Consequences of swamp forest fragmentation on assemblages of vascular epiphytes and climbing plants: Evaluation of the metacommunity structure

Abstract

AimHabitat reduction in fragmented landscapes provides an opportunity to study the biogeographic patterns that drive changes in diversity in poorly studied metacommunities. In this study, colonization–extinction dynamics were indirectly evaluated through the analysis of the species–area relationship and the nestedness of vascular epiphytes and climbing plants in 30 swamp forest fragments.LocationCoast of the Araucanía Region in Chile.TaxonVascular epiphytes (16 species, mainly Pteridophytes) and climbing plants (15 species).MethodsWe used the database in Pincheira‐Ulbrich et al. (New Zealand Journal of Botany, 54, 2016, 458), where 904 trees were sampled and a total abundance of 41,097 fern fronds and 3,098 climbing stems were reported. For the species–area relationship, a simple linear regression model (SLR) and two models that consider the spatial autocorrelation of species richness among fragments, generalized least squares (GLS) and simultaneous autoregressive model (SAR), were compared. For the species nestedness, the nestedness measure based on overlap and decreasing fills (NODF) and weighted nestedness metric based on overlap and decreasing fill (WNODF) indexes were used on presence–absence and abundance matrices, respectively. These matrices were sorted by area size and distance from the largest fragment and then contrasted with the probability distribution of a randomized null model based on 10,000 simulations.ResultsThe results showed that the area size had a significantly positive effect on epiphyte species richness, while spatial autocorrelation played a fundamental role in explaining the richness of climbing plants. Both metacommunities had a general nestedness structure in terms of species incidence, which was determined first by area size and secondly by isolation.Main conclusionsOur results indicate that local colonization processes determined by species’ dispersal capacities could be the predominant mechanism for the spatial configuration of climbing plant species composition. On the other hand, selective extinction determined by patch size could characterize the spatial structure of epiphyte species’ composition.

Value of human‐modified forests for the conservation of canopy epiphytes

“…Human modification of forests negatively affects vascular epiphytes assemblages. The decrease of forest area drives a reduction of species richness through multiple pathways (Pincheira‐Ulbrich et al, 2018). For example, open habitats such as pasturelands are a potential dispersal barrier for animal‐dispersed taxa (Acevedo et al, 2020; Mondragón, Valverde, & Hernández‐Apolinar, 2015; Reid et al, 2016; Werner & Gradstein, 2008).…”

A 30-year update of the climbers and vascular epiphytes inventory of the Cerro Ñielol Natural Monument (La Araucanía, Chile): a database

“…These latter species would have an essential role as indicators of climate change ( Klausmeyer and Shaw 2009 , Martay et al 2016 ). One of the groups of plants sensitive to these changes are climbers and vascular epiphytes, which depend on forest trees for survival and show differentiated responses to environmental gradients so that they can become indicator species for environmental and biological changes in the ecosystem ( van der Heijden and Phillips 2008 , Pincheira-Ulbrich et al 2018 ). Indicator plants seem to be a reasonable starting point for a long-term monitoring programme since changes in the diversity of these species are amongst the best available predictors of the diversity for other taxa ( Pereira and Cooper 2006 ).…”