A spatially explicit approach to prioritize protection areas for endangered freshwater mussels

Abstract

In spite of their conservation importance, only a fraction of lakes and streams globally – including their catchments – are currently covered by conservation areas. To identify conservation gaps, assessing the spatial distribution of biodiversity in relation to conservation areas is a promising approach. A gap‐analysis approach was used to evaluate the protection status of the habitats of two endangered freshwater mussel species, Margaritifera margaritifera (Linnaeus, 1758) and Unio crassus (Philipsson, 1788), in the Federal State of Bavaria, Germany. First, ecological niche models (ENMs) were developed for both mussel species based on presence‐only data in order to identify suitable habitats. Second, binary maps of suitable and unsuitable habitats for the species were used to compare different categories of currently protected areas in a gap analysis. The ENMs for M. margaritifera revealed a spatially restricted distribution with good model performance, whereas the spatial distribution of U. crassus was wider and the model performance was weaker. For M. margaritifera, a higher percentage of suitable habitat is already under some sort of protection, whereas for U. crassus only half of the suitable habitats are under protection. The results suggest that suitable habitats of both species are not sufficiently protected. More effective conservation of M. margaritifera and U. crassus requires separate management: increasing the respective protection categories of already protected habitats of M. margaritifera and incorporating an increased area of suitable habitats under legal protection for U. crassus.

Novel insights into habitat suitability for Amazonian freshwater mussels linked with hydraulic and landscape drivers

“…Therefore, future studies should include predictors associated with host fishes, mussel dispersal, and other land‐use patterns, such as mining and dams that may influence mussel populations in the Amazon. Management plans should include areas for conservation in both buffer and subcatchment scales since these are important for freshwater mussel distribution (Dobler et al., 2019 ).…”

“…Identification of suitable habitats for mussels is important for aquatic conservation because they may be found in a diverse array of habitats (Dobler et al., 2019 ; Smit & Kaeser, 2016 ). For example, mussels may occur in gravely or sandy river substrates (Allen & Vaughn, 2010 ; Steuer et al., 2008 ), whereas others may aggregate among large cobbles (Gangloff & Feminella, 2007 ) and similar flow refuges, which are sheltered and remain stable in periods of high flow (Morales et al., 2006 ).…”

No lake left behind: How well do U.S. protected areas meet lake conservation targets?

“…Furthermore, the southeastern U.S. contains the greatest diversity of fish, reptiles, and amphibians, but disproportionately few protected areas (Jenkins et al 2015). Studies outside the U.S. have found mixed associations between freshwater protection and representation of freshwater biodiversity (Abraham and Kelkar 2012, Chessman 2013, Guareschi et al 2015, Dobler et al 2019. Therefore, protected areas may not only insufficiently protect freshwaters, but also the full breadth of freshwater ecosystems and biodiversity.…”

Conservation status of two endangered freshwater mussel species in Bavaria, Germany: Habitat quality, threats, and implications for conservation management

“…Furthermore, the conservation of habitats of those species already protected may also gain from legislative measures. Dobler, Geist, Stoeckl, and Inoue () showed that designated sites such as the special areas of conservation (SACs) selected for mussel species in Bavaria are frequently too small to be effective, as in many cases the SACs do not cover the catchment areas of the streams. This means that critical factors such as nutrient and sediment loads originating from the wider catchment cannot be reduced using the legal instruments of the Habitats Directive.…”