抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

The Theory of Island Biogeography

Statistics for Spatial Data.

Much has been written about theory and practice in the law, and the tension between practitioners and theorists. Judges do not cite theoretical articles often; they rarely "apply" theories to particular cases. These arguments are not revisited. Instead the Essay explores the working and interaction of theory and practice, practitioners and theorists. The Essay starts with a story about solving a legal issue using our intellectual tools - theory, practice, and their progenies: experience and "gut." Next the Essay elaborates on the nature of theory, practice, experience and "gut." The third part of the Essay discusses theories that are helpful to practitioners and those that are less helpful. The Essay concludes that practitioners theorize, and theorists practice. They use these intellectual tools differently because the goals and orientations of theorists and practitioners, and the constraints under which they act, differ. Theory, practice, experience and "gut" help us think, remember, decide and create. They complement each other like the two sides of the same coin: distinct but inseparable.

Of Theory and Practice

http://people.forestry.oregonstate.edu/richard-waring/sites/people.forestry.oregonstate.edu.richard-waring/files/publications/Landsberg%20%26%20Waring%201997%20For%20Ecol%20Mgmt.pdf

A generalised model of forest productivity using simplified concepts of radiation-use efficiency, carbon balance and partitioning

The boreal forest, one of the largest biomes on Earth, provides ecosystem services that benefit society at levels ranging from local to global. Currently, about two-thirds of the area covered by this biome is under some form of management, mostly for wood production. Services such as climate regulation are also provided by both the unmanaged and managed boreal forests. Although most of the boreal forests have retained the resilience to cope with current disturbances, projected environmental changes of unprecedented speed and amplitude pose a substantial threat to their health. Management options to reduce these threats are available and could be implemented, but economic incentives and a greater focus on the boreal biome in international fora are needed to support further adaptation and mitigation actions.

https://www.alachuacounty.us/Depts/epd/EPAC/AAAS%20Boreal%20forest%20health%20and%20global%20change%20-%20819.full.pdf

Boreal forest health and global change

In Fennoscandia, use of the natural forest as a reference for restoration and management of forest biodiversity has been widely accepted. However, limited understanding of the structure and dynamics of the natural forest has hampered the applications of the natural variability approach. This is especially the case in areas, where the natural forests have almost totally vanished. This review was motivated by the idea that despite these diffi culties the essential features of the natural forest can be reconstructed based on biological archives, historical documents, research done in adjacent natural areas, and modeling. First, a conceptual framework for analyzing the relationship between forest structure, dynamics and biodiversity is presented. Second, the current understanding of the structure and dynamics of natural forests at different spatiotemporal scales in boreal Fennoscandia is reviewed. Third, the implications of this knowledge, and gaps in knowledge, on research and on practical restoration and management methods aimed at forest biodiversity conservation are discussed. In conclusion, naturally dynamic forest landscapes are complex, multiscaled hierarchical systems. Current forest management methods create disturbance and successional dynamics that are strongly scale-limited when compared with the natural forest. To restore some of the essential characteristics of the natural forest’s multiscale heterogeneity, diversifi cation of silvicultural and harvesting treatments, as guided by natural disturbance dynamics, is needed to produce more variation in disturbance severity, quality, extent, and repeatability.

Natural variability of forests as a reference for restoring and managing biological diversity in boreal Fennoscandia

Recent research in northern Europe has revised many long-held conceptions of the complexity of forest ecosystems and their natural structure and dynamics. The unveiling of the picture of natural characteristics of forest ecosystem structure and dynamics reveals much more diversity than its traditional complement, highlighting the importance of non-stand-replacing disturbances and the associated heterogeneous and dynamic stand and landscape structures. This increasing detail is a reflection of a fundamental change in the ecological understanding of forests as complex ecosystems. In particular, the generalization that the boreal forest is regulated by fierce stand-replacing disturbances, leading to the dominance of even-aged stand successions, has been disproved. However, this misconception has, until now, been repeated and used to legitimize the dominant practice of clear-cutting as a nature-based way to manage the forest. The practical conclusion of this review paper is that the dominating forest management model in North European boreal forests, which is based on the clear-cut harvesting of timber and growing of even-aged stands, is in contradiction with the variable and complex characteristics of the disturbance-succession cycle observed in naturally dynamic forests with negligible human impact. As a consequence, the structural variation of the boreal forest under management has been grossly truncated compared with its natural range. Because of this, and due to the scarcity of protection areas in many regions of northern Europe, it is not likely that the conservation of native biodiversity and ecological sustainability will be attained, assuming that the model of forest management remains unchanged. Thus, there is a strong incentive for change in the prevailing forest management model toward one that is based on natural ecosystem dynamics and an understanding of forests as complex systems.

