Methodology

The methodology for identification and delineation of global freshwater KBAs in western Africa followed the new Global Standard for identification of Key Biodiversity Areas (IUCN, 2016). Here we briefly describe the KBA criteria and thresholds (section 9.2.1), and then go on to describe how these were applied to validate the CEPF freshwater KBAs in western Africa (section 9.2.2), first through desktop analysis (section 9.2.2.1) and then followed by stakeholder consultation workshops (section 9.2.2.2).

9.2.1 KBA criteria and thresholds

The criteria set out in the Global KBA Standard (IUCN, 2016) provide quantitative thresholds for identifying sites that contribute significantly to the global persistence of biodiversity (Table 9.1). The high level criteria are designed to capture sites of importance for: A) threatened biodiversity; B) geographically restricted biodiversity; C) ecological integrity;

D) biological processes; and E) irreplaceability through quantitative analysis. Sites identified as potential KBAs should ideally be assessed against all criteria. Although not

Table 9.1 Summary of the KBA A and B criteria and thresholds, modified after IUCN (2016).

KBA criterion Biodiversity element at site % global population.

Size/extent RU

A. Threatened biodiversity

A1. Threatened species

(a) CR or EN species ≥0.5% ≥5

(b) VU species ≥1% ≥10

(c) CR or EN species threatened only due to population size

reduction in the past or present ≥0.1% ≥5

(d) VU species threatened only due to population size reduction

in the past or present ≥0.2% ≥10

(e) CR or EN species Entire global population

size

B. Geographically restricted biodiversity

B1. Individual geographically

restricted species Any species ≥10% ≥10

B2. Co-occurring geographically

restricted species Restricted-range species: ≥2 species OR 0.02% of global

number of species in the taxonomic group, whichever is larger ≥1% –

B3. Geographically restricted assemblages

(a) Within a taxonomic group, ≥5 ecoregion-restricted species OR 10% of the species restricted to the ecoregion, whichever

is larger ≥0.5% –

(b) ≥5 restricted species OR 30% of the bioregion-restricted species known from the country, whichever is larger,

within a taxonomic group – –

(c) Part of the globally most important 5% of occupied habitat of

each of ≥5 species within a taxonomic group – –

all these criteria are applicable or relevant for the freshwater taxonomic groups considered at the workshop (e.g. not all taxonomic groups have species that aggregate), meeting any one of the criteria (or sub-criteria) is enough for a site to be considered for qualification as a KBA. Species meeting the KBA thresholds and criteria are defined as KBA trigger species. KBA criteria C, D and E were not utilised here due to a lack of suitable data. The criteria and thresholds employed in this project are summarised in Table 9.1.

In addition to these technical criteria and thresholds, the Global KBA Standard specifies that KBAs must be

‘potentially manageable’ units. They can be delineated so as to ‘adopt’ existing management units such as protected areas or community conserved areas, or else to take account of legal and customary land tenures. Furthermore, KBAs cannot overlap one another. When a new KBA is identified which would overlap with another existing KBA, the new KBA proposers have three options:

a) Adopt the existing KBA boundary

b) Propose an adjacent KBA which does not overlap the existing KBA

c) Propose an extension to the existing KBA boundary, to incorporate the new biodiversity element

Preferred

Figure 9.1 Schematic diagram of KBA Proposal process, modified after KBA Secretariat (2019).

In all cases, it is recommended to inform the existing KBA proposers of the new biodiversity element, and consultation is required before making any modifications to existing KBA boundaries (option c).

9.2.2 Freshwater KBA validation

There are 13 freshwater KBAs proposed in the Guinean Forests of West Africa (GFWA) Ecosystem Profile (CEPF, 2015), spanning a range of countries in the Upper Guinean Forests and Lower Guinean Forests. These sites were identified through the Ecosystem Profile as being the most critical sites for freshwater biodiversity within the GFWA Biodiversity Hotspot. These sites were identified prior to publication of the KBA Global Standard (IUCN, 2016), delineated according to large river basins, and are not considered to be ‘manageable’

sites. Here we re-assess these sites against the KBA Global Standard. We first used the updated Red List assessments, discussed in Chapters 3–7, in a desktop analysis to screen the CEPF freshwater KBAs and other potential sites in western Africa against KBA criterion A on threatened biodiversity, and criterion B on geographically restricted biodiversity. We then convened stakeholder consultation workshops in six countries to assess the potential manageability and delineation of these sites with respect to local and national laws, jurisdictions and other designated areas such as existing protected areas and KBAs.

