Increasing tree cover while losing diverse natural forests in tropical Hainan,China

To protect biodiversity and improve environmental conditions, China has invested billions of dollars in reforestation and payments for ecosystem service programs. Here, we examine the Sloping Land Conversion Program, the largest such program in the world and found that after 13 years of implementation at our study site, it has had negative impacts on natural tropical forests. GIS and remote sensing techniques revealed that both natural forests and natural shrub and grasslands were replaced by non-native monocultural plantations on Hainan Island, China, a key tropical biodiversity hotspot. Under current Chinese policy, these plantations are classified simply as “forests”, with the assumption that they are equivalent to natural forests. This lack of a distinction in forest quality has led to substantial deforestation and plantation expansion, including encroachment into protected areas on Hainan. Additional social and economic drivers of these changes were identified by examining the participants in this program and their actions. Without a new ecologically based definition of forests and new goals for reforestation, such programs designed to improve ecosystem services, and forest quality may actually threaten remaining natural forests and other vegetation types in Hainan and in other areas of mainland China.     

The influence of socioeconomic, environmental, and demographic factors on municipality-scale land-cover change in Mexico

Land-cover change is the result of complex multi-scale interactions between socioeconomic, demographic, and environmental factors. Demographic change, in particular, is thought to be a major driver of forest change. Most studies have evaluated these interactions at the regional or the national level, but few studies have evaluated these dynamics across multiple spatial scales within a country. In this study, we evaluated the effect of demographic, environmental, and socioeconomic variables on land-cover change between 2001 and 2010 for all Mexican municipalities (n?=?2,443) as well as by biome (n?=?4). We used a land-cover classification based on 250-m MODIS data to examine the change in cover classes (i.e., woody, mixed woody, and agriculture/herbaceous vegetation). We evaluated the trends of land-cover change and identified the major factors correlated with woody vegetation change in Mexico. At the national scale, the variation in woody vegetation was best explained by environmental variables, particularly precipitation; municipalities where woody cover increased tended to be in areas with low average annual precipitation (i.e., desert and dry forest biomes). Demographic variables did not contribute much to the model at the national scale. Elevation, temperature, and population density explained the change in woody cover when municipalities were grouped by biome (i.e., moist forest, dry forest, coniferous forest, and deserts). Land-cover change at the biome level showed two main trends: (1) the tropical moist biome lost woody vegetation to agriculture and herbaceous vegetation, and (2) the desert biome increased in woody vegetation within more open-canopy shrublands.     

Changes in the dry tropical forests in Central India with human use

Understanding changes in forest composition and structure is important to help formulate effective policies that promote future ability of forests to provide local livelihood needs, habitat and ecosystem services. This is particularly important in dry tropical forests that are ecologically different from other forests and are heavily used by local, forest-dependent residents. In this study, we identify biophysical, demographic and use factors associated with differences in species diversity, vegetation structure (abundance at different size classes), biomass and relative abundance of species across the Kanha–Pench landscape in Central India. We sampled vegetation in twenty transects across different human and livestock population densities and frequencies of use. We found that biomass, species diversity and vegetation (abundance at different size classes) are negatively associated with increasing population density, and species composition at different size classes is significantly different at higher frequencies of use at low population densities. Lack of difference in species composition at high population densities may be due to colonization and growth of individuals at some of these sites due to creation of new ecological niches and gaps at high human use. Relative abundance of species at different size classes also varies with frequency of use and population density. Results suggest that human use is altering relative abundance of species, which may change long-term forest composition and thus alter biomass and vegetation structure of the forest. We conclude that human use is an agent in altering long-term composition that can alter availability of tree species for local use and other ecosystem services.     

