勐腊县林地景观格局分析

利用2006年勐腊县森林资源二类调查数据,在ARCGIS 9和FRAGSTAT 3.3软件支持下,选取有代表性的林地景观格局指标:景观斑块密度、分维数、聚集度、破碎化、多样性指数、优势度、均匀度等来描述勐腊县林地景观格局.结果显示研究区优势度较低,异质性不高;景观中有一定的优势类型,以自然景观占优势.橡胶林景观破碎化程度较低,斑块较为完整.混交林景观连通性好,结构稳定.半自然景观、农地景观破碎化程度较高.     

勐腊县林地景观格局分析

利用2006年勐腊县森林资源二类调查数据，在ARCGIS9和FRAGSTAT3．3软件支持下，选取有代表性的林地景观格局指标：景观斑块密度、分维数、聚集度、破碎化、多样性指数、优势度、均匀度等来描述勐腊县林地景观格局。结果显示研究区优势度较低，异质性不高；景观中有一定的优势类型，以自然景观占优势。橡胶林景现破碎化程度较低，斑块较为完整。混交林景观连通性好，结构稳定。半自然景观、农地景观破碎化程度较高。     

The role of complex agroforestry systems in the conservation of forest tree diversity and structure in southeastern Ghana

The role of different agroforestry systems in the conservation of plant diversity and forest structure has not been directly compared in many agricultural dominated landscapes. In this study, we investigated tree diversity and forest structure in a complex agroforestry landscape traditionally grown for cocoa and mixed food crops and compared these to the natural forest in southeastern Ghana. The study was carried out using 36 25 m × 25 m plots. There was significant difference [95% Confidence Interval (95% CI)] in the native forest/non-crop tree species richness between the natural forest and the agroforest farmlands but species richness was similar between the cocoa and mixed food crops agroforests. The density of native forest/non-crop trees was significantly higher (P < 0.05) in the natural forest but similar between cocoa and mixed food crops agroforest. Similarly, the basal area of native forest/non-crop trees was significantly higher (P < 0.05) in the natural forest but comparable between cocoa and food crops agroforest. Of the 20 most abundant native forest/non-crop trees recorded, 12 of them showed significant responses (P < 0.05) to land use change with nine of the species significantly abundant in the natural forest relative to the agroforest systems. Eighteen native forest/non-crop trees species in the agroforestry systems were commonly recorded as being used; 100% of them being used as fuel wood with 83.3 and 77.8%, respectively, used as medicines and materials. The findings of this study suggests that although complex agroforestry systems are a poor substitute for the natural forest the heterogeneous mosaic landscape in which complex agroforestry forms part can be strategically managed to maximize the benefits of both sustainable agriculture production and conservation of plant diversity by acting as buffer between protected areas and intensively managed areas.     

Ecological integrity of remnant montane forests along an urban gradient in the Sierra Nevada

Urban development typically has extensive and intensive effects on native ecosystems, including vegetation communities and their associated biota. Increasingly, urban planning strives to retain elements of native ecosystems to meet multiple social and ecological objectives. The ecological integrity of native forests in an urbanizing landscape is challenged by a myriad of impacts, such as forest management and invasive species. Environmental protection efforts in the Lake Tahoe basin, spanning the California/Nevada border in the Sierra Nevada mountains, over the past half century have resulted in the retention of thousands of parcels of remnant native forest located throughout the urbanizing landscape. The basin landscape provides an opportunity to evaluate the effects of land development on the composition and structure of remnant native forests along a gradient of urbanization. We sampled 118 sites located in remnant forests in the lower montane zone surrounded by 0–70% development. We also sampled forest structure in the landscape surrounding 75 of these sites to evaluate the contribution of remnant forests to the retention of native forest elements in the larger landscape. We characterized plant species composition and cover, vertical structure, and the density of trees, snags, and logs, as well as levels of ground disturbance and human activity. We found that remnant native forests retained much of their compositional and structural character along the development gradient, including large tree density, total canopy cover, and plant species richness. Notable exceptions were reductions in the density and decay stage of snags and logs, and the density of understory trees. We also observed increases in the richness and cover of herb and grass species and increases in the number of exotic plant species. In contrast, structural complexity was reduced in the landscape surrounding forest remnants in all measures except large tree density. We conclude that remnant native forests contribute significantly to maintaining native species in an urbanizing landscape, and that land conservation practices have an important role to play in protecting native forest ecosystems.     

