadi Pans
2.2 Delineation of the Okavango Basin into Integrated Units of
Analysis
Within the Okavango River Basin, no study could address every kilometre stretch of the river,
or every person living within the area, particularly like the Okavango Delta pilot site. Instead,
representative areas that are reasonably homogeneous in character may be delineated and
used to representative much wider areas, and then one or more representative sites chosen
in each as the focus for data-collection activities. The results from each representative site
can then be extrapolated over the respective wider areas.
Using this approach, the Basin was delineated into Integrated Units of Analysis
(EPSMO/Biokavango Report Number 2; Delineation Report) by:
dividing the river into relatively homogeneous longitudinal zones in terms of:
hydrology;
geomorphology;
water chemistry;
fish;
aquatic invertebrates;
vegetation;
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EFA Botswana Aquatic Macroinvertebrates
harmonising the results from each discipline into one set of biophysical river zones;
dividing the basin into relatively homogeneous areas in terms of social systems;
harmonising the biophysical river zones and the social areas into one set of Integrated Units
of Analysis (IUAs).
The 19 recognised IUAs were then considered by each national team as candidates for the
location of the allocated number of study sites:
Angola: three
sites
Namibia: two
sites
Botswana: three sites.
The sites chosen by the national teams are given in Table 2.1.
Table 2.1 Location of the eight EFA sites
EFA Site No
Country
River
Location
Panhandle at
6 Botswana
Okavango
Shakawe
7
Botswana
Khwai
Xakanaka in Delta
8 Botswana
Boteti Chanoga
2.3 Overview of sites
2.4 Discipline-specific description of Botswana sites
Site 6: Panhandle at Shakawe
The Upper Panhandle in the Okavango Delta receives water flowing from the Basin (Angola
and Namibia) through Mohembo. This site is relevant for the aquatic macroinvertebrates
because these organisms depend largely on the inundated floodplain where they refuge, and
complete their life cycle. This site (around Drotskys Cabins near Shakawe) has unique
backwaters area that host abundant crustacean (freshwater shrimp family Atyidae). For the
EFA study, this site and this particular indicator are very important. Its importance is also
highlighted by Dallas & Mosepele (2007) that describes that a total of 98 morphospecies
were recorded in this site during the study period in 2003.
Site 7: Eastern Delta around Xakanaxa
This area is within the Moremi Game Reserve, and has varied habitats that depend on the
flow of the main channel and on the rain within the mopane woodland. These habitats
include some marginal vegetation, fast flowing water, instream vegetation, backwaters,
lagoons and seasonal pools. During the 2003 survey, 125 morphospecies were recorded and
the only Leptophlebid may fly - Euthraulus sp. collected in this survey was observed in this
site (Dallas & Mosepele, 2007). This area also hosts unique taxa. According to Dallas &
Mosepele, 2007, an unusual record of a Setodes sp was observed, and it is presumed to be
a new species. The Seasonal flooded and rain-filled pools are unique and different from
other habitats with respect to their macroinvertebrates assemblage and that because they
host several crustaceans, including the Anostraca and Cladodocera, although the
macroinvertebrates fauna were dominated by Hemiptera and Coleoptera.
Site 8: Chanoga
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EFA Botswana Aquatic Macroinvertebrates
Chanoga site and the Boteti river are the outflows of the Delta. Their faunal assemblages
depend largely on the flow, the extent of the flood and the duration of water it receives. This
site did not get much water for the past years, until recently, it has been inundated for some
time. Aquatic macroinvertebrates form a major component on fish diet, and hence,
communities around this site benefit from fish for their source of protein. Fish is also sold at a
local market, and the money is used for other forms of livelihood.
2.5 Habitat integrity of the sites
3. IDENTIFICATION OF INDICATORS AND FLOW CATEGORIES
4. Indicators
5. Introduction
Biophysical indicators are discipline-specific attributes of the river system that respond to a
change in river flow by changing in their:
abundance;
concentration; or
extent (area).
Social indicators are attributes of the social structures linked to the river that respond to
changes in the availability of riverine resources (as described by the biophysical indicators).
The indicators are used to characterise the current situation and changes that could occur
with development-driven flow changes.
Within any one biophysical discipline, key attributes can be grouped if they are expected to
respond in the same way to the flow regime of the river. By example, fish species that all
move on to floodplains at about the same time and for the same kinds of breeding or feeding
reasons could be grouped as Fish Guild X.
Indicator list for aquatic macroinvertebrates
In order to cover the major characteristics of the river system and its users many indicators
may be deemed necessary. For any one EF site, however, the number of indicators is
limited to ten (or fewer) in order to make the process manageable. The full list of indicators
was developed collaboratively by the country representatives for the aquatic
macroinvertebrates discipline by Belda Mosepele (Botswana), Maria Filomena (Angola)
and Shishane Nakanwe (Namibia) - and is provided in Error! Reference source not
found.. Further details of each indicator, including the representative species of each
biological one, are given in Appendix A, and discussed fully in Chapter Error! Reference
source not found..
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EFA Botswana Aquatic Macroinvertebrates
Table Error! No text of specified style in document..1 List of indicators for aquatic
macroinvertebrates and those chosen to represent each site
Indic
Sites represented no more than ten
ator
indicators per site
Num
Indicator name
ber
1
2 3 4 5 6 7 8
1
Channel dwellers in submerged aquatic
X
vegetation
2
Channel dwellers in marginal vegetation
X
X
3
Channel dwellers in rapids (fast flowing
X
water)
Channels dwellers on cobbles and
4
X
boulders (rocks and stones)
5
Dwellers in fine sediment
X
X
6
Floodplain dwellers in backwaters
X
X
7
Dwellers in Pools or lagoons
X
Description and location of indicators
Aquatic macroinvertebrates - Indicator 1
Name: Channel dwellers in submerged aquatic vegetation
Description: Channel dwellers in submerged vegetation can be described as those dwellers
or aquatic macroinvertebrates that are mostly found in
vegetation that is often submerged in a channel. These habitats
are essential in providing food, and shelter against predators.
On site 6, the Upper Panhandle area, this habitat is available
and comprises mostly of vegetation commonly known as water
hornworth (Ceratophyllum demersum) and the coarse oxygen
weed (Lagarosiphon major). This vegetation is found in some
portions of the Upper Panhandle (around Shakawe site 6)
Representative species:
Freshwater shrimps. Family: Atyidae, genus Caridina.
It is represented by the species Caridina Africana or Caridina nilotica.
Other characteristic species:
Caridina nilotica feeds mainly on periphyton scraped from aquatic hydrophytes and on plant
detritus, but readily scavenges on the corposes of animals such
as fish, insects, and shrimps.
Flow-related location:
Not known. But in Site 6, in the upper panhandle, according to Mosepele's observation, this
species requires a minimum level of inundation on the habitat
above described. The vegetation needs to have some level of
inundation during all seasons, particularly in
September/November. Their abundance decline is probably
related to the low temperatures (in winter around June/July).
Their abundance declines in winter, around June-July when the
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EFA Botswana Aquatic Macroinvertebrates
water levels are reduced and in January before the floods
arrive. At the high water level (in April) the abundance decline is
noticeable, but around September to November this species
abundance is very high.
Known water needs:
In South Africa Rivers where it occurs, this shrimp is generally a shallow water littoral
inhabitant of fringing aquatic vegetation, but offshore benthic populations are known from
depths of up to 40 m in Lake Sibaya, (Moor et al., 2003). According to Moor et al., 2003,
freshwater shrimps prefer slightly saline conditions (2 to 3 parts per mil) in upper estuarine
reaches, but is intolerant of temperatures maintained below 10 degrees Centigrade's and
those above 30 degrees Centigrade's.
Aquatic macroinvertebrates - Indicator 2
Name: Channel dwellers in marginal vegetation
Description: Channel dwellers in marginal vegetation can be described as those dwellers or
aquatic macroinvertebrates that are mostly found in vegetation
that is on the margins of a channel. On site 6, the Upper
Panhandle area and site 7, the Moremi Game Reserve
Xakanaka area, this habitat is available and comprises mostly
of the vegetation commonly known as common reed
(Phragmites australis), hippo grass (Vossia cuspidata) and in
some areas a mixture of those with other plants like the fern
(Cyclosorus interrupts).
Representative species:
Family Caenidae (Ephemeroptera); Baetidae (Ephemeroptera);
and Polymitarcidae (tricoptera).
Other characteristic species:
Family Caenidae has several species of nymphs, relatively small (commonly known as
cainflies). They have two prominent square gills, humped backs
and the nymphs are relatively small.
Flow-related location:
Not known in the Okavango Delta. In some rivers in South Africa, it has been described that
this cainflies nymphs prefer slow or very slow streams habitats.
Known water needs:
Like any other macroinvertebrate, Caenids require some water to complete their cycle.
