Island‐biogeographic patterns of spider communities on epiphytes depend on differential space use among functional groups

Abstract

Aim: Positive relationships between island size and species richness have been found for oceanic and non-oceanic islands. However, the effect of isolation, also predicted by island-biogeographical theory, seems challenging to test. Species-specific mechanisms drive the perception of distance and space for animals, and therefore isolation patterns are masked when described at the community level. We used epiphytic plants (canopy islands) and their spider communities to study how functional group and species-specific use of space modifies the effect of island-level predictors on species richness.Location: A coffee plantation near Xalapa, Mexico.Taxon: Spiders (Araneae), vascular epiphytes (Bromeliaceae, Piperaceae, Orchidaceae, Araceae, Pteridophyta). Methods:We collected canopy islands from three trees and recorded their three-dimensional position. Afterwards, we collected all epiphyte-dwelling spiders. We used Generalized Linear Models (GLMs) to analyse the effect of island size and isolation on the species richness of spider communities and community subgroups (guilds, mobility groups and families). Isolation was calculated using two metrics (aerial and walking distances) associated with different ways of mobility in the canopy (bridging and wandering respectively). We evaluated species-level associations with island features and tested for sample-size effects on GLMs using null-model analysis of ecological networks.Results: Although unimportant at the community level, isolation was more important than island size for some spider subgroups, while having negligible effects for others. Speciesspecific responses to isolation and island size were responsible for the variability in species richness patterns observed for broader subgroups (families, guilds and mobility groups).Specific responses of mobility groups to isolation metrics were in line with two ways of moving between islands; one using tree branches as pathways (walking isolation) and the other using silk threads to connect points directly across the air (aerial isolation). Main conclusions:Spatial patterns of epiphyte-dwelling spiders were explained better when functional traits were considered, and the effect of isolation became This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. is interested in functional biogeography of spiders living in plant microhabitats. He is interested in behavioural and physiological traits driving the perception of distance and isolation. Glenda Mendieta-Leiva studies ecological and biogeographical aspects of epiphyte biology. Dinesh Rao works with behavioural ecology of spiders and is interested in the ecological drivers of their spatial distribution. Maaike Y. Bader studies ecological and ecophysiological mechanisms determining the spatial distribution of plants, in particular epiphytes, bryophytes and trees near alpine tree...

Changes in diversity and community assembly of jumping spiders (Araneae: Salticidae) after rainforest conversion to rubber and oil palm plantations

“…Despite the prevalence of spiders in tropical canopies, we are unaware of any studies that have quantified the mechanisms influencing canopy-spider community assembly after rainforest conversion into cash-crop monoculture plantations. However, it has been demonstrated that tree canopy openness and vegetation complexity, for example, coverage by herbs, shrubs and epiphytes, affect local spider communities (Méndez-Castro et al, 2020;Méndez-Castro et al, 2018;Stenchly et al, 2011;Zheng, Li & Yang, 2015).…”

Habitat filtering and inferred dispersal ability condition across‐scale species turnover and rarity in Macaronesian island spider assemblages

“…Spiders are one of the most ubiquitous and diverse taxa in terrestrial ecosystems (Coddington & Levi, 1991). These arthropods are useful for understanding how dispersal and habitat interact (Florencio et al, 2016;Gavish & Ziv, 2016;Malumbres-Olarte et al, 2014), and in the field of insular biogeography, they are providing evidence of how isolation, mobility and microhabitat size affect the functionality of species and assemblages (Méndez-Castro et al, 2020) as well as colonisation and vicariance processes across archipelagos (Čandek et al, 2019;Gillespie, 2002;Rominger et al, 2015).…”

“…Spiders are one of the most ubiquitous and diverse taxa in terrestrial ecosystems (Coddington & Levi, 1991). These arthropods are useful for understanding how dispersal and habitat interact (Florencio et al, 2016; Gavish & Ziv, 2016; Malumbres‐Olarte et al, 2014), and in the field of insular biogeography, they are providing evidence of how isolation, mobility and microhabitat size affect the functionality of species and assemblages (Méndez‐Castro et al, 2020) as well as colonisation and vicariance processes across archipelagos (Čandek et al, 2019; Gillespie, 2002; Rominger et al, 2015). Furthermore, spiders can be used to understand the effects of dispersal, between‐habitat differences and disturbance on the SADs of assemblages, providing useful information for conservation management (Boieiro et al, 2018; Borges et al, 2008; Cattin et al, 2003; Kaltsas et al, 2019; Kondratyeva et al, 2019; Leroy et al, 2014; Morel et al, 2019).…”

Spatial relationships between spiders and their host vascular epiphytes within shade trees in a Mexican coffee plantation

“…The variables used for tree selection were tree height (T‐I = 14.8 m, T‐II = 14.8 m, T‐III = 12.6 m), stem diameter at breast height (T‐I = 0.52 m, T‐II = 0.51 m, T‐III = 0.59 m), and canopy cover—estimated from the largest crown radius—(T‐I = 4.3 m, T‐II = 6.2 m, T‐III = 7.8 m). Further details are reported in Méndez‐Castro et al (2018, 2020).…”

“…Since epiphytes are the main habitat used by different canopy‐dwelling animals (Cruz‐Angón et al, 2009; Cruz‐Angón & Greenberg, 2012), their heterogeneous spatial distribution within trees can be expected to promote a heterogeneous distribution of their associated‐fauna. After the colonization of epiphytes, various mechanisms such as environmental filters, competition, predation, or dispersal limitation (Méndez‐Castro et al, 2018, 2020) can determine the spatial distribution of animals within the epiphyte habitat of each tree. If these mechanisms do not have a significant role, the spatial distribution of the associated fauna is expected to simply follow that of the epiphytic habitat.…”