Similar compositional turnover but distinct insular environmental and geographical drivers of native and exotic ants in two oceans

Guillaume Latombe, Núria Roura Pascual, Cang Hui

Research output: Contribution to journalArticlepeer-review

Abstract

Aim
This study aims to quantify the patterns in compositional turnover of native and exotic ants on small islands in two oceans, and to explore whether such patterns are driven by similar environmental, geographical and potentially biotic variables.

Location
Pacific and Atlantic islands.

Time period
Present.

Major taxa studied
Ants.

Methods
We applied Multi-Site Generalised Dissimilarity Modelling (MS-GDM), which relates zeta diversity, the number of species shared by a given number of islands, to differences in environmental, geographical and biotic drivers. The use of zeta diversity enabled us to differentiate the contribution of rare species (shared by few islands) from those of widespread ones (shared by multiple islands) to compositional turnover. For completion, we also related species richness of insular ants per island with the same set of explanatory variables using Generalised Additive Models (GAM).

Results
Pacific and Atlantic islands have similar patterns of ant species turnover and richness, albeit partly driven by different drivers. Native and exotic species turnover are mostly explained by the same set of variables in the Pacific (annual precipitation and distance to the nearest island), but not in the Atlantic (annual precipitation is a good predictor of native species turnover, but none of the variables considered in our study explained exotic species turnover). No signal of biotic interactions was detected at the insular community level.

Main conclusions
Successful invasion strategies may depend on a combination of factors specific to the region in question. In the Pacific, milder environments and the absence of natives on certain islands enable exotic ants to select the same types of environment as native ants. In the harsher Atlantic Ocean, however, native ant species are likely to be well adapted to local environmental conditions, making it harder for exotics to become established. Exotic ant species, therefore, potentially rely on other attributes to establish, such as a combination of tolerance to a wide range of environmental conditions and human-mediated colonization.
Original languageEnglish
Pages (from-to)2299-2310
Number of pages12
JournalJournal of biogeography
Volume46
Issue number10
Early online date8 Aug 2019
DOIs
Publication statusPublished - 1 Oct 2019

Keywords

  • ants
  • biodiversity
  • biotic interactions
  • environmental filtering
  • island biogeography
  • isolation by distance
  • multi-site generalised dissimilarity modelling
  • species richness
  • species turnover
  • zeta diversity

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