Aquatic macroinvertebrates - Indicator 3
Name: Channel dwellers in fast flowing water
Description: Channel dwellers in fast flowing water can be described as those dwellers or
aquatic macroinvertebrates that prefer highly oxygenated fast
flowing water. On site 7, the Moremi Game Reserve
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EFA Botswana Aquatic Macroinvertebrates
Xakanaka area, this habitat is available in portions of the
channel either with submerged or marginal vegetation. This
habitat hosts unique diversity of aquatic macroinvertebrates that
require high levels of oxygen.
Representative species:
Tricoptera (Family Leptoceridae) and Diptera (Family
Simuliidae)
Leptoceridae (also commonly known as cased caddisflies)
The Leptoceridae is the dominant family of Trichoptera and is regarded as the most diverse
of genera and species in the Afrotropical region, with 20 genera
and 306 species (Day et al., 2003)
Simuliidaes are known as blackflies and there are the known to be carries of the "river
blindness" sickness in many parts of the world. In Botswana,
the larva occurs in a diverse of habitats, particularly in shallow,
rapid streams. Observations by Mosepele, 2006 of adult
blackflies were made in the distal part of the Delta, in lake
Ngami, in 2006.
The female in the majority of Simuliidae species [common names: Buffalo Gnats (English);
mawi (Africa); pium, borrachudos (Brazil); potu (India); jejenes (Venezuela); bocones (Costa
Rica); rodadores (Cuba)] requires a blood meal for egg maturation, and it is this requirement
that makes species in this family important as biting pests and in the transmission of
parasites of the blood and skin in both man and warm-blooded animals. The most important
parasites in man transmitted by simuliid blackflies are the nematode Onchocerca volvulus
and Mansonella ozzardi. The former species is responsible for the human disease
"onchocerciasis or river blindness", affecting 17 million people in the Afrotropical and
Neotropical regions [http://blackflies.info/en/content/information].
In spite of the medical importance of some of the species, simuliids are also keystone
species in the ecology of running water because of their rare ability to filter dissolved organic
matter and make it available in the food chain. Blackflies are also important for environmental
monitoring of freshwater contamination, because immature stages (larvae and pupae) are
susceptible to both organic and inorganic pollution (e.g., effluent from sugar mills, slurry from
farms, insecticide and fertiliser run off from farms and plantations). Blackflies also have a
particular evolutionary interest as a morphologically conservative group with very extensive
cryptic speciation and reticulate evolution. [http://blackflies.info/en/content/information]
Other characteristic species:
There are various taxonomic problems in Simuliidae worldwide. Firstly, several regional
simuliid faunas are still poorly known and they are much in
need of biodiversity surveys and revisionary studies, where new
morphospecies are to be found. Second, the supraspecific
classification is currently unstable and problematic; many
species or species-groups are placed in the wrong genus, and
whether subgenera should be ranked as species groups or
genera is still in much debate. And thirdly, species limits
remains poorly defined for many taxa because of the presence
of species complexes ("sibling species").
Flow-related location:
Not known. But according to [Day et al., 2003], black flies can form 95% or more of the total
number of individual invertebrates collected from stones in
rapids and hence they can truly be considered to be specialists
of that swift-flowing aquatic biotope. Because of their
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EFA Botswana Aquatic Macroinvertebrates
abundance, black flies form an important component of the
aquatic food chain in swift-flowing water.
Known water needs:
These pupae of simuliids live in running water on stones and plant parts. According to
Gerber and Gabriel, 2002, blackflies require water that flows
fast at all seasons. The water level should be sufficient for good
oxygenation. These families will not tolerate or will not survive if
the flow reduces and deposition of decomposed material is
high.
Aquatic macroinvertebrates - Indicator 4
Name: Channel dwellers in rock bottoms
Description: Channel dwellers in rock bottoms are those dwellers that prefer to stay in rocks
or stones submerged in water in all seasons. They are unique
to these habitats and are generally described as filter-feeders;
Some families of tricoptera build narrow, fine-meshed finger-
shaped nets on or under rocks in streams.
Representative species:
Tricoptera family Philopotamidae
The larvae feed on fine detritus that the meshwork filters out of the water, which they then
clean off with their brush-like labrum. These are a caseless
caddisfly, with soft white labrum which is visible when extended.
Other characteristic species:
They live in low-salt concentrations. In site 8 around the Boteti river near Chanoga, there are
some areas in which the bottom is rocky and this family is
expected to occur.
Flow-related location:
Not known.
Known water needs: unknown
Aquatic macroinvertebrates - Indicator 5
Name: Channel dwellers in fine sediments
Description: dwellers in fine sediments are those invertebrates that are able to burrow into
sediments. Several studies indicate that chironomids,
oligachaets and sphaerids are commonly associated with
sediments.
Representative (species) Families: Unionidae and Sphaeriidae
Other characteristic species:
Flow-related location:
Not known.
16
EFA Botswana Aquatic Macroinvertebrates
Known water needs:
Not known
Aquatic macroinvertebrates - Indicator 6
Name: Floodplain dwellers in backwaters
Description: Floodplain dwellers in backwaters occur in site 6 and 7. The floodplain when
inundated with water from the main channel, creates an habitat
that family Planorbidae is abundant and that family
Coenagrionidae increases especially during flood recession.
Representative species:
Family Planorbidae common name are known as Orb snails,
their structure is generally flat shell, tightly coiled. It is known to host the bilharzias parasite.
According to Gerber & Gabriel, 2002, Planorbis prefers gravel beds or aquatic vegetation.
Other characteristic species: Family Coenagrionidae, known as damselflies. According to
Gerber & Gabriel, 2002, damselflies have slenders bodies, with
three leaf-like gills and pointed tips. Certain species of this
family have jointed gills. They prefer habitats with vegetation.
Flow-related location:
Not known.
Known water needs: this insects have a stage in their life cycles that requires water
Aquatic macroinvertebrates - Indicator 7
Name: floodplain dwellers in seasonal pools
Description: Seasonal pools in the mopane woodlands form an important habitat of site 7. It
hosts unique taxa of fairy shrimp and other smaller
crustaceans. These pools are mostly rich of green algae, the
preferred food for fairy shrimps.
Representative species: Family Lynceidae, Daphnia and Gammarus sp
Fairy shrimps are found in temporary pools. They do not have have a carapace. According to
Olsen et al., 2001; fairy shrimps swims upside down, have two pairs of eyes, one pair of
stalks, and two pairs of antennae, in males the second is modified as a pair of claspers. They
feed on plankton, especially algae. Representative species of fairy shrimps found in site 7
pools is Chirocephalus sp.
Clam shrimps (family Lynceidae) are characterised by a head covered by a hood-shaped
carapace; the female's ends in a point, while the male is blunt (Olsen et al., 2001). They feed
on plankton, they a rare and are found just above the bottom or free swimming in small
drying puddles (Olsen et al., 2001). Representative species: Lynceus sp.
Water fleas (Daphnia, Chydorus sps) have a bivalved transparent shell, covering thorax and
abdomen. According to Olsen et al 2001; water fleas head is
17
EFA Botswana Aquatic Macroinvertebrates
covered by a hood-shaped shell with a large eye, and the
abdomen ends in two claws. They are most filter-feed on
plankton, which is caught by the 4-6 pairs of thoracic limbs and
brought forward towards the mouth. A few species feed on
carrion, freshwater polyps or are predators. They are found in
all types of freshwater, except fast-flowing watercourses (Olsen
et al 2001). Water fleas are important for the recycling of
organic substances in ponds and lakes. They eat huge
quantities of planktonic algae, break down waste and are in turn
food for numerous small aquatic animals and fish, (Olsen et al.,
2001).
Other characteristics: Water fleas normally reproduce by parthenogenesis. Under certain
conditions such as too many solutes in the water, too little
food, a pond drying out, and when the temperature falls in
autumm the smaller males are produced, and they then
fertilise the females (Olsen et al., 2001). These females
produce thick-shelled dormant eggs, which can remain
unhatched for several years and in many species can withstand
desiccation and frost.
Flow-related location:
Not known.
Known water needs:
Pools or ponds require water for families mentioned above for reproduction. Pools can be
inundated for a short period of time, e.g. three months per year during the rainy season.
Flow categories river sites
One of the main assumptions underlying the EF process to be used in the TDA is that it is
possible to identify parts of the flow regime that are ecologically relevant in different ways
and to describe their nature using the historical hydrological record. Thus, one of the first
steps in the EFA process, for any river, is to consult with local river ecologists to identify
these ecologically most important flow categories. This process was followed at the
Preparation Workshop in September 2008 and four flow categories were agreed on for the
Okavango Basin river sites:
Dry season
Transitional Season 1
Flood Season
Transitional Season 2.
Tentative seasonal divisions for river Sites 1-5 are shown in Error! Reference source not
found. to Error! Reference source not found.. These seasonal divisions will be
formalised by the project hydrological team in the form of hydrological rules in the
hydrological model. In the interim they provide useful insights into the flow regime of the
river system suggesting a higher within-year flow variability of the Cuebe River and a higher
year-on-year variability of the Cubango River.
