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1.
River restoration is an integral part of restoring the Chesapeake Bay. As part of the National River Restoration Science Synthesis (NRRSS), we conducted 47 independent interviews with stream restoration project managers randomly selected from a database of 4,700 projects in the Chesapeake Bay watershed. Here we present results from those interviews and characterize patterns in project goals, design, and expenditures, trends in project evaluation, and characterize project success as reported by interviewees. Interviewed practitioners reported that the majority of their projects were designed by private consultants. One‐third of projects were part of a watershed management plan and 70% were linked to other projects within the same watershed. Most interviewees considered their projects to be successful, and 76% of projects had conducted some form of project‐associated monitoring. Although most interviewees based their evaluation of success on observations or monitoring data, respondents indicated that very few projects had explicitly stated quantifiable project objectives within their design plans. Many interviewed practitioners specifically commented at the end of the surveys on the important role of stakeholder involvement and the need for initiatives to fund project monitoring.  相似文献   

2.
Stream restoration has become a multibillion dollar industry worldwide, yet there are few clear success stories and the scientific basis for effective stream restoration remains uncertain. We compiled data on completed river restoration projects from four management authorities in Victoria, Australia, to examine how the available data could inform the science of restoration ecology in rivers, and thus improve future restoration efforts. We found that existing data sources are limited and much historical information has been lost through industry restructuring and poor data archiving. Examining records for 2,247 restoration projects, we found that riparian management projects were the most common, followed by bank stabilization and in‐stream habitat improvement. Only 14% of the project records indicated that some form of monitoring was carried out. It is evident that overall there is little scientific guidance and little or no monitoring and evaluation of the projects for which we had information. However, recent advances with mandatory, statewide reporting and an increased emphasis on project design and monitoring strongly suggest that the design, implementation, monitoring, and reporting of stream restoration projects have improved in recent years and will continue to do so.  相似文献   

3.
Across the Pacific Northwest (PNW), both public and private agents are working to improve riverine habitat for a variety of reasons, including improving conditions for threatened and endangered salmon. These projects are moving forward with little or no knowledge of specific linkages between restoration actions and the responses of target species. Targeted effectiveness monitoring of these actions is required to redress this lack of mechanistic understanding, but such monitoring depends on detailed restoration information—that is, implementation monitoring. This article describes the process of assembling a database of restoration projects intended to improve stream and river habitat throughout the PNW. We designed the database specifically to address the needs of regional monitoring programs that evaluate the effectiveness of restoration actions. The database currently contains spatially referenced, project‐level data on over 23,000 restoration actions initiated at over 35,000 locations in the last 15 years (98% of projects report start or end dates between 1991 and 2005) in the states of Washington, Oregon, Idaho, and Montana. Data sources included federal, state, local, nongovernmental organization, and tribal contributors. The process of database production identified difficulties in the design of regional project tracking systems. The technical design issues range from low‐level information such as what defines a project or a location to high‐level issues that include data validation and legalities of interagency data sharing. The completed database will inform efficient monitoring design, effectiveness assessments, and restoration project planning.  相似文献   

