Simulating the cumulative effects of multiple forest management strategies on landscape measures of forest sustainability

While the cumulative effects of the actions of multiple owners have long been recognized as critically relevant to efforts to maintain sustainable forests at the landscape scale, few studies have addressed these effects. We used the HARVEST timber harvest simulator to predict the cumulative effects of four owner groups (two paper companies, a state forest and non-industrial private owners) with different management objectives on landscape pattern in an upper Michigan landscape managed primarily for timber production. We quantified trends in landscape pattern metrics that were linked to Montreal Process indicators of forest sustainability, and used a simple wildlife habitat model to project habitat trends. Our results showed that most trends were considered favorable for forest sustainability, but that some were not. The proportion of all age classes and some forest types moved closer to presettlement conditions. The trend for the size of uneven-aged patches was essentially flat while the average size of patches of the oldest and youngest age classes increased and the size of patches of the remaining age classes decreased. Forest fragmentation generally declined, but edge density of age classes increased. Late seral forest habitat increased while early successional habitat declined. The owners use different management systems that cumulatively produce a diversity of habitats. Our approach provides a tool to evaluate such cumulative effects on other landscapes owned by multiple owners. The approach holds promise for helping landowner groups develop and evaluate cooperative strategies to improve landscape patterns for forest sustainability.     

超级居群:连接生境多样性和生物多样性之桥(英文)

在达尔文(1859)看来,新物种只有通过竞争或者自然选择的方式淘汰原有物种才能进入由其他物种占据的生境并成功定居下来。然而,新物种进入生境并成功定居还有另外一个途径,那就是由于超级居群能在全球尺度上改变整个地球环境,从而能在原有环境中创造出一些全新的微环境来,正是这些全新的微环境使新物种避开了和原有定居者的剧烈竞争,很容易地进入了一直由其他物种占据的生境中并成功地定居下来。换句话说,超级居群导致了全球环境的分化,导致了全球尺度上的生境多样性。同时,超级居群通过环境的异质化为新物种准备好了很多全新的微环境,新物种在全新的微环境中的成功定居实现了新物种和原有定居者的长期共存。而这种长期共存导致了整个生物圈的生物多样性的增加。超级居群是地球上很多新环境的创造者,是生境多样性和生物多样性之间的桥梁,据此就能很容易地解释新物种为什么不时能和原有定居者共存甚至依赖于原有定居者,从而导致二者间剧烈竞争缺失的现象。     

Historical influences dominate the composition of regenerating plant communities in abandoned citrus groves in north-central Florida

The question of what determines plant community composition is fundamental to the study of plant community ecology. We examined the relative roles of historical land use, landscape context, and the biophysical environment as determinants of plant community composition in regenerating citrus groves in north-central Florida. Results were interpreted in light of plant functional traits. Herbaceous and woody plants responded differently to broad-scale variables; herbs correlated most strongly with surrounding land cover at a scale of 8 km, while the only significant determinant of woody species distributions was local land use history. There were significant correlations between herbaceous species and spatial context, habitat isolation, environmental variables, and historical variables. Partial Mantel tests indicated that each variable provided a unique contribution in explaining some of the variation in the herbaceous dataset. The correlation between woody plants and local historical variables remained significant even with other effects corrected for. In the herbaceous community, species composition was linked to functional traits much as expected from classical theory. While spatial influences in our study system are important for both woody and herbaceous plants, the primary determinant of plant community composition in regenerating citrus groves is historical land use. Our results suggest that the fine-scale mechanisms of local competition, tolerance and facilitation invoked by many classical studies may ultimately be less important than land use history in understanding current plant community composition in regenerating agricultural areas.     

小兴安岭地区森林保护与生物多样性探析

论述了森林保护与生物多样性的关系,提出保护森林和生物多样性的措施。     

我国森林生物多样性变化的评价研究

应用控制论中“黑箱”理论的原理 ,参考经济合作与发展组织 (OECD)对环境政策影响的评价和芬兰森林资源核算的研究 ,创造性地使用压力 -状态响应评价法 ,设计了森林生物多样性变化评价的框架、指标和计算公式 ,并使用该方法对我国 1973年 - 1998年的森林生物多样性的变化进行了评价。评价结果表明 :1973年 -1998年 ,我国森林生物多样性的压力越来越大 ;森林生态系统多样性先逐渐上升 ,尔后又逐渐下降 ;森林物种多样性和森林生物多样性总体趋势增加 ,但第四次资源清查之后有所下降     

临安昌化常绿阔叶林群落生物多样性初步研究

通过样地法对临安昌化的常绿阔叶林群落进行调查,主要调查乔木层和灌木层的结构,计算分析各群落的乔木层、灌木层的重要值,乔木层的物种多样性指数。对草本层取小样方进行调查测量,了解草本层的植物构成并计算了草本层的盖度。分析临安昌化常绿阔叶林的群落结构后认为,该常绿阔叶林属顶级群落,具重点保护价值。     

The influence of regulatory forest policy tools on biodiversity measures for forests in Ukraine

The transition from a state-oriented forest economy to a market-oriented one requires a critical analysis of the set of tools designed to implement state forest policies. One of the important goals of Ukrainian forest policy is conservation of the biodiversity of forest ecosystems. This paper analyzes the influence of two of the regulatory forest policy instruments (zoning and prohibition of final harvesting) on the diversity of woody vegetation using Tobit regression. Data on the forest resources of the Sumy administrative province in Ukraine are used for the analysis. Additionally, we look at how diversity of woody vegetation is affected by the form of forest tenure.     

Kebon tatangkalan: a disappearing agroforest in the Upper Citarum Watershed,West Java,Indonesia

A comprehensive study was carried out on a typical indigenous agroforestry system, called kebon tatangkalan, in the changing agricultural landscape of the Upper Citarum Watershed, West Java, Indonesia. The main objectives of the study are to elucidate the structural patterns, multidimensional functions, and dynamics of this multi-layered agroforest. The study has identified 12 groups of different plant assemblages indicating that this type of agroforest contributes considerably to the heterogeneity of the agricultural landscape in the study area. Multivariate analysis suggests that elevation and slope are the biophysical factors that correlate most significantly with the distribution of plant species in kebon tatangkalan. The presence of this man-made vegetation is currently declining from the landscape due to population growth and rapid regional economic development. Serious effort to revitalize this traditional agroforest is needed to prevent its disappearance. Introduction of highly productive species and establishment of integrated policies in regional land-use planning and management are measures that should be taken into account in preserving this traditional agroforestry system.     

生物多样性的形成、维持机制及其宏观研究方法

关于生物多样性的形成与维持机制 ,虽有众多假说 ,但均未形成完善的理论体系。不同的学者从不同的角度出发 ,研究了诸多生态因子与生物多样性的关系 ,得出了许多结论、导出了不少争议。本文主要简述了生物因子 (如生产力、生物量、种间关系、土壤微生物 )和非生物因子 (干扰与空间异质性、气候、土壤因子等 )与生物多样性之间的相互作用机理、人类活动对生物多样性的影响 ,以及在生物多样性影响机制研究中所用的 3S技术与数学方法。总之 ,我们应坚持综合作用的观念 ,从不同的时间和空间尺度、在不同的对象层次上 ,全面、深入地研究各类生物和非生物因子与生物多样性之间的相互作用机理 ,才能得出关于生物多样性的形成与维持机制的全面、完善的理论