Nathan R De Jager, PhD
I serve as a principal investigator and non-supervisory team leader for landscape ecological studies at the USGS Upper Midwest Environmental Sciences Center, where I have been since 2008. My research group uses a combination of field research and computer modelling to study how ecosystem processes respond to disturbances across large landscapes.
In the floodplain of the Upper Mississippi River, we study how spatial and temporal variation in flooding impacts plant and soil processes. Results from field studies are used to parameterize a spatially explicit simulation model that can be used to better understand and forecast effects of altered hydrological regimes and other disturbances (e.g., emerald ash borer, herbivory by white-tailed deer) on forest succession and nutrient cycling.
At Isle Royale National Park, we study how spatial and temporal variability in browsing by moose impacts plant and soil processes. Results from field studies are used to parameterize a spatially explicit simulation model that can be used to better understand and forecast effects of different moose population dynamics on forest succession in the context of climate change and predation by wolves.
In addition to these two primary study areas, I provide leadership and support for graduate students and other researchers working on a diverse array of topics, most of which require the use of GIS or other modelling approaches to link fine-scale measurements with landscape-scale phenomena. I frequently serve on regional to national scale working groups led by the USGS or other conservation groups and am an associate editor with the Natural Areas Journal.
Education and Certifications
2008 PhD in Ecology, Evolution, and Behavior with a minor in Conservation Biology, University of Minnesota, St. Paul, Minnesota
2005 MSc in Biology
Science and Products
Filter Total Items: 37
Spatial patterns of native freshwater mussels in the Upper Mississippi River
Multiple physical and biological factors structure freshwater mussel communities in large rivers, and their distributions have been described as clumped or patchy. However, few surveys of mussel populations have been conducted over areas large enough and at resolutions fine enough to quantify spatial patterns in their distribution. We used global and local indicators of spatial autocorrelation (i.
Authors
Patricia R. Ries, Nathan R. De Jager, Steven J. Zigler, Teresa Newton
An index of floodplain surface complexity
Floodplain surface topography is an important component of floodplain ecosystems. It is the primary physical template upon which ecosystem processes are acted out, and complexity in this template can contribute to the high biodiversity and productivity of floodplain ecosystems. There has been a limited appreciation of floodplain surface complexity because of the traditional focus on temporal varia
Authors
Murray W. Scown, Martin C. Thoms, Nathan R. De Jager
Effects of flooding on ion exchange rates in an Upper Mississippi River floodplain forest impacted by herbivory, invasion, and restoration
We examined effects of flooding on supply rates of 14 nutrients in floodplain areas invaded by Phalaris arundinacea (reed canarygrass), areas restored to young successional forests (browsed by white-tailed deer and unbrowsed), and remnant mature forests in the Upper Mississippi River floodplain. Plant Root Simulator ion-exchange probes were deployed for four separate 28-day periods. The first depl
Authors
Rebecca Kreiling, Nathan R. De Jager, Whitney Swanson, Eric A. Strauss, Meredith Thomsen
The Upper Mississippi River floodscape: spatial patterns of flood inundation and associated plant community distributions
Questions How is the distribution of different plant communities associated with patterns of flood inundation across a large floodplain landscape? Location Thirty-eight thousand nine hundred and seventy hectare of floodplain, spanning 320 km of the Upper Mississippi River (UMR). Methods High-resolution elevation data (Lidar) and 30 yr of daily river stage data were integrated to produce a ‘floodsc
Authors
Nathan R. De Jager, Jason J. Rohweder, Yao Yin, Erin E. Hoy
Measuring floodplain spatial patterns using continuous surface metrics at multiple scales
Interactions between fluvial processes and floodplain ecosystems occur upon a floodplain surface that is often physically complex. Spatial patterns in floodplain topography have only recently been quantified over multiple scales, and discrepancies exist in how floodplain surfaces are perceived to be spatially organised. We measured spatial patterns in floodplain topography for pool 9 of the Upper
Authors
Murray W. Scown, Martin C. Thoms, Nathan R. De Jager
Floodplain complexity and surface metrics: influences of scale and geomorphology
Many studies of fluvial geomorphology and landscape ecology examine a single river or landscape, thus lack generality, making it difficult to develop a general understanding of the linkages between landscape patterns and larger-scale driving variables. We examined the spatial complexity of eight floodplain surfaces in widely different geographic settings and determined how patterns measured at dif
Authors
Murray W. Scown, Martin C. Thoms, Nathan R. De Jager
