Arthropod distribution in a tropical rainforest: tackling a four dimensional puzzle
Basset, Yves; Cizek, Lukas; Cuénoud, Philippe; Didham, Raphael K.; Novotny, Vojtech; Ødegaard, Frode; Roslin, Tomas; Tishechkin, Alexey K.; Schmidl, Jürgen; Winchester, Neville N.; Roubik, David W.; Aberlenc, Henri-Pierre; Bail, Johannes; Barrios, Héctor; Bridle, Jonathan R.; Castano-Meneses, Gabriela; Corbara, Bruno; Curletti, Gianfranco; da Rocha, Wesley Duarte; de Bakker, Domir; Medianero, Enrique; de Oliveira, Evandro Gama; Orivel, Jérôme; Marc, Pollet; Rapp, Mathieu; Ribeiro, Sérvio P.; Roisin, Yves; Schmidt, Jesper B.; Sørensen, Line; Lewinsohn, Thomas M.; Leponce, Maurice; Kitching, Roger L.
Abstract
Quantifying the spatio-temporal distribution of arthropods in tropical rainforests represents
a first step towards scrutinizing the global distribution of biodiversity on Earth. To date moststudies have focused on narrow taxonomic groups or lack a design that allows partitioning
of the components of diversity. Here, we consider an exceptionally large dataset (113,952
individuals representing 5,858 species), obtained from the San Lorenzo forest in Panama,
where the phylogenetic breadth of arthropod taxa was surveyed using 14 protocols targeting
the soil, litter, understory, lower and upper canopy habitats, replicated across seasons
in 2003 and 2004. This dataset is used to explore the relative influence of horizontal, vertical
and seasonal drivers of arthropod distribution in this forest. We considered arthropod abundance,
observed and estimated species richness, additive decomposition of species richness,
multiplicative partitioning of species diversity, variation in species composition,
species turnover and guild structure as components of diversity. At the scale of our study
(2km of distance, 40m in height and 400 days), the effects related to the vertical and seasonal
dimensions were most important. Most adult arthropods were collected from the soil/
litter or the upper canopy and species richness was highest in the canopy. We compared
the distribution of arthropods and trees within our study system. Effects related to the seasonal
dimension were stronger for arthropods than for trees. We conclude that: (1) models
of beta diversity developed for tropical trees are unlikely to be applicable to tropical arthropods;
(2) it is imperative that estimates of global biodiversity derived from mass collecting of
arthropods in tropical rainforests embrace the strong vertical and seasonal partitioning
observed here; and (3) given the high species turnover observed between seasons, global
climate change may have severe consequences for rainforest arthropods.