A Tank Bromeliad Favors Spider Presence in a Neotropical Inundated Forest.

Yann Hénaut,Laurent Pélozuelo,Alain Dejean,Régis Céréghino,Bruno Herault,Frédéric Azémar,Bruno Corbara,Ulrike G Munderloh

doi:10.1371/journal.pone.0114592

Abstract

Tank bromeliads are good models for understanding how climate change may affect biotic associations. We studied the relationships between spiders, the epiphytic tank bromeliad, Aechmea bracteata, and its associated ants in an inundated forest in Quintana Roo, Mexico, during a drought period while, exceptionally, this forest was dry and then during the flooding that followed. We compared spider abundance and diversity between ‘Aechmea-areas’ and ‘control-areas’ of the same surface area. We recorded six spider families: the Dipluridae, Ctenidae, Salticidae, Araneidae, Tetragnathidae and Linyphiidae among which the funnel-web tarantula, Ischnothele caudata, the only Dipluridae noted, was the most abundant. During the drought period, the spiders were more numerous in the Aechmea-areas than in the control-areas, but they were not obligatorily associated with the Aechmea. During the subsequent flooding, the spiders were concentrated in the A. bracteata patches, particularly those sheltering an ant colony. Also, a kind of specificity existed between certain spider taxa and ant species, but varied between the drought period and subsequent flooding. We conclude that climatic events modulate the relationship between A. bracteata patches and their associated fauna. Tank bromeliads, previously considered only for their ecological importance in supplying food and water during drought, may also be considered refuges for spiders during flooding. More generally, tank bromeliads have an important role in preserving non-specialized fauna in inundated forests.

Highlights

Confronted with global warming, species may survive if their climate envelopes are wide enough to buffer new environmental conditions or if they are capable of moving to more suitable areas
Impact of Aechmea bracteata presence and flooding on spider distribution Aechmea presence has a significant positive effect on the number of spiders, the contrary being true for flooding (Table 1A), and Aechmea-areas harbored significantly more spiders than expected by chance during flooding.This situation was mostly due to a decrease in Ischnothele caudata (Dipluridae), the only funnel-web tarantula noted, which represented 70% of the spiders recorded during the dry period and 42% during flooding
A. bracteata permits spiders to survive a prolonged drought, something noted for other spider taxa [13,14,15]

Summary

Introduction

Confronted with global warming, species may survive if their climate envelopes are wide enough to buffer new environmental conditions or if they are capable of moving to more suitable areas. Since 1976, there has been an increase in the frequency and intensity of El Nino and La Nina episodes related to global warming [4]. These episodes correspond to sea-surface temperature anomalies across the tropical Pacific Ocean which impact the atmospheric circulation worldwide, causing environmental changes with opposing effects [5]. In the Yucatan Peninsula, this phenomenon will be amplified in the future because this area is one of the most responsive tropical regions to changes in global climate; there, decreases in precipitation during La Nina episodes result in severe droughts [6]

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Results

Conclusion