research

Greenhouse research at NDSU in Fargo.

Greenhouse research at NDSU in Fargo.

The central theme of my research is arthropod ecology. Arthropods, though immensely diverse and numerous, can be easily overlooked because of their small size. But it often turns out that their aggregate effects on ecosystems are large, and so I study arthropods (insects, spiders, mites, etc.) in a variety of “natural” and agricultural contexts to explore just how important these tiny critters are.

 

Ecosystem/Habitat Linkages


Many aquatic insects move to land when they become adults, including the ubiquitous midge family (Chironomidae). On land, these insects may be eaten with resulting impacts on the food web, or they might simply die and decay on land with consequences for nutrient availability. My dissertation explored these ideas at Lake Mývatn in northeast Iceland from 2008-2013.

Midge swarms at Lake Mývatn, May 2010

Midge swarms at Lake Mývatn, May 2010

Not all habitat boundaries are as stark as those that occur at a lake shoreline. Landscapes are a mosaic of habitat patches of varying quality, extent, and temporal duration. When and how far organisms, especially arthropods, move on the landscape can be crucial to understanding ecological patterns, including those in agroecosystems. I’ve explored some of these ideas in a paper written with Claudio Gratton, and I hope to pursue these ideas increasingly in the future.

  • Jamin Dreyer, David Hoekman, Claudio Gratton. 2015. Positive indirect effect of aquatic insects on terrestrial prey is not offset by increased predator density. Ecological Entomology. 
  • Dreyer, Jamin, Phil A. Townsend, James C. Hook III, M. Jake Vander Zanden, David Hoekman, Claudio Gratton. 2015. Quantifying aquatic insect deposition from lake to land. Ecology 96(2):499-509.
  • Hilary Bultman, David Hoekman, Jamin Dreyer, Claudio Gratton. 2014. Terrestrial deposition of aquatic insects increases plant quality for insect herbivores and herbivore density. Ecological Entomology 39(4):419-426.
  • Dreyer, Jamin and Claudio Gratton. 2014. Habitat linkages in conservation biological control: lessons from the land-water interface. Biological Control 75(2014) 68-76.
  • Dreyer, Jamin, David Hoekman ,Claudio Gratton. 2012. Lake-derived midges increase abundance of shoreline terrestrial arthropods. Oikos 121:2 252-258.
  • Hoekman, David, Jamin Dreyer, Randall D Jackson, Philip A Townsend, Claudio Gratton. 2011. Lake to land subsidies: experimentally simulating aquatic insect deposition. Ecology 92:2063-2072.

 

Predator/Prey Behavior


Claudio working the mesocosms

Mesocosm predator experiment.

Charismatic predators have wide appeal, even when they are small arthropods like spiders. And who cannot respect a prey species as it attempts to eat without being eaten? The behavior of both predators and prey combine to create patterns of consumptive and non-consumptive effects in food webs and on communities.

While at NDSU I worked on a small project investigating anti-predator behavior of soybean aphids, an invasive pest. At UK I’ve explored how temperature can influence the spatial distribution of predators and prey to impact crop damage.

  • Jamin Dreyer, David Hoekman, Claudio Gratton. 2015. Positive indirect effect of aquatic insects on terrestrial prey is not offset by increased predator density. Ecological Entomology.

 

Indirect Effects


Sampling at a field experiment site in Iceland.

Sampling at a field experiment site in Iceland.

The direct impacts of predation, nutrient availability, competition, temperature, etc. are (sometimes) obvious, but cascading or indirect effects of these changes may be less intuitively observed. A major dynamic at play along ecosystem boundaries is the indirect effect that mobile organisms, e.g. midge prey, have on the “resident” organisms through predator species that consume both groups.

In agroecosystems too, the indirect effects of predators and other natural enemies on crop production, also called a “trophic cascade”, is a critical component of sustainable agriculture.

  • Jamin Dreyer, David Hoekman, Claudio Gratton. 2015. Positive indirect effect of aquatic insects on terrestrial prey is not offset by increased predator density. Ecological Entomology.
  • Hilary Bultman, David Hoekman, Jamin Dreyer, Claudio Gratton. 2014. Terrestrial deposition of aquatic insects increases plant quality for insect herbivores and herbivore density. Ecological Entomology 39(4):419-426.

 

Agroecosystem Functioning


After moving from the heathlands of Iceland to the fields of the US Midwest, I’ve been directly involved in agricultural research. But even before that, as a member of Claudio Gratton’s Lab I was already steeped in the ideas and language of ecological research in agroecosystems.

Row cover trials in Kentucky.

Row cover trials in Kentucky.

There is growing talk about what, exactly, we are going to do to take care of 9+ billion people on the planet by the middle of this century. In my roles as both research scientist and science policy advocate, and as a global citizen, I can’t ignore the pressing importance of this issue and look to expand this area of research in the future.

 

  • Xia, Ye, Seth DeBolt, Jamin Dreyer, Delia Scott, and Mark A. Williams. 2015. Characterization of culturable bacterial endophytes and their capacity to promote plant growth from plants grown using organic or conventional practices. Frontiers in Plant Science 6:490.
  • Dreyer, Jamin and Claudio Gratton. 2014. Habitat linkages in conservation biological control: lessons from the land-water interface. Biological Control 75(2014) 68-76.