Figure 1 - uploaded by James Herkert
Content may be subject to copyright.
Forest Fragmentation...
Similar publications
The springtails of the Netherlands: genus Orchesella (Hexapoda: Entognatha: Collembola) This is the first in a series of publications on the identification, distribution and ecology of springtails of the Netherlands. In this paper the genus Orchesella Templeton, 1835 is described, which is with four native species present in the Netherlands, i.e. O...
Status and ecology of Bengal Florican in Uttar Pradesh, India
MOUSETAIL IN THE NORTHERN AND CENTRAL PARTS OF THE PROVINCE OF LIMBURG
Mousetail (Myosurus minimus) is a small plant of open, moist habitats on sandy or loamy substrates, flowering in spring (March-April). This article documents the distribution
of Mousetail in the northern and central parts of the Province of Limburg. In these areas, Mousetail gr...
Studies at large spatial scales have a long history in taphonomic research, since they contribute to understand both diversity and regularity that characterize processes with respect to the conditions prevailing at different environmental contexts. Thus, results of these studies can serve both as the basis to analyze zooarchaeological assemblages i...
Citations
... pollution from urban matrix surroundings, severe and frequent disturbances by humans) (Faeth et al. 2011;Saunders et al. 1991) and urbanization may represent detrimental influences (i.e. population decline of some species or deflation of the ecological value of forests patches) even when forest patches are maintained (Engels and Sexton 1994;Herkert 1993). ...
A significant decline in biodiversity is associated with the current and upcoming degree of urbanization. A challenging strategy to address this conflict is to make urban growth compatible with biodiversity protection and in this context urban parks can play a crucial role. Urban systems are highly dynamic and complex human-shaped ecosystems, where the relationship between species and environment may be altered and make the preservation of biodiversity within them a challenging goal. In this study, we analysed how different environmental features affect bird biodiversity in one of the most urbanized areas of Italy (the metropolitan area of Milan) at different spatial scales. Bird surveys were conducted in fifteen urban and peri-urban parks and environmental variables at landscape and local scale recorded. Results showed that a mixture of land covers and the presence of water bodies inside urban parks favoured species occurrence and abundance at landscape scale, but a surrounding dense urban matrix deflated biodiversity. At local scale, woodland cover and presence of water bodies were key determinants in ensuring overall high biodiversity but local-specific vegetation management produced an unusual pattern for forests species. In particular, the maintenance of large trees may not result in biodiversity support for forest bird species if large trees are not located in woodland areas with a significant tree density. To understand biodiversity patterns and provide useful information for urban planning and design, we need to provide insights into species/environment relationships at multiple scales in the urban environment.
... Grassland management suggestions by Kirby (1992) and Bignal & McCracken (1996) are based on the conservation outcomes of a wide array of research, and should help maintain overall prairie biodiversity; my results are consistent with their ideas. Prairie management guides by Herkert et al. (1993) and Hamilton (1994) provide numerous suggestions beneficial to grassland birds; both guides recommend that a variety of treatments be employed to generate a diversity of effect. Herkert et al. (1993) recommend a 3-5 year burning rotation for prairie preserves, but my results suggest less fire should be used. ...
... Prairie management guides by Herkert et al. (1993) and Hamilton (1994) provide numerous suggestions beneficial to grassland birds; both guides recommend that a variety of treatments be employed to generate a diversity of effect. Herkert et al. (1993) recommend a 3-5 year burning rotation for prairie preserves, but my results suggest less fire should be used. Hamilton's (1994) recommendation to use periodic haying and/or grazing to extend fire return intervals to >10 years is consistent with this study's recommendation to reduce fire usage. ...
1. During 1993 96 three tallgrass prairie songbirds experiencing long term declines were surveyed at 52 tallgrass prairies in Illinois, Iowa, Minnesota, North Dakota, and Wisconsin (USA) to study which management techniques maintained larger populations.
2. Sixteen factors influencing transect rates of Henslow's Sparrows Ammodramus henslowii, Grasshopper Sparrows A. savannarum, and Dickcissels Spiza americana were analyzed using stepwise regression and ANOVA.
3. Dickcissels and Grasshopper Sparrows strongly covaried in abundance. Both preferred larger sites but shared few other habitat preferences. Henslow's Sparrow was found at only one site and did not covary with the other species.
4. Henslow's Sparrows and Dickcissels preferred prairies with diverse vegetation. Grasshopper Sparrows and Dickcissels had significantly higher rates in larger prairies. Prairie diversity and patch size probably work together to create this area effect.
