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1.
Maintaining forest landscape connectivity is one of the most effective ways to alleviate natural forest fragmentation and biodiversity loss problems. Recently, graph theory based metrics have been used as powerful tools in the assessment of landscape connectivity. However, the functional features of landscape units at different structure levels, based on which outcomes can be enriched and advice can be given for practical applications, have been overlooked. In this study, a series of graph-based connectivity indices was calculated to 1) evaluate the optimal threshold distance, 2) identify the key landscape units at the component and patch levels, and 3) classify the functional types of components and patches and analyze functional patterns at different structural levels. The relationship between patch size and patch functional performance in maintaining landscape connectivity was discussed. With a natural forest area in Minqing County of China as the study area, recommendations regarding forest conservation and connectivity enhancement were provided based on the research conclusions. This study provides a way to comprehensively analyze habitat fragmentation and functional patterns for local forest conservation. 相似文献
2.
为了深入研究黔桂岩溶山区森林转型的空间分异特征及其影响因素,为山区森林恢复措施调整、生态环境保护及政策制定提供参考。本文从空间形态和功能形态两方面测度了森林转型特征,并采用SPSS和地理探测器等技术手段,从自然环境因子、社会经济环境因子2个方面分析了森林转型的驱动因素。研究结果如下:(1)1990–2015年,黔桂岩溶山区林地面积增加了673.5 km^2,总体上呈现U型曲线变化特征,即林地面积变化呈现“先减少再增加”的趋势,转折时点为2000年,黔桂岩溶山区正处于森林转型的后一个阶段——林地面积净增加的阶段。年均降水量、年均温度、到最近河流的距离、到最近农村居民点的距离、地形起伏度和坡度等6个影响因素对森林空间形态转型的贡献率最大。(2)研究时段内,研究区植被覆盖度等级变化趋势差异较大,其中极高覆盖度增幅最为明显,面积为154173.71 km^2。其他植被覆盖度等级在25年间均呈减少趋势,植被生态总体处于恢复过程中,其等级变化在空间分布上整体表现为北高南低的特征。森林功能形态转型受自然和社会经济因素相互作用的影响,年均温度、夜间灯光亮度、海拔和年均降水量是森林功能转型最重要的控制因素。从森林在空间形态和功能形态上的转变趋势来看,未来生态建设应从促进森林面积空间扩张为主向提升森林质量的内涵建设为主转型。 相似文献
3.
甘肃省摩天岭北坡木本植物叶性状变异及关联 总被引：1，自引：0，他引：1
调查了摩天岭北坡以常绿阔叶林带与落叶阔叶混交林为主的低海拔区(700~1 500m)和针阔叶混交林与亚高山针叶林为主的高海拔区(2 100~3 400m)的21个木本植物群落组成,测定了104种植物的比叶面积(SLA)、叶干物质含量(LDMC)、叶片全磷含量(TPC)、叶片全氮含量(TNC)、叶片全碳含量(TCC)以及叶片厚度(LT)等6个植物功能性状。采用相关性分析对6个植物功能性状的变异和关联进行分析。结果表明:(1)SLA、LT和TCC在高海拔区明显高于低海拔区,而LDMC和TNC表现出高海拔区低于低海拔区;(2)SLA均随海拔的升高表现出降低的趋势,而LDMC和LT都随海拔的升高呈现增加的趋势。低海拔区TCC和高海拔区TCC都随海拔的升高呈增加的趋势;低海拔区TNC和TPC随海拔的变化与高海拔区相反,TNC和TPC在低海拔区随着海拔的升高表现出增加的趋势,而在高海拔区随海拔的增加呈现降低的趋势。(3)在高、低海拔区,SLA与LDMC、LT和TCC均呈极显著的负相关关系(P<0.01),LDMC与LT和TCC呈极显著的正相关关系(P<0.01)。摩天岭北坡不同海拔区木本植物叶片功能性状与海拔的关系,反映了该区域木本植物的不同叶片功能性状对海拔决定的环境异质性的协同响应和适应。 相似文献
4.
