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61.
Strange E Galbraith H Bickel S Mills D Beltman D Lipton J 《Environmental management》2002,29(2):290-300
The amount of ecological restoration required to mitigate or compensate for environmental injury or habitat loss is often
based on the goal of achieving ecological equivalence. However, few tools are available for estimating the extent of restoration
required to achieve habitat services equivalent to those that were lost. This paper describes habitat equivalency analysis
(HEA), a habitat-based “service-to-service” approach for determining the amount of restoration needed to compensate for natural
resource losses, and examines issues in its application in the case of salt marsh restoration. The scientific literature indicates
that although structural attributes such as vegetation may recover within a few years, there is often a significant lag in
the development of ecological processes such as nutrient cycling that are necessary for a fully functioning salt marsh. Moreover,
natural variation can make recovery trajectories difficult to define and predict for many habitat services. HEA is an excellent
tool for scaling restoration actions because it reflects this ecological variability and complexity. At the same time, practitioners
must recognize that conclusions about the amount of restoration needed to provide ecological services equivalent to those
that are lost will depend critically on the ecological data and assumptions that are used in the HEA calculation. 相似文献
62.
A new, higher dam was installed at Kerkini Reservoir in 1982, causing habitat and landscape disruption. A decrease in the
area of grassland and shallow water areas, the rapid disappearance of reedbeds, the appearance of beds ofNymphaea, and the disappearance of half the forest area were all observed between 1982 and 1991. With the new hydrological regime,
a lacustrine system was created, with an extensive, rather deep (4–8 m), pelagic zone favorable for the development of coarse
fish species throughout the year. After 1982, an increase in fishing effort and a change in the relative abundance of fish
species in the catch, including the disappearance of eels and wels, were observed. The impact of the rise in the water level
of breeding aquatic birds led to a general decline in species typical of marshy habitats in favor of species preferring deeper
open water habitats. A decrease was recorded in bird species that feed largely on invertebrates and to a lesser extent fish
(e.g., glossy ibis) and that require extensive shallow feeding areas. There was a decline in geese, whose nests were regularly
flooded, and a major increase in piscivorous birds, particularly diving birds (e.g., cormorants), which prefer deeper open
water and benefitted directly from the large increase in coarse fish biomass. The disappearance of birds breeding in flooded
meadows (e.g., black-winged stilts) and of those restricted to reedbeds (e.g., marsh harrier) occurred from 1983. Over the
same period, the changes in populations of wintering birds at Kerkini were different from those occurring in other wetlands
in northern Greece. The changes recorded in the populations of wintering birds at Kerkini did not therefore result from overall
regional trends but from the major habitat modifications that occurred to this wetland. As for breeding birds, strictly piscivorous
species increased greatly as a result of the increased availability of fish, but also due to the appearance of many suitable
night roosting sites (flooded trees) and to the great increase in the area of open water greater than 2 m deep. Today, Kerkini
has become the most important breeding site in Greece for a majority of colonial waterbirds. In contrast, wintering shorebirds
practically disappeared. The many changes recorded in the status of breeding and wintering birds at Kerkini can mostly be
explained by the changes that occurred in the functioning of the ecosystem and in the habitat structure following the inauguration
of the new hydrological regime. These changes did not all occur at the same time: some were immediate and others required
a delay before they could be detected. 相似文献
63.
The applicability of the Habitat Evaluation Procedure (HEP) was assessed for several nongame bird species in the central Adirondack Mountains of New York. Measures for 24 avian species and 33 associated habitat variables were collected during the summers of 1985 and 1986. The accuracy of four published Habitat Suitability Index (HSI) models was examined: pileated and downy woodpeckers, black-capped chickadee, and veery. Chickadee and veery models were judged successful and were then used to predict habitat quality for respective avian foragingguild members. The HSI model/guild approach provided poor predictors of habitat quality for ubiquitous and uncommon species. Information on relative abundance within the geographic region and specific cover types must be included when designing habitat evaluations using the guild approach. 相似文献
64.
