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The nature of natural history as represented in the American Midland Naturalist has changed during its eight decades of publication. Although subject matter became increasingly diverse, the emphasis shifted from taxonomic and distributional studies to ecology. Geographic coverage extended beyond the American midlands, generations of authors came and went and the titles and terminology illustrate the changing face of natural history. Changes in length of articles, sources of funding and questions addressed are evident.
During the past century, Barred Owls (Strix varia) expanded their range from forests east of the Great Plains to forests throughout most of central and western North America. Here in Part I, I map more than 12,500 records of Barred Owls in their expanded range from the earliest records to the present, draw the species' distribution in its expanded range and infer the general timing and flow of the range expansion. Evidently, Barred Owls originally traveled across the northern Great Plains via the forested riparian corridors of the Missouri, Yellowstone and Musselshell rivers into east-central Montana by 1873. From there, they accessed western forests in southwestern Montana (1909), moved to northwestern Montana (1922) and then expanded their range in two general directions. They moved north and east to northern Alberta (1934) and Saskatchewan (1948) where they apparently encountered other Barred Owls coming westward from Manitoba. They also moved north to northern British Columbia (1943), southeastern Alaska (1967) and Northwest Territories (1977), and west and south to Washington (1965), Idaho (1968), Oregon (1972) and California (1976). In Part II (Livezey, in press), I explore what prevented Barred Owls from expanding their range westward during recent millennia and what allowed them to do so during the past century.
Wildlife species can serve as biomonitors of environmental health and are prognostic of ecotoxicological consequences when contaminants are introduced into the environment. Small mammals, particularly rodents, comprise the majority of indicator species used in terrestrial biomonitoring studies; however, many biomonitoring studies address acute effects over relatively short periods. We still know little regarding effects of chronic exposure to contaminants on small mammals. The overall goal of this study was to determine ecological characteristics of small mammal communities inhabiting a heavy metal contaminated site, Tar Creek Superfund Site, compared to reference sites located in northeastern Oklahoma over a 2 y timeframe. Primary hazardous materials present at Tar Creek Superfund Site include lead, zinc and cadmium. Mark-recapture techniques were employed to test the hypothesis that structure and composition of small mammal communities inhabiting this contaminated site would be significantly altered compared to uncontaminated reference sites. Contaminated and reference sites were similar in vegetation compositional characteristics. Small mammal communities inhabiting Tar Creek Superfund Site had reduced species diversity, including richness and evenness, compared to reference sites. Furthermore, communities within Tar Creek Superfund Site were dominated by a single species, Peromyscus leucopus (white-footed mouse). Species composition was different between contaminated sites and reference sites as evidenced by detrended correspondence analysis, with contaminated sites being more similar to each other than to either reference site. No direct link between site contamination and disparities among most ecological characteristics could be established.
Food habits of cougars (Puma concolor) in North America have been documented for western populations in the United States, Canada and Mexico. Most studies assessed diets of cougars occupying typical habitats, and within established populations. We evaluated food habits of cougars in prairie and agricultural landscapes in the Dakotas (regions that had been devoid of the species for roughly a century) located well outside of known resident populations. We obtained stomach and gastrointestinal (GI) tracts from 14 cougars (10 male; 4 female) from 2003–2007, and evaluated contents via frequency of occurrence (%) of various prey items. Deer (Odocoileus spp.) had the highest frequency of occurrence (50.0%). Other native mammalian prey included jackrabbit (Lepus townsendii, L. californicus), porcupine (Erethizon dorsatum), beaver (Castor canadensis), badger (Taxidea taxus), mink (Mustela vison) and rodent species (e.g., vole). No domestic livestock species were documented as part of the cougar diet in the Dakotas, although remains of domestic housecat (Felis silvestris) were found in GI tracts of two animals. Based on our results, cougars occupying non-typical, newly recolonized habitats were successfully adapting predation techniques for capture of natural and newly confronted prey species. The wide range of prey encountered suggested that prey was being obtained opportunistically in prairie and agricultural landscapes of the Dakotas.
