共查询到20条相似文献,搜索用时 15 毫秒
1.
The assessment of different policy options represents a major tool for decision-makers in Biosphere Reserves, to develop more-resilient strategies for sustainable development and to visualise unintended consequences of these policies.In this work we analyse eight measures proposed by different agents in order to meet the main objectives of environmental sustainability, included in the Action Plan of the Fuerteventura Biosphere Reserve (Spain). We quantified the effects of these measures in terms of the sustainability thresholds of 10 environmental indicators, also proposed by the Action Plan, which was integrated in the Fuerteventura Biosphere Reserve dynamic model. Their behaviours under these measures allow determination of whether the objectives will be met in the period 2012–2025. Although some indicators would improve under these measures, fitting certain objectives, some negative effects on other indicators confirm the existence of trade-offs among these objectives. For instance, grazing limitation would improve the proportion of high-quality vegetation but would negatively affect the Egyptian vulture population, which would even fall below its sustainability threshold. The definition of thresholds for each indicator allows decision-makers to establish a way to prioritise among the eight measures analysed. The results show that these measures are insufficient to meet the sustainability thresholds of four indicators (the landscape indicator, the proportion of renewable energy, the per capita primary energy consumption and carbon dioxide emissions). Focusing on the remaining six indicators and following the rule “Threshold out, measure out”, seven out of the eight measures would exceed some thresholds and should be avoided. Only one option, aimed at growing fodder to feed cattle on restored traditional agricultural lands, would not exceed any of these thresholds. However, this measure also presents certain negative effects regarding indicators related to flagship species (the houbara habitat and the Egyptian vulture population), which would require compensation measures. 相似文献
2.
Although many indicator-based sustainability monitoring tools for agriculture have been developed in the last decade, considerably less effort has been put on their validation. In the present study, we developed and applied a procedure to validate (i) MOTIFS (Monitoring Tool for Integrated Farm Sustainability), an indicator-based monitoring tool for integrated farm sustainability of Flemish dairy farms and (ii) a selection of ecological indicators (included in MOTIFS), related to nutrient use, energy use, water use and water quality. The procedure considers two steps. The first step is an accuracy evaluation, which consists of a design validation related to the scientific quality of MOTIFS and its selected indicators, and an output validation that is an evaluation of the information supplied by their output. For both validation types, we applied a transdisciplinary approach of stakeholder participation. The second step is a credibility evaluation, which relates to the degree of confidence potential end-users have in MOTIFS and hence their willingness to effectively use it in practice. This involves an end-use validation, for which we designed a test to evaluate (i) the end-use value of the selected indicators as decision aid tools, (ii) the end-use value of MOTIFS as a decision aid tool and communication tool and (iii) the willingness of potential end-users to use MOTIFS in practice. We considered two potential end-user groups: Flemish dairy farmers and ‘sustainability consultants’ (e.g. agricultural advisors assigned by farmer's organisations). Based on the validation results, we made suggestions to improve the tool and its effective application in practice. We concluded that MOTIFS is a potentially effective sustainability monitoring and management tool, since it has major assets that should be incorporated in any indicator-based system: positioning, informing, learning and communicating. 相似文献
3.
Hereditary disorders in Saguenay-Lac-St-Jean (Quebec, Canada) 总被引:2,自引:0,他引:2
M De Braekeleer 《Human heredity》1991,41(3):141-146
Saguenay-Lac-St-Jean is a geographically isolated region located in northeastern Quebec. Opened to the white settlement in 1938, its immigrants mainly came from Charlevoix, another isolated region of Quebec. The prevalence and/or incidence of several autosomal dominant and recessive disorders are very high. The overall birth prevalence of the recessive disorders was calculated at 1/207 living births and the overall carrier rate at 1/7 inhabitants. This situation may be explained by migration and social factors. 相似文献
4.