Winter browse selection by white-tailed deer and implications for bottomland forest restoration in the Upper Mississippi River Valley, USA
White-tailed deer (Odocoileus virginianus) forage selectively, modifying upland forest species composition and in some cases shifting ecosystems to alternative stable states. Few studies, however, have investigated plant selection by deer in bottomland forests. Herbaceous invasive species are common in wetlands and their expansion could be promoted if deer avoid them and preferentially feed on nat
Authors
Benjamin J. Cogger, Nathan R. De Jager, Meredith Thomsen, Carrie Reinhardt Adams
Anticipated effects of development on habitat fragmentation and movement of mammals into and out of the Schoodic District, Acadia National Park, Maine
Most national parks interact with adjacent lands because their boundaries fail to encompass all regional habitats, species pools, and migration routes. Activities planned for adjacent lands can have adverse effects on park resources and visitor experiences. For example, fragmentation of adjacent habitat into smaller and more isolated remnants may influence the suitability of park habitat for a wid
Authors
Jason J. Rohweder, Nathan R. De Jager, Glenn R. Guntenspergen
Threshold effects of flood duration on the vegetation and soils of the Upper Mississippi River floodplain, USA
Most large rivers have experienced major changes in hydrology and land use over the past century, with concomitant effects on sedimentation, nutrient cycling and biodiversity. To restore and/or enhance these ecosystems, managers need to know where their efforts are most likely to succeed under current hydrologic regimes as well as under potential future hydrologic regimes. We therefore examined ch
Authors
Nathan R. De Jager, Meredith Thomsen, Yao Yin
Exploring relationships among land ownership, agricultural land use, and native fish species richness in the Upper Mississippi River Basin
The general effects of agriculture on in-stream fish communities in the Upper Midwestern United States have been well studied for nearly three decades (Karr et al. 1985; Nerbonne and Vondracek 1991; Zimmerman et al. 2001; Goldstein and Meador 2005). Specific impacts include: lowered water levels, sediment loading and nutrient enrichment, loss of riparian habitat, changes to channel morphometry and
Authors
Nathan R. De Jager, Jason J. Rohweder
Temporal changes in spatial patterns of submersed macrophytes in two impounded reaches of the Upper Mississippi River, USA, 1998-2009
We examined temporal changes in spatial patterns of submersed aquatic macrophytes during a recent three-fold increase in macrophyte abundance and in response to the cumulative effects of management actions (island construction and water level management) and changes in regional environmental conditions (turbidity) in two navigation pools of the Upper Mississippi River, Pool 8 (managed) and Pool 13
Authors
Nathan R. De Jager, Yao Yin
Spatial scaling of core and dominant forest cover in the Upper Mississippi and Illinois River floodplains, USA
Different organisms respond to spatial structure in different terms and across different spatial scales. As a consequence, efforts to reverse habitat loss and fragmentation through strategic habitat restoration ought to account for the different habitat density and scale requirements of various taxonomic groups. Here, we estimated the local density of floodplain forest surrounding each of ~20 mill
Authors
Nathan R. De Jager, Jason J. Rohweder
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Filter Total Items: 37
Spatial patterns of native freshwater mussels in the Upper Mississippi River
Multiple physical and biological factors structure freshwater mussel communities in large rivers, and their distributions have been described as clumped or patchy. However, few surveys of mussel populations have been conducted over areas large enough and at resolutions fine enough to quantify spatial patterns in their distribution. We used global and local indicators of spatial autocorrelation (i.AuthorsPatricia R. Ries, Nathan R. De Jager, Steven J. Zigler, Teresa NewtonAn index of floodplain surface complexity
Floodplain surface topography is an important component of floodplain ecosystems. It is the primary physical template upon which ecosystem processes are acted out, and complexity in this template can contribute to the high biodiversity and productivity of floodplain ecosystems. There has been a limited appreciation of floodplain surface complexity because of the traditional focus on temporal variaAuthorsMurray W. Scown, Martin C. Thoms, Nathan R. De JagerEffects of flooding on ion exchange rates in an Upper Mississippi River floodplain forest impacted by herbivory, invasion, and restoration
We examined effects of flooding on supply rates of 14 nutrients in floodplain areas invaded by Phalaris arundinacea (reed canarygrass), areas restored to young successional forests (browsed by white-tailed deer and unbrowsed), and remnant mature forests in the Upper Mississippi River floodplain. Plant Root Simulator ion-exchange probes were deployed for four separate 28-day periods. The first deplAuthorsRebecca Kreiling, Nathan R. De Jager, Whitney Swanson, Eric A. Strauss, Meredith ThomsenThe Upper Mississippi River floodscape: spatial patterns of flood inundation and associated plant community distributions