Many warmwater streams in the midwestern United States have been negatively influenced by human land-use practices. From Jun. through Aug. 2002 and 2003, tributaries (n = 50) of the upper Wabash River basin, Indiana, were sampled to investigate ecosystem health and integrity. Stream fish and macroinvertebrates were sampled along with in-stream habitat according to National Water-Quality Assessment Program protocols to examine relationships among fish community structure, benthic macroinvertebrate assemblages, physical-habitat complexity and water chemistry under varying land-use practices. Stream fish abundance was best explained by in-stream habitat quality (QHEI), watershed area and the amount of forested land use upstream of each sampling site. Overall index of biotic integrity (IBI) scores were low (mean = 35.58; range, 20 to 52), and varied predictably by riparian land-use type. The abundance of benthic macroinvertebrate taxa was best explained by the substrate QHEI metric (λ = 0.24; P = 0.005). Macroinvertebrate community index (ICI) scores showed more variability than IBI scores (mean = 20.40; range, 0 to 36). In-stream habitat quality (QHEI) was directly related to riparian land-use practices. Forested sites had higher QHEI scores than fallow field and agricultural sites due to increased habitat heterogeneity, large-woody debris loading and larger substrate sizes. The best model for predicting IBI scores incorporated both watershed and reach-scale variables combining slope and erosion power with maximum depth, percent canopy closure, percent fine substrates, degree of channelization and LWDI (r2 = 0.24; adjr2 = 0.19). Reach-scale variables (i.e., QHEI score, stream width, the proportion of unstable banks and percent fine substrates) best predicted ICI scores (r2 = 0.69; adjr2 = 0.66). Based on these results, we recommend that resource managers incorporate both biotic and abiotic factors at various temporal and spatial scales to predict the effects of land-use practices on community health in agriculturally dominated, warmwater streams.
Taphonomic studies of extant turtles are useful for interpreting the taphonomy of fossil turtles. In order to provide modern comparators for fossil turtle sites, we have characterized two modern turtle (Chrysemys picta) deathsites; one in northwestern Nebraska and one in southwestern South Dakota. During these studies we characterized carapace position (up or down), presence or absence of non-shell elements, relative spatial position of the turtles and presence of shell disturbances (lesions). In the Trunk Butte site (Nebraska), six turtles were in carapace up position, five were in carapace down and one was not determinable. In addition, seven of those turtles contained some non-shell elements and five had indeterminable non-shell element status. At the Buffalo Gap site (South Dakota), four were carapace down, two were carapace up and three were not determinable for that character. Six of these had non-shell elements associated with them and three had no non-shell elements. The occurrence of turtles in the carapace down position suggests either the presence of medium to large scavengers able to overturn a turtle or that the turtle died while in the water and overturned while sinking. The spatial distributions of turtles in the two modern sites were also plotted and compared to that of two Whitney (Brule Formation, White River Group) and one Chadron (White River Group) site to address the hypothesis that the fossil assemblages were associated with small ponds. The results suggest that the fossil turtle sites were not the result of death events associated with small ponds, nullifying that hypothesis.
Because of the declines in grassland bird populations across North America, many state and federal agencies are making efforts to manage for grassland bird populations, particularly in a landscape context. To effectively manage for grassland birds, we need to understand how grassland bird species use different habitat types within landscapes. We determined the densities of grassland birds in remnant prairie patches and Conservation Reserve Program (CRP) fields and compared those to managed agricultural habitat types (pastures, alfalfa hay and strip crop fields). We also investigated whether densities were associated with landscape features. This study took place in the Military Ridge Prairie Heritage Area (MRPHA) in southwestern Wisconsin May–Jul. 2002 and 2003. Land use in the MRPHA is primarily agricultural, with a relatively large portion of the land in pasture, hay, small grains and idle grasslands enrolled in CRP and relatively few acres of corn and soybeans compared to other areas of the state. This area also has numerous remnant prairie patches. We used line transect surveys to measure species density in the different habitat types. The five most common grassland species in the study area were bobolink (Dolichonyx oryzivorus), eastern meadowlark (Sturnella magna), grasshopper sparrow (Ammodramus savannarum), Henslow's sparrow (A. henslowii) and Savannah sparrow (Passerculus sandwichensis). Densities did not differ between years. Habitat type was the most important factor associated with species density. Bobolink densities were greatest in hay fields, followed by CRP fields. Eastern meadowlark densities were greatest in CRP fields, remnant prairie patches and pastures. Grasshopper sparrow densities were greatest in remnant prairie, Henslow's sparrow densities were greatest in CRP fields and remnant prairie and Savannah sparrow densities were greatest in pasture and hay fields. There was no evidence that densities of any of the grassland species increased with site size within habitat type. Only bobolink and eastern meadowlark were associated with a landscape variable; both species' densities in the field were positively associated with proportion of grassland within 200 m of the site. When managing for grassland birds in a landscape with a large amount of grassland, a diversity of habitat types will be needed to conserve grassland birds as a group.
