Jennifer G Howeth

• Ph.D. Ecology
• Deputy Center Director, SMARC at U.S. Fish and Wildlife Service

Biological invasions driven by international trade heighten the urgency for development of invasion risk models, as the traits and parameters that consistently predict successful invasion remain unresolved. For four regions of North America that include parts of the United States and Canada (Sacramento-San Joaquin River Basins, Lower Colorado River...

Metacommunity theory predicts that the relative importance of regional and local processes structuring communities will change over ecological succession. Determining effects of these processes on taxonomic and evolutionary diversity in spatially structured freshwater habitats of different successional stages may greatly improve understanding of th...

Managing invasive species with prevention and early‐detection strategies can avert severe ecological and economic impacts. Horizon scanning, an evidence‐based process combining risk screening and consensus building to identify threats, has become a valuable tool for prioritizing invasive species management and prevention. We assembled a working gro...

Impacts of omnivorous invaders on community structure and biomass of multiple trophic levels are often complex and poorly understood. Responses to omnivory may vary by trophic level and depend upon regional connectivity in the invaded landscape. Here, we tested for differences in multi-trophic planktonic species diversity and ecosystem attributes a...

Aim Impacts of non‐native species have motivated development of risk assessment tools for identifying introduced species likely to become invasive. Here, we develop trait‐based models for the establishment and impact stages of freshwater fish invasion, and use them to screen non‐native species common in international trade. We also determine which...

Ecological succession explored at the secondary and postsecondary level is often limited to terrestrial ecosystems. The emphasis is traditionally placed on how deforestation leads to ecological succession. However, aquatic ecological succession is just as important and allows for many connections to be made with other ecological concepts. Successio...

Metacommunity theory predicts that the relative importance of regional and local processes structuring communities will change over time since initiation of community assembly. Determining effects of these processes on species and trait diversity over succession remains largely unaddressed in metacommunity ecology to date, yet could confer an impro...

The complexity of ecological systems is a major challenge for practitioners and decision-makers who work to avoid, mitigate and manage environmental change. Here, we illustrate how metaecology – the study of spatial interdependencies among ecological systems through fluxes of organisms, energy, and matter – can enhance understanding and improve man...

Mechanistic insights from invasion biology indicate that propagule pressure of non‐native species and native community structure can independently influence establishment success. The role of native community connectivity via species dispersal and its potential interaction with propagule pressure on invasion success in metacommunities, however, rem...

The complexity of ecological systems is a major challenge for practitioners and decision-makers who work to avoid, mitigate and manage environmental change. Here, we illustrate how metaecology - the study of spatial interdependencies among ecological systems through fluxes of organisms, energy, and matter - can enhance understanding and improve man...

Recent studies indicate that diversity–invasibility relationships can depend on spatial scale, but the contributing role of native species dispersal among local communities in mediating these relationships remains unaddressed. Metacommunity ecology highlights the effects of species dispersal rates on local diversity, thereby suggesting that native...

Metacommunity theory suggests that species diversity can depend upon the time since initiation of community assembly, or habitat age, as the relative influence of regional and local structuring processes changes over succession. There are, however, few studies that evaluate the role of habitat age in structuring species richness (diversity–age) ove...

Risk analysis of species invasions links biology and economics, is increasingly mandated by international and national policies, and enables improved management of invasive species. Biological invasions proceed through a series of transition probabilities (i.e., introduction, establishment, spread, and impact), and each of these presents opportunit...

Intraspecific phenotypic variation can strongly impact community and ecosystem dynamics. Effects of intraspecific variation in keystone species have been shown to propagate down through the food web by altering the adaptive landscape for other species and creating a cascade of ecological and evolutionary change. However, similar bottom-up eco-evolu...

Background/Question/Methods A global increase in international trade has led to an increase in both intentional and unintentional transport of nonindigenous species. Because of this, there is an increased likelihood that more species will become established and/or invasive outside of their native geographic ranges. We evaluated the performance of...

Evolutionary diversification within consumer species may generate selection on local ecological communities, affecting prey community structure. However, the extent to which this niche construction can propagate across food webs and shape trait variation in competing species is unknown. Here, we tested whether niche construction by different life-h...

Intentional introductions of nonindigenous fishes are increasing globally. While benefits of these introductions are easily quantified, assessments to understand the negative impacts to ecosystems are often difficult, incomplete, or absent. Grass carp (Ctenopharyngodon idella) was originally introduced to the United States as a biocontrol agent, an...

Contemporary insights from evolutionary ecology suggest that population divergence in ecologically important traits within predators can generate diversifying ecological selection on local community structure. Many studies acknowledging these effects of intraspecific variation assume that local populations are situated in communities that are uncon...

Recent interest in the ecological drivers of compensatory and synchronous population dynamics has provided an improved yet incomplete understanding of local and regional population oscillations in response to variable environments. Here, we evaluate the effect of dispersal rate and spatiotemporal heterogeneity in predation by the selective planktiv...

Despite the wide use of grass carp as an effective control strategy for nuisance aquatic macrophytes, there has been a great deal of uncertainty in terms of its perceived risk to North American aquatic ecosystems. Recent observations of feral (and sometimes diploid) individuals in the Great Lakes (GL) Basin have spurred interest in re-evaluating th...

Background/Question/Methods The metacommunity concept has emerged as a powerful framework to describe and forecast effects of community connectivity on species richness across multiple spatial scales. Although metacommunity theory can predict patterns of diversity at hierarchical scales in freshwater ecosystems, its potential contribution to unde...

Desiccation following prolonged air exposure challenges survival of aquatic plants during droughts, water drawdowns, and overland dispersal. To improve predictions of plant response to air exposure, we observed the viability of vegetative fragments of ten aquatic plant species (fanwort, coontail, common elodea, Brazilian elodea, parrotfeather, vari...

Background/Question/Methods The perceived ecological impact of a species motivates policy and management. In the 1960’s, herbivorous grass carp (Ctenopharyngodon idella) was imported to the U.S. as a biocontrol tool for aquatic weeds prior to a thorough assessment of its potential risk to ecosystems. Shortly after its introduction, observations o...

Background/Question/Methods Identifying species traits associated with the different stages of biological invasion remains a central focus of community ecology and conservation biology. The application of trait-centered models to evaluating the risk of species establishment and impact in non-native environments, however, is rare. In this study, e...

1. Recent studies indicate that large-scale spatial processes can alter local community structuring mechanisms to determine local and regional assemblages of predators and their prey. In metacommunities, this may occur when the functional diversity represented in the regional predator species pool interacts with the rate of prey dispersal among loc...

Metacommunity theory suggests that relationships between diversity and ecosystem stability can be determined by the rate of species dispersal among local communities. The predicted relationships, however, may depend upon the relative strength of local environmental processes and disturbance. Here we evaluate the role of dispersal frequency and loca...

One of the greatest threats to the biotic integrity of native aquatic communities over contemporary time scales is the invasion and rapid geographic spread of exotic species. Whereas dispersal rates of exotic species are documented to affect invasion success, few studies acknowledge the role of dispersal in both exotic and native species in mediati...

The evolutionary viability of an endangered species depends upon gene flow among subpopulations and the degree of habitat patch connectivity. Contrasting population connectivity over ecological and evolutionary timescales may provide novel insight into what maintains genetic diversity within threatened species. We employed this integrative approach...

Trophic cascades, in which changes in predation affect the biomass of lower trophic levels, vary substantially in strength and incidence. Most work to explain this variation has focused on local factors and has ignored larger regional effects. To study how metacommunity dynamics can alter trophic cascades, we constructed mesocosm metacommunities co...