Updated Text for Lab Web Page

Updates for Turner lab web site

MGT April 21, 2006

MGT added May 2, 2006

Research

Fire, vegetation and ecosystem processes in Yellowstone National Park

The size and severity of the fires that burned through Yellowstone National Park (YNP) and surrounding lands (MAP) during the summer of 1988 surprised scientists, park managers and the general public. The 1988 fires were a large, infrequent but natural disturbance that created a complex landscape mosaic. Since the fires, Turner and colleagues, especially Dr. William H. Romme (Colorado State University) and Dr. Daniel B. Tinker (University of Wyoming) have been studying the effects of fire size and pattern on postfire vegetation and ecosystem processes. Natural disturbances are key sources of heterogeneity in many ecosystems, yet the causes and consequences of disturbances that are large, severe and infrequent are not well understood.

Read more about our research results… <this goes to the page you already have>

Current projects…<see below for where this will go…>

Current projects

Our current research in the Yellowstone region includes three major efforts.

How do disturbance-generate landscape patterns influence the spatial dynamics of ecosystem processes? With funding from the Andrew W. Mellon Foundation, we are focusing on the interactions between vegetation and ecosystem processes, with particular emphasis on nitrogen cycling and the role of post-fire coarse wood, following stand-replacing fire. This study has continued a main focus on areas burned by the 1988 fires, but we have also initiated studies in areas burned during 2000 and 2003 as well as along a chronosequence of stand ages. In addition, we studied within-stand spatial heterogeneity in soil processes and microbial communities in a boreal forest that burned in 2001. We have completed much of the field data collection associated with this work, and a number of analyses and papers are currently in preparation.

Currently, Liz Levitt (MS student) is examining whether the differences in stand structure and aboveground net primary production observed in young post-fire lodgepole pine stands are associated with difference in inorganic nitrogen availability across the Yellowstone landscape. This study will contribute to understanding ecosystem processes in heterogeneous landscapes and will be the first analysis to quantify variation in N availability among the post-1988 stands. Read more….

Carbon cycling at the lanscape scale: the effect of changes in climate and fire frequency on age distribution, stand structure and net ecosystem production (NEP). With funding from the Joint Fire Sciences Program, we are examining carbon balance across the entire Yellowstone landscape, how it might change under future climates and fire regimes, and how cycles of carbon and nitrogen interact. Climate, fire (frequency and intensity), and forest structure and development are strongly linked, but our knowledge of the interactions of these factors is poor. We lack the ability to make robust predictions about how changes in climate will alter these interactions and change the carbon balance of a landscape. Our objective is to estimate how changes in fire frequency, pattern, and intensity will alter the distribution of forest age and structure across a landscape and how these changes, in turn, will change the landscape carbon balance. We are determining the current carbon balance for the Yellowstone National Park (YNP) landscape and how much carbon was lost in the 1988 fires. We are also determining how NEP will change for the YNP landscape with changes in climate and fire regimes by calibrating the Century biogeochemical model to assess how changes in climate will alter NEP across stand development, and using models developed in past research to simulate fire frequency, fire spread, and the resulting landscape structure (the distribution of stand age and tree density) for alternative climatic condition. We hypothesize that variation in tree establishment after a fire and the legacy of the prior stand will control the trajectory of NEP through time, and that climate and fire frequency will change the distribution of forest age and structure, and these changes will alter net carbon storage for the landscape.

Currently, Erica Smithwick (postdoctoral research associate) is parameterizing the Century ecosystem model to simulate patterns of carbon and nitrogen stocks and fluxes along a chronosequence of stands in Yellowstone. We are particularly interest in simulating the variability in initial post-fire pine seedling density to explore how structural heterogeneity affects patterns of productivity and nutrient storage. Our collaborators include Drs. Michael Ryan (USFS), Dan Kashian, Bill Romme and Dan Tinker. Read more…

Reciprocal interactions between bark be4etles and wildfire in subalpine forests: landscape patterns and the risk of high-severity fire. Third, we are beginning (in 2006) studies of disturbance interactions in the Greater Yellowstone Area, focusing on fire and insect outbreaks. <continue with the text from Martin; we will not post our proposal until it is actually funded, however.>

HOT LINKS:

