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201.
DANIEL J. TWEDT WILLIAM B. UIHLEIN III † A. BLAINE ELLIOTT† 《Conservation biology》2006,20(1):100-110
Abstract: The historical area of bottomland hardwood forest in the Mississippi Alluvial Valley has been reduced by >75%. Agricultural production was the primary motivator for deforestation; hence, clearing deliberately targeted higher and drier sites. Remaining forests are highly fragmented and hydrologically altered, with larger forest fragments subject to greater inundation, which has negatively affected many forest bird populations. We developed a spatially explicit decision support model, based on a Partners in Flight plan for forest bird conservation, that prioritizes forest restoration to reduce forest fragmentation and increase the area of forest core (interior forest >1 km from "hostile" edge). Our primary objective was to increase the number of forest patches that harbor >2000 ha of forest core, but we also sought to increase the number and area of forest cores >5000 ha. Concurrently, we targeted restoration within local (320 km2 ) landscapes to achieve ≥60% forest cover. Finally, we emphasized restoration of higher-elevation bottomland hardwood forests in areas where restoration would not increase forest fragmentation. Reforestation of 10% of restorable land in the Mississippi Alluvial Valley (approximately 880,000 ha) targeted at priorities established by this decision support model resulted in approximately 824,000 ha of new forest core. This is more than 32 times the amount of core forest added through reforestation of randomly located fields (approximately 25,000 ha). The total area of forest core (1.6 million ha) that resulted from targeted restoration exceeded habitat objectives identified in the Partners in Flight Bird Conservation Plan and approached the area of forest core present in the 1950s. 相似文献
202.
Fine-Scale Diversity and Rarity Hotspots in Northern Forests 总被引:5,自引:0,他引:5
IVAR GJERDE§ MAGNE SÆTERSDAL JØRUND ROLSTAD† HANS H. BLOM‡ KEN OLAF STORAUNET† 《Conservation biology》2004,18(4):1032-1042
203.
Spatial analysis of habitat selection by Sitka black-tailed deer in Southeast Alaska,USA 总被引:1,自引:0,他引:1
We used a vector-based geographic information system (GIS) to examine habitat selection by radiocollared Sitka black-tailed
deer (Odocoileus hemionus sitkensis) in logged forests of southeast Alaska. Our main objective was to explain deer habitat selection relative to old-growth/clear-cut
edges and edge habitats at two different spatial scales. Deer home ranges contained higher percentages of recent clear-cuts
(50–69%) than the study area (37%;P<0.01) and had higher old-growth/clear-cut edge densities than expected by chance (P<0.01). Deer relocation points were closer to old-growth/clear-cut edges (average=135 m) than random points located within
each deer's relocation area (average=168 m;P=0.05). Likewise, deer relocations were closer to old-growth/clear-cut edges than points randomly located within old-growth
stands or recent clear-cuts (P<0.01). As the size of clear-cuts increased, both deer relocation density and the proportion of a clear-cut occupied by deer
home ranges decreased. Because old growth is important deer habitat and clear-cuts can produce deer forage for only 20–30
years after logging in southeast Alaska, deer management plans such as preserving entire watersheds and maintaining mixes
of old growth and recent clear-cut have been proposed. Our data suggest that deer need a diversity of habitats near each other
within their home ranges. 相似文献
204.
205.
Fiona Nunan 《Natural resources forum》2018,42(3):159-171
A plethora of terms are used to describe the form of governance of complex social‐ecological systems, such as multi‐level governance, polycentricity and network governance. This plethora of terms is associated with a diffuse literature from which it can be challenging to identify which variables are important for investigation of the governance system and what questions could be asked. The purpose of this article is to present the development of a guide for the analysis of the complex governance systems of renewable natural resources, informed by a breadth of literature from which key characteristics, challenges and concepts are identified. The guide consists of three dimensions: multiplicities of levels, actors and institutions; the existence, opportunities for, and challenges of, interactions within and between levels (vertical and horizontal interactions); and an assessment of governance performance through application of governance principles. The guide is applied to a case study of mangrove forests in Kenya, to illustrate its utility in generating understanding and identification of challenges and opportunities for more effective multi‐level governance. It is proposed that the guide could be beneficial to researchers and practitioners seeking to develop an understanding of structures, performance and outcomes of multi‐level governance. 相似文献
206.
