ESG RISK 6: Biodiversity and Habitat Connectivity
Overview
ESG Risk 6 - Biodiversity and Habitat Connectivity focuses on risks in hydropower projects that stem from physical habitat changes, fragmentation, and disruptions to aquatic and terrestrial ecosystems. Impacts extend beyond the project footprint to upstream and downstream areas, including associated infrastructure. Projects in or near protected areas and critical habitats pose particularly high risks. Hydropower can affect terrestrial species movement, river system connectivity, and ecosystem services, with significant concerns related to species migration, genetic diversity, and habitat loss. Extreme risk scores may trigger strong NGO opposition, lack of industry support, costly mitigation, and severe socio-economic impacts, particularly for communities reliant on affected ecosystems.
Additional Guidance
The following are some important concepts regarding ESG Risk 6 - Biodiversity and Habitat Connectivity.
A habitat is the place or type of site where an organism or population naturally occurs. The major terrestrial habitat change due to a hydropower project is loss of terrestrial habitat, due to construction disturbances, operation stage built areas, and flooding of land from creation of an impoundment. The major aquatic habitat changes are the conversion of flowing water (a“lotic” ecosystem) to still water (a “lentic” ecosystem) by creation of the impoundment; and changes to the downstream hydrology (for projects other than true run-of-river). Physical changes will cause changes to biodiversity where there are dependencies on those habitats.
Critical habitats include important avian areas; areas that provide growth, cover, food, breeding sites, and areas protected from disturbances for migratory and riverine fish species hotspots of endemism; habitats for threatened species, etc. Areas of habitat may be identified as critical if they are crucial to the survival of, and support recovery of, species listed as threatened.
An endemic species is an organism that is native to one particular geographic locality, and not found elsewhere. A restricted range species has a geographically-restricted area of distribution.
Threatened species are those species included in the Critically Endangered (CR), Endangered (EN) or Vulnerable (VU) categories of the International Union for Conservation of Nature (IUCN) Red List . The IUCN Red List of Threatened Species is a comprehensive inventory of the global conservation status of plant and animal species, recognised as the most authoritative guide to the status of biological diversity due to its strong scientific base. It uses a set of quantitative criteria to evaluate the extinction risk of thousands of species. These criteria are relevant to most species and all regions of the world.
In addition to obtaining a global perspective, it is important to recognise that a species can also be threatened locally, often due to habitat losses from land uses and local activities.
Key Biodiversity Areas (KBAs) are those sites contributing significantly to the global persistence of biodiversity in terrestrial, freshwater and marine ecosystems. The key function of KBAs is to highlight areas that are not yet protected. Ramsar sites are an example of KBAs. Ramsar sites are wetlands of international importance that have been officially designated under the criteria of the Ramsar Convention on Wetlands for containing representative, rare or unique wetland types, or for their importance in conserving biological diversity.
Protected areas must be managed to protect and maintain biological diversity according to one of the six international classes developed by the IUCN. Classes vary according to their management objectives, which range from strict nature conservation to multi-use reserves. Importantly, protected areas can be threatened by a project even if not located in the area of direct impact.
A concept related to protected areas is “Other Effective Area-based Conservation Measure”, or OECM, which is a phrase that first appeared in the 2010 Convention on Biological Diversity (CBD). An OECM is a geographically-defined area other than a Protected Area that achieves long-term conservation of biodiversity. These areas are managed to deliver positive and sustained outcomes for in-situ conservation of biodiversity and its associated ecosystem functions and services. Examples of OECMs include sacred natural sites managed by Indigenous Peoples, areas designated for sustainable forestry, and agricultural landscapes that support wildlife conservation. OECMs can complement traditional protected areas by conserving ecosystems, habitats, and species in places where formal protection may not be feasible.
The location of the dam is a major factor in the degree of fragmentation created by a hydropower project. Strategic hydropower planning tools such as ‘Hydropower by Design’ can help assess potential project configurations that will have the lowest impacts on river connectivity in a river basin. While impacts to all riverine fish and other aquatic organisms should be considered, impacts to connectivity of migratory fish species are especially of high concern, most particularly in the case of migratory fish relying on full access to the river to complete their life cycle. Risks are greatly heightened where aquatic connectivity impacts affect species that are important for peoples’ food security.Mitigating hydropower’s impact on upstream and downstream connectivity can be achieved through a number of measures, which have variable levels of efficacy. These measures might include nature-like fishways, exclusion screening and bypass routes, fish ladders, fish elevators, trap and transport programs, and turbine designs that enable safe through-turbine fish passage. It is important to acknowledge that all hydropower sites are unique – mitigation strategies that work at one site may not solve passage issues at a site with different characteristics or different fish species. Design features assisting aquatic species passage (and sediment through-flow, see ESG Risk 3) at a minimum need to be carefully researched, properly designed, and operated for the specific project, and incorporate monitoring and evaluation programs to assess their effectiveness.
Off-site mitigation offsets such as removing an existing dam or weir that presently causes high impacts to river system fragmentation can be another useful measure to consider to support habitat and species recovery. Offset measures can support fish populations but should not be considered as a substitute for direct mitigation that preserves connectivity for migratory fish at the project site.
