INTEGRATION OF FRESHWATER BIODIVERSITY IN...

P r e l i m i n a r y P l a n f o r F r e s h w a t e r B i o d i v e r s i t y M o n i t o r i n g i n t h e G a m b i a r i v e r b a s i n Page 1

INTEGRATION OF FRESHWATER BIODIVERSITY IN AFRICA’S DEVELOPMENT PROCESS:

INFORMATION COLLECTION AND DEMONSTRATION SITES

PRELIMINARY PLAN For the monitoring of

FRESHWATER BIODIVERSITY

IN THE GAMBIA BASIN

Wetlands International Africa Rue 111, Zone B, Villa № 39B, BP.25581

DAKAR-FANN. SENEGAL [email protected]


December 2009

WORKING GROUP

1. Coordination team AGBLONON Gabin NIANE Mamadou NIANG-DIOP Fatimata WADE Mawade

2. Consultants Dr. NDIAYE Abdoulaye Dr. NIANG-DIOP Fatimata Dr. Niasse Farokh Dr. SARR Alassane Dr. SEGA Moussa

FIGURE 1: GAMBIA BASIN


TABLE OF CONTENT 2. OBJECTIVE ................................................................................................................................................ 6

3. METHODOLOGY ................................................................................................................................... 6

3.1. Species and key habitats concepts .................................................................................................................. 6

3.2. Site selection criteria .............................................................................................................................................. 7

3.3. Species selection criteria ........................................................................................................................................ 7

4. PROPOSED SITES AND SPECIES TO BE MONITORED ............................................................... 8

4.1. Proposed sites to be monitored ....................................................................................................................... 8

4.2. Proposed species to be monitored ....................................................................................................................... 11

4.2.1. The crabs ......................................................................................................................................................... 11

4.2.2. The mollusks ................................................................................................................................................... 12

4.2.4. Birds ................................................................................................................................................................ 13

4.2.6. Fish ................................................................................................................................................................. 13

5. DATA COLLECTION .............................................................................................................................. 14

5.1. Crabs .............................................................................................................................................................. 14

5.2. Mollusks ......................................................................................................................................................... 15

5.3. Odonata .......................................................................................................................................................... 15

5.4. Birds ............................................................................................................................................................... 18

5.5. Plants .............................................................................................................................................................. 19

5.6. Fish ................................................................................................................................................................. 21

6. MONITORING INDICATORS ............................................................................................................... 21

6.1. Crab monitoring indicators .................................................................................................................................... 22

6.2. Mollusk monitoring indicators ..................................................................................................................... 22

6.3. Odonata monitoring indicators .......................................................................................................................... 24

3.4. Bird monitoring indicators ........................................................................................................................... 24

6.5. Plant monitoring indicators .......................................................................................................................... 25

6.6. Fish monitoring indicators ........................................................................................................................... 25

6.7. Fish monitoring indicators ........................................................................................................................... 26

7. MONITORING FREQUENCY ............................................................................................................ 29

7.1. Crabs .............................................................................................................................................................. 29

7.2. Mollusks ......................................................................................................................................................... 29

7.3. Odonata .......................................................................................................................................................... 29

7.4. Birds ............................................................................................................................................................... 29

7.5. Plants .............................................................................................................................................................. 29

7.6. Fish ................................................................................................................................................................. 30

8. ACTORS AND PARTNERS INVOLVED IN THE MONITORING ............................................... 30

PARTNERS .............................................................................................................................................................. 30


Organization for the development of the gambia river (OMVG) .......................................................................... 30

Wetlands International........................................................................................................................................... 30

Gambia ......................................................................................................................................................................... 30

Guinea ....................................................................................................................................................................... 31

Ministry of Environment ........................................................................................................................................ 31

Universities and research institutions ................................................................................................................... 31

Local Collectivities .................................................................................................................................................. 31

Guinea-Bissau .............................................................................................................................................................. 31

Ministry of Environment ........................................................................................................................................ 31


Senegal ......................................................................................................................................................................... 31


Local Collectivities .................................................................................................................................................. 31

REFERENCE/BIBLIOGRAPHY ................................................................................................................ 32

ANNEXES ...................................................................................................................................................... 37

Table of Figures:

Figure 1: Gambia Basin ....................................................................................................................................................... 2

Figure 2: Monitoring sites within Senegal and Guinean Gambia Basin .............................................................................. 9

Figure 3: Monitonring sites within Gambia Gambian Basin ............................................................................................. 10

Figure 4: Monitoring sites within Guinean Gambia Basin ............................................................................................... 11

Figure 5: Freshwater crabs within the Gambia Basin ....................................................................................................... 12

Figure 6: Freshwater odonate within the Gambia Basin .................................................................................................. 13

Figure 7: Freshwater fish within the Gambia Basin .......................................................................................................... 14


1. RATIONALE AND BACKGROUND

Supported by Wetlands International, IUCN implemented a program entitled, "Integration of

freshwater biodiversity in Africa’s development process: information collection and demonstration

site.” The program’s overall objective is to assess the conservation status of freshwater species

across the African continent and ensure effective consideration and use of data related to this

biodiversity, both in decision making and implementation of development activities in Africa. This

program has two phases. The first phase focuses on the collection of information to assess the

conservation status of selected taxa on IUCN’s private list. The second phase is linked to the

implementation of a case study on The Gambia River basin demonstration site.

This program enables water resources managers and environmental planners to integrate

information on freshwater biodiversity in the development process. The specific objective is to

ensure that environmental planning for the development of water resources throughout Africa is

based on the integration of reliable data, on the status, distribution and ecological conditions of

freshwater biodiversity for priority taxonomic groups such as crabs, mollusks, odonata, water birds,

aquatic plants and fish. These various species represent a certain ecological and socio-economic

interest because of their multiple roles. They are part of man’s diet and many other species. They

also provide habitat and refuge for others such as aquatic plants. Mollusks, for example, are capable

of containing many toxic chemicals and thus participating in the water purification phenomena.

Together with odonata and birds, they represent bio-indicators of the ecological status of aquatic

habitats.

However, despite the diversity and importance of species and habitats, freshwater ecosystems are

facing strong pressure and disturbances linked to human activities, among others. To the contrary,

even though dam construction responds to meeting economic needs, it can cause a lot of damage to

aquatic species and their habitats.

The Organization for the Development of The Gambia River (OMVG) comprising The Gambia,

Guinea, Guinea Bissau and Senegal, envisions the construction of a dam on the Sambagalou site.

Based on impact studies undertaken, the construction of this dam will undoubtedly cause a loss of

habitat. However, it is sometimes possible to compensate this loss by the protection and

conservation of natural habitats.


It is in this context that Wetlands International Africa, in partnership with the IUCN-Species

Programme and the OMVG has agreed on the development and implementation of a monitoring

plan for freshwater ecosystems biodiversity in The Gambia basin. This monitoring will provide

important information on species and habitats and it represents an opportunity to document changes

that might occur in the habitats. Hence, this will enable us take the necessary preventive or adaptive

actions.

2. OBJECTIVE The overall objective of the plan is to ensure the use of information on freshwater biodiversity in

development programs. It aims specifically to follow the changing trends of considered taxa and

their habitats in The Gambia River basin.