Locas A Barthe C Barbeau B Carrière A Payment P 《Canadian journal of microbiology》2007,53(6):688-694
A 1 year study was undertaken on groundwater that was a source of drinking water in the province of Quebec, Canada. Twelve municipal wells (raw water) were sampled monthly during a 1 year period, for a total of 160 samples. Using historic data, the 12 sites were categorized into 3 groups: group A (no known contamination), group B (sporadically contaminated by total coliforms), and group C (historic and continuous contamination by total coliforms and (or) fecal coliforms). Bacterial indicators (total coliform, Escherichia coli, enteroccoci), viral indicators (somatic and male-specific coliphages), total culturable human enteric viruses, and noroviruses were analyzed at every sampling site. Total coliforms were the best indicator of microbial degradation, and coliform bacteria were always present at the same time as human enteric viruses. Two samples contained human enteric viruses but no fecal pollution indicators (E. coli, enterococci, or coliphages), suggesting the limited value of these microorganisms in predicting the presence of human enteric viruses in groundwater. Our results underline the value of historic data in assessing the vulnerability of a well on the basis of raw water quality and in detecting degradation of the source. This project allowed us to characterize the microbiologic and virologic quality of groundwater used as municipal drinking water sources in Quebec. 相似文献
5.
Landscape indicators, when combined with information about environmental conditions (such as habitat potential, biodiversity, carbon and nutrient cycling, and erosion) and socioeconomic forces, can provide insights about changing ecosystem services. They also provide information about opportunities for improving natural resources management. Landscape indicators rely on data regarding land cover, land management and land functionality. Challenges in using landscape indicators to assess change and effects include (1) measures of land management and attributes that are reliable, robust and consistent for all areas on the Earth do not exist, and thus land cover is more frequently utilized; (2) multiple types of land cover and management are often found within a single landscape and are constantly changing, which complicates measurement and interpretation; and (3) while causal analysis is essential for understanding and interpreting changes in indicator values, the interactions among multiple causes and effects over time make accurate attribution among many drivers of change particularly difficult. Because of the complexity, sheer number of variables, and limitations of empirical data on land changes, models are often used to illustrate and estimate values for landscape indicators, and those models have several problems. Recommendations to improve our ability to assess the effects of changes in land management include refinement of questions to be more consistent with available information and the development of data sets based on systematic measurement over time of spatially explicit land qualities such as carbon and nutrient stocks, water and soil quality, net primary productivity, habitat and biodiversity. Well-defined and consistent land-classification systems that are capable of tracking changes in these and other qualities that matter to society need to be developed and deployed. Because landscapes are so dynamic, it is crucial to develop ways for the scientific community to work together to collect data and develop tools that will enable better analysis of causes and effects and to develop robust management recommendations that will increases land's capacity to meet societal needs in a changing world. 相似文献
6.
In agrarian economy of developing nations like India, smallholder dairy production is an important enterprise and its sustainability is vital for ensuring livelihood and nutritional security to the masses. Studies on methodological aspects of farm sustainability at micro-level are limited, either confined to a particular dimension of sustainability or based on complex data requirement which is not feasible to obtain in the context of smallholder dairy farms. This study has developed a multi-attribute farm level sustainability assessment method encompassing economic, social and ecological dimensions of sustainability and has applied it to assess the sustainability of dairy farming in north-western part of India. Based on data from 120 dairy farms located in rural area of Jaipur district from the state of Rajasthan, the study computed the composite Sustainable Dairy Farming Index (SDFI). The overall substantiality status of the smallholder dairy farms in the study area was not encouraging, implying that it may not be viable for future generation to take up the enterprise. Among the three dimensions of sustainability, the average scores of ecological dimension were highest followed by the economic and social sustainability scores. Some of the core attributes like feed productivity, management of animal genetic potential and gender equality are particularly weak aspects of the dairy production system in India. The direct relationship of economic sustainability with herd size suggests for farmers with very small herds (one to two) animals, increasing the number of dairy animals to about five to six, would be a good strategy to economize on input costs and generate more marketed surplus of milk. 相似文献
7.
《Animal : an international journal of animal bioscience》2018,12(4):819-830
Recently developed innovations may improve the economic and environmental sustainability of pig production systems. Generic models are needed to assess the impact of innovations on farm performance. Here we developed a stochastic bio-economic farm model for a typical farrow-to-finish pig farm to assess the impact of innovations on private and social profits. The model accounts for emissions of greenhouse gases from feed production and manure by using the shadow price of CO2, and for stochasticity of economic and biological parameters. The model was applied to assess the impact of using locally produced alternative feed sources (i.e. co-products) in the diets of finishing pigs on private and social profits of a typical Brazilian farrow-to-finish pig farm. Three cases were defined: a reference case (with a standard corn–soybean meal-based finishing diet), a macaúba case (with a macaúba kernel cake-based finishing diet) and a co-products case (with a co-products-based finishing diet). Pigs were assumed to be fed to equal net energy intakes in the three cases. Social profits are 34% to 38% lower than private profits in the three cases. Private and social profits are about 11% and 14% higher for the macaúba case than the reference case, whereas they are 3% and 7% lower for the co-products case, respectively. Environmental costs are higher under the alternative cases than the reference case suggesting that other benefits (e.g. costs and land use) should be considered to utilize co-products. The CV of farm profits is between 75% and 87% in the three cases following from the volatility of prices over time and variations in biological parameters between fattening pigs. 相似文献
8.
