Holdridge Life Zone Research Articles

Simulating the Effect of Climate Change on Vegetation Zone Distribution on the Loess Plateau, Northwest China

A risk assessment of vegetation zone responses to climate change was conducted using the classical Holdridge life zone model on the Loess Plateau of Northwest China. The results show that there are currently ten vegetation zones occurring on the Loess Plateau (1950–2000), including alvar desert, alpine wet tundra, alpine rain tundra, boreal moist forest, boreal wet forest, cool temperate desert, cool temperate desert scrub, cool temperate steppe, cool temperate moist forest, warm temperate desert scrub, warm temperate thorn steppe, and warm temperate dry forest. Seventy years later (2070S), the alvar desert, the alpine wet tundra and the cool temperate desert will disappear, while warm temperate desert scrub and warm temperate thorn steppe will emerge. The area proportion of warm temperate dry forest will expand from 12.2% to 22.8%–37.2%, while that of cool temperate moist forest will decrease from 18.5% to 6.9%–9.5%. The area proportion of cool temperate steppe will decrease from 51.8% to 34.5%–51.6%. Our results suggest that future climate change will be conducive to the growth and expansion of forest zones on the Loess Plateau, which can provide valuable reference information for regional vegetation restoration planning and adaptive strategies in this region.

Listado taxonómico y distribución de los tricópteros inmaduros del departamento del Tolima

This taxonomic list of the Trichoptera larvae references data from the Zoological Voucher Collection at Universidad del Tolima, Colombia (Colección Zoológica de la Universidad del Tolima – CZUT-Ma). This collection includes 14 families and 35 genera of Trichoptera (out of the 15 families and 45 genera currently registered in Colombia).The most abundant families were Hydropsychidae, Hydroptilidae and Leptoceridae. The most abundant genera were Smicridea, Leptonema and Hydroptila. Regarding altitudinal distribution of the taxa found in the collection, Neotrichia, Leucotrichia and Smicridea exhibited the widest distribution, since they were found from 244m to 3533m. Results from a correspondence analysis performed on the taxa vs Holdridge life zones data, revealed that the highest species richness of the order Trichoptera in Tolima (Colombia) concentrated in the tropical dry forest, wet pre-mountain forest and lower wet mountain forest zones. © 2015. Acad. Colomb. Cienc. Ex. Fis. Nat. All rights reserved.

Geospatial Approach for Ecosystem Change Study of Lombok Island under the Influence of Climate Change

Lombok Island is categorized as a small island with an area o f 4738.7 km2 which makes it susceptible to climate change. Climate change is thought to have reduced the ability of forest biophysical and can cause damage to the ecosystem or a shifting of forest ecosystems. The purpose of this study is to identify the ecosystem changes in Lombok Island based on historical climate data and also to identify the vegetation domination based on ground truth result. Research study area covers the entire area of Lombok Island, West Nusa Tenggara. Data analysis was performed using Geographic Information Systems (GIS) to analyze the spatial distribution of ecosystem zones. Spatial data processing was performed by interpolation method to estimate values at unknown locations or adjacent points. Ecosystem types in this study were determined by Holdridge Life Zones which are generated from historical climate data from 1975 to 2012 and described by the time series map of 1975, 1995, and 2012. The result indicates that ecosystem change occurred in Lombok Island which has shown in time series map of ecosystem zone. There were only five life zones in 2012 which were tropical moist forest, tropical dry forest, tropical very dry forest, subtropical wet forest and subtropical moist forest. The tropical dry forest was seen to dominate the area of Lombok Island in 2012. The ground truth result shown that the vegetation domination matches each ecosystem zone in the recent time.

