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Most studies of white-tailed deer (Odocoileus virginianus Zimm.) herbivory focus on a few forb species or single sites in forest plant communities. However, managers require assessments of herbivory impacts across varying deer densities and in multiple plant communities, including wetlands and savannas where there is limited knowledge about the impacts of deer on herbaceous vegetation. During 2008 and 2009, we investigated deer herbivory impacts at six forest preserves near Chicago, Illinois. We sampled 192 browse transects in two forest, two savanna, and two wetland sites; sites were paired within each plant community type based on deer density (i.e., high vs. low). We used plant community metrics (i.e., percent non-vegetated ground cover, species diversity and evenness, and floristic quality) to quantify and compare herbivory impacts on vegetation between preserves. We observed higher grass cover (0.001 < P < 0.012), lower species diversity (0.001 < P < 0.041), and lower floristic quality (0.001 < P < 0.030) in preserves containing higher deer densities (22–29 deer/km2; low-density populations were 6–19 deer/km2) for all three plant community types. Managers should be aware that deer are negatively affecting forest, savanna, and wetland plant communities at densities of > 20 deer/km2 in the Great Lakes region. We further suggest managers use plant community metrics, rather than single indicator species, to monitor deer herbivory.
We evaluated the effectiveness of protected areas in the Baja California Peninsula for the conservation of endemic species of reptiles, birds, and mammals by using a combination of approaches. We built a collection database consisting of 7912 unique specimens from 826 sites. We found 42 endemic species on the peninsula: 17 microendemics, 13 mesoendemics, and 12 macroendemics. Our findings show that 37 endemic species (88% of the total endemics) are found within the boundaries of these eight protected areas, and five microendemics are gap species (unrepresented). Complementarity values show a low level of diversity between the endemic vertebrate faunas of the adjacent areas, Valle los Cirios and Vizcaino (ICC = 0.44). A much higher complementarity (ICC = 0.86) was found in the Valle los Cirios and La Laguna areas, more than 400 km apart. The National Park Constitucion de 1857 has no terrestrial endemic vertebrates within its boundaries. About 60% of the peninsular endemic vertebrates are included in the Mexican list of species at risk. We identified areas of high concentration of terrestrial-endemic vertebrate species in the Baja California Peninsula: one in the north in the San Telmo-San Quintin region, a second in Planicies de Magdalena, and a third in Sierra La Giganta in the middle south, and a region in Sierra La Laguna in the southern part of the peninsula. Our results provide a robust diagnosis of the effectiveness of the protected areas for the conservation of endemic vertebrates that can be useful for further studies and for improving the protection of these regional biodiversity elements.
Whitebark pine (Pinus albicaulis) is a fundamental component of alpine and subalpine habitats in the Greater Yellowstone Ecosystem. The magnitude of current white pine blister rust (WPBR) infection caused by the pathogen Cronartium ribicola and mountain pine beetle (MPB; Dendroctonus ponderosae) impacts, combined with the effect of climate change on beetle population dynamics, are placing this foundation species in a precarious state. We collected stand- and tree-level data in three whitebark pine systems in the southern Greater Yellowstone Ecosystem to evaluate current conditions and to determine how characteristics of individual whitebark pine trees, including the presence and severity of white pine blister rust, influence host selection by the MPB. Data revealed that 45% of all whitebark pine trees sampled were dead. In addition, 67% of all trees sampled were attacked by MPB, 83% were infected with WPBR, and 62% were affected by both. Whitebark pine trees that were selected as hosts by MPB exhibited significantly greater blister rust severity than trees that were not selected. Multiple logistic regression analyses identified a complex set of tree characteristics related to host selection by MPB; in addition to rust severity, stand type (mixed species or pure whitebark pine) and tree diameter were also significant predictors of selection. The interaction among MPB selection patterns, blister rust severity, tree diameter, and stand type quantified in this study will likely continue to influence the disturbance pattern and severity in whitebark pine ecosystems in the Greater Yellowstone Area. Understanding these patterns is critical to successful management of whitebark pine forests in this region.
