TIMBER HARVESTING AND THE HYDROLOGIC RESPONSE OF REDWOOD CREEK,CALIFORNIA

Timber removal on publicand private land surrounding Redwood National Park exacerbates naturally high rates of erosion that are common to this region and alters hydrologic processes within the park boundaries. These alterations of the natural environment complicate the efforts of the National Park Service to preserve a remnant of the once extensive coastal redwood ecosystem in the park. A watershed model for Redwood Creek calibrated to pre-logging conditions is employed to define and quantify changes in the hydrologic response of the basin during the years when timber harvesting reduced significantly the acreage of redwoods. Analysis of modeled and observed runoff indicates that timber removal is related to increased runoff during wet months and wet years, but runoff is reduced during dry months and dry years. These alterations in the hydrologic system occur at the least beneficial time because they augment high flows, whereas low flows are depleted. Such changes in runoff contribute to magnified erosion and deposition problems and increased stress for the flora and fauna that reside in and along Redwood Creek. [Key words: Redwood National Park, hydrology, watershed model, timber harvesting.]     

Greening U.S. National Parks: Expanding Traditional Roles to Address Climate Change

The U.S. National Park Service has embarked on a new campaign to address climate change. This directive includes new programs to encourage visitors to change their behaviors once they return home. By becoming involved in issues that go beyond park boundaries, these changes mark a shift in how the National Park Service fulfills its mission. This article explores how these efforts evolved and the possible implications to the visitors being exposed to a new message. Visitors were surveyed in Denali National Park and Preserve in Alaska. The results revealed that the majority of those surveyed support these new efforts by the National Park Service.     

Lasting Legacies: Conservation and Communities at Huascaran National Park,Peru

This article uses a case-study approach to investigate the challenges of protected area (PA) management for Huascaran National Park in the Peruvian Andes. The park is analyzed by situating the timing of establishment of the park boundaries within the context of two historical Peruvian events: agrarian reform (1969) and an earthquake (1970). Interviews and narratives from community members and stakeholders associated with park delimitation and management were used for the study. Analysis of narratives revealed that the establishment of park boundaries, the legal definition used for the park, and land use restrictions contribute to diminished support for the park from surrounding communities. Community and national institutions negotiate the spatial boundary of conservation in Huascaran National Park while engaging with historical narratives that invoke environmental constraints and acts of resistance.     

不同数据源下毛乌素沙地风况及输沙势特征

风是干旱、半干旱区风蚀风积地貌发育的动力基础,我们通常使用风速资料探讨区域风况,但选取不同的风速资料研究同一区域风况时结果存在差异。以毛乌素沙地为例,分别选取中国气象数据网（CMDC）的日最大风速及风向与美国国家气候数据中心（NCDC）的日8个定时观测风速及风向,对比分析起沙风特征。结果表明：（1）毛乌素沙地平均起沙风速相差较小,但起沙风频率明显在CMDC数据源中较高;（2）毛乌素沙地年起沙风向均以WNW、W和NW为主,但年起沙风次风向、不同区域夏季和秋季起沙风次风向组成均在CMDC数据源中较复杂,且起沙风主次风向频率均在CMDC数据源中较高;（3）毛乌素沙地整体均属于低风能环境,中等风向变率,锐双峰或宽单峰风况,但以最大风速计算的年输沙势约是以定时观测风速计算结果的3.3倍。基于两套数据源定量对比分析毛乌素沙地风况及输沙势,这对区域风况研究是一种新的尝试,以期提高对不同数据源提供的风速差异的认识,为今后不同区域的起沙风分析提供一定的参考。     

Cyclic and Seasonal Beach Response: A Comparison of Oceanside and Bayside Beaches

This study compares the cyclic and seasonal geomorphic responses of oceanside and bayside beaches on Sandy Hook Spit, New Jersey. It was hypothesized that the different nature of onshore wind regimes at bayside and oceanside beaches would cause different types of beach change. On the east-facing ocean shoreline, rates of beach change are related to weather patterns associated with the passage of mid-latitude cyclonic storms. Bayside beach change is related to the influence of the prevailing westerlies. Storm erosion and post-storm deposition is more rapid on oceanside beaches. Swell waves occurring between storms rapidly reinstate pre-storm equilibrium conditions. Lower bay-side wave energies occurring between storms have little effect on profile development, and foreshore slopes inherited from previous storms undergo little change. Bayside beaches therefore appear to be more in equilibrium with storm conditions than oceanside beaches.