Tropical reptiles in pine forests: Assemblage responses to plantations and plantation management by burning

Worldwide, the land area devoted to timber plantations is expanding rapidly, especially in the tropics, where reptile diversity is high. The impacts of plantation forestry and its management on native species are poorly known, but are important, because plantation management goals often include protecting biodiversity. We examined the impact of pine (Pinus caribaea) plantations, and their management by fire, on the abundance and richness of reptiles, a significant proportion of the native biodiversity in tropical northern Australia, by (i) comparing abundance and diversity of reptiles among pine plantations (on land cleared specifically for plantation establishment), and two adjacent native forest types, eucalypt and Melaleuca woodlands, and (ii) comparing reptile abundance and richness in pine forest burnt one year prior to the study to remove understorey vegetation with pine forest burnt two years prior to the study. We also examined the influence of fire on reptile assemblages in native vegetation, by comparing eucalypt woodland burnt two years prior to the study and unburnt for eight years. To quantify mechanisms driving differences in reptile richness and abundance among forest types and management regimes, we measured forest structure, the temperatures used by reptiles (operative temperature) and solar radiation, at replicate sites in all forest types and management regimes. Compared to native forests, pine forests had taller trees, lower shrub cover in the understorey, more and deeper exotic litter (other than pine), and were cooler and shadier. Reptile assemblages in pine forests were as rich as those in native forests, but pine assemblages were composed mainly of species that typically use closed-canopy rainforest and prefer cooler, shadier habitats. Burning did not appear to influence the assemblage structure of reptiles in native forest, but burning under pine was associated with increased skink abundance and species richness. Burned pine was not warmer or sunnier than unburned pine, a common driver of reptile abundance, so the shift in lizard use after burning may have been driven by structural differences in understorey vegetation, especially amounts of non-native litter, which were reduced by burning. Thus, burning for management under pine increased the abundance and richness of lizard assemblages using pine. Pine plantations do not support the snake diversity common to sclerophyllous native forests, but pine may have the potential to complement rainforest lizard diversity if appropriately managed.     

金沟岭林场森林景观分类及景观变化研究

以吉林省汪清林业局金沟岭实验林场为例,介绍了一种基于森林资源二类调查数据的森林景观类型划分方法。划分景观要素类型的因子一级为土地覆盖类型,二级为优势树种组。在景观分类的基础上分析了1987-1997年10a问金沟岭实验林场森林景观空间格局变化。1987年和1997年主要的景观要素类型为针阔混交林、针叶混交林、落叶松林和阔叶混交林,1987年的斑块个数为592块,1997年为946块。斑块个数大幅度增加,反映出森林景观破碎化的趋势。10a问,景观多样性指数和相对丰富度指数降低,优势度指数有所增加。文章对营林活动对森林景观变化的影响进行了初步分析,发现景观类型变化较大的林班也是作业强度比较大的林班,景观斑块数量变化最大的林班也是作业强度比较大的林班。     

Dispersal potentials determine responses of woody plant species richness to environmental factors in fragmented Mediterranean landscapes