Impacts of climate change on Chinese ecosystems: key vulnerable regions and potential thresholds

China is a key vulnerable region of climate change in the world. Climate warming and general increase in precipitation with strong temporal and spatial variations have happened in China during the past century. Such changes in climate associated with the human disturbances have influenced natural ecosystems of China, leading to the advanced plant phenology in spring, lengthened growing season of vegetation, modified composition and geographical pattern of vegetation, especially in ecotone and tree-lines, and the increases in vegetation cover, vegetation activity and net primary productivity. Increases in temperature, changes in precipitation regime and CO₂ concentration enrichment will happen in the future in China according to climate model simulations. The projected climate scenarios (associated with land use changes again) will significantly influence Chinese ecosystems, resulting in a northward shift of all forests, disappearance of boreal forest from northeastern China, new tropical forests and woodlands move into the tropics, an eastward shift of grasslands (expansion) and deserts (shrinkage), a reduction in alpine vegetation and an increase in net primary productivity of most vegetation types. Ecosystems in northern and western parts of China are more vulnerable to climate changes than those in eastern China, while ecosystems in the east are more vulnerable to land use changes other than climate changes. Such assessment could be helpful to address the ultimate objective of the United Nations Framework Convention on Climate Change (UNFCCC Article 2).     

The recovery of the lower montane cloud forest in the Mucujún watershed, Mérida, Venezuela

High deforestation rates in tropical countries continue to reduce forest cover and thereby habitat quantity and quality. However, in some places the forest is recovering and expanding thus offsetting the biodiversity and ecosystem service losses. In order to characterize the forest recovery, land use and land cover (LUC) changes were analyzed using aerial photographs, taken between 1952 and 2009, of a peri-urban watershed in the Andes region of Venezuela. The qualities of the changes were assessed using landscape indices and hemeroby indicators. In that period, the forest cover increased about 18 %, mainly due to abandoned pastures on steep slopes. At the same time, the urban area expanded about 4 % on valley bottoms, while pastures and crop fields were reduced about 20 %. The results also showed that forest patches were aggregating, whereas pastures were fragmenting. A reduction in direct human impacts on forests growing on abandoned pastures resulted in a slight recovery of the lower montane cloud forest structure and plant composition. But non-native species were found in all LUC categories. During the study period, we documented not only forest recovery, but also urban area growth, intensified land use and invasions by non-native species all of which could partially counterbalance the positives of forest recovery.     

Scenarios and story lines: drivers of land use change in southern Mexico

The study presents three scenarios of land use and cover change (LUCC), the most important factor for environmental degradation in southern Mexico. We developed story lines and quantitative projections for regional scenarios based on historic LUCC processes, environmental policies, socioeconomic drivers, stakeholder consultations and official planning documents to gain a better understanding of drivers of LUCC, and quantitative scenarios were modeled with DINAMICA-EGO. Regionally specific interactions between social and natural systems are recognized, and detrimental policies and policy options for landscape conservation and management for sustainability are acknowledged in a base line, variant and alternative scenario. Incongruent policies and ineffective ground implementation of conservation actions were identified as the critical underlying drivers of deforestation and forest degradation that could lead to a severe reduction in natural forests, while the local socioeconomic situation stays precarious. The baseline scenario parts from an analysis of historic LUCC processes and shows the consequences of LUCC tendencies: 73% of temperate forests and 50% of tropical forests would get deforested until 2030. In the variant scenario, these tendencies are adjusted to planning goals extracted from official documents and recent changes in public policies. The alternative scenario further addresses policy options for fostering conservation and sustainable development, but because of the time lag of implementation, still 59% of temperate forests and 36% of tropical forest would get lost until 2030. Nevertheless, this represents a reduction of 13% of forest loss and 11% less pastureland due to the proposed measures of conservation, and sustainable management, including strategies for reforming agricultural systems, agricultural and forestry policies and trade, land tenure and livelihood risk management.     

The influence of forest/grassland proportion on the species composition,diversity and natural values of an eastern Austrian forest-steppe

Eastern Austrian forest-steppe remnants are extremey important both from conservation and a scientific perspective, yet case studies integrating the examination of the grassland and the forest components are relatively scarce. Consequently, the knowledge on how the pattern of forested vs. non-forested patches influences species composition and diversity remains rather limited. In this study, we compared three sites with different forest/grassland proportions: grassland with a low canopy cover, a mosaic area with alternating forest and grassland habitats, and a forest with some canopy gaps. Our aim was to find out which one of them is the best for conservation purposes. We found that the grassland and the mosaic area had a similar composition, while the forested one was distinct from them. The mosaic vegetation seemed to be the most species rich, also hosting a high number of red-listed species. Beside forest-related and grassland-related species, the mosaic plot also supported some edge-related plants. We conclude that the preservation of mosaic-like forest- grassland habitats is the most favorable for conservation aims. Nevertheless, several species, among them some red-listed ones, were clearly linked either to the forest or to the grassland plot. Therefore, even though mosaics deserve a special attention, open grasslands and xeric forests should also be preserved.     

