Can current farmland landscapes feed declining steppe birds? Evaluating arthropod abundance for the endangered little bustard (Tetrax tetrax) in cereal farmland during the chick-rearing period: Variations between habitats and localities.

David González Del Portillo,Beatriz Arroyo,Guillermo García Simón,Manuel B Morales

doi:10.1002/ece3.7271

David González Del Portillo, Beatriz Arroyo + Show 2 more

Open Access

https://doi.org/10.1002/ece3.7271

Copy DOI

Abstract

Agriculture intensification threatens farmland bird populations because, among other reasons, it reduces the availability of food resources required to rear their offspring. In our study, we sampled and analyzed total arthropod abundance, biomass and richness, and orthopteran and coleopteran abundance and biomass in different agricultural habitats (alfalfa fields, stubble fields, grazed fields, and field margins) across 4 study localities with different levels of agriculture abandonment–intensification, comparing between areas used and not used by one of the most threatened farmland birds in Europe, the little bustard (Tetrax tetrax), during the chick‐rearing season. Field margins were the taxonomically richest habitat, while alfalfa fields presented significantly higher total arthropod abundance and biomass than other habitats. All arthropod variables were the highest in the localities with clear conservation‐focused agrarian management, and the lowest in the most intensive one. Areas used by little bustards had higher orthopteran and coleopteran abundance and biomass than nonused areas, except for coleopteran biomass in grazed fields. These results highlight the relevance of these arthropods for the species, the importance of dry alfalfa fields as food reservoirs in this critical time of year, the food scarcity in sites where agrarian management disregards farmland bird conservation, and the role of stubbles as providers of food resources during the chick‐rearing season in areas used by the species. The adequate management of alfalfa fields and stubbles to provide those key resources seems crucial to improve little bustard breeding success.

Highlights

Over the last 50 years, agricultural management has changed due to the intensification of farming techniques (Chamberlain et al, 2000; Fuller et al, 1995; Sanderson et al, 2005; Santos & Suárez, 2005; Siriwardena et al, 2000)
Our results show that field margins were the taxonomically richest habitat, alfalfa fields presented significantly higher total arthropod biomass and abundance than other dominant habitats in the study localities
Areas used by little bustards had higher orthopteran and coleopteran abundance and biomass than nonused areas, except for grazed fields where coleopteran abundance was higher in nonused than in used ones

Summary

Introduction

Over the last 50 years, agricultural management has changed due to the intensification of farming techniques (Chamberlain et al, 2000; Fuller et al, 1995; Sanderson et al, 2005; Santos & Suárez, 2005; Siriwardena et al, 2000). Intensive agricultural practices include early harvesting, the use of silage systems, the application of agrochemicals, and the reduction of nonproductive, semi-natural areas such as fallows, hedgerows, and field boundaries, and their ultimate end is to increase crop productivity (Grigg, 1989; O’Connor & Shrubb, 1986; Stoate, 1996; Whittingham et al, 2006) These practices, aided by the mechanization of agricultural works, are at the root of bird farmland population declines, as they are associated with the loss of food resources (Brickle et al, 2000; Campbell et al, 1997; Evans et al, 1997; Potts, 1986), the reduction of nesting areas (Chamberlain et al, 2000; Wilson et al, 1997), or increased mortality (Crick et al, 1994; Green, 1995)

Objectives

Findings

Discussion

Conclusion