It is planned to use similar flow seasons for the remaining river sites: 6 and 8.
18
EFA Botswana Aquatic Macroinvertebrates
120
Wet
100
Trans 1
Trans 2
Dry
80
Year
Y
2
ear
60
Year
Y
1
ear
Year
Y
3
ear
40
20
0
O
N
D
J
D
F
M
A
M
J
J
M
J
A
S
Figure 3. 1: Three representative years for Site 1: Cuebe River @ Capico, illustrating the
approximate division of the flow regime into four flow seasons
1200
Wet
1000
Trans
n 1
Trans
n 2
Dry
800
Year 1
600
Year 2
Year 3
400
200
0
O
N
D
J
D
F
M
A
M
J
J
M
J
A
S
Figure 3. 2: Three representative years for Site 2: Cubango River @ Mucindi, illustrating the
approximate division of the flow regime into four flow seasons
19
EFA Botswana Aquatic Macroinvertebrates
250
1
Wet
2
Dry
200
ans
ans
Tr
Tr
150
Year 1
Year 2
100
Year 3
50
0
O
N
D
J
F
M
A
M
J
J
M
J
A
S
Figure 3. 3: Three representative years for Site 3 Cuito River @ Cuito Cuanavale, illustrating the
approximate division of the flow regime into four flow seasons
1000
900
Wet
We
800
Dry
Dr
Tra
Tr n
a s
n 1
s
Tra
Tr n
a s
n 2
s
Dry
Dr
700
600
Year 1
500
Year 2
400
Year 3
300
200
100
0
O
N
D
J
F
M
A
M
J
J
M
J
A
S
Figure 3. 4: Three representative years for Site 4: Okavango River @ Kapoka (hydrological data
from Rundu), illustrating the approximate division of the flow regime into four flow
seasons
1800
1600
Wet
1400
Dry
Trans
n 1
Trans 2
Dry
1200
1000
Year 3
00
Year 2
800
Year 1
600
400
200
0
O
N
D
J
F
M
A
M
J
J
M
J
A
S
Figure 3. 5: Three representative years for Site 5: Okavango River @ Popa (hydrological data
from Mukwe), illustrating the approximate division of the flow regime into four flow
seasons
20
EFA Botswana Aquatic Macroinvertebrates
The literature review (Chapter Error! Reference source not found.) and data collection
and analysis exercises (Chapter Error! Reference source not found.) are focused on
addressing what is initially expected to be nine main questions related to these flow seasons
(Error! Reference source not found.).
Table Error! No text of specified style in document..1 Questions to be addressed at the
Knowledge Capture Workshop, per indicator per site. In all cases, `natural'
embraces the full range of natural variability
Question
number
Season
Response of indicator if:
1
Onset is earlier or later than natural median/average
2
Dry Season
Water levels are higher or lower than natural median/average
3
Extends longer than natural median/average
4
Duration is longer or shorter than natural median/average - i.e. hydrograph
Transition 1
is steeper or shallower
5
Flows are more or less variable than natural median/average l
Onset is earlier or later than natural median/average synchronisation with
6
Flood season
rain may be changed
7
Natural median/average proportion of different types of flood year changed
8
Onset is earlier or later than natural median/average
Transition 2
9
Duration is longer or shorter than natural median/average i.e. hydrograph
is steeper or shallower
Inundation categories delta sites
The recognised river flow categories are not relevant in the Delta, where inundation is the
major driver of ecosystem form and functioning. The main inundation categories recognised
by the inundation model developed by the Harry Oppenheimer Okavango Research Centre
(HOORC) are used here (Error! Reference source not found.).
Table Error! No text of specified style in document..2
Inundation categories for the Okavango
Delta as recognised by the HOORC inundation model
Inundation Inundation
Description
category
category name
number
(The hydrologists and relevant Delta specialists are presently defining the main
inundation categories for the Delta, and these will be supplied to the Botswanan team
as soon as they have been finalised.)
21
EFA Botswana Aquatic Macroinvertebrates
6 LITERATURE REVIEW
6.1.1 Literature review - Macroinvertebrates of the Okavango
No studies have been conducted in the Okavango Delta that relates macroinvertebrates with
flow. The few studies conducted (six) on macroinvertebrates were to assess
macroinvertebrates distribution during the high and low water periods in 2000 and 2003
respectively. Other studies on macroinvertebrates were related to the impact of the aerial
spray of deltamethrin on macroinvertebrates.
For the purpose of this report, literature review included the publish journal articles, internet
search and any other available regional published information that relates
macroinvertebrates with flow and water needs were possible.
According to (Alonso and Nordin, 2003) aquatic rapid assessment survey during the high-
water period in 2000 focused in four focal areas of the delta, selected to represent areas in
the permanent swamp, the seasonal swamp and the drainage rivers, including the deltaic
and pool habitats. The study further looked at selected aquatic groups including Hirudinea
(leeches), Gastropoda (snails), Bivalvia (mussels), Decapoda (crabs and shrimps),
Heteroptera (water bugs), Ephemeroptera (mayflies) and Odonata (dragonflies and
damselflies). Heteroptera and Odonata were the most diverse group. Deltaic and temporary
pool habitats had different macroinvertebrate assemblages. Several new species and new
records for the delta were recorded.
The low-water level aquatic rapid assessment survey conducted in 2003 (Mosepele, In
Press; Dallas and Mosepele, In Press) included the same four focal areas of the Delta as
used for Aquatic Rapid Assessment during the high-water level survey. The
macroinvertebrates component was also published in scientific journal (Dallas and Mosepele
2007). Seventy-five samples were taken in a range of aquatic habitats at 29 georeference
points Over 180 morphospecies (approximately 63 families) were recorded during the
survey.
With respect to the different aquatic habitats sampled, the highest number of taxa was
recorded in marginal vegetation in the channels and lagoons, although inundated floodplains,
floating vegetation and marginal vegetation in backwaters also supported many taxa. The
fewest taxa were recorded in sediment. This survey, whilst representing a `snapshot' of the
system under low-water conditions, highlights the importance of maintaining a mosaic of
aquatic habitats in the Delta. Generally, more macroinvertebrate taxa were sampled during
this survey than in Aquatic Rapid Assessment (AquaRAP) I.
(Dallas and Mosepele, 2007) & (Dallas et al. 2007) provide a preliminary overview and
analysis of spatial distribution of aquatic macroinvertebrates in the Okavango Delta. The
studies aimed at assessing the aquatic biodiversity and water quality of the Okavango Delta
by examining zooplankton, macroinvertebrates and fish; and to use this information to
develop a monitoring programme for the Delta that would assist in its conservation and
management.
Macroinvertebrates associated with inundated floodplains in the Shakawe area were most
different from other deltaic habitats. The abundance in this habitat peaks in April, June and
September. In April and June are generally the peak flood season in Shakawe area, with
most of the floodplains inundated depending on the amount of the flood.
22
EFA Botswana Aquatic Macroinvertebrates
Notwithstanding the fact that flooding periods occur at different times of year at the different
focal areas; the flood arrives in Shakawe in February/March, peaks in April/May, and recedes
from June. In Guma areas, the flood arrives in April/May, peaks in June/July, and recedes
from August, while in Nxaraga/Xakanaka, the lower distal parts of the Delta, the flood waters
reach there around June/July, and recede from September (Dallas and Mosepele, 2007).
Rainfall occurs during December/January and February. Both the univariate (number of taxa
and abundance) and multivariate analysis do not suggest that macroinvertebrate
communities respond to the seasonal flood regime of the Okavango Delta, although further
studies were recommended to validate this finding.
6.1.2 Flows, Water level fluctuations and Macro-invertebrates
According to King and Brown (2006), increasing demands for water are degrading rivers
worldwide, resulting in a loss of vital goods and services they provide. Moreover, changes in
climate, low rainfall, floods, drought, growing population, has a negative impact in the aquatic
ecosystems and its organisms. The Okavango delta is among the more pristine wetland-
wilderness regions of the world (VanderPost, et al., 2005) and it is estimated that the input of
water to the Okavango Delta to be 66% from stream flow originating in Angola and 33% from
rainfall over the Botswana portion of the Okavango basin, resulting in flow variations that
make the Okavango Delta highly dynamic alluvial fan, with wetted extents varying from 6,000
to 12,000 km.
The Okavango Delta gets its water from the Angolan highlands that pass through Namibia,
before entering Botswana in Mohembo (Wilson and Dincer, 1976). Changes in flow and
water level will affect aquatic biodiversity, particularly of macroinvertebrates since there are
on the base of the food chain. Challenges to maintain a pristine ecosystem functioning that
provides all goods and services for its users is great particularly if steps to conserve and
protect the basic element of its existence water, is not done. This challenge is augmented
by the lack of important data on hydrology that relates to the ecology and biology of
macroinvertebrates of the Okavango Delta. Scientific data on macroinvertebrates that can be
linked to flow change, water levels dynamics are important to predict scenarios that can
describe impact of river change and be used to guide decision makers on monitoring and on
ecosystem management.
