Abstract
Humanity is facing a biodiversity crisis, with freshwater-associated biodiversity being in particularly dire state. Novel ecosystems created through human use of mineral resources, such as gravel pit lakes, can provide substitute habitats for conservation of freshwater and riparian biodiversity. However, many of these artificial ecosystems are managed for recreational fisheries and may exhibit high recreational use intensity, which may limit the biodiversity potential of gravel pit lakes.
We assessed the species richness of several taxa present in gravel pit lakes and compared a range of taxonomic biodiversity metrics of lakes managed for recreational fisheries (N = 16) and unmanaged reference lakes (N = 10), while controlling for non-fishing related environmental variation.
The average species richness of all examined taxa (plants, amphibians, dragonflies, damselflies, waterfowl, songbirds) was similar among both lake types and no faunal or floral breaks were revealed when examining the pooled species inventory of managed and unmanaged lakes. Similarly, there were no differences among management types in the presence of rare species and in the Simpson diversity index across all the taxa that we assessed.
Variation in species richness among lakes was correlated with woody habitat, lake morphology (size and steepness) and land use, but not with the presence of recreational fisheries. Thus, non-fishing related environmental variables have stronger effects on local species presence than recreational-fisheries management or the presence of recreational anglers.
Collectively, we found no evidence that anglers and recreational-fisheries management constrain the development of aquatic and riparian biodiversity in gravel pits of the study region.
Footnotes
We excluded the species accumulation curves because they did not realy add to the story and the statistic wasn’t quite interpretable. We rearranged the environmental PCA for landuse a little bit and therefor got differing statisitcs in the model selection process. We excluded the multivariate analysis of conservation values and used only one red list to calculate it for the univariate comparisons. We added the simpson index to the analysis. We overall shortened the paper.