Controls on fallen leaf chemistry and forest floor element masses in native and novel forests across a tropical island

Litter chemistry varies across landscapes according to factors rarely examined simultaneously. We analyzed 11 elements in forest floor (fallen) leaves and additional litter components from 143 forest inventory plots systematically located across Puerto Rico, a tropical island recovering from large‐scale forest clearing. We assessed whether three existing, independently‐derived, landscape classifications (Holdridge life zone, remotely sensed forest type (leaf longevity combined with geology generalized to karst vs. non‐karst), and plot‐based measures of forest assemblage) would separate observed gradients. With principal component and regression analyses, we also tested whether climate‐, landscape‐ (geology, elevation, aspect, percent slope, slope position, distance from coast), and stand‐scale (tree species composition, basal area, density, stand age) variables explained variation in fallen leaf chemistry and stoichiometry. For fallen leaves, C, Ca, Mg, Na, and Mn concentrations differed by Holdridge life zone and C, P, Ca, Mn, Al, and Fe concentrations differed by forest type, where leaf longevity distinguished C and Ca concentrations and geology distinguished C, P, Ca, Mn, Al, and Fe concentrations. Fallen leaf C, P, Ca, and Mn concentrations also differed, and N concentrations only differed, by forest assemblage. Across several scales, fallen leaf N concentration was positively related to the basal area of putatively N2‐fixing tree legumes, which were concentrated in lower topographic positions, providing for the first time a biological explanation for the high N concentrations of fallen leaves in these locations. Phosphorus concentrations in fallen leaves by forest assemblages also correlated with the basal area of N2‐fixing legumes, and P and N concentrations decreased with mean age of assemblage. Fallen leaves from younger (<50 yr, 86% of the plots) and often novel forests had higher P, Fe, and Al and lower C concentrations and lower C/P and N/P ratios than fallen leaves from older forests, the latter due to a decrease in P rather than changes in N. These findings suggest that both N and P availability may currently be greater on the island than pre‐deforestation, and substantiate the unique roles that state factors play in contributing to the spatial heterogeneity of fallen leaf chemistry.

中国西南地区土地覆盖情景的时空模拟

PDF HTML阅读 XML下载 导出引用 引用提醒 中国西南地区土地覆盖情景的时空模拟 DOI: 10.5846/stxb201311042660 作者: 作者单位: 中国科学院地理科学与资源研究所,中国科学院地理科学与资源研究所,中国科学院地理科学与资源研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41271406）；国家重点基础研究发展计划（973计划）（2010CB950904）；资源与环境信息系统国家重点实验室青年人才培养基金项目 Spatio-temporal simulation of land cover scenarios in southwestern of China Author: Affiliation: State Key Laboratory of Resources and Environment Information System,Institute of Geographic Sciences and Natural Resources Research,CAS,State Key Laboratory of Resources and Environment Information System,Institute of Geographic Sciences and Natural Resources Research,CAS,State Key Laboratory of Resources and Environment Information System,Institute of Geographic Sciences and Natural Resources Research,CAS Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:气候植被类型的空间分布与土地覆盖类型的空间分布在时空层次上具有很好的相关性和一致性。在运用HLZ生态系统模型获得CMIP5的3种气候情景RCP26、RCP45、RCP85情景下西南地区未来90a（2011-2100年）HLZ生态系统时空分布情景数据的基础上，结合2010年土地覆盖现状数据，构建了土地覆盖情景的空间分析模型，并在此基础上，实现了西南地区未来90a土地覆盖情景的时空模拟分析。模拟结果表明：3种气候情景下，西南地区未来90a的落叶针叶林、落叶阔叶林、草地、耕地、冰雪、荒漠及裸岩石砾地等土地覆盖类型面积将呈逐渐减少趋势；常绿针叶林、常绿阔叶林、混交林、灌丛、湿地、建设用地、水体等土地覆盖类型面积则呈逐渐增加趋势。其中，湿地增加速度最快（平均每10a增加5.28%），荒漠及裸岩石砾地减少速度最快（平均每10a减少2.34%）。 Abstract:Numerous studies show that Karst area is more sensitive to influence of climate change and human activities, compared to the area in non-vulnerable condition. Therefore, quantitative simulating the land cover scenarios is important to understand the driving mechanism underlying land cover change in Karst area, and what policy should be carried out to prevent and reduce the land degradation. Especially, Karst area, as the typical ecological fragile zone, has been undertaking a series of ecological degradation, which have seriously affected the local socio-economic sustainable development. Karst area of Southwest China is one of the largest continuous Karst zone in the world, which major involves the Guizhou, Guangxi, Yunnan, Sichuan, and Chongqing province of China. This paper aims to develop a method for simulating the scenarios of land cover in Karst area and analyze its spatial distribution change under the global climate change. A simulation method of land cover scenario was developed on the basis of analyzing the correlation of spatial distribution between HLZ (Holdridge life zone) and the land cover, and the policy of basic farmland protection. According to the climate scenarios data of RCP26, RCP45, and RCP85 released by CMIP5 (the Fifth phase of the Coupled Model Intercomparison Project) and the land cover data in 2010 obtained from remoting sense images. Three land cover scenarios in Southwest China are respectively simulated in the next 90 years. The results show that three scenarios of land cover change have similar spatial landscape pattern and conversion trends. A gradual decrease was found in the following types of land cover, deciduous coniferous forest, deciduous broadleaf forest, grassland, cropland, ice and snow, and desert and bare rock; The other types of land cover would experience a moderate increase, namely, evergreen coniferous forest, evergreen broadleaf forests, mixed forest, scrublands, wetlands, construction land, water bodies and so on. Among the land cover types mentioned above, wetlands were projected to increase with the fastest rate (an increase of 5.28% per decade on average) and construction land were projected to increase most slowly (an average increase of 0.16% per decade), while desert and bare rock were forecasted to decline with the fastest rate (a decrease of 2.34% per decade on average) and cropland were forecasted to decrease most slowly (an average decrease of 0.26% per decade). It is worth noting that differences between land cover scenarios of 3 different climate scenarios lay in two aspects. On one hand, land cover scenario of every land cover type under RCP85 scenario stayed in top position in terms of the decadal change rate, especially, ice and snow decreasing far more than the other two scenarios. The next one was RCP45 scenario, land cover scenario of every land cover type under RCP26 scenario rank the last in terms of per decade change rate. On the other hand, each land cover type keep the same change trend under RCP85 and RCP45 scenarios during the following 90 years, while land cover scenario simulated with RCP26 data turn out to change in the opposite trend after 2070. Furthermore, the simulated result identify the method of land cover scenarios can avoid the difficulties which come from the complexity and uncertainty of mechanism analysis in land cover modeling, and suitable to simulate the land cover change on a regional scale. 参考文献 相似文献 引证文献