3. METHODOLOGY

3.1. Species and key habitats concepts

The Gambia River basin hosts a great number of species and attracts many other species such as

birds. This is due to the many services it provides but also because of its diversity of habitats

(estuaries, marshes, swamps, mudflats, etc.). A habitat is a functional unit composed of different

species that interact between them. The species are of great importance in maintaining the balance

of habitats. These species, some of which are referred to as "keystone species", are essential in

maintaining one or more communities. A keystone species may well be regarded as a species whose

loss or elimination can cause a major change in the ecosystem. For instance, regarding plant

species, they provide food for some animal species which are keystone species. The importance of

keystone species is not illustrated by the size of their current population, but rather by the action

they undertake to maintain a given community. Their disappearance leads to significant changes in

the functioning of the ecosystem. Similarly, species that are prolific in nature and can be considered

as key species is particularly true for invasive species.

In conservation biology, the term bio-indicator species is used to refer to species whose presence or

change in their populations lead to changes in the environment or communities of other species.

Keystone species play a fundamental role in maintaining biodiversity. Therefore, these species may

act as biological indicators or bio-indicators and enable us to determine the state of the ecosystem.

Key habitats are habitats which are important so much so that their degradation or loss can affect

one or more communities. According to Branquart (2004) key habitats are forest habitats that have a


particularly high protective value (or wealth), because they host many rare and endangered species.

Key habitats deserve to benefit from specific protection measures as regards their high protective

value.

3.2. Site selection criteria

The selection of monitoring sites was made in preparation for the construction of the Sambagalou

dam. It is therefore essential to take into account during the course of this selection the catchment

area of the reservoir-- upstream and downstream of the dam. In addition, a site that will most likely

not be affected by the dam has been taken into account (a control site). Considering these different

positions, the selection of sites to be monitored is based on the following criteria:

o The site’s ecological importance

o The role of site in biodiversity conservation

o Species richness

o The presence of rare or endangered species

o Endemism areas or sites rich in endemic species

o The ecological peculiarity (single habitat type or compulsory habitat for species or a given

community).

3.3. Species selection criteria During the first phase of the West Africa freshwater biodiversity assessment five freshwater taxonomic groups were selected and assessed based on the IUCN red list criteria. The taxonomic groups chosen were: fishes, plants, mollusks, odonates (dragonflies) and crustacean. Based on the regional assessment results the same taxonomic groups assessment results were brought at the level of the Gambia basin in this second phase. The results were reassessed for gaps by the researchers of the four country of the basin ( Senegal, Gambia, Guinea and Guinea Bissau). From the assessment some species were selected for monitoring based on the following criteria :

Endemic species

Threatened species

Rare species

Characteristic species

Economically important species

Invasive species

Potentially invasive species

Species indicating the environmental status (e.g. pollution)


4. PROPOSED SITES AND SPECIES TO BE MONITORED

4.1. Proposed sites to be monitored

Senegal

Sites Rationale Xcoord Ycoord

Site of Bara Close to the reservoir site

Ford of Damantan

Data available

Accessible

Taxa: fishes, birds, plants, odonata, crabs and mollusks

681853 ,76 1442636 ,35

Confluence point of the Gambia Niokolo

Interesting habitat because of the changing levels of the Gambia river

680729 ,54 1440436,78

Confluence point of the Gambia Nieriko

Interesting habitat especially when the Gambia overflows

The Nieriko is permanent, but undergoes a dry period at times with the dam

Can be permanent

675636 ,48 1476535,31

Simenti pond

Habitat directly connected to the Gambia and an important habitat for wildlife

684981 1400659

Kountadala pond

Habitat directly connected to the Gambia and important habitat for wildlife and currently invaded by Mimosa pigra and Mytragina inermis

683367 1441236

Wouring pond

Permanent pond that is in the process of being colonized in some parts by Mimosa pigra.

Deeper pond where there is always water, important habitat for wildlife, there is even a spawning area

683465,938 1462519,85

Oudassi pond Interesting habitat especially when The Gambia river overflows

Nieriko is constant, but undergoes a dry period at times with the dam

Could be permanent

682850 1448089,714


Padan pond Important site when considering biodiversity conservation

Banthantity pond Important site when considering biodiversity conservation

Sambangalou site Important site because of the dam’s physical presence.

FIGURE 2: MONITORING SITES WITHIN SENEGAL AND GUINEAN GAMBIA BASIN

Gambia :

a. Lower River ecological site; area for fish breeding but also first Ramsar site

b. Central River Region, Reserve area (Manatee)

c. Upper River ecology; wet mountainous area,

d. Through the Fouta Djallon water.


NOTE: There will probably be two more very important species for biodiversity in the

lower-river region:

FIGURE 3: MONITONRING SITES WITHIN GAMBIA GAMBIAN BASIN

Guinea Republic :

a. Ecosystem sites where villages will be displaced: Kounsi in the CRD of Balaki;

b. Ecosystem sites where villages will be endangered: Théwiirè;

c. Home site: Pakaya (Mali urban commune district).

In the site selection process, the following areas were considered for better sampling:

Those that will be flooded;

Those that will suffer the future impact of the project;

Those that will host displaced people

Based on what is already stated above, Guinean experts selected four sites including two sites that will be flooded.

The 4 identified sites contain the following ecosystems: Freshwater; Shrub lands; Savanna; Mountain; Bowes

They are all located in the Bafing Faleme protected area and are rich in biodiversity.

Sites to be monitored in Guinea XCoord YCoord

1. Selected site to be flooded for surveys in Thiéwiré in Lébékéré rural development commune (CRD);

782354.07 1338809.07

2. Selected site to be flooded for surveys in Parabanta in the Balaki rural development commune (CRD);

192592.93 1344434.65


3. Selected site that will be affected by the project’s future impacts for surveys in Kounsi in Balaki rural development commune (CRD).

193178.67 1343228.76

4. Potential site to host the displaced Pakaya District in the urban commune of Mali which is the host site

814556.00 1340886.47

FIGURE 4: MONITORING SITES WITHIN GUINEAN GAMBIA BASIN

4.2. Proposed species to be monitored

4.2.1. THE CRABS Only two species of crabs were identified in The Gambia river basin. Potamonautes ecorssei was collected in Wouroli Gué (Haute-Guinée), in Sanyiki près du Niokolo-Koba, in Niokolokoba and in Doufouroum between Niokolo-Koba and Banganré, and into Gambia River (Monod, 1969). Liberonautes latidactylus was found in Gué de Wouroli, Niokolo-Koba and into Gambia River .


FIGURE 5: FRESHWATER CRABS WITHIN THE GAMBIA BASIN

Facing the ecological changes that are the consequence of hydro-power works in the Gambia basin, it becomes necessary to monitor the evolution of these two species. There might be a third species of small crab that are usually found in muddy environments.

4.2.2. THE MOLLUSKS Mollusks play an important role in the functioning of aquatic ecosystems. They are part of the diet

of several species of aquatic vertebrates, especially fish. The mollusk populations participate in

water treatment by inhaling many toxic substances (heavy metals, pesticides...).

Because of their low mobility and life span, they are strong indicators of their environment’s

ecological status.

4.2.3. Odonata

The odonata represent a significant heritage but they also occupy an important place in the structure

and functioning of ecosystems and act as bio indicators on the quality of wetland habitats. The

odonata are a valid tool to evaluate the degradation of habitat quality and were used as indicator by

many authors.

We should however note that before undertaking the monitoring, it would have been wise to

conduct an inventory during at least two to three years to complete the available information in the

scientific literature on odonata wildlife in the basin. Such a study would enable to know the actual

autochthonous species that were mentioned and draw the odonata spectrum of the habitats.