While maximizing plant species richness continues to be central in the design, conservation and reforestation action plans, plant life histories are receiving increasing attention in assessments for the conservation of biodiversity in fragmented landscapes. We investigated the determinants of woody plant species (trees, shrubs and climbers) richness in the forest patches of the Guadalquivir river valley, a Mediterranean agricultural landscape with ∼1% forest cover. We analyzed three species richness variables, total, and those corresponding to species with short-distance (ballistic, barochorous, myrmecochorous and short-distance anemochorous) and long-distance (anemochorous, endozochorous, exozoochorous, hydrochorous and dyszoochorous) dispersal systems, which significantly characterize earlier and late successional stages, respectively. We selected eleven predictor variables related to habitat structure (patch area, shape, distances to the nearest patch and reserve, and general isolation), physical environment (temperature, precipitation, elevation, and lithological heterogeneity), and anthropogenic influences (disturbance and proportion of old-growth forest). We used ordinary-least-squares multiple regression (OLS) and the Akaike's information criterion (corrected for spatial autocorrelation) and derived indices to generate parsimonious models including multiple predictors. These analyses indicated that plant species richness increase primarily along with increasing patch area and decreasing disturbance, but also detected secondary effects of other factors when dispersal was considered. While the number of species with potential long-distance dispersal tended to increase in more isolated patches of areas with greater precipitation and lithological heterogeneity (e.g. highlands at the valley edges), the number of species with short-distance dispersal increased towards drier and less lithologically complex zones with shorter between-patch distances (e.g. central lowlands). Beyond emphasizing the need to consider dispersal in fragmentation studies, our results show that woody plant species richness would be favoured by actions that increase patch area and reduce anthropogenic disturbances particularly in lowland forests.     

Live fences as tools for biodiversity conservation: a study case with birds and plants

Live fences may act as tools for biodiversity conservation by providing habitat for native species and increasing connectivity in the landscape. We studied the influence of live fence characteristics on species richness and fence use by birds by examining both local and landscape factors. We studied three types of live fences: planted fences of a native tree, planted fences of an exotic, and spontaneous. They were either connected to forest fragments or isolated, and were all within a pasture matrix. Spontaneous and planted live fences maintain a diverse plant (77 shrub and tree species) and bird communities (98 species). Fence types strongly differed in vegetation composition and structure. We found that by analyzing each fence characteristic independently, there was no difference in bird richness or abundance. However, there was a significant correlation when plant richness, structure, and connectivity were analyzed together. This could be the result of some variables counterbalancing each other. Birds used fences for a variety of purposes including foraging, breeding, and moving across the landscape. Native birds and plants used live fences as habitat and refuge in a landscape where large forest tracts have been lost for decades. Live fences in conjunction with small forest fragments maintain a diverse array of plant and birds species that are a subsample of the species originally found in the landscape before extensive deforestation. We recommend the establishment of live fences, allowing growth of spontaneous understory.     

The effects of forest patch size and ownership structure on tree stand characteristics in a highly deforested landscape of central Poland

Forest structure is influenced by the origin, history and manner of forest management. All these aspects may affect the occurrence of many forest dwelling organisms. We investigated the simultaneous impact of forest patch size and ownership structure on selected forest characteristics in central Poland. We sampled stand composition, the DBH of particular tree species, basal area, species number and species diversity in all 32 forest patches found in a farmland-dominated area of 150 km². Forest ownership status was linked to patch size: large patches were state-owned and small ones were private. Ownership status also affected the average DBH and basal area of all tree species pooled, with lower DBH and basal area found in private forests. The share of deciduous trees was negatively affected by forest size, while pine was positively affected, which could suggest that forest management and economic interests may be related to this factor. The share of non-native species was higher in state forests. Our results showed that forest patch size could be associated with its ownership status, which is commonly ignored in research on the relationship between forest size and species occurrence. Historical as well as sociological aspects related to private forests in Poland are also presented.     

浙西北天然次生林群落物种多样性研究

对浙西北地区天然次生林群落植物物种多样性特征进行了研究,测定了群落植物生长型构成以及各层次植物物种的重要值,采用多种测度方法计算了群落各层次植物物种的丰富度指数、均匀度指数和多样性指数。结果表明：（1）浙西北地区天然次生林群落各层次优势种比较明显,乔木树种以青冈为主,灌木树种以柃木和檐木占优势,草本植物则以箬竹为主;（2）该地区天然次生林群落植物物种比较丰富,乔木树种种数最多,草本植物稀少;就各层次而言,草本层物种数最多,乔木层和灌木层比较接近,各层次的均匀度指数的趋势是灌木层最高,草本层最低,乔木层居中;以多种指标计算各层次物种多样性指数结果均显示,灌木层多样性指数最高,草本层最低,尽管草本层具有最高的丰富度;（3）封育时间长、人为干扰轻的地区具有较高的物种多样性指标以及数量指标,有利于生物多样性的保护。     