Characteristics and drivers of forest cover change in the post-socialist era in Croatia: evidence from a mixed-methods approach

Extensive forests in Croatia represent an important biological and economic resource in Europe. They are characterised by heterogeneity in forest management practices dating back to the socialist planned economy of the pre-1991 era. In this study we investigated the difference in rates of deforestation and reforestation in private- and state-owned forests during the post-socialist period and the causal drivers of change. The selected region of Northern Croatia is characterised by a high percentage of privately owned forests with minimal national monitoring and control. We used a mixed-methods approach which combines remote sensing, statistical modelling and a household-based questionnaire survey to assess the rates of forest cover change and factors influencing those changes. The results show that predominantly privately owned forests in Northern Croatia have recorded a net forest loss of 1.8 % during the 1991–2011 period, while Croatia overall is characterised by a 10 % forest cover increase in predominantly state-owned forests. Main factors influencing forest cover changes in private forests are slope, altitude, education structure, population age and population density. The results also show that the deforestation in private forests is weakening overall, mostly due to the continuation of the de-agrarisation and de-ruralisation processes which began during socialism.     

The livelihood potential of non-wood forest products: The case of Mbooni Division in Makueni District, Kenya

Forestry is a productive sector with significant effects on meeting national socio-economic and environmental functions as well as the improvement of rural livelihoods. Non-wood forest products (NWFPs) in particular have been widely advocated by conservation and development organisations as potential alternative livelihood strategies, particularly among vulnerable forest dependant households. Like in most tropical countries, NWFPs are relevant in the sustainable development of Kenya that is particularly endowed with important forest resources. Kenya hosts about 17 million ha of forested land (about 3.51% of the total Sub-Saharan Africa forest cover by 2000), of which about 16,865,000 ha is under natural forest (EarthTrends: Forests, grasslands and drylands, 2003). Outside the gazetted forests, there are other large tracks of forests in trust lands, including national parks and reserves, hill forest reserves and privately owned lands covering about 0.5 million ha (Kenya’s forest resource assessment in the EC-FAO Partnership Programme Report, 2000; The Kenya Forests Act, 2005). Woodlands, bushlands and wooded grasslands, mainly found in the arid and semi-arid lands cover 37.6 million ha, while forest plantations (started in 1946) cover about 170,000 ha of land (The Kenya forestry master plan, 1994–2020, 1994). In most NWFPs endowed regions of the country however, this socio-economic and environmental potential is still unrealized. We illustrate the latter by a case study of NWFPs use and management in four villages in Mbooni Division of Makueni District, Kenya. The division was chosen because of its relatively high NWFPs availability, particularly from South Mbooni forest that is located at a distance less than 5 km for an estimated 80% of the interviewed households. Data used for the analysis was collected through a fieldwork survey carried out on women (35+ years) in August, 2005. One hundred and sixty (160) NWFPs are harvested (from plant and animal species) and used mainly for food, income generation (supplemental) and medicinal purposes. A number of challenges limit women’s enjoyment of the full benefits from NWFPs exploitation, the overriding problem being their inadequacy (in quantity and/or quality). In this paper we discuss these commonly utilized and managed NWFPs plant species in Mbooni and their potential contribution to improved livelihoods and sustainable development in Mbooni, Kenya and Sub-Saharan Africa (SSA) in general.     

Understanding deforestation in montane and lowland forests of the Colombian Andes

