bluuebunny/crossref_metadata_2025_split huggingface dataset:
Population Viability, Nature Reserves, and the Outlook for Gray Wolf Conservation in North America
Authors: Fritts Steven H. , Carbyn Ludwig N. 
Published: April 2006

AbstractTheoretical work on population viability and extinction probabilities, empirical data from Canis lupus (gray wolf) populations, and expert opinion provide only general and conflicting conclusions about the number of wolves and the size of areas needed for conservation of wolf populations. There is no threshold population size or proven reserve design that guarantees long‐term (century or more) survival for a gray wolf population. Most theoretical analyses of population viability have assumed a single, isolated population and lack of management intervention, neither of which is likely for wolves. Data on survival of actual wolf populations suggest greater resiliency than is indicated by theory. In our view, the previous theoretical treatments of population viability have not been appropriate to wolves, have contributed little to their conservation, and have created unnecessary dilemmas for wolf recovery programs by overstating the required population size. Nonetheless, viability as commonly understood may be problematic for small populations at the fringe of or outside the contiguous species range, unless they are part of a metapopulation. The capability of existing nature reserves to support viable wolf populations appears related to a variety of in situ circumstances, including size, shape and topography of the reserve; productivity, numbers, dispersion, and seasonal movement of prey; extent of poaching inside; degree of persecution outside; exposure to enzootica; attitudes of local people; and proximity to other wolf populations. We estimate that a population of 100 or more wolves and a reserve of several thousand square kilometers may be necessary to maintain a viable population in complete isolation, although 3000 km2 or even 500–1000 km2 may be adequate under favorable circumstances. In most cases, management intervention is probably necessary to assure the viability of relatively small, isolated populations. Because most reserves may be inadequate by themselves to ensure the long‐term survival of wolf populations, favorable human attitudes toward the species and its management must be recognized as paramount, and cooperation of neighboring management jurisdictions will be increasingly important.
The Establishment and Maintenance of a Species‐Rich Grassland on a Reclaimed Opencast Coal Site
Authors: Chapman R. , Younger A. 
Published: April 2006

AbstractWe conducted an experiment with the dual aims of (1) examining the feasibility of establishing a species‐rich grassland using a commercially available grass and wild‐flower seed mixture and (2) examining the effects of different defoliation and fertilizer managements on the productivity, species richness, diversity, and composition of a species‐rich grassland established on a site reclaimed after opencast coal mining. The use of the seed mixture successfully established a sward of some 18–25 species per square meter. The species composition was enriched to some extent by recruitment of unsown species, principally from the soil seed bank. Hay‐type defoliation management produced greater dry matter yield and species richness than grazing defoliation, but grazing defoliation produced greater species diversity. Fertilizer application had no significant effect on dry matter production but reduced species diversity. Ordination analysis revealed that both defoliation and fertilizer management significantly affected species composition. The response obtained by individual species was explicable largely by their comparative biology.
Nectar Resources and Their Influence on Butterfly Communities on Reclaimed Coal Surface Mines
Authors: Holl Karen D. 
Published: April 2006

AbstractDespite the critical role insects play in ecosystem functioning, there has been little study of factors affecting their reestablishment in restored ecosystems. The goals of this research were to quantify the nectar resources provided by reclaimed coal surface mines and to examine the role nectar resources play in determining butterfly community composition on these sites. Adult butterfly communities and nectar resources were sampled on 18 reclaimed coal surface‐mined sites and five unmined hardwood sites in southwestern Virginia. Recently, reclaimed sites provided an average of 300 times the nectar abundance of the surrounding hardwoods, and nectar abundance and species richness decreased with time since reclamation. Total nectar abundance was highly correlated with total butterfly abundance and species richness for the entire flight season; these variables were also significantly correlated among sites during most of the 12 sampling periods during the flight season. In only a few cases, however, were butterfly and nectar abundance and species richness significantly correlated within individual sites during the flight season. These results suggest that, although adults of many butterfly species move in response to nectar availability, nectar resources are not sufficiently limiting that their life histories have evolved to maximize nectar resources temporally. While planting species in restored areas that provide abundant nectar will likely attract adult butterflies, this is only one of a number of habitat variables that must be considered in efforts to restore butterfly populations. Finally, adult butterflies appear to have limited utility as indicators of revegetation success.
Effects of Beach Nourishment on Sea Turtles: Review and Research Initiatives
Authors: Grain D. Andrew , Bolten Alan B. , Bjorndal Karen A. 
Published: April 2006