4.
Bacterial wilt, caused by Ralstonia solanacearum, is a serious disease of tobacco in North and South Carolina. In contrast, the disease rarely occurs on tobacco in Georgia and Florida, although bacterial wilt is a common problem on tomato. We investigated whether this difference in disease incidence could be explained by qualitative characteristics of avirulence gene avrA in the R. solanacearum population in the southeastern United States. Sequence analysis established that wild-type avrA has a 792-bp open reading frame. Polymerase chain reaction (PCR) amplification of avrA from 139 R. solanacearum strains generated either 792-bp or approximately 960-bp DNA fragments. Strains that elicited a hypersensitive reaction (HR) on tobacco contained the 792-bp allele, and were pathogenic on tomato and avirulent on tobacco. All HR-negative strains generated a approximately 960-bp DNA fragment, and wilted both tomato and tobacco. The DNA sequence of avrA in six HR-negative strains revealed the presence of one of two putative miniature inverted-repeat transposable elements (MITEs): a 152-bp MITE between nucleotides 542 and 543, or a 170-bp MITE between nucleotides 461 and 462 or 574 and 575. Southern analysis suggested that the 170-bp MITE is unique to strains from the southeastern United States and the Caribbean. Mutated avrA alleles were present in strains from 96 and 75% of North and South Carolina sites, respectively, and only in 13 and 0% of the sites in Georgia and Florida, respectively. Introduction of the wildtype allele on a plasmid into four HR-negative strains reduced their virulence on both tobacco and tomato. Inactivation of avrA in an HR-positive, avirulent strain, resulted in a mutant that was weakly virulent on tobacco. Thus, the incidence of bacterial wilt of tobacco in the southeastern United States is partially explained by which avrA allele dominates the local R. solanacearum population.  相似文献   

5.
Restoration activity has exponentially increased across the Southwest since 1990. Over 37,000 records were compiled into the National River Restoration Science Synthesis (NRRSS) database to summarize restoration trends and assess project effectiveness. We analyzed data from 576 restoration projects in the Southwest (NRRSS‐SW). More than 50% of projects were less than or equal to 3 km in length. The most common restoration project intent categories were riparian management, water quality management, in‐stream habitat improvement, and flow modification. Common project activities were well matched to goals. Conservative estimates of total restoration costs exceeded $500 million. Most restoration dollars have been allocated to flow modification and water quality management. Monitoring was linked to 28% of projects across the Southwest, as opposed to just 10% nationwide. Mean costs were statistically similar whether or not projects were monitored. Results from 48 telephone interviews provided validation of NRRSS‐SW database analyses but showed that project costs are often underreported within existing datasets. The majority of interviewees considered their projects to be successful, most often based upon observed improvements to biota or positive public reaction rather than evaluation of field data. The efficacy of restoration is difficult to ascertain given the dearth of information contained within most datasets. There is a great need for regional entities that not only track information on project implementation but also maintain and analyze monitoring data associated with restoration. Agencies that fund or regulate restoration should reward projects that emphasize monitoring and evaluation as much as project implementation.  相似文献   

6.
The distribution of Spiculopteragia pursglovei (= Apteragia pursglovei) and S. odocoilei (= A. odocoilei) in 12 southeastern states was determined after examining the abomasal contents of 1,369 white-tailed deer over an 8-yr period. Spiculopteragia odocoilei was encountered with much greater frequency than S. pursglovei except in some areas along the Mississippi River drainage and the coasts of North Carolina and South Carolina. In instances where both parasites were found in a population, one usually expressed a dominance in both prevalence and intensity. These findings are in agreement with those of an earlier study conducted in the southeastern United States.  相似文献   

7.
Although public and financial support for stream restoration projects is increasing, long‐term monitoring and reporting of project successes and failures are limited. We present the initial results of a long‐term monitoring program for the Lower Red River Meadow Restoration Project in north‐central Idaho, U.S.A. We evaluate a natural channel design’s effectiveness in shifting a degraded stream ecosystem onto a path of ecological recovery. Field monitoring and hydrodynamic modeling are used to quantify post‐restoration changes in 17 physical and biological performance indicators. Statistical and ecological significance are evaluated within a framework of clear objectives, expected responses (ecological hypotheses), and performance criteria (reference conditions) to assess post‐restoration changes away from pre‐restoration conditions. Compared to pre‐restoration conditions, we observed ecosystem improvements in channel sinuosity, slope, depth, and water surface elevation; quantity, quality, and diversity of in‐stream habitat and spawning substrate; and bird population numbers and diversity. Modeling documented the potential for enhanced river–floodplain connectivity. Failure to detect either statistically or ecologically significant change in groundwater depth, stream temperature, native riparian cover, and salmonid density is due to a combination of small sample sizes, high interannual variability, external influences, and the early stages of recovery. Unexpected decreases in native riparian cover led to implementation of adaptive management strategies. Challenges included those common to most project‐level monitoring—isolating restoration effects in complex ecosystems, securing long‐term funding, and implementing scientifically rigorous experimental designs. Continued monitoring and adaptive management that support the establishment of mature and dense riparian shrub communities are crucial to overall success of the project.  相似文献   

