Digital Commons Network^™

Spatial Heterogeneity, Not Visitation Bias, Dominates Variation In Herbivory: Comment & Reply, James F. Cahill, Brenda B. Casper, David S. Hik, Svata M. Louda, Anne M. Parkhurst, Kate L. Bradley, Elisabeth S. Bakker, Johannes M. H. Knops, Ellen I. Damschen, Lauren M. Young

School of Biological Sciences: Faculty Publications

An exchange regarding the article: Bradley, K. L., E. I. Damschen, L. M. Young, D. Kuefler, S. Went, G. Wray, N. M. Haddad, J. M. H. Knops, and S. M. Louda. 2003. Spatial heterogeneity, not visitation bias, dominates variation in herbivory. Ecology 84:2214–2221.

Cahill et al. write:
Here we show that the experimental design and statistical analysis used by Bradley et al. (2003) do not adequately control for Type II experimental error (accepting the null hypothesis when it is in fact false). This is particularly important when responses have low effect sizes such as those previously demonstrated for visitation effects …

Cancer Incidence Among Pesticide Applicators Exposed To Atrazine In The Agricultural Health Study, Jennifer A. Rusiecki, Anneclaire De Roos, Won Jin Lee, Mustafa Dosemeci, Jay H. Lubin, Jane A. Hoppin, Aaron Blair, Michael C. R. Alavanja

United States Public Health Resources

Background: Atrazine is the most heavily applied agricultural pesticide for crop production in the United States. Both animal and human studies have suggested that atrazine is possibly carcinogenic, but results have been mixed. We evaluated cancer incidence in atrazine-exposed pesticide applicators among 53 943 participants in the Agricultural Health Study, a prospective cohort study of licensed pesticide applicators in Iowa and North Carolina.
Methods: We obtained detailed pesticide exposure information using a self-administered questionnaire completed at the time of enrollment (1993–1997). Cancer incidence was followed through December 31, 2001. We used adjusted Poisson regression to calculate rate ratios (RRs) and …

Use Of Fecal Glucocorticoid Metabolite Measures In Conservation Biology Research: Considerations For Application And Interpretation, Joshua J. Millspaugh, Brian E. Washburn

United States Department of Agriculture Wildlife Services: Staff Publications

Fecal glucocorticoid metabolite analyses are increasingly being used by a variety of scientists (e.g., conservation biologists, animal scientists) to examine glucocorticoid (i.e., stress hormone) secretion in domestic and wild vertebrates. Adrenocortical activity (i.e., stress response) is of interest to conservation biologists because stress can alter animal behavior, reduce resistance to disease, and affect population performance. The noninvasiveness of fecal-based assessments is attractive, particularly when studying endangered species, because samples can often be obtained without disturbing the animal. Despite such advantages, many confounding factors inhibit the utility of this technique in addressing conservation problems. In particular, interpretation of fecal glucocorticoid metabolite …

Historical Evidence Of Riparian Forests In The Great Plains And How That Knowledge Can Aid With Restoration And Management., Elliot West, Greg Ruark

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

While some argue that the Great Plains were dominated by grasslands and that riparian woodlands were rare, others contend that trees would logically have occurred in riparian areas due to favorable microenvironment conditions. Historically, what native plant communities were found in riparian zones of the Great Plains? The answers to this question depend to a large extent on what time period is used as a reference of pre-settlement conditions.

The U.S. Fish and Wildlife Service (1981) drew upon conditions in 1905 for insight and concluded that trees were “wholly absent” or consisted of scattered cottonwood and willow. However, such a …

The Analysis Of A Late Holocene Bison Skull From The Ashley National Forest, Utah, Kenneth P. Cannon

United States National Park Service: Publications

Executive Summary

In 2003 a partial bison skull was recovered by Ashley National Forest archeologist Brian Storm from an elevation of 3840 m (12,600 ft) AMSL in the Uinta Mountains. The partial skull consists of a portion of the frontal, occipital region, and horn cores including horn sheaths. The presence of the horn sheaths is of particular interest for the ecological information they can provide. Through the analysis of the individual cones of the horn sheath a record of the animal’s dietary and migration patterns can be obtained.

