Habitat diversity promotes bat activity in a vineyard landscape

Abstract

Intensification of agricultural production has greatly limited the capacity of agricultural land to support other species. Maintaining landscape heterogeneity in and around agricultural landscapes can help conserve biodiversity and potentially natural pest control. Whereas bats (order: Chiroptera) are highly valued as natural predators of agricultural pests, little is known about the distribution and abundance of bat species across different types of agricultural landscapes. The objective of our study was to assess how local remnant habitat and surrounding natural areas influence bat activity levels within a vineyard landscape. To accomplish this, we conducted acoustic surveys at 21 vineyards within the North Coast wine-grape growing region of California. Using generalized linear mixed-models, we assessed the influence of local remnant habitat and surrounding natural areas to predict overall and species-specific activity patterns. A total of 14,613 bat passes were recorded, of which 80% were identified by a random forest classifier as either Tadarida brasiliensis the Brazilian free-tailed bat (25%), Myotis yumanensis the Yuma Myotis (24%), or Eptesicus fuscus the big brown bat (23%). The results of our models indicate that total bat activity, and the activity of each of the common bat species, was higher adjacent to remnant vegetation along the edges of vineyards as compared to within the vineyard, but that the effect of landscape-scale characteristics on bat activity was weak. This suggests that natural trees and shrubs should be conserved and restored throughout the vineyard landscape to enhance bat abundance for a win-win agricultural production and conservation solution.