Mellon proposal

Carbon proposal <needs budgets etc. removed, I want science text and refs only>

Land-water interactions in north temperate landscapes

The interfaces between aquatic and terrestrial ecosystems (i.e., riparian zones) are key functional linkages in most temperate landscapes. Research in our lab has addressed a variety of land-water linkages, including large river-floodplain systems along the Wisconsin River; the Northern Highlands Lake District centered on Vilas County, Wisconsin; and lakes of the Madison area. We collaborate closely in these studies with researchers at the UW-Madison Center for Limnology, with our contribution typically focused on landscape patterns and processes (e.g., land-use change) or the drier side of the land-water interaction (e.g., riparian forests). Research falls under the auspices of the North Temperate Lakes Long-term Ecological Research (LTER) site; a Biocomplexity grant focusing on interactions among people and lakes; a spatially explicit regional modeling study of hydrologic and biogeochemical fluxes in a land-water mosaic; a study of critical thresholds related to eutrophication; and understanding the roles of flood regime and land-use change along the Wisconsin River.

Current projects

Divergent dynamics: complex interactions of riparian land, people and lakes. <can leave existing text here, including the project web page, then continue with Anna’s paragraph below.>

Currently, Anna Marburg (PhD student) has investigated the effects of lakeshore development on riparian forest and littoral coarse woody habitat. The main focus of her studies have been to understand the importance of cross-boundary subsidies in understanding the impact of residential development on ecosystems.

Alysa Remsburg (PhD student) has been building on the foundation of the biocomplexity and NTL-LTER research to address the influence of habitat heterogeneity (especially vertical vegetation structure) on dragonflies and damselflies (order Odonata), which are voracious generalist predators <continue with the text you had from Alysa>

LINKS TO DOCUMENTS INCLUDE:

Water Mellon proposal.doc <short proposal can be linked here>

EPA Science only.pdf <full proposal, science only>

LINKS TO OTHER WEB SITES:

NTL LTER <as we have them>

Biocomplexity <as we have them>

WIRF <is that link still live?>

Pick up here

Landscape ecology of ungulate populations

Understanding the influence of spatial heterogeneity on individual movements and population distributions has been a goal of ecological research for some time. We have been part of a 6-yr study (ending in summer 2006) focused on understanding how spatial heterogeneity shapes the habitat use and movement patterns of elk (Cervus elaphus) at multiple scales and in different landscapes. This project has involved four other principle investigators (Peter Turchin, University of Connecticut; John Fryxell, University of Guelph; Mark Boyce, University of Alberta; and Evie Merrill, University of Alberta) and graduate students and postdoctoral researchers at all sites. Four study landscapes were included, two in the Rocky Mountains (Yellowstone National Park, Wyoming, and Alberta) and two in eastern deciduous forest (Wisconsin and Ontario). Traditional VHF and newly developed global positioning system (GPS) biotelemetry were used at all four sites to monitor elk movements and habitat use. Spatial and temporal patterns of forage quantity and quality were determined for all landscapes, as were estimates of predation risk, and empirical data collection was integrated with spatial analyses and modeling. Read more …

Read more on the elk study – summary of our key findings:

Our proposal (click here to view proposal) focused on understanding how spatial heterogeneity shapes elk (Cervus elaphus) movement, population distribution and dynamics at multiple scales in complex landscapes. We conducted field research at four geographically distinct sites in Alberta, Ontario, Wisconsin, and Yellowstone National Park using traditional VHF and newly developed global positioning system (GPS) biotelemetry. Studying elk in diverse landscapes using the same approach allowed us to test the generality of observations at any one site and to understand the range of movement and habitat-use patterns exhibited by a generalist ungulate.

Unraveling the role of spatial heterogeneity in shaping elk movement, distribution, and abundance required the development and refinement of methods for analyzing spatial data; the quantitative challenges are non-trivial, and we made substantial contributions in this area. Methods were developed for correcting bias in GPS radiocollar data for habitat studies (Frair et al. 2004) and understanding the influence of GPS errors on movement-model parameterization (Jerde and Visscher 2005). We have worked extensively with resource selection functions (RSFs), which are statistical models of the relative probability of use of a spatial resource unit. RSFs are estimated by comparing environmental covariates at resource units used by animals to those available, e.g., a set of random landscape locations. We developed new statistical methods for estimating RSF models (Boyce 2004, Pearce and Boyce 2005, Johnson et al. 2005) and evaluating their predictive reliability (Boyce et al. 2002, Forester 2005). A new statistical method, the step-selection function (SSF), was developed for modeling movement relative to landscape characteristics (Fortin et al. 2005b). We have also used K-means to link movement behaviors to landscapes (Jerde et al. 2005) and linear state-space models with a Kalman filter to dissect patterns of elk movement (Forester et al. 2005). Simulation, correlated random walk, neural net, and Markov chain Monte Carlo (McMC) methods were used effectively in the statistical analyses of elk movement patterns (Morales 2004, Morales et al. 2004, Morales et al. 2005a) and for developing predictive models of movement modes based on habitat features (Frair et al. 2005b). In addition to these quantitative approaches, we also developed new methods for the estimation of elk forage biomass (Visscher et al. 2004) and the availability of forage buried by snow (Visscher et al. 2005b).