FIGURE 6: FRESHWATER ODONATE WITHIN THE GAMBIA BASIN

4.2.4. BIRDS Water birds are defined as "a set integrating all taxonomic families, whose members are mainly birds who depend on wetlands for at least some part of their life cycle” (Rose & Scott 1994). These birds are excellent indicators on the status of habitats. Thus, we still agree that all surveyed species provide important information that contributes to the interpretation of results.

4.2.5. Plants

Aquatic plants play a very important role in aquatic ecosystems and more particularly in the

oxygenation and water purification ecological processes. They are also used as habitat and food for

animal species that live in these environments. For the human being, these aquatic plants are also

used in various manners. However, it should be mentioned that these plants can sometimes be

harmful, especially in cases where they proliferate at the expense of other species (invasive plants).

4.2.6. FISH


FIGURE 7: FRESHWATER FISH WITHIN THE GAMBIA BASIN

5. DATA COLLECTION Obviously, the choice of method depends on the objectives set forth but undoubtedly on the means

available for monitoring. The recommended methods in the monitoring plans must be simple

methods, relatively flexible, inexpensive and easily applicable, as well replicable in the future to see

changes over time. In the framework of this preliminary plan, it is necessary to develop a relatively

simple protocol to monitor the general trends of flora and fauna.

Because this plan is in line with an observatory meaning long-term monitoring, it may subsequently

be strengthened by integrating much more precise and rigorous approaches, in order to document

changes for both species and at the ecosystem levels.

5.1. Crabs

The crabs can be collected by hand under stones, in cracks and rock crevices, embankment holes,

vegetation etc. Afterwards, they will be preserved in alcohol.


5.2. Mollusks

The sampling protocol will take into account the main types of environments: ponds, streams,

tributaries and main river channel. Mollusks can be collected in a bucket (3 to 6 buckets per site),

by hand or using a dip net. The collected samples are passed through a 1 mm sieve. In the

laboratory, mollusks will be sorted, identified and counted.

In each prospection site, on-field measurements of physio-chemical parameters will be undertaken:

temperature, depth, bottom type, dissolved oxygen, salinity, nitrates and turbidity. These measures

will be carried out using a multi-parameter portable, a depth meter and a Secchi disk.

Parameters to record: the information that will be collected during the sampling

campaigns focuses on environmental conditions (temperature, salinity, conductivity,

dissolved oxygen, transparency, quantity of nitrates and phosphates, current strength, depth

and bottom type) and habitats or populations (to determine the species of and number of

collected mollusks, and the number of individuals collected per species).

Data analysis and treatment

First, the identified monitoring indicators (species richness and abundance) will be calculated.

Collected individuals will be identified until determining the species if possible in order to establish

the species richness (number of species) of each prospection site. If there is any doubt in

determining it, they will be sent to specialists. The species list will be established for each

prospection site.

A count of individuals collected per species will be conducted to determine the abundance of

species in the samples.

In a second phase, the Correspondence Factor Analysis (AFC) will be performed.

5.3. Odonata

5.3.1. Material to be used

Butterfly net

The butterfly net is made of a telescopic or fixed handle measuring approximately 1 to 2 m at the

end of which is attached a metal ring with a diameter of 30 to 50 cm provided with a pocket of

nylon, polyester or gauze that is more or less long and with various colors (white, green, black ...).

Kick net


The kick net is used to collect aquatic insects. It consists of a sturdy handle in one part, and a solid

iron or aluminum circle of about 30 cm in diameter, provided with a nylon bag inside an empty grid

of 800 to 300 microns, depending on the type.

Boxes to collect exuviae

Ringlets to collect Imagos

Flexible entomological pliers

Cyanide jar

Sorting trays

Digital Cameras

A digital camera, suited for close-up shooting, is strongly recommended.

Field Book

The field book is needed to record all information relating to the observation (names of the

observer(s), location, date, name of species, behavior, etc.).

5.3.2. Data collection

In each site, a number of stations will be identified according to the diversity of habitats. These

habitats can be i) stagnant water: ponds, lakes or open marshes, forest ponds, mountain lakes ii)

running water: streams and rivers with slow current, streams and rivers with troubled waters iii)

calm parts of large rivers and iv) terrestrial environments that can be quite far away from water

sources such as meadows, edges of woods, forest clearings.

Larvae, pupae and exuvia are being sought in aquatic habitat, more specifically in the water and

aquatic vegetation. Imagos will be sought on the vegetation that covers these areas and on the trees

and shrubs surrounding them.

In terrestrial environments that are more or less distant to aquatic habitats, adult in a maturing

process will be sought in the meadows, edges of woods and forest clearings where they can reunite.

Larvae and pupae

In the aquatic habitats, larvae and pupae are searched in the water and aquatic vegetation. The

collection is done with the use of the kick net.


After being mowed in the water, the content of the net is poured into a tray and is sorted by hand

with flexible entomological pliers. The larvae are put in a vial containing 70% ethanol with a label

bearing the date, place of harvest, habitat, geographic coordinates, and reference number. These

same data are reported in the field notebook.

Exuviae

The exuviae are searched on a band of approximately 50 cm on both sides of the bank along a

length that depends on the habitat’s size (approximately 8 to 80 m). The exuviae that are found are

then collected by hand, using a flexible entomological forceps and placed in the boxes provided for

this purpose (one or more boxes per habitat). Just like the larvae and pupae, exuviae is able to

determine the status of autochthonous species with certainty.

Imagos (adults)

The Odonata adults are sought in the surrounding water points but also on land more or less distant

from the aquatic habitats where adults in a maturation process meet. These are meadows, edges of

woods and forest clearings.

Imagos are captured with butterfly nets. The individuals captured after being mowed are gently

removed from the net pocket, avoiding holding them on their wings so as not to damage them. They

are then put into the cyanide jar, which kills them quickly. Once dead, they are placed in ringlets

with all the relevant reference (dates, collector’s name, harvest location, reference number, etc.).

When the insects are not treated immediately after being collected, one must dry them in the sun for

instance. Paradichlorobenzene can be put in the ringlets for better conservation.

Photographs of habitats and individuals (all ages) can usefully complete the information on the

species and their environments.

5.3.3. Data treatment and analysis

Harvests are put in tubes containing ethanol 70°. The identifications that can be done locally will be

done in the laboratory with the use of identification keys and/or with a comparison of reference

samples. In some cases, genitalia preparations are necessary for species identification. One will then

scour the genital parts to be mounted on a strip and compared them with the references.

The list of native species is derived from the identification of larvae, nymphs, exuviae and

individuals in mating.


However, it should be noted that with the changes of reproduction periods, one should regularly and

closely monitor over a period of two or three years to get an exhaustive list of targeted habitats

native species. We should also note that the odonata spectrum settlements depend on the list of

native species.

In the qualitative realm, one will need to compare the settlements’ populations on one hand and a

comparison of a settlement during the evaluation period (dry season and rainy season, from one

year to another).

In the quantitative realm, the averages of individuals/species captured according to various seasons

and years are compared. This will provide an indication on the populations’ evolution trend.

The counting of larvae and exuviae also give a good indication on the population size.

