Comparison of Marine and Terrestrial Protected Areas under Federal Jurisdiction in the United States

Abstract: There is a significant disparity in the protection of terrestrial and marine environments in the United States. Despite the considerable literature dedicated to the subject of protected areas, both terrestrial and marine, in the United States, we are not aware of work explicitly describing this dichotomy. We compared marine and terrestrial areas under federal jurisdiction to provide a quantitative assessment of the differences between the conservation of land and sea in the United States. Specifically, we compared national marine sanctuaries (including sanctuary preservation areas and ecological reserves) with national parks, national forests, and national wildlife refuges (including national wilderness preservation areas). Our results suggest that marine sanctuaries are fewer in number, smaller in total area, and smaller in percentage of area covered than are terrestrial protected areas.     

Postfire Management on Forested Public Lands of the Western United States

Abstract:  Forest ecosystems in the western United States evolved over many millennia in response to disturbances such as wildfires. Land use and management practices have altered these ecosystems, however, including fire regimes in some areas. Forest ecosystems are especially vulnerable to postfire management practices because such practices may influence forest dynamics and aquatic systems for decades to centuries. Thus, there is an increasing need to evaluate the effect of postfire treatments from the perspective of ecosystem recovery. We examined, via the published literature and our collective experience, the ecological effects of some common postfire treatments. Based on this examination, promising postfire restoration measures include retention of large trees, rehabilitation of firelines and roads, and, in some cases, planting of native species. The following practices are generally inconsistent with efforts to restore ecosystem functions after fire: seeding exotic species, livestock grazing, placement of physical structures in and near stream channels, ground-based postfire logging, removal of large trees, and road construction. Practices that adversely affect soil integrity, persistence or recovery of native species, riparian functions, or water quality generally impede ecological recovery after fire. Although research provides a basis for evaluating the efficacy of postfire treatments, there is a continuing need to increase our understanding of the effects of such treatments within the context of societal and ecological goals for forested public lands of the western United States.     

Status of Marine Mammals in the United States

Abstract: The 1994 amendments to the U.S. Marine Mammal Protection Act required, for the first time, an assessment of the status of every marine mammal stock in the United States. We draw conclusions about the status of marine mammals from assessments of 153 stocks conducted to meet the requirements of these amendments. We found important regional differences in the status of stocks. Most stocks in the Atlantic and Pacific experience human-induced mortality (takes), primarily from gill-net fisheries. The proportion of stocks with takes was lower in the Gulf of Mexico and Hawaii, areas with few gill-net fisheries. Estimated takes exceeded removal limits for 29% of stocks in the Atlantic, 14% in the Pacific, 8% in Alaska, 7% in the Gulf of Mexico, and 0% in Hawaii. Twenty-eight stocks are listed as threatened or endangered under the U.S. Endangered Species Act. Most, but not all, baleen whale stocks are recovering after cessation of commercial harvests. Many species of pelagic cetaceans, including beaked and sperm whales, are vulnerable to mortality in pelagic drift-net fisheries. Most pinniped stocks experience takes, but none of these takes exceeds removal limits, and all pinniped stocks on mainland coasts of the United States are increasing in abundance. Quantitative data on trends in abundance are available for few cetacean stocks, emphasizing the difficulty of monitoring trends in these species. These stock assessments have greatly advanced our understanding of the status of marine mammals in the United States, but information gaps remain, particularly regarding stock structure and possible mortality in unmonitored fisheries.     

