The Fynbos and sUcculent Karoo biomes do not have exceptional local ant richness.

Brigitte Braschler,Kevin J Gaston,Steven L Chown

doi:10.1371/journal.pone.0031463

Brigitte Braschler, Kevin J Gaston + Show 1 more

Open Access

https://doi.org/10.1371/journal.pone.0031463

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Journal: PloS one	Publication Date: Mar 2, 2012
Citations: 69	License type: CC BY 4.0

Affiliation: University of Sheffield, Stellenbosch University

Abstract

BackgroundThe Fynbos (FB) and Succulent Karoo biomes (SKB) have high regional plant diversity despite relatively low productivity. Local diversity in the region varies but is moderate. For insects, previous work suggests that strict phytophages, but not other taxa, may have high regional richness. However, what has yet to be investigated is whether the local insect species richness of FB and SKB is unusual for a region of this productivity level at this latitude, and whether regional richness is also high. Here we determine whether this is the case for ants.Methodology/Principal FindingsWe use species richness data from pitfall traps in the FB and SKB in the Western Cape Province, South Africa and a global dataset of local ant richness extracted from the literature. We then relate the globally derived values of local richness to two energy-related predictors—productive energy (NDVI) and temperature, and to precipitation, and compare the data from the FB and SKB with these relationships. We further compare our local richness estimates with that of similar habitats worldwide, and regional ant richness with estimates derived from other regions. The local ant species richness of the FB and SKB falls within the general global pattern relating ant richness to energy, and is similar to that in comparable habitats elsewhere. At a regional scale, the richness of ants across all of our sites is not exceptional by comparison with other regional estimates from across the globe.Conclusions/SignificanceLocal richness of ants in the FB and SKB is not exceptional by global standards. Initial analyses suggest that regional diversity is also not exceptional for the group. It seems unlikely that the mechanisms which have contributed to the development of extraordinarily high regional plant diversity in these biomes have had a strong influence on the ants.

Highlights

Terrestrial biodiversity is not evenly distributed across the surface of the Earth
In particular we examine whether the data from the FB and Succulent Karoo biomes (SKB) falls within the general global relationships between ant species richness and two energy-related predictors – normalised difference vegetation index (NDVI, used as a proxy for productive energy) and temperature
By contrast with the South African analyses, ant species richness at the global scale was not significantly related to NDVI (Figure 2A), but showed significant curvilinear relationships with precipitation and temperature (Figures 2B and 2C)

Summary

Introduction

Terrestrial biodiversity is not evenly distributed across the surface of the Earth. It is typically highest in the tropics, a pattern repeated in many taxonomic groups and one which has a considerable history [1]. The Fynbos Biome (FB) and the Succulent Karoo Biome (SKB) [9], located at the southern tip of Africa, are clear examples of regional exceptions to the general latitudinal pattern in species richness and its relationship with available energy. These biodiversity hotspots have exceptionally high regional plant diversity and endemism despite lying well outside the tropics and having relatively low productivity [10],[11],[12]. The Fynbos (FB) and Succulent Karoo biomes (SKB) have high regional plant diversity despite relatively low productivity. We determine whether this is the case for ants

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