赣南生态屏障区林地时空变化分情景模拟 总被引：1，自引：0，他引：1
基于2000年和2010年土地利用遥感数据,从自然、区位、交通、人口和经济4个角度选取驱动因子,利用Logistic-CA-Markov土地利用综合模型预测赣南森林有林地、灌木林、疏林地和其它林地4种林地类型在当前模式、规划模式和保护模式3种情景下的空间演变格局。结果表明：① 到2020年,在当前模式和规划模式,林地总面积将减少,在保护模式则出现增加,3种情景都体现出有林地和其它林地增加、疏林地和灌木林缩减的趋势,只是增减幅度不同,但不论何种情形林地的组成结构都将发生较大程度的变化;② 3种情景都是以疏林地→有林地、有林地→其它林地和灌木林→有林地这3种类型的转化为主,向有林地的转化分布都比较分散,而向其它林地的转化却集中在安远、信丰、于都、赣县四县交界处;③ 相较于当前模式,在规划模式下集中在安远县及其周边的有林地向其它林地的转化出现大量缩减,在保护模式下这种缩减更加明显。 相似文献
5.
Spatial heterogeneity is an inherent characteristic of natural forest landscapes, therefore estimation of structural variability, including the collection and analyzing of field measurements, is a grow... 相似文献
6.
森林生态系统具有重要的碳汇作用。目前,碳汇价格可以通过碳交易、碳税和固碳项目实际成本3种机制实现。本研究从森林植被碳汇功能发挥的过程出发,认为森林植被碳汇价值包括碳固定价值和碳蓄积价值两部分。在此基础上以樟子松(Pinus sylvestris var.mongolica)为例,采用固碳项目实际成本,模拟了森林植被在100年的生命历程中碳汇价值的动态变化过程。研究表明,单株樟子松碳固定的物理量和价值量动态过程曲线都呈倒"U"型;碳蓄积的物理量和价值量动态过程曲线都近似呈"S"型。在碳固定和碳蓄积价值叠加下,碳汇价值流量过程曲线近似呈"S"型,且逐渐趋近碳蓄积价值流量曲线。100年内,樟子松的碳汇总价值(资产价值)随着林龄逐渐增大,其中碳蓄积价值所占的比重逐渐增加。樟子松林分碳汇价值曲线与单株树木的曲线不完全相同,但是基本形态一致。 相似文献
7.
贡嘎山东坡亚高山林区土壤结构综合评价 总被引：5，自引：0，他引：5
土壤结构状况对森林水文生态功能的发挥具有重要作用,以青藏高原东部、长江上游亚高山天然林区不同林型下土壤为研究对象,通过20个土壤结构指标的分析、计算,运用主成分-聚类分析方法综合评价了该区土壤结构。结果表明:20个土壤结构性评价常用指标所反映的信息有较大的重叠性,4个主成分表达了全部信息的90%以上,表现出土壤团聚体及稳定性、固相物质空间排列形成的孔隙、细粒物质等在土壤结构性能中具重要意义;林木生长的成熟化、混交或乔灌结合对土壤结构性能有较强促进作用。研究结果对于土壤结构综合评价方法选择、加强森林经营与培育以促进土壤结构发育、充分发挥森林水文生态效应具有一定的指导作用。 相似文献
8.
以阿尔泰山森林生态系统为研究对象并依据《森林生态系统服务功能评估规范》（LY/T 1721—2008）,通过利用空间分析的方法对阿尔泰山森林资源二类调查数据处理分析,得到了阿尔 泰山不同类型森林生态系统的生态服务价值和阿尔泰山生态服务价值的影响因素。结果表明：阿 尔泰山森林生态服务价值量为 47 957.79×106 元·a-1,价值量的大小为：涵养水源＞固碳释氧＞保护 生物多样性＞净化大气环境＞保育土壤＞积累营养物质,其中涵养水源是主导服务功能;不同林 龄的生态服务价值量呈现为：成熟林＞过熟林＞近熟林＞中龄林＞幼龄林;按照林场划分,各个林 场的生态服务价值呈现富蕴林场＞阿勒泰林场＞新疆阿尔泰山两河源自然保护区＞布尔津林场
＞青河林场＞哈巴河林场＞福海林场的顺序。 相似文献
9.
2005-2013年中国新增造林植被生物量碳库固碳潜力分析 总被引：2，自引：2，他引：0
本文利用2005-2013年林业统计年鉴中每个省市新造林面积和遥感分类提取得到的2010年土地覆被类型,结合公开发表的各类森林生长方程和各个时期的森林存活率,估算了中国新造林在2005-2100年生物量碳库变化及其固碳潜力。结果表明：2005-2013年中国新造林面积达到4394×104 hm2,在自然生长状况下,到2020年新造林蓄积量增加16.8亿m3,生物量增加1.6 Pg,生物量碳库0.76 Pg C;新造林生物量碳库在2005-2100年中将增加2.11 Pg C,相当于目前现有森林生物量碳库的25%,约是过去20年森林总碳汇的1.5倍;新造林生物量碳密度逐年增加,最高达到48.1 Mg/hm2。整合林业统计年鉴以及遥感解译的森林类型对新造林生物量固碳潜力分析,研究表明新造林具有较大的碳汇潜力,对中国现有森林碳汇平衡有重要贡献。 相似文献
10.