5.4. Birds

The distribution of water birds is closely linked to the availability of water and productivity of

wetlands. The Gambia basin, owing to the diversity of its habitats and resources, hosts a large

population of water birds. However, regular monitoring of these birds enables us to grasp their

distribution and population trends. It is within this framework that the count of water birds in Africa

(DOEA) can serve as reference to list the water birds already encountered in this basin. Moreover, it

is important to know the conservation status (good or bad) of these important bird sites; because the

smallest changes in these habitats may have serious consequences on bird populations. Thus, birds

are excellent bio-indicators of environmental change.


Monitoring will occur periodically in the different sites. In each site, geo-referenced counting points

are selected and counting transects determined by the distance between two successive counting

points. For small population, individual counting will be made; an estimate is made for large

populations. Thus, for each identified bird species, the number of individuals is counted. The

comments will be recorded on a counting card (ref. attached species sheet). The parameters related

to habitat will be considered (ref. attached site sheet). This method enables the study of bird

populations periodic changes in the sites and species encountered in different habitats.

5.4.2. Data analysis


A database will be created to triangulate the bird records (species richness, abundance, dominance)

with different environmental parameters (vegetation, water level, human impacts).

5.5. Plants

For plants, monitoring can be done at different levels (on the physiognomic scale, across

communities or ecosystems, across populations or species or even at the genetic level. In the

context of this work, we limit ourselves to monitoring across ecosystems and species. The first

refers to the vegetation structure itself that can be appreciated through the physiognomy, which is

particular to a given plant community.


Phyto-sociological methods are generally used to study aquatic plant communities. The transect

method is the most common. Transects are able to measure changes from one community to another

due to environmental gradients such as moisture. They are indicated by a stretched wire and

attached at both ends. Along these transects, frames measuring 1 m x 1 m will be installed using a

string and the angles will be marked with stakes. Data will be collected in these clearly defined

plots. As for the herbaceous, growing square will be used while for the high timber, 100 x 100

square meters with five 20 x 20 sub-squares will be used; Hence, this will create the floristic list and

species status as well as the environmental value of the ecosystems.

5.5.2. Parameters to collect

- It is important to geo-reference the sites and mark them in order to locate the sites for future visits.

- The water physio-chemical characteristics should be taken into account. These are namely pH,

oxygen and other chemical elements such as nitrates, phosphates, potassium, etc. that should be

measured.

- The floristic list: All species present in the plots will be listed. And those that will not be

identified in the field will be collected and subsequently identified using herbarium.

- Recovery: it is estimated using both the abundance (relative number of individuals of a species in

relation to the total number of individuals identified in the plot or frame) and dominance (covered

area, i.e. the projection on the ground of foliage coverage of all individuals of the targeted species).

This is found through the ratio of abundance-dominance determined by the Braun-Blanquet scale.

These factors vary based on the recovery.


Table: Factors of the Braun-Blanquet abundance dominance scale

Factors Recovery (R)

5 R > 75 %

4 50% < R <75 %

3 25 %<R<50 %

2 5 % <R<25 %

1 R <5 %

+ Rare

Note: Statement sheet: It is very useful to elaborate a statement sheet that includes the following:

- Date

- Location

- Transect orientation

- Number of transects

- Number of plots

- Species

5.5.3. Data analysis

For each species, the following parameters will be calculated: abundance, density, recovery,

dominance, frequency, relative frequency, relative dominance and importance value.

Abundance: the total number of individuals of each species in the total sample.

Recovery: the area occupied by individuals of a species. It is estimated using the projection on the

soil of the foliage coverage

Density: the number of individuals belonging to a species per area unit.

Relative density: the density of a species in relation to the density of all species.

Dominance: the area occupied (using the recovery) by a species in a settlement, per area unit.

Relative dominance: the area occupied by the species, using the recovery, in relation to the area

occupied by all species


Frequency: the distribution of a species in a settlement, i.e. the percentage of frames in the sample,

where one can find individuals of a species.

Relative frequency: the distribution of species in relation to the distribution of all species in the

sample

Important value: This is a composite index of relative density, relative dominance and relative

frequency which is the structural role of a species in a settlement. The important value is also used

to compare settlements between them, in terms of species composition and settlement structure.

VI = relative density + relative dominance + relative frequency

5.6. Fish


Experimental fishing will be done by using a battery of gill nets measuring 10 to 40 mm on the side

of the basin and 10 to 60 mm on the estuary side. Fish caught during the campaign will be identified

to determine the species, measured and counted. The gender of individuals and the sexual maturity

stages of the main species will be determined. Longlines traps and lines will be used. A sensitivity

electronic balance weighing 1 gram should be used.

5.6.2. Data analysis and treatment

First, the identified monitoring indicators (species richness and abundance) will be calculated.

Collected individuals will be identified until determining the species if possible, in order to

establish the species richness (number of species) of each prospection site. If there is any doubt in

determining it, the individuals will be sent to specialists. The species list will be established for

each prospection site.

A count of individuals collected per species will be conducted to determine the abundance of

species in the samples.

In a second phase, the Correspondence Factor Analysis (AFC) will be performed.

6. MONITORING INDICATORS Monitoring indicators will highlight the changing trends of species and their habitats. The indicators

are relatively numerous and can even be composed of a species or group of species which presence


inform us on the environment’s characteristics or the influence of other factors on the environment.

These indicators should be simple and easily understood by the various groups that will be

responsible for the monitoring.

6.1. Crab monitoring indicators

To evaluate and monitor the quality of crabs’ key habitats, the following indicators may be used:

Average Biomass (B)

It is determined by area unit and it enables the distinguishing of the settlements’ spatial and

temporal variations

Abundance (A)

The abundance is determined by the number of individuals of a species

6.2. Mollusk monitoring indicators

The composition and structure of animal populations are directly influenced by environmental

conditions. Mollusks are proving to be good indicators to assess the status of habitats where they

grow. Their limited mobility prevents them from fleeing when there are disturbances in the

environment, which permits them to provide a reliable illustration of the environmental conditions

where they live, unlike fish and other mobile species.

Many studies showed that the installation of a freshwater reservoir supports the abundance of

mollusks with lentic affinity (Mollusques Gastéropodes pulmonés, et autres Bivalves)). In

addition, the reservoirs create the favorable conditions for the development of the plants which

constitute an excellent habitat for several mollusc species. The building of the dam and the other

related infrastructures could cause a fragmentation of the habitats regarded as one of the most

important factors of disappearance of the species. The reduction of the flood plains downstream

from the dam could cause the a reduction in the abundance of mollusks. After the construction of

the dams, the oxygenated running water are often replaced by calm waters. These new hydrological

conditions could be unfavourable to the mollusc species of running water such as Mutela dubia

dubia and Aspatharia dahomeyensis.

Several types of methods (univariate and multivariate) are used to analyze changes in mollusks’

population structure.

Because of their simplicity and simple calculation, some univariate methods have been preferred

over a long period of time. These techniques permit to characterize the communities’ general trends,


study their variations and deduct the underlying causes. However, they do not take into account the

species and do not consider changes in specific composition (Grall et al., 2006).

Being more sensitive than univariate methods in general, multivariate methods are relatively recent

because their use requires computer materials and specialized and powerful softwares (Grall et al.,

2006). However, they are much more complex compared to other techniques, they require

significant work on data preparation and processing and interpretation of results is often difficult,

limiting their use by developers (Grall et al., 2006).

For this study, we suggest the use of methods with one single descriptor that are easier to interpret.

