Novel Predator-Prey Interactions in Aquatic Ecosystems

Despite many examples of non-native species that exert large predatory effects on native prey, we know very little about how invasions of non-native prey affect native predators. This gap in our understanding of species invasions reduces our ability to predict the strength of biotic resistance and enemy release experienced by non-native prey species. Current projects include:

1) Invasive Green Porcelain Crab (Petrolisthes armatus) as novel prey for native predators in oyster reef communities.

2) Predator-mediated apparent competition between the invasive rusty crayfish (Orconectes rusticus) and native Sanborn’s crayfish (Orconectes sanborni).

Sensory & Behavioral Responses to Human-Induced Rapid Environmental Change in African Cichlids

Although human-induced rapid environmental change (HIREC) often leads to biodiversity loss, some species are able to cope with multiple environmental stressors through phenotypic plasticity and/or genetic evolution. Phenotypic change in response to HIREC has been documented in a broad array of taxa; however, we understand very little about when phenotypic change is adaptive and promotes population persistence or is maladaptive and leads to population decline. In collaboration with Dr. Suzanne Gray and with funding through the National Science Foundation, we aim to link HIREC-driven phenotypic change with the adaptive value of trait changes, by determining (1) the functional significance of trait changes, and, (2) the mechanisms by which trait changes confer a fitness advantage. To do this, we will take advantage of known divergence in sensory and behavior traits associated with reproduction in populations of an African cichlid fish experiencing extremes of multiple environmental stressors.

Nutrient Enrichment & Harmful Algal Blooms in the Upper Ohio River Basin

I am excited to continue investigating how other drivers of global change (i.e. beyond invasive species) alter species interactions within aquatic ecosystems. To that end, I am a co-investigator with Drs. Mazeika Sullivan (PI) and Kai Zhao (Co-investigator) on two grants, one from the EPA-STAR program and the other from Ohio Corn and Small Grains Marketing Program to study the causes and consequences of nutrient enrichment in streams and reservoirs in the upper Ohio River Basin.

Biological Invasions, Biodiversity and Water Quality in Restored Coastal Wetlands

Historically, coastal wetlands along the Western Lake Erie Basin (WLEB) supported a wide range of ecosystem services, such as improving water quality, preventing shoreline erosion, retaining nutrients, and biodiversity support. Today, only 5% of Lake Erie’s coastal wetlands remain and the majority of these are diked, thereby severing the hydrological connections needed to sustain ecologically and economically important ecosystem functions. Although restoring wetland hydrology is expected to have long-term net benefits to WLEB and surrounding watershed, increased connectivity may increase invasions of non-native species, along with short-term increases in nutrients and sediments which may impact native fauna. Specific projects include:

  1. Evaluating changes in nutrient concentrations and macroinvertebrate taxonomic and functional trait diversity between reconnected & diked wetlands at the Ottawa National Wildlife Refuge.
  2. Evaluating whether differences in fish and macroinvertebrate taxonomic and functional trait diversity confer stronger resistance against biological invasion of non-native species in Lake Erie.

Impacts of Aquatic Invasive Macrophytes on Native Biota

Aquatic Invasive Macrophytes (AIMs) may have a particularly large impact on freshwater biodiversity through their impacts on both native aquatic plants and animals. With support from the Aquatic Ecosystems Restoration Foundation, we recently completed a meta-analysis quantifying the effects of AIMs on native macrophytes, macroinvertebrates and fish. Results indicated that there was a significant negative impact of AIMs on native macrophyte abundance, fitness, and diversity but no significant effect on growth.  AIMs had a significant positive effect on the survival of macroinvertebrates, but no effect on macroinvertebrate abundance or diversity. AIMs had a no effect on fish abundance relative to native macrophyte controls, but a negative effect on fish survival. Effects of AIMs on native biota also varied depending upon the growth form of the AIM, whether the study tested the effect of a single or multiple AIM and the study design.  From a management perspective, these results suggest that there could be trade-offs and mixed outcomes of AIM removal from invaded ecosystems.