9.2.2.1 Desktop analysis

A desktop analysis was conducted using data collated through IUCN Red List assessments for the following freshwater taxonomic groups: i) fishes, ii) molluscs; iii) odonates (dragonflies and damselflies); iv) crabs and shrimps, and; v) aquatic plants (Chapters 3–7). The datasets collected include the required information on species ranges and their IUCN Red List Categories of extinction risk as published on the IUCN Red List. The steps in the analysis are as follows:

a. Assemble spatial data sets of:

i) Species Red List distribution maps for freshwater fishes, molluscs, odonates, crabs and crayfish, and aquatic plants;

ii) Boundaries of existing KBAs and Protected Areas.

It should be noted that KBA delineation is an iterative process leading to revision and updating of existing KBAs as appropriate through use of better and more recent data, as they become available (IUCN, 2016). The species Red List Assessments employed here were completed in 2018–2020 through the first component of the project (see Chapters 2–7), to ensure that data are traceable to a reliable source and sufficiently recent (and updated) to give confidence for confirming whether biodiversity elements are still present at the sites.

b. Derive proposed site boundaries based on biological data. Using the species distribution maps assembled in Stage 1a above, all river/lake sub-catchments in western Africa that contain potential KBA trigger species were identified based on intersections of sub-catchments with species’ mapped ranges. River/lake sub-catchments were delineated according to the spatial data layer called HydroBASINS (Lehner & Grill, 2013) (see Chapter 2). The resolution used for selecting sub-catchments holding KBA trigger species was HydroBASINS Level 8, which in western Africa delineates sub-catchments with a median area of 352 km², including lakes. In this way, maps were created to show the numbers of potential trigger species per sub-catchment. Lists of potential trigger species thought to be present in each sub-catchment were also compiled. This process was achieved through a screening of all sub-catchments against the full complement of species maps using an R script (R Core Team, 2020) developed by Konstantina Spiliopoulou (Spiliopoulou, 2021) to identify the trigger species present and the criteria triggered for each sub-catchment (Figure 9.2).

During the analysis those sites that potentially qualified as AZE sites were also identified. AZEs sites are places that contain the last or only populations of globally Critically Endangered or Endangered species almost entirely restricted to that single remaining site (Ricketts et al.,

2005). The AZE map can be accessed at https://www.

zeroextinction.org/.

9.2.2.2 Validation and delineation workshops Workshops were convened to identify and delineate KBAs in each of the six countries containing freshwater KBAs in the CEPF GFWA Ecosystem Profile (CEPF, 2015). These workshops were convened by IUCN in the first quarter of 2021. Each of the workshops took place physically within each respective country, with the IUCN Global Species Programme providing KBA training via remote video link to avoid international travel during the global coronavirus pandemic. IUCN also presented the potential KBAs, as derived from the Stage 1 desktop analysis, for validation.

The workshops in Sierra Leone, Liberia, Côte d’Ivoire, Ghana and Nigeria were facilitated by the BirdLife Partner in each country, respectively. In Cameroon, the workshop was facilitated by IUCN West and Central Africa Regional Office.

The workshops convened stakeholders from various sectors including local and national government, civil society and the private sector. The aim of the workshops was to validate the 13 freshwater KBAs presented in the CEPF Ecosystem Profile and to identify and validate any other potential KBAs emerging from the desktop analysis and to delineate site boundaries which are ecologically relevant and practical

Figure 9.2 Number of potential KBA trigger species per sub-catchment, based on threat status, taxonomic classification and range intersection. Source: Compiled by the report authors using data from the IUCN Red List (2021).

Figure 9.3 Sub-catchments potentially yielding AZE sites based on range intersection. Source: Compiled by the report authors using data from the IUCN Red List (2021).

for management (IUCN, 2016). Workshop participants were asked to delineate KBA boundaries according to the following procedure:

a. Confirmation of KBA trigger species’ presence within sub-catchments

b. Delineation of potential new KBAs boundaries:

i. with respect to pre-existing KBAs ii. with respect to Protected Areas

iii. for KBAs with no overlap with other KBAs or Protected Areas

c. Complete the minimum documentation requirements for each KBA

A significant outcome of these workshops was to raise awareness about the most important sites for freshwater biodiversity in western Africa. Many of the workshop participants will be involved in national spatial conservation prioritisation and policy, as well as the re-assessment of existing KBAs and identification of new KBAs in western Africa.