Precipitation Amount and Intensity Trends Across Southwest Saudi Arabia

This study examines precipitation accumulation and intensity trends across a region in southwest Saudi Arabia characterized by distinct seasonal weather patterns and mountainous terrain. The region is an example of an arid/semiarid area faced with maintaining sustainable water resources with a growing population. Annual and seasonal trends in precipitation amount were examined from 29 rain gages divided among four geographically unique regions from 1945/1946 to 2009. Two of the regions displayed significantly declining annual trends over the time series using a Mann‐Kendall test modified for autocorrelation (α < 0.05). Seasonal analysis revealed insignificant declining trends in at least two of the regions during each season. The largest and most consistent declining trends occurred during wintertime where all regions experienced negative trends. Several intensity metrics were examined in the study area from four additional stations containing daily data from 1985 to 2011. Intensity metrics included total precipitation, wet day count, simple intensity index, maximum daily annual rainfall, and upper/lower precipitation distribution changes. In general, no coherent trends were found among the daily stations suggesting precipitation is intensifying across the study area. The work represents the first of its size in the study area, and one of few in the region due to the lack of available long‐term data needed to properly examine precipitation changes.     

An interdisciplinary assessment of private conservation areas in the Western United States

Conservation easements are the fastest growing private conservation strategy in the United States. However, mechanisms to assess private land conservation as well as their support by the general public are not well understood. This study uses the ecosystem services framework for assessing existing private lands in Idaho and identifies areas for future conservation easements. Using conservation targets of the land trust as a guide for selecting ecosystem services, we (a) mapped the spatial delivery of conservation targets across public and private lands, (b) explored public awareness in terms of social importance and vulnerability, and (c) mapped future priority areas by characterizing conservation bundles. We found that public lands provided the highest levels of conservation targets, and we found no difference in conservation target provision between private areas and conservation easements. The spatial characterization of conservation target bundles identified potential future priority areas for conservation easements, which can guide planning of land trust conservation efforts.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01323-x) contains supplementary material, which is available to authorized users.     

Associations of Grassland Bird Communities with Black‐Tailed Prairie Dogs in the North American Great Plains

Colonial burrowing herbivores can modify vegetation structure, create belowground refugia, and generate landscape heterogeneity, thereby affecting the distribution and abundance of associated species. Black‐tailed prairie dogs (Cynomys ludovicianus) are such a species, and they may strongly affect the abundance and composition of grassland bird communities. We examined how prairie dog colonies in the North American Great Plains affect bird species and community composition. Areas occupied by prairie dogs, characterized by low percent cover of grass, high percent cover of bare soil, and low vegetation height and density, supported a breeding bird community that differed substantially from surrounding areas that lacked prairie dogs. Bird communities on colony sites had significantly greater densities of large‐bodied carnivores (Burrowing Owls [Athene cunicularia], Mountain Plovers, [Charadrius montanus], and Killdeer [Charadrius vociferus]) and omnivores consisting of Horned Larks (Eremophila alpestris) and McCown's Longspurs (Rhynchophanes mccownii) than bird communities off colony sites. Bird communities off colony sites were dominated by small‐bodied insectivorous sparrows (Ammodramus spp.) and omnivorous Lark Buntings (Calamospiza melanocorys), Vesper Sparrows (Pooecetes gramineus), and Lark Sparrows (Chondestes grammacus). Densities of 3 species of conservation concern and 1 game species were significantly higher on colony sites than off colony sites, and the strength of prairie dog effects was consistent across the northern Great Plains. Vegetation modification by prairie dogs sustains a diverse suite of bird species in these grasslands. Collectively, our findings and those from previous studies show that areas in the North American Great Plains with prairie dog colonies support higher densities of at least 9 vertebrate species than sites without colonies. Prairie dogs affect habitat for these species through multiple pathways, including creation of belowground refugia, supply of prey for specialized predators, modification of vegetation structure within colonies, and increased landscape heterogeneity. Asociaciones de Comunidades de Aves de Pastizales con Perros de la Pradera en la Gran Llanura de Norte América     

Effects of More Frequent and Prolonged El Niño Events on Life-History Parameters of the Degu, a Long-Lived and Slow-Reproducing Rodent

Abstract:  Global climate change (GCC) can have profound effects on species whose ecology is governed primarily by climatic factors. The ecology of small mammals inhabiting semiarid Chile is strongly affected by the El Niño Southern Oscillation (ENSO). During La Niña events in this area, dry conditions prevail and species may disappear from the thorn-scrub habitat. Conversely, El Niño events bring high rainfall, and associated pulses of food trigger small-mammal population increases. We used capture–mark–recapture to study responses of the degu ( Octodon degus ), a dominant small mammal, to variation in rainfall over 18 years. In response to a recent trend toward wetter conditions, degus reached record-high densities and maintained more stable numbers in the area. Underlying mechanisms involved variation in adult survival, juvenile persistence, and fecundity linked to rainfall changes during consecutive years (i.e., rainfall phases). During prolonged droughts, degus had low survival and produced fewer offspring, with low persistence. Following high rainfall, these parameters reversed; consecutive wet years resulted in further increases. Weak declines in fecundity and adult survival and high persistence of juveniles explained delayed responses to deteriorating conditions in initial dry years. If GCC leads to increased frequency of El Niño events, we anticipate greater numerical dominance of degus in semiarid Chile and possible range expansion. Furthermore, degus have strong impacts on other small mammal and some plant species, are important prey species, and are agricultural pests and disease reservoirs. Hence, GCC has the potential to dramatically influence their ecology in northern Chile and to have cascading effects on other components of this system.     

