Alien species are continually introduced in most regions of the world, but not all survive and coexist with the resident native species Approaches analyzing the functional (or phylogenetic) similarity between invasive species and native communities are increasingly employed to infer the processes underlying successful invasions and to predict future invaders The relatively simple conceptual foundations have made these approaches very appealing and therefore widely used, often leading to confusion and hampering generalizations We undertook a comprehensive review and synthesis of the functional similarity approach in invasion community ecology to clarify its advantages and limitations, to summarize what has been learned thus far, and to suggest avenues for future improvement We first present the methodological state of the art and provide general guidelines Second, by organizing the published literature around seven key questions in invasion ecology we found cumulative evidence that: at large spatial scales phylogenetic relatedness of invasive and native species is a good predictor of invasion success, but a poor predictor of invasion impacts; at fine spatial scales, community resistance to invasion tends to increase with native species diversity and with similarity to the invaders, consistent with patterns emerging from biotic interactions In general, the processes filtering invaders appear to vary across species’ invasion stage and along environmental gradients Nonetheless, we found conflicting evidence for differences in community assembly processes between invasive and native species, and between the invader's native and adventive ranges Finally, we propose four important avenues for overcoming some of the identified methodological and conceptual limitations of the approach, in particular by integrating observational and experimental analyses and by explicitly considering species’ demographic rates and complex biotic interactions Although the functional similarity approach bears intrinsic limitations, it still offers many opportunities in invasion community ecology at large spatial scales

This article is protected by copyright All rights reserved

https://onlinelibrary.wiley.com/doi/pdf/10.1111/ecog.02446

The community ecology of invasive species: where are we and what\'s next?

Invasive alien species modify pollinator biodiversity and the services they provide that underpin ecosystem function and human well-being. Building on the Intergovernmental Science-Policy Platform for Biodiversity and Ecosystem Services (IPBES) global assessment of pollinators and pollination, we synthesize current understanding of invasive alien impacts on pollinators and pollination. Invasive alien species create risks and opportunities for pollinator nutrition, re-organize species interactions to affect native pollination and community stability, and spread and select for virulent diseases. Risks are complex but substantial, and depend greatly on the ecological function and evolutionary history of both the invader and the recipient ecosystem. We highlight evolutionary implications for pollination from invasive alien species, and identify future research directions, key messages and options for decision-making.

/pdf/risks-to-pollinators-and-pollination-from-invasive-alien-yey996dnwe.pdf

Risks to pollinators and pollination from invasive alien species.

The primary goal of invasive species management is to eliminate or reduce populations of invasive species. Although management efforts are often motivated by broader goals such as to reduce the negative impacts of invasive species on ecosystems and society, there has been little assessment of the consistency between population-based (e.g., removing invaders) and broader goals (e.g., recovery of ecological systems) for invasive species management. To address this, we conducted a comprehensive review of studies (N = 151) that removed invasive species and assessed ecological recovery over time. We found positive or mixed outcomes in most cases, but 31% of the time ecological recovery did not occur or there were negative ecological outcomes, such as increases in non-target invasive species. Ecological recovery was more likely in areas with relatively little anthropogenic disturbance and few other invaders, and for the recovery of animal populations and communities compared to plant communities and ecosystem processes. Elements of management protocols, such as whether invaders were eradicated (completely removed) versus aggressively suppressed (≥90% removed), did not affect the likelihood of ecological recovery. Our findings highlight the importance of considering broader goals and unintended outcomes when designing and implementing invasive species management programs.

https://www.srs.fs.usda.gov/pubs/ja/2018/ja_2018_klepzig_001.pdf

When does invasive species removal lead to ecological recovery? Implications for management success

Cryptic invasions: A review

Recent mercury levels and trends reported for North America suggest a mixed (positive/negative) outlook for the environmental mercury problem. Using one of the largest consistent monitoring data sets in the world, here we present long-term and recent mercury trends in Walleye, Northern Pike, and Lake Trout from the Province of Ontario, Canada, which contains about one-third of the world’s fresh water and covers a wide geographical area (1.5 and 3 times larger than France and Germany, respectively). Overall, the results indicate that the fish mercury levels either declined (0.01–0.07 μg/g decade) or remained stable between the 1970s and 2012. The rates of mercury decline were substantially greater (mostly 0.05–0.31 μg/g decade) during the 1970s/80s possibly in response to reductions in mercury emissions. However, Walleye and Pike levels have generally increased (0.01–0.27 μg/g decade) in recent years (1995–2012), especially for northern Ontario (effect sizes for differences between the two periods ranged f...

Fish mercury levels appear to be increasing lately: a report from 40 years of monitoring in the province of Ontario, Canada.

Generalized mutualisms are often predicted to be resilient to changes in partner identity. Variation in mutualism-related traits between native and invasive species however, can exacerbate the spread of invasive species (‘invasional meltdown’) if invasive partners strongly interact. Here we show how invasion by a seed-dispersing ant (Myrmica rubra) promotes recruitment of a co-introduced invasive over native ant-dispersed (myrmecochorous) plants. We created experimental communities of invasive (M. rubra) or native ants (Aphaenogaster rudis) and invasive and native plants and measured seed dispersal and plant recruitment. In our mesocosms, and in laboratory and field trials, M. rubra acted as a superior seed disperser relative to the native ant. By contrast, previous studies have found that invasive ants are often poor seed dispersers compared with native ants. Despite belonging to the same behavioural guild, seed-dispersing ants were not functionally redundant. Instead, native and invasive ants had strongly divergent effects on plant communities: the invasive plant dominated in the presence of the invasive ant and the native plants dominated in the presence of the native ant. Community changes were not due to preferences for coevolved partners: variation in functional traits of linked partners drove differences. Here, we show that strongly interacting introduced mutualists can be major drivers of ecological change.

/pdf/mutualism-between-co-introduced-species-facilitates-invasion-1tacmbascy.pdf

Jennifer M. Robinson

Papers

Mutualism between co-introduced species facilitates invasion and alters plant community structure

Assessment of fish mercury levels in the upper St. Lawrence River, Canada

Assessment of contaminant levels in fish from the Toronto waterfront area