Spatial pattern analysis for quantification of landscape structure of Tadoba-Andhari Tiger Reserve,Central India

Landscape structure is often regarded as an important factor that governs the distribution and abundance of species.Therefore it is critical to understand the landscapes and their dynamics.Patterns of landscape elements strongly influence the ecological characteristics.This study was designed to document and map the current status of the tropical dry deciduous forest of the Tadoba-Andhari Tiger Reserve(TATR),Central India,(using IRS P6 LISS IV data)and to describe its landscape structure at three levels of organization viz.landscape,class,and patch.The study area was classified into 10 land cover classes that include 6vegetation classes.The landscape structure was analyzed using FRAGSTATS using 12 set of indices.The TATR landscapes have a total of2,307 patches with a mean patch size of 25.67 ha and patch density of 1.7patches per km2.Amongst all land cover classes,mixed bamboo forest is dominant—it occupied maximum area(77.99%)—while riparian forest is least represented(0.32%).Mixed forest has maximum number of patches among all vegetation classes.Results have shown that despite being dominant in the area,mixed bamboo forest has low patch density(0.25/100 ha).Dominance of mixed bamboo forest is attributed to large patch sizes and not to the number of patches.This study has focussed on the approach of integrating satellite forest classification and forest inventory data for studying forest landscape patterns.     

杭州钱江新城 CBD 公园植物景观研究

通过现场踏勘和典型样地法,对杭州新地标钱江新城CBD公园植物景观进行调查,并对其植物多样性和植物群落结构作了相关分析。结果表明,钱江新城CBD公园现有种子植物60科85属108种（含种以下等级）,植物种类比较丰富,其中乔灌草、常绿与落叶乔木、常绿与落叶灌木种类比例较为合理,植物景观表现多样;植物群落结构以复层混交型为主,主要包括落叶阔叶林、常绿阔叶林、常绿落叶阔叶混交林3类,季相景观和生态性较为明显;积极可进入型、消极可进入型、不可进入型3个类型植物空间,分别占22.2％、16.7％、61.1％,绿地空间类型多,但对城市公园来说,可进入型空间比不可进入型空间更重要,应适当增加可进入型植物空间来满足钱江新城CBD公园人口相对集聚性特点。     

Breeding bird community composition in different successional vegetation in the montane coniferous forests zone of Taiwan

To examine the relationship between forest succession following fire and the composition of bird communities, we investigated the vegetation structure, bird population density, foraging behavior and guild structure in bamboo grasslands (11 years since the last fire), pine savanna (41 years), pine woodland (58 years), old-growth hemlock forest (never burned), and old-growth spruce forest (never burned) in the Tatachia area of central Taiwan. Canopy height, total foliage cover, tree density, total basal area of tree, total basal area of snags, foliage height diversity, and tree species richness all increased with successional age. However, shrub cover peaked in intermediate successional stages. The vertical profile of foliage cover was more diverse in later successional forests, which had more breeding bird species and ecological guilds. All the breeding bird species recorded in early and intermediate stages were also found distributed in the late successional forests. Because Taiwan has high precipitation and humidity, and most forest fires in Taiwan are caused by human activities, forest fires and large areas of early successional vegetation were probably rare in the mountain areas of Taiwan prior to the arrival of humans. Therefore, bird species have not had enough time to adapt to areas with early or intermediate successional vegetation. Moreover, late successional forests host all the major plant species found in the early and intermediate stages and have higher foliage height diversity index, which was positively correlated with the bird species richness and bird species diversity index in this study. As a result, all breeding bird species and guilds in the area can be found in late successional forests. Efforts for conserving avian diversity in Taiwan should focus on protecting the remaining native old-growth forests.     