8.
Despite expenditures of more than 1 billion dollars annually, there is little information available about project motivations, actions, and results for the vast majority of river restoration efforts. We performed confidential telephone interviews with 317 restoration project managers from across the United States with the goals of (1) assessing project motivations and the metrics of project evaluation and (2) estimating the proportion of projects that set and meet criteria for ecologically successful river restoration projects. According to project managers, ecological degradation typically motivated restoration projects, but post‐project appearance and positive public opinion were the most commonly used metrics of success. Less than half of all projects set measurable objectives for their projects, but nearly two‐thirds of all interviewees felt that their projects had been “completely successful.” Projects that we classified as highly effective were distinct from the full database in that most had significant community involvement and an advisory committee. Interviews revealed that many restoration practitioners are frustrated by the lack of funding for and emphasis on project monitoring. To remedy this, we recommend a national program of strategic monitoring focused on a subset of future projects. Our interviews also suggest that merely conducting and publishing more scientific studies will not lead to significant improvements in restoration practice; direct, collaborative involvement between scientists, managers, and practitioners is required for forward progress in the science and application of river restoration.  相似文献   

9.
Despite some highly visible projects that have resulted in environmental benefits, recent efforts to quantify the number and distribution of river restoration projects revealed a paucity of written records documenting restoration outcomes. Improving restoration designs and setting watershed priorities rely on collecting and making accessible this critical information. Information within the unpublished notes of restoration project managers is useful but rarely documents ecological improvements. This special section of Restoration Ecology is devoted to the current state of knowledge on river restoration. We provide an overview of the section’s articles, reflecting on lessons learned, which have implications for the implementation, legal, and financing frameworks for restoration. Our reflections are informed by two databases developed under the auspices of the National River Restoration Science Synthesis project and by extensive interactions with those who fund, implement, and permit restoration. Requiring measurable ecological success criteria, comprehensive watershed plans, and tracking of when and where restoration projects are implemented are critical to improving the health of U.S. waters. Documenting that a project was put in the ground and stayed intact cannot be equated with ecological improvements. However, because significant ecological improvements can come with well‐designed and ‐implemented stream and river restorations, a small investment in documenting the factors contributing to success will lead to very large returns in the health of our nation’s waterways. Even projects that may appear to be failures initially can be turned into success stories by applying the knowledge gained from monitoring the project in an adaptive restoration approach.  相似文献   

10.
Stream Restoration in the Upper Midwest, U.S.A.   总被引:1,自引:0,他引:1  
Restoration activities intended to improve the condition of streams and rivers are widespread throughout the Upper Midwest, U.S.A. As with other regions, however, little information exists regarding types of activities and their effectiveness. We developed a database of 1,345 stream restoration projects implemented from the years 1970 to 2004 for the states of Michigan, Ohio, and Wisconsin in order to analyze regional trends in goals, presence of monitoring, spatial distribution, size, and cost of river restoration projects. We found that data on individual projects were fragmented across multiple federal, state, and county agencies, as well as nonprofit groups and consulting firms. The most common restoration goals reported for this region were in‐stream habitat improvement, bank stabilization, water‐quality management, and dam removal. The former two were most common in Michigan and Wisconsin, where salmonid fisheries enhancement appeared to be an important concern, whereas water‐quality management was most frequent in Ohio. The most common restoration activities were the use of sand traps and riprap, and other common activities were related to the improvement of fish habitat. The median cost was $12,957 for projects with cost data, and total expenditures since 1990 were estimated at $444 million. Over time, the cost of individual projects has increased, whereas the median size has decreased, suggesting that restoration resources are being spent on smaller, more localized, and more expensive projects. Only 11% of data records indicated that monitoring was performed, and more expensive projects were more likely to be monitored. Standardization of monitoring and record keeping and dissemination of findings are urgently needed to ensure that dollars are well spent and restoration effectiveness is maximized.  相似文献   

