Quantifying levels of biological invasion: towards the objective classification of invaded and invasible ecosystems

By Jane A. Catford, Peter Vesk, D. Richardson, Petr Pyšek. Global Change Biology, 2011

286 citations recorded by the source corpus.

Biological invasions are a global phenomenon that threatens biodiversity, and few, if any, ecosystems are free from alien species. The outcome of human‐mediated introductions is affected by the invasiveness of species and invasibility of ecosystems, but research has primarily focused on defining, characterizing and identifying invasive species; ecosystem invasibility has received much less attention. A prerequisite for characterizing invasibility is the ability to compare levels of invasion across ecosystems. In this paper, we aim to identify the best way to quantify the level of invasion by nonnative animals and plants by reviewing the advantages and disadvantages of different metrics. We explore how interpretation and choice of these measures can depend on the objective of a study or management intervention. Based on our review, we recommend two invasion indices and illustrate their use by applying them to two case studies. Relative alien species richness and relative alien species abundance indicate the contribution that alien species make to a community. They are easy to measure, can be applied to various taxa, are independent of scale and are comparable across regions and ecosystems, and historical data are often available. The relationship between relative alien richness and abundance can indicate the presence of dominant alien species and the trajectory of invasion over time, and can highlight ecosystems and sites that are heavily invaded or especially susceptible to invasion. Splitting species into functional groups and examining invasion patterns of transformer species may be particularly instructive for gauging effects of alien invasion on ecosystem structure and function. Establishing standard, transparent ways to define and quantify invasion level will facilitate meaningful comparisons among studies, ecosystem types and regions. It is essential for progress in ecology and will help guide ecosystem restoration and management.

Subfields: Ecology, Insect Science, Nature and Landscape Conservation

View Paper: https://www.semanticscholar.org/paper/7cfb481fcb8cfaf7e3323309ac8c902532dbc25e

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Citations in the corpus

MAcroecological Framework for Invasive Aliens (MAFIA): disentangling large-scale context dependence in biological invasions (2020, background): “(or vulnerability to invasion) of a region, community or habitat and a simple number of invasive species it harbours; for the latter the term ‘level of invasion’ has become broadly used (Chytrý et al. 2005; Hierro et al. 2005; Catford et al. 2012).”
Species and environmental characteristics point to flow regulation and drought as drivers of riparian plant invasion (2014, background): “High propagule availability can increase colonisation success across all environmental conditions, but it is particularly influential in areas with high resource availability (Catford et al., 2012a), which might occur if the abundance of, and uptake by, natives species declines (Davis et al., 2000).”
Does the biogeographic origin of species matter? Ecological effects of native and non‐native species and the use of origin to guide management (2016, background): “The rate of species introductions and the ability of non-natives to become dominant in diverse ecosystems have changed the composition of many ecological communities (Catford et al. 2012b; Seabloom et al. 2013, 2015; Dornelas et al. 2014).”
Current mismatch between research and conservation efforts: The need to study co-occurring invasive plant species (2013, background): “, 2008a) and quantifying consistent metrics for measuring invasion level in terms of abundance, evenness, and richness of invasives (Catford et al., 2012).”
Two co-occurring invasive woody shrubs alter soil properties and promote subdominant invasive species (2014, background): “Habitats vary greatly in their level of invasion (Chytr y et al. 2008b; Catford et al. 2012) owing to habitat characteristics such as distance from propagule sources or the competitive ability of the species within the habitat.”
Invasive grasses: A new perfect storm for forested ecosystems? (2020, background): “Characterizing forest resilience to grass invasion will require information about invasion levels, propagule pressure and dispersal vectors, and characteristics of the newly introduced species, as well as complex relationships between the invading species and the biotic and abiotic environment of th”
Niche differentiation among invasive crayfish and their impacts on ecosystem structure and functioning (2014, background): “Despite recent progress in invasion biology (e.g. Johnson et al., 2009; Catford et al., 2012; Sanders et al., 2003), our knowledge regarding specific ecological impacts, and the mechanisms behind them, remain limited for most invaders.”