Changes in foreshore slope, beach volume, and beach position associated with individual storm events are compared to seasonal trends to test the applicability of the Hayes cyclic model of beach development to both oceanside and bayside beaches. There is evidence of a cyclic trend of develop-ment on the more exposed ocean sites and seasonal development on the more sheltered bayside sites, which suggests that cyclic development may be causally related to the difference among the energy levels of the storm and nonstorm wave regimes.     

内蒙古浑善达克沙地南缘 137Cs、 210Pbex复合示踪研究

土壤风蚀是导致土地退化、荒漠化以及大气扬尘、风沙天气的重要原因。内蒙古浑善达克沙地南缘是国家主体功能区规划确定的“两屏三带”的重要部分,科学估算本地区土壤风蚀强度及其变化,是地区生态安全和生态建设成效评估的重要内容。选择浑善达克沙地南缘的正蓝旗为研究区,运用 ¹³⁷Cs、 ²¹⁰Pb_ex复合示踪技术,对研究区土壤侵蚀速率及其变化进行了分析。结果表明：① 研究区内 ¹³⁷Cs本底值为2123.5±163.94 Bq·m ^-2, ²¹⁰Pb_ex本底值为8112±1787.62 Bq·m ^-2。② 基于 ¹³⁷Cs同位素示踪分析,研究区侵蚀模数为-483.99~740.31 t·km ^-2·a ^-1;基于 ²¹⁰Pb_ex同位素示踪分析,研究区侵蚀模数为-441.53~797.98 t·km ^-2·a ^-1。③ 与20世纪20-70年代相比,20世纪70年代以来土壤侵蚀与堆积速率明显降低,研究区风沙活动明显减弱,区域生态环境质量得到改善。综合 ¹³⁷Cs和 ²¹⁰Pb_ex的多同位素复合示踪技术在干旱、半干旱地区土壤侵蚀研究中具有较大的潜力。     

A geographical information system to facilitate military housing management

Abstract

The Department of the Army must provide its personnel with acceptable housing at minimum cost within the vicinity of military installations. To achieve these housing objectives, the Army often has to enter into agreements for the long-term leasing of existing housing. A decision-support system, called HANS, has been developed to project the number of leases that must be arranged.

This paper describes a geographical information system (GIS) enhancement that helps Army managers to locate the lease properties and display characteristics of the properties. It also overviews the benefits, challenges, and limitations of the enhanced system.     

Improving National Park Service and Nonprofit Partnerships—Lessons from the National Trail System

Federal land management agencies are increasingly relying on collaborative partnerships for managing national trails, heritage areas, scenic rivers, and recreation areas. For agencies such as the National Park Service, these joint approaches are significantly different from traditional management approaches. This article uses a case study of the Juan Bautista De Anza National Historic Trail to identify partnership lessons for this case and other protected areas that rely on public–private partnerships. The research highlights partnership issues with nonprofit capacity and mission alignment, project momentum, and leadership dilemmas. We suggest that agencies such as the National Park Service need to assess the mission and capacity of community and nonprofit groups to determine their partnership approach. This is a significant shift, from agencies simply needing to find organizations willing to partner on collaborative management efforts, to a role in assessing, forming, and developing nonprofit partners.     

