Improving Ecological Restoration to Curb Biotic Invasion—A Practical Guide

Abstract

Common practices for invasive species control and management include physical, chemical, and biological approaches. The first two approaches have clear limitations and may lead to unintended (negative) consequences, unless carefully planned and implemented. For example, physical removal rarely completely eradicates the targeted invasive species and can cause disturbances that facilitate new invasions by nonnative species from nearby habitats. Chemical treatments can harm native, and especially rare, species through unanticipated side effects. Biological methods may be classified as biocontrol and the ecological approach. Similar to physical and chemical methods, biocontrol also has limitations and sometimes leads to unintended consequences. Therefore, a relatively safer and more practical choice may be the ecological approach, which has two major components: (1) restoration of native species and (2) biomass manipulation of the restored community, such as selective grazing or prescribed burning (to achieve and maintain viable population sizes). Restoration requires well-planned and implemented planting designs that consider alpha-, beta-, and gamma-diversity and the abundance of native and invasive component species at local, landscape, and regional levels. Given the extensive destruction or degradation of natural habitats around the world, restoration could be most effective for enhancing ecosystem resilience and resistance to biotic invasions. At the same time, ecosystems in human-dominated landscapes, especially those newly restored, require close monitoring and careful intervention (e.g., through biomass manipulation), especially when successional trajectories are not moving as intended. Biomass management frequently uses prescribed burning, grazing, harvesting, and thinning to maintain overall ecosystem health and sustainability. Thus, the resulting optimal, balanced, and relatively stable ecological conditions could more effectively limit the spread and establishment of invasive species. Here we review the literature (especially within the last decade) on ecological approaches that involve biodiversity, biomass, and productivity, three key community/ecosystem variables that reciprocally influence one another. We focus on the common and most feasible ecological practices that can aid in resisting new invasions and/or suppressing the dominance of existing invasive species. We contend that, because of the strong influences from neighboring areas (i.e., as exotic species pools), local restoration and management efforts in the future need to consider the regional context and projected climate changes.

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

“…In the Great Plains, sites have low native diversity (Table ) and neighbor large swaths of agricultural lands, resulting in low biotic resistance, high propagule pressure and regular disturbance in surrounding areas, which may cause the high probability of non‐native occurrence we observed. Managing post‐disturbance is a well‐supported recommendation for reducing invasions (Hobbs & Huenneke ; Guo et al ), and our study confirms that anthropogenically affected areas require more management of incoming non‐native species with the potential to become invasive.…”

“…Despite inconsistent evidence for biotic resistance, natural resource managers have adopted the approach of conserving and restoring native plant diversity in hopes of reducing invasions (Funk et al ; Nimmo et al ; Guo et al ). This strategy aims to prevent invasions during the establishment stage – before some non‐native species spread (Blackburn et al ) and eradication becomes less likely.…”

Forest regrowth reduces richness and abundance of invasive alien plant species in community managed Shorea robusta forests of central Nepal

“…These results have direct implications for the management of IAPS in forests of Nepal. Ecosystem based management of IAPS, i.e., prevention and control of IAPS though proper management of habitat/ecosystem, has been increasingly felt necessary as the number of IAPS and the areas of natural ecosystems that they have invaded are continuously increasing (Guo et al 2018). Thousands of small to large patches of forests in Nepal are being managed by local communities, and, as a result of their management, the ecological conditions of forests have improved substantially in terms of vegetation cover, tree stocking, ecosystem services, and biodiversity conservation (Shrestha et al 2010;Thapa-Magar andShrestha 2015, Oldekop et al 2019).…”

A Subcontinental Analysis of Forest Fragmentation Effects on Insect and Disease Invasion

“…This observation may largely reflect anthropogenic influences, including increased propagule pressure associated with human activities. These findings from regional and continental-scale research will help future efforts in managing forest pest invasions, and in guiding ongoing and planned forest restorations [37].…”