Scholarly Work - Ecology
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/8716
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Item Natural Ecosystems I. The Rocky Mountains(2003-10) Reiners, William A.; Baker, William L.; Baron, Jill S.; Debinski, Diane M.; Elias, Scott A.; Fagre, Daniel B.; Findley, James S.; Mearns, Linda O.; Roberts, David W.; Seastedt, Timothy R.; Stohlgren, Thomas J.; Veblen, Thomas T.; Wagner, Frederic H.This assessment of climate-change effects on Rocky Mountain terrestrial ecosystems is prepare from information generated by a workshop focused on terrestrial systems of the Rocky Mountains, and held in Boulder, CO, on 29-30 September 2000 at the National Center for Atmospheric Research. It is a compilation of this workshop's discussion along with material from earlier workshops.Item Forest Fragmentation and Matrix Effects: The Matrix Does Matter(2006-10) Debinski, Diane M.When ecologists envision a traditional habitat fragmentation study, they usually conjure up an image of very discrete fragments, perhaps rectangular or even square, surrounded by a matrix of very different, inhospitable habitat. Patch equals habitat; matrix equals wasteland. We are well aware that real-world landscapes do not fit into such perfectly geometric, discrete packages. However, black and white dichotomies are easier to model, and these models are easily envisioned when we ponder effects of fragmentation.Item Regal Fritillary and its Host Plant Studied at Neal Smith National Wildlife Refuge (Iowa)(2000-12) Debinski, Diane M.; Drobney, PaulineTraditional tallgrass prairie restoration efforts have focused primarily on planting and managing the dominant species of prairie vegetation. Meanwhile, little is known about techniques for restoring prairie insect species, many of which play important roles in pollination and seed dispersal. The regal fritillary (Speyeria idalia) is a prairie endemic butterfly that was once abundant in the Midwest, but now occurs in small, widely-separated populations. The regal and its host plants~bird’s-foot violet (Viola pedata) and prairie violet (V. pedatifida) in Iowa--are found almost exclusively in unplowed native prairie. We have initiated an experiment to restore the regal fritillary at the 5,000-acre Neal Smith National Wildlife Refuge (NWR), which is located just east of Des Moines. Here we report on previous research as well as our progress to date in restoring the regal fritillary.Item Butterflies and Continuous Conservation Reserve Program Filter Strips: Landscape Considerations(2006-11) Davros, Nicole M.; Debinski, Diane M.; Reeder, Kathleen F.; Hohman, William L.Filter strips or buffers are areas of grass or other perennial herbaceous vegetation established along waterways to remove contaminants and sediments from agricultural field runoff. In the heavily cultivated regions of the Midwestern United States, these buffer zones established under the Farm Bill provide important habitat for wildlife such as butterflies. The question of how the landscape context of these plantings influences their use has not been adequately researched. We used multiple regression and Akaike's Information Criteria to determine how habitat width and several landscape‐level factors (i.e., landscape composition [total herbaceous cover, amount of developed area, and amount of wooded cover] and configuration [herbaceous edge density]) influenced the abundance and diversity of the butterfly community using filter strips in southwestern Minnesota, USA. Habitat‐sensitive butterfly abundance and all richness and diversity measures were positively correlated with filter‐strip width. Butterfly abundance was negatively associated with the amount of developed areas (cities, towns, and roads) within the area of a 1‐km radius (3.14 km2) surrounding the sites. Percentage of wooded cover in the landscape was an important variable explaining individual species abundance, although the direction of the relationship varied. Our finding that landscape context influences butterfly use of filter strips highlights the importance of landscape‐level approaches to wildlife conservation in agroecosystems.Item Butterfly Responses to Prairie Restoration Through Fire and Grazing(2007-11) Vogel, Jennifer A.; Debinski, Diane M.; Koford, Rolf R.; Miller, James R.The development of land for modern agriculture has resulted in losses of native prairie habitat. The small, isolated patches of prairie habitat that remain are threatened by fire suppression, overgrazing, and invasion by non-native species. We evaluated the effects of three restoration practices (grazing only, burning only, and burning and grazing) on the vegetation characteristics and butterfly communities of remnant prairies. Total butterfly abundance was highest on prairies that were managed with burning and grazing and lowest on those that were only burned. Butterfly species richness did not differ among any of the restoration practices. Butterfly species diversity was highest on sites that were only burned. Responses of individual butterfly species to restoration practices were highly variable. In the best predictive regression model, total butterfly abundance was negatively associated with the percent cover of bare ground and positively associated with the percent cover of forbs. Canonical correspondence analysis revealed that sites with burned only and grazed only practices could be separated based on their butterfly community composition. Butterfly communities in each of the three restoration practices are equally species rich but different practices yield compositionally different butterfly communities. Because of this variation in butterfly species responses to different restoration practices, there is no single practice that will benefit all species or even all species within habitat-specialist or habitat-generalist habitat guilds.Item Butterflies Like Wide Buffer Strips with Tall Native Grasses and(2007-01) Debinski, Diane M.; Hohman, William L.If you want more species of butterflies in your filter strips and other grass buffers, make the buffers wider and plant tall native grasses and broad leaf plants. That’s a key finding of a southwestern Minnesota study on butterfly use of conservation buffers.Item Butterfly, bee and forb community composition and cross-taxon incongruence in tallgrass prairie fragments(2008-02) Davis, Jessica; Hendrix, Stephen D.; Debinski, Diane M.; Hemsley, ChiaraPollinators provide an important class of ecological services for crop plants and native species in many ecosystems, including the tallgrass prairie, and their conservation is essential to sustaining prairie