Area, isolation, disturbance and age effects on species richness of summer waterbirds in post-mining subsidence lakes, Anhui, China

Background The species–area relationship is one of the best documented patterns in community ecology. Factors influencing species–area relationship are still not well understood. Since the proposal of the equilibrium theory of island biogeography, many studies have tested the effects of area and isolation, estimating effects of disturbance and patch age were scarce and should also be important bearing.

Methods We investigated summer waterbird species richness in 38 post-mining subsidence lakes in Huainan and Fuyang, Anhui, China, May 25–June 12, 2016. We examined the effects of lake area, isolation (distance to natural water bodies), aquaculture disturbance, lake age and lake state (still sinking or not sinking) on summer waterbird species richness with multivariable linear regression method and model selection method.

Results Our results from multivariable linear regression and model selection were consistent, which showed that species richness was positively related with lake area and negatively related with isolation. Aquaculture disturbance negatively influenced species richness. Highest species richness were found in lakes under intermediate intensity of aquaculture activities with area less than 100 ha and lakes under low intensity of aquaculture activities with area greater than 100 ha. Lake age and lake state had no significant effects on species richness.

Conclusions Species richness was most related with lake area, aquaculture disturbance, and isolation, with lake area had a positive effect, while aquaculture activities and isolation had a negative effect. What's more, aquaculture activities significantly changed the slope of species–area relationship and might impede us finding a relationship between species richness and lake age.