Colombian Andean forests cover nine million ha. These forests provide an informative case study of mountain deforestation in South America. They are surrounded by tropical lowland forests, and they host most of the country’s human population. This study evaluates the relative importance of human and natural variables in deforestation of the Colombian Andes between 1985 and 2005 using remote sensing methods, geographic information system (GIS) technology and general linear models (GLM). The following factors affected the annual deforestation in the region positively: forced population migration, unsatisfied basic needs, economic activity, crops, pastures, illicit crops, protected areas and slope. Factors having a negative effect were tenure of small land parcels, road density, water scarcity and mean temperature. The results of this study also provide insight into the differences between the dynamics of lowland forests and those of montane forests. Montane forests had a lower annual rate of deforestation than did forests in the lowlands. Socio-economic, demographic and biophysical factors explain overall deforestation rates for the region. However, when altitude variation is taken into account, intraregional differences in the Andes become evident. Deforestation processes differ between those areas adjacent to the high Andean valleys where most of the country’s population concentrates and those areas in the tropical lowlands north, west and east of the Andean chain. Differences between lowland and montane forest dynamics are due partly to the accessibility of forests and differences in wealth and economic activities. In montane forests, deforestation is positively influenced by economic activity, the presence of protected areas and higher slopes. Deforestation in montane forests is negatively affected by tenure of small land parcels, road density, water scarcity and mean temperature. Lowland deforestation rates are more closely related to rural population, pasture percentage, crops, protected areas and temperature. Our results suggest that montane forests appear to be in a more advanced stage of colonisation and economic development, whereas lowland forests are closer to the colonisation frontier and to rapidly growing colonist populations. This study reinforces the idea that although the most common tropical drivers of deforestation are found in the Andes, these drivers operate differently when intraregional differences are considered.     

Consumptive values and local perception of dry forest decline in Burkina Faso,West Africa

Traditional ecological knowledge and local experience of resource management and the usefulness of plant species can make important contributions to attempts to understand forest ecosystems and to develop effective sustainable management strategies for them. Therefore, the utilization of tree species by local people, their perceptions of changes in the surrounding forests, and suggested solutions for associated problems, were studied in the Sissili province of southern Burkina Faso. Information was collected through a combination of participatory rural appraisals, household interviews, and observational methods. Principal component analysis was used to analyze the consumptive values of woody species and their respective parts. A total of 82 species were identified, 90% of them were used for medicinal purposes, 78% for fodder, 73% for food, 67% for house construction, and 58% for wood carving. This suggests that forests play a key role in sustaining the rural livelihood and contributing to poverty reduction. The various stakeholders perceived that vegetation clearing for cultivation of cash crops (agribusiness) was the main driver of the change in forest cover. Species reported to be declining in the area included Parkia biglobosa, Pterocarpus erinaceus, Afzelia africana, Bombax costatum, Tamarindus indica, and Diospyros mespiliformis. Thus, a concerted effort should be made to manage the remaining natural forests in the country. Appropriate management strategies should be developed jointly by the local communities and external support groups to integrate the valuable local knowledge about forest species with the stakeholders’ suggestions in order to promote sustainable management of the region’s forest ecosystems.     

四川马边彝族自治县土地利用/覆被变化分析

采用基于最大似然法的监督分类方法对四川省马边彝族自治县1988年和2001年两期Landsate5 TM影像进行解译,利用单项土地利用动态指数〖WTBX〗（LUDI）、双向土地利用动态指数（Ki）以及土地利用类型转移矩阵（Cx×y）〖WTBZ〗等定量分析方法分析解译结果,得到马边县13年间土地利用/覆被动态及转移特征,并对可能的生态影响进行了分析预测。结果显示：①次生林面积增加,针叶林面积有所下降,灌草地被农田大量取代;②城镇及居民点和次生林的动态最为活跃,转入面积明显高于转出面积;③中山区和亚高山区林地构成发生变化,高山草甸面积有所萎缩,河谷区的阔叶林带被次生林大量取代,低山河谷区的土地破碎化程度增加。研究表明,13年间马边土地利用/覆被变化具有动态高、转换活跃、空间性强以及人为活动干扰影响明显等特点。其中,低山丘陵区的灌草坡大量被农地替代、中山区和亚高山区次生林面积扩大应该作为生态退化的信号加以重视。另外,气候变化对马边森林植被演替可能产生的影响应在今后进行深入的分析研究     