Miller (2007) was able to show that macro-invertebrates respond to water level fluctuations
through indirect environmental alterations that intensify with the magnitude and duration of
water level fluctuation. He observed that changes in community composition were associated
with interacting thresholds of reduced discharge and altered water quality (i.e., increased
conductivity and temperature) and that similar responses were observed at the population
level; growth and development alterations.
Introduction
Aquatic macro-invertebrates form a major component of the biota of aquatic ecosystems and
are associated with one or other aquatic habitat (Palmer et al., 1991, Dallas 1997, 2002;
Dallas and Day, 2007) such
as stony beds, floating vegetation, marginal and instream vegetation, gravel, sand and mud
(Dallas, HF, 2008). According to Dallas and Mosepele (2007), they are mostly primary
feeders (feeding on plant material), secondary feeders (feeding on planktonic or benthic
organisms) as well as consumers (near the base of the food chain). Some
macroinvertebrates help maintain the health of the water ecosystem by eating bacteria and
dead, decaying plants and animals (Wallace, 1996). They include insects, annelids,
molluscs, crustaceans and others ranging in size from about half 0.25 mm to several
centimetres.
23
EFA Botswana Aquatic Macroinvertebrates
Macroinvertebrates are animals without backbones that can be seen with a naked eye,
although some larval forms require a microscope for its identification. They are largely
dependent on the aquatic system they live and are sensitive to factors such as water quality,
water quantity (environmental flows), habitat and food availability (Dallas and Mosepele,
2007); making them essential components in the functioning of the aquatic ecosystems.
Therefore, macroinvertebrates are often referred to as health ecosystem indicators, because
they are frequently used as indicators of the general ecological condition.
24
EFA Botswana Aquatic Macroinvertebrates
Indicator 1: Channel dwellers in submerged aquatic vegetation
Main characteristics of Indicator 1
Table 4.1. List of species and the representative species for aquatic invertebrates
indicators.
Indicator
List of species
Representative
Why this species
Families (species)
Channel dwellers in
Caridina africana
Family Atyidae (Freshwater
Is one of the most important
submerged aquatic
Shrimp)
food items for numerous fish
vegetation
and other predators.
Generally are known to be
used as indicators of good
water quality.
Marginal vegetation
Ephemeroptera: Baetidae
Baetidae (Baetis sp)
These groups are common in
Odonata (Anisoptera):
Libellulidae (Libellula sp)
this habitat. The
Libellulidae
Ephemeroptera and Odonata,
are the only extant insects
with a paleopterous flight
mechanism. These two
relatively small orders,
sometimes classified as the
infraclass Paleoptera,
constitute the remnants of an
extensive fauna which mostly
became extint at the end of
the Mesoic Era (Daly, H.V. et
al, 1998). Mayflies and
odonates also constitute food
for fish.
Channel dwellers in fast
Diptera: Simuliidae and
Simuliidae and
·
Simulidae is also known
flowing waters
Tricoptera: Hydropsychidae
Hydropsychidae
as black-flies. It has
been recorded that this
family comprises of three
genera containing thirty-
five species, (Glegg,
1952). This family is also
known as pests of cattle.
· Tricopterans
also
known
as caddis flies. Some
types make for itself a
protective case from
pieces of stick, leaves,
stones, sand grains or
even snail-shell.
25
EFA Botswana Aquatic Macroinvertebrates
Tricoptera: Hydroptildae
This group make their case
when they are few months
old, having no gills, apparently
Channels dwellers on
they breathe through their
cobbles and boulders (rocks
body surface. The cases
and stones)
made when the creatures are
older are usually made of silk
only and are not tubular, but
flattened.
Unio sp. & Sphaerium sp.
Family Unionidae &
Freshwater cockles or orb
Sphaeridae
mussels are common names
for the bivalves Sphaerium
and Unio. These bivalves are
found primarily among plants
near baksn or lakes and rivers
Dwellers in fine sediment
in slow moving outflows
(Olsen at al., 2001). In the
Okavango Delta, some Unio
sps were observed in fine
sediments (Dallas and
Mosepele, 2007).
Dysticidae and Planorbidae
Coleoptera (Dytiscus sp.;
Diving beetles are
Hydrobius sp.) & Mollusca
represented by several
Ramshorn snails (Planorbis
species. The common species
sp.); Pond snail (Lymnaea
found in the Okavango Delta
stagnalis)
is known as "great diving
beetle" Dytiscus marginalis.
According to Olsen et al.,
2001; diving beetle larvae
pupate in a small hole in soft
soil near the water's edge.
After few weeks the beetle
emerges. Over winters as
adult in water lays eggs in
spring, usually in water. Most
are found all year round,
making them important for the
system where they live. Both
adults and larvae are
predators.
Moreover, according to
Weaving, A., 1977; beetles
make up the largest insect
order with around 300000
species; and are considered a
highly successful group of
insects, and certain of their
Floodplain dwellers in
characteristics have
backwaters (Seasonal
contributed towards this.
floodplain backwaters)
Beetles are also the largest
order in the animal kingdom,
and contains some of the
smallest and largest of
insects. Several families in the
suborder Adephaga are
aquatic, the most important
being the water beetles
(Dytiscidae) and the whirligig
beetles (Gyrinidae),
(Weaving, A., 1977).
Pulmonate snails (e.g.
Lymnae sps) have no gills;
they breathe through their
skin and use a kind of a lung
(Olsen et al., 2001). Almost
all are found on aquatic plants
or hanging beneath the
water's surface. In the
Okavango Delta these snails
are common in backwaters.
On the other hand, Pond
snails (e.g. Lymnaea
stagnalis) and ramshorn
snails (e.g. Planorbis sps)
26
EFA Botswana Aquatic Macroinvertebrates
rarely have completely regular
shells. Usually the exterior of
the shell has flat surfaces
separated by ridges. This
phenomenon is cased by the
snail being an intermediate
host for some kind of fluke,
causing growth irregularities
in the snail (Olsen et al.,
2001). Most ramshorn snails
have red blood.
Anostraca and Cladocera
Gammarus sp.; Lynceus sp.;
According to Olsen et al.,
Daphnia sp.
2001; the common freshwater
shrimp Gammarus pulex are
probably the most important
food for numerous fish and
other predators.
Water fleas (e.g. Daphnia
sps.) make up a large
Dwellers in Pools or lagoons
proportion of the food of
(seasonal pools in mopane
freshwater polyps (e.g.
woodlands)
Hydras), which are paralysed
by the stinging cells of the
tentacles. However, a small
(0.5 mm) water flea,
Anchistropus emarginatus,
which is rare, actually feeds
on Hydra, which is often
destroyed, (Olsen et al.,
2001).
Indicator 1: Channel dwellers in submerged aquatic vegetation
Main characteristics of Indicator 1
Submerged vegetation is an essential habitat; it provides food, and shelter for many
macroinvertebrates against predators. On site 6, the Upper
Panhandle area, this habitat is available and comprises mostly
of the vegetation commonly known as water hornworth
(Ceratophyllum demersum) and the coarse oxygen weed
(Lagarosiphon major).
Indicator 2: Marginal vegetation
Marginal vegetation can be found in most areas of the Okavango Delta. On site 6, the Upper
Panhandle area and site 8, the Moremi Game Reserve
Xakanaka area, this habitat is available and comprises mostly
of the vegetation commonly known as common reed
(Phragmites australis), hippo grass (Vossia cuspidata) and in
some areas a mixture of those with other plants like the fern
(Cyclosorus interrupts).
Indicator 3: Fast flowing water
Fast flowing water are unique habitats in which the water flows very fast, and hence the
oxygen levels are increased. These habitats host species of
macroinvertebrates that require oxygenated waters for their
survival.
27
EFA Botswana Aquatic Macroinvertebrates
Indicator 4: Rock bottoms
Rock bottoms or bedrocks habitats are generally found along the main stream or channel.
These habitats require some inundation so that they can host
certain species of macroinvertebrates. According to
[http://desertmuseum.org/books/], in rifles, obviously insects
must be able to hold on. Some mayflies are streamlined for
lessened resistance to the force of moving water, as they cling
to the rocks, plants or other substrates with sharp tarsal claws.
Indicator 5: Fine sediments
According to Townsend et al. (1997), species diversity of benthic macroinvertebrates was
highest at intermediate levels of peak flow frequency and that
invertebrated density decreased in frequently flooded streams
in New Zealand. Further, during low flow periods, periphyton
and a distinct community of sediment-tolerant benthic grazers
rapidly colonized sandy areas, (de la Cretaz, 2007). Unionid
mussels once were diverse and abundant in the river (Cape
Fear River), but the number of species present and their
densities have declined over the years, probably in response to
decreasing water quality and competition from the Asiatic clam
(Benke and Cushing, 2005).