The climate of Carpathian Region in the 20th century based on the original and modified Holdridge life zone system

AbstractThe Holdridge life zone system has already been used a number of times for analysing the effects of climate change on vegetation. But a criticism against the method was formulated that it cannot interpret the ecotones (e.g. forest steppe). Thus, in this paper transitional life zones were also determined in the model. Then, both the original and modified life zone systems were applied for the climatic fields of database CRU TS 1.2. Life zone maps were defined in the Carpathian Region (43.5–50.5° N, 15.5–28° E) for each of five 20-year periods between 1901 and 2000. We estimated correctness of the result maps with another vegetation map using Cohen’s Kappa statistic. Finally, temporal changes in horizontal and vertical distribution of life zones were investigated. The coverage of boreal region decreased with 59.46% during the last century, while the warm temperate region became almost two and a half larger (257.36%). The mean centres of those life zones, which were not related to mountains, shifted northward during the investigation period. In case of the most abundant life zone types, the average distribution elevation increased. Using the modified model, the potential distribution of forest steppe could be also identified.

Mitigating climate change through afforestation: New cost estimates for the United States

We provide new cost estimates for carbon sequestration through afforestation in the U.S. We extend existing studies of carbon sequestration costs in several important ways, while ensuring the transparency of our approach. Our costs estimates have five distinguishing features: (1) we estimate costs for each county in the contiguous U.S., (2) we include afforestation of rangeland, in addition to cropland and pasture, (3) our opportunity cost estimates account for capitalized returns to future development (including associated option values) in addition to returns to agricultural production, (4) we develop a new set of forest establishment costs for each county, and (5) we incorporate data on Holdridge life zones to limit afforestation in locations where temperature and moisture availability prohibit forest growth. We find that at a carbon price of $50/ton, approximately 200 million tons of carbon would be sequestered annually through afforestation. At a price of $100/ton, an additional 100 million tons of carbon would be sequestered each year. Our estimates closely match those in earlier econometric studies for relatively low carbon prices, but diverge at higher carbon prices. Our results indicate a smaller, but still important, role for forest-based carbon sequestration in offsetting U.S. greenhouse gas emissions.