Protection of biota on nonpark public lands: Examples from the US Department of Energy Oak Ridge Reservation

Security buffers of Department of Defense (DoD) and Department of Energy (DOE) reservations provide long-term habitat protection for many rare and endangered species. The importance of these government-owned reservations as nationally valuable resources has been relatively unrecognized. During the last 50 years, the DOE Oak Ridge Reservation (ORR) has been a relatively protected island in a region of rapidly expanding urbanization and land clearing. Consisting of the Oak Ridge National Environmental Research Park and associated lands surrounding DOE facilities at Oak Ridge Tennessee, the unique nature of the ORR in the surrounding landscape is clearly visible from the air and has been documented using remote sensing data. Although forests dominate much of other regions of eastern Tennessee, this 15,000-ha tract of mostly natural forest habitat is unique in the southern Ridge and Valley physiographic province, which is otherwise widely developed for pasture, marginal cropland, woodlot, and urban uses. Twenty state-listed and federal-candidate plant species are known to be present on the ORR. This richness of species, which are provided protection by state and federal laws, exceeds that of the Great Smoky Mountains National Park on a species area basis and is an index of the value of the ORR both regionally and nationally in conserving biodiversity. With the end of the Cold War, changing DoD and DOE missions combined with increasing development pressure contribute to uncertainty in the future management of security reservations.     

Cooperation or conflict? Interagency relationships and the future of biodiversity for US parks and forests

Cooperation between the United States Department of Agriculture (USDA) Forest Service and the United States Department of Interior (USDI) National Park Service is most often advocated to protect biological diversity on national forests and parks, but the agencies, so far, have done little to implement the biodiversity mandates of such laws as the Endangered Species Act and the National Forest Management Act. The ideological and political history of the Forest Service and Park Service is explored to determine the roots of interagency conflicts. Several recent models of cooperative reform are also critiqued and found to be insufficient to stimulate better working relationships. To protect biodiversity, cooperation must be framed within conservation biology and must place primary emphasis on ecosystem patterns and processes as well as on individual species. Increased education of agency managers, ecosystem-level research, local and regional public participation, scientific oversight committees, new legislation, and enlightened leadership also play important roles. Ultimately, management policies must be reframed within a context of ecocentric values.     

哈尔滨市区绿地对交通噪声衰减效果研究

2007年4月6日-5月30日,采用HS-5633型数字声级仪分别对哈尔滨市区六处主要交通干道进行交通噪声测量,同时在干道周围的绿地进行对比测量,并将所得数据进行分析统计。结果表明,绿地（包括各类林地、草坪、隔离带及其不同组合）对交通噪声的衰减可达2dB（A）以上,减噪效果十分明显,减噪数值与绿地宽度和绿地植被组成有密切关系。因此,应对城市中各种类型的绿地及其组成的混合林地种植予以足够、有效的重视,如高大乔木＋灌木、常绿树＋草坪、乔木＋灌木＋草坪等配置紧凑的绿地类型,并应加大保护力度。     

矿山废弃地的生态恢复

本文通过对矿山废弃地及其恢复情况调查,分析了我国矿山废弃地生态恢复的方向及蕴藏的产业机遇。     

Wildfire Policy and Public Lands: Integrating Scientific Understanding with Social Concerns across Landscapes

Abstract:  Efforts to suppress wildfires have become increasingly problematic in recent years as costs have risen, threats to firefighter safety have escalated, and detrimental impacts to ecosystems have multiplied. Wildfires that escape initial suppression often expand into large, high-intensity summer blazes. Lost is the legacy of smaller fires that likely burned outside extreme weather and fuel conditions and resulted in less severe impacts. Despite the recognized need for modifications to existing policies and practices, resource agencies have been slow to respond. The spread of exotic species, climate change, and increasing human development in wildlands further complicates the issue. New policies are needed that integrate social and ecological needs across administrative boundaries and broad landscapes. These policies should promote a continuum of treatments with active management and reduction of fuel hazard in wildland-urban interface zones and reintroduction of fire in wildlands. Management goals should focus on restoration of the long-term ecological health of the land. Projects that reduce fuel loads but compromise the integrity of soil, water supplies, or watersheds will do more harm than good in the long run. Despite significant ecological concerns, learning to live with fire remains primarily a social issue that will require greater political leadership, agency innovation, public involvement, and community responsibility.     

Dependable Water Supplies from Valley Alluvium in Arid Regions

Reliable sources of high-quality water for domestic use are much needed in arid regions. Valley alluvium, coarse sand and gravel deposited by streams and rivers, provides an ideal storage medium for water in many regions of the world. However, river sediments will not accumulate in a valley without a natural or artificial barrier to slow the water. Sediments will deposit upstream of a barrier dam and form an alluvial deposit of relatively well-sorted material. The alluvium then acts as both an underground water-supply reservoir and a water filter, yielding a constant flow of high-quality water. Trap dams that store water in alluvial sediments and slowly release the filtered water represent an appropriate and inexpensive technology for combating desertification and mitigating the effects of drought at the community level. Small trap dams may be built as a community project using local materials and local labor.