9.
Daniel Leclair Jeffrey M. Farber Bill Doidge Burke Blanchfield Sandy Suppa Franco Pagotto John W. Austin 《Applied and environmental microbiology》2013,79(2):646-654
The distribution and levels of Clostridium botulinum type E were determined from field sites used by Inuit hunters for butchering seals along the coast of Nunavik. The incidence rates of C. botulinum type E in shoreline soil along the coast were 0, 50, and 87.5% among samples tested for the Hudson Strait, Hudson Bay, and Ungava Bay regions, respectively. Spores were detected in seawater or coastal rock surfaces from 17.6% of butchering sites, almost all of which were located in southern Ungava Bay. Concentrations of C. botulinum type E along the Ungava Bay coast were significantly higher than on the coasts of Hudson Strait and Hudson Bay, with the highest concentrations (270 to 1,800/kg of sample) found near butchering sites located along the mouths of large rivers. The Koksoak River contained high levels of C. botulinum type E, with the highest median concentration (270/kg) found in sediments of the marine portion of the river. C. botulinum type E was found in the intestinal contents (4.4%) and skins (1.4%) of seals. A high genetic biodiversity of C. botulinum type E isolates was observed among the 21 butchering sites and their surroundings along the Nunavik coastline, with 83% of isolates (44/53) yielding distinct pulsed-field gel electrophoresis genotypes. Multiple sources of C. botulinum type E may be involved in the contamination of seal meat during butchering in this region, but the risk of contamination appears to be much higher from environmental sources along the shoreline of southern Ungava Bay and the sediments of the Koksoak River. 相似文献
10.
Infections due to Trichophyton tonsurans and Trichophyton sulfureum in rural Eastern Quebec 总被引:3,自引:0,他引:3
Summary Seventy cases of dermatomycosis due toTrichophyton tonsurans (21 cases) andT. sulfureum (49 cases) were found in rural Quebec east of Rimouski during field investigations from 1956–1961. There are no immigrants in this area and endothrix ringworm has been present for at least three consecutive generations.Lesions due toT. tonsurans were restricted to the scalp, whereasT. sulfureum caused infections of the scalp, scalp and body or body alone. Both organisms were isolated from scalp infections of adults, 14 % of theT. tonsurans infections and 20 % of those due toT. sulfureum.Mixed infections due toT. tonsurans plusT. schönleinii andT. sulfureum plusM. canis were found.Each community, save one, harboured only one endothrix species, eitherT. tonsurans orT. sulfureum.These investigations were supported by a National Health Grant, Project 604-9-49. 相似文献
11.
In this study a new field of action for outcome-oriented payment schemes (payments by results) is introduced. That is the promotion of extensive summer grazing activities of livestock. Combining this objective with methods of outcome-oriented rewarding means to tie the payment to vegetation criteria indicating regular grazing activities instead of regularly controlling the presence of livestock on the field. In comparison to action-oriented concepts, the main advantage of this approach is that only one inspection walk is required. The paper describes and evaluates the first attempt to determine suitable indicator species for such a scheme. We pre-tested the approach with existing vegetation data only. A database of relevés, plant species and agriculturally used grassland communities of the regional district Doberan, Mecklenburg-Western Pomerania (Germany) was utilised. Grazing activities can be identified by the existence of a specific number of vascular species indicating grazing activities on a particular grassland field. We utilised the indicator function of grassland communities for management conditions to resolve the deficiency of data base relevés for providing no data about the management regime. The pasture community Lolio perennis-Cynosuretum cristati was used as a reference system to pre-test the suitability of different combinations of potential indicator species for separating pasture from non-pasture grassland. A tentative quantitative selection criterion for pasture grassland was proposed. That is the number of indicator species a relevé/grassland field has to hold to be identified as pasture grassland. Database relevés are not sufficient for calibrating such a concept, though. It is necessary to adjust the indicator species list to other drivers like use characteristics, nutrient availability, and soil moisture level. Here additional fieldwork is needed. As a first evidence for the validity of the concept, the suitability of the indicator list was measured by testing the correct identification of pasture grassland in a long-term grassland experiment built by the treatments “grazing” and “mowing”. ANOVA tests on the precision of the indicator species showed significant results. In the discussion a modification of the inventory method of grassland fields was recommended. The precision of the developed concept could be further enhanced by introducing the species dominance as a second factor deciding about the correct identification of pasture use. 相似文献
12.