5. Although burning on a 1 6 year rotation is the standard prairie preserve management, all three species preferred longer periods since fire. Intensively dairy grazed units had low rates of all three birds. Henslow's Sparrows occurred only in idle habitat. Grasshopper Sparrows preferred light agricultural usage (rotational grazing or mowing/haying). Dickcissels preferred rotationally grazed sites and avoided burned sites.
6. Biennial to triennial haying after July 15, and rotational grazing, are recommended as the primary northern tallgrass prairie management practices for conserving Grasshopper Sparrows and Dickcissels. Because Henslow's Sparrow is by far the rarest of these birds, dense vegetation should be maintained for it using these treatments and some land should be idled for even longer periods at its few remaining Upper Midwest sites.
... For example, the size requirement of core areas in forested landscapes might be around 4000 ha, reflecting the forested condition of the landscape and the presence of wide-ranging species like bears. In contrast, core areas in human-dominated regions might be around 100 ha, targeting the needs of warblers or other birds (Bushman and Therres, 1988;Herkert et al., 1993;Robbins et al., 1989). Core areas in urban areas might focus primarily on water quality and stream stabilization, or any patch of woods large enough to provide interior conditions. ...
With the rising costs of fossil fuels and recognition of their environmental and human health impacts, wind energy projects have expanded throughout the world. Under the U.S. Endangered Species Act, wind developers must avoid, minimize, and mitigate impacts to listed species. With assistance from the Conservation Fund, the U.S. Fish and Wildlife Service sought to address potential wind energy impacts in the Midwest USA. To provide ecosystem and landscape contexts for mitigation, we identified key habitat (“core areas”) important to the full suite of native species and ecosystems, and corridors that would allow species dispersal, migration, recolonization, genetic exchange, and climate change adaptation. We identified core areas based on landscape types, focal/surrogate species requirements, and ecoregional differences. Corridors depend on both the composition and spatial arrangement of the landscape, and the movement abilities and landscape preferences of target organisms. We created a Terrestrial Movement Analysis tool to model connectivity for four different ecotypes, each with their own core areas and movement permeabilities. The tool generated random sets of starting locations (each location corresponding to an individual organism) and calculated optimal paths to all other habitat within the organism's dispersal range. This process was executed iteratively; then it summed the random iterations to derive overall landscape connectivity, showing pathway usage, the cost of moving through a corridor (broader than single paths), and overall landscape movement potential. The resulting data can be used for multiple applications.
... Reductions in grassland and wetland area have decreased habitat availability for grassland birds, waterfowl and shorebirds . Grassland birds have experienced greater, faster and more widespread declines than any other ecological guild on the North American continent (Herkert et al. 1993;. Migratory waterfowl and shorebirds have also exhibited negative responses to reductions in grassland and wetland area . ...
... Grassland birds have been negatively impacted by reductions and fragmentation of native grasslands over the past two centuries White et al. 2000;Grant et al. 2004). Grassland birds have experienced greater, faster and more widespread declines than any other ecological guild on the North American continent (Herkert et al. 1993;. Remnant and restored grasslands provide grassland birds with crucial feeding and breeding habitat (Johnson & Schwartz 1993;Johnson & Igl 1995;; therefore, effective grassland conservation, restoration and management are paramount to reversing grassland bird population declines. ...
... Grassland birds have been negatively impacted by reductions and fragmentation of native grasslands over the past two centuries White et al. 2000;Grant et al. 2004). Grassland birds have experienced greater, faster and more widespread declines than any other ecological guild on the North American continent (Herkert et al. 1993;. Today, remnant and restored grasslands provide grassland birds with crucial feeding and breeding habitat (Johnson & Schwartz 1993;Johnson & Igl 1995;. ...
Agriculture is an economically important form of landuse in the North American Great Plains. Since 19th Century European settlement, conversion of grasslands to rowcrops has increased food and bioenergy production, but has decreased wildlife habitat. Future agricultural landuse changes may be driven by alternative energy demands and regional climatic changes. Landuse change and its drivers could affect bioenergy production, wildlife populations and natural resources, and considering the potential impacts of impending changes in advance could assist with preparations for an uncertain future.
This study addressed how the conversion of marginally productive agricultural lands in the Rainwater Basin region of south–central Nebraska, U.S.A. to bioenergy switchgrass (Panicum virgatum) might impact ethanol production, grassland bird populations and agricultural groundwater withdrawals. This study also used multi–model inference to develop predictive models explaining annual variation in springtime wetland occurrence and flooded area in the Rainwater Basin.