近40 a毛乌素沙地荒漠化过程研究

毛乌素沙地位于我国北方农牧交错带上,生态环境具有较强的敏感性和脆弱性。采用1977-2010年Landsat数据,运用决策树和非监督分类相结合的方法对近40 a来毛乌素沙地荒漠化过程进行了研究。结果表明：（1）决策树分类和ISODATA非监督分类相结合可快速实现荒漠化地区地物遥感解译,图像总分类精度大于87.28%;（2）近40 a毛乌素沙地流动沙地面积在20世纪90年代末最大,2010年最小;半固定沙地面积在2010年最大,90年代末最小;固定沙地面积在2010年最大,70年代末最小;（3）70年代末荒漠化程度最为严重,流动和半固定沙地面积之和占了毛乌素沙地总面积83.64%;80年代末、90年代末和2010年的流动和半固定沙地面积之和分别占总面积74.51%、77.10%和67.90%;（4）流动沙地、半固定沙地、固定沙地、耕地和水体间的相互转换过程活跃,荒漠化演替过程显著区在70年代末到80年代末主要分布在北部、西北部和南部,80年代末到90年代末主要分布在西部和南部,90年代末到2010年主要分布在西北部、西部、南部和东北部;（5）近40 a毛乌素沙地气温以0.039 ℃/a的平均速度递增,降水则以0.095 mm/a的平均速度递减,气候总体上体现出暖干的趋势。降水是影响荒漠化过程的重要因素,但不是唯一原因,人文因素中的人口、土地利用结构和政策实施等也是影响荒漠化过程重要因素。     

Paleolimnological reconstruction of recent acidity changes in four Sierra Nevada lakes

We have completed a paleolimnological analysis of sediment cores from four lakes in the Sierra Nevada Range of California (USA). The diatom-inferred pH profile from Harriet Lake in Yosemite National Park (present pH=6.52) indicates no significant trends over the last 250 years. Inferred pH from Emerald Lake in Sequoia National Park (present pH=6.10) indicates a very small increase (<0.1 pH unit) over the past 60 years and perhaps another small increase (ca. 0.15 pH unit) since 1976. Eastern Brook Lake in Inyo National Forest (present pH=7.06) shows evidence of both long-term alkalinification (ca. 0.3 pH unit over the last 200 years) and pH fluctuations since 1970. Lake 45 in King's Canyon National Park (present pH=5.16) appears to have acidified slightly (ca. 0.2 pH unit) over the last 60 years. Factors causing the observed trends are uncertain, but a role for acidic deposition cannot be ruled out.     

Holocene vegetation history of Bundjalung National Park and Bungawalbin Creek,north‐eastern New South Wales

Few studies have been conducted into the environmental history of the North Coast region of New South Wales (NSW). To address this, two sedimentary sequences located in the coastal Bundjalung National Park and at Bungawalbin Creek, just north of the Park (both near Evans Head, NSW) have been investigated. Palynological and geochemical analyses were used to reconstruct the history of the sites. Fossil pollen evidence representing much of the Holocene period — basal radiocarbon dates of 8700 ± 60 years BP and 6600 ± 60 years BP are available from the Bundjalung National Park and Bungawalbin Creek sites, respectively — indicates a dynamic past environment, with an overall tendency towards drier conditions. This evidence is supported, in part, by charcoal analyses indicating an increase in the occurrence of fire over time. Chemical analyses of the sediments indicate that the Bungawalbin site was strongly influenced by estuarine conditions, whereas the Bundjalung National Park site was only influenced indirectly by estuarine conditions.     

近50年来毛乌素沙地的沙漠化过程研究

根据野外考察、应用遥感和地理信息系统技术对毛乌素沙地进行动态研究表明，50年代沙漠化土地面积约为12900km^2，到了70年代中期达41110km^2,80年代后期，减少为32590km^2，至1993年又下降到了30650km^2。50-70年代是沙漠化土地迅速发展的时期，而进入80年代以后，总体上是处于逆转过程中，已有近9460km^2的沙漠化土地得到了治理，这主要得益于“三北”防护林工程的实施和当地政府与干部群众积极开展沙漠化防治的努力，也进一步证明了：沙漠化主要是人类造成的，也只有人类能够控制它。     

Resident Willingness to Pay for Ecotourism Resources and Associated Factors in Sanjiangyuan National Park,China