Geographic Differentiation of ColombianNeoleucinodes elegantalis(Lepidoptera: Crambidae) Haplotypes: Evidence for Solanaceae Host Plant Association and Holdridge Life Zones for Genetic Differentiation

AbstractThe purpose of this study was to examine the population structure of Neoleucinodes elegantalis (Guenée) (Lepidoptera: Crambidae) in relation to host plant association and ecological Holdridge zones. Adult collections were made in cultivated and wild Solanaceae species in 13 departments of Colombia. Sequencing of 658 bp of the mitochondrial gene Cytochrome Oxidase 1 on 103 individuals produced 25 haplotypes. Haplotypes Hl, H2, H4, and H7 were the most frequent and were geographically separated by the Andean mountains. We obtained an FST = 0.57 (P < 0.0001), where most of the genetic differentiation (42.64%) was between individuals within each department. Pairwise FST analysis produced higher genetic values between geographically separated departments than between closely related sites. H2 and H7 apparently behave as generalist populations, as they were found in different habitats and different hosts. The most divergent populations of N. elegantalis were found in southern Colombia, at a location were Solanun quitoense might have originated. Host plant association and environmental factors such as Holdridge life zones are playing an important role in the differentiation of N.elegantalis. Population structuring in N.elegantalis indicates that integrated pest management strategies used to control this species should consider the genetic differentiation of the species at different locations in Colombia.

An assessment of climate change impacts on the tropical forests of Central America using the Holdridge Life Zone (HLZ) land classification system

Ecological models have predicted shifts in forest biomes, yet there have been very few studies that have looked at the implications on carbon stocks due to these shifts. Carbon is closely correlated to biomass and constitutes an important characteristic of the forest ecosystem. It has implications for conservation and land use practices, especially for climate change mitigation strategies currently under discussion, such as REDD+. This study couples the Holdridge Life Zone (HLZ) classification with the ECHAM5 model, to evaluate the impacts of climate change using the Special Report on Emissions Scenarios (SRES) A2, A1B and B1 for the Central American region. We utilize methodologies which combine biophysical variables with model output to assess the impacts on carbon stocks for two time periods, 2000 and 2100, . Results show that overall, the tropical category of the HLZ classification gains area as a result of one type of HLZ shifting to another forest type. In many cases the shifts result in some categories of HLZ being lost in their entirety. Elevation-associated life zones are particularly vulnerable to future climatic changes. A strong point of our approach is that differences between disaggregate regional and aggregate country levels can be compared. We suggest that a critical focus of conservation and management efforts should be concentrated on where vulnerable biomes are at most risk (biomes that shift and/or reduce fall under the vulnerable category).

Assessing biome boundary shifts under climate change scenarios in India

Climate change and its cascading impacts are being increasingly recognized as a major challenge across the globe. Climate is one of the most critical factors affecting biomes and their distribution. The present study assessed shifts in biome types of India using the conceptual framework of Holdridge life zone (HLZ) model, minimum distance classifier and climatic datasets to assess the distribution pattern of potential biomes under climate change scenarios in India. Modelling was conducted on the entire region of India using various combinations; (i) current climate scenario, and, (ii) increased temperature and precipitation scenario. The geographical analysis identifies nineteen (19) HLZs in the Indian sub-continent; seven (7) biomes and nineteen (19) sub-biomes. The overall accuracy and kappa coefficient of the biome map prepared for current climate scenario was 82.73% and 0.75, respectively. With the changes in increasing temperature and precipitation scenario, the modelling results predict significant decrease in the area cover for tropical deserts (plains), tropical desert scrubs (lower montane), tropical moist forests (lower montane) and tropical wet forests (lower montane). Along with these changes, there have been substantial increases in the area cover for tropical dry forests (plains) and tropical very dry forests (plains), especially in central and southern India. The results show shifts from very dry tundra (alvar) to dry tundra (alpine) and moist tundra (alpine) and in some places tropical moist forests (sub-alpine) as well. In central India, decrease in tropical moist forests (lower montane) has been observed, while an increase in the area cover of tropical rain forests (plains) in northeastern India has been observed. It is important to understand the impacts and vulnerabilities of projected climate change on forest ecosystems so that better management and conservation strategies can be adopted for biodiversity and forest dependent communities. The knowledge of impact mechanisms will identify adaptation strategies for some conditions which will help in decreasing the susceptibility to anticipated climate change in the forest sector.