11.
Channel reconfiguration is one of the most common and costly stream restoration techniques, though its effectiveness is frequently questioned. Project monitoring often tracks changes in macroinvertebrate communities and other responses for a 5‐year period. However, channel reconfiguration is a documented disturbance to stream ecosystems, suggesting that this form of restoration initiates succession over longer time frames than monitoring typically captures. To address the role of succession in stream ecosystem recovery, we developed the Phased Recovery Framework (PRF) which proposes benchmarks represented by predictable habitat structure and community composition based on project age. The PRF was tested across nine stream restoration projects in western Montana, ranging in age from 1 to 18 years, each paired with an established reference system. We tested for differences in channel form, habitat character, and macroinvertebrate community composition. While restoration established desired channel form, most biotic variables had not recovered to reference condition even for the oldest projects. Across all sites, phases of the PRF were poor predictors of response. However, analyzing responses to reconfiguration independently for sites in watersheds with unimpaired water quality versus those experiencing excessive nutrient enrichment (i.e. impaired sites) indicated that biological variables converged on reference conditions at unimpaired sites, but diverged across impaired reaches. These large‐scale anthropogenic influences may play a stronger role in recovery than do changes to channel form and need to be incorporated into project design and success criteria. Assessment of the PRF suggests that short‐term monitoring is not likely to produce reliable indicators of effectiveness without incorporating locally appropriate change associated with watershed impairment and successional progression.  相似文献   

12.
Stream and river ecosystems have suffered extensive degradation, and billions are expended annually on restoration efforts. However, few of these projects are monitored, and restoration effectiveness is often unknown. Consequently, there is a poor scientific foundation for restoration designs. Since many stream restoration efforts are at least partially targeted at controlling erosion of channel banks and beds, the effects of a large-scale, long-term stream erosion control effort in six Mississippi watersheds was assessed using 10–16 years of suspended sediment and water discharge records. Flow-adjusted suspended sediment concentrations showed no trends in five of the watersheds and a slight downward trend in one watershed, which was treated with small reservoirs as well as bed and bank erosion protection. Results indicate the inability of orthodox stream management structures (weirs and bank protection) to reduce watershed sediment yield and the need for a stronger scientific basis for stream restoration.  相似文献   

13.
美国大陆五个山区集水区的河溪结构分析   总被引:3,自引:0,他引:3  
河溪结构及其关联的空间特征,是研究集水区中能量和物质移动规律所不可缺少的内容,利用美国地质调查局的水文数据库和地理信息系统(ARC/INFO),对美国大陆5个主要山地中典型集水区河溪的数据量、密度,分布结构以及河溪岸边带的组成,进行了分析和比较。5个山地分别是:西北太平洋沿岸,西部卡斯卡特山,中部落矶山,东部阿巴拉契亚山和南部欧扎克山,发现这5个集水区中的河溪网络结构非常相似,一级河溪大约占河溪总  相似文献   

