Functional traits of indigenous and exotic ground‐dwelling arthropods show contrasting responses to land‐use change in an oceanic island, Terceira, Azores

Abstract

Aim: Land-use change typically goes hand in hand with the introduction of exotic species, which mingle with indigenous species to form novel assemblages. Here, we compare the functional structure of indigenous and exotic elements of ground-dwelling arthropod assemblages across four land-uses of varying management intensity.Location: Terceira Island (Azores, North Atlantic). Methods:We used pitfall traps to sample arthropods in 36 sites across the four landuses and collated traits related to dispersal ability, body size and resource use. For both indigenous and exotic species, we examined the impact of land-uses on trait diversity and tested for the existence of non-random assembly processes using null models. We analysed differences in trait composition among land-uses for both indigenous and exotic species with multivariate analyses. We used point-biserial correlations to identity traits significantly correlated with specific land-uses for each element. Results:We recorded 86 indigenous and 116 exotic arthropod species. Under highintensity land-use, both indigenous and exotic elements showed significant trait clustering. Trait composition strongly shifted across land-uses, with indigenous and exotic species being functionally dissimilar in all land-uses. Large-bodied herbivores dominated exotic elements in low-intensity land-uses, while small-bodied spiders dominated exotic elements in high-intensity land-uses. In contrast, with increasing land-use intensity, indigenous species changed from functionally diverse to being dominated by piercing and cutting herbivores.

Comparative responses of termite functional and taxonomic diversity to land‐use change

“…Heterogeneous primary forests have greater structural complexity and variety of resources than do rubber plantations, as well as more varied microclimates and microhabitats, which allows for the coexistence of more functional traits and species in the community. By contrast, rubber plantations may filter for a restricted set of functional strategies due to the uniform environmental conditions, leading to functional homogenisation where termite species fulfil similar functional roles (Olden & Rooney, ; Rigal et al ., ). Our results provide additional evidence that uniform habitat constraints operate as filters, allowing only species with similar traits to assemble (Puttker et al ., ).…”

“…Functional trait‐based approaches have already been reported for some soil invertebrates like ants, Collembola, and Isopoda, which provided a useful insight into how species respond to land‐use changes (Liu et al ., ; Rigal et al ., ) and climate change (Dias et al ., ). Meanwhile, land‐use changes also are considered to act as an important ecological filter that changes the functional traits of invertebrates.…”

Differential temporal beta‐diversity patterns of native and non‐native arthropod species in a fragmented native forest landscape

“…Many non-native arthropod species in the Azores are adapted to human land-uses (Borges et al 2008, Rigal et al 2018, and thus we would expect there be a large number, and thus high potential for mass effects (Shmida and Wilson 1985), of non-natives in the disturbed landscapes surrounding the fragments (see also Borges et al 2008). The Azores has undergone substantial land use change since human colonisation of the archipelago (Triantis et al 2010), and native forest fragments in the Azores are characterised by hard boundaries, i.e.…”

Hotspots of biodiversity and ecosystem services: the Outermost Regions and Overseas Countries and Territories of the European Union

“…alien plants can increase microbial activity) and introduced natural enemies can control pests (Vilà et al 2011). Also relevant was the result obtained by Rigal et al 2018 on the impact of land-use changes on the functional role of exotic and native arthropods in the Azores. The main finding was that there is a potential functional complementarity between indigenous and exotic species, which means that, in agricultural landscapes, exotic species might provide and maintain key ecosystem functions (Rigal et al 2018).…”

“…Also relevant was the result obtained by Rigal et al 2018 on the impact of land-use changes on the functional role of exotic and native arthropods in the Azores. The main finding was that there is a potential functional complementarity between indigenous and exotic species, which means that, in agricultural landscapes, exotic species might provide and maintain key ecosystem functions (Rigal et al 2018). However, pollinator native species may also contribute to pollination services in human-made habitats and may promote the spread of invasive plants, as seen in the Azores (Picanço et al 2017b).…”