https://bioone.org/journals/ambio-a-journal-of-the-human-environment/volume-38/issue-6/08-A-490.1/Forest-Management-and-Biodiversity-Conservation-Based-on-Natural-Ecosystem-Dynamics/10.1579/08-A-490.1.pdf

Forest Management and Biodiversity Conservation Based on Natural Ecosystem Dynamics in Northern Europe: The Complexity Challenge

Since WWII, forest management in Fennoscandia has primarily been based on even-aged stand management, clear cut harvesting and thinning from below. As an alternative, uneven-aged management, based on selection cutting of individual trees or small groups of trees, has been proposed. In this review we discuss the theoretical aspects of ecology and economics of the two management approaches. We also review peer-reviewed studies from boreal Fennoscandia, which have aimed at comparing the outcomes of uneven-aged and the conventional even-aged forest management. According to a common view the main obstacle of practicing uneven-aged forestry is its low economic performance. However, the reviewed studies did not offer any straightforward support for this view and several studies have found uneven-aged management to be fully competitive with existing even-aged management. Studies on the ecological aspects indicated that selection cuttings maintain mature or late-successional forest characteristics and species assemblages better than even-aged management, at least at the stand scale and in the short term. We conclude that although the number of relevant studies has increased in recent years, the ecological and economic performance of alternative management methods still remains poorly examined, especially for those stands with multiple tree species and also at wider spatial and temporal scales. For future research we advocate a strategy that fully takes into consideration the interdisciplinary nature of forest management and is better connected to social goals and latest theoretical and methodological developments in ecology and economics.

Even-Aged and Uneven-Aged Forest Management in Boreal Fennoscandia: A Review

The appearance of the natural disturbance dynamics paradigm in forest ecology has contributed to a more diversified view of forest dynamics Disturbances in forests range from small to large-scale and from abiotic to biotic, and the mix varies considerably among regions It is currently acknowledged that boreal forest disturbance and succes sional features may vary substantially according to the characteristics of the dominant tree species, local site conditions, landscape and regional climate This has important consequences for how forests ought to be managed by protection, management and restoration to produce renewable resources, maintain biodiversity, and provide ecosys tem services Focussing on Europe's conifer-dominated forests we present different dis turbances, disturbance regimes and forest vegetation types found in boreal, hemiboreal and mountain forests For developing practical approaches to biodiversity conservation it is useful to separate three broadly defined types of forest dynamics 1) succession after severe stand-replacing disturbances, 2) cohort dynamics related to partial disturbances and 3) gap dynamics caused by the death of individual trees or small groups of trees We use this classification to discuss and define approaches for conservation planning and sustainable forest management Developing management methods for maintenance of viable populations and important ecosystem processes requires an understanding of how the quality, size, juxtaposition and functional connectivity of the different forest vegetation elements affect species and ecosystem processes at the landscape scale We emphasise the need for both conservation of networks of forest with different dynamics and studying large intact forest areas which are representative for different ecoregions

Timo Kuuluvainen

Papers

Boreal forest health and global change

Natural variability of forests as a reference for restoring and managing biological diversity in boreal Fennoscandia

Forest Management and Biodiversity Conservation Based on Natural Ecosystem Dynamics in Northern Europe: The Complexity Challenge

Even-Aged and Uneven-Aged Forest Management in Boreal Fennoscandia: A Review

Boreal forest disturbance regimes, successional dynamics and landscape structures - a European perspective