1982~2010年洞庭湖流域植被指数的变化及其与气候因子的相关分析

基于GIMMS 3 g、PAL、LTDR V3、FASIR及MODIS 5种不同的遥感影像数据,及洞庭湖流域30个气象站点的气温、降水和日照时数月值数据,采用逐像元一元线性回归模型,对比分析了在不同数据集背景下的植被变化趋势,并基于时间序列长度以及数据精度的考虑,选择GIMMS 3 g作为研究洞庭湖流域植被覆盖变化的基础数据集,进而利用相关系数和多元线性回归分析模型探讨流域植被覆盖变化与降水、气温、日照时数的关系。结果表明:(1)过去29 a间,流域GIMMS 3 g NDVI在时空尺度上均以增加趋势为主,1998~2000年出现最大的降低,以植被覆盖较好的山区减少最快;(2)去除年际变化趋势和季节性影响的NDVI与同期降水量距平、累积3个月气温距平值及同期日照时数距平值相关性程度最高;(3)统计意义上,降水量、气温和日照时数解释洞庭湖流域植被月NDVI变化的37%,日照时数对该流域NDVI变化的影响最大,其次为降水和气温;(4)在时间和空间范畴,生长季NDVI可以作为反映洞庭湖流域森林覆盖率变化的指标。     

Decline of woody vegetation in a saline landscape in the Groundnut Basin,Senegal

Several studies have documented that vegetation in the Sahel is highly dynamic and is affected by the prevailing climatic conditions, as well as by human use of the areas. However, little is known about vegetation dynamics in the large saline areas bordering the rivers of West Africa. Combining satellite imagery, the perception of local people and botanical information, this study investigated the vegetation dynamics and the drivers of vegetation changes in Fatick Province, Senegal. Satellite images showed a change in vegetation composition, i.e., a loss of tree cover and an increase in shrub cover, herbaceous cover and tans (highly saline areas with sparse vegetation). Although the trend was the same, the three villages had different vegetation histories. A survey of the woody vegetation showed that shrubs and young trees were dominating with relatively few large trees. Local people perceived a general decline of woody plants from 1993 to 2013. Among 60 species mentioned by local people, 90 % were declining and 10 % increasing. Together the three methods documented a decrease in density and diversity of the woody vegetation, mainly influenced by salinity and land use. The large numbers of young trees indicate a potential for regeneration of some, but not all, tree species. As many tree species appreciated by local people were reported to be declining, local communities have experienced a reduction of their natural resources. Based on villagers’ recommendations for improved vegetation management, we discuss possible contributions including reforestation, desalinization and environmental protection for restoration of the vegetation.     

Land cover changes in the Lachuá region,Guatemala: patterns,proximate causes,and underlying driving forces over the last 50 years

Identifying the patterns of land cover change (LCC) and their main proximate causes and underlying driving forces in tropical rainforests is an urgent task for designing adequate management and conservation policies. The Lachuá region maintains the largest lowland rainforest remnant in Guatemala, but it has been highly deforested and fragmented during the last decades. This is the first paper to describe the patterns of LCC and the associated political and socioeconomic factors in the region over the last 50 years. We estimated spatial and temporal variations in LCC from a random sample of 24 1-km² landscape plots during three time periods (1962–1987, 1987–2006, and 2006–2011) and evaluated how they were related to some important proximate causes and underlying driving forces. During the study period, 55 % of forest cover disappeared, at an annual rate of 1.6 %. The deforestation rate increased from 0.6 % (during the first study period) to 2.8 % (last period), but there was very high spatial variation. Landscape plots located outside conservation areas and close to roads lost between 80 and 100 % of forest cover, whereas the forest cover in landscapes located within protected areas remained intact during the study period. The establishment of new human settlements, roads, and annual crops was the main proximate cause during the first period, but during the second and third periods, open areas were mainly created to establish cattle pastures. Because ~75 % of forest cover has disappeared outside the protected areas, the conservation of this biodiversity hot spot will depend on the expansion of protected areas, and the promotion of forest regrowth and alternative biodiversity-friendly land uses in the landscape matrix.     

Forest dynamics in Mississippi, USA: a hybrid statistical and geospatial analysis

Understanding forest changes and its trajectory is important to develop policy options and future scenarios for climate analysis. This research is conducted to gain insights on secondary forests change using Mississippi, USA, as a case study. We investigate the spatial patterns and temporal dynamics of secondary forests at high resolution and examine the forces driving their changes. An extensive literature review is conducted to refine the conceptual framework of forest changes and identify the underlying key factors. Forest changes are quantified at high spatial (30-m) and temporal (biennial) resolutions, using time series remotely sensed data between 1984 and 2007. A number of geospatial and socioeconomic data were compiled to analyze the spatial variations of forest disturbances and their linkages to various socioeconomic, political, and biogeophysical factors. The results show that the secondary forests are highly dynamic and variable. Disturbances and regeneration occur continuously everywhere in a systematic and coordinated fashion. This pattern prevents an extensive disturbance and increases total forest cover. Market conditions (i.e., timber price) are the key predictor of the level and overall trend of forest disturbances. However, spatial patterns of forest dynamics cannot be explained by location-specific biophysical, socioeconomic, and policy factors identified in the literature. They can best be described by the ecological characteristics of the forests (i.e., the forest type and age distribution), which have a clear economic linkage. The research shows that regenerated forests frequently experience loss and gain of their extent, and their ecological characteristics change drastically on a short-term basis. These results point out challenges and opportunities in forest management and policy with regard to reforestation.     