Riparian zones are hotspots of wildlife diversity and also particularly attractive for housing development. Landscaping associated with homes contributes to a wide range of lakeshore vegetation structures. Based on calling surveys in Northern Wisconsin, we investigated effects of lakeshore vegetation structure on bird diversity and frog abundance at three spatial scales: parcel (30 m of shoreline), whole-shore (340 m of shoreline) and whole-lake scales. For parcel and whole-shore scales, we selected sites paired by lake: 10 sites with an intact understory vegetation layer and 10 sites with a cleared understory. Green frog (Rana clamitans) abundances were somewhat related to presence of forest understory at the parcel scale. More clearly, we found higher avian species richness at sites with intact understory vegetation than those without, and increasing richness with canopy coverage. Aerial insect abundances, which were also higher at sites with an intact understory, may help explain bird distributions. Our results suggest that riparian understory landscaping at the scale of individual parcels can alter local bird communities.
We mapped the biogeographical distribution of chloroplast haplotypes in northern red oak (Quercus rubra L.) to test the hypotheses that the founder effects during postglacial migration will result in a latitudinal gradient of haplotype diversity with exhaustion of haplotype richness at the extreme northern edge of the range. PCR-RFLP markers for 23 populations of Q. rubra in old growth and minimally disturbed forests across 13,000 km2 of the contemporary range revealed only four of the five haplotypes detected previously at 12 sites in Indiana. The four northernmost populations were fixed for either haplotype I or haplotype II, the two most common haplotypes. Haplotype richness declined poleward, but the biogeographical pattern of 829 haplotypes across the 35 sites did not clearly indicate postglacial migration routes along latitudinal gradients from the southern edges of the study area. Although Q. rubra and the European white oak Q. robur L. are both early successional species that recolonized vast areas as the glaciers retreated, the data indicate that Q. rubra has lower chloroplast haplotype richness, suggesting that the population dynamics of Q. rubra prior to or during Pleistocene climate fluctuations may have differed from the population dynamics of the European white oak taxa.
Science is made of building blocks, that is, one piece of knowledge leads to or combines with another piece ad infinitum. Consequently, for the process of science to work, everyone involved must be able to count on everyone else to conduct their work in a straightforward manner involving no deception. As scientists, authors, reviewers and editors have the responsibility to the global scientific community to help train the next generation of scientists to recognize the differences between ethical and unethical behaviors. To assist in this process discussions are included of the obligations and limitations of authors, reviewers and editors. Also, included are discussions concerning usage of copyrighted materials, advocacy, coauthorship, conflicts of interest, publishing rights and responsibilities and characteristics of a good review. To assist understanding of these concepts, are a series of hypothetical Case Studies intended to allow students of science to consider, discuss and challenge their thinking related to the integrity of research and publishing in science.
Exotic invasive plant species differ in their effects on indigenous vegetation as evidenced by research evaluating community response to their removal. We used a removal approach to quantify the response of a mesic woodland to the removal versus retention of an invasive plant, Hesperis matronalis (dame's rocket) from paired treatment plots over 3 y. Cover of H. matronalis did not differ between control and treatment plots prior to removal, declined in the removal plots and remained significantly lower in cover compared to the control plots. Removal did not significantly affect species richness and species diversity (evenness, Shannon and Simpson) at the plot scale, but did result in increased species richness overall in the removal plots in the last sampling year when compared to control plots. Non-metric multidimensional scaling ordination analysis indicated a significant compositional change in the spring plant composition of plots over the 3 y, reflecting an increase in exotic woody species. Exotic woody plants, especially Rosa multiflora and Euonymus alatus, increased in cover in response to H. matronalis removal. In the 3 y, neither native nor exotic forbs, nor native woody plants responded to the removal of H. matronalis in a statistically significant manner. The increasing cover of woody invasive plants in response to the removal of H. matronalis has important management implications for restoration of degraded communities.