Questions How is the distribution of different plant communities associated with patterns of flood inundation across a large floodplain landscape? Location Thirty-eight thousand nine hundred and seventy hectare of floodplain, spanning 320 km of the Upper Mississippi River (UMR). Methods High-resolution elevation data (Lidar) and 30 yr of daily river stage data were integrated to produce a ‘floodscAuthorsNathan R. De Jager, Jason J. Rohweder, Yao Yin, Erin E. HoyMeasuring floodplain spatial patterns using continuous surface metrics at multiple scales
Interactions between fluvial processes and floodplain ecosystems occur upon a floodplain surface that is often physically complex. Spatial patterns in floodplain topography have only recently been quantified over multiple scales, and discrepancies exist in how floodplain surfaces are perceived to be spatially organised. We measured spatial patterns in floodplain topography for pool 9 of the UpperAuthorsMurray W. Scown, Martin C. Thoms, Nathan R. De JagerFloodplain complexity and surface metrics: influences of scale and geomorphology
Many studies of fluvial geomorphology and landscape ecology examine a single river or landscape, thus lack generality, making it difficult to develop a general understanding of the linkages between landscape patterns and larger-scale driving variables. We examined the spatial complexity of eight floodplain surfaces in widely different geographic settings and determined how patterns measured at difAuthorsMurray W. Scown, Martin C. Thoms, Nathan R. De JagerWinter browse selection by white-tailed deer and implications for bottomland forest restoration in the Upper Mississippi River Valley, USA
White-tailed deer (Odocoileus virginianus) forage selectively, modifying upland forest species composition and in some cases shifting ecosystems to alternative stable states. Few studies, however, have investigated plant selection by deer in bottomland forests. Herbaceous invasive species are common in wetlands and their expansion could be promoted if deer avoid them and preferentially feed on natAuthorsBenjamin J. Cogger, Nathan R. De Jager, Meredith Thomsen, Carrie Reinhardt AdamsAnticipated effects of development on habitat fragmentation and movement of mammals into and out of the Schoodic District, Acadia National Park, Maine
Most national parks interact with adjacent lands because their boundaries fail to encompass all regional habitats, species pools, and migration routes. Activities planned for adjacent lands can have adverse effects on park resources and visitor experiences. For example, fragmentation of adjacent habitat into smaller and more isolated remnants may influence the suitability of park habitat for a widAuthorsJason J. Rohweder, Nathan R. De Jager, Glenn R. GuntenspergenThreshold effects of flood duration on the vegetation and soils of the Upper Mississippi River floodplain, USA
Most large rivers have experienced major changes in hydrology and land use over the past century, with concomitant effects on sedimentation, nutrient cycling and biodiversity. To restore and/or enhance these ecosystems, managers need to know where their efforts are most likely to succeed under current hydrologic regimes as well as under potential future hydrologic regimes. We therefore examined chAuthorsNathan R. De Jager, Meredith Thomsen, Yao YinExploring relationships among land ownership, agricultural land use, and native fish species richness in the Upper Mississippi River Basin
The general effects of agriculture on in-stream fish communities in the Upper Midwestern United States have been well studied for nearly three decades (Karr et al. 1985; Nerbonne and Vondracek 1991; Zimmerman et al. 2001; Goldstein and Meador 2005). Specific impacts include: lowered water levels, sediment loading and nutrient enrichment, loss of riparian habitat, changes to channel morphometry andAuthorsNathan R. De Jager, Jason J. RohwederTemporal changes in spatial patterns of submersed macrophytes in two impounded reaches of the Upper Mississippi River, USA, 1998-2009
We examined temporal changes in spatial patterns of submersed aquatic macrophytes during a recent three-fold increase in macrophyte abundance and in response to the cumulative effects of management actions (island construction and water level management) and changes in regional environmental conditions (turbidity) in two navigation pools of the Upper Mississippi River, Pool 8 (managed) and Pool 13AuthorsNathan R. De Jager, Yao YinSpatial scaling of core and dominant forest cover in the Upper Mississippi and Illinois River floodplains, USA
Different organisms respond to spatial structure in different terms and across different spatial scales. As a consequence, efforts to reverse habitat loss and fragmentation through strategic habitat restoration ought to account for the different habitat density and scale requirements of various taxonomic groups. Here, we estimated the local density of floodplain forest surrounding each of ~20 millAuthorsNathan R. De Jager, Jason J. Rohweder