新疆森林资源动态分析——基于RS与GIS的森林资源动态研究 总被引：13，自引：0，他引：13
利用RS与GIS技术对新疆境内的森林资源进行调查分析,以新疆全区为控制总体,采取卫星数据解译结合现地调查及抽样方法获取全疆森林资源数据。在GIS支持下,对1996、2001年两期卫星遥感调查数据进行对比。研究了新疆各类森林资源的动态变化。近五年森林资源变化的总趋势是林业用地、有林地、疏林地、苗圃、宜林地面积均有增加,森林覆盖率提高,活立木总蓄积量增加,实现了森林资源面积和蓄积双增长。全疆有林地面积由17331 km2增加到17837 km2,年均增加101 km2。森林覆盖率由原来的1.05 %上升到现在的1.08 %,提高了0.03 %。全疆活立木总蓄积由262416000 m3增加到289985200 m3,共增加27569200 m3,年均增加5514000 m3,年均净增率为2.00 %。分析结果表明;新疆森林资源总体呈上升趋势。但仍存在着天然林稀少、森林覆盖率低、林分年龄结构失调、树种单一等问题。 相似文献
11.
Shin Nagai Taro Nakai Taku M. Saitoh Robert C. Busey Hideki Kobayashi Rikie Suzuki Hiroyuki Muraoka Yongwon Kim 《Polar Science》2013,7(2):125-135
Evaluation of the carbon, water, and energy balances in evergreen coniferous forests requires accurate in situ and satellite data regarding their spatio-temporal dynamics. Daily digital camera images can be used to determine the relationships among phenology, gross primary productivity (GPP), and meteorological parameters, and to ground-truth satellite observations. In this study, we examine the relationship between seasonal variations in camera-based canopy surface indices and eddy-covariance-based GPP derived from field studies in an Alaskan open canopy black spruce forest and in a Japanese closed canopy cedar forest. The ratio of the green digital number to the total digital number, hue, and GPP showed a bell-shaped seasonal profile at both sites. Canopy surface images for the black spruce forest and cedar forest mainly detected seasonal changes in vegetation on the floor of the forest and in the tree canopy, respectively. In contrast, the seasonal cycles of the ratios of the red and blue digital numbers to the total digital numbers differed between the two sites, possibly due to differences in forest structure and leaf color. These results suggest that forest structural characteristics, such as canopy openness and seasonal forest-floor changes, should be considered during continuous observations of phenology in evergreen coniferous forests. 相似文献
12.
There are few throughfall data from southern hemisphere closed-forest, and none from Tasmanian callidendrous cool-temperate rainforest, which has a simpler structure than most primary rainforests. We determined throughfall, measured its local spatial variation, and tested its relationships with rainfall, rainfall intensity, wind speed, canopy dryness, canopy cover, and other structural variables in a cool-temperate callidendrous rainforest in Tasmania. Eighty-two percent of the precipitation was measured as throughfall, which occurred after 2.3 mm of rain fell on dry canopies. The cumulative rainfall in 25 randomly located funnel rain gauges on the forest floor varied from 160 to 567 mm. Canopy cover and other structural variables did not predict the spatial pattern of throughfall. While throughfall in rainfall events was related to rainfall amount and intensity, wind speed did not affect throughfall as a percentage of rainfall. Percentages of throughfall to rainfall over 100 for many low rainfall events may indicate a contribution of fog drip to precipitation on the forest floor. The high local spatial variability in throughfall indicates the mean moisture conditions on the forest floor may not be a good indicator of the potential for localised fire damage. 相似文献
13.
Nevenka Bogataj 《社会与自然资源》2014,27(8):867-881
Forest commons in Slovenia are a poorly known indigenous institution for common resource management. They are a functional entity linked to a specific community that establishes interpersonal and intergenerational ties, as well as a link to the resource. We refer to shared ownership of resource, once made of pastures; today forests prevail. Collective property management remained despite community changes and legislation development. Today registered forest commons represent approximately one-third of those that existed before 1945. We highlight seven developmental turns to explain their revival. Six indicators are used in the analysis of current conditions. Forest commons are a potentially effective response to forest management challenges in Slovenia but also a potential model of social cohesion, rational resource use, and a balance between forest use and conservation. However, they are plagued by state ignorance, which hinders statistically sound analyses. 相似文献
14.
