INVESTIGADORES
CASTELLARINI Fabiana De Lujan
artículos
Título:
Towards an optimal sampling strategy to assess groundwater biodiversity: comparison across six European regions
Autor/es:
DOLE-OLIVIER, M-J.; CASTELLARINI, F.; COINEAU, N.; GALASSI, D.; MARTIN, P.; VALDECASAS, A.; GIBERT, J.
Revista:
FRESHWATER BIOLOGY (PRINT)
Editorial:
Blackwell
Referencias:
Año: 2009 vol. 54 p. 777 - 796
ISSN:
0046-5070
Resumen:
1. Reliable assessments of groundwater biodiversity are urgently needed to resolve
current issues relating to the protection of aquifers. The assessment of groundwater
biodiversity is hampered by the physical complexity and difficult access to the
subterranean environment, which is related to the vastness, high degree of fragmentation
and environmental heterogeneity of groundwater systems. Knowledge on groundwater
biodiversity is also biased towards penetrable karstic habitats (caves), whereas other
common habitats such as those found in porous aquifers have been neglected. This
situation calls for a standardised and comprehensive strategy to sample an exhaustive and
balanced set of groundwater habitats.
2. A standardised sampling protocol aimed at capturing the main sources of environmental
heterogeneity within regions was applied in six regions across Europe. Four
hierarchical levels were considered: (i) region (c. 400 km2); (ii) basin (c. 100 km2); (iii)
aquifer type (karstic or porous) and (iv) habitat (hyporheic and phreatic zones for porous
aquifers; saturated and unsaturated zones for karst aquifers). A total of 192 sampling sites
equally distributed among habitats were sampled within each region.
3. Stygobiotic species richness significantly varied across regions, probably as a result of
important difference in physical and biogeographical characteristics among the regions.
Only one species (Graeteriella unisetigera) occurred in all six regions, underlining the
narrow geographic range and high degree of endemism of stygobiotic fauna. The low
frequency of occurrence of stygobionts also points to the importance of rarity in ground
waters and its relevance for drawing up sampling designs.
4. Rarefaction curves were calculated to determine sampling efficiencies within each
region. Despite the high sampling effort, the curves did not reach saturation, especially in
the Cantabria, Lessinia and Krim regions, which had the greatest numbers of rare species.
5. Species accumulation curves were also calculated by considering the main sources of
environmental heterogeneity among basins, aquifer types and habitats captured by the
sampling protocol. In two regions (Roussillon and Jura) sampling efficiency was improved