CONICET | Buscador de Institutos y Recursos Humanos

Land transformation in the Pampas grasslands have led to habitat loss for birds. Roadside borders provide remnant habitats, although species may use them differently. Here, we determine which characteristics of roadsides and the surrounding habitat matrix influence their use by birds and their behaviours. During the breeding season of 2016, we sampled birds, vegetation and food resources in 87 roadside borders. We also estimated the amount of grassland, wetland, woodland, and modified land in the habitat matrix surrounding those borders. For the most common species, we recorded their behaviour and analysed the associations between their abundance and border characteristics, matrix characteristics and food. We detected 3819 individuals of 89 species using borders for feeding, roosting and nesting. According to behavioural observations, wetland birds were the most selective in environment use, whereas grassland and woodland birds used a range of environments such as grassland, woodland and wetland. Among 23 analysed species (i.e. the most frequent), eight responded only to border variables, four responded to matrix variables, and five responded to both. The most relevant variables on species richness and species abundance were woodland and wetland cover of borders. Species were generally associated with their nesting sites. Species responded differently to the surrounding matrix according to their habitat requirements and probably also to their sensitivity to habitat modification. Since birds respond to the size of habitat patches in the matrix, the degree of conservation in the Pampas do influence bird communities. Characteristics of borders and surroundings should be considered in management strategies.