Status of Species Conservation Banking in the United States

Abstract:  Receiving financial gains for protecting habitat may be necessary to proactively protect endangered species in the United States. Species conservation banking, the creation and trading of "credits" that represent biodiversity values on private land, is nearly a decade old. We detail the biological, financial, and political experience of conservation banking in the United States. We contacted agencies, nongovernmental organizations, and bank owners and compiled comprehensive accounts of the experiences of current banks. There are 76 properties identified as conservation banks in the United States, but only 35 of these are established under a conservation banking agreement approved by the U.S. Fish and Wildlife Service (USFWS). The 35 official conservation banks cumulatively cover 15,987 ha and shelter a range of biodiversity, including more than 22 species listed under the U.S. Endangered Species Act. Financial motives drove the establishment of 91% of conservation banks, and the majority of for-profit banks are breaking even or making money. With credit prices ranging from $3,000 to $125,000/0.41 ha (1 acre), banking agreements offer financial incentives that compete with development and provide a business-based argument for conserving habitat. Although the bureaucracy of establishing an agreement with the USFWS was burdensome, 63% of bank owners reported they would set up another agreement given the appropriate opportunity. Increasing information sharing, decreasing the time to establish agreements (currently averaging 2.18 years), and reducing bureaucratic challenges can further increase the amount of private property voluntarily committed to banking. Although many ecological uncertainties remain, conservation banking offers at least a partial solution to the conservation versus development conflict over biodiversity.     

热带亚热带土壤氮素反硝化研究进展

热带亚热带独特的土壤性质可能使得反硝化机理有别于温带土壤.文章综述了热带亚热带地区土壤氮素生物反硝化的研究进展,试图更好地了解该地区土壤反硝化在全球氮（N）循环以及在全球环境变化和生态系统响应互作中的角色.热带亚热带土壤反硝化强度普遍较温带地区弱,且随着土地利用方式和耕作管理措施的不同而呈现较大的时空变异性.影响土壤水分状况和土壤碳（C）、N 转化特性和速率的因素即为区域和农田尺度上的反硝化影响因素.湿润型热带亚热带土壤由于含有丰富的氧化物而致使土壤氧化还原势较高,这也是导致该地区土壤反硝化势较温带地区较低的关键土壤因素之-.然而土壤pH 值不是该地区土壤反硝化势较低的主要限制因素.有机C 矿化过程较土壤全氮含量和土壤C/N 比在决定湿润型亚热带土壤反硝化势方面更为重要.愈来愈多的证据表明热带亚热带土壤反硝化的生态环境效应不同于温带地区,热带亚热带地区土壤反硝化对全球变暖的贡献应综合考虑其对其它温室气体（如CH4,CO2）排放和氮沉降的影响.热带亚热带土壤生态系统具有-些防止土壤氮素反硝化损失的机制和保氮策略.然而,热带亚热带生态系统对全球变化的响应机制及其生物地球化学调控机制仍然不清楚,这些研究对于反硝化和其它同时发生的氮转化过程模型的精确构建至关重要.     

Importance of Roadless Areas in Biodiversity Conservation in Forested Ecosystems: Case Study of the Klamath-Siskiyou Ecoregion of the United States

Abstract: Although many roadless areas on federal lands have been mapped in the United States since the 1970s, there has been little specific research on how and to what degree roadless areas contribute to biodiversity conservation. We examined the ecological attributes of mapped roadless areas for the Klamath-Siskiyou ecoregion of northwestern California and southwestern Oregon (U.S.A.). Attributes examined include special elements (such as natural heritage, serpentine geology, late-seral forests, Port Orford cedar [ Chamaecyparis lawsoniana ] ), and key watersheds; elevation and habitat representation; and overall landscape connectivity. We compared designated wilderness to roadless areas, giving special attention to the relative importance of small roadless areas (405–2024 ha). We mapped nearly 500 roadless areas of ≥405 ha. Roadless areas occupied more than twice the land area of wilderness (approximately 27% of the entire ecoregion) and contained approximately 36% of the known occurrences of heritage elements, 37% of the mapped serpentine habitats, 36% of the remaining late-seral forests, 60% of Port Orford cedar strongholds, and 42% of key watersheds for aquatic biodiversity. In addition, roadless areas were composed of significant amounts of low- and mid-elevation sites and a substantial number of the 214 mapped physical-biological habitat types with strong complementarity with designated wilderness. Fragmentation analyses showed that roadless areas contributed to regional connectivity in important ways. Also, small roadless areas were an important component of the roadless-areas conservation assessment. For the Klamath-Siskiyou ecoregion, roadless areas and designated wilderness provide an important foundation upon which to develop a comprehensive regional conservation strategy.     