Sanjay K. Srivastava Sameer Saran Rolf A. de By V. K. Dadhwal 《International journal of geographical information science》2014,28(3):427-454
Innumerable forest fire spread models exist for taking a decision, but far less focus is on the real causative factors which initiate/ignite fire in an area. It has been observed that the majority of the forest fires in India are initiated due to anthropogenic factors. In this study, we develop a geo-information system approach for management of forest fire in Mudumalai Wildlife Sanctuary, Tamil Nadu, India, with the objective to develop a forest fire likelihood model, integrating GIS and knowledge-based approach for predicting fire-sensitive initiation areas considering major causative and anti-causative factors. Amongst the various causative factors investigated, it was found that wildlife-dependent factor (antler collection and poaching) contributed significantly to fire occurrence followed by management-dependent factors (uncontrolled tourism and grazing), with much less influence of demographic factors. Similarly, anti-causative factor (stationing of anti-poaching/ fire camps) was considered as quite significant.
The likelihood model so developed, envisaging various factors and flammability, accounted for different scenarios as a result of pair-wise comparison on an ordinal scale in a knowledge matrix. The inferential statistics computed indicated the robustness of the model and its insensitivity to moderate changes. It makes it possible for this forest fire likelihood model to predict and prevent a forest fire in an effective and scientific manner because it can assume forest fire likelihood in real time and present in proper time. 相似文献
15.
《自然地理学》2013,34(4):345-359
Historical surveys have proven important for assessing changes in forest composition and for providing insights into the influences of human activities on forest ecosystems. We used GIS to compare past land-use/land-cover information from General Land Office (GLO) surveys taken in 1849/1851 with current forest composition to illustrate the extensive changes that have occurred in bottomland hardwood forest composition over the past 150 years in East Baton Rouge Parish (EBRP), Louisiana. Agricultural lands, hardwood wetlands, and urban lands increased in area at the expense of rangelands and swamplands. A comparison of forest composition between A.D. 1849/1851 and today illustrates that the bottomlands were once a cypress-tupelo gum association but are now an elm-ash-sugarberry association. These changes are related to expanding urban conditions and encroaching human activities (e.g., levee construction) that substantially changed surface hydrological properties, especially the potential for flooding. Bottomland hardwood forests provide important services to low-lying urban areas mainly through storage of flood waters. Without conservation efforts, bottomland hardwood forests will experience continued human-mediated changes. 相似文献
16.
尽管森林地被物在保水与养分循环中扮演重要角色,但我们仍然对由植被转换引起的森林地被物的变化缺乏了解。为评价不同人工林替代乡土灌丛对森林地被物水文特性的影响,我们选择了4种人工林（连香树Cercidiphyllum japonicum[Cj],油松Pinus tabulaeformis[Pt],华山松Pinus armandi[Pa],落叶松Larix kaempferi[Lk]）,以次生乡土灌丛（QC）（Quercus liaotungensis和Corylus heterophylla var.sutchuenensis为优势种）为对照。人工林种植于1987年,初始密度为2500株ha-1。我们发现针叶人工林地被物厚度和贮量明显大于次生灌丛地和阔叶人工林地。地被物最大持水量在各林地之间差异与厚度和贮量显示相同的趋势,我们认为其主要贡献因子为林地凋落物数量及单位重量凋落物的最大持水量差异。地被物吸水过程和吸水速率与浸泡时间分别呈对数与指数回归关系。吸水过程在各植被之间与地被物各层次之间明显不同,主要受各植被的凋落物叶结构与分解程度影响。我们的结果显示针叶林地被物储量明显高于阔叶林,这说明以针叶树种为优势的林地大量养分滞留在凋落物中,难于返还土壤被植物利用,同时,半分解层（F）和分解层（H）最大持水能力高于未分解层（L）,因此,改善林地微环境,促进L层地被物向F和H层转化,是改善人工林地被物水文功能的主要方法之一。 相似文献
17.