南方低山丘陵区村域森林景观及植物群落特征

目的 探索南方低山丘陵区农村地区科学的森林恢复方式,改善森林结构及维护生物多样性,以保障森林生态系统的可持续发展和森林资源的永续利用。 方法 基于高分辨率GF-2数据和实地调查,以浙江省杭州市临安区昔口村为研究对象,对其森林景观及植物群落特征进行调查研究。 结果 昔口村森林面积占村域总面积的80.80%,主要林分类型有阔叶林、针阔混交林、马尾松林、杉木林、竹林、香榧林,村域内天然林、人工混交林面积小,以人工单层纯林为主,林下植被盖度偏低,植物多样性明显丧失。大部分乔木树高、胸径偏低。 结论 昔口村森林生态系统整体结构简单、多样性较低,若持续传统的造林、经营方式,势必会导致林分退化、地力衰退等问题。建议对现存的阔叶林、针阔混交林进行封育、改造,促进其向优质的常绿阔叶林转化,对马尾松生态公益林进行改造,引种补植乡土树种营造混交林,用材林、经济林采用小面积种植的方式,选择当地乡土阔叶树种、适生阔叶树种营造混交林作为绿色隔离带与小面积用材林、经济林镶嵌种植,并辅以科学的抚育经营措施。     

模拟常熟地区自然群落的植物景观设计

近年来,随着乡土景观营造运动的兴起,模拟自然植物群落的植物景观设计也逐渐引起人们的重视(Clark et al.,1998;Kielbaso,2008).通过研究分析某地区自然群落的基本类型、层次结构,从而有目的借鉴该地区自然群落的景观,在提高园林植物配置的科学性及艺术性、体现当地植物景观特色等方面具有重要的意义(苏雪痕,1983).     

Diversity and composition of tropical secondary forests recovering from large-scale clearing: results from the 1990 inventory in Puerto Rico

The extensive recovery from agricultural clearing of Puerto Rican forests over the past half-century provides a good opportunity to study tropical forest recovery on a landscape scale. Using ordination and regression techniques, we analyzed forest inventory data from across Puerto Rico’s moist and wet secondary forests to evaluate their species composition and whether the landscape structure of older forest affected tree species composition of recovering forests at this scale. Our results support conclusions from studies conducted in Puerto Rico at smaller scales and temperate forests at larger scales that timing of abandonment and land use history are of overwhelming importance in determining the species composition of recovering forests. Forest recovery is recent enough in Puerto Rico that previous land use is clearly evident in current species composition, and creates new forest communities. As demonstrated in other work, physical factors such as elevation and substrate co-vary with land use history, so that the species composition of the forest landscape results from the interplay between biophysical and socioeconomic forces over time. Our results also indicate that increasing the distance to the largest forest patches occurring in the landscape 12 years previous had a small negative impact on species richness but not species diversity or community composition. We conclude that land use history has as much influence in species composition as biophysical variables and that, at the scale of this study, there is no large influence of forest landscape structure on species diversity or composition.     

Conservation of forest biodiversity and ecosystem properties in a pastoral landscape of the Ecuadorian Andes

High Andean cloud forests are home to a diversity of unique wildlife and are important providers of ecosystem services to people in the Andean regions. The extent of these cloud forests has been widely reduced through conversion to pasture for livestock, which threatens the forests’ ability to support biodiversity and provide ecosystem services. This paper explores whether impacts on woody plant biodiversity and four ecosystem properties (woody plant species richness, juvenile timber tree abundance, soil organic matter content and soil moisture) from converting forest to pasture can be mitigated if some woody forest vegetation is maintained within pastures. Woody vegetation in pastures was found to conserve those woody plant species that are more tolerant to exposure and grazing, but conservation of the high montane cloud forest community required areas of forest from which livestock were restricted. The sampled sites clustered according to woody plant species cover; these clusters represented a gradient from pasture with patches of shrubs to mature forest. Clusters differed in both woody plant species richness and number of juvenile timber trees whereas soil organic matter and soil moisture were observed to be similar among all clusters. This suggests that the different habitats may have some equivalent ecosystem properties. We conclude that the presence of woody vegetation in pastures may reduce some of the impacts of converting forest to pasture, but should not be considered a substitute for protecting large areas of forest, which are essential for maintaining woody plant species diversity in high Andean cloud forest.     