Land use impacts on freshwater regulation, erosion regulation, and water purification: a spatial approach for a global scale level

Rarely considered in environmental assessment methods, potential land use impacts on a series of ecosystem services must be accounted for in widely used decision-making tools such as life cycle assessment (LCA). The main goal of this study is to provide an operational life cycle impact assessment characterization method that addresses land use impacts at a global scale by developing spatially differentiated characterization factors (CFs) and assessing the extent of their spatial variability using different regionalization levels. The proposed method follows the recommendations of previous work and falls within the framework and principles for land use impact assessment established by the United Nations Environment Programme/Society of Environmental Toxicology and Chemistry Life Cycle Initiative. Based on the spatial approach suggested by Saad et al. (Int J Life Cycle Assess 16: 198–211, 2011), the intended impact pathways that are modeled pertain to impacts on ecosystem services damage potential and focus on three major ecosystem services: (1) erosion regulation potential, (2) freshwater regulation potential, and (3) water purification potential. Spatially-differentiated CFs were calculated for each biogeographic region of all three regionalization scale (Holdridge life regions, Holdridge life zones, and terrestrial biomes) along with a nonspatial world average level. In addition, seven land use types were assessed considering both land occupation and land transformation interventions. A comprehensive analysis of the results indicates that, when compared to all resolution schemes, the world generic averaged CF can deviate for various ecosystem types. In the case of groundwater recharge potential impacts, this range varied up to factors of 7, 4.7, and 3 when using the Holdridge life zones, the Holdridge regions, and the terrestrial biomes regionalization levels, respectively. This validates the importance of introducing a regionalized assessment and highlights how a finer scale increases the level of detail and consequently the discriminating power across several biogeographic regions, which could not have been captured using a coarser scale. In practice, the implementation of such regionalized CFs suggests that an LCA practitioner must identify the ecosystem in which land occupation or transformation activities occur in addition to the traditional inventory data required—namely, the land use activity and the inventory flow. The variability of CFs across all three regionalization levels provides an indication of the uncertainty linked to nonspatial CFs. Among other assumptions and value choices made throughout the study, the use of ecological borders over political boundaries was deemed more relevant to the interpretation of environmental issues related to specific functional ecosystem behaviors.

Shocks and Bribri Agriculture Past and Present

Shocks and Bribri Agriculture Past and Present

Land-cover changes of biome transition zones in Loess Plateau of China

The Holdridge life zone (HLZ) model has been improved to help classify the biome transition zone (BTZ) in China's Loess Plateau. A positive and negative transformation index of land-cover (PNTIL) was developed to quantitatively evaluate the land-cover changes in every type of BTZ. Three bioclimatic datasets, with a spatial resolution of 1km×1km, were used to classify the BTZ type in Loess Plateau. These include the mean annual biotemperature (MAB), average total annual precipitation (TAP) and potential evapotranspiration ratio (PER). In 1985, 1995 and 2005 land cover data was used to analyze the changes within BTZs. The results show that there are 14 BTZ types, which account for 25.21% of the total land-cover area in Loess Plateau. From 1985 to 2005, cultivated land decreased 0.93% per decade; on average wetland and water areas, woodland and grassland increased 3.47%, 0.24% and 0.06% respectively per decade. During this period the total rate of whole BTZ land-cover transformation decreased from 28.53% to 21.91%. Overall the total positive and negative transformed areas of land cover in BTZs displayed a decreasing trend. Moreover, the results indicate that the transition zones may have exhibited a greater change and landscape diversity than the adjacent biomes in Loess Plateau from 1985 to 2005.