The skull was recovered downslope of Gilbert Peak in an alpine environment. …

Retrospective Isotopic Analyses Of Stellar Sea Lion Tooth Annuli And Sea-Bird Feathers: A Cross-Taxa Approach To Investigating Regime And Dietary Shifts In The Gulf Of Alaska, Keith Hobson, Elizabeth Sinclair, Anne York, James Thomason, Richard Merrick

United States Department of Commerce: Staff Publications

Stable isotope (δ¹⁵N and δ¹³C) values of individual tooth annuli of female Steller sea lions (n = 120) collected from the 1960s through the 1980s were used for retrospective analyses of temporal changes in food webs in the Gulf of Alaska and North Pacific Ocean. We also examined isotopically contour feathers of tufted puffins (n = 135) and crested auklets (n = 37) through this period to test for broader isotopic patterns indicative of whole food web changes. Steller sea lions decreased slightly in δ¹³C and increased in δ¹⁵N values, suggesting an …

Brown-Headed Cowbirds In Grasslands: Their Habitats, Hosts, And Response To Management, Jill Shaffer, Christopher Goldade, Meghan Dinkins, Douglas Johnson, Lawrence Igl, Betty Euliss

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

The brown-headed cowbird (Molothrus ater) is an obligate brood parasite whose numbers have increased in recent decades to the potential detriment of the species that they parasitize. Thus, most management efforts focus on discouraging brown-headed cowbird parasitism or controlling brown-headed cowbird populations. Keys to discouraging cowbird parasitism or controlling populations of brown-headed cowbirds in the Great Plains are maintaining large expanses of grassland, eliminating foraging areas (e.g., feedlots) and perch sites, and reducing the extent of overgrazed pastures.

Ten Suggestions To Strengthen The Science Of Ecology, Gary E. Belovsky, Daniel B. Botkin, Todd A. Crowl, Kenneth W. Cummins, Jerry F. Franklin, Malcolm L. Hunter, Anthony Joern, David B. Lindenmayer, James A. Macmahon, Chris R. Margules, J. Michael Scott

Papers in Ecology

There are few well-documented, general ecological principles that can be applied to pressing environmental issues. When they discuss them at all, ecologists often disagree about the relative importance of different aspects of the science’s original and still important issues. It may be that the sum of ecological science is not open to universal statements because of the wide range of organizational, spatial, and temporal phenomena, as well as the sheer number of possible interactions.We believe, however, that the search for general principles has been inadequate to establish the extent to which generalities are possible.We suggest that ecologists may need to …

Endangered And Threatened Wildlife And Plants: Designation Of Critical Habitat For Topeka Shiner

Endangered Species Bulletin

We, the U.S. Fish and Wildlife Service, announce the reopening of a 30-day public comment period for the proposed rule to designate critical habitat for the Topeka shiner (Notropis topeka) pursuant to the Endangered Species Act of 1973, as amended (Act). The proposed rule to designate critical habitat in the States of Iowa, Kansas, Minnesota, Nebraska, and South Dakota was published on August 21, 2002 (67 FR 54261). We herein propose critical habitat segments for Missouri and one additional segment for South Dakota, and discuss potential exclusions from critical habitat designation under the authority of section 4(b)(2). We …

Wildlife Conservation Sunflower Plots As A Dual-Purpose Wildlife Management Strategy, George M. Linz, Dionn A. Schaaf, Philip Mastrangelo, H. Jeffrey Homan, Linda B. Penry, William J. Bleier

United States Department of Agriculture Wildlife Services: Staff Publications

The National Sunflower Association has identified blackbird damage as a key reason for growers to abandon sunflower. In the 1980s, National Wildlife Research Center scientists showed that "decoy" p1antings of sunflower can significantly reduce bird damage to nearby commercial sunflower fields. For a variety of reasons, largely logistical and economic in nature, decoy sunflower fields did not become wide-spread. Over the last decade, new federal farm programs have placed more emphasis on wildlife conservation. Thus, decoy sunflower fields planted to ameliorate blackbird damage and establish habitat for wildlife might gamer broad support from both agricultural and conservation groups. We present …