We propose a biodiversity credit system for trading endangered species habitat designed to minimize and reverse the negative
effects of habitat loss and fragmentation, the leading cause of species endangerment in the United States. Given the increasing
demand for land, approaches that explicitly balance economic goals against conservation goals are required. The Endangered
Species Act balances these conflicts based on the cost to replace habitat. Conservation banking is a means to manage this
balance, and we argue for its use to mitigate the effects of habitat fragmentation. Mitigating the effects of land development
on biodiversity requires decisions that recognize regional ecological effects resulting from local economic decisions. We
propose Landscape Equivalency Analysis (LEA), a landscape-scale approach similar to HEA, as an accounting system to calculate
conservation banking credits so that habitat trades do not exacerbate regional ecological effects of local decisions. Credits
purchased by public agencies or NGOs for purposes other than mitigating a take create a net investment in natural capital
leading to habitat defragmentation. Credits calculated by LEA use metapopulation genetic theory to estimate sustainability
criteria against which all trades are judged. The approach is rooted in well-accepted ecological, evolutionary, and economic
theory, which helps compensate for the degree of uncertainty regarding the effects of habitat loss and fragmentation on endangered
species. LEA requires application of greater scientific rigor than typically applied to endangered species management on private
lands but provides an objective, conceptually sound basis for achieving the often conflicting goals of economic efficiency
and long-term ecological sustainability. 相似文献
65.
Associating Ecosystem Service Losses with Indicators of Toxicity in Habitat Equivalency Analysis 总被引:1,自引:0,他引:1
Habitat equivalency analysis (HEA) was developed as a tool to scale mitigation or restoration when habitat is contaminated by hazardous substances or has been otherwise harmed by anthropogenic activities. Applying HEA involves balancing reductions in habitat quality against gains from restoration actions, and quantifying changes in habitat quality in terms of ecological services. We propose a framework for developing ecological service definitions and measures that incorporate knowledge about the impacts of chemical contaminants on biota. We describe a general model for integrating multiple lines of evidence about the toxicity of hazardous substances to allow mapping of toxicological inputs to ecological service losses. We provide an example of how this framework might be used in a HEA that quantifies ecological services provided by estuarine sediments contaminated with polycyclic aromatic hydrocarbons. 相似文献
66.
We developed logistic regression models from data on biotic and abiotic variables for 172 sites on Banks Peninsula, New Zealand,
to predict the probability of occurrence of two diadromous fish, banded kokopu (Galaxias fasciatus) and koaro (G. brevipinnis). Banded kokopu occurrence was positively associated with small streams and low-intensity land uses (e.g., sheep grazing
or forested), whereas intensive land uses (e.g., mixed sheep and cattle farming) and lack of riparian forest cover impacted
negatively on occurrence at sampled sites. Also, if forests were positioned predominantly in lowland areas, banded kokopu
occurrence declined with increasing distance to stream mouth. Koaro occurrence was positively influenced by catchment forest
cover, high stream altitudes, and areas of no farming activity or mixed land uses. Intensive land uses, distance to stream
mouth, and presence of banded kokopu negatively influenced koaro occupancy of stream reaches. Banded kokopu and koaro presence
was predicted in 86.0% and 83.7% agreement, respectively, with field observations. We used the models to quantify the amount
of stream reaches that would be of good, moderate, and poor quality, based on the probability of occurrences of the fish being
greater than 0.75, between 0.75 and 0.5, or less than 0.5, respectively. Hindcasting using historical data on vegetation cover
undertaken for one catchment, Pigeon Bay, showed they would have occupied most of the waterway before anthropogenic modification.
We also modeled potential future scenarios to project potential fish distribution. 相似文献
67.
Traffic mortality and the role of minor roads 总被引:1,自引:0,他引:1
van Langevelde F van Dooremalen C Jaarsma CF 《Journal of environmental management》2009,90(1):660-667
Roads have large impacts on wildlife, as they form one of the principal causes of mortality, and disturbance and fragmentation of habitat. These impacts are mainly studied and mitigated on major roads. It is, however, a widespread misconception that most animals are killed on major roads. In this paper, we argue that minor roads have a larger impact on wildlife with respect to habitat destruction, noise load and traffic mortality. We use data on traffic related deaths in badgers (Meles meles) in The Netherlands to illustrate that traffic mortality is higher on minor roads. We ask for a more extensive investigation of the environmental impacts of minor roads. Moreover, we argue that the success of mitigation on roads drastically increases when both major and minor roads are integrated in the planning of traffic flows. Therefore, we propose a strategy based on the concept of a "traffic-calmed area". Traffic-calmed areas create opportunities for wildlife by decreasing limitations for animal movement. We ask for further studies to estimate what size traffic-calmed areas should be to maintain minimum viable animal populations. 相似文献
68.