Sources of information that can help inform ratings for ESG Risk 6 - Biodiversity and Habitat Connectivity include:
HSA How-to Guide for Biodiversity and Invasive Species;
The Integrated Biodiversity Assessment Tool (IBAT) identifies areas of biodiversity importance within 1, 10 and 50 km of a site, and provides an inventory of potentially-present species. World Heritage Sites (designated for outstanding universal value) are integrated into IBAT. IBAT can produce a biodiversity data report delivered as a package that includes a pdf document, raw data in CSV format, and map files. Report templates include a simple proximity report, a World Bank Group risk report, and a freshwater report. Initial lists of potential critical habitat triggers generated by IBAT should be used to scope biodiversity surveys, i.e. any particular species or areas for which the most thorough surveys are required;
The Alliance for Zero Extinction (AZE) is a joint initiative of biodiversity conservation organisations from around the world to prevent extinctions by promoting the identification and ensuring safeguarding and effective conservation of key sites that are the last remaining refuges of one or more Endangered or Critically Endangered species;
Further global databases such as the IUCN Red List, and Ramsar wetlands;
The World Database of Protected Areas is the most up to date and complete source of data on protected areas and other effective area-based conservation measures (OECMs);
Topographic map analysis of the terrestrial habitat availability and the existing or potential protected areas in the future reservoir catchment and region;
Topographic map analysis of the river system to calculate the length of river and tributaries affected by the reservoir as well all affected downstream reaches, and calculation of unaffected river reach lengths to determine overall project impact on the river system;
Scientific literature review and consultation with experts regarding important aquatic biota migratory routes and patterns and important riparian habitats.
If needed, users of HydroSelect should review any of the following further sources of online information:
National parks services and environmental agencies may maintain databases and websites with information on biodiversity and critical habitats within their jurisdictions;
The World Wide Fund for Nature (WWF) offers interactive maps and reports on critical habitats worldwide;
International Union for Conservation of Nature (IUCN) provides information on protected areas, key biodiversity areas, and conservation initiatives;
The Global Biodiversity Information Facility (GBIF) provides free and open access to biodiversity data, including species occurrences and distribution maps;
The UN Environment Programme (UNEP) publishes reports and assessments on biodiversity and ecosystems, including the Global Biodiversity Outlook and the Ramsar Convention on Wetlands, and offers information on protected areas, biodiversity hotspots, and ecosystem services;
National mapping agencies in many countries often provide online portals or map services where users can access and download topographic maps, including those showing rivers and tributaries;
Google's mapping services Google Earth and Google Maps offer satellite imagery and terrain views that show terrestrial environments, rivers and tributaries in various parts of the world. While not traditional topographic maps, these platforms provide valuable visualisations of geographical features, including water bodies.
Determining whether an affected habitat is critical is done on a project-by-project basis. Extensive inventories and field studies of aquatic and terrestrial flora and fauna are typically undertaken during the ESIA for a hydropower project.
Opportunities for early stage actions that could reduce the risk for a project option might include:
Alternative locations and designs so the project can avoid any protected area or areas of high biodiversity significance.
Offset (i.e. compensation measure) options for biodiversity impacts, as a last step in applying the mitigation hierarchy for any residual impacts.
Identification of potential opportunities to improve terrestrial and/or aquatic habitat connectivity.
Incorporation of “nature-positive” actions. “Nature positive” means enhancing the resilience of our planet and societies to halt and reverse nature loss.
Example positive actions for biodiversity include:
Habitat restoration efforts, such as involving reforestation, wetland restoration, the creation of artificial habitats to support diverse species, or establishment of wildlife corridors to connect fragmented habitats;
Identifying and protecting critical habitats and species, such as through implementing buffer zones around sensitive areas, relocating species to suitable habitats, and establishing conservation areas to preserve biodiversity;
Incorporating green infrastructure elements, such as green roofs, permeable pavements, and vegetated swales into project designs that can provide habitat for wildlife, improve soil quality, and promote biodiversity;
Including wildlife crossings such as overpasses, underpasses, and culverts to help facilitate the movement of animals across roads and railways, thus reducing the risk of collisions and enhancing connectivity between habitat patches;
Integrating infrastructure planning with land use planning to help identify areas of high ecological value and prioritise their conservation. This can involve zoning regulations, land-use planning tools, and conservation easements to protect important habitats.
Creating new protected areas or increasing the level of protection for existing areas can often be seen as a relatively feasible enhancement for biodiversity conservation and ecosystem preservation. However, there may be more to consider than initially foreseen, for example, the need to:
Undertake thorough assessments to identify areas with high biodiversity value, unique ecosystems, or significant ecological importance in order to identify and make the case for priority areas;
Establish legal protections and institutional frameworks to ensure the effective management and long-term conservation;
Involve local communities, Indigenous Peoples, and other stakeholders in the decision-making processes;
Develop comprehensive management plans that outline conservation objectives, zoning regulations, monitoring protocols, and enforcement mechanisms;
Secure sustainable funding sources for protected area management and robust monitoring programs;
Consider risks, including impacts of climate change.
Effective planning, collaboration, and adaptive management are essential for achieving these goals. Any biodiversity enhancement needs to be very well researched and managed so that quantifiable enhancements in biodiversity parameters (e.g. species diversity, population sizes, genetic variability, overall ecosystem vigor) can later be demonstrated.