Indicator 6: Backwaters
Backwaters serve as refuge for many macroinvertebrates taxa, particularly of coleopteran
and some snails. According to Quinn et al., (1991), referring to
the lower river Murray in South Australia, floodplains are
potentially most threatened by regulation and alteration of the
flooding regime.
Indicator 7: Pools
Pools in site 7 are a diverse habitat that is either filled with water from rain or water from the
main channel when the flood is high. These pools require a
certain amount of inundation for at least 3 months for various
species of macroinvertebrates, particularly rare crustaceans
(fairy shrimp) complete their life cycles. Certain species
dessicate when these pools dry, however they may hatch if
conditions are favourable, i.e. if pools have certain amount of
water for a certain period of time. According to
[http://desertmuseum.org/books/],insects living in pools or slow-
moving water tend to be bulkier. Pools provide habitat to a great
many aquatic beetles. Both larval and adult stages are aquatic
in the family Dytiscidae (predaceous diving beetles).
Life cycle attributes
Indicator 1: Submerged vegetation (freshwater shrimp)
Freshwater shrimps have external fertilisation, with the ova being fertilized as they are
extruded and then attached to the pleopods of females. According to Thorp and Covich
(2001), freshwater shrimps varies from species to species and regions. Furthermore, the
28
EFA Botswana Aquatic Macroinvertebrates
number of eggs produced per female is highly variable, ranging from 8 to 160, with fecundity
generally a linear function of total length. The incubation period depend on the water
temperature and varies from 12 to 24 days; zoeae larval lengths are approximately 4 mm at
hactching and these free swimming larvae pass through six stages (varies from 3 to 8) in
about three weeks.
Indicator 2: Marginal vegetation (Mayfly Family Baetidae)
Females of few baetidae species retain the fertilized eggs within the body, where they will
develop, a phenomenan called ovoviviparity, and these adult females might live one or two
weeks. Most mayflies of Alberta have one generation a year (univoltine); but several,
especially those in the family Baetidae, have more than one (usually two) generations a year
(multivoltine), Cliford (1991), the Bigoray River of west central Alberta, larvae of the new
generation first appear in late July. Larvae are found on soft, small-particle substratum.
Indicator 3: Fast flowing water (Blackflies: Family Simuliidae)
Female Blackflies lay eggs in hatches of 200-500 on vegetation or other objects in or
adjacent to fast flowing well oxygenated rivers, usually at dusk (Cox, 1993). Oviposition
behaviour is communal, eggs batches being deposited in close proximity to each other.
According to Cox (1993), the eggs are sensitive to desiccation, and if water levels are
lowered, they can be easily destroyed. The duration of the egg is dependent on temperature
but at tropical temperatures hatching to the larval stages takes 4-6 days. There are four
larval instars before pupae are formed. According to Cox (1993), blackfly pupae are conical,
firmly attached to the substrate and have characteristic anterior respiratory threads and the
duration of the pupal stages varies from 3 to 7 days.
According to [http://www.depweb.state.pa.us/blackfly/], the immature stages of blackflies are
aquatic and exclusively inhabit flowing streams and river. Life cycle include four stages: egg,
larva, pupa, and adult. All are aquatic except the adults, which leave the water to search for
food and mates.
Indicator 4: Rock bottoms and stones (Caddisfly: Family Hydroptilidae)
According to Wiggins (2004), adult caddisflies are obscure animals, usually active only at
night, although mass flights may be seen around water during evening hours. The smallest of
them all belong to the cocoon-making family Hydroptilidae and are from 2 to 5 mm long. At
temperate latitudes over much of North America, most caddisflies complete a single
generation in the course of one year. After hatching from egg, most larvae pass through five
larval moulting stages of instars and a resting pupal stage under water. Metamorphosis of
the resting pupa to the adult stage is completed within about three weeks at temperate
latitudes (Wiggins, 2004).
Indicator 5: Fine Sediments
(Freshwater cockles, orb mussels: Family Unionidae; Sphaeridae)
Unionidae are distinguished by a unique and complex life cycle. Most Unionids are of
separate sex (although some species, such as Elliptio complanata, are known to be
hermaphroditic). According to [http://zipcodezoo.com/Key/Animalia/Unionidae_Family.asp],
the sperm is ejected from the mantle cavity through the male's excurrent aperture and taken
into the female's mantle cavity through the incurrent aperture. Fertilized eggs move from the
29
EFA Botswana Aquatic Macroinvertebrates
gonads to the gills (marsupia) where they further ripen and metamorph into glochidia, the first
larval stage. Mature glochidia are released by the female and then attach to the gills, fins or
skin of host fish. A cyst is quickly formed around the glochidia, and they stay on the fish for
several weeks or months before they fall off as juvenile mussels which then bury themselves
in the sediment [http://zipcodezoo.com/Key/Animalia/Unionidae_Family.asp].
Indicator 6: Backwaters (Coleoptera: Family Dytiscidae)
Diving beetle (Dyticus marginalis) larvae pupate in a small hole in soft soil near the water's
edge. After a few weeks the adult beetle emerges. Overwinters as adult in water and lay
eggs in spring, usually in water, (Olsen et al. 2001). According to Stafford (2006), the
Dytiscidae family is one of the largest and most commonly encountered groups of aquatic
beetles. Both the adults and the larvae in this family are predaceous and feed on a wide
variety of smaller aquatic species. Although most adults are medium sized (15-25 mm),
some attain a length just over 30 mm.
Indicator 7: Pools in mopane woodland (fairy shrimp)
Female fairy shrimp carry their eggs in a ventral brood sac. The eggs are either dropped to
the pool bottom or remain in the brood sac until the mother dies and sinks. When the pool
dries out, so do the eggs. They remain in the pool bed until rains or floods and other
environmental stimuli hatch them. Hatching can begin within the same week that a pool
starts to fill. Average time to maturity is forty-nine days. In warmer pools, it can be as few as
nineteen days, http.//wikipedia.org/wiki/conservancy_fairy_shrimp]
Links to flow
Flood and drought disturbances are a fundamental part of most streams and rivers and play
a central role in the regulation of populations, the structuring of communities and the
functioning of aquatic ecosystems, (Lancaster et al. 2008).
Life history and behavioural adaptations, and these relate to flow regime components such
as disturbance timing, frequency and predictability is discussed by Lancaster et al. 2008.
Although in general, Lancaster et al. (2008), refers that unlike floods, the onset of drought is
often accompanied by proximate cues such as an increase in temperature and ionic
concentrations, and decrease in flow rate and water level. Lancaster et al. 2008 suggest that
particularly in the Trichoptera and Plecoptera, these cues may allow facultative entry into a
drought-resistant stage, or provide a signal to adjust growth and development rates
accordingly.
According to Lancaster et al. (2008), for aquatic insects, behaviours may be subdivided into
those facilitating within-stream during flood or drought. Instances of behavioural flood escape
are best known in the Hemiptera and Coleoptera, possibly because their ability to breathe air
allows them to persist out of water for relatively long time periods.
Summary
Freshwater aquatic macroinvertebrates are very important food for fish and other organisms.
Being at the bottom of the food web, they play a role in energy transfer and ecosystem
recycling. Some of these aquatic macroinvertebrates like blackflies can be important vectors
of diseases. They are responsible for transmitting onchocerciasis (river blindness) to millions
of people in tropical areas around the world [http://www.dep.web.state.pa.us/]. Other
important aquatic macroinvertebrates found in the Okavango delta are the ancient like
shrimps, and are rare called fairy shrimp. They occur mostly in Site 7 in seasonal pools
within the mopane woodland in Moremi Game Reserve. For this study, seven indicators were
indentified based on habitat, abundance and some knowledge of its importance and links to
communities; however, not much information so far exists on these organisms, especially
information on life cycles and their links to flow. Therefore, a refinement of indicators with a
30
EFA Botswana Aquatic Macroinvertebrates
combination of a continued data collection and field observations that relates to flow is
crucial. Some inferences made based on the best knowledge of certain aquatic
macroinvertebrates families require further research to validate the assumptions made.
Aquatic macroinvertebrates have mostly large groups and hence many families and species
that behaves and relate to flood, flow or other environmental conditions differently. In this
study knowledge was captured at the family level, therefore the report does not reflect
precisely what are the dynamics of each species within that group or family. Further studies
on species identification are required. Research to establish relationships between aquatic
macroinvertebrates and flow, flood, drought, habitat distribution, abundance is need to
understand the dynamics and role of these organisms in the Okavango Delta ecosystem.
7. DATA COLLECTION AND ANALYSIS
No new data were collected for this study.
Methods for data collection and analysis
No new data was collected specifically for this study. Knowledge was gathered to the
existing data and field observations from various research/data collection conducted
in the Okavango Delta.