14.
Conservation and restoration of riparian vegetation in agricultural landscapes has had mixed success at protecting in‐stream habitat, potentially due to the mismatch between watershed‐scale impacts and reach‐scale restoration. Prioritizing contiguous placement of small‐scale restoration interventions may effectively create larger‐scale restoration projects and improve ecological outcomes. We performed a multi‐site field study to evaluate whether greater linear length of narrow riparian tree corridors resulted in measurable benefits to in‐stream condition. We collected data at 41 sites with varying upstream tree cover nested within 13 groups in rangeland streams in coastal northern California, United States. We evaluated the effect of riparian tree corridor length on benthic macroinvertebrate communities, as well as food resources, water temperature, and substrate size. Sites with longer riparian corridors had higher percentages of invertebrates sensitive to disturbance (including clingers and EPT taxa) as well as lower water temperatures and less fine sediment, two of the most important aquatic stressors. Despite marked improvement, we found no evidence that macroinvertebrate communities fully recovered, suggesting that land use continued to constrain conditions. The restoration of long riparian corridors may be an economically viable and rapidly implementable technique to improve habitat, control sediment, and counter increasing water temperatures expected with climate change within the context of ongoing land use.  相似文献   

15.
Food forests—edible, perennial, polyculture systems—are of increasing interest in North America and the United Kingdom, as reflected in projects ranging from urban food initiatives to integrated conservation and restoration planning. To examine emerging food forestry (FF) against the backdrop of ecological restoration (ER), we conducted semi‐structured interviews with eight experts each from the fields of FF and ER in conjunction with observations of food forests in Canada, the United States, and the United Kingdom. Using content analysis, our study builds a FF model that encompasses the underlying goals of emerging FF—forest function; diversity of yields; education and culture sharing; healthy habitats for people and other species; and sustainability. We argue that FF has potential as an urban restoration tool in terms of enhancing the multifunctionality of heterogeneous landscapes undergoing significant changes. This will require meaningful consideration of ethical issues (e.g. commodification of nature), landscape contexts, ecological integrity, integration of historical knowledge, and resilience for interdependent, dynamic social and ecological systems. Moreover, systematic, long‐term monitoring of different types of food forests will be crucial in order to mindfully apply FF in ER. This research provides one of the first in‐depth analyses of how emerging FF might contribute to restoration in the time of the Anthropocene, especially outside traditional tropic regions where most FF has been practiced.  相似文献   

16.
Two Decades of River Restoration in California: What Can We Learn?   总被引:4,自引:0,他引:4  
As part of the National River Restoration Science Synthesis (NRRSS), we developed a summary database of 4,023 stream restoration projects built in California since 1980, from which we randomly selected 44 records for in‐depth interviews with project managers. Despite substantial difficulties in gathering the data, we were able to draw conclusions about current design, implementation, monitoring, and evaluation practices used in California projects and compare them with national trends. Although more than half of the projects for which we conducted interviews were located in watersheds for which a management or assessment plan had been prepared, these plans had a limited impact on site selection. We also found that the state lacks a consistent framework for design, monitoring, and reporting restoration projects, and that although monitoring is far more widespread than the information in the NRRSS summary database would suggest, there are still problems with the type, duration, and reporting of monitoring. The general lack of systematic, objective assessment of completed projects hinders the advance of restoration science.  相似文献   

17.
The once widespread Longleaf pine (Pinus palustris)–dominated ecosystems of the southeastern coastal plain of the United States have been greatly reduced in extent, and many of the remaining stands are being degraded by hardwood invasion due to fire suppression. The first step toward pine savanna restoration is often hardwood removal, a costly process due to their large volumes and low market values. Despite these problems, by marketing a wide range of hard‐ and softwood products, the costs of 13 restoration projects in northern Florida were substantially reduced. Ten different products were sold to 19 different buyers. Fuel chips represented 71–100% of all biomass removed (8.2–81.1 Mg/ha). Although landowners were charged modest amounts for removing biomass harvested as fuel chips, other marketed products yielded revenues. Overall, four projects earned net profits of $29–$383/ha, and four projects generated sufficient revenue to pay 17–99% of the cost of hardwood removal as fuel chips. A carbon accounting of a second set of projects demonstrated that carbon harvested as fuel chips far exceeded that consumed in harvest and transport, yielding net carbon offsets of 451–1,320 Mg C/project (3.3–13.9 Mg C/ha). Using fuel consumption results of this second set of projects, carbon offsets for the 13 restoration projects were estimated as 89–1,524 Mg (3.8–37.9 Mg C/ha). Restorationists should monitor traditional forest product markets as well as developing carbon markets for price fluctuations that could provide significant revenues to restoration projects.  相似文献   

