Identifying the relative fit of drivers of aquatic macrophyte species richness is necessary for the effective conservation of biodiversity in lakes and provides fundamental understanding of aquatic macrophyte communities. Using multiple regression, we investigate the relative influence of water quality, lake morphology, geographic and landscape drivers, and humans on the richness of macrophytes in lakes in the Adirondack Park of New York State. To further investigate species-area relationships in the dataset, we used null model analysis to test for the passive sampling hypothesis which is has a non-biological explanation for the phenomenon.
Results/Conclusions
We find, ordered by slope coefficient, bed area (.45), UTM X (.30), road density within 100m of a lake (.24), surface water area upslope (.18), elevation (-.17), and lake isolation (.14, larger values of represent less isolation) to explain 64% of the variation in species richness. We reject the passive sampling hypothesis for the species-area relationship regarding bed area, revealing a biologically relevant species-area relationship. We found no significant influence of lake area, watershed road densities, urban isolation, Y, lake and bed effective fetch, bed isolation, and water quality on richness. If the goal of conservation is promoting biodiversity, lake area, the categorization of “pristine waters”, and climate refugia should not be used as parameters in the conservation process. Our results also reveal insight into meta-community dynamics in aquatic macrophyte communities. At the regional scale, isolation is a significant driver of richness giving evidence to the relative importance of patch dynamics; while at the bed scale, isolation is insignificant, giving evidence to the importance of mass effects at the lake scale.