Prairie fens are unique in their high plant and animal diversity; however, many are currently threatened by the invasion of exotic glossy buckthorn (Frangula alnus). Land managers and conservationists have observed a variety of qualitative changes in prairie fen after F. alnus invasion, but these observations have not been previously quantified. Here, we contrast abiotic and plant community parameters in areas of a Michigan prairie fen invaded by buckthorn with that of uninvaded references sites within the same fen. Our results document a variety of significant differences including: lower soil pH, fewer vegetative hummocks, less light availability, lower plant coefficient of conservatism, less total plant cover, and lower graminoid relative abundance in invaded versus uninvaded areas. We also investigated the buckthorn invasion process by examining abiotic and plant community differences within partially invaded plots. In such plots, F. alnus-invaded areas had significantly greater percent soil organic matter, fewer vegetative hummocks/m2, and lower mean coefficient of plant conservatism. We propose that F. alnus may be facilitating its own invasion of fen habitats and that resulting hummock degradation may pose a long-lasting detriment to fen biodiversity. We anticipate that wetland managers will be able to use this study to provide a baseline against which fen restoration success can be gauged.
Culturally modified trees (CMTs) are trees with scars that reflect human utilization of forested ecosystems. Some CMTs can reveal unique knowledge of native cultures and insight to peoples' subsistence and land use in the past, and are mostly to be found in protected areas since they contain very old trees. In this study, we examine attributes and the spatial and temporal distribution of bark-peeled trees, and present forest structure in two remnant ponderosa pine forests (Pinus ponderosa P. & C. Lawson) in western Montana. We also wanted to use an alternative method of dating CMTs and initiate a broader discussion of threats to such trees and needs for sustaining and protecting them. In total, 343 bark-peelings were recorded on 274 living and dead trees. Our results show that only certain trees were selected for harvest. Nearby trees of similar size and age were not used. The age estimation indicates that the bark-peelings were performed from the mid 1600s until the early 1900s. Today the forest at both study areas is generally low in density and all-aged with very old individual trees. They consist of a mosaic of uneven-aged tree groups and individual trees of various ages. We conclude that the abundance and density of bark-peeled trees at the study areas exceed values reported in most other North American studies (formally protected forests included), that the two areas represent different harvest areas for ponderosa pine inner bark, and that CMTs need to be recognized both as ecologically and culturally valuable features of old ponderosa pine forests.
The Klamath-Siskiyou Ecoregion has been a refuge for species during past climate change events, but current anthropogenic stressors are likely compromising its effectiveness as a refugium for this century's projected changes. Reducing non-climate stressors and securing protection for large, complex landscapes are important long-term actions to alleviate climate change impacts on biodiversity. Equally important is the immediate protection of a network of climate change microrefugia, particularly old growth and intact forests on north-facing slopes and in canyon bottoms, lower- and middle-elevations, wetter coastal mountains, and along elevational gradients. Such areas provide local opportunities for vulnerable species to persist within the ecoregion. We identify a provisional set of 22 highest-priority and 40 high-priority microrefugia that occur mostly outside of existing protected areas and along wetter and lower elevations of the ecoregion. Proposed reserve designs, if fully implemented, would capture most of the recommended microrefugia, although we found 11 important gaps. Most of the region's biodiversity, endemic species, and species vulnerable to climate change are invertebrates, non-vascular plants, and fungi that are largely restricted to persistently cool and moist late-successional forests. Opportunities for climate change response for vulnerable taxa will necessarily be local due to a limited capacity of many species to move to new habitat, even over relatively small distances where land use practices create inhospitable conditions. The ecoregion's distinctive and endemic serpentine-substrate flora also is at risk and possible refugia are sites that will retain wet soil conditions, such as seeps and bogs.
The Palouse Prairie of eastern Washington State and adjacent northern Idaho is an endangered ecosystem. Like other arable North American grasslands, the prairie was mostly converted to agriculture in the late 1800s, and native habitat is today highly fragmented within a matrix of production agriculture. Government and conservation groups are beginning conservation action in the region, but lack information regarding the number and nature of the prairie remnants. We used high-resolution aerial photography to identify potential prairie remnants in the southern half of the Palouse and describe their physical characteristics. We found that although there are many potential remnants, they tend to be small (most less than 2 ha) and have high perimeter-area ratios. Potential remnants are disproportionately found on rocky and shallow soils in the region, with only a few located on the deepest, most agriculturally valuable soil types. The remnants occur predominantly in a few large clusters near rivers and rocky buttes, and over half are within 150 m of the next nearest remnant. Almost all remnants are privately owned. The high number and clustered distribution of the remnants suggest a conservation strategy for the Palouse may be based on developing a network of small reserves. This may be best implemented at the county level through outreach efforts and partnerships with private landowners.