川西亚高山植被恢复过程中的土壤和地被物水源涵养能力评价

运用以空间代替时间，以糙野青茅草地、柳树灌丛、白桦林、混交林、冷杉林为植物自然恢复的序列，采用环刀法和实地调查-水浸法研究了川西亚高山植被恢复过程中土壤和地被物的持水能力。结果表明：土壤容重随深度增加而加大、随植被恢复而降低；土壤持水能力随深度增加而降低、随植被恢复而增加，表现为混交林>冷杉林>柳树灌丛>白桦林>草地；地被物储量及其持水能力随植被恢复极显著增加，其组成由草地的凋落物为主到冷杉林时以苔藓为主；生态系统土壤和地被物的持水能力随着恢复而显著提高，表现为混交林>冷杉林>柳树灌丛>白桦林>草地。因此，亚高山植被自然恢复能显著增加区域生态系统的土壤和地被物持水，适度增加阔叶树亦有利于促进川西亚高山恢复植被的土壤持水     

金沙江干热河谷几种引进树种人工植被的生态学研究

采用标准木法和收获法,对金沙江元谋干热河谷几种引进树种的人工植被（即赤桉×新银合欢混交林、赤桉纯林、新银合欢纯林和印楝纯林）各层植被生物量与天然次生植被（坡柳-扭黄茅灌草丛）进行了比较研究,同时对各类植被的物种组成和物种多样性进行了比较分析。结果表明：（1）采用引进树种人工恢复的植被积累了大量生物质,总生物量大小依次为：赤桉×新银合欢混交林（4491 t/hm2）>新银合欢纯林（3991 t/hm2）>赤桉纯林（3857 t/ hm2）>印楝纯林（1306 t/hm2）>天然次生林（935 t/ hm2）。人工恢复植被生物量主要集中在乔木层,天然次生植被生物量主要集中在灌木、草本和凋落物层。（2）人工恢复植被的物种数均少于天然次生植被,而且不同植被的物种数和物种组成也存在差异。（3）各植被的Shannon wiener多样性指数和Margalef丰富度指数均表现为：印楝纯林>坡柳-扭黄茅灌草丛>赤桉纯林>赤桉×新银合欢混交林。在Alatato均匀度指数方面,各人工植被之间的差异不大,但人工植被与天然次生植被之间有显著差异。〖     

Communities of trees along a tropical forest restoration gradient

Increasing rates of deforestation in tropical forests have been linked to agriculturalists. A critical concern generating debate is how well communities of trees recover into a more species rich ecosystem after restoration planting. The aim of the study was to evaluate the pattern of recovery of communities of tree, assess the influence of Acanthus pubescens, Lantana camara and Pennisetum purpureum, on the recovery as well as how restoration planting facilitates recruitment of other native tree seedlings along a gradient of forest restoration in Kibale National Park, Uganda after evictions of illegal settlers. We studied six restoration forests ranging in age from 3 to 16 years, naturally regenerating and three primary forests. Our results showed that recovery with natural regeneration was more effective than restoration planting although the latter enhanced recruitment of other native tree seedling. Tree recovery was generally correlated with age so that species density and diversity increased although at different rates. A reverse pattern was found for dominance but no clear pattern was found for tree density (individual/ha). Communities of tree showed directional patterns of change however community composition were still distinct among the different forests. A. pubescens, L. camara and P. purpureum negatively correlated with species density, tree density and diversity but a positive correlation was found for dominance. Restoration planting can reestablish forests with high species density, tree density and diversity, but this is dependent on age and the extent of the herbs, grasses and shrubs cover in tropical forests.