农药对陆生生物的生态毒性及风险评估

农药的使用会对非靶标生物造成影响,由此世界各国都采取了风险控制手段以预防农药造成的生态危害。本文综述了欧洲、美国和日本针对农药开展的陆生生态系统风险评估方法,包括陆生非靶标生物、风险评估模型、风险评估的基本方法及生态毒性的评价指标。同时分析了农药登记管理对陆生生生物的生态毒性及风险评估中存在的科学问题,且提出了方法学的发展方向。     

A synthesis of current knowledge on forests and carbon storage in the United States

Using forests to mitigate climate change has gained much interest in science and policy discussions. We examine the evidence for carbon benefits, environmental and monetary costs, risks and trade-offs for a variety of activities in three general strategies: (1) land use change to increase forest area (afforestation) and avoid deforestation; (2) carbon management in existing forests; and (3) the use of wood as biomass energy, in place of other building materials, or in wood products for carbon storage. We found that many strategies can increase forest sector carbon mitigation above the current 162-256 Tg C/yr, and that many strategies have co-benefits such as biodiversity, water, and economic opportunities. Each strategy also has trade-offs, risks, and uncertainties including possible leakage, permanence, disturbances, and climate change effects. Because approximately 60% of the carbon lost through deforestation and harvesting from 1700 to 1935 has not yet been recovered and because some strategies store carbon in forest products or use biomass energy, the biological potential for forest sector carbon mitigation is large. Several studies suggest that using these strategies could offset as much as 10-20% of current U.S. fossil fuel emissions. To obtain such large offsets in the United States would require a combination of afforesting up to one-third of cropland or pastureland, using the equivalent of about one-half of the gross annual forest growth for biomass energy, or implementing more intensive management to increase forest growth on one-third of forestland. Such large offsets would require substantial trade-offs, such as lower agricultural production and non-carbon ecosystem services from forests. The effectiveness of activities could be diluted by negative leakage effects and increasing disturbance regimes. Because forest carbon loss contributes to increasing climate risk and because climate change may impede regeneration following disturbance, avoiding deforestation and promoting regeneration after disturbance should receive high priority as policy considerations. Policies to encourage programs or projects that influence forest carbon sequestration and offset fossil fuel emissions should also consider major items such as leakage, the cyclical nature of forest growth and regrowth, and the extensive demand for and movement of forest products globally, and other greenhouse gas effects, such as methane and nitrous oxide emissions, and recognize other environmental benefits of forests, such as biodiversity, nutrient management, and watershed protection. Activities that contribute to helping forests adapt to the effects of climate change, and which also complement forest carbon storage strategies, would be prudent.     

Assessment of forest fire vulnerability zones in Missouri,United States of America

Forest fire is one of the major disasters that distresses the terrestrial environment and causes economic disruptions for people and communities in areas prone to forest fire. Information on forest fire risk zones is therefore essential for effective and sound decision-making in forest management. Forest fire risk assessment is a critical part and the most important step in forest management because it enables us to know where the risk is higher in order to minimize threats to life, property and natural resources. This study used a hazard assessment model to assess forest fire risk in Missouri based on several measurable environmental parameters influencing forest fire risk vulnerability. Using the four ecological zones in Missouri as the basis of analysis, three forest risk zones were identified. These were high forest fire risk zones, moderate forest fire risk zone and low forest fire risk zone. Strategies for the mitigation of the hazard of forest fire in the state were also recommended.     

Potential Effects of Ongoing and Proposed Hydropower Development on Terrestrial Biological Diversity in the Indian Himalaya