Introduction To Online Ecological And Environmental Data, Virginia A. Baldwin

University of Nebraska-Lincoln Libraries: Faculty Publications

The advent of the Internet and proliferation of materials on it has brought significant and rapid change in scholarly communication. Perhaps more gradually has come the posting of research data for sharing with other researchers in the field. This volume describes several projects that have made environmental and ecological researchers' data freely available online. Librarians from the National Aeronautics and Space Administration (NASA), the United States Geological Survey (USGS), from one regional agency based in Oregon, one university, and one research corporation describe aspects of the online data projects developed by their respective institutions. A sixth paper, from a librarian …

The Wetland Continuum: A Conceptual Framework For Interpreting Biological Studies, Ned H. Euliss Jr., James W. Labaugh, Leigh H. Fredrickson, David M. Mushet, Murray K. Laubhan, George A. Swanson, Thomas C. Winter, Donald O. Rosenberry, Richard D. Nelson

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

We describe a conceptual model, the wetland continuum, which allows wetland managers, scientists, and ecologists to consider simultaneously the influence of climate and hydrologic setting on wetland biological communities. Although multidimensional, the wetland continuum is most easily represented as a two-dimensional gradient, with ground water and atmospheric water constituting the horizontal and vertical axes, respectively. By locating the position of a wetland on both axes of the continuum, the potential biological expression of the wetland can be predicted at any point in time. The model provides a framework useful in the organization and interpretation of biological data from wetlands by …

Curassows, Guans And Chacalacas: Status Survey And Conservation Action Plan (2000-2004), Stuart D. Strahl, Daniel M. Brooks

Galliformes Specialist Group and Affiliated Societies: Reports and Other Materials

Executive Summary

Introduction

• Scope, structure, and objectives of the plan
• Rationale for the action plan
• Relevance of the action plan to general biodiversity conservation
• Cracid Specialist Group activities, strategy, and history
• Symposia and workshops
• Cracid Specialist Group publications
• Other activities related to cracid conservation
• Cracid natural history
• Evolution and ecology
• Biogeography, distribution, and habitat association
• The role of cracids in ecosystems
• Cracids as biological indicators of ecosystem health
• Socio-economic importance of cracids
• Sustainable use
• Potential for ecotourism
• Taxonomic definitions used in this action plan
• Threats to cracids
• Hunting pressure
• Habitat destruction
• Lack of knowledge
• Action needed to secure the future …

Beyond Ecology: Bugs Reveal The Deep Roots Of Grassland Ecoregions, K. G.A. Hamilton

Proceedings of the North American Prairie Conferences

Northern grassland faunas that were most affected by glaciation, induced climate shifts include more than 225 endemic phytophagous bugs (leafhoppers and related insects, the Homoptera,Auchenorrhyncha) on Canadian plains, and another 275 in Pacific Northwest intermontane grasslands. These exceptionally rich endemic faunas include many insect,plant associations common to related species of bugs, suggesting adaptation to certain environmental factors that persisted over millions of years despite radical environmental changes induced by glacial advances and retreats. Smaller, but significant, endemic faunas of Homoptera,Auchenorrhyncha in other glaciated areas also reveal patterns of ancient ecological areas. Groups of these grassland,endemic bugs are common to grassland …

Influence Of Matrix Elements On Prairie-Inhabiting Curculionidae, Tenebrionidae, And Scarabaeidae In The Palouse, Timothy D. Hatten, Sandford D. Eigenbrode, Nilsa A. Bosque-Pérez, Sarah Gebbie, Frank Merickel, Chris Looney