AbstractBeach nourishment is an engineering solution to erosion of beaches. As in any restoration project, the goals of beach nourishment are the restoration of habitat to promote survival of plants and animals and to maintain aesthetically pleasing sites for humans. Unfortunately, beach nourishment sometimes alters parameters of the natural beach, decreasing the reproductive success of sea turtles. Engineers have recognized this problem and are working to improve nourishment practices. Biologists must specify problems incurred by sea turtles as a result of beach nourishment so that they may be addressed. A review of the literature on sea turtles and beach nourishment found certain problems repeatedly identified. For nesting females, characteristics induced by nourishment can cause (1) beach compaction, which can decrease nesting success, alter nest‐chamber geometry, and alter nest concealment, and (2) escarpments, which can block turtles from reaching nesting areas. For eggs and hatchlings, nourishment can decrease survivorship and affect development by altering beach characteristics such as sand compaction, gaseous environment, hydric environment, contaminant levels, nutrient availability, and thermal environment. Also, nests can be covered with excess sand if nourishment is implemented in areas with incubating eggs. The extent and implication of each problem are discussed, and future research initiatives are proposed.
Five Elements for Effective Evaluation of Stream Restoration
Authors: Kondolf G. Mathias 
Published: April 2006

AbstractRiver and stream restoration projects are increasingly numerous but rarely subjected to systematic post‐project evaluation. The few such evaluation studies conducted have indicated a high percentage of failures. Thus, post‐project evaluation (and dissemination of results) is essential if the field of river restoration is to advance. Effective evaluation of project success should include: (1) Clear objectives, essential to identity potential incompatibilities among project objectives and to provide a framework for design of project evaluation. (2) Baseline data, needed as an objective basis for evaluating change caused by the project and encompassing as long a pre‐project period as possible (including a detailed historical study). (3) Good study design, to demonstrate the effects of restoration projects in the complex riverine environment. (4) Commitment to the long term, to detect effects evident only years following project completion; in general, monitoring should continue for at least a decade, with surveys conducted after each flood above a predetermined threshold. (5) Willingness to acknowledge failures, or rather to recognize that each restoration project constitutes an experiment, so that a failure can be just as valuable to the science as a success, provided we can learn from it (which requires objective, robust post‐project evaluation).
Releasing Rain Forest Succession: A Case Study in the Dicranopteris linearis Fernlands of Sri Lanka
Authors: Cohen Andrew L. , Singhakumara B.M.P. , Ashton P. Mark S. 
Published: April 2006

AbstractThroughout tropical moist climates, Dicranopteris linearis fernlands can develop as a result of rain forest clearance followed by frequent burning. In Sri Lanka, D. linearis fern‐lands are capable of suppressing the regeneration of rain forest. Field experiments were conducted at Sinharaja Man and Biosphere Reserve, a rain forest where fernlands occupy substantial areas of the reserve boundary. The experiment's objective was to identify methods for initiating forest regeneration in fernlands dominated by D. linearis Three disturbance treatments were used to initiate seedling regeneration: clean weed, root removal, and till. We hypothesized that increasing the severity of the soil disturbance would establish vegetation with higher species richness and diversity, greater above‐ground dry biomass, and higher percentage cover and seedling density. Results indicate only partial support for this hypothesis. Dry biomass was greatest in till treatments, the most severe soil disturbance. By comparison, species richness and diversity, seedling density, and percentage cover were greatest in root‐removal treatments, though in many instances the differences were not significant. The study clearly demonstrated that any kind of soil disturbance can facilitate the establishment of herbs, shrubs, and trees in a fernland dominated by D. linearis. Results showed that herbs, sedges, grasses, and pioneer shrubs represented greater proportions of seedling recruits than did pioneer trees. Seedlings of primary‐forest tree species were nearly nonexistent. In general, results showed that soil disturbance can play an important role in site preparation for the purpose of initiating non‐fern vegetation in fernlands dominated by D. linearis.
The Need for Consideration of Fire Behavior and Effects in Prescribed Burning
Authors: Johnson E. A. , Miyanishi K. 
Published: April 2006

AbstractPrescribed burns are increasingly being used in ecological restoration and vegetation management. Despite the accumulation of scientific information on fire behavior and fire effects, however, in many cases fires are prescribed without consideration of such information and often simply because of evidence of past fires. Rather than basing fire management plans on ideas of the historical “natural” occurrence of fire, we present the case for fire management being based on the fire effects desired. Effective fire management and development of proper fire prescriptions require an understanding of fire processes and heat transfer that explain fire behavior characteristics, as well as an understanding of how fire behavior is coupled to specific fire effects. We provide a basic introduction to these concepts and processes, which will help in understanding the importance of having a more technical understanding of fire. The discussion includes the processes of heat transfer and the relative role of various fuel variables in these processes, as well as the concepts of fire intensity, rate of spread, fuel consumption, duff consumption, fire frequency, and the ecological effects associated with variation in these characteristics of fire behavior.
Evaluation of Wetland Gain and Loss of Abandoned Agricultural Impoundments in South Louisiana, 1978–1988
Authors: Trepagnier C. M. , Kogas M. A. , Turner R. E. 
Published: April 2006