Two measures could be used to evaluate the effects of hydraulic works on mollusks’ species:

1) Abundance of species determined by the number of individuals

The Abundance is determined by the number of individuals of a species in the sample.

2) Species richness (S)

The richness and abundance of bivalve mollusks can provide information on the general

quality of the ecosystem. The composition and the structure of the settlements directly reflect the

disturbances which the organism undergo. If the dam is effectively operating, the various reactions of the

species will be translated at the level of their abundance and number.

Facing changing of environmental conditions, the species will go through three types of reaction

according to their sensitivity (Grall et al., 2006):

The most sensitive will disappear

Because of their sedentariness (cannot flee), large the bivalves are very sensitive to the changes of the environmental physical conditions (pollution, turbidity, hydrology). These large bivalves are represented in the basin of Gambia by the following species:

Coelatura aegyptiaca Mutela dubia dubia Aspatharia dahomeyensis. Pleidon ovatus

Etheria elliptica -

The indifferent will maintain themselves

The tolerant and opportunistic will take advantage of the newly introduced conditions and

develop themselves

It is also based on the model of Pearson and Rosenberg (1978) predicting that the more the

disturbance is strong the weaker the specific richness is


3) This pecies richness can be used to analyze the settlement’s taxonomic structure (e.g.

number of mollusks species). It is also able to distinguish spatial variations: the fauna

rich areas and poorer areas as well as temporal variations: the minimum and maximum

depending on seasons and stations (Grall et al., 2006). However, it contains a drawback

in that it is highly dependent on sample size (number of species sampled increases with

the surface sampled) and habitat type (species richness varies according to substrate

type, depth and salinity).

In addition to these two parameters, it would also be necessary to measure water physio-

chemical parameters given the importance they can have on the environment’s general

conditions and mollusks species distribution. These parameters are: temperature,

turbidity, depth, bottom type, dissolved oxygen, vegetation, content of nitrates and

phosphates.

6.3. Odonata monitoring indicators

the monitoring indicators are :

1. The diversity of autochtones Odonates habitats (spectrum odonatologic). This diversity, once

known, will make it possible to monitor the appearance or the disappearance of species in

relation to the implementation of the dam in the selected habitats.

2. The relative abundance of the populations during sampling (captured exuvies, individuals);

this indicator will make it possible to evaluate the population’s fluctuation of the species in

relation to the implementation of the dam.

3. 10. The larval odonatologic productivity will make it possible to evaluate the rate of

reproduction of the species to be monitored in the selected habitats.

3.4. Bird monitoring indicators

The indicators to monitor birds are:

Species richness

Abundance

Dominance

The environmental parameters (vegetation, water level, human impacts).


These parameters are important for bird monitoring. The Species richness gives the number of species found in the area before giving their status (endangered or not). The abundance linked to Species richness will give the trends of all species (stable, increasing, decreasing, or unknown. The dominance will give an idea of species or group of species which are dominant in different habitats. All these will be analysis according to environmental parameters such as vegetation fluctuation, water quality and quantity, pollution, and other human impacts. With the implementation of the dam the changes are expected to happen on those indicators for rhe bird to be monitored.

6.5. Plant monitoring indicators

The construction of the dam will induce probably some modifications in the ecosystem that’s why; it is important to elaborate indicators which can be used for the monitoring. Regular quantitative data concerning specific composition and species dynamic through these following parameters will inform about ecosystem changes.

The population size (species whose populations are decreasing or those whose populations

are prolific ;)

The abundance of species

The distribution of species

The change in floristic composition

The species richness

The presence of exotic species

6.6. Fish monitoring indicators

These indicators will be determined on two levels: species and habitats.

• For species, four metrics are taken into account:

Catch effort per unit (PUE) which indicates the relative abundance of species.

The average relative length of individuals. For each individual, we will calculate its length

in relation to the minimum (m) and maximum (M) observed for individuals of the same

species in all fisheries: (observed length-m) / (Mm). Individual values are then averaged per

fishing. The lower the value one can assume that the population consists of young

individuals, as it was also confirmed by the correlation which was observed during the

Garafiri dam impact study Garafiri (IRD-BCEOM-BRLI, 2003) between this variable and


the percentage of juvenile individuals in the settlement. This variable should increase if a

disturbance reduces the recruitment.

The relatively average condition factor. The condition factor (K = P/L3, P= body weight in

grams, L = length in cm) will be calculated for all individuals, then converted to relative

value given the maximum and minimum observed for each species in all fishing. Individual

values are then averaged per fishing. A low value corresponds to a low status of individuals

throughout the population.

The percentage of mature individuals: Proportion (%) of mature individuals by the total

number of individuals will be calculated. A low value may indicate a disruption of

reproduction.

• For habitats: One should note that many methods have been developed to quantify the impact of

disruptions that the streams on ecological systems experience. With regard to fish populations, an

approach that is increasingly used, including in the tropics is the index of biotic integrity (Index of

Biotic Integrity or IBI) developed first in North America (Karr 1981).

6.7. Fish monitoring indicators

These indicators will be determined on two levels: species and habitats.

• For species, four metrics are taken into account:

Catch effort per unit (PUE) which indicates the relative abundance of species. This metric is

based on the fact that in a disturbed realm the density of species is supposed to be less than

in an undisturbed one.

The average relative length of individuals. For each individual, we will calculate its length

in relation to the minimum (m) and maximum (M) observed for individuals of the same

species in all fisheries: (observed length-m) / (Mm). Individual values are then averaged per

fishing. The lower the value one can assume that the population consists of young

individuals, as it was also confirmed by the correlation which was observed during the

Garafiri dam impact study Garafiri (IRD-BCEOM-BRLI, 2003) between this variable and

the percentage of juvenile individuals in the settlement. This variable should increase if a

disturbance reduces the recruitment. Increase of this variable indicates that there is less

number of fish reaching the adult age.


Average length and average relative length are differents concepts; What is taken here into

account is the second one which give indications of rate of young individuals among the

population. The average length is another concept which indicate to what extend, i.e up to

what length. a species can grow up. Changing in average length may indicate overfishing

or a very poor biological productivity of an environnemnt as it has been documented for

two marine species, Galeoides decadactylus and Pseudotolithus senegalensis that showed a

shorter maximum length in the coast of Biafra than off Congo and Ivory Coast.

The relatively average condition factor. The condition factor (K = P/L3, P= body weight in

grams, L = length in cm) will be calculated for all individuals, then converted to relative

value given the maximum and minimum observed for each species in all fishing. Individual

values are then averaged per fishing. A low value corresponds to a low status of individuals

throughout the population.

The percentage of mature individuals: Proportion (%) of mature individuals by the total

number of individuals will be calculated. A low value may indicate a disruption of

reproduction, i.e., reproduction of species with low value is affected by the disturbance

• For habitats: One should note that many methods have been developed to quantify the impact of

disruptions that the streams on ecological systems experience. With regard to fish populations, an

approach that is increasingly used, including in the tropics is the index of biotic integrity (Index of

Biotic Integrity or IBI) developed first in North America (Karr 1981).

Index of Biotic Integrity

The originality of this index is to take into account certain descriptors (metric) reflecting the

functioning and diversity of fish populations and whose response to a disturbance of the

environment is already known. Such an index has been developed for the Konkoure basin in a

previous study (Hugueny et al 1996) and its effectiveness was tested during the impact study of the

pollution of a bauxite processing factory.