Proceedings of the North American Prairie Conferences

It is well established that the invertebrate community in cropland under conservation-tillage (consT) is often enriched relative to the community under conventional-tillage (CT) systems. The question posed in this research is whether consT contributes to the maintenance of regional biodiversity and to the conservation of prairie-inhabiting species in agriculturally dominated landscapes that contain prairie remnants. During 2002, we sampled the grounddwelling beetle fauna of remnant Palouse prairie and surrounding cropland (under CT and consT) in the Palouse region of northwestern Idaho and southeastern Washington. Biological diversity of the representative taxa-Curculionidae (weevils), Tenebrionidae (darkling beetles) and Scarabaeidae (scarab beetles)-is significantly higher …

Potential Habitat Factors Influencing Carrion Beetles Communities Of Palouse Prairie Remnants, Chris Looney, Benjamin T. Caldwell, Timothy D. Hatten, Christopher Lorion, Sanford D. Eigenbrode

Proceedings of the North American Prairie Conferences

The bunchgrass prairies of the Palouse region in eastern Washington state and adjacent Idaho were almost completely converted to agriculture in the past century. Today, prairie habitat exists only on small remnants scattered across the landscape. The invertebrate fauna of these habitat remnants is poorly known, both in terms of species diversity and community composition. Pitfall traps baited with carrion were used to sample carrion beetles (Coleoptera: Silphidae) during June and July of 2003. Prairie remnants were selected based on size to test whether habitat area influenced the diversity of this important insect community. Three size classes were identified; greater …

Adapting A Floral Biogeography Model To Prairie-Dependent Lepidoptera, Eric H. Metzler, John A. Shuey, Leslie A. Ferge, Richard A, Henderson, Paul Z. Goldstein

Proceedings of the North American Prairie Conferences

Analysis of data collected for a study of prairie dependent Lepidoptera in the northern tallgrass prairies showed four distributional patterns. A logical distributional pattern links species' distribution, i.e. Catocala abbreviatella, to larval host plants. Absence of larval host plant data, which is the case for most species of moths, requires inference based on habitat data of known specimens, i.e. Tarachidia binocula, or in the case of infrequently encountered species, i.e. Crambus murellus, capture data for a limited number of specimens. A fourth distributional pattern, i. e. Atrytone arogos, can be explained by hypotheses which explain the …

Mediterranean Landscape Archaeology Past And Present, Effie F. Athanassopoulos, Luann Wandsnider

Department of Anthropology: Faculty Publications

Recent studies of Mediterranean landscapes have emphasized their diversity, their fragmentation, and the high degree of contact between their diverse areas, that is, their connectivity (Horden and Purcell 2000). Moreover, the Mediterranean landscape record is recognized for its length and richness and the opportunity it offers to study long-term interaction between humans and their landscape, however landscape is defined. At the same time, the particular histories of archaeological perspectives that have dominated fieldwork in the region make it difficult to compare with other areas, for example, the New World. Thus, with this volume, our intent is to address issues of …

Response Of Grassland Birds To Fire On A Wisconsin Sand Prairie Over An 18-Year Period, Greg Geller, David Sample, Rich Henderson

Proceedings of the North American Prairie Conferences

The relative abundance of grassland birds was estimated on an 81-ha (200-acre) dry to dry-mesic sand prairie in south, west Wisconsin over an 18-year period (1987-2004). Birds were surveyed three times during the breeding season on seven, 2-ha (5-acre) strip transects in six different burn units. We compared results to time since fire and other habitat features. The average rotation of prescribed fires in the burn units ranged from three to six years. Seven species were selected for detailed analysis. These were grasshopper sparrows (Ammodramus savannarum),-18-year average of 1.33 birds per ha, field sparrows (Spizella pusilla) …

The Effects Of Habitat Resolution On Models Of Avian Diversity And Distributions: A Comparison Of Two Land-Cover Classifications, Joshua Lawler, Raymond O'Connor, Carolyn Hunsaker, K. Bruce Jones, Thomas Loveland, Denis White

