Introduced plants as novel Anthropocene habitats for insects

Abstract

Major environmental changes in the history of life on Earth have given rise to novel habitats, which gradually accumulate species. Human‐induced change is no exception, yet the rules governing species accumulation in anthropogenic habitats are not fully developed. Here we propose that nonnative plants introduced to Great Britain may function as analogues of novel anthropogenic habitats for insects and mites, analysing a combination of local‐scale experimental plot data and geographic‐scale data contained within the Great Britain Database of Insects and their Food Plants. We find that novel plant habitats accumulate the greatest diversity of insect taxa when they are widespread and show some resemblance to plant habitats which have been present historically (based on the relatedness between native and nonnative plant species), with insect generalists colonizing from a wider range of sources. Despite reduced per‐plant diversity, nonnative plants can support distinctive insect communities, sometimes including insect taxa that are otherwise rare or absent. Thus, novel plant habitats may contribute to, and potentially maintain, broader‐scale (assemblage) diversity in regions that contain mixtures of long‐standing and novel plant habitats.

Indigenous plants promote insect biodiversity in urban greenspaces

“…While we have emphasized the critical role of indigenous plants, we have also shown that indigenous insects are being found in association with a wide array of regionally native and nonnative plants. Thus, our study supports the idea that urban environments facilitate novel resource utilization by indigenous insects (Padovani et al 2020, Valentine et al 2020). Future experimental work on this topic is needed to clarify to what extent these associations reflect host shifting patterns unique to urban environments and to fully understand the opportunities and risks provided by novel urban resources.…”

Non‐native palms (Arecaceae) as generators of novel ecosystems: A global assessment

“…Novel ecosystems are on the rise, in large part driven by introductions of non‐native species, but also promoted by ongoing global warming, increased atmospheric carbon dioxide (CO 2 ) and land use change (Feng et al., 2014; Hobbs et al., 2009; Perring & Ellis, 2013). The new species assemblages and ecosystem functions of these novel ecosystems are likely to alter ecosystem services (Collier, 2014; Evers et al., 2018; Hobbs et al., 2009; Millenium Ecosystem Assessment, 2005) may threaten native species (Bellard, Genovesi, & Jeschke, 2016; Pyšek et al., 2012) but could also generate new habitats for native species (Padovani, Salisbury, Bostock, Roy, & Thomas, 2020). An improved understanding of the functioning of novel ecosystems to these increasingly widespread natural environments should clearly be an important research priority (e.g.…”

Contrasting effects of tree origin and urbanization on invertebrate abundance and tree phenology

“…In both studies, nonnative plants also hosted significantly lower abundances of invertebrates in addition to an overall lower diversity (Burghardt and Tallamy 2015, Padovani et al. 2020). Other studies have similarly found that invertebrates linked to nonnative plants typically are generalists rather than specialists (Brändle et al.…”

“…In general, the time since introduction of a new plant species has been found to be positively correlated to the arthropod abundance and diversity that it hosts, meaning that nonnative plants introduced earlier support higher insect abundance than more recent introductions (Br€ andle et al 2008, Padovani et al 2020. Furthermore, nonnative plants closely related to local species (congeneric species) generally host more invertebrates both in terms of abundance and diversity compared to less closely related nonnatives (Burghardt et al 2010, Burghardt and Tallamy 2015, Padovani et al 2020. This suggest that the difference in invertebrate abundance and diversity hosted by nonnative and native vegetation can be explained by a lack of coevolutionary history, which shapes relations between many pollinators and herbivores and their host plants (Ehrlich and Raven 1964).…”

“…However, it has been suggested that nonnative plants may create novel habitats for invertebrates and could therefore increase diversity on a regional level. For example, Padovani et al (2020) showed that novel nonnative plants were associated with a distinct arthropod fauna, rather than a subset of the species found on native plants. On the other hand, Burghardt and Tallamy (2015) found the opposite pattern: invertebrates found on novel nonnative plants were not host specific, but generalists found on native plants as well.…”