Ecological and acoustic responses of bush crickets to anthropogenic and natural ecotones

Ecotones occur naturally throughout complex landscapes. Each ecotone has particular ecological conditions resulting in species-specific responses. Across anthropogenic landscape mosaics both natural and cultural processes maintain ecotones. However, there is also a behavioural component associated with ecotones, allowing fine interpretation of ecotones in terms of animal responses, where traditional sampling has disadvantages. Singing bush crickets are often major components of soundscapes, with individuals having strong associations with certain vegetation types. Here we use ecoacoustic methods to determine how singing bush cricket species characterize the soundscape of natural vs. anthropogenic ecotones in a complex landscape. We compare the response of bush crickets to anthropogenic and natural ecotones based on acoustic species composition, acoustic activity, and total call times in response to measured vegetation characteristics. Eleven bush cricket species were identified from almost 90,000 calls from both natural and anthropogenic biotope interiors and their ecotones. Both the natural and anthropogenic ecotones were almost identical in assemblage composition, were diverse, and further supported high degrees of bush cricket singing activity. The bush cricket assemblages at these ecotones did not differ, yet they proved to be the turnover point between assemblages in the open vs. woodier sites. This complex landscape supported considerable environmental heterogeneity, reflected in the soundscape. Interestingly, we show here that both natural and anthropogenic ecotones have value for bush crickets in this semi-transformed landscape.