The influence of topography and fire in controlling landscape composition and structure in Sierra de Gredos (Central Spain)

Mediterranean landscapes are dynamic systems that undergo temporal changes in composition and structure in response to disturbances, such as fire. Neither landscape patterns nor driving factors that affect them are evenly distributed in space. Accordingly, disturbances and biophysical factors interact in space through time. The aim of this paper is to assess the relative influence of topography and fire on the landscape patterns of a large forested area located in Sierra de Gredos (Central Spain) through time. A series of Landsat MSS images from 1975 to 1990, and a digital elevation model (DEM) were used to map fires, assess topographical complexity and evaluate changes in landscape composition and structure. Functional regions across the entire landscape were identified using different classification criteria (i.e., percentage burned area and topographic properties) to model topographic and fire impacts at regional scales. A canonical variance partition method, with a time series split-plot design, quantified the relative influence and co-variation of topography and fire on land cover patterns through time. Main results indicated that analyzing portions of the landscape under similar environmental conditions and fire histories, the effects of different fire regimes on the spatio-temporal dynamics of main land covers can be highlighted. However, the impact of fire on landscape patterns was high variable among regions due to the different regeneration abilities of main land covers, the topographic constraints and the fire histories of each region. Hence, broad patterns of fire related variance and co-variation with topography emerged across the entire area due to the different conditions of each landscape portion in which this large Mediterranean landscape was divided. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Human settlement ecology and chimpanzee habitat selection in Mali

Customary land-use practices create distinctive cultural landscapes, including landscapes where abandoned settlements host vegetation that attracts wild animals. Understanding how landscape patterns relate to land-use history can help clarify the ecological effects of particular land uses. This study examines relationships between chimpanzee habitat selection and Maninka settlement practice, to determine how settlement history has affected chimpanzee habitat in Mali’s Bafing Biosphere Reserve, where conservation practitioners assume that the characteristic settlement pattern reflects a process of settlement expansion into undisturbed habitat. Three types of data are reported: (1) ethnographic interviews on settlement history and practice; (2) systematic sampling of chimpanzee habitat use; and (3) ground-based mapping of settlement sites, surface water, and fruit-tree patches. These data show that the Maninka have a shifting settlement system, meaning that most sites are occupied for only relatively brief periods; and that some abandoned settlement sites host fruit-tree patches that are seasonally important chimpanzee habitat. Two main conclusions are: (1) settlement expansion has not occurred; instead, historic settlement has created habitat that is both attractive and available to chimpanzees. Anthropogenic habitat does not appear to be vital for chimpanzee survival, but it spatially and temporally supplements natural habitats. (2) Conservation policies meant to reduce the presumed threat of settlement expansion may have initiated an unintended, long-term threat of habitat loss for chimpanzees. While settlement practices may be a component of short-term threats to chimpanzees, such as hunting, when addressing these threats conservation practitioners should consider long-term settlement processes to avoid creating new threats.     

Relationships of dead wood patterns with biophysical characteristics and ownership according to scale in Coastal Oregon,USA

Dead wood patterns and dynamics vary with biophysical factors, disturbance history, ownership, and management practices; the relative importance of these factors is poorly understood, especially at landscape to regional scales. This study examined current dead wood amounts in the Coastal Province of Oregon, USA, at multiple spatial scales. Objectives were to: (1) describe current regional amounts of several characteristics of dead wood; (2) compare dead wood amounts across ownerships; (3) determine the relative importance, according to spatial scale, of biophysical and ownership characteristics, to regional dead wood abundance. Dead wood plot data were evaluated with respect to explanatory variables at four spatial scales of resolution: plots, subwatersheds, watersheds and subbasins. The relationships of dead wood characteristics with biophysical attributes and ownership were diverse and scale-specific. Region-wide dead wood abundance and types varied among ownerships, with public lands typically having higher amounts of dead wood and more large dead wood than private lands. Regression analysis of total dead wood volume indicated that ownership was important at the subbasin scale. Growing season moisture stress was important at plot, subwatershed, and watershed scales. Topography was important at the two coarser scales. Multivariate analysis of dead wood gradients showed that ownership was important at all scales, topography at the subbasin scale, historical vegetation at watershed and subbasin scales, and current vegetation at plot and subwatershed scales. Management for dead wood and related biodiversity at watershed to landscape scales should consider the distinct dynamics of snags and logs, the importance of historical effects, and the relevance of ownership patterns.     

Modeling tsunami damage in Aceh: a reply

In reply to the critique of Baird and Kerr, we emphasize that our model is a generalized vulnerability model, built from easily acquired data from anywhere in the world, to identify areas with probable susceptibility to large tsunamis—and discuss their other criticisms in detail. We also show that a rejection of the role of trees in helping protect vulnerable areas is not justified in light of existing evidence.     

Landscape context and selection for forest edge by breeding Brown-headed Cowbirds

We evaluated support for four alternate hypotheses explaining the distribution of breeding Brown-headed Cowbirds (Molothrus ater) in forests at varying distances from the forest edge in three Midwestern USA landscapes with varying amounts of forest fragmentation (core forest area ranged from 5 to 70%). We focused on breeding cowbirds’ use of forest because of the risk of nest parasitism to forest-dwelling hosts and to identify factors affecting breeding cowbird habitat selection. We compared distances of cowbird locations in the forest from the forest edge (“edge distances”) to distances of random forest locations in the entire landscape or within individual cowbird home ranges. We analyzed 1322 locations of 84 cowbirds across three landscapes. We found support for the landscape context hypothesis that breeding cowbird preference for forest edge varied with landscape context. Ninety percent of cowbird locations were within 150–350 m of forest edge, despite the overall availability of forest at greater distances from edge (as far as 500–1450 m) both within cowbird home ranges and the entire forested landscape. Cowbird preference for edge varied by landscape context largely due to differences in the availability of forest edge. In a highly fragmented forest cowbirds utilized the entire forest and likely viewed it as “all edge.” In less fragmented forests, cowbirds preferred edge. We consider how variation in cowbird edge preference might relate to patterns in host abundance, host diversity, and host quality because cowbird movements indicate they are capable of using forest farther from edges.     

信阳市南湾水库库区森林植被调查分析

信阳市南湾水库库区森林植被南湾水库库区的水资源涵养和水土保持具有重要的作用。本文对水库加区的森林植被的环境,资源状况,类型进行了调查分析,并提出了保护管理的建议。     

我国森林生态旅游发展刍议

论述了旅游及森林生态旅游的重要性,分析了我国森林生态旅游发展现状、教育现状及研究水平,并指出了我国目前森林生态旅游发展中存在的主要问题及今后的发展方向。     

福建省近10年主要森林病虫害发生趋势、特点及成因的探讨

概述了福建省近１０年主要森林病虫害发生发展趋势和特点,并分析探讨其原因     

试论森林生态系统是湖南生态环境建设的主体

作者依据我省生态环境和省情与水情等情况,论证了森林生态系统是我省生态环境建设的主体,提出了兴林以改善生态环境的观点,对当前和今后我省的林业工作具有指导意义。     

宜昌市经济林发展现状,问题及对策

目前宜昌市经济林的发展中存在较多问题,除品种结构不合理、经济效益低、管理粗放、科技含量低外,其突出问题是：加工滞后,生产、加工、销售脱节,没有形成产业链条。在今后的经济林发展中,应加强组织协调,理顺管理体制;加大科技含量,实行科学管理;广筹资金,增加投入;以市场为导向,建立经济林发展的产业运行机制,使经济林发展、加工、销售进入良性循环的轨道,实现优质、高产、高效。