remnants. In Iowa these remnants are typically either block-shaped or long, linear strips along transportation routes. In this study we examined differences in the butterfly, bee, and forb community composition in linear and block prairie remnants, determined correlations between species diversity among butterflies, bees and forbs in the 20 prairie remnants sampled, and examined correlations of community similarity among butterflies, bees and forbs. Correspondence analysis showed that distinct communities exist for butterflies and forbs in block versus linear sites and discriminant analysis showed that the bee and forb communities in block and linear sites can be distinguished on the basis of a few species. Diversity of one group was a poor predictor of diversity in another, except for a significant inverse relationship between bees and butterflies. These two pollinator taxa may be responding very differently to microhabitat components within fragmented ecosystems. Our studies show that there need to be differences in conservation strategies for bees and butterflies to maintain both pollinator communities.Item Changes in Vegetation Structure through Time in a Restored Tallgrass Prairie Ecosystem and Implications for Avian Diversity and Community Composition(2009-12) Olechnowski, Brian F.; Debinski, Diane M.; Drobney, Pauline; Viste-Sparkman, Karen; Reed, William T.Grassland birds are one of the most endangered taxa in temperate North America. Because many species declines have been linked to habitat fragmentation and loss, large-scale prairie restoration projects have the potential to provide critical habitat for these declining species. We examined how the structure of restored grassland habitat changes through time and how diversity and community composition of grassland birds respond to these changes. Our study was completed at Neal Smith National Wildlife Refuge, a large-scale prairie restoration in central Iowa. Vegetation composition and structure were measured at 42 restored grassland plots throughout the refuge in 2007. Birds were surveyed at these locations from 1994 to 2007. Survey points were sorted into five categories (out of crop rotation for 1, 2, 3, 4–6, and > 6 y). In the initial phases of restoration, species such as horned larks, red-winged blackbirds, and killdeer were abundant. Other species such as common yellowthroats and dickcissels were more common in established restored points. Henslow’s sparrows appeared only at survey points that were out of crop rotation for more than 6 years. Diversity peaked in survey points that were 2–3 years out of crop rotation and points that were more than 6 years out of rotation. Community composition shifted through the chronosequence of prairie plantings. Changes in diversity and shifts in community composition can be explained by changes in vegetative structure. Our results suggest that managing for a variety of restored prairie stages will best maintain the highest levels of avian diversity and abundance.Item Nest Success of Yellow Warblers in Willow Habitats: The Role of Surface Water and Snakes(2004-01) VanNimwegen, Ron E.; Debinski, Diane M.Yellow Warblers (Dendroica petechia) are migratory songbirds found in high abundance in the tall willow (Salix boothii) habitats of Grand Teton National Park (GTNP). Willows are found in wet soils with high water tables and varying densities of exposed surface water. Dense surface area of water leads to thick, well foliated, continuous patches of S. boothii, which is the favored nesting habitat of Yellow Warblers. This water, however, also supports the favored prey base of the wandering garter snake (Thamnophis elegans vagrans), which has been known to prey on songbird nest contents when the opportunity arises. We hypothesized that nest territories containing high densities of surface water would also attract garter snakes, and increase the probability of nest failures. We found and monitored 28 Yellow Warbler nests, recorded their locations and fates (success or failure) and measured the density of surface water within each nest territory. We analyzed nest success with the logistic-exposure method coupled with comparisons of models with and without water density as an explanatory variable. Information theoretic model comparison consistently supported models with water density over those without. A significant correlation was found between water density within a nest territory and that nest's daily survival probability. The estimate of this effect was -0.049 (a logistic model parameter) with a standard error of 0.019. Expressed alternatively, each 5-meter per territory increase in waterway density decreases the odds ratio of nest survival by 21%. While water density provides a trade off between nesting habitat and predation pressure, other predation causes and temporal water density variation likely contribute to overall warbler productivity in important ways as well.Item Quantifying Early Indicators of Global Climate Change(2006-01) Debinski, Diane M.One of the more significant voids remaining in our scientific understanding of global climate change is the relationship between climate change and the resulting changes expected in ecological communities. Because a large proportion of the North American landscape has been modified by human activities, it is difficult to assess whether ecological changes are being caused by human activities or climate change. Thus, we must look to landscapes where the modification has been less severe. One of the most pristine landscapes in North America where scientists can study natural processes is that of the Greater Yellowstone Ecosystem. Within this system some of the more sensitive habitats are the montane meadows. These habitats exist along a continuum from very dry (xeric) sagebrush meadows, to flowering (mesic) meadows, to wet (hydric) sedge meadows. Because of the relatively short growing season, species in these meadows can exhibit quick changes in distribution and abundance relative to climatic changes. My research uses satellite images and field surveys to evaluate how meadow habitats and their associated species respond to interannual changes in precipitation and soil moisture. I am examining the plant and butterfly communities to measure the response. Over 100 species of butterflies occur in this area and many are closely associated with specific types of meadows. This research is significant because it will provide an early warning system for assessing the effects of climate change. Documenting changes in montane meadows will assist in understanding how climate change may affect more highly managed areas of the globe.