Alexandridis TK Lazaridou E Tsirika A Zalidis GC 《Journal of environmental management》2009,90(7):2243-2251
The European Habitats Directive 92/43/EEC has defined the need for the conservation of habitats and species with the adoption of appropriate measures. Within the Natura 2000 ecological network of special areas of conservation, natural habitats will be monitored to ensure the maintenance or restoration of their composition, structure and extent. The European Space Agency's GlobWetland project has provided remotely sensed products for several Ramsar wetlands worldwide, such as detailed land cover-land use, water cycle and inundated vegetation maps. This paper presents the development and testing of an operational methodology for updating a wetland's habitat map using the GlobWetland products, and the evaluation of the extent to which GlobWetland products have contributed to the habitat map updating. The developed methodology incorporated both automated and analyst-supervised techniques to photo-interpret, delineate, refine, and evaluate the updated habitat polygons. The developed methodology was proven successful in its application to the wetland complex of the Axios-Loudias-Aliakmon delta (Greece). The resulting habitat map met the European and Greek national requirements. Results revealed that GlobWetland products were a valuable contribution, but source data (enhanced satellite images) were necessary to discriminate spectrally similar habitats. Finally, the developed methodology can be modified for original habitat mapping. 相似文献
69.
Rapid growth in marine sand mining for construction and other uses poses environmental challenges to coastal nations virtually
worldwide. Yet the development of management policies, such as a system of fees imposed on operators for damage caused by
mining, has been frustrated by a lack of studies to support such measures. Adapting a Beverton-Holt bioeconomic model, this
paper attempts to contribute to the estimation of external costs to commercial fisheries due to marine mining. Using the major
mining area of Ongjin in Korea as a case study, we estimate economic losses in use value of commercial fisheries through the
time to recovery of the injured resource stocks. Present value of lost catch over a 1-year period from mining to resource
recovery is estimated at $38,851 for a single “prototype” mining site. Estimated cumulative damages due to recurring mining
for 5 and 10 years are $1.5 million and $2.2 million, respectively, at 20 mining sites. Sensitivity analyses are used to examine
the effects of alternative assumptions to assess the many sources of uncertainty. Using a form of meta-analysis, dose-response
information is used to assess the excess mortality the mining sediment plume has on eggs and larvae and, ultimately, on the
value of lost catch ($841). Also addressed is the importance of specifying the appropriate “premining” conditions against
which to assess environmental losses at the mining site. Damages estimated with premining fish populations are $23,066 higher
than is the case using postmining conditions. Overall, the illustrative results suggest the variety of complex conditions
which influence damage to fisheries from mining and which can benefit from further study to improve management guidelines.
An erratum to this article can be found at 相似文献
70.
This study examines the impact of flooding on land of high conservation value located along part of the southern shoreline
of the River Clyde Estuary in western Scotland. This paper hypothesizes that, over the next 50 years, the frequency and extent
of coastal flooding will increase due to the gradual effect of global warming and the consequent rise in sea-level and increase
in storminess. It is argued that because of the great cost of constructing new flood defence systems it will not be possible
to protect all land areas to an equal extent from flooding. A means of ranking different land use will be necessary so that
society can make a rational judgement concerning which sections of coastline will be worth protecting. This study provides
a methodology that combines an objective ranking of conservation areas using non-economic indicators with a GIS model of flood
potential, and permits accurate forecasts of flood losses to conservation areas of different ecological value. The conservation
case study used in this paper proposes the use of an ecological weighting value based on five ecological variables each of
10 categories. Tables and maps identify the sites that have been highlighted as consisting of the most ‘valuable’ conservation
sites. The methodology makes extensive use of geographical information systems (GIS) to model the predicted areas of flooding
and to calculate conservation weighting values of the land areas. 相似文献