The effects of temperature and precipitation on the formation of annual rings in stem wood of Siberian larch in ecotopes with optimal, insufficient, and excessive soil moistening are discussed. It is shown that precipitation fallen in the period from April to June, when the needles are formed, has a favorable effect on xylem increment. This relationship is better manifested in trees growing under conditions of insufficient soil moistening. In all types of ecotopes, a positive correlation between the annual ring width and warm and dry weather in July has been observed. 相似文献
207.
208.
Rashid M. Hassan 《Environment, Development and Sustainability》2003,5(3-4):403-418
Conventional measures of economic output, national income and wealth highly underestimate the value and contribution of natural resources to economic welfare. This paper makes estimates of the asset values and flow benefits of non-traded goods and services from forests and woodland resources in South Africa. Four benefit categories were included, namely direct consumptive use values (timber and non-timber products), non-consumptive use values (recreation for example), indirect use values (environmental services such as carbon sequestration, watershed protection, etc.), and non-use values (based on contingent valuation by tourists). Asset values were calculated knowing the change in physical stocks and the relevant prices. In South Africa, the increase in assets was equivalent to 1.1% of gross domestic product (GDP) (forests were improving, but fynbos deteriorating), and the flow benefits were equivalent to 0.8% of GDP. These are large magnitudes. 相似文献
209.
Vikram S. Negi Ravi Pathak K. Chandra Sekar R.S. Rawal I.D. Bhatt S.K. Nandi 《Journal of Environmental Planning and Management》2018,61(10):1722-1743
Ethnobotanical knowledge plays a significant role in plant diversity conservation and the curing of various ailments in remote rural areas of the Indian Himalayan Region (IHR). A total of 53 plant species from 27 families have been documented from the Byans valley and are used traditionally for the treatment of various diseases. Valley inhabitants have maintained a symbiotic relationship between natural resources and their cultural belief system by developing sacred forests/groves which conserve the region's plant diversity pool. Information on sacred natural sites and traditional beliefs was documented in order to understand the environmental and conservationist implications of these rules and practices. The study provides comprehensive information about eroding traditional knowledge and biodiversity conservation practices. This study could be a pilot to strengthen the conservation practices and sustainable utilization of frequently used bioresources by understanding the traditional knowledge system and conservation ethics of tribal communities in the Himalayan region. 相似文献
210.
A Water Yield‐Oriented Practical Approach for Multifunctional Forest Management and its Application in Dryland Regions of China
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Yanhui Wang Wei Xiong Stephan Gampe Neil Andrew Coles Pengtao Yu Lihong Xu Haijun Zuo Yunni Wang 《Journal of the American Water Resources Association》2015,51(3):689-703
Mountainous forest areas are vitally important for water supply in dryland regions which suffer from high erosion risk and severe water shortage. Massive afforestation, mainly for erosion control, may reduce the water yield and threaten local water supply security. Moreover, many over‐dense forests due to a strict logging ban policy have produced remarkably negative impacts for both forests (e.g., low timber quality, restricted natural regeneration, and high stand instability) and water yield. To satisfy the rapidly increasing demands on water supply and other services, a practical approach for managing forest stands in a multifunctional way, which particularly addresses water yielding, is urgently required. For this purpose, we integrated the existing knowledge and experience, designed an “ideal” stand structure to represent multifunctional forest (MFF) and determined its key parameters (a ground coverage of >0.7, a canopy density around 0.7, and an H/DBH ratio (tree height [m] to the diameter at breast height [cm]) of <0.7). Moreover, a decision process for MFF stand management was recommended as: (1) investigating the site quality; (2) identifying the site‐specific main forest functions; (3) quantifying the stand structure; (4) diagnosing the stand structure by comparing with the “ideal” one; and (5) arranging the functions/structure‐oriented management measures. In this way, the water‐yielding function can be improved and meanwhile other forest functions can be promoted. 相似文献