AbstractAt least 43 agriculture fields were built in south Louisiana wetlands between 1900 and 1920 using pumps and levees. All but one project is now abandoned as a result of soil subsidence, financial difficulties, or multiple levee failures. Some are now in flood‐protected urban zones, and the remainder are mostly open water. The total area of abandoned agricultural fields in 1990 is large (> 80,000 ha), and their levees continue to deteriorate naturally. Ten failed or abandoned coastal agricultural impoundments (22,680 ha) were examined to determine recent wetland restoration or regression rates from 1978 to 1988. Wetland area and levee length were determined from aerial photography for 1978,1983,1985, and 1988. Average wetland change rates for all areas ranged from −4.28 to +2.54% per year from 1978 to 1988. One site gained wetland area between 1978 and 1988 (77 ha/yr), and four sites gained wetland area between 1985 and 1988 (range 14–439 ha/yr). Wetland area in the other sites either remained stable or declined during the study period. The results from a multiple regression model indicate that restoration is inversely related to impoundment size and directly related to levee reduction. Results from a multiple regression model indicate that active levee removal will probably enhance wetland restoration rates at a very favorable cost (< $1/ha) and will be sustainable with little additional management.
An Historical Perspective on the Kissimmee River Restoration Project
Authors: Koebel Joseph W. 
Published: April 2006

AbstractThis paper reviews the events leading to the channelization of the Kissimmee River, the physical, hydrologic, and biological effects of channelization, and the restoration movement. Between 1962 and 1971, in order to provide flood control for central and southern Florida, the 166 km‐long meandering Kissimmee River was transformed into a 90 km‐long, 10 meter‐deep, 100 meter‐wide canal. Channelization and transformation of the Kissimmee River system into a series of impoundments resulted in the loss of 12,000–14,000 ha of wetland habitat, eliminated historic water level fluctuations, and greatly modified flow characteristics. As a result, the biological communities of the river and floodplain system (vegetation, invertebrate, fish, wading bird, and waterfowl) were severely damaged. Following completion of the canal, the U.S. Geological Survey released a report documenting the environmental concerns associated with channelization of the river. This action led to the 1971 Governor's Conference on Water Management in South Florida that produced a consensus to request that steps be taken to restore the fish and wildlife resources and habitat of the Kissimmee basin. In 1976, the Florida Legislature passed the Kissimmee River Restoration Act. As a result, three major restoration and planning studies (first federal feasibility study [1978–1985], the Pool B Demonstration Project [1984–1990], and the second federal feasibility study [1990‐present] were initiated (1) to evaluate measures and provide recommendations for restoring flood‐plain wetlands and improving water quality within the Kissimmee basin, (2) to assess the feasibility of the recommended dechannelization plan, and (3) to evaluate implementation of the dechannelization plan. The recommended plan calls for the backfilling of over 35 km of C‐38, recarving of 14 km of river channel, and removal of two water‐control structures and associated levees. Restoration of the Kissimmee River ecosystem will result in the reestablishment of 104 km2 of river‐floodplain ecosystem, including 70 km of river channel and 11,000 ha of wetland habitat, which is expected to benefit over 320 species of fish and wildlife.
Conceptual Evaluation of Factors Potentially Affecting Restoration of Habitat Structure within the Channelized Kissimmee River Ecosystem
Authors: Toth Louis A. , Arrington D. Albarey , Brady Mark A. , Muszick Dera A. 
Published: April 2006

AbstractA critical element of the ongoing effort to restore the ecological integrity of Florida's Kissimmee River ecosystem is the reestablishment of pre‐channelization habitat structure and function. Restoration of habitat will form the basis for responses by most biological components of the ecosystem and will provide a key indicator of the success of the restoration effort. This paper evaluates the relative importance of a range of abiotic and biotic habitat parameters in the existing and historic Kissimmee River ecosystem and provides a conceptual framework for predicting expected spatial and temporal responses of river and floodplain habitats to the restoration project. Among the ecological factors and process that influenced the development, dynamics, and maintenance of river and floodplain habitat structure, hydrology is expected to be of central importance in eliciting restoration responses in the Kissimmee River Ecosystem. Based on the assumption that the restoration plan will reestablish historic hydrologic characteristics, predictions are made of expected responses by geomorphic and vegetative components of the Kissimmee River's habitat structure. Recommendations are made regarding key habitat parameters requiring long term tracking and analysis and utilization of a geographic information system(GIS). A hierarchical habitat classification scheme is provided as a foundation for all components of the restoration evaluation program.
Restoration of the Kissimmee River: A Conceptual Model of Past and Present Fish Communities and Its Consequences for Evaluating Restoration Success
Authors: Trexler Joel C. 
Published: April 2006