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

Quantifying patterns is a key element of landscape analysis. One aspect of this quantification of particular importance to landscape ecologists is the classification of continuous variables to produce categorical variables such as land-cover type or elevation stratum. Although landscape ecologists are fully aware of the importance of spatial resolution in ecological investigations, the potential importance of the resolution of classifications has received little attention. Here we demonstrate the effects of using two different land-cover classifications to predict avian species richness and the occurrences of six individual species across the conterminous United States. We compared models built with a data set …

Effects Of Distance From Cattle Water Developments On Grassland Birds, Andrea L. Fontaine, Patricia L. Kennedy, Douglas H. Johnson

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

Many North American grassland bird populations appear to be declining, which may be due to changes in grazing regimes on their breeding areas. Establishment of water developments and confining cattle (Bos taurus L.) to small pastures often minimizes spatial heterogeneity of cattle forage consumption, which may lead to uniformity in vegetative structure. This increased uniformity may provide suitable habitat for some bird species but not others. We assessed how cattle use, vegetative structure, and bird population densities varied with increasing distance from water developments (0-800 m) on the Little Missouri National Grassland (LMNG) in North Dakota. Lark buntings ( …

Genetic Diversity And Structure Of The Fisher (Martes Pennanti) In A Peninsular And Peripheral Metapopulation, Samantha M. Wisely, Steven W. Buskirk, Gregory A. Russell, Keith B. Aubry, William J. Zielinsky

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

Evolutionary processes can be strongly affected by landscape features. In vagile carnivores that disperse widely, however, genetic structure has been found to be minimal. Using microsatellite DNA primers developed for other mustelids, we found that populations of a vagile forest carnivore, the fisher (Martes pennanti), exhibit high genetic structure (F_ST = 0.45, SE = 0.07) and limited gene flow (Nm < 1) within a .1,600-km narrow strip of forested habitat; that genetic diversity decreases from core to periphery; and that populations do not show an equilibrium pattern of isolation-by-distance. Genetic structure was greater at the periphery than at the core of the distribution and our data fit a 1-dimensional model of stepping-stone range expansion. Multiple lines of paleontological and genetic evidence suggest that the fisher recently (<5,000 years ago) expanded into the mountain forests of the Pacific coast. The reduced dimensionality of the distribution of the fisher in western coastal forests appears to have contributed to the high levels of structure and decreasing diversity from north to south. These effects were likely exacerbated by human-caused changes to the environment. The low genetic diversity and high genetic structure of populations in the southern Sierra Nevada suggest that populations in this part of the geographic range are vulnerable to extinction.

Forest Harvest Can Increase Subsequent Forest Fire Severity, Carter Stone, Andrew T. Hudak, Penelope Morgan

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

The USDA Forest Service is progressing from a land management strategy oriented around timber extraction towards one oriented around maintaining healthy forested lands. The healthy Forest Initiative promotes the idea of broadscale forest thinning and fuel treatments as an effective means for mitigating hazardous fuel conditions and, by extension, fire risk. Fuels mitigation is proactive while fire suppression is reactive and expensive. Costs associated with suppressing large wildfires, as occur in the western USA with annual regularity, are astronomical and routinely exceed fire suppression budgets. It is not difficult to demonstrate that treating forest fuels is more cost effective than …

Less Waste Corn, More Land In Soybeans, And The Switch To Genetically Modified Crops: Trends With Important Implications For Wildlife Management, Gary L. Krapu, David A. Brandt, Robert R. Cox Jr.

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

American agriculture has provided abundant high-energy foods for migratory and resident wildlife populations since the onset of modern wildlife management. Responding to anecdotal evidence that corn residues are declining in cropland, we remeasured waste corn postharvest in the Central Platte River Valley (CPRV) of Nebraska during 1997 and 1998 to compare with 1978. Post-harvest waste corn averaged 2.6% and 1.8% of yield in 1997 and 1998, respectively. After accounting for a 20% increase in yield, waste corn in 1997 and 1998 was reduced 24% and 47% from 1978. We also evaluated use of soybeans by spring-staging sandhill cranes ( Grus …

Coyote And Wolf Habitat Use In Northwestern Montana, Wendy M. Arjo, Daniel H. Peltscher