Indian Himalayan basins are earmarked for widespread dam building, but aggregate effects of these dams on terrestrial ecosystems are unknown. We mapped distribution of 292 dams (under construction and proposed) and projected effects of these dams on terrestrial ecosystems under different scenarios of land‐cover loss. We analyzed land‐cover data of the Himalayan valleys, where dams are located. We estimated dam density on fifth‐ through seventh‐order rivers and compared these estimates with current global figures. We used a species–area relation model (SAR) to predict short‐ and long‐term species extinctions driven by deforestation. We used scatter plots and correlation studies to analyze distribution patterns of species and dams and to reveal potential overlap between species‐rich areas and dam sites. We investigated effects of disturbance on community structure of undisturbed forests. Nearly 90% of Indian Himalayan valleys would be affected by dam building and 27% of these dams would affect dense forests. Our model projected that 54,117 ha of forests would be submerged and 114,361 ha would be damaged by dam‐related activities. A dam density of 0.3247/1000 km² would be nearly 62 times greater than current average global figures; the average of 1 dam for every 32 km of river channel would be 1.5 times higher than figures reported for U.S. rivers. Our results show that most dams would be located in species‐rich areas of the Himalaya. The SAR model projected that by 2025, deforestation due to dam building would likely result in extinction of 22 angiosperm and 7 vertebrate taxa. Disturbance due to dam building would likely reduce tree species richness by 35%, tree density by 42%, and tree basal cover by 30% in dense forests. These results, combined with relatively weak national environmental impact assessment and implementation, point toward significant loss of species if all proposed dams in the Indian Himalaya are constructed. Efectos Potenciales del Desarrollo Hidroeléctrico Actual y Propuesto sobre la Diversidad Biológica Terrestre en el Himalaya Hindú     

Terrestrial Buffer Zones and Wetland Conservation: A Case Study of Freshwater Turtles in a Carolina Bay

Because freshwater wetlands often support diverse and unique species assemblages, wetland loss is a primary concern in biological conservation. U. S. federal statutes protect many wetlands by deterring development within delineated borders that segregate wetland habitats from upland regions. In addition, some state and local jurisdictions mandate buffer zones that afford varying levels of protection to upland habitats adjacent to wetlands. We used geographic information system analysis to test the adequacy of federal and state wetland protection statutes by determining the degree to which protected acreage encompassed the habitats freshwater turtles needed to complete their life cycles. Two critical life-cycle stages, nesting and terrestrial hibernation, occurred exclusively beyond wetland boundaries delineated under federal guidelines. The most stringent state buffer zone insulated 44% of nest and hibernation sites. Our data indicate that the freshwater turtles examined in this study required a 275-m upland buffer zone to protect 100% of the nest and hibernation sites. Insulating 90% of the sites required a 73-m buffer zone. We suggest that the habitat needs of freshwater turtles demonstrate the dependence of wetland biodiversity on the preservation of adequate amounts of upland habitats adjacent to wetlands.     

A Diverse and Endangered Aquatic Ecosystem of the Southeast United States

We document the biodiversity and conservation status of an extraordinarily diverse and endangered ecosystem in the United States that has failed to attract the same attention as tropical ecosystems—the rivers and streams of Alabama and adjoining states. Relative to North America as a whole, Alabama is a highlight of aquatic diversity supporting 38% of native fresh water fishes, 43% of native freshwater gill-breathing snails, 60% of native mussels, and 52% of native freshwater turtles. Of these, 41%, 77%, 34%, and 22% of the fishes, snails, mussels, and turtles, respectively, are endemic to Alabama and an adjacent state. Like many tropical systems of developing nations, this fauna is in an imperiled state, with 10%, 65%, 69%, and 43% of Alabama's fishes, gill-breathing snails, mussels, and turtles, respectively, considered either extinct, endangered, threatened, or of special concern. Unlike tropical systems, however, little effort has been made to protect the taxa and their habitats. Only 40% of fishes, 1% of gill-breathing snails, 32% of mussels, and 20% of freshwater turtles are formally listed as either threatened or endangered via the U.S. Endangered Species Act of 1973; no critical habitat has been protected. Clearly, the biodiversity crisis in not limited to tropical systems of developing nations. Although the Endangered Species Act of 1973 helps to ensure a future of sustainable diversity, efforts must be made to hasten recognition, protection, and recovery of critical habitat, particularly for hotspots such as the aquatic systems of Alabama.     

A simple economic model of endangered species preservation in the United States

Concern for the acceleration in threats to species diversity in the United States led to the passage of the Endangered Species Act of 1973. In this paper, this legislation is examined in an economic context. A simple model is developed where management and constraints on economic activity are substitutes in the production of species stocks. Whether economic growth constraints (the primary policy tool of the 1973 Act) are justified for preservation purposes depends on technical substitution possibilities, relative cost ratios, and the existence of budget constraints for species management. Since the same combination of these factors will not occur for all species, it is argued that more flexibility in endangered species policy may preserve the same levels of species stocks at lower costs to society.     