Our research revealed scale dependence related to landscape variation in patterns of elk movement and habitat use. Movement is the “glue” that cements spatial systems, and thus analysis of movement patterns has been one of our major foci. Elk moved longer distances (Fig. 1), and home ranges were larger in the coarse-grained landscapes (Alberta, Yellowstone) than in the fine-grained landscapes (Ontario, Wisconsin) (Anderson et al. 2005b, c; Morales et al. 2005b). Elk moved frequently within their home ranges, with preferred areas receiving high use because of multiple visits rather than long residence periods (Visscher et al. 2005a, Wolf et al. 2005, Anderson et al. 2005b). In Ontario, bi-phasic movements were common, with short movements clustered in foraging areas and long movements between foraging areas (Jenkins 2004, Morales 2004, Yott 2004, Hazell and Fryxell 2005). In Alberta, movements by translocated elk were greater than those made by resident elk (Frair et al. 2005a). Winter foraging decisions by elk reflected fine-scale habitat structure related to snow depth, slope, and forage biomass (Fortin et al. 2005a). Resource selection patterns were scale dependent, with landscape covariates differing among scales (e.g., Boyce et al. 2003, Anderson et al. 2005d). In Yellowstone, habitat selection varied between seasons (Boyce et al. 2003, Mao et al. 2005) and among individuals (Forester 2005, Forester et al. 2005).

Although not a goal in our proposal, we quickly learned that wolf (Canis lupus) predation has a major influence on elk movements, habitat use, and survival (e.g., Mao 2003, Mao et al. 2005, Anderson et al. 2005b, Frair et al. 2005a). At broad scales, elk home range locations are shaped by the presence of wolves (Anderson et al. 2005b). Perceived predation risk also influences vigilance (Fortin et al. 2004a, b), the direction and step length of movements (Anderson et al. 2005c, Fortin et al. 2005b), and suggests important trophic cascades (Anderson et al. 2005a, Fortin et al. 2005b). Our observations have suggested a variety of plausible predator-prey strategies that may be mediated by landscape heterogeneity; the four study landscapes provide variation in habitat amount and configuration, topography, and alternative prey that is ideal for studying these interactions.

This research has generated 34 publications to date, with ~30 additional papers in preparation. Six graduate student theses were completed and six more are in preparation, and we have trained six postdoctoral research associates. These scientists have all gained experience in state-of-the-art analyses of animal habitat use and movements, the integration of modeling and empirical study, and the art of collaborative research. More than 35 undergraduates have participated in our field studies. We organized symposia at the World Congress of the International Association for Landscape Ecology held in Darwin, Australia in 2003, which resulted in a special issue of Landscape Ecology (Anderson 2005), and at the joint meeting of INTECOL and ESA in Montreal, Canada, scheduled for August 2005. We have been involved in numerous public outreach efforts, including > 45 presentations to local conservation groups (e.g., Red Deer River Naturalists, Alberta Conservation Association), resource boards (e.g., Sunpine Forest Industry, Weyerhaueser, Rocky Mountain Elk Foundation), and school or community groups (e.g., Rocky Mountain Middle School, Ta Otha School, Rotary). Our work has received attention from local media at all sites. The Alberta research was featured in Rocky Mountain Elk Foundation’s Bugle in 2003, and the Wisconsin studies were included in Wisconsin Public Television’s In Wisconsin in 2004.

Landscape dynamics and ecological change in the Southern Appalachians

As part of the Coweeta Long-term Ecological Research (LTER) site since 1994, we have studied landscape and ecological changes in the mountains of western North Carolina working in close collaboration with Dr. Scott Pearson (Mars Hill College). We have focused especially on understanding the influence of land-use history, contemporary landscape patterns and the abiotic template on forest herbs and soils in the Southern Appalachian Region. There is a spatial gradient of land-use intensity within the region, with wide, flat river valleys receiving more intense use than the steep slopes. There are also temporal dynamics associated with the exurban development that currently characterizes the region, and forest cover has increased over the past 75 years as both population and housing density have also both increased. Read more about our research findings and current directions….