Agricultural adapters from the vineyard landscape impact native oak woodland birds

Abstract

Agricultural expansion changes wildlife communities. Some species adapt to working lands, increasing their relative abundance in these modified landscapes, and this may result in spillover effects for communities in adjacent wildlands. These effects remain largely undocumented, even though they can affect biodiversity conservation. We conducted bird surveys at 130 Mediterranean-climate oak woodland locations that exist across a gradient of nearby vineyard development. We used zero inflated Poisson (ZIP) N-mixture models to analyze the relationships among detected bird species, local vegetation, and surrounding vineyard land cover. We used joint species distribution modeling (JSDM) to measure species co-occurrence patterns and account for the influence of the surrounding agricultural land in order to explore indirect effects between bird communities associated with vineyard expansion and oak woodland remnants. We identified 10 species as agricultural adapters based on their positive associated with vineyard land cover. Co-occurrence patterns suggested that i) agricultural adapter species may negatively interact with certain species associated with oak woodlands in adjacent wildlands, so competition with agricultural adapters may be an important driver of biotic homogenization of the community, and (ii) some positive species interactions were detected, especially among insectivore foliage gleaners, which may be facilitated by niche partitioning. Continued examination of spillover effects from agricultural land into adjacent natural areas is warranted in light of global species declines and biotic homogenization.