Reciprocal human-natural system feedback loops within the invasion process

Abstract

Biological invasions are inextricably linked to how people collect, move, interact with and perceive non-native species. However, invasion frameworks generally do not consider reciprocal interactions between non-native species and people. Non-native species can shape human actions via beneficial or detrimental ecological and socioeconomic effects and people, in turn, shape invasions through their movements, behaviour and how they respond to the collection, transport, introduction and spread of non-natives. The feedbacks that stem from this ‘coupled human and natural system’ (CHANS) could therefore play a key role in mitigating (i.e. negative feedback loops) or exacerbating (i.e. positive feedback loops) ongoing and future invasions. We posit that the invasion process could be subdivided into three CHANS that span from the source region from which non-natives originate to the recipient region in which they establish and spread. We also provide specific examples of feedback loops that occur within each CHANS that have either reduced or facilitated new introductions and spread of established non-native species. In so doing, we add to exisiting invasion frameworks to generate new hypotheses about human-based drivers of biological invasions and further efforts to determine how ecological outcomes feed back into human actions.

MAcroecological Framework for Invasive Aliens (MAFIA): disentangling large-scale context dependence in biological invasions

“…Another key notion is that the macroecological processes of biological invasions are underpinned both by biological and environmental characteristics (that are used to explain the distribution, abundance, and richness of alien species in their native ranges), and by human factors that influence the probability and magnitude of transport and introduction of alien species, and whether, where, and when a species is given the opportunity to succeed. Such human factors include the origin, destination, and means by which species are transported (Sinclair et al 2020), the locations, identities, numbers of introduction events, numbers of species (colonisation pressure; Lockwood et al 2009), individuals or propagules (propagule pressure; Lockwood et al 2005) being introduced, and residence time (Forcella and Wood 1984;Rejmánek 2000;Pyšek and Jarošík 2005;Wilson et al 2007;Williamson et al 2009;Gassó et al 2010), as well as spatial (by widespread dissemination or abundant plantings; Hanspach et al 2008) and temporal (by long history of cultivation; Rouget and Richardson 2003) variation in these factors.…”

“…It therefore follows that, at the global level, observed aliens are a subsample of the world's native species pool (though exceptions could occur where alien species hybridise and speciate in their new ranges; Ellstrand and Schierenbeck 2000;Levin 2003;Flores-Moreno et al 2015;Brandenburger et al 2019). Which species from this pool get entrained on the invasion pathway depends on the interaction of the socioeconomic motivations or determinants for translocation, and the distribution and characteristics of the species (Hulme et al 2008;Essl et al 2015;Sinclair et al 2020). These latter features affect the probability that a species is selected (deliberately or otherwise) for transport.…”

“…Our understanding of the role of macroecological processes in invasions can only advance if we are able to build a mechanistic framework that incorporates the most relevant factors (event, location, species) and their interactions, as well as biases that arise through human selectivity along the invasion sequence, resulting from the fact that invasions are part of a 'coupled human and natural system' (Sinclair et al 2020, see also Howard 2019). We believe that the MAFIA is helpful for conceptualising these issues, by explicitly identifying the pathway along which alien macroecological patterns develop, and how biases in observed patterns may be inserted by this pathway.…”

The Urban River Syndrome: Achieving Sustainability Against a Backdrop of Accelerating Change

“…A typical feature of urban rivers is an increasing number of non-native species [ 111 ]. Much like other similar river systems globally, the Thames catchment is home to a large and increasing number of non-native species [ 37 ].…”

The effect of cross-boundary management on the trajectory to commonness in biological invasions

“…Using such criteria would allow for global assessments of the state of biological invasions, as is done, for example for species becoming rare with the IUCN Red List of Threatened Species (IUCN 2019). From an applied management perspective, defining the thresholds based on the management capacity of countries may also be appropriate, and could vary in space and time based on the management capacities of a country, the development of novel management methods, and an understanding of how the 'coupled human and natural system' affects invasions (Sinclair et al 2020).…”