Nathalie Fortin Rocio Aranda-Rodriguez Hongmei Jing Frances Pick David Bird Charles W. Greer 《Applied and environmental microbiology》2010,76(15):5105-5112
Toxic cyanobacterial blooms, as well as their increasing global occurrence, pose a serious threat to public health, domestic animals, and livestock. In Missisquoi Bay, Lake Champlain, public health advisories have been issued from 2001 to 2009, and local microcystin concentrations found in the lake water regularly exceeded the Canadian drinking water guideline of 1.5 μg liter−1. A quantitative PCR (Q-PCR) approach was developed for the detection of blooms formed by microcystin-producing cyanobacteria. Primers were designed for the β-ketoacyl synthase (mcyDKS) and the first dehydratase domain (mcyDDH) of the mcyD gene, involved in microcystin synthesis. The Q-PCR method was used to track the toxigenic cyanobacteria in Missisquoi Bay during the summers of 2006 and 2007. Two toxic bloom events were detected in 2006: more than 6.5 × 104 copies of the mcyDKS gene ml−1 were detected in August, and an average of 4.0 × 104 copies ml−1 were detected in September, when microcystin concentrations were more than 4 μg liter−1 and approximately 2 μg liter−1, respectively. Gene copy numbers and total microcystin concentrations (determined by enzyme-linked immunosorbent assay [ELISA]) were highly correlated in the littoral (r = 0.93, P < 0.001) and the pelagic station (r = 0.87, P < 0.001) in 2006. In contrast to the situation in 2006, a cyanobacterial bloom occurred only in late summer-early fall of 2007, reaching only 3 × 102 mcyDKS copies ml−1, while the microcystin concentration was barely detectable. The Q-PCR method allowed the detection of microcystin-producing cyanobacteria when toxins and toxigenic cyanobacterial abundance were still below the limit of detection by high-pressure liquid chromatography (HPLC) and microscopy. Toxin gene copy numbers grew exponentially at a steady rate over a period of 7 weeks. Onshore winds selected for cells with a higher cell quota of microcystin. This technique could be an effective approach for the routine monitoring of the most at-risk water bodies.Toxic cyanobacterial blooms, as well as their increasing global occurrence, pose a serious threat to human health, domestic animals, and livestock. The frequency and severity of bloom events continue to rise, most probably as a direct result of increased nutrient loading of water systems worldwide. The number of lakes in Quebec, Canada, affected by blooms of 2 × 104 cells ml−1 or more has been increasing from 21 (2004) to 28 (2005), 62 (2006), 157 (2007), 138 (2008), and 150 (2009). Government agencies are under tremendous pressure to cope with escalating demands for water analysis, specifically, for cyanotoxins.In Missisquoi Bay, Lake Champlain, public health advisories have been issued from 2001 to 2009 resulting in the closure of several beaches and periodic no-drinking warnings for the water. These advisories forbid any direct contact with the lake water by both people and animals because of the presence of cyanotoxins. The economic impact around the lake has been substantial, with revenues sometimes falling by 40 to 80% (20).For the past 8 years, microcystin (MCYST)-producing cyanobacterial genera have composed a major part of the bacterial community in Missisquoi Bay during both the summer and the fall. To date, five species known to produce toxins based on the literature (2) have been identified in the lake, including species of Microcystis and Anabaena (27).All species with microcystin-producing strains also include related strains that lack the ability to produce this toxin. The nonproducing strains cannot be differentiated by traditional microscopy or ribosomal gene sequences (15). Reliable tools to detect and characterize toxin-producing cyanobacteria are required. Enzyme-linked immunosorbent assay (ELISA) and high-pressure liquid chromatography (HPLC) are currently the most widely used techniques to evaluate whether toxins are present in water samples. The risk assessment response to the increasing occurrence of cyanotoxins has been seriously constrained due to the limited number of available standards and the limited analytical capability of some laboratories. At least 89 microcystin analogues have been characterized (35), but fewer than 10 reference standards are currently available.The development and validation of increasingly sensitive, specific, and reliable molecular tools will contribute to the next generation of monitoring approaches. The detection and quantitation of specific target genes, such as those involved in the synthesis of toxins in