Human-Mediated Dispersal and the Rewiring of Spatial Networks

Bullock, James M.; Bonte, Dries; Pufal, Gesine; Carvalho, Carolina da Silva; Chapman, Daniel S.; García, Cristina; García, Daniel García; Matthysen, Erik; Delgado, Maria M.

doi:10.1016/j.tree.2018.09.008

Cited by 130 publications

(119 citation statements)

References 99 publications

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“…Among these, human activities clearly play a major role. Firstly, humans are responsible for the propagule pressure by which species are introduced into new non-native regions and dispersed regionally from established non-native populations (Bullock et al, 2018;Chapman, Purse, Roy, & Bullock, 2017;Lockwood, Cassey, & Blackburn, 2005). Secondly, humans cause the ecosystem disturbance and resource inputs that are thought to lessen biotic resistance of recipient communities to establishment of non-native species (Davis, Grime, & Thompson, 2001).…”

Section: Introductionmentioning

confidence: 99%

Invasion of freshwater ecosystems is promoted by network connectivity to hotspots of human activity

Chapman

Gunn

Pringle

et al. 2019

Global Ecol Biogeogr

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Aim Hotspots of human activity are focal points for ecosystem disturbance and non‐native introduction, from which invading populations disperse and spread. As such, connectivity to locations used by humans may influence the likelihood of invasion. Moreover, connectivity in freshwater ecosystems may follow the hydrological network. Here we tested whether multiple forms of connectivity to human recreational activities promotes biological invasion of freshwater ecosystems. Location England, UK. Time period 1990–2018. Major taxa studied One hundred and twenty‐six non‐native freshwater birds, crustaceans, fish, molluscs and plants. Methods Machine learning was used to predict spatial gradients in human recreation and two high risk activities for invasion (fishing and water sports). Connectivity indices were developed for each activity, in which human influence decayed from activity hotspots according to Euclidean distance (spatial connectivity) or hydrological network distance (downstream, upstream and along‐channel connectivity). Generalized linear mixed models identified the connectivity type most associated to invasive species richness of each group, while controlling for other anthropogenic and environmental drivers. Results Connectivity to humans generally had stronger positive effects on invasion than all other drivers except recording effort. Recreation had stronger influence than urban land cover, and for most groups high risk activities had stronger effects than general recreation. Downstream human connectivity was most important for invasion by most of the groups, potentially reflecting predominantly hydrological dispersal. An exception was birds, for which spatial connectivity was most important, possibly because of overland dispersal capacity. Main conclusions These findings support the hypothesis that freshwater invasion is partly determined by an interaction between human activity and species dispersal in the hydrological network. By comparing alternative connectivity types for different human activities, our approach could enable robust inference of specific pathways and spread mechanisms associated with particular taxa. This would provide evidence to support better prioritization of surveillance and management for invasive non‐native species.

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Section: Introductionmentioning

confidence: 99%

Invasion of freshwater ecosystems is promoted by network connectivity to hotspots of human activity

Chapman

Gunn

Pringle

et al. 2019

Global Ecol Biogeogr

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“…Bullock et al (2018) provided a new conceptual overview of HMD as comprising a suite of direct and indirect influences on dispersal of all taxa. As described by Bullock et al (2018), HMD has a hierarchical classification, being split into human‐vectored dispersal (HVD) and human‐altered dispersal (HAD). Here, we take that classification and in Figure 1 and the following describe examples of how it applies to plants specifically.…”

Section: Types Of Human‐mediated Plant Dispersalmentioning

confidence: 99%

“…It is less commonly recognised that human activities have a variety of effects on dispersal, and the impacts of this changed dispersal on vegetation dynamics are rarely considered. Bullock et al (2018) reviewed the range of direct and indirect effects of humans on dispersal of plants and animals, and organised them under the general term, human‐mediated dispersal (HMD). That review showed the fundamental ways by which ecological processes can be changed by HMD, particularly through altered dispersal patterns, which are species‐specific and relate to species’ traits.…”

Section: Introductionmentioning

confidence: 99%

Human‐mediated dispersal as a driver of vegetation dynamics: A conceptual synthesis