United States Department of Agriculture Wildlife Services: Staff Publications

Being a habitat generalist is an adaptation suategy that has allowed the coyote to expand its range. As wolves reestablish, or are reintroduced, resident populations of coyotes may change habitat use. We compared habitat use between coyotes and wolves in Glacier National Park after successful recolonization by wolves. Two wolf oacks and nine coyotes were monitored from June 1994 throueh June 1997 to determine habitat use in northwestern Montana. Wolves used habitat types within their home ranges in proportion to availability during the winter, but not the summer when more open areas and burned forests were used. Most coyotes used …

Effects Of Management Practices On Grassland Birds: American Bittern, Jill A. Dechant, Marriah L. Sondreal, Douglas H. Johnson, Lawrence D. Igl, Christopher M. Goldade, Amy L. Zimmerman, Betty R. Euliss

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

Information on the habitat requirements and effects of habitat management on grassland birds were summarized from information in more than 4,000 published and unpublished papers. A range map is provided to indicate the relative densities of the species in North America, based on Breeding Bird Survey (BBS) data. Although birds frequently are observed outside the breeding range indicated, the maps are intended to show areas where managers might concentrate their attention. It may be ineffectual to manage habitat at a site for a species that rarely occurs in an area. The species account begins with a brief capsule statement, which …

Great Plains Ecosystems: Past, Present, And Future, Fred B. Samson, Fritz L. Knopf, Wayne Ostlie

United States Geological Survey: Staff Publications

Little questions exists that the main bodies of North American prairie (i.e., the tall-grass, mixed, and shortgrass) are among the most endangered resources on the continent. The purpose of this paper is to provide a past and present biological base- line by which to understand North American prairies and to provide a platform for future conservation. Events both immediate to the end of the Pleistocene and historic suggest that the present grassland conditions are different from those within which most of the grassland organisms evolved. Our analysis suggests that few grassland landscapes remain adequate in area and distribution to sustain …

Predicting Predation Efficiency Of Biocontrol Agents: Linking Behavior Of Individuals And Population Dynamics, Brigitte Tenhumberg

School of Biological Sciences: Faculty Publications

Behavioral ecology and population ecology are two separate branches of ecology; studies linking the effect of individual behavior and population dynamics are rare. This paper connects a stochastic optimal foraging model of insect predators with an age structured population model of its prey. I modeled syrphid larvae feeding on cereal aphids, an interaction critical to cereal crops in Germany. The key stochastic element in this model is the foraging success of predators, which influences survival and developmental time of predators and mortality of the prey population. The model predicts that the level of control incurred by predators is highest if …

The Double-Edged Sword Of Biological Control In Conservation And Restoration, Svata M. Louda, Peter Stiling

Svata M. Louda Publications

The most fundamental question in considering deliberate introductions of exotic species against invasive species is whether the outcomes can be predicted precisely enough a priori to know with some certainty that the benefits will outweigh the environmental costs. This issue is obscured by reiteration of an overly simplistic description of the ecology underlying biological control. Classical biological control is not a simple exercise in “community re-assemblage” (Hoddle 2004); it involves the introduction of alien organisms into new species assemblages, in new physical environments, and without the rest of their foodweb. Predicting the outcome of such introductions is infinitely more complex …

Mark–Recapture And Behavioral Ecology: A Case Study Of Cliff Swallows, C. R. Brown, Mary Bomberger Brown

School of Biological Sciences: Faculty Publications

Mark–recapture and behavioral ecology: a case study of Cliff Swallows.— Mark–recapture and the statistical analysis methods associated with it offer great potential for investigating fitness components associated with particular behavioral traits. However, few behavioral ecologists have used these techniques. We illustrate the insights that have come from a long–term mark–recapture study of social behavior in Cliff Swallows (Petrochelidon pyrrhonota). The number of transient swallows passing through a colony per hour increased with colony size and was responsible in part for increased rates of ectoparasite introduction from outside the group into the larger colonies. Annual survival probabilities of …