To calculate the IBI, one will use the same metrics as those defined for the Konkouré (Hugueny et

al 1996) in addition to indicators of condition, reproduction and recruitment:

‐ Metric 1: Number of species per fishing. This metric is based on the assumption that a

disturbed environment has fewer species than an undisturbed one because species intolerant

to disturbance (s) will not be there


‐ Metric 2: Number of Mormyrides species.

‐ Metric 3: Number of Cichlides species.

‐ Metric 4: Number of great benthic Siluriforms species.

‐ Metric 5: Percentage of individuals belonging to omnivorous species. The number of

omnivores is supposed to increase in disturbed environments where more specialized food

sources are rare or absent. Subsequently, the inverse of this metric is added to the final IBI

(see below).

‐ Metric 6: percentage of individuals belonging to invertivores species.

‐ Metric 7: percentage of individuals belonging to piscivorous species at an adult stage

without necessarily being strictly piscivorous.

‐ Metric 8: Total PUE (in numbers) per fishing. In a disturbed environment the species

density is supposed to be less than that observed in an undisturbed environment.

The metric 1 to 4 report on the settlement’s functional diversity determined by the number of

species found in different taxonomic categories. The underlying assumption is that a disrupted

settlement will be less diversified than a non-disrupted settlement.

Metrics from 5 to 7 take into account the trophic structure, with the underlying assumption that

individuals on a special diet will be disadvantaged compared to omnivores facing a disruption

affecting food resources.

After being centered and reduced (multiplied by -1 in the case of the metric 5) the other 8 metric are

added to form the IBI. Low IBI values are then interpreted as resulting from the possible action of

one or more environmental disturbances.

In addition to the initial metric, we took into consideration 3 additional features:

Relative average length of individuals

Relative average condition factor

The percentage of mature individuals.

These three variables are centered, reduced (multiplied by -1 in the case of the relative length) and

aggregated to the IBI which is more sensitive to disturbances that can be induced on the biology of


species (reproduction and condition). To be clearer these 3 metrics give indications on reproduction

(relative average length and percentage of mature individuals) and feeding condition (Relative

average condition).

Measurement of physio-chemical parameters:

To assess the quality of fish habitats, it would also be necessary to measure water physio-chemical

parameters on the following elements: dissolved oxygen, salinity, depth, temperature, nature of

substrate, nitrate, phosphate and toxic chemicals.

7. MONITORING FREQUENCY

Within the framework of the species monitoring, it is important to clearly describe the frequency of

the monitoring which is related to the time interval to which the data must be collected. The period

of collection constitutes a determining factor in the nature of the results which will be obtained.

Indeed, according to the species and according to the periods of the year (for example rainy and dry

season), there is important variations of biological information of the species. For each taxon, a

frequency of monitoring was described.

7.1. Crabs

Bi-annual (one in dry season and another one in rainy season) sampling campaigns will be

conducted to better understand the composition and distribution of species and the inter-season

variability in the relative abundance of different species

7.2. Mollusks

Bi-annual (one in dry season and another one in rainy season) sampling campaigns will be

conducted to better understand the composition and distribution of species and the inter-season

variability in the relative abundance of different species

7.3. Odonata

Sampling will be done during the dry and rainy seasons, once every three years.

7.4. Birds

For the first year, a bi-monthly sampling should be undertaken in all identified sites in order to see

the population dynamics according to the environmental parameters.

7.5. Plants


The first monitoring will be conducted twice a year in the different sites already identified. The first

will be conducted during the dry season between March and April, and the second towards the end

of the rainy season between September and October. After an initial visit which will serve as

baseline, the monitoring must continue every year in order to provide maximum information that

may help at some point to assess evolution trends of flora and aquatic and semi-aquatic vegetation.

7.6. Fish

The first exploratory mission to select monitoring sites (GPS positions) and collection of general

information on the environment must be undertaken. Afterwards, four quarterly sampling

campaigns will take place at significant periods of the seasonal hydrologic cycle of The Gambia

river

‐ August / September: characterizing the rainy season

‐ October / November / December: characterizing the end of the rainy season

‐ February / March / April: characterizing the dry season

‐ May / June / July: characterizing the beginning of the rainy season

8. ACTORS AND PARTNERS INVOLVED IN THE MONITORING

The actors of the four OMVG member countries will ensure monitoring. These actors will consist

of the Ministries in charge of the Environment, research institutions, local collectivities, NGOs,

community-based organizations that will monitor the field. These actors are supported by partners

such as OMVG, Wetlands International Africa and other NGOs.

PARTNERS

ORGANIZATION FOR THE DEVELOPMENT OF THE GAMBIA RIVER (OMVG)

WETLANDS INTERNATIONAL

International Union for the Conservation of Nature (IUCN)

ACTORS

GAMBIA

National Environmental Agency (NEA),


Ministry of Natural Resources and Environment

Department of Water Resources

Department of Lands and Surveys

Soils and Water Management Unit

Universities and research institutions

Local collectivities

African Union, FAO, GEF and USAID Office for the international coordination of the Fouta

Djallon

The Green Gambia (Gambia)

NGOs and actors from the civil society

GUINEA

MINISTRY OF ENVIRONMENT

UNIVERSITIES AND RESEARCH INSTITUTIONS

LOCAL COLLECTIVITIES

NGOs and structures working in the environment SECTOR

GUINEA-BISSAU

MINISTRY OF ENVIRONMENT

MINISTRY OF NATURAL RESOURCES AND ENERGY


NGOS AND STRUCTURES WORKING IN THE ENVIRONMENT SECTOR

Local Collectivities

SENEGAL

Ministry of Environment, protection of nature, artificial lakes and retention basins


LOCAL COLLECTIVITIES

NGOS AND STRUCTURES WORKING IN THE ENVIRONMENT SECTOR


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VADEN BERGHEN C. (1988 - 1991). - Flore Illustrée du Sénégal, Tom. IX & X. Gouvernement du

Sénégal, Ministère du Développement Rural, Direction des Eaux et Forêts

VON MAYDELL H.- J. (1992). - Arbres et Arbustes du Sahel: Leurs caractéristiques et leurs utilisation. Gtz

531 p.


Wetlands International. Base de données du Dénombrement des Oiseaux d’Eau en Afrique (DOEA) 2001-

2009

White, F. 1986. La végétation de l’Afrique, ORSTOM – UNESCO, 384p.

www.emanrese.ca

ANNEXES

ANNEXES

Annexe 1 : Proposed list of crabs to be monitored

Species Selection criteria Habitat

Potamonautes ecorssei

Less common Species Main river bed, streams and permanent ponds.

Liberonautus latidactylus

Common species Main river bed, streams and permanent ponds.

Annexe 2: Proposed list of mollusks to be monitored

Species Selection criteria Habitats

Coelatura aegyptiaca Common Species but threatened

In sand or vase bottom between the pebbles or stones

Mutela dubia dubia Common Species but threatened

Running water

Aspatharia dahomeyensis.

Common species in the basin but threatened

Running water

Pleidon ovatus Present in the region Unknown ecology

Corbicula fluminalis Fairly common species but threatened

sandy and mud-sandy bottom

Bellamya unicolor Very common species in the Gambia

Bottom, sediment scraps of papyrus rhizomes, on the banks or on aquatic plants.


Etheria elliptica Rarely Stony or rocky bottom and on rocky beaches of certain lakes in Africa

Annexe 3: Proposed list of odonata to be monitored

Species Selection criteria Habitat

Lestes dissimulans Common species

Swamps, ponds, marshes with herbaceous vegetation, calm streams

Lestes ochraceus Common species

Open ponds and slow streams.

