Emergent spatial pattern of herpetofauna in Alabama, USA

Analyzing spatial pattern of regional biodiversity and its relationships with environmental factors is important for biodiversity conservation at large scales. The emergent spatial pattern of herpetofauna in Alabama is examined by combining thousands of historical records from 132 species of 24 families and environmental conditions. Our results indicate that species richness of herpetofauna increases with the increase of latitude, while it decreases with the increase of elevation. A negative spatial association exists between amphibians and reptiles on the scale of 10 km2, but 40% of habitats are still shared by amphibians and reptiles at this scale. The highest species richness of herpetofauna is in the Mobile and Baldwin Counties. Power-law relation exists between the county size and the average species richness. Total stream length, and road density are highly correlated with species richness at the county level. With the increase of annual precipitation, species richness decreases. Species richness is higher in the area with the annual average temperature around 17-18 °C. Herpetofaunal diversity in the Coosa/Tallapoosa River, the Alabama River, and the Tombigbee River basins is relatively higher than in the Perdido River and the Escatawpa River basins. The highest species richness exists at the Gulf Coastal Plain, but its species density is the lowest. The highest species richness of herpetofauna exists in the Longleaf-Slash Pine and Loblolly-Shortleaf Pine forests, while lower in Oak- Hickory forest. The emergent spatial pattern may provide important implications for herpetofauna conservation in the face of global climate change and large-scale habitat destruction. The spatial pattern and the possible underlying ecological processes have to be considered for the large scale land zoning and planning.