Can the native faunal communities be restored from removal of invasive plants in coastal ecosystems? A global meta‐analysis

Abstract

Coastal ecosystems worldwide are being threatened by invasive plants in the context of global changes. However, how invasive plants influence native faunal communities and whether native faunal communities can recover following the invader removals/controls across global coastal ecosystems are still poorly understood. Here, we present the first global meta‐analysis to quantify the impacts of Spartina species invasions on coastal faunal communities and further to evaluate the outcomes of Spartina species removals on faunal community recovery based on 74 independent studies. We found that invasive Spartina species generally decreased the biodiversity (e.g., species richness), but increased coastal faunal abundance (e.g., individual number) and fitness (e.g., biomass), though the effect on abundance was insignificant. The pattern of influence was strongly dependent on habitat types, faunal taxa, trophic levels, and feeding types. Specifically, Spartina species invasion of mudflats caused greater impacts than invasion of vegetated habitats. Insects and birds at higher trophic levels were strongly affected by invasive Spartina, indicating that invasive plant effects can cascade upward along the food chain. Additionally, impacts of Spartina invasions were more obvious on food specialists such as herbivores and carnivores. Furthermore, our analyses revealed that invader removals were overall beneficial for native faunal communities to recover from the displacement caused by Spartina invasions, but this recovery process depended on specific removal measure and time. For example, the long‐term waterlogging had strong negative impacts on faunal recovery, so it should not be encouraged. Our findings suggest that invasive plants could have contrasting effects on functional responses of native faunal communities. Although invasive plant removals could restore native faunal communities, future functional restorations of invaded ecosystems should take the legacy effects of invasive species on native communities into account. These findings provide insightful implications for future scientific controls of invasive species and ecosystem restoration under intensifying global changes.

Does compensatory mitigation restore food webs in coastal wetlands? A terrestrial arthropod case study on the Upper Texas Coast

“…In this study, plant and terrestrial arthropod communities were distinctly different between restored and reference areas, and those differences contributed to dissimilarity in food web structure among habitat types. Terrestrial arthropods play important roles in controlling productivity and supporting higher trophic levels, including fish and avian predators (Post and Greenlaw, 2006;Batzer and Wu, 2020;Ning et al, 2021). In some cases, terrestrial arthropod abundances rapidly re-establish following habitat restoration (Gratton and Denno, 2005;David et al, 2016), but restored assemblages are often dissimilar in terms of diversity and distribution among trophic guilds (Pétillon et al, 2014;Ning et al, 2021;Farfán-Beltrán et al, 2022).…”

“…However, the response of lower trophic levels to compensatory restoration is usually assumed but seldom quantified and rarely considered in assessments of restoration success (Weinstein et al, 2005;Loch et al, 2020). In coastal marshes, terrestrial arthropods (insects, spiders, and their kin) are important grazers and prey items in food webs (Post and Greenlaw, 2006;Batzer and Wu, 2020;Ning et al, 2021). Many of these organisms are closely associated with marsh plants, and so faunal use of restored areas may also be affected by marsh plant identity (Talley and Levin, 1999;Wu et al, 2008).…”

“…Many of these organisms are closely associated with marsh plants, and so faunal use of restored areas may also be affected by marsh plant identity (Talley and Levin, 1999;Wu et al, 2008). For example, insect diversity and abundance are often lower in wetlands invaded by Spartina alterniflora (Ning et al, 2021). Conversely, restoration of S. alterniflora within its native range can increase arthropod abundance and diversity (Gratton and Denno, 2005).…”

“…For generalist species, plant identity may be less important than plant cover or density (Guiden et al, 2021), though plant structure may be linked to habitat suitability for some predators such as web-building spiders. In some cases, terrestrial arthropod assemblages and trophic interactions recover following habitat restoration (Gratton and Denno, 2006;Watts and Didham, 2006), but in others, food webs can be slow to approach reference conditions (Wozniak et al, 2006;Ning et al, 2021;Wu et al, 2021). On a decadal scale, the character of the food web changes over time, shifting from detrital-based to herbivore-driven as the restored site ages (Schrama et al, 2012).…”

Effects of ecological restoration on soil biogenic elements and their ecological stoichiometry in the Yellow River Delta, China

“…More than ten big ecological restoration projects have been performed in the Yellow River Delta since 2020, including Suaeda salsa restoration, Spartina alterniflora removal, hydrological connectivity enhancement, etc. (Liu et al, 2018;Zhao et al, 2020;Jiang et al, 2021;Ning et al, 2021). Given the critical role of the Yellow River Delta, understanding the effects of ecological restoration on the soil biogenic elements and ecological stoichiometry becomes an imperative task.…”