6.3 Methodology
6.3.1 Collection of macroinvertebrates samples from major habitats at each site during low
and high flow seasons, all linked to flow.
Three sampling sites have been chosen for this study, namely Site 6 Upper Panhandle
around Shakawe); Site 7 Moremi Game Reserve (around Xakanaka); and Site 8 Lower
Delta (around the Boteti / Thamalakane river), following the basin-wide site delineation. Eight
different habitats have also been chosen in these sites to account for the various
macroinvertebrates species that can be impacted one way or the other by changes in water
flow. The habitats are: submerged vegetation, marginal vegetation, fine sediments, rapids or
fast flowing water, marginal vegetation in floodplains, pools or backwaters in floodplains,
pools or backwaters, and aquatic macrophytes.
Data for this study has previously been collected following the sampling methodology
described by Dallas, 2005.
6.3.3 Identification of macroinvertebrates to species or morphospecies.
All macroinvertebrates data from previous studies to be used to describe change in relation
to flow have been identified to family level.
6.3.4 Estimation of abundance of macroinvertebrates and analysis of community composition
linked to flow/inundation/hydraulic habitat/season
Abundance estimates and analysis of family composition of macroinvertebrates for each
habitat were done using the PRIMER v5 statistical package, but none were related to flow.
6.3.5 Prediction of changes of macroinvertebrates due to flow variations
31
EFA Botswana Aquatic Macroinvertebrates
With the available data and knowledge on macroinvertebrates, predictions curves will be
produced to explore changes in macroinvertebrates abundance due to flow variations. These
curves will therefore inform the possible scenarios in predicting impacts on
macroinvertebrates due to flow variations.
Results
No new data.
A summary of present understanding of the predicted responses of all aquatic
macroinvertebrates indicators to potential changes in the flow regime
32
EFA Botswana Aquatic Macroinvertebrates
Macroinvertebrates Indicator 1: Channel dwellers in submerged vegetation
Table Error! No text of specified style in document..3
Predicted response to possible changes in the flow regime of Channel dwellers in submerged
vegetation in the Okavango River ecosystem
Confidence in
Question
prediction (very
number
Season Possible
flow
change
Predicted response of indicator
low, low,
medium, high)
1
Onset is earlier or later than Relatively nil
medium
natural
Dry Season Water levels are higher or
Higher water levels implies more habitat available; lower than natural there will be
2
lower than natural
some decline in abundance of shrimps
medium
3
Extends longer than natural Reduced water level, reduced habitat, hence might affect spawning
High
Duration is longer or shorter
4
than natural - i.e.
hydrograph is steeper or
Transition 1 shallower
Flows are more or less
5
variable than natural
Onset is earlier or later than If the onset of the flood is earlier, changes in behaviour to adjust to arrival of water
6
natural synchronisation
may occur, however this can be relatively with no impact since the habitat might
medium
Flood
with rain may be changed
have received rain.
season
Natural proportion of
Natural floods or higher will provide nutrients therefore is good for the habitat and
7
different types of flood year the indicator; however if the flood changes during the flood season, some changes
medium
changed
may occur but not significant.
Onset is earlier or later than
8
natural
Transition 2 Duration is longer or shorter
than natural i.e.
9
hydrograph is steeper or
shallower
33
EFA Botswana Aquatic Macroinvertebrates
Macroinvertebrates Indicator 2: Channel dwellers in marginal vegetation
Table Error! No text of specified style in document..4
Predicted response to possible changes in the flow regime of Channel dwellers in marginal
vegetation in the Okavango River ecosystem
Confidence in
Question
prediction (very
number
Season Possible
flow
change
Predicted response of indicator
low, low,
medium, high)
Onset is earlier or later than If the dry season is earlier than natural, then the habitat will be lost for the
1
reproductive cycle of the mayflies. If the dry season is later than natural, the habitat medium
natural
will still have some moisture/water therefore their abundance might remain stable.
Higher water levels than natural, implies that the marginal vegetation will be
Dry Season Water levels are higher or
2
submerged for longer time, hence abundance might be stable. Lower levels than
medium
lower than natural
natural during dry season might have a negligible effect
Extended dry seasons will result in no habitat, no water and hence no
3
Extends longer than natural
High
macroinvertebrates
Duration is longer or shorter
than natural - i.e.
4
hydrograph is steeper or
Transition 1 shallower
Flows are more or less
5
variable than natural
Onset is earlier or later than Higher water levels than natural, implies that the marginal vegetation will be
6
natural synchronisation
submerged, hence reduced habitat available for spawning, hence less abundance
medium
Flood
with rain may be changed
of mayflies; lower than natural might not affect any change
season
Natural proportion of
Negligible as long as the habitat is available.
7
different types of flood year
medium
changed
8 Transition
2
Onset is earlier or later than
natural
34
EFA Botswana Aquatic Macroinvertebrates
Duration is longer or shorter
9
than natural i.e. hydrograph
is steeper or shallower
Macroinvertebrates Indicator 3: Channel dwellers in fast flowing waters
Table Error! No text of specified style in document..5
Predicted response to possible changes in the flow regime of Channel dwellers in fast flowing
waters in the Okavango River ecosystem
Confidence in
Question
prediction (very
number
Season
Possible flow change
Predicted response of indicator
low, low, medium,
high)
Onset is earlier or later than
It will affect the life cycle. Balk flies require fast flowing water for the immature stages
1
low
natural
Higher water levels implies more habitat available; lower than natural there will be some
2
Water levels are higher or
Dry Season
lower than natural
decline in reproduction
low
3
Extends longer than natural
Dry season extends therefore there will be reduced water level, reduced habitat, hence no
dwellers in these habitat
low
Duration is longer or shorter
4
than natural - i.e. hydrograph
Transition 1
is steeper or shallower
5
Flows are more or less
variable than natural
Onset is earlier or later than
If the onset of the flood is earlier, changes in behaviour to adjust to arrival of water may
6
natural synchronisation with
occur, however this can be relatively nil;
low
Flood
rain may be changed
season
Natural floods or higher will provide fast flowing water and a conducive oxygenated habitat.
7
Natural proportion of different
medium
types of flood year changed
Onset is earlier or later than
8 Transition
2
natural
35
EFA Botswana Aquatic Macroinvertebrates
Duration is longer or shorter
than natural i.e.
9
hydrograph is steeper or
shallower
Macroinvertebrates Indicator 4: Channel dwellers in stones and rock bottoms
Table Error! No text of specified style in document..6
Predicted response to possible changes in the flow regime of Channel dwellers in stones and
rock bottoms in the Okavango River ecosystem
Confidence in
Question
prediction (very
number
Season
Possible flow change
Predicted response of indicator
low, low, medium,
high)
Onset is earlier or later than
negligible
1
low
natural
Dry Season
Stones or rocks will have some flow, hence mayflies and caddisflies will have habitat
2
Water levels are higher or
low
lower than natural
3
Extends longer than natural
Reduced water level, reduced habitat, hence no macroinvertebrates
medium
Duration is longer or shorter
4
than natural - i.e. hydrograph
Transition 1
is steeper or shallower
5
Flows are more or less
variable than natural
If the onset of the flood is earlier, it relatively nil impact; but if it is later, rocks might be
Onset is earlier or later than
exposed to drought and hence desiccation or reduction of macroinvertebrates.
6
natural synchronisation with
medium
Flood
If rains are available before floods, rocks will have moisture and probably enough water to
rain may be changed
season
continue an uninterrupted life cycle.
Natural floods or higher will provide habitat. As long as the rocks are flooded the habitat will
7
Natural proportion of different
types of flood year changed
be conducive, and hence little change might occur.
low
Onset is earlier or later than
8
natural
Transition 2
Duration is longer or shorter
9
than natural i.e. hydrograph
is steeper or shallower
36
EFA Botswana Aquatic Macroinvertebrates
Macroinvertebrates Indicator 5: Channel dwellers in fine sediments
Table Error! No text of specified style in document..7
Predicted response to possible changes in the flow regime of Channel dwellers in fine
sediments in the Okavango River ecosystem
Confidence in
Question
prediction (very
number
Season
Possible flow change
Predicted response of indicator
low, low, medium,
high)
Onset is earlier or later than
Will affect habitatl
1
medium
natural
Higher water levels implies more habitat available; lower than natural there will be some
2
Water levels are higher or
Dry Season
lower than natural
decline in abundance of Unionidae, but negligible
medium
3
Extends longer than natural
Reduced water level, and extended periods of drought may result in desiccation of
macroinvertebrates in fine sediments.
medium
Duration is longer or shorter
4
than natural - i.e. hydrograph
Transition 1
is steeper or shallower
5
Flows are more or less
variable than natural
Onset is earlier or later than
If the onset of the flood is earlier or later will not affect the fine sediments dwellers.
