Biotic resistance to invasion is ubiquitous across ecosystems of the United States

Beaury, E.M., Finn, J.T., Corbin, J.D., Barr, V. and Bradley, B.A. (2020), Biotic resistance to invasion is ubiquitous across ecosystems of the United States. Ecol Lett, 23: 476-482. doi:10.1111/ele.13446 PDF.

Summary

Non-native plant invasions are driving a dramatic loss in native biodiversity worldwide, and one of the consequences of biodiversity loss is the further establishment and spread of invasive species. As invasive species shift with climate change, it is more important than ever to understand what environmental and human factors bolster native communities against invasions, and which ecosystems are most vulnerable to degradation. Using continental scale data of nearly 25,000 surveys collected by the National Park Service, Beaury et al. (2020) identified the drivers of non-native species occurrence across ecosystems of the United States. They found that across environments, non-native plants were less likely to occur in communities with high numbers of native species. However, the resistance of native communities to invasion was lower closer to human dominated landscapes, in warmer climates, and in communities characterized by herbaceous native species (communities dominated by trees and shrubs had fewer non-native species). This study provides evidence that conservation and restoration activities that promote native biodiversity can reduce non-native species occurrence and establishment, thereby reducing the likelihood of invasion. However, the strength of resistance to invasion varies across different ecological, human, and climatic contexts.

Take home points

  • Non-native species are less likely to occur in communities with high numbers of native species

  • At local scales, non-native species are more likely to occur near agricultural and urban lands, in warmer climates, and in communities dominated by herbaceous species. These areas are more vulnerable to invasion.

Management implications

  • Removing invasive plants and conserving native biodiversity may both be effective strategies for reducing invasions.

  • Conserving and restoring high numbers of native plant species can reduce the likelihood of non-native species establishment because diverse native communities are less likely to be invaded.

  • The strength of invasion resistance varies with habitat. More vulnerable habitats (grasslands and meadows) may need more management than habitats with higher resistance to invasion (forests and woodlands).

Keywords

Competitiveness; Range Expansion; Terrestrial habitat, Invasive plant; Biotic resistance