Context of the Project
The Belgium Biodiversity Platform (BBP), the Belgian Science Policy (Belspo) and the Royal Belgium Institute of Natural Sciences (RBINSc, Brussels, Belgium) sponsor the workshop and the publication of the subsequent book.
- The freshwater biodiversity status
Addressing water quantity, quality and availability for human uses is of critical importance but should not live down the major crisis faced by biodiversity and biological resources of inland waters that is directly correlated to water resource integrity (Postel & Richter, 2003). Indeed, biodiversity losses in terms of species and habitat have major consequences on the whole water cycle and lead to increased natural disasters and reduced natural processes of water attenuation and cleansing. In addition to their own intrinsic value, ecosystems also provide essential goods and services to humankind (Postel & Carpenter, 1997) especially in the poor communities traditionally dependent on their natural resources.
Threats to biodiversity of inland waters have long been identified without much success in mitigating their effects (Dudgeon et al., 2005). In the context of the international decade " Water for life " freshwater biodiversity should be the over-riding conservation priority but much stand forth to mobilize medias and policy makers (Dudgeon et al., 2005). One of the critical issues is to provide a global picture of biodiversity in inland waters in order to help define conservation strategies.
Several projects have completed assessments of freshwater biodiversity but focused mainly on leading ' better-known ' groups such as fish, or identified keystone species and/or endemic freshwater systems for conservation purposes. A few global initiatives have gathered available information on biodiversity of inland waters: Groombridge & Jenkins (1998); Groombridge & Jenkins (2000) and Revenga & Kura (2003).
- Project goal
Our purpose is to complete these existing projects by providing an expert assessment of animal (species and generic) diversity in the continental (fresh)waters of the world by focusing on taxonomic and biogeographic diversity. The main three objectives for each group are:
(1) to give the current numbers of known global species and generic diversity;
(2) to identify the known biogeographic distribution (by zoogeographic region), and to stress possible gaps;
(3) to highlight the main areas of endemicity.
Because these extant patterns are the results of historic processes, the project will also emphasize phylogenetic aspects and processes of evolution and speciation. In addition, information on human related issues such as economical and medical uses, threats, conservation issues, are also included when pertinent.
Our assessment includes non-marine aquatic species of inland waters in two categories:
(1) The ' real aquatic species ' accomplish full or part of their lifecycle in or on the water.
(2) The ' water-dependent or paraquatic 'species show close/specific dependence on aquatic habitats (eg., for food or habitat).
For each group, the so-called limno-terrestrial species are not included in the total numbers but they can be discussed in the chapter when pertinent. Regarding interface environments: euryhaline species in estuaries are only included if they show a genuine tolerance to freshwater (< 3 g/l) and only the non-marine fauna is including from Anchialine caves and marine to non-marine interstitial environments.
- Project Activities
A first implementation phase of this project was carried out from September 2002 to June 2003 and led to a first, very approximate, assessment. This assessment was based on existing databases, published reviews and scientific expertise. The objective was to produce a preliminary discussion document that mainly identified gaps in our knowledge and could be used for discussion (Lévêque et al., 2005). These preliminary results give an order of magnitude for known freshwater animal species worldwide of 100 000, half of which are insects. Among other groups, there are some 20 000 vertebrate species; 10 000 crustacean species and 5 000 mollusc species that are either true aquatic or water dependant species.
The preliminary study highlighted gaps in the basic knowledge of species richness at continental and global scales:
(1) Some groups such as freshwater nematods or annelids have been less studied and data on their diversity and distribution is scarce. Because current richness estimates for these groups are greatly biased by knowledge availability, we can expect that real species numbers might be much higher.
(2) Zoogeographic regions are not equal in the face of scientific studies: The neotropical and the oriental regions are especially lacking global estimates of species richness for many groups, even for some usually well-known ones such as molluscs or insects.
A second phase has started in March 2005 and will be completed in 2007. This phase consists in implementing a more complete review of animal diversity in freshwaters. We have invited taxonomic experts to assemble a team of authors and write a draft chapter on the diversity of each animal group. These coordinating authors are invited to participate in a workshop where their data will be presented and discussed. (October 13-16, 2005). The final versions of these chapters have been published as a special issue of the international journal Hydrobiologia and a spin-off in the hardcover series Developments in Hydrobiology (Balian et al. 2008, 595 ).
Dudgeon, D., A. H. Arthington, M. O. Gessner, Z. Kawabata, D. J. Knowler, C. Lévêque, R. J. Naiman, A. Prieur-Richard, D. Soto, M. L. J. Stiassny & C.A. Sullivan, 2006. Freshwater biodiversity: impotance, threats, status and conservation challenges. Biological reviews (in press).
Groombridge, B. & M. Jenkins, 1998. Freshwater Biodiversity: a Preliminary Global Assessment. World Conservation Monitoring Centre, Cambridge, U.K.
Groombridge, B. & M. Jenkins, 2000. Global Biodiversity. Earth's Living Resources in the 21st Century. World Conservation Monitoring Centre, Cambridge, U.K.
Lévêque, C., E. V. Balian, & K. Martens, 2004. An assessment of animal species diversity in continental water systems. Hydrobiologia 542: 1-29.
Postel, S. & S. Carpenter, 1997. Freshwater ecosystem services. In Daily, G. C. (ed), Nature's Services: Societal Dependence on Ecosystem Services. Island Press, Washington D.C., U.S.A.: 195-214.
Postel, S. & B. Richter, 2003. Rivers for Life: Managing Water for People and Nature. Island Press, Washington D.C., U.S.A.
Revenga, C. & Y. Kura, 2003. Status and Trends of Biodiversity of Inland Water Ecosystems. Secretariat of the Convention on Biological Diversity, Montreal, Technical Series 11.