Forest patches in Imperata grassland and prospects for their preservation under agricultural intensification in Northeast Luzon, The Philippines

Frequent burning and grazing and cultivation of cash crops increasingly threaten forest patches in hilly grassland in Northeast Luzon, yet their importance as a resource with multiple environmental functions and forest products persists. The aim of this study is to identify different types of forest patches, and their condition under present land-use intensification, and discuss prospects for their integration into sustainable local farming systems. Five types of forest patches are distinguished, both natural and planted ones, including rows of trees, woody patches, gallery forests, hill-slope forests and homegarden conglomerations. Natural woody patches and gallery forests in Imperata grassland are subject to degradation and land-use conversion under conditions of agricultural intensification. Woody patches in grassland affected by frequent burning and grazing cover small areas (66% below 50 m² as opposed to 28% in protected grassland) and contain relatively few woody plant species (25 woody species in total as opposed to 82 where protected). Yet where well managed, they may provide a variety of products for sale and subsistence, covering emergency needs and giving off-season cash income to rural communities. Moreover they serve like the gallery forest various ecological functions, carrying valuable indigenous tree species, retaining soil base nutrients, providing a continuous supply of organic matter and intercepting fine earth soil particles removed from bare surfaces. It is suggested that forest-patch management systems may be developed, taking into account both patch diversity and the diverse needs of rural communities, and to strengthen existing and undervalued functions of forest patches as permanent elements in an agricultural landscape.This revised version was published online in November 2005 with corrections to the Cover Date.     

Effects of landscape patterns on species density and abundance of trees in a tropical subdeciduous forest of the Yucatan Peninsula

Most studies of the effects of fragmentation and landscape patterns on plant communities focus on particular patches and on local species richness (α-diversity), while few studies examine different patch-types at the whole landscape level and address effects on abundance and composition of species or functional groups. The present study aims to identify and characterize relationships between patch-type metrics and species density and abundance of trees using four tropical subdeciduous forest landscapes in the Yucatan Peninsula considering the entire landscape as the unit of study. Species density and abundance of different groups of tree species resulting from hierarchical clustering were related to landscape patterns of patch-types (area, edge, shape, similarity and contrast) using regression analysis and Akaike Information Criterion (AIC). The abundance of tree species in the oldest stages of succession was associated with percentage of land of a patch-type. Total area may favor the establishment of shade-tolerant tree species in the study area because as the area of forest patches increases, the area of forest interior conditions also increases. Conversely, the abundance of species at early and intermediate stages was related to total edge contrast and edge density, respectively. Fragmentation increases the proportion of edge zones of a patch-type, creating contrasting microclimate conditions that could promote the establishment of pioneer and light-demanding species. Thus, the combined effect of total area and edge length of a patch-type may enhance total tree species richness in the study area by favoring species with different life-history strategies. The appearance of area, shape, edge and contrast in most of the regression models suggests that some generalization can be made about the effects of spatial geometry of patch-types on species composition and abundance of tropical trees. Understanding associations between landscape metrics and species density and abundance of objectively derived groups or guilds of species can provide important insights on the effects of fragmentation and landscape pattern on these guilds and on overall α-diversity, as well as guidelines for their conservation and management.     

上海半自然森林更新苗物种组成与多样性研究

城市半自然森林具有独特的群落结构和生物多样性特征,研究城市化影响的半自然森林更新特征,可以为城市生物多样性保育与地带性植被恢复重建提供借鉴。文章以上海辰山残存半自然森林1 hm^2固定监测样地为对象,调查分析半自然森林更新苗的物种组成特征。结果表明:1 hm^2样地更新苗共5 937株,分属22科32属37种,其中上海自然分布的乡土种占57.89%,明显高于城市人工林的乡土树种比例;香樟、构树、天竺桂、朴树和小蜡等5种更新苗占总数的57.2%,聚集性分布格局明显;在11个植被群落类型中,各类型更新苗的丰富度普遍较高,不同树种的更新苗存活和发育潜力存在差异。