cyanobacteria, are the cornerstone of new techniques to identify, monitor, or profile specific targets in environmental samples. These approaches are in general less expensive and faster than the currently available chemical assays and do not rely on reference standards.The structure of the microcystin biosynthesis cluster of two strains of Microcystis aeruginosa (17, 18, 31), Planktothrix agardhii NIVA CYA 126/8 (3), and Anabaena sp. strain 90 (28) which encodes the nonribosomal peptide synthetase-polyketide synthase enzyme complex has been elucidated. The mcy gene cluster is located on the chromosome and contains 10 genes (mcyA to mcyJ). The two polyketide synthase modules of mcyG and mcyE, together with the two polyketide synthase modules of mcyD, are responsible for the synthesis of the unique Adda moiety of microcystins. The Adda side chain is largely responsible for the toxicity through protein phosphatase inhibition (7, 8, 12).The number of water bodies affected by cyanobacterial blooms has been increasing worldwide, and scientists have designed primers for the various genes involved in the biosynthesis of microcystins. The mcyD gene has been used in conventional PCR for phylogenetic studies (16, 22, 29) and as a target to characterize cyanobacterial blooms in Lakes Ontario (11) and Erie (19). The mcyE gene has also been targeted to design genus-specific primers (23, 24, 33) and universal primers encoding the aminotransferase domain of various genera of cyanobacteria (4, 13). All of these primers generated PCR fragments that were larger than the recommended size for quantitative PCR (Q-PCR) (100 to 200 bp).A Q-PCR technique, the Taq nuclease assay, was developed by Rinta-Kanto and colleagues (25, 26) to study the distribution and abundance of toxic Microcystis blooms in western Lake Erie. In their first study, the mcyD probe was highly specific to Microcystis species but failed to detect the mcyD gene in one of the samples that had a detectable concentration of microcystin in the water. Other microcystin-producers, such as Anabaena and Planktothrix, were identified in that sample and were likely responsible for toxin production.The number of gene sequences related to microcystin biosynthesis in the databases has been increasing rapidly since the beginning of 2000. The objectives of this study were to develop a rapid, Q-PCR-based technique for detecting and monitoring the dynamics of microcystin-producing cyanobacteria and to determine the correlation between toxigenic cells and toxin concentration. The mcyD gene was selected as the specific target for characterizing cyanobacterial blooms and applied in Missisquoi Bay, Lake Champlain, during the summers of 2006 and 2007. Oligonucleotide primers were designed based on the alignments of all 50 mcyD nucleotide sequences available in GenBank as of March 2006 and were verified in December 2009. The alignments revealed that the polyketide synthase sequences were divided into three major clusters: some of the submitted sequences encoded the first dehydratase domain, others were from one of the β-ketoacyl synthases and the third group of sequences encoded part of both the ketoacetyl synthase and the acetyltransferase domains. Primers were designed to create PCR fragments from two different regions of the mcyD gene. These fragments were cloned to create a standard curve for absolute quantification. This strategy was chosen to ensure that the quantification of cells carrying the target gene would be performed with a standard curve that originated from a single gene copy. 相似文献
13.
In 2006, the golden cyst nematode, Globodera rostochiensis, was discovered in the province of Quebec, Canada. We report here the life cycle of G. rostochiensis under the climatic conditions of southwestern Quebec. Only one full generation was completed per year under these latitudes. On susceptible potato cv. Snowden, G. rostochiensis needed a minimum of 579 growing degree units (GDU) (base 5.9°C) to complete its life cycle and the first mature cysts were observed 42 to 63 days after planting (DAP). In soil, second-stage juveniles (J2) were first observed 14 to 21 DAP, whereas both white females on roots and males in soil appeared synchronously after 35 to 42 days. The duration of the life cycle was affected by temperature but not by soil type. A second wave of hatching systematically occurred later in the season and a second generation of males was observed during the 2011 growth season. No complete second cycle was observed before plant senescence. Climate change and later maturing cultivars/crops could allow the development of a full second generation in the future. 相似文献
14.