Willingness to Pay (WTP), Willingness to Work (WTW) and Willingness to Accept Compensation (WTA) are the three quantitative criteria for assessing local ecological asset values for the social aspects of ecosystem services and residents’ willingness to contribute to and receive compensation for tourism ecology. The objectives of this study are to estimate the residents’ willingness to pay, work and accept compensation for conservation at Sanjiangyuan National Park, and to analyze the relationship between residents’ attitude towards tourism ecology and the ecological assets of the National Park based on a standard questionnaire survey. The dichotomous choice Contingent Valuation Method (CVM) was employed to determine the willingness. The survey conducted in 2018 collected WTP, WTW, WTA, socio-demFographical information, social trust and resident perceptions toward tourism impacts and relevant management strategies from 244 residents in two counties. Based on generalized linear modeling, income and education level are important for residents’ WTP and WTA, but other social characteristics, such as gender and age, do not have significant effects. The social trust is found to be a significant factor on residents’ willingness, despite the limitation on education level. Also, government funding is associated with residents’ inclination to WTP, WTW and WTA, but the support levels differ among the two counties due to geographical and social heterogeneities. The estimated WTP, WTW and WTA for the Sanjiangyuan National Park in 2018 were 1.2448×10 ⁷ yuan, 1.247×10 ⁶ hours and 2.3232×10 ⁷ yuan yr ^-1 based on the survey and published demographics. This study, for the first time, estimates the WTP, WTW and WTA for the Sanjiangyuan National Park and informs ecological conservation managers and policy makers. Ultimately, to maintain the long-term benefits arising from sustainable development, compensation should be specifically tailored and site-dependent, and development measures based on local resources should be adopted by governments to actively support eco-tourism activities.     

大堡礁海洋公园与澳大利亚海洋保护区建设

为保护大堡礁独特的生态系统,澳大利亚制定多部法案,启动"大堡礁滨海湿地保护项目"。健全的多功能分区保护制度、可操作性较强的环境管理费征收制度和独具特色的船舶管理措施,已成为大堡礁海洋公园管理中的亮点。2012年6月,澳大利亚联邦政府宣布计划建成全球最大的海洋保护区,这是进一步加强大堡礁海洋公园管理的机遇。     

PARTNERSHIPS AND PHOTOGRAPHS: COMMUNITY CONCEPTIONS OF KEWEENAW NATIONAL HISTORICAL PARK*

Geographers have a long tradition of using photographs to investigate landscape meaning. I conducted photo‐elicitation research with community members residing in and around one of the National Park Service (nps ) “partnership parks” in order to obtain their conceptions of the park. The nps partners with myriad groups in order to manage the park, resulting in mostly privatized amenities at Michigan's Keweenaw National Historical Park. Participants in my study took photographs of landscapes and used them to discuss their conceptions of the park. Building upon recent scholarship on the perceptions of parks and place attachment in parks, the photo‐elicitation revealed a strikingly complex array of understandings. Social class, not whether one lived within or outside the park's boundaries, was the most important variable in categorizing perceptions of the park. These data help us understand how community members conceive of partnership parks and thus may help inform nps decision making.     

松嫩沙地的形成与环境变迁

松嫩沙地是由下伏冲积砂经风力吹扬、堆积而形成的, 风成砂既是具风成特点, 又保留冲积特征。自全新世形成以来, 沙地曾经历了4次固定时期和4次扩张时期。松嫩平原西部在9000年以前气候较为干旱, 自然环境为荒漠、半荒漠; 9000年-7000年, 气候为半干旱, 自然环境演变为蒿类草原或稀树蒿类草原; 距今7000年以来经历了3次干旱期、2次半干旱期和1次半湿润期; 距今1000年以来, 气候又呈变干趋势。     

东部沙区表土有机质和速效养分与风沙环境关系初探

东部沙区表土有机质、速效养分含量普遍较低。按照库布齐沙漠、毛乌素沙地、浑善达克沙地、科尔沁沙地和呼伦贝尔沙地的次序,有机质和速效K含量逐渐增大,这种分布格局与区域风沙环境性质、风沙活动方式密切相关;各沙漠/沙地内部,表土有机质和速效K含量分别与植被盖度、颗粒平均粒径、分选系数之间存在较好的相关性。速效N和速效P含量未表现出上述变化规律。可见有机质和速效K含量对风沙环境的变化较为敏感,因而其在表土中的再分配可以在一定程度上反映局地风沙环境的变化,而速效N和速效P对风沙环境的指示意义不明显。东部沙区表土有机质、速效N及速效P含量普遍高于西部沙区,而速效K含量明显偏低。     