Results suggest that producing adequate biomass for year round cellulosic ethanol production from switchgrass and residual maize (Zea mays) stover within existing starch–based ethanol plant service areas is feasible at current feedstock yields, removal rates and bioconversion efficiencies. Throughout the Rainwater Basin, the replacement of marginally productive rowcrop fields with switchgrass could increase ethanol production, conserve groundwater and benefit grassland birds under novel future climatic conditions. However, converting Conservation Reserve Program (CRP) grassland to switchgrass could be detrimental to grassland bird populations. Predictive wetland inundation models suggest that springtime wetland inundation in the Rainwater Basin is a complex process driven by individual wetland characteristics, surrounding landuse and local weather events. The impacts of future climatic and landuse changes in the Rainwater Basin and surrounding Great Plains is ultimately likely to depend on which forms of alternative landuse are adopted and on how intensely change occurs.
Advisor: Craig R. Allen
... A forest block with 100 ha of mature interior deciduous or mixed forest should provide minimum habitat for 15 of the 18 forest birds found in the study area (Bushman and Therres, 1988). Robbins et al. (1989), Herkert et al. (1993), andRoswell (2004) also support a 100 ha minimum forest area. ...
Federal, state, and local governments construct thousands of kilometers of roads each year in the U.S.A., as well as undertaking widening, rerouting or repair projects. Under the National Environmental Policy Act (NEPA), environmental impacts from such construction must be offset by mitigation measures (e.g., stream or wetland restoration). Unfortunately, restoration projects often are opportunistic, do not consider a broad landscape context, and have a low benefit–cost ratio. In 2007, the Maryland State Highway Administration asked The Conservation Fund, the Maryland Department of Natural Resources, and the U.S. Fish and Wildlife Service to help identify and evaluate natural resource stewardship opportunities in four Maryland watersheds that could potentially be affected by construction of a highway bypass. Stewardship activities, including conservation, restoration, or management of natural resources, would go above and beyond required mitigation. After soliciting feedback from stakeholders and reviewing pertinent literature, we modeled and validated a conservation network of high-quality wildlife and plant habitat (core areas), large contiguous natural areas (hubs), and linkages to facilitate wildlife movement and gene flow (corridors). We then ranked elements of this network at multiple scales, and identified high priority areas for conservation and restoration. Finally, we developed and tested protocols for field assessment and benefit–cost optimization. We hope that this approach can be adapted and improved by highway agencies and other entities for environmental planning and protection, and have a report available upon request with full details.
... By burning adjacent management units in alternate years, insect species from unburned units may be able to recolonize burned areas (Panzer et al. 1995). Avian species diversity is also thought to be enhanced by managing large areas as a mosaic of burned and unburned patches (Herkert et al. 1993). Because fire is a landscape-scale natural process, burn plans for small wet prairie remnants should include, wherever possible, adjacent fire-dependent upland (e.g., oak barrens, drymesic southern forest) and lowland (e.g., prairie fen, southern wet meadow) systems. ...
Overview: Wet prairie is native wetland grassland that occurs on frequently saturated, occasionally inundated soils on outwash plains and outwash channels and in depressions on ground moraines, end moraines, and ice-contact features. Soils range from loam to loamy sands and sandy clays, typically with neutral pH and high organic content. Cordgrass (Spartina pectinata) and bluejoint grass (Calamagrostis canadensis) are the dominant or subdominant grasses, often associated with several sedges (Carex spp.). Fluctuating water levels and fire are important natural disturbances.
... By burning adjacent management units in alternate years, insect species from unburned units may be able to recolonize burned areas (Panzer et al. 1995). Avian species diversity is also thought to be enhanced by managing large areas as a mosaic of burned and unburned patches (Herkert et al. 1993). Because fire is a landscape-scale natural process, burn plans for small wet prairie remnants should include, wherever possible, adjacent fire-dependent upland (e.g., oak barrens, drymesic southern forest) and lowland (e.g., prairie fen, southern wet meadow) systems. ...
Overview: Wet prairie is native wetland grassland that occurs on frequently saturated, occasionally inundated soils on outwash plains and outwash channels and in depressions on ground moraines, end moraines, and ice-contact features. Soils range from loam to loamy sands and sandy clays, typically with neutral pH and high organic content. Cordgrass (Spartina pectinata) and bluejoint grass (Calamagrostis canadensis) are the dominant or subdominant grasses, often associated with several sedges (Carex spp.). Fluctuating water levels and fire are important natural disturbances. Global and State Rank: G3/S2 Range: Wet prairie is broadly distributed throughout the central Midwestern United States and adjacent Canadian provinces, occurring in Montana, and Ohio (NatureServe 2009). Species composition and dominance patterns vary throughout this range. In Michigan, wet prairie occurs south of the climatic tension zone in the southern Lower Peninsula, where it was likely prevalent historically in subsection VI.2 (Kalamazoo Interlobate), and infrequent in subsections VI.1 (Washtenaw), VI.3 (Allegan), and VI.4 (Ionia) (Albert et al. 2008). Currently, high quality occurrences of wet prairie have been documented from all four subsections within which it was historically distributed (MNFI 2010). Wet prairie on the glacial lakeplain is classified as lakeplain wet prairie (Albert and Kost 1998a, Kost et al. 2007).