AbstractEfforts to restore fish communities of the Kissimmee River will require carefully defined criteria for assessing success. A goal of regaining communities mirroring those in the historical river may not be an appropriate target because the ecological conditions of the river before channelization are poorly known. The Kissimmee River is in a biogeographic region historically low in fish diversity, and no comparable rivers in that region remain substantially unaltered by human activity to permit their use as reference sites indicative of conditions in the Kissimmee before channelization. I propose alternative criteria for assessing restoration success emphasizing expectations for ecosystem function in similar floodplain rivers. Assessing ecosystem function will be less simple than assessing criteria such as fish condition or density of selected species. But criteria based solely on fish‐population characteristics cannot be justified quantitatively. Information integrated from several levels of biotic organization (individuals, populations, communities, and systems) should be drawn upon in making conclusions about restoration success. I develop a conceptual model to outline aspects of ecosystem function that could serve as a basis for evaluation of the restoration of fish communities of the Kissimmee River. The model focuses on the dynamics of the flux of floodplain‐channel nutrients and the movement of larvae, juvenile, and adult fishes and macroinvertebrates. The present community may be dominated more by species tolerant of low‐oxygen conditions, such as gar and bowfin, than the restored community will be. I propose that nest sites may be the limiting recruitment success of substrate spawning species in the channelized river and that these species, including sunfish and large‐mouth bass, will increase in abundance after restoration. Also, species relying on floodplain habitats, including sun‐fish species, darters, and some minnows, may also increase in frequency with restoration of floodplain‐channel hydro‐logical conditions and habitats. The observation that no species are known to have disappeared from the Kissimmee River, and its relatively simple community structure compared to rivers of comparable size elsewhere, are encouraging for prospects of successful restoration.
Use of Two Waterbird Guilds as Evaluation Tools for the Kissimmee River Restoration
Authors: Weller Milton W. 
Published: April 2006

AbstractTwo groups of waterbirds have been chosen to assist in measuring the success of restoration of the traditional channel configuration, hydrologic regimes, and floodplain wetlands of the Kissimmee River: waterfowl (Anseriformes) and waders (Ciconiiformes). Waterfowl are dominant, swimming omnivores that use seeds, foliage, and invertebrates; waders are mainly walking predators that eat fish of various sizes. Both can be censused by well‐established air and ground techniques, and both can be used to compare post‐restoration with channelized or pre‐channelization population data (waterfowl) or bird use of channelized versus restored wetlands (waders). In addition to use of population data, species richness and regularity of occurrence should provide a basis for assessing restoration of biological integrity. Conceptual models of avian habitat use for nesting and feeding demonstrate patterns of segregation that will aid assessments for some species. Other species show high overlap in foods and habitats and will require additional measures of response. To understand these patterns and reasons underlying waterbird use, measurements of habitat type, vegetation structure, and food resources will be essential. Integration of these high trophic‐level guilds with evaluations of other system components will ensure an ecosystem perspective. Predicted responses to restoration suggest an increase in species richness and number of individuals of many species.
Genetic Structure and Gene Flow in Elymus glaucus (blue wildrye): Implications for Native Grassland Restoration
Authors: Knapp Eric E. , Rice Kevin J. 
Published: April 2006

AbstractInterest in using native grass species for restoration is increasing, yet little is known about the ecology and genetics of native grass populations or the spatial scales over which seed can be transferred and successfully grown. The purpose of this study was to investigate the genetic structure within and among populations of Elymus glaucus in order to make some preliminary recommendations for the transfer and use of this species in revegetation and restoration projects. Twenty populations from California, Oregon, and Washington were analyzed for allozyme genotype at 20 loci, and patterns of variation within and among populations were determined. Allozyme variation at the species level was high, with 80% of the loci polymorphic and an average expected heterozygosity (an index of genetic diversity) of 0.194. All but two of the populations showed some level of polymorphism. A high degree of population differentiation was found, with 54.9% of the variation at allozyme loci partitioned among populations (Fst= 0.549). A lesser degree of genetic differentiation among closely spaced subpopulations within one of the populations was also demonstrated (Fst= 0.124). Self‐pollination and the patchy natural distribution of the species both likely contribute to the low level of gene flow (Nm= 0.205) that was estimated. Zones developed for the transfer of seed of commercial conifer species may be inappropriate for transfer of E. glaucus germplasm because conifer species are characterized by high levels of gene flow. Limited gene flow in E. glaucus can facilitate the divergence of populations over relatively small spatial scales. This genetic differentiation can be due to random genetic drift, localized selective pressures, or both. In order to minimize the chances of planting poorly adapted germplasm, seed of E. glaucus may need to be collected in close proximity to the proposed restoration site.