18.
The southeastern United States harbors an unusually large number of endemic plant taxa, which may reflect the refugial nature of the region during Pleistocene glacial maxima. Understanding the genetic diversity and structure of extant plant taxa can provide insights into the biogeographical processes that shaped them genetically. Here, we investigate the levels and partitioning of allozyme diversity in the southeastern North American endemic, Ceratiola ericoides, which displayed greater genetic variation and structure than other endemics. Central Florida populations represent a center of genetic diversity, whereas South Carolina and Georgia Fall Line sandhill populations have a subset of the Central Florida genetic diversity and may be relicts of a once continuous distribution. This much broader, continuous distribution throughout the southeastern United States occurred during glacial maxima when the scrub habitat, dominated by C. ericoides, expanded considerably owing to drier climatic conditions. Georgia Coastal Plain populations appear to have been independently founded more recently by propagules from Central Florida and the Fall Line sandhills because they have an even more limited subset of genetic diversity and greater genetic heterogeneity among populations. Since their establishment, coastal plain populations appear to have had little, if any, gene exchange among each other or with the relatively proximate Fall Line sandhill populations. These data underscore the importance of understanding the genetic composition and historical biogeography of species before intelligent management or restoration decisions can be made regarding their preservation.  相似文献   

19.
Prior to 1900, coyotes (Canis latrans) were restricted to the western and central regions of North America, but by the early 2000s, coyotes became ubiquitous throughout the eastern United States. Information regarding morphological and genetic structure of coyote populations in the southeastern United States is limited, and where data exist, they are rarely compared to those from other regions of North America. We assessed geographic patterns in morphology and genetics of coyotes with special consideration of coyotes in the southeastern United States. Mean body mass of coyote populations increased along a west‐to‐east gradient, with southeastern coyotes being intermediate to western and northeastern coyotes. Similarly, principal component analysis of body mass and linear body measurements suggested that southeastern coyotes were intermediate to western and northeastern coyotes in body size but exhibited shorter tails and ears from other populations. Genetic analyses indicated that southeastern coyotes represented a distinct genetic cluster that differentiated strongly from western and northeastern coyotes. We postulate that southeastern coyotes experienced lower immigration from western populations than did northeastern coyotes, and over time, genetically diverged from both western and northeastern populations. Coyotes colonizing eastern North America experienced different selective pressures than did stable populations in the core range, and we offer that the larger body size of eastern coyotes reflects an adaptation that improved dispersal capabilities of individuals in the expanding range.  相似文献   

20.
Hundreds of millions of dollars per year are spent on river restoration in the Pacific Northwest (PNW), but little is known about the effectiveness of this effort. To help address this gap, we analyzed a database containing 23,000 projects at 35,000 locations in the region. We selected a subset of these projects for interviews using a survey instrument developed by a national team of scientists. In total, 47 project contacts in the PNW were interviewed to learn from the individuals directly involved in restoration. At least one‐third of the projects surveyed (34%) did not conduct sufficient monitoring to evaluate effectiveness. More than two‐thirds (70%) of all respondents reported their projects were successful, but 43% either have no success criteria or are unaware of any criteria for their project. Although almost two‐thirds (66%) of respondents anticipate a need for ongoing project maintenance, less than half (43%) have maintenance funds available. These findings suggest that establishing a connection between effectiveness monitoring and project implementation is not a usual component of project design. Consequently, we can only assess the benefits in a few isolated projects and cannot quantify the cumulative benefits of restoration on a larger scale. These findings highlight the need for (1) planning prior to implementation of restoration projects that accounts for monitoring design; (2) coordinated effectiveness monitoring to assess cumulative effects of restoration; and (3) management and maintenance of projects based on real measures of project performance.  相似文献   

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