Legislating soil reconstruction on surface-mined land in the United States

The author, who participated with an interdepartmental team in advising the US Congress in writing the Surface Mining Control and Reclamation Act, outlines the often conflicting requirements which determined the genesis of the Act. The paper also discusses the criteria for judging the effectiveness of restoring soil productivity and the emphasis on the restoration of prime farmland. It also notes that the nature of the balance between environmental protection, farmland productivity and the needs of coal are still uncertain and that there is a contradiction in US attempts to alleviate hunger while national soil resources are being destroyed.From 1972 to 1977, the author participated with an interdepartmental tcam that assisted the U.S., Congress in writing the Surface Mining Control and Reelamation Act.     

Vascular plant extinction in the continental United States and Canada

Extinction rates are expected to increase during the Anthropocene. Current extinction rates of plants and many animals remain unknown. We quantified extinctions among the vascular flora of the continental United States and Canada since European settlement. We compiled data on apparently extinct species by querying plant conservation databases, searching the literature, and vetting the resulting list with botanical experts. Because taxonomic opinion varies widely, we developed an index of taxonomic uncertainty (ITU). The ITU ranges from A to F, with A indicating unanimous taxonomic recognition and F indicating taxonomic recognition by only a single author. The ITU allowed us to rigorously evaluate extinction rates. Our data suggest that 51 species and 14 infraspecific taxa, representing 33 families and 49 genera of vascular plants, have become extinct in our study area since European settlement. Seven of these taxa exist in cultivation but are extinct in the wild. Most extinctions occurred in the west, but this outcome may reflect the timing of botanical exploration relative to settlement. Sixty-four percent of extinct plants were single-site endemics, and many occurred outside recognized biodiversity hotspots. Given the paucity of plant surveys in many areas, particularly prior to European settlement, the actual extinction rate of vascular plants is undoubtedly much higher than indicated here.     

Species Imperilment and Spatial Patterns of Development in the United States

Abstract:  Conservation biologists and others hypothesize that humankind's "ecological footprint" is affected not only by the sheer intensity of human activity but also by its spatial arrangement. We used a multivariate statistical model and state-level data to evaluate correlations between species imperilment and the level and spatial distribution of human settlement and infrastructure development in the United States. The level of human activity—measured by the number of people and households, incidence of roads, and intensity of nighttime lights—was significantly correlated with the ecological imperilment of species. Our regression models consistently showed that a 1% increase in the level of human activity across the United States was associated with about a 0.25% increase in the proportion of plant and animal species considered at risk of extinction by The Nature Conservancy. The distribution of human activity did not affect species imperilment. Our results point to rising levels of human activity—and not some particular (e.g., sprawling) distribution of human activity—as the most relevant anthropogenic factor explaining biodiversity loss in the United States.     

Forecasting the Expansion of Zebra Mussels in the United States

Abstract:  Because zebra mussels spread rapidly throughout the eastern United States in the late 1980s and early 1990s, their spread to the western United States has been expected. Overland dispersal into inland lakes and reservoirs, however, has occurred at a much slower rate than earlier spread via connected, navigable waterways. We forecasted the potential western spread of zebra mussels by predicting the overland movement of recreational boaters with a production-constrained gravity model. We also predicted the potential abundance of zebra mussels in two western reservoirs by comparing their water chemistry characteristics with those of water bodies with known abundances of zebra mussels. Most boats coming from waters infested with zebra mussels were taken to areas that already had zebra mussels, but a small proportion of such boats did travel west of the 100th meridian. If zebra mussels do establish in western U.S. water bodies, we predict that population densities could achieve similar levels to those in the Midwestern United States, where zebra mussels have caused considerable economic and ecological impacts. Our analyses suggest that the dispersal of zebra mussels to the western United States is an event of low probability but potentially high impact on native biodiversity and human infrastructure. Combining these results with economic analyses could help determine appropriate investment levels in prevention and control strategies .