Bullock

Pufal

2020

J Vegetation Science

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Question Human‐mediated dispersal (HMD) comprises human‐vectored dispersal (HVD; direct movement of organisms by people) and human‐altered dispersal (HAD; indirect change in dispersal patterns through human alteration of ecosystems). In the vegetation dynamics literature, human influence has primarily been studied in terms of perturbations to natural communities. Except for non‐native invasions, the role of HMD in vegetation dynamics has rarely been considered. Given the increasing human population and its pervasive impacts across the world, it is necessary to understand the different ways in which HMD drives changes in vegetation dynamics. Importantly how large are these influences and how do they disrupt natural processes? Method We reviewed studies examining aspects of HMD in relation to vegetation dynamics and used the broader literature to inform a conceptual synthesis of the impacts of HMD on vegetation dynamics. Results & Conclusions The propensity to be affected by HMD varies among species, and this is related to seed and plant traits. Together, these effects combine to determine whether HMD disrupts or enhances seed dispersal into a community. The ultimate consequences of changed arrival of seeds into a community are determined by the strength of the environmental and biotic filters, which govern the establishment and persistence of species. The effect of accidental HVD depends whether it follows the same rules as for natural dispersal; indeed humans might replace lost natural dispersers and thus enhance community resilience. Intentional HVD through sowing or planting will generally be highly disruptive especially as it often involves associated management. Traditionally, HAD has been considered to disrupt vegetation dynamics through, e.g., fragmentation or loss of natural dispersers. However, an HMD perspective can inform actions related to HAD that increase resilience, e.g., green infrastructure or vegetation management. Our framework encourages researchers to consider HMD holistically, to understand how the increasing human footprint might affect vegetation dynamics and resilience under future change.

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“…This higher diversity then makes the local 318 communities more resistant to invasions. It is thus a "to kill two birds with one 319 stone" situation: appropriate management of spatial networks, and the maintenance 320 of spatial networks per se, not only leads to more diverse local communities and 321 maintains diversity as such, but also makes these communities more resistant to 322 biological invasions (Harvey et al 2016, Bullock et al 2018. 323…”

Section: ): the Invasion Success Follows A Reverse Hump-shaped Relatmentioning

confidence: 99%

Patch size distribution and network connectivity affect species invasion dynamics in dendritic networks

Holenstein

Harvey

Altermatt

2020

Preprint

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Biological invasions are globally affecting ecosystems, causing local species loss and altering ecosystem functioning. Understanding the success and unfolding of such biological invasions is thus of high priority. Both local properties and the spatial network structure have been shown to be determinants of invasion success, and the identification of spatial invasion hubs directly promoting invasion dynamics is gaining attention. Spatial dynamics, however, could also indirectly alter invasion success by shaping local community structure: in many ecosystems, such as riverine networks, regional properties such as patch size distribution are known drivers of local community structures, which themselves may affect the establishment success of invading species. Using microcosm experiments in dendritic networks, we disentangled how patch size distribution and dispersal along specific network topologies shaped local communities, and, subsequently, affected the establishment success of invading species. We find that inherent patch size distributions shaped composition and diversity of local communities, and, subsequently, modulated invasion success. Specifically, the relationship between local diversity and invasion success changed across an increasing patch size gradient from a negative to a positive correlation, while overall increasing patch size reduced invasion success. Connectivity did not have a direct effect on invasion success but indirectly affected invasions by shaping diversity patterns in the whole network. Our results emphasize the relevance of indirect, landscape-level effects on species invasions, which need to be considered in the management of spatial habitat networks.

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Human-Mediated Dispersal and the Rewiring of Spatial Networks

Cited by 130 publications

References 99 publications

Invasion of freshwater ecosystems is promoted by network connectivity to hotspots of human activity

Invasion of freshwater ecosystems is promoted by network connectivity to hotspots of human activity

Human‐mediated dispersal as a driver of vegetation dynamics: A conceptual synthesis

Patch size distribution and network connectivity affect species invasion dynamics in dendritic networks

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