Habitat heterogeneity promotes bird diversity in agricultural landscapes: Insights from remote sensing data

Understanding the main drivers of biodiversity loss in Europe's agricultural landscapes has been a research priority in the last decades. One of the most important factors promoting biodiversity in farmed landscapes is habitat heterogeneity, which has often proved crucial for avian species and communities. Birds are highly sensitive to environmental changes and make use of a broad range of ecological niches, thus being exceptionally sensitive to the loss of habitat heterogeneity. Remote sensing data are particularly suited to quantify habitat heterogeneity at fine scales over relatively large extents, allowing to consider how dif-ferent measures of heterogeneity may affect biotic communities at a regional scale. Here, we used airborne LiDAR (Light Detection And Ranging) and satellite multispectral data to derive vegetation canopy height and primary productivity for 118 sites in complex agricultural landscapes in a region in the Central Alps. We computed different bird diversity indices and classi-fied bird species into guilds according to specific traits to analyse the relationship between avian communities and different fac-ets of habitat heterogeneity. Results confirmed that habitat heterogeneity is essential in shaping rich and diverse bird communities, and it is particularly important for several farmland birds. By comparing the effects of canopy height, primary productivity, and specific vegetation features (e.g., cover of grassland, shrub, and tree layers), we showed how different habitat characteristics as well as landscape heterogeneity affected bird richness, diversity, functional entropy, and trait patterns. Land-scape and height heterogeneity, estimated by NDVI and LiDAR Rao's Q indices, strongly influenced all response variables, for example, high NDVI values promoted species diversity and ground-understory nesters, and shrub layer was important for ground-understory nesters and forest specialists. Finally, we provide recommendations for conservation practices and mitiga-tion measures to improve bird diversity in agricultural landscapes.

Automated summary

Understanding the main drivers of biodiversity loss in Europe's agricultural landscapes has been a research priority in the last decades. Habitat heterogeneity is crucial for promoting biodiversity in farmed landscapes, especially for avian species and communities. Remote sensing data, such as LiDAR and satellite multispectral data, can quantify habitat heterogeneity and analyze its effect on bird communities and different facets of biodiversity.