Loss of temporal structure of tropical soundscapes with intensifying land use in Borneo.

Conservation and sustainable management efforts in tropical forests often lack reliable, effective, and easily-communicated ways to measure the biodiversity status of a protected or managed landscape. The sounds that many tropical species make can be recorded by pre-programmed devices and analysed to yield measures of biodiversity. Interpreting the resulting soundscapes has developed along two paths: analysing the whole soundscape using acoustic indices, used as a proxy of biodiversity, or focusing on individual species that can be either manually or automatically recognized from the soundscape. Here we develop an intermediate approach to divide the soundscape into frequency categories belonging to broad taxonomic groups of vocalizing animals. While the method was unable to distinguish between amphibian and mammal communities, it was successful in assigning parts of the soundscape as likely produced by birds and insects. Applying the approach in Borneo revealed that, with increasing land use intensity, i) the spectral saturation of the soundscape, a proxy of species richness, loses dawn and dusk peaks, ii) bird acoustic communities lose recurrent diurnal patterns, becoming less synchronized across sites, and that iii) insect Soundscape Saturation increases at night. If soundscapes are partitioned similarly in different regions, our method could be used to bridge soundscape-level and individual-species level analyses. Regaining dawn and dusk peaks, the synchrony of bird acoustic communities, and losing nocturnal dominance of insect could be used as a set of simple indicators of tropical forest retaining high levels of biodiversity.

Using food-web theory to conserve ecosystems.

Food-web theory can be a powerful guide to the management of complex ecosystems. However, we show that indices of species importance common in food-web and network theory can be a poor guide to ecosystem management, resulting in significantly more extinctions than necessary. We use Bayesian Networks and Constrained Combinatorial Optimization to find optimal management strategies for a wide range of real and hypothetical food webs. This Artificial Intelligence approach provides the ability to test the performance of any index for prioritizing species management in a network. While no single network theory index provides an appropriate guide to management for all food webs, a modified version of the Google PageRank algorithm reliably minimizes the chance and severity of negative outcomes. Our analysis shows that by prioritizing ecosystem management based on the network-wide impact of species protection rather than species loss, we can substantially improve conservation outcomes.

Prioritising in situ conservation of crop resources: a case study of African cowpea (Vigna unguiculata).

Conserving crop wild relatives (CWR) is critical for maintaining food security. However, CWR-focused conservation plans are lacking, and are often based on the entire genus, even though only a few taxa are useful for crop improvement. We used taxonomic and geographic prioritisation to identify the best locations for in situ conservation of the most important (priority) CWR, using African cowpea (Vigna unguiculata (L.) Walp.) as a case study. Cowpea is an important crop for subsistence farmers in sub-Saharan Africa, yet its CWR are under-collected, under-conserved and under-utilised in breeding. We identified the most efficient sites to focus in situ cowpea CWR conservation and assessed whether priority CWR would be adequately represented in a genus-based conservation plan. We also investigated whether priority cowpea CWR are likely to be found in existing conservation areas and in areas important for mammal conservation. The genus-based method captured most priority CWR, and the distributions of many priority CWR overlapped with established conservation reserves and targets. These results suggest that priority cowpea CWR can be conserved by building on conservation initiatives established for other species.