Changes in global potential vegetation distributions from 1911 to 2000 as simulated by the Comprehensive Sequential Classification System approach

Vegetation classification models play an important role in studying the response of the terrestrial ecosystem to global climate change. In this paper, we study changes in global Potential Natural Vegetation (PNV) distributions using the Comprehensive Sequential Classification System (CSCS) approach, a technique that combines geographic information systems. Results indicate that on a global scale there are good agreements among maps produced by the CSCS method and the globally well-accepted Holdridge Life Zone (HLZ) and BIOME4 PNV models. The potential vegetation simulated by the CSCS approach has 6 major latitudinal zones in the northern hemisphere and 2 in the southern hemisphere. In mountainous areas it has obvious altitudinal distribution characteristics due to topographic effects. The distribution extent for different PNV classes at various periods has different characteristics. It had a decreasing trend for the tundra and alpine steppe, desert, sub-tropical forest and tropical forest categories, and an increasing trend for the temperate forest and grassland vegetation categories. The simulation of global CSCS-based PNV classes helps to understand climate-vegetation relationships and reveals the dynamics of potential vegetation distributions induced by global changes. Compared with existing statistical and equilibrium models, the CSCS approach provides similar mapping results for global PNV and has the advantage of improved simulation of grassland classes.

Effect of climate change over the past half century on the distribution, extent and NPP of ecosystems of Inner Mongolia

The response of natural vegetation to climate change is of global concern. In this research, changes in the spatial pattern of major terrestrial ecosystems from 1956 to 2006 in Inner Mongolia of China were analyzed with the Holdridge Life Zone (HLZ) model in a GIS environment, and net primary production (NPP) of natural vegetation was evaluated with the Synthetic model, to determine the effect of climate change on the ecosystem. The results showed that climate warming and drying strongly influenced ecosystems. Decreased precipitation and the subsequent increase in temperature and potential evapotranspiration caused a severe water deficiency, and hence decreased ecosystem productivity. Climate change also influenced the spatial distribution of HLZs. In particular, new HLZs began to appear, such as Warm temperate desert scrub in 1981 and Warm temperate thorn steppe in 2001. The relative area of desert (Cool temperate desert scrub, Warm temperate thorn steppe, Warm temperate desert scrub, Cool temperate desert and Warm temperate desert) increased by 50.2% over the last half century, whereas the relative area of forest (Boreal moist forest and Cool moist forest) decreased by 36.5%. Furthermore, the area of Cool temperate steppe has continuously decreased at a rate of 5.7% per decade; if the current rate of decrease continues, this HLZ could disappear in 173 years. The HLZs had a large shift range with the mean center of the relative life zones of desert shifting northeast, resulting a decrease in the steppe and forest area and an increase in the desert area. In general, a strong effect of climate change on ecosystems was indicated. Therefore, the important role of climate change must be integrated into rehabilitation strategies of ecosystem degradation of Inner Mongolia.

Plant geography upon the basis of functional traits: an example from eastern North American trees

Plant geographers have sought for decades to describe and predict the geographic distribution of vegetation types on the basis of plant function and its relationship with the abiotic environment. Traditionally this has been accomplished using categorical representations such as plant functional types. Increasingly, plant functional ecologists have sought to refine categorical functional types via quantitative functional traits in order to understand the ecological implications of trade-offs in plant form and function. Fewer works have focused upon testing whether commonly measured functional traits enhance our understanding of plant biogeography broadly and the geographic distribution of vegetation types in particular. Here we combine a continental-scale forest inventory data set containing 18 111 plots with a plant functional trait data set to ask: (1) Is there a strong relationship between the abiotic environment and the distribution of functional trait values in forest inventory plots? And (2) can different Holdridge life zones be distinguished upon the basis of their functional trait distributions? The results show geographic patterns of functional trait distributions that are often strongly correlated with climate and also show that the Holdridge life zones in the study area can be differentiated using a combination of functional traits.

