Nuestro Rio Salto Del Tequendama

Biodivers Conserv (2011) 20:987–999 DOI 10.1007/s10531-011-0008-1 ORIGINAL PAPER

Habitat edge context and the distribution of phyllostomid bats in the Andean forest and anthropogenic matrix in the Central Andes of Colombia
´ ´ Natalia Cortes-Delgado • Jairo Perez-Torres

Received: 22 April 2010 / Accepted: 31 January 2011 / Published online: 20 February 2011 Ó Springer Science+BusinessMedia B.V. 2011

Abstract Bats play an important role in the ecosystem as seed dispersers, pollinators and pest controllers. In particular, frugivorous bats are important for regeneration processes in open and degraded areas, because they disperse the seeds of pioneer plant species, which are essential for succession. Depending on the type of habitat that is established at the fragment edge,resources and bat movement patterns toward open areas can be affected. The structure and composition of bats was compared between two ‘interior-edge-pasture’ ˜ gradients, in an Andean forest fragment located at the Reserva Natural la Montana del ´ Ocaso (Quindıo, Colombia). The two edge-types considered were forest-edge and bambooedge (Guadua angustifolia, Poaceae), both located in the same fragment. Batabundance was significantly different in the two edge habitats. The forest-edge is a soft edge, in that it allows bat species to move from the interior of the forest to the pasture in front of it. In contrast, the bamboo-edge can be defined as semi-permeable, because it allows less movement of species and individuals from the interior to the pasture. Here we evaluate the possible effects of habitatedge type on bat movement in degraded areas in the main coffee producing region of Colombia. Keywords Bamboo-edge Á Chiroptera Á Forest-edge Á Forest fragmentation Á Phyllostomidae

Introduction In terms of species diversity, tropical forests are among the richest ecosystems on the planet (Harrison 2005). In particular, Colombia contains one of the most diverse
´ N. Cortes-Delgado (&) ´ ´Ecologıa Funcional, Instituto de Ecologıa, A.C., Carretera Antigua a Coatepec N° 351, El Haya, Xalapa, Veracruz, Mexico e-mail: natalia.cortes@posgrado.inecol.edu.mx; taliks84@gmail.com ´ J. Perez-Torres ´ ´ ´ Laboratorio de Ecologıa Funcional, Unidad de Ecologıa y Sistematica (UNESIS), Pontificia ´ Universidad Javeriana, Carrera 7 No. 43-82, Edificio 53, Of. 406B, Bogota, Colombia

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populations of terrestrial vertebrates in the world, of which a significant percentage are found in the Andean forests. The Colombian Andes, and in particular the mountainous region between the central and western mountain-ridges (known as the ‘‘eje-cafetero’’), is one of the largest coffee-producing regions in the world. At the same time, it is a region with oneof the highest deforestation rates and habitat loss, where only 22% of ´ the original Andean forest remains (Rodrıguez and Arango 2004). Although coffee is still the main crop, coffee plantations are being increasingly replaced with cattle pasture. One of the consequences of forest fragmentation is the formation of habitat edges, which are defined as contact-zones between structurally differentplant communities (Williams-Linera 1991), or as the interface between two adjacent ecosystems (Murcia 1995). Two processes take place at habitat edges: (1) an exchange of energy and/or organisms and (2) changes in biophysical processes, ecosystem composition and structure (Harper et al. 2005). Edge permeability, defined as the extent to which a border increases ´ or decreases energy and matter-flux(Lopez-Barrera et al. 2007), is an important factor for species movement across the landscape. Accordingly, edges can act as physical barriers that are never crossed by some organisms, e.g. because they are habitat-specialists or they face a higher predation risk in adjacent habitats. Such edges are designated as ‘‘hard or impermeable-edges’’. In contrast, edges that allow organism movement are...