Hollie Grant 《社会与自然资源》2019,32(7):768-789
Why do environmental defenders continue to participate in community-based efforts to protect the environment despite threats to their lives and minimal success in deterring or punishing offenders? Examining Community Forestry initiatives in Cambodia, we find that forest protection is not only a means to gain environmental, economic, or social benefits, but also a means for forest defenders to assert themselves as political actors in relation to the state and other citizens. Rather than simply repressing and disciplining forest dwelling populations, violence against defenders shapes their subjectivity and re-politicizes their lives. Distinguishing between various forms of violence associated with different illicit forest users, we highlight how forest protection becomes a means of political self-expression and rights-based resistance as forest defenders reinterpret direct violence through experiences and understandings of structural and symbolic violence. Participation in CF thus unlocks ways of being political and contesting oppressive structures while acting within sanctioned institutions. 相似文献
18.
《Urban geography》2013,34(1):65-86
Relationships between attributes of the urban forest and the built environment and social characteristics of New Orleans, Louisiana are examined using several exploratory statistical techniques. In the relatively young field of urban forestry, much research has focused on the biophysical attributes and functional benefits of urban forests, including wildlife habitats, climatic amelioration, and noise abatement. Recognizing that urban forests are anthropogenic, the research reported here explores the urban forest in relation to urban land uses and social groups. Socioeconomic factors, as measured by census variables, are shown to be important determinants of the distribution of the urban forest as measured by tree canopy cover. 相似文献
19.
Development of efficient forest wildfire policies requires an understanding of the underlying reasons behind forest fire occurrences. Globally, there is a close relationship between forest wildfires and human activities; most wildfires are human events due to negligence (e.g., agricultural burning escapes) and deliberate actions (e.g., vandalism, pyromania, revenge, land use change attempts). We model the risk of wildfire as a function of the spatial pattern of urban development and the abandonment/intensity of agricultural and forestry activities, while controlling for biophysical and climatic factors. We use a count data approach to model deliberately set fires in Galicia, N.W. Spain, where wildfire is a significant threat to forest ecosystems, with nearly 100,000 wildfires recorded during a thirteen-year period (1999–2011). The spatial units of analysis are more than 3600 parishes. Data for the human influences are derived from fine-resolution maps of wildland–urban interface (WUI), housing spatial arrangements, road density, forest ownership, and vegetation type. We found wildfire risk to be higher where there are human populations and development/urbanisation pressure, as well as in unattended forest areas due to both rural exodus and a fragmented forest ownership structure that complicates the profitability of forestry practices. To better help direct management efforts, parameter estimates from our model were used to predict wildfire counts under alternative scenarios that account for variation across space on future land-use conditions. Policies that incentivize cooperative forest management and that constrain urban development in wildlands at hotspot fire locations are shown to reduce wildfire risk. Our results highlight the need for spatially targeted fire management strategies. 相似文献
20.
A case study is made of the Mendeleev volcano (Kunashir Island, Southern Kuril Chain) to carry out a quantitative assessment of the influence of magmatic energy of an active volcano on the thermal regime of the soil and the ground-level air level as well as on the water balance and forest formation processes in the insular volcanic landscape. It is established that the influent channels of steam-hydrotherms cause an anomalous rise in soil temperature thereby having a substantial influence on the structure and functioning of forest ecosystems. Using a specially developed method, we calculated the geotherm-caused temperature anomalies in the soil. Calculations showed that the forest communities of the Mendeleev volcanic landscape evolved into existence and persist under the same heat and energy conditions as their zonal marginalmainland counterparts. The active volcano compensates for a deficiency in the climatic resource and ensures a stable functioning and a structural configuration of these “climatically unjustified” (extrazonal) island-arc ecosystems. We have empirically substantiated the proposition that geothermal energy of passive volcanoes serves as the factor for acceleration evolution of the insular phytobiota. This constitutes the phenomenon of biogeocenological organization of the volcanogenic landscape in the continent-to-ocean transition zone. It is shown that the magmatic geotherms of the Mendeleev volcano promoted the transgression of species and whole communities from southern areas to this boreal-forest region. We examine the rearrangement of the forest cover toward an increase in its floro- and phytocenotic diversity, the formation of relatively stable boreal-subboreal forest ecosystem with subtropical relicts as well as rudimentary buffer forest communities. It is demonstrated that a geothermal heating of the soil on the slopes and at the foot of the volcanoes of the Kuril Ridge is a large-scale (rather than an exceptional) phenomenon in the hydrothermal regime of forest ecosystems of island-arc ecoregions. 相似文献