6
natural synchronisation with
low
Flood
rain may be changed
season
Natural floods or changes in flood variability might have a negative effect on the habitat, but
7
Natural proportion of different
types of flood year changed
as long as there is some water in the sediments, these changes if any will be negligible
low
Onset is earlier or later than
8
natural
Transition 2
Duration is longer or shorter
9
than natural i.e. hydrograph
is steeper or shallower
37
EFA Botswana Aquatic Macroinvertebrates
Macroinvertebrates Indicator 6: Channel dwellers in backwaters
Table Error! No text of specified style in document..8
Predicted response to possible changes in the flow regime of Channel dwellers in backwaters
in the Okavango River ecosystem
Confidence in
Question
prediction (very
number
Season
Possible flow change
Predicted response of indicator
low, low, medium,
high)
Onset is earlier or later than
Negligible response
1
low
natural
Higher water levels will lead to inundation of more areas of the floodplain, hence habitat
2
Water levels are higher or
Dry Season
lower than natural
conducive for snails.
medium
3
Extends longer than natural
If it extends longer than natural, macroinvertebrates will stay in desiccation for longer
periods.
medium
Duration is longer or shorter
4
than natural - i.e. hydrograph
Transition 1
is steeper or shallower
5
Flows are more or less
variable than natural
Onset is earlier or later than
If the onset of the flood is earlier, changes in behaviour to adjust to arrival of water may
6
natural synchronisation with
occur, however this can be relatively with no impact since the habitat might have received
medium
Flood
rain may be changed
rain.
season
Natural floods or higher might impact on reproduction cycles, but not in high proportions;
7
Natural proportion of different
types of flood year changed
however if the flood is lower, they might change behaviour to accommodate changes.
medium
Onset is earlier or later than
8
natural
Transition 2
Duration is longer or shorter
9
than natural i.e. hydrograph
is steeper or shallower
38
EFA Botswana Aquatic Macroinvertebrates
Macroinvertebrates Indicator 7: Channel dwellers in seasonal pools in mopane woodland
Table Error! No text of specified style in document..9
Predicted response to possible changes in the flow regime of Channel dwellers in seasonal
pools in mopane woodland in the Okavango River ecosystem
Confidence in
Question
prediction (very
number
Season
Possible flow change
Predicted response of indicator
low, low, medium,
high)
Onset is earlier or later than
Negligible response
1
medium
natural
Dry Season
Higher water levels or lower than natural during dry season implies prolonged spawning
2
Water levels are higher or
lower than natural
and hence increase in abundance
medium
3
Extends longer than natural
Reduced abundance and desiccation for longer periods
High
Duration is longer or shorter
4
than natural - i.e. hydrograph
Transition 1
is steeper or shallower
5
Flows are more or less
variable than natural
Onset is earlier or later than
If the onset of the flood is earlier or later than natural it will not have any impact since the
6
natural synchronisation with
pools will mostly get water from rain during rainy season.
high
Flood
rain may be changed
season
Higher floods might prolong the timing for spawning and hence delays or adjustment in
7
Natural proportion of different
types of flood year changed
their life cycles. Abundance might reduce or not much affected.
medium
Onset is earlier or later than
8
natural
Transition 2
Duration is longer or shorter
9
than natural i.e. hydrograph
is steeper or shallower
39
EFA Botswana Aquatic Macroinvertebrates
Conclusion
This study used several data sets from previous research studies conducted in the
Okavango Delta. However, none of these data was collected in relation to flow, hence more
research is needed, specifically data that relates/links abundance and distribution of aquatic
macroinvertebrates and flow/flood levels. Several studies conducted in Delta looked at
spatial and temporal distribution of macroinvertebrates of some key habitats of the Okavango
Delta. Of recent, other areas like the Boteti river have been flooding regularly but there is no
a comprehensive studies on aquatic macroinvertebrates to quantify and establish their
abundance and distribution in relation to flow, and hence its dynamics in the Delta. Therefore
I recommend that more specific research studies should be conducted in detail to gather
information on aquatic macroinvertebrates distribution and abundance of key indicators
species and their linkages or relationships with the flood and flow regime in the Delta.
Moreover, more training and research on identification of macroinvertebrates to species level
is required and should be the focus of the basin wide decision makers to ensure good quality
data is collected and that a database on aquatic macroinvertebrates species for the
Okavango basin is generated.
40
EFA Botswana Aquatic Macroinvertebrates
FLOW-RESPONSE RELATIONSHIPS FOR USE IN THE OKAVANGO EF-DSS
Response curves to be inserted by the EF-DSS
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Dallas, H.F., and Mosepele, B., (2007). Preliminary survey and analysis of the spatial
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Dallas, H.F., (2002). Spatial and temporal heterogeneity in lotic systems: implications for
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43
EFA Botswana Aquatic Macroinvertebrates
APPENDIX A: FULL DESCRIPTIONS OF INDICATORS
Table Error! No text of specified style in document..10
List of indicators for aquatic
macroinvertebrates and those chosen to represent each site
Indicato
Sites represented no more than ten
r
Indicator name
indicators per site
Number
1 2 3 4 5 6 7 8
Channel dwellers in submerged aquatic
X
1
vegetation (Freshwater shrimps)
Channel dwellers in marginal vegetation
X
2
(Family Baetidae and Family
X
Libellulidae)
3
Channel dwellers in rapids (fast flowing
X
water) (Family Simuliidae)
Channels dwellers on cobbles and
4
boulders (rocks and stones) (Family
X
Hydroptilidae)
5
Dwellers in fine sediment (Family
X
X
Unionidae and Family Sphaeridae)
Floodplain dwellers in backwaters
X
6
(Family Dytiscidae and family
X
Planorbidae)
Dwellers in Pools or lagoons (fairy
7
shrimp)
X
44
EFA Botswana Aquatic Macroinvertebrates
The Okavango River Basin Transboundary Diagnostic Analysis Technical Reports
I
Diagnostic Analysis to establish a base of available
n 1994, the three riparian countries of the Okavango
scientific evidence to guide future decision making.
River Basin Angola, Botswana and Namibia agreed
The study, created from inputs from multi-disciplinary
to plan for collaborative management of the natural
teams in each country, with specialists in hydrology,
resources of the Okavango, forming the Permanent
hydraulics, channel form, water quality, vegetation,
Okavango River Basin Water Commission (OKACOM).
aquatic invertebrates, fish, birds, river-dependent
In 2003, with funding from the Global Environment
terrestrial wildlife, resource economics and socio-
Facility, OKACOM launched the Environmental
cultural issues, was coordinated and managed by a
Protection and Sustainable Management of the
group of specialists from the southern African region
Okavango River Basin (EPSMO) Project to coordinate
in 2008 and 2009.
development and to anticipate and address threats to
the river and the associated communities and
The following specialist technical reports were
environment. Implemented by the United Nations
produced as part of this process and form
Development Program and executed by the United
substantive background content for the Okavango
Nations Food and Agriculture Organization, the project
River Basin Trans-boundary Diagnostic Analysis
produced the Transboundary.
Final Study
Reports integrating findings from all country and background reports, and covering the entire
Reports
basin.
Aylward, B.
Economic Valuation of Basin Resources: Final Report to
EPSMO Project of the UN Food & Agriculture Organization as
an Input to the Okavango River Basin Transboundary
Diagnostic Analysis
Barnes, J. et al.
Okavango River Basin Transboundary Diagnostic Analysis:
Socio-Economic Assessment Final Report
King, J.M. and Brown,
Okavango River Basin Environmental Flow Assessment Project
C.A.
Initiation Report (Report No: 01/2009)
King, J.M. and Brown,
Okavango River Basin Environmental Flow Assessment EFA
C.A.
Process Report (Report No: 02/2009)
King, J.M. and Brown,
Okavango River Basin Environmental Flow Assessment
C.A.
Guidelines for Data Collection, Analysis and Scenario Creation
(Report No: 03/2009)
Bethune,
S.
Mazvimavi,
Okavango River Basin Environmental Flow Assessment
D. and Quintino, M.
Delineation Report (Report No: 04/2009)
Beuster, H.
Okavango River Basin Environmental Flow Assessment
Hydrology Report: Data And Models(Report No: 05/2009)
Beuster,
H. Okavango River Basin Environmental Flow Assessment
Scenario Report : Hydrology (Report No: 06/2009)
Jones, M.J.
The Groundwater Hydrology of The Okavango Basin (FAO
Internal Report, April 2010)
King, J.M. and Brown,
Okavango River Basin Environmental Flow Assessment
C.A.
Scenario Report: Ecological and Social Predictions (Volume 1
of 4)(Report No. 07/2009)
King, J.M. and Brown,
Okavango River Basin Environmental Flow Assessment
C.A.
Scenario Report: Ecological and Social Predictions (Volume 2
of 4: Indicator results) (Report No. 07/2009)
King, J.M. and Brown,
Okavango River Basin Environmental Flow Assessment
C.A.