J Daigneault G Aubin F Simard M De Braekeleer 《Human biology; an international record of research》1992,64(1):115-119
The incidence of cystic fibrosis (CF) in Saguenay-Lac-St.-Jean, a geographically isolated region of Quebec, was estimated to be 1 in 902 during the period 1975-1988. The carrier rate was calculated to be 1 in 15 inhabitants. The high incidence of CF in Saguenay-Lac-St.-Jean is probably the result of a founder effect and genetic drift for one or more mutations. Historical, demographic, and social factors also may have contributed to the high incidence. 相似文献
15.
Nelson Thiffault Pierre Grondin Jean Noël Véronique Poirier 《Ecology and evolution》2015,5(9):1837-1853
Understory species play a significant role in forest ecosystem dynamics. As such, species of the Ericaceae family have a major effect on the regeneration of tree species in boreal ecosystems. It is thus imperative to understand the ecological gradients controlling their distribution and abundance, so that their impacts can be taken into account in sustainable forest management. Using innovative analytical techniques from landscape ecology, we aimed to position, along ecological gradients, four Ericaceae found in the boreal forest of Quebec (Canada) (Rhododendron groenlandicum, Kalmia angustifolia, Chamaedaphne calyculata, and Vaccinium spp), to regionalize these species into landscape units relevant to forest management, and to estimate the relative importance of several ecological drivers (climate, disturbances, stand attributes, and physical environment) that control the species distribution and abundance. We conducted our study in boreal Quebec, over a study area covering 535,355 km2. We used data from 15,339 ecological survey plots and forest maps to characterize 1422 ecological districts covering the study region. We evaluated the relative proportion of each ericaceous species and explanatory variables at the district level. Vegetation and explanatory variables matrices were used to conduct redundancy, cluster, and variation partitioning analyses. We observed that ericaceous species are mainly distributed in the western part of the study area and each species has a distinct latitudinal and longitudinal gradient distribution. On the basis of these gradients, we delimited 10 homogeneous landscape units distinct in terms of ericaceous species abundance and environmental drivers. The distribution of the ericaceous species along ecological gradients is closely related to the overlaps between the four sets of explanatory variables considered. We conclude that the studied Ericaceae occupy specific positions along ecological gradients and possess a specific abundance and distribution controlled by the integration of multiple explanatory variables. 相似文献
16.
Hereditary hemochromatosis (HH) is an autosomal recessive disorder that has a high prevalence in Caucasian populations. Based on HLA typing in 18 families, the gene frequency was estimated 0.12. The homozygote frequency was 0.014 and the heterozygote frequency was 0.21 in Saguenay Lac-Saint-Jean (SLSJ), a geographically isolated region of northeastern Quebec. The genealogical reconstruction showed that 15 of the 57 obligate carriers of the HH gene could be traced back to a unique ancestor in the 18th century. The mean coefficients of inbreeding and kinship were 17 and 15 times, respectively, higher in the HH group than in three control groups. The values of both coefficients were much higher than those found in other HH populations and in most of the other recessive disorders prevalent in SLSJ. 相似文献
17.
M.T. Southerland G.M. Rogers M.J. Kline R.P. Morgan D.M. Boward P.F. Kazyak R.J. Klauda S.A. Stranko 《Ecological Indicators》2007,7(4):751-767
Biological indicators of stream condition are in use by water resource managers worldwide. The State of Maryland and many other organizations that use Indices of Biotic Integrity (IBIs) must determine when and how to refine their IBIs so that better stream condition information is provided. With completion of the second statewide round in 2004, the Maryland Biological Stream Survey (MBSS) had collected data from 2500 stream sites, more than doubling the number of sites that were available for the original IBI development. This larger dataset provided an opportunity for the MBSS to address the following shortcomings in the original IBIs: (1) substantial disturbance apparent in some reference sites, (2) fish IBIs could not be applied to very small streams, (3) natural variability within IBIs (based on regions) resulted in some stream types (e.g., coldwater and blackwater streams) receiving lower IBI scores and (4) one IBI was not able to discriminate degradation as desired (i.e., Coastal Plain fish IBI). Therefore, development of new fish and benthic macroinvertebrate IBIs was undertaken to achieve the goals of: (1) increased confidence that the reference conditions are minimally disturbed, (2) including more natural variation (such as stream size) across the geographic regions and stream types of Maryland and (3) increased sensitivity of IBIs by using more classes (strata) and different metric combinations. New fish IBIs were developed for four geographical and stream type strata: Coastal Plain, Eastern Piedmont, warmwater Highlands and coldwater Highlands streams; new benthic macroinvertebrate IBIs were developed for three geographical strata: Coastal Plain, Eastern Piedmont and Highlands streams. The addition of one new fish IBI and one new benthic macroinvertebrate IBI partitioned natural variability into more homogeneous strata. At the same time, smaller streams (i.e., those draining catchments <300 ac), which constituted a greater proportion of streams (25%) sampled in Round Two (2000–2004) than Round One (1995–1997), because of the finer map scale, were included in the reference conditions used to develop the new IBIs. The resulting new IBIs have high classification efficiencies of 83–96% and are well balanced between Type I and Type II errors. By scoring coldwater streams, smaller streams and to some extent blackwater streams higher, the new IBIs improve on the original IBIs. Overall, the new IBIs provide better assessments of stream condition to support sound management decisions, without requiring substantial changes by cooperating stream assessment programs. 相似文献
18.