Conservación de la biodiversidad en Costa Rica: análisis de la correspondencia entre áreas identificadas clave por su biodiversidad (Araceae, Arecaceae, Bromeliaceae y Scarabaeinae) y zonas de vida prioritarias para la conservación

This paper undertook an analysis of the distribution of high species richness and areas of endemism based on plants (Araceae, Arecaceae, and Bromeliaceae) and dung beetles (Scarabaeinae) inhabiting the different Holdridge Life Zones of Costa Rica. Using a geographic information system (GIS) we analyzed biogeographic provinces, in terms of their representativity in sampling areas, life zones, and protected areas. Species richness and endemism maps served as a base for conducting a gap analysis and defining 6 different levels of high priority conservation areas. What percentages of these priority areas are under some type of protection or conservation scheme and which of these areas should be enlarged were also investigated. The degree of feasibility that these areas under protection have for enlargement is indicated. A list is included of all the aforementioned registered species for Costa Rica, as well as their presence in the different Holdridge Life Zones and their endemism status. Four areas with the highest species richness were identifi ed, and 3 new areas of endemism are proposed. The most important conservation priority areas are the tropical wet forests on the northeastern lowlands, the Osa Peninsula region, and the premontane wet forest along the Guanacaste, Tilaran and Central mountain ranges. This study clearly demonstrates the need to include and compare different groups of organisms in biodiversityendemism studies, in order to obtain more robust and finer-grained studies.

Modeling Caribbean tree heights and crown widths

Abstract. Regression models to predict total tree height and maximum crown radius as a function of diameter at breast height were developed for Caribbean trees using data collected by the U.S. Forest Service in the Commonwealth of Puerto Rico and Territory of the U.S. Virgin Islands. Nonlinear models predicting height fit the data well with an overall pseudo-R2 = 0.9220, as did models of height to diameter by Holdridge life zone and by the most frequently encountered species. The linear model predicting maximum crown radius for all trees combined fit the data poorly (R2 = 0.3478). Crown model fits showed only moderate improvements when the data were modeled by species, crown class, and inventory measurement protocol, highlighting the variability of Caribbean forest tree crowns within and between species. Height models presented here will be useful for applications such as growth and yield simulation, forest health monitoring, and wildlife habitat modeling, but the crown radius prediction models only shoul...

The Melting Himalayas: Cascading Effects of Climate Change on Water, Biodiversity, and Livelihoods

The Greater Himalayas hold the largest mass of ice outside polar regions and are the source of the 10 largest rivers in Asia. Rapid reduction in the volume of Himalayan glaciers due to climate change is occurring. The cascading effects of rising temperatures and loss of ice and snow in the region are affecting, for example, water availability (amounts, seasonality), biodiversity (endemic species, predator-prey relations), ecosystem boundary shifts (tree-line movements, high-elevation ecosystem changes), and global feedbacks (monsoonal shifts, loss of soil carbon). Climate change will also have environmental and social impacts that will likely increase uncertainty in water supplies and agricultural production for human populations across Asia. A common understanding of climate change needs to be developed through regional and local-scale research so that mitigation and adaptation strategies can be identified and implemented. The challenges brought about by climate change in the Greater Himalayas can only be addressed through increased regional collaboration in scientific research and policy making.

A new statistical dynamic analysis on vegetation patterns in land ecosystems

As complex self-adaptive systems, land ecosystems usually tend to produce intricate vegetation patterns under specific environmental constraints, which have ever puzzled us for decades. In this paper, a universal principle on pattern formation of land ecosystems is highlighted as: a land ecosystem always tries to find an optimal process to acquire maximized flux under a certain constraint or price. The underlying microscopic dynamic mechanism that induces complex vegetation patterns in land ecosystems is then revealed. Based on the Holdridge life zone system, evolutionary dynamic processes and structural classifications of several typical vegetation patterns are then simulated and discussed. Good agreements between theoretical analyses and numerical results are found. This paper demonstrates that the new theoretical analyses and simulation technique can be possibly applied to the whole land ecosystem, not only benefiting academic study on the formation and dynamics of vegetation patterns, but also providing implications for vegetation classification, vegetation protection and soil erosion control.