Scenario Report: Ecological and Social Predictions: Climate
Change Scenarios (Volume 3 of 4) (Report No. 07/2009)
King, J., Brown, C.A.,
Okavango River Basin Environmental Flow Assessment
Joubert, A.R. and
Scenario Report: Biophysical Predictions (Volume 4 of 4:
Barnes, J.
Climate Change Indicator Results) (Report No: 07/2009)
King, J., Brown, C.A.
Okavango River Basin Environmental Flow Assessment Project
and Barnes, J.
Final Report (Report No: 08/2009)
Malzbender, D.
Environmental Protection And Sustainable Management Of The
Okavango River Basin (EPSMO): Governance Review
Vanderpost, C. and
Database and GIS design for an expanded Okavango Basin
Dhliwayo, M.
Information System (OBIS)
Veríssimo, Luis
GIS Database for the Environment Protection and Sustainable
Management of the Okavango River Basin Project
Wolski,
P.
Assessment of hydrological effects of climate change in the
Okavango Basin
Country Reports
Angola
Andrade e Sousa,
Análise Diagnóstica Transfronteiriça da Bacia do Rio
Biophysical Series
Helder André de
Okavango: Módulo do Caudal Ambiental: Relatório do
Especialista: País: Angola: Disciplina: Sedimentologia &
45
EFA Botswana Aquatic Macroinvertebrates
Geomorfologia
Gomes, Amândio
Análise Diagnóstica Transfronteiriça da Bacia do Rio
Okavango: Módulo do Caudal Ambiental: Relatório do
Especialista: País: Angola: Disciplina: Vegetação
Gomes,
Amândio
Análise Técnica, Biofísica e Socio-Económica do Lado
Angolano da Bacia Hidrográfica do Rio Cubango: Relatório
Final:Vegetação da Parte Angolana da Bacia Hidrográfica Do
Rio Cubango
Livramento, Filomena
Análise Diagnóstica Transfronteiriça da Bacia do Rio
Okavango: Módulo do Caudal Ambiental: Relatório do
Especialista: País: Angola: Disciplina:Macroinvertebrados
Miguel, Gabriel Luís
Análise Técnica, Biofísica E Sócio-Económica do Lado
Angolano da Bacia Hidrográfica do Rio Cubango:
Subsídio Para o Conhecimento Hidrogeológico
Relatório de Hidrogeologia
Morais, Miguel
Análise Diagnóstica Transfronteiriça da Bacia do Análise Rio
Cubango (Okavango): Módulo da Avaliação do Caudal
Ambiental: Relatório do Especialista País: Angola Disciplina:
Ictiofauna
Morais,
Miguel
Análise Técnica, Biófisica e Sócio-Económica do Lado
Angolano da Bacia Hidrográfica do Rio Cubango: Relatório
Final: Peixes e Pesca Fluvial da Bacia do Okavango em Angola
Pereira, Maria João
Qualidade da Água, no Lado Angolano da Bacia Hidrográfica
do Rio Cubango
Santos,
Carmen
Ivelize
Análise Diagnóstica Transfronteiriça da Bacia do Rio
Van-Dúnem S. N.
Okavango: Módulo do Caudal Ambiental: Relatório de
Especialidade: Angola: Vida Selvagem
Santos, Carmen Ivelize
Análise Diagnóstica Transfronteiriça da Bacia do Rio
Van-Dúnem S.N.
Okavango:Módulo Avaliação do Caudal Ambiental: Relatório de
Especialidade: Angola: Aves
Botswana Bonyongo, M.C.
Okavango River Basin Technical Diagnostic Analysis:
Environmental Flow Module: Specialist Report: Country:
Botswana: Discipline: Wildlife
Hancock, P.
Okavango River Basin Technical Diagnostic Analysis:
Environmental Flow Module : Specialist Report: Country:
Botswana: Discipline: Birds
Mosepele,
K. Okavango River Basin Technical Diagnostic Analysis:
Environmental Flow Module: Specialist Report: Country:
Botswana: Discipline: Fish
Mosepele, B. and
Okavango River Basin Technical Diagnostic Analysis:
Dallas, Helen
Environmental Flow Module: Specialist Report: Country:
Botswana: Discipline: Aquatic Macro Invertebrates
Namibia
Collin Christian &
Okavango River Basin: Transboundary Diagnostic Analysis
Associates CC
Project: Environmental Flow Assessment Module:
Geomorphology
Curtis, B.A.
Okavango River Basin Technical Diagnostic Analysis:
Environmental Flow Module: Specialist Report Country:
Namibia Discipline: Vegetation
Bethune, S.
Environmental Protection and Sustainable Management of the
Okavango River Basin (EPSMO): Transboundary Diagnostic
Analysis: Basin Ecosystems Report
Nakanwe, S.N.
Okavango River Basin Technical Diagnostic Analysis:
Environmental Flow Module: Specialist Report: Country:
Namibia: Discipline: Aquatic Macro Invertebrates
Paxton,
M. Okavango River Basin Transboundary Diagnostic Analysis:
Environmental Flow Module: Specialist
Report:Country:Namibia: Discipline: Birds (Avifauna)
Roberts, K.
Okavango River Basin Technical Diagnostic Analysis:
Environmental Flow Module: Specialist Report: Country:
Namibia: Discipline: Wildlife
Waal,
B.V. Okavango River Basin Technical Diagnostic Analysis:
Environmental Flow Module: Specialist Report: Country:
Namibia:Discipline: Fish Life
Country Reports
Angola
Gomes, Joaquim
Análise Técnica dos Aspectos Relacionados com o Potencial
Socioeconomic
Duarte
de Irrigação no Lado Angolano da Bacia Hidrográfica do Rio
Series
Cubango: Relatório Final
Mendelsohn,
.J.
Land use in Kavango: Past, Present and Future
Pereira, Maria João
Análise Diagnóstica Transfronteiriça da Bacia do Rio
Okavango: Módulo do Caudal Ambiental: Relatório do
Especialista: País: Angola: Disciplina: Qualidade da Água
Saraiva, Rute et al.
Diagnóstico Transfronteiriço Bacia do Okavango: Análise
Socioeconómica Angola
46
EFA Botswana Aquatic Macroinvertebrates
Botswana Chimbari, M. and
Okavango River Basin Trans-Boundary Diagnostic Assessment
Magole, Lapologang
(TDA): Botswana Component: Partial Report: Key Public Health
Issues in the Okavango Basin, Botswana
Magole,
Lapologang
Transboundary Diagnostic Analysis of the Botswana Portion of
the Okavango River Basin: Land Use Planning
Magole, Lapologang
Transboundary Diagnostic Analysis (TDA) of the Botswana p
Portion of the Okavango River Basin: Stakeholder Involvement
in the ODMP and its Relevance to the TDA Process
Masamba,
W.R.
Transboundary Diagnostic Analysis of the Botswana Portion of
the Okavango River Basin: Output 4: Water Supply and
Sanitation
Masamba,W.R.
Transboundary Diagnostic Analysis of the Botswana Portion of
the Okavango River Basin: Irrigation Development
Mbaiwa.J.E. Transboundary Diagnostic Analysis of the Okavango River
Basin: the Status of Tourism Development in the Okavango
Delta: Botswana
Mbaiwa.J.E. &
Assessing the Impact of Climate Change on Tourism Activities
Mmopelwa, G.
and their Economic Benefits in the Okavango Delta
Mmopelwa,
G.
Okavango River Basin Trans-boundary Diagnostic Assessment:
Botswana Component: Output 5: Socio-Economic Profile
Ngwenya, B.N.
Final Report: A Socio-Economic Profile of River Resources and
HIV and AIDS in the Okavango Basin: Botswana
Vanderpost,
C.
Assessment of Existing Social Services and Projected Growth
in the Context of the Transboundary Diagnostic Analysis of the
Botswana Portion of the Okavango River Basin
Namibia
Barnes, J and
Okavango River Basin Technical Diagnostic Analysis:
Wamunyima, D
Environmental Flow Module: Specialist Report:
Country: Namibia: Discipline: Socio-economics
Collin Christian &
Technical Report on Hydro-electric Power Development in the
Associates CC
Namibian Section of the Okavango River Basin
Liebenberg, J.P.
Technical Report on Irrigation Development in the Namibia
Section of the Okavango River Basin
Ortmann, Cynthia L.
Okavango River Basin Technical Diagnostic Analysis:
Environmental Flow Module : Specialist Report Country:
Namibia: discipline: Water Quality
Nashipili,
Okavango River Basin Technical Diagnostic Analysis: Specialist
Ndinomwaameni
Report: Country: Namibia: Discipline: Water Supply and
Sanitation
Paxton,
C.
Transboundary Diagnostic Analysis: Specialist Report:
Discipline: Water Quality Requirements For Human Health in
the Okavango River Basin: Country: Namibia
47
EFA Botswana Aquatic Macroinvertebrates
1