There are high numbers of endangered birds in Iran. Birds also are indicators of biodiversity in different landscapes and using birds as indicator give us a complete overview about the ecological status of the landscape. In the present study migratory waterfowls were used to identify biodiversity hotspots in Iran. Iran is an interesting place for ornithologists because it is in fact a crossroads of flyways for migratory waterfowls coming from Europe, southern Asia, and Siberia. We predicted the habitat distributions for 27 bird species of Anseriformes in Iran using an ensemble forecasting framework to identify biodiversity hotspots. Moreover, we measured the percentage of overlap between hotspots and protected areas including Ramsar sites. The results showed that suitable habitats for different bird species greatly varied among different ecosystems and they showed dissimilar responses to environmental variables. However, for most species digital elevation model (DEM) was the most important variable in predicting suitable habitats. Our study also revealed that 36.02% of Iran can be considered as suitable habitats for the species and the highest suitability belongs to areas along Zagros and Alborz mountain ranges. Furthermore, the suitable habitats had 7.10% overlap with protected areas and 75% with Ramsar sites. The low overlap between hotspots and protected areas demonstrated the shortage of biodiversity protection in Iran. Therefore, it is essential to select new protected areas based on biodiversity hotspots, and to develop a network of protected areas within those hotspots in Iran. 相似文献
19.
旅游生态足迹:测度旅游可持续发展的新方法 总被引:68,自引:7,他引:68
生态足迹分析方法是近年发展起来的一种主要用面积来定量测度人类对自然资源利用程度和可持续发展的新方法。旅游生态足迹是生态足迹理念在旅游研究中的应用,有助于对旅游活动的生态需求与环境影响关系的理解,可以用面积来对旅游可持续发展进行定量测度。论述旅游生态足迹基本概念,并以线路旅游产品为例,在阐述生态足迹的计算步骤和方法的基础之上,主要探讨旅游生态足迹在旅游可持续发展中6个方面的测度功能旅游产业、旅游产品、旅游目的地、企业生态、旅游者及大众旅游,对旅游生态足迹的进一步研究具有重要理论指导意义。 相似文献
20.
WENDY GIROUX PIERRE BLANCHETTE JEAN-CLAUDE BOURGEOIS GILBERT CABANA 《The Journal of wildlife management》2007,71(1):87-95
Abstract: Adequate cover is a critical component of ruffed grouse (Bonasa umbellus) habitat during the brood-rearing period when chick mortality is high. We assessed habitat use by ruffed grouse during the brood-rearing period by comparing characteristics of tree, shrub, and ground layers at ruffed grouse brood and random locations. We captured and radiomarked 29 females with broods in 2 forest settings of the Réserve faunique de Portneuf, Quebec, Canada. We described grouse habitat using ground surveys and forest maps, and we identified the used habitat characteristics using analysis of variance and logistic regression. Females with broods used mixed and regenerated clearcut stands that were 1.5–7 m tall and 11–20 years old. Compared with random locations, grouse locations had higher lateral obstruction (76% vs. 68%), higher small-stem density (29,085 stems/ha vs. 19,340 stems/ha), and were closer to roads and trails. Percentage of coverage by ground vegetation was not higher at grouse locations as often reported in previous studies. Results from this study will help orient ruffed grouse habitat management on Quebec public land and elsewhere in nordic—temperate mixed hardwood—softwood forests to maintain suitable brood habitat after logging operations. Forest management should promote growth of young mixed stands with high horizontal and vertical cover provided by high small-stem density, which offers protection against aerial and terrestrial predation. Edges such as roadsides are also important in brood habitat as they provide food and cover. 相似文献