Organizations and governments at all levels have set goals for the reduction of greenhouse gas (GHG) emissions and have begun to work toward achieving these goals in an effort to mitigate global climate change. The City of Austin, in Travis County, Texas, has set the goal of reducing greenhouse gas emissions to 20% below 1990 levels by the year 2010. The City's Carbon Dioxide Reduction Strategy, drafted in 1997, identified aggressive strategies for reducing GHG emissions; however, carbon sequestration in natural systems was not considered as an option. I conducted a literature review to assess the carbon sequestration potential of the City of Austin's municipally-owned natural areas with respect to Travis County CO2 emissions and to identify strategies for increasing rates of carbon capture while also meeting the federal permit or municipal bond obligations of some of these lands. An analysis of 22 studies indicates that the City of Austin's natural areas are likely functioning as carbon sinks but sequestration is minimal relative to regional emissions. Carbon sequestration by Austin's natural areas is not likely to offset more than 1.6% of Travis County's year-2007 emissions. Sequestration can be improved, however, while also achieving or enhancing primary ecological management goals. Protection of soil carbon pools via land conservation is a critical first step in preventing ecosystem carbon loss and assuring that ecological management can maintain and improve sequestration rates long-term. Ecosystem carbon management techniques include prescribed fire, afforestation, rotational grazing, and plant diversity improvement.
The birds at the vicinity of the ancient town Hasankeyf (South-eastern Turkey) have been documented by a systematic survey spanning nearly one and a half years and also by casual observations afterward. A total of 133 bird species have been detected in the study area, about 60% of which were observed in spring. Nearly two-thirds of the bird species are native or summer migrants and 72 are at least potential breeders in the area. Twenty-one species of diurnal raptors were detected. Five globally and 25 regionally threatened species have been recorded. Main habitats used are the river and riparian zone, shrub, steppe, and steep rocky mountain; and around 33% of the breeding species use rocky slopes and cliffs while 11 % use riverine formations for their nesting. The area still has special natural habitats for birds, whose breeding are largely dependent on rocks which form steep walls on the river. In spite of all this richness, the wildlife in the area is strongly threatened by a highly debated big dam project, which is part of the most comprehensive regional development project of Turkey.
The Milwaukee County Parks/University of Wisconsin Extension's Natural Areas Program, located in Milwaukee County, Wisconsin, undertakes all the standard natural resource management activities. However, it places special emphasis on developing future natural resource managers. In this paper, I discuss the process the program undertakes to create well-rounded young professionals in a complicated urban natural areas management setting.
Edge effect is the change in forest structure and composition from the forest edge to the interior and has many conservation implications. We investigated whether sapling density, size, shade tolerance, and species composition, as well as microclimatic conditions, varied depending on proximity to, and aspect of, the forest edge. Across a small (2.25 ha), roughly square, forest fragment surrounded by agriculture, we measured density, size, and species composition of saplings less than 8.3 cm dbh, as well as light intensity, temperature, percent soil moisture, and relative humidity. To test for possible nutrient enhancement on the edges due to agricultural practices, we analyzed soil samples for differences in soil nutrients and pH between the edges and the interior. Both north and south edges had significantly higher sapling density and light intensity and lower average sapling size than the interior of the forest. Average shade tolerance of saplings was lowest on the south edge. Temperature was greatest on the south edge and relative humidity was greatest in the interior. Percent soil moisture, nutrient concentrations, organic matter, and pH showed no significant trends. Our results suggest that light is the most important environmental factor in determining species composition, density, and size of saplings across edge-interior gradients. Our results also show that species compositional edge effects do not penetrate deeply into this mature forest fragment at present, but that they likely penetrated deeper in the forest when the edge was young and narrowed as the edge matured.
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