Lestes tridens Common species

Streams, on the lakes’ edges

Chlorocnemis rossii Common species but not evaluated Rivers located at an altitude of 450 to 500

meters, in forest and savannah.

Elattoneura nigra Common species

Streams and rivers, in wooded areas.

Elattoneura pluotae Species not evaluated but might be endemic in West Africa

Shaded streams

Mesocnemis dupuyi Species not evaluated but might be endemic in West Africa

Rivers, in savannah

Mesocnemis singularis Common species

Rivers, streams and lakes, in savannah or forest

Platycnemis sikassoensis Common species

Rivers not covered, in forests.

Africallagma subtile Common species

Streams, ponds, swamp rivers

Agriocnemis exilis Common species

Swamps, ponds, swamp rivers

Agriocnemis maclachlani Common species Swamp forests.

Agriocnemis victoria Common species Swamps.

Agriocnemis zerafica Common species Swamps and ponds in arid areas.

Ceriagrion bakeri Common species Ponds in dry areas


Ceriagrion corallinum Common species

Swamps in or near a forest.

Ceriagrion moorei Common species

Ponds and streams, in open savannah.

Ceriagrion suave Common species

Ponds and streams, in open and dry savannah.

Ceriagrion whellani Common species

Swamp areas

Pseudagrion camerunense Common species

Rivers in open environments

Pseudagrion epiphonematicum Not evaluated but in a restricted range Along water streams covered in dense forest

Pseudagrion glaucescens Common species Streams and rivers, in savannah

Pseudagrion hamoni Common species Streams and rivers, in savannah

Pseudagrion kersteni Common species

Streams and troubled rivers in different habitats, below 1,800 m.

Pseudagrion massaicum Common species

Streams and rivers, in forest.

Pseudagrion melanicterum Common species

Streams, in forest.

Pseudagrion nubicum Common species

Lakes and swamp rivers where reeds grow.

Pseudagrion sjoestedti Common species

Ponds, streams and rivers, in forest.

Pseudagrion sublacteum Common species

Streams and rivers.

Pseudagrion sudanicum Common species

Open rivers, in forest.

Pseudagrion torridum Common species

On the edges of lakes with reeds.

Phaon iridipennis Common species

Streams and rivers with gallery forests, in savannah.

Sapho ciliata Not evaluated

Mid water streams located on foothills


Sapho fumosa Not evaluated

Water streams in forest, often in mountain.

Umma infumosa Not evaluated

Along water streams, from the foothills to the edge of the forest around 1200 m.

Chlorocypha dispar Not evaluated

From the foothills up to 950 m, seems to show cast a plastic ecology.

Anax tristis Common species

Ponds and rivers, in open environments.

Heliaeschna fuliginosa Common species

Open rivers, in forest.

Crenigomphus renei Common species

Lakes and slow-flowing rivers, in savannah.

Neurogomphus featheri Common species

Forests and savannahs.

Idomacromia lieftincki Not evaluated

Fast streams and rivulets flowing from the foothills, around 500 m, found in Dindéfello (Legrand, 2003).

Phyllomacromia africana Common species

Rivers, forests or woodlands.

Phyllomacromia pseudafricana Common species

Rivers, in the bush.

Acisoma trifidum Common species

Streams, in forest.

Aethiothemis palustris Common species

Information not available

Aethiothemis solitaria Common species

Swamps with reeds

Aethriamanta rezia Common species

Ponds, streams and rivers with slow currents, edges of lakes with dense aquatic vegetation.

Brachythemis lacustris Common species

Streams and rivers, savannahs and woodlands.


Bradinopyga strachani Common species

Pond on armor, in an open habitat.

Chalcostephia flavifrons Common species

Swamps in savanna.

Crocothemis divisa Common species

Ponds, streams and rivers in forest areas

Diplacodes lefebvrei Common species

Cleared swamp habitats.

Diplacodes luminans Common species

Often seasonal swamps, in savannah.

Hadrothemis defecta Common species

Damp forest

Hemistigma albipuncta Common species

Swamps, in savanna and woodland or forest.

Olpogastra lugubris Common species

Cleared rivers but also streams and lakes.

Orthetrum angustiventre Common species

Woodland and forest galleries.

Orthetrum brachialis Common species

Swamps, savannahs and woodlands.

Orthetrum guineense Common species

Cleared streams

Orthetrum hintzi Common species

Ponds and streams, in savannahs and woodlands or forests.

Orthetrum icteromelas Common species

Swamps, streams and forested floodplains.

Orthetrum Julia Common species Streams, in forest.

Orthetrum microstigma Common species Streams, in forest.

Orthetrum monardi Common species

Swamp forests.

Orthetrum stemmalis Common species

Ponds and swamps, in forest.

Oxythemis phoenicosceles Common species

Ponds of damp forests, floodplains, swamps.

Palpopleura lucia Common species

Swamp habitats, in savannah and forest.

Palpopleura Portia Common species

Swamps in savannah and woodland.


Parazyxomma flavicans Common species

Stagnant water, in/near a forest.

Rhyothemis notata Common species

Streams, in forest.

Tetrathemis camerunensis Common species

Ponds and streams with slow currents, in damp forest.

Trithemis dichroa Common species

Ponds and streams, in forest.

Trithemis grouti Common species

Streams, in forest.

Trithemis hecate Common species

Swamps, streams with slow current, in savannah and woodlands.

Trithemis monardi Common species

Swamp ponds and rivers, in woodlands.

Trithemis nuptialis Common species

Streams, in forest.

Trithetrum navasi Common species

Swamps

Urothemis assignata Common species

Ponds, lakes or streams with slow current and rivers, in savannah, in woodlands.

Urothemis edwardsi Common species

Ponds, lakes, floodplains or streams with slow current, savannah and woodlands.

Annexe 4: Proposed list of birds to be monitored


Amaurornis flavirostra Less common species Swamps

Haematopus ostralegus Migratory Palaerarctic

Less common

On the coast

Philomachus pugnax Migratory Palaerarctic

Common

Swamps and rice fields

Gallinago gallinago Migratory Palaerarctic

Common to less common

Swamp areas


Limosa limosa Migratory Palaerarctic

Common

Rice fields or freshwater swamps

Phoenicopterus minor Less common Lakes

Ciconia nigra Migratory Palaerarctic

Less common

Delta

Ardea purpurea Migratory Palaerarctic

Common

Delta

Leptoptilos crumeniferus Rare On land

Nests on trees

Ephippiorhynchus senegalensis

Rare Delta

Nests on trees

Annexe 5: Proposed list of plants to be monitored


Acroceras amplectens Common species Permanent or temporary shallow waters

Swamps, rice fields, lakes and rivers

Aeschynomene afrspera Common species Waters deep enough, rice fields, eutrophic environments

Aeschynomene crassicaulis Common species Waters deep enough, rice fields, eutrophic environments, participates in floating rafts

Aeschynomene elaphroxylon Common species and participates in floating rafts

Waters deep enough, rice fields, eutrophic environments

Aeschynomene tambacoundensis Endemic in West Africa Deep enough waters, rice fields, eutrophic environments

Aldovanda vesiculosa Rate species Calm and clear waters, oligotrophic, permanent and deep enough


