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The driving question behind my research program is the role of space in ecological systems. I have a number of projects addressing specific components of this broad question, which I describe below. You can either scroll down or use the links to jump to a specific project. Animal movement behavior in heterogeneous landscapes Landscape ecology of prairie patches in eastern ND-western MN Host-parasite dynamics on dynamic landscapes Survival, movements, and habitat use of eastern wild turkeys translocated to Northwestern Minnesota Review of on-site wetland mitigation effectiveness in North Dakota If you are interested in any more information about my research program, collaborating, or joining my lab as a student or postdoc then please contact me: brett.goodwin@und.nodak.edu. |
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Description: Gypsy moths (Lymantria dispar) are an introduced forest pest in the US northeast. At our study site at the Institute of Ecosystem Studies in Millbrook, NY, moth pupae are heavily preyed upon by white-footed mice (Peromyscus leucopus). Mice are usually abundant, broad generalists, seem to display a type II functional response to moth pupae, and prey heavily on moth pupae. All these factors suggest that mice should be capable of extirpating moths. Yet, at our study site moths have persisted for over two decades and they have successfully established and spread throughout the US northeast since their introduction. How are moth populations persisting? The natural history of this predator-prey system provide two interesting clues as to how moths might persist. First, female adult gypsy moths are flightless and lay their eggs near where they eclose from the pupal stage. At least for females, all dispersal is achieved during the larval stage with young, small caterpillars floating in the wind using silk strands they expel and older, larger caterpillars walking between trees. Such means of dispersal suggest that most offspring won't get far and dispersal will be relatively limited. Such limited dispersal should concentrate offspring in relatively small areas and possible allow some offspring to avoid predation. Secondly, white-footed mice forage in a spatially heterogeneous manner. Mice are territorial, tend to avoid some habitats due to predation risk, and may cue in on other, abundant food sources - all of which tend to produce areas of high risk of predation by mice and areas of low risk of predation by mice. These low risk areas could allow a few moth offspring to survive through the pupal stage. Could either of these factors, or the combination of the two promote moth persistence? As part of my post-doc work at the Institute of Ecosystem Studies, I developed a spatially-explicit, individual based model of moth population dynamics undergoing spatially heterogeneous mouse predation to answer that question. Preliminary modeling results suggested that neither limited moth dispersal nor spatially heterogeneous predation alone could produce moth persistence but the combination of the two could. My colleagues and I are still exploring the dynamics of this individual-based model and trying to develop a tractable, analytical model of this system. |
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Surfaces representing risk of predation by mice in the model. The higher
the surface the greater the risk of predation at that particular spot.|
The modeling results depended on the details of moth dispersal and the spatial pattern of risk due to mouse predation. Both parameters are unknown so we conducted experiments to measure life-time moth dispersal and the pattern of mouse space-use and predation upon moth pupae. Moth dispersal was measured by placing burlap bands on trees surrounding isolated egg masses to see where larvae hatching from those egg masses end up just before pupation. We assessed the spatial pattern of mouse foraging using tracking plates and by placing gypsy moth pupae embedded in bees wax (to both restrain the pupae and record tooth marks of any predators that take pupae) in the field. Additionally, we tested predictions from the model by manipulating mouse space use (through supplemental feeders) and tracking the impact of changing the spatial pattern of risk on gypsy moth survival. |
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A late instar
gypsy moth caterpillar found under a burlap band. The green marks are
paint used to avoid double counting caterpillars.
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Collaborators:
Dr.
