Several approaches for defining hotspots have been developed by conservation organisations, like Key Biodiversity Areas, Important Bird Areas, Critical Sites, Freshwater Ecoregions, etc. Many of these concepts are based on roughly similar criteria for delineating hotspots:
- A hotspot should contain a minimal proportion of the global, regional or flyway population;
- Attention for areas where (groups of) species aggregate during stages of their lifecycles;
- Additional focus on range-restricted species;
- The incorporation of threats for identification of hotspots. However, there is a distinction whether these treats are perceived from a species level (IUCN Red List) or from a threat to the area as such resulting from i.e. conversion of land, land-use, urbanisation, surface water abstraction.
These approaches assume a reasonable amount of detailed information on the distribution and abundance of species. Important Bird Ares and Critical Sites Networks focus on bird species, but the other approaches also consider other taxa. Key Biodiversity Areas look at all relevant taxa.
Defining ecological hotspots in the Upper Niger Basin
In contrast to the Inner Niger Delta (see below), detailed ecological data for the Upper Niger Basin are scarce. The starting point for delineating hotspots in the UNB is the work of Brugiere & Kormos (2008) on Key Biodiversity Areas (KBAs) in Guinea. In addition, several other categories of ecological hotspots are used, including Important Bird Areas from BirdLife International and Critical Sites from Wings over Wetlands. The classification of ecological hotspots within the UNB is based on four main criteria:
- Identifying Key Biodiversity Areas
Starting point is the analysis of Bugiere & Kormos (2008) and the KBAs they identified in Guinea within the boundaries of the UNB. Using their approach based on threatened mammals this will be extended into the Malian part of the UNB. As far is relevant, these areas are completed with the KBAs delineated by IUCN (2016) and Important Bird Areas.
- Critical sites (WOW)
Based on other bird surveys (Critical Sites, Wings over Wetlands) the list of key areas is completed with data for threatened and endemic birds species, as well as known bird concentrations within the UNB, using a scoring method comparable with the one used by Brugiere & Kormos (2008). By doing so, KBAs from step I are completed with sites with a high score on bird diversity.
- Important Biodiversity areas for fish communities/species
Fish data are probably the least detailed and good data are scarcely available, as most surveys cover only small parts of the area. Some information can be used from the (proposed) Ramsar sites.
- Areas with a high biodiversity in the region based on Protected Areas
Where appropriate the list of key areas is expanded with data from the Protected Area network in Mali and Guinea. These areas may harbour high biodiversity values in the region or subregion (for example, breeding colonies or populations of vulnerable species).
Defining ecological hotspots in the Inner Niger Delta
From several studies it is clear that the entire IND can be regarded as an ecological hotspot harbouring outstanding biodiversity and significant parts of globally threatened water bird populations. For this reason the floodplain area has been designated as a Ramsar site in 2004. Within the BAMGIRE programme, new information on vulnerable sites and key areas is used to define hotspots within the delta. This does not imply that areas which are not selected as key sites, are not ecologically important or part of the ecological hotspot. The vulnerable sites and key areas are identified to prioritise and stimulate an effective management of the area as a whole. This information could be used to enforce the protection of specific sites or species in the area, given that the IND to date has not been assigned as legal protected area.
The classification of vulnerable sites and key areas within the IND is based on four main criteria:
- Key Habitats in the floodplain ecosystem
Some habitats in the IND play a key role in the ecosystem and are vital to preserve the biodiversity and to sustain the production of natural resources (for instance breeding zones for fish). This applies for instance to flood forests, moist forest around the delta, bourgou fields, mares, permanent deep water, shallow lakes etc.
- Water Bird Concentrations
Based on data from monitoring of water birds, areas and sites will be selected that hold large concentrations of water birds. This applies to roosts of water birds, large concentrations of foraging water birds and sites with a high densities of rare species.
- Breeding Colonies
The IND holds a number of major breeding colonies of herons, ibises and cormorants, which are amongst the largest in Africa. In addition, there are sites where rare species come to breed, such as the vulnerable Black Crowned Crane.
- Areas with a high biodiversity of threatened species
Areas that harbour threatened or range-restricted species like Hippos, Manatees etc, or which are vital for these species during certain stages in their life cycle.