近20 a黄河源园区土地退化时空演化分析

三江源黄河源园区作为黄河的发源地,它的生态系统对整个黄河流域至关重要。针对研究区2000—2020年存在的土地退化问题,选取土壤侵蚀模数、沙化特征指数与土壤湿度指数,采用空间托普利茨逆协方差聚类法开展了3个参数的聚类分析,从而进行黄河源园区土地退化时空演化分析,并采用极致梯度提升法进行时空演化影响因素分析。结果表明：（1） 土地退化现象最严重的地区是中部偏南地区与东北地区,其次为偏北地区。（2） 东北地区存在水土流失与土地沙化2种问题,中部偏南地区以严重的水土流失为主,偏北地区主要表现为土地沙化问题。（3） 近20 a来,土地退化指数呈现波动性下降,土地退化整体趋于好转,在偏南地区表现得更明显。（4） 水土流失问题整体好转,偏北地区有土地沙化的风险。该研究对掌握黄河源园区土地退化的时空分布及发展趋势、推进黄河源园区生态保护具有重要意义。     

Processes reshaping the Nile delta promontories of Egypt: pre- and post-protection

Shoreline positions established from beach profile surveys combined with wave data are jointly analyzed, as a function of their contribution to coastal processes, to investigate the interaction between waves, shoreline orientation and coastal structures along the Nile delta promontories, Rosetta, Burullus and Damietta. Repeated beach profile surveys along the promontory sectors (64 km long in total) have been analyzed to determine rates of shoreline changes prior to construction (1971–1990) and after construction of protective structures (1990–2000). The behavior of coastline pre- and post-construction indicates that coastal erosion fronting protective structures has declined in the case of the seawalls at the tips of the Rosetta and Damietta promontories, or has been partially replaced by sand accumulation in the case of detached breakwaters at Baltim (east of Burullus promontory) and at Ras El Bar (west of the Damietta promontory). As a consequence, downdrift erosion has been initiated in local areas adjacent to these structures in the direction of longshore sediment transport. The 5-km-long seawall protecting the Rosetta promontory has stopped the dramatic erosion of this highly eroded area (formerly shoreward retreated 88 m/year), with adverse local erosion at its west and east ends, being 3 and 13 m/year, respectively. Similarly, the 6-km-long seawall built on the eastern tip of the Damietta Promontory, still under construction, has nearly stopped the severe erosion, which was formerly 10 m/year. The detached breakwaters at both Baltim and at Ras El Bar have accumulated sand at accretion rates of 37 and 14 m/year, respectively. This sand accumulation is associated with downdrift erosion of 25 and 13 m/year at Baltim and Ras El Bar, respectively. Results reaffirm that the original erosion/accretion patterns along the Nile delta promontories have been reshaped due to the massive protective structures built during the last decade. This reshaping along the examined promontories is generally controlled by the temporal variability in the intensity and reversibility of wave directions and associated longshore currents, coastline orientation and by the existing coastal protection structures.     

经济形态演变对海洋海岛生态环境的影响——以美国海峡群岛为例

海洋海岛生态环境脆弱,一旦遭受破坏难以修复。人类社会历经原始经济时代、农业经济时代、工业经济时代和知识经济时代,经济形态的演变影响着人类生存的生态环境。以美国海峡群岛为例,以时间和事件两个维度对海岛生态环境破坏、生态修复和环境保护进行梳理,侧重于知识经济时代在国家公园管理局管理下的生态修复和环境保护。其中信息知识、生态文明、高新技术是海峡群岛实现生态回归的重要因素。海峡群岛的发展历程和后期的生态修复与管理为其他国家海洋海岛经济发展提供借鉴。