Influence of patch- and landscape-level factors on bird assemblages in a fragmented tropical landscape

Abstract:

A major challenge in studies of habitat fragmentation is to determine the influence of patch quality and landscape context on patch use by animals. Few studies have simultaneously examined effects of patch (area, shape, and vegetation structure) and landscape (e.g., amount of arboreal vegetation in close proximity) on abundance patterns of animals. In this study, we examined how these characteristics influence bird species distribution and abundance in a pasture-dominated landscape in the Los Tuxtlas region of Veracruz, Mexico. We focused on three types of landscape elements: forest edge sites (n = 8), forest remnants (n = 8), and riparian forest remnants (n = 9). We quantified habitat use and community composition of birds by conducting seven counts of birds in each site between October 1996 and April 1997. Species typically restricted to forest were influenced by two patch-level factors, whereas species not so restricted were influenced by both patch- and landscape-level factors. At a community level, bird assemblages were more similar among sites within a given habitat type than among types, when all three landscape elements were analyzed simultaneously. Stepwise redundancy analyses showed that the amount of continuous forest within 500 m of the site edge and the amount of arboreal vegetation cover within 100 m and between 100 and 500 m of the edge were most influential in separating bird assemblages found in forest edge sites from those found in remnants. In a second redundancy analysis based only on remnants, two patch-level variables (shape and area) and one landscape variable (amount of continuous forest within 500 m) largely separated forest remnants from riparian remnants. To manage birds in the fragmented Los Tuxtlas landscape, large forest blocks should be conserved because certain birds rely on this habitat. Remnants of various shapes and sizes should be conserved because they may provide habitat for species that are somewhat tolerant of forest disturbance as well as generalist species.

Año de publicación:

2001

Keywords:

• Indicator species assemblages
• Landscape level
• HABITAT FRAGMENTATION
• Forest remnant
• Forest edge
• Conservation
• Bird community composition
• Southern Mexico
• Patch level
• Riparian remnant
• Forest-restricted species

Fuente:

scopus