Nested species assemblages as a tool to detect sensitivity to forest fragmentation: the case of cloud forest birds

Abstract

In an ecological community, groups of species may or may not have a nested structure. Furthermore, any nested structure detected could have several causes, each of which would have to be identified, since they may have important theoretical and management implications. In this paper, I assessed the nested structure of bird communities using cloud forest fragments in eastern Mexico to identify bird species and groups of species sensitive to cloud forest fragmentation. Sensitive species were expected to have a nested arrangement highly correlated with forest fragmentation intensity. Analysis identified the following groups of birds as showing a nested structure highly correlated with cloud forest fragmentation: birds with a body mass between 100 and 300 g and larger than 600 g, some trophic behavioural guilds (terrestrial granivore, terrestrial granivore–frugivore, understory granivore–frugivore, arboreal granivore–frugivore, gleaning terrestrial insectivore, gleaning understory insectivore, cliff gleaning insectivore, nocturnal aerial insectivore, diurnal raptor, nocturnal raptor, terrestrial omnivore, scavenger), forest interior and generalist birds, species restricted to cloud forest, and threatened species. This study shows that the analysis of the nested species assemblage can be considered a useful tool to identify species sensitivity to ecological or landscape patterns and processes, in this case, species or groups of species affected by a fragmented landscape pattern.

Shifts in resident bird communities associated with cloud forest patch size in Central Veracruz, Mexico

“…Martínez- Morales (2005bMorales ( , 2007 found a greater number of species in larger fragments, contrasting with our observed higher species richness in medium-sized fragments. This could be caused by the persistence of larger expanses of cloud forest, reaching 16,298 ha, in northeast Hidalgo (Martínez-Morales 2007), which provide avian communities with resistance to local extinctions (Brooks et al 1999) and increase the likelihood of occurrence of forest-dependent species.…”

“…Consequently, the presence of forestinterior species seems to be affected by characteristics generally associated with fragment size, such as fragment connectivity, increased border effect with fragment size reduction, time of fragment isolation, and the matrix in which the fragments are embedded (Hoover et al 1995, Renjifo 1999, Ibarra-Macias et al 2011. These factors may have a greater impact on forest-interior species, understory insectivores, and large-bodied frugivores because these species exhibit lower abundances in smaller fragments (Martínez-Morales 2005a,2005b, 2007; however, future studies are needed to validate the existence and extent of such patterns.…”

“…Avian communities within these forests have a high degree of habitat specialization and low dispersal capabilities, which could make them particularly susceptible to habitat fragmentation (Stratford and Robinson 2005, Boscolo et al 2008, Moore et al 2008. Studies of cloud forest bird communities in Hidalgo, Mexico, found that forestinterior species, such as understory insectivores and large-bodied frugivores, had lower abundances in smaller fragments (Martínez-Morales 2005a, 2005b, 2007. Another study of small fragments of tropical premontane cloud forest in Costa Rica found variability in species richness and species turnover rates among years for fragments smaller than 10 ha, whereas larger fragments had more stable community dynamics (Borgella and Gavin 2005).…”

Nestedness in forest mammals is dependent on area but not on matrix type and sample size: an analysis on different fragmented landscapes

“…Extinction-generated nested patterns in fragmented landscapes are of particular interest for conservation, as they imply a predictable order for the loss of species (Ganzhorn and Eisenbeiss, 2001;Martinez-Morales, 2005). Such an order, coupled with inferences on the numbers of species taken from species-area relationships, can be used to predict which species will be lost following an eventual reduction in the area of available habitats (Macdonald and Brown, 1992).…”

“…Cutler, 1991;Fischer and Lindenmayer, 2005;Martinez-Morales, 2005;Nupp and Swihart, 2000;Wang et al, 2010). This might produce results that lack generality, which may explain the absence of a general pattern (Wright et al, 1998).…”