Aponogeton subconjugatus Endemic in West Africa Ponds not very deep that have been flooded for a long period, muddy

Areas flooded by the river

Azolla africana Proliferous species Ponds, temporary rivers arms, often temporary muddy waters

Bergia capensis Common species Often muddy ponds, waters more or less temporary, euthrophic, rice fields

Bolboschoenus grandispicus Vulnerable species Flooded depressions on the coast

Caperonia sengalensis Vulnerable species Flooded ponds, ricefields

Ceratophyllum demersum Vulnerable species Calm, deep, permanent waters ; mostly eutrophic environments

Ceratophyllum submersum Vulnerable species Calm, deep, permanent waters ; mostly eutrophic environments

Cyperus latericus Endemic, rare and endangered in Senegal

Relatively important settlements along borders of ponds on a lateritic slab

Echinochloa colona Common species Permanent or temporary waters

Echinochloa stagnina Common species Permanent or temporary waters

Eichhornia natans Common species Moderately deep, or /almost permanent clear waters ;

Ponds, lakes, streams, rice fields

Eleocharis deightonii Endemic in West Africa Flooded rice fields or recently dewatered swamps

Eriocaulon meklei Endemic in West Africa Temporarily flooded marshes ; swamps

Floscopa axillaris Endemic in West Africa Shallow, permanent or temporary waters ; swamps, rice fields

Heliotropium indicum Common species

Hygrophila africana Common species Temporary ponds

Hygrophila barbata Endemic in West Africa Swamp meadows, rice fields

Hygrophila niokoloensis Rare species??

Hygrophila odora Endemic in West Africa On the borders of water, in particular on the Gambia river

Hygrophila senegalensis Endemic in West Africa Swamp meadows

Ipomea aquatica Common species Swamps, humid locations


Isoetes melanotheca Endemic in West Africa Swamps

Ledernaniella abbayesii Endemis in Guinea Humid rocks

Leersia hexandra Common species Swamp depressions, along borders of ponds

Lemna aequinioctalis Common species Watercourse, lake

Ludwigia adcendens Common species and participates in the floating rafts

Ponds, flooding areas, calm rivers, often muddy temporary waters ;

Usually eutrophic environments, slightly brackish and oligotrophic

Ludwigia leptocarpa Common species and participates in the floating rafts

Flooded areas, drained sands, along lakes, swamps

Monochoria brevipetiolata Common and endemic to West Africa

Temporary ponds on rocks or bowé

Najas welwitschii Endemic, rare and endangered in Senegal

Clear waters on bowé or rocks, temporary muddy ponds, rice fields

Neseae crassicaulis Common species Flooded ponds, shallow, temporary and often muddy waters

Ditches, rice fields

Nymhoides guineense Common and maybe endemic in West Africa

Oligotrophic ponds on rocks

Nymphaea lotus Common species Eutrophic muddy ponds

Nymphaea micrantha Common species Eutrophic muddy ponds

Nymphoides indica Common species Rice fields

Oryza barthii Common species Watered ditches, ponds and flooded soils

Oryza longistaminata Common species Stagnant waters

Panicum anabaptistum Common species Flooded plains, watercourse banks and beds

Phragmites australis Proliferous species Ponds, torrent beds

Pistia stratiotes Proliferous species Ponds, watercourse bays

Polygonum seneglense Common species Permanent wonders, eutrophic environments, ponds, ditches, rice fields

Potamogeton octandrus Proliferous species Permanent deep waters, lakes, calm streams

Potamogeton schweinfurthii Proliferous species Permanent deep waters, lakes, calm streams


Pycreus mundtii Common species Muddy waters or with slow current

Raphia palma-pinus Species likely endemic in West Africa

Swampy thickets

Raphia sudanica Likely endemic in West Africa

Swamps, near water points

Rhynchospora corymbosa Common species Swamps, near fresh water, flooded rice fields

Rotala stagnina Rare species More or less temporary ponds on sands, rocks or bowé, streams

Clear shallow waters

Rotala tenella Rare species More or less temporary ponds on sands, rocks or bowé, streams

Clear shallow waters

Rytachne furtiva Endemic in the sub-region and vulnerable

Floodplains

Sphenoclea dalzielii Likely endemic in West Africa

River flood areas or rice fields

Thalia welwitschii Common species Swamps

Typha domingensis Proliferative species Water courses, ponds, lakes

Utricularia inflexa Common species Calm waters ; floodplains

Utricularia reflexa Common species Calm waters ; floodplains

Vetivera nigritana Common species Flooding areas

Vossia cuspidate Common species Temporary calm waters, sometimes profound

Ziziphus spina-christi Common species Near rivers with strong flooding

Wolffia arrhiza Stagnant fresh waters, eutrophic ponds sometimes almost brackish sometimes

Annexe 6 : Additional List of plants

1. Mimosa pigra ;

2. Mitragyna inermis ;

3. Mimosa pudica (invasive exotic)

4. Stylosenthes sp. (used by antelopes for food purposes);

5. Nelsonia canencens (fertility indicator?);


6. Borrasus aethiopum (great economic value and endangered);

7. Elaeis guineensis (great economic value and endangered) ;

8. Alchornea cordifolia (water retention);

9. Centella asiatica ;

10. Guiera senegalensis (dryness indicator status);

11. Calotropis procera (dryness indicator status);

12. Pandanus candelabrum (depletion);

13. Carapa procera (depletion);

14. Dialium guineensis (depletion);

15. Pseudospondias microcarpa (depletion);

16. Euphorbia sudanica (depletion)

17. Sapium ellipticum (depletion);

18. Spondias mombin (Endangered: Guinea monograph);

19. Syzygium guineense (depletion);

20. Uapaca heudelotii (depletion);

21. Xylopia aethiopica ;

Annexe 7: Proposed list of fish to be monitored


Lates niloticus Common species but not evaluated, unlisted

Sandy, rocky and muddy bottoms Vegetation zones Calm, stagnant or current waters Channel, lakes and irrigation channels

Hyperopisus bebe bebe Common species but not evaluated, unlisted

Demersal species living exclusively in freshwater under a tropical climate

Schilbe micropogon Endemic species of West Africa’s coastal basins

Demersal species living exclusively in freshwater under a tropical climate

Schilbe mystus Common species but classified as vulnerable because of excessive exploitation

Stagnant deep waters, shallow marshes and occasionally in shallow floodplains.

Hemichromis fasciatus Common species but not evaluated, unlisted

Benthopelagic freshwater species. It is found in the hyperhialine estuaries in Sine-Saloum and Casamance

Citharinus citharus citharus

Endemic species of the Sudanian region but not evaluated, unlisted

Demersal anadromous species living under a tropical climate

Synodontis gambiensis Common endemic species of West Africa but not

Benthopelagic freshwater species that lives under a tropical climate and that can be found in a shallow


evaluated, unlisted sheltered environment

Barbus dialonensis Common endemic species of the West African region but not evaluated, unlisted

Benthopelagic species

Barbus salessei Common endemic species of the West African region but not evaluated, unlisted


Clarias anguillaris Common species but endangered by excessive fishing

Benthic habitats

Heterotis niloticus Common species in the Gambia basin

Calm areas of large rivers, open lake and river waters

Barbus niokoloensis Endemic species of the West African region


Annexe 8 : Additional list:

Saretheroalon galileus

Heterobranchus longifilus

Malapterivus electricus

Labeo senegalensis

Mugil falciparum.

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