Clive Jones - Institute of Ecosystem Studies
Project
alumni: Renee Baker - Project Assistant 2004 Funding: National Science Foundation |
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Description: My PhD work looked at movement behavior of a goldenrod specialist beetle, Trirhabda borealis, in different vegetation patches - patches of goldenrod, patches of cut vegetation and patches of cut vegetation with artificial plant structure via suspended camouflage netting - and at the edges between those patches. Those movement behaviors were incorporated into an individual-based, spatially explicit simulation model of beetle movements. We used this model to assess how altering landscape structure could influence the ability of the beetles to move between habitat patches (otherwise known as landscape connectivity). Finally, model predictions were tested using capture-mark-release-resight experiments. |
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An
experimental landscape with goldenrod patches and cut patches.|
I intend to expand on this work using insects moving through heterogeneous prairie vegetation. There are two goals to this work. First, to extend the study of movement behavior in response to landscape elements to more insect species. Second, to investigate possible modifiers of the behavioral response to landscape structure (e.g., nutritive or reproductive state of the moving individual). I have gathered preliminary data at Oakville prairie (a UND field lab) to determine potential insect and associated plant species to be investigated. This past summer, a undergraduate student, Rob McCann, worked on a project looking at katydid movement behavior. I have submitted an NSF grant to seek funding for this work. Collaborators: Dr. Lenore Fahrig - Carleton University (PhD supervisor)
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NSERC (graduate scholarship) |
Landscape ecology of prairie patches in eastern ND-western MN |
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Description: Habitat loss and fragmentation due to human induced land use change, such as converting natural areas to agriculture, critically impacts native plants and animals. In fact, loss of habitat and the fragmentation of that habitat into small, isolated patches is one of the leading drivers of the current extinction crisis. Tall-grass and mixed-grass prairies have been heavily altered by human activities. In Minnesota alone, over 99% of native prairie has been lost since European settlement. Yet much of the research on the impact of habitat loss and fragmentation has been conducted in forested habitat. Very little is known about how prairie species respond to habitat loss and fragmentation. Also, habitat patches do not exist in a theoretical vacuum but are embedded in real landscapes. The nature of the land around a habitat patch (e.g., types of patches and their pattern) may impact the plants and animals of that patch. For example, a small prairie patch surrounded by fallow land may be as suitable for prairie species as a larger prairie patch surrounded by intensely farmed fields. This effect of the surrounding landscape on habitat patch quality has received less attention than the impact of habitat fragmentation. Most studies of prairie fragmentation to date have focused on larger animals such as mammals, birds, reptiles and amphibians. We know very little about how insects respond to prairie fragmentation. Yet, insects are an important component of prairie ecosystems either as food for other animals or pollinators for prairie plants. Additionally, a number of insects are either threatened or endangered (e.g., the Dakota Skipper butterfly). Twenty prairie patches and the surrounding landscape have been characterized from aerial photographs and satellite imagery using GIS. For each prairie patch we have measured patch size, shape and isolation from other prairie patches. Also, for each prairie patch the composition of the surrounding landscape (in terms of different land use types) has been determined at various spatial scales (different distances away from the prairie patch). The insect community on each prairie patch was sampled using sweep net samples, pit fall traps, and Malaise (flight intercept) traps. We are relating the patch and landscape characters to measures of community structure using statistical model selection approaches. Collaborators: Ms. Sarah Fischer - University of North Dakota, MS student, graduated Spring 2006 Funding: Faculty Research Seed Money Award, UND |
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Description: A group of researchers at UND (including biologists, geographers and geologists) are working together to understand the dynamics of host-parasite or host-pathogen interactions on spatially-explicit, dynamic landscapes. I am contributing to this effort by developing a spatially-explicit simulation model of host-parasite or host-pathogen dynamics. This model will be parameterized and tested against a number of field systems.
Collaborators: Funding: ND-EPSCoR |
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Survival, movements, and habitat use of eastern wild turkeys translocated to Northwestern Minnesota |
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Description: The state of Minnesota is seeking to establish wild turkey populations in the northern regions of the state. However, little is currently known about how turkey will survive in northwestern Minnesota. Furthermore, winter weather may drive turkey to use farm fields and stored hay for foraging which could lead to conflicts with farmers. We are studying survivorship, movements and habitat use of released turkey using radio-tracking.
Collaborators:
Mr. Chad Parent - UND, MS student Funding: Minnesota DNR |
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Review of on-site wetland mitigation effectiveness in North Dakota |
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Description: Due to the large number of wetlands in North Dakota, road construction often impacts wetlands and results in the construction of mitigation wetlands. The US Fish and Wildlife service is interested in comparing both on-site and off-site mitigation wetlands to non-impacted wetlands. Surprisingly little work has been done to look at constructed mitigation wetlands to see if they are indeed functioning like the wetlands they are intended to replace. This study is meant to help address that need.
Collaborators:
Ms. Fawn Wasin Zi - UND, MS student Funding: Minnesota DNR |
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