... By burning adjacent management units in alternate years, insect species from unburned units may be able to recolonize burned areas (Panzer et al. 1995). Avian species diversity is also thought to be enhanced by managing large areas as a mosaic of burned and unburned patches (Herkert et al. 1993). Because fire is a landscape-scale natural process, burn plans for small wet-mesic prairie remnants should include, wherever possible, adjacent fire-dependent upland (e.g., oak barrens, dry-mesic southern forest) and lowland (e.g., prairie fen, southern wet meadow) systems. ...
Overview: Wet-mesic prairie is a native wetland grassland that occurs on occasionally saturated, rarely inundated soils on outwash plains and outwash channels and in depressions on ground moraines, end moraines, and ice-contact features. Soils range from loam to loamy sands and sandy clays, typically with neutral pH and high organic content. Dominant or subdominant species include big bluestem (Andropogon gerardii), Indian grass (Sorghastrum nutans), cordgrass (Spartina pectinata), bluejoint grass (Calamagrostis canadensis), and sedges (Carex spp.). Fluctuating water levels and fire are important natural disturbances.
... Four of the 15 preserves surveyed have had an addition of adjacent habitat ( Two bird species that were found in the prairie preserves were not considered grassland bird species but are still area sensitive (Herkert et al. 1993 The four smallest preserves had as many as four area-sensitive species and as many as three area-sensitive grassland species. Among the six largest preserves, the number of areasensitive species varied greatly, with some preserves having no more than the smallest preserves. ...
... Therefore, it is important to recognize that other patch variables such as habitat diversity might be correlated to patch area and perimeter-to-area ratio, since habitat diversity might increase with increased size of the preserves. (Herkert et al. 1993). These species, along with many other grassland birds found in the preserves, have specific microenvironment requirements. ...
This study looks at the effects of patch and landscape characteristics on area-sensitivity of grassland bird species. We investigate the effect of area and perimeter-to-area ratio on grassland bird species found in the Iowa State Preserves, with a specific focus on area-sensitive bird species. We selected prairie preserves or preserves with a prairie component for inventory. Both area and perimeter-to-area ratio were good predictors for bird species found in the preserves. Perimeter-to-area ratio was a better predictor than area for area-sensitive grassland bird species. The other major aspect of my research addressed the possible effect of landscape factors on habitat use by area-sensitive grassland birds in southern Iowa. We selected six focal grassland bird species. Three of them responded to landscape variables. Dickcissel and Eastern Meadowlark responded to the amount of woodland in the landscape. Bobolink responded to amount of grassland in the landscape. Grasshopper Sparrow, Henslow's Sparrow and Bobolink did not respond to any of our landscape variables. Both of our studies showed that when managing for area-sensitive species it is important to take into account and, if possible, combine both patch scale and landscape scale variables.
... In the eastern tallgrass prairie, some birds, such as the Killdeer and Upland Sand Piper require short vegetation across large areas. Other species, such as Eastern Meadow Lark and Bobolink, utilize medium height vegetation with moderate amounts of litter, whereas species such as Henslow's Sparrow and Marsh Wren occur where the vegetation is tall with heavy amounts of litter (Herkert et al. 1993). Endemic birds of western Great Plains also have characteristic distributions related to historic grassland types and grazing patterns (Knopf 1996). ...
Grasslands are a widespread vegetation type that once comprised 42% of the plant cover on earth's surface. Features commonly shared among grasslands are climates with periodic droughts, landscapes that are level to gently rolling, high abundances of grazing animals, and frequent fires. World-wide expansion of grasslands occurred 8 to 6 MaBP and was associated with increasing abundance of grasses using the C4 photosynthetic pathway, a decline in woodlands, and coevolution of mammals adapted to grazing and open habitats. Beginning with Transeau's seminal paper on the prairie peninsula in 1935, North American ecologists debated the relative importance of fire and climate in determining the distribution of grasslands. In the 1960's, a major research interest was the response of prairies to fire, especially the productivity of burned and unburned grasslands. Understanding mechanisms for increased productivity on burned prairies began in the late 1960's and continued into the middle 1980's. During the past 20 to 25 years, grassland research has focused on the coevolution of grasses and mammalian grazers and fire-grazing interactions that affect habitat heterogeneity and diversity across trophic levels. While this paper does not follow a chronological development of our understanding of grasslands, all of these major research interests are considered.
