Tree structure and diversity of lowland Atlantic forest fragments: comparison of disturbed and undisturbed remnants

This study describes the tree community structure of three moist lowland Atlantic Forest fragments in Rio de Janeiro State, southeastern Brazil. Two fragments were disturbed and an undisturbed one was used as reference. Our hypothesis was that disturbed fragments show distinct structural patterns in comparison with undisturbed stands due to past disturbance practices and forest fragmentation. Four 100 ×5 m sampling plots were demarcated in each fragment and all live and dead trees with DBH C 5 cm were located, measured and identified. The results supported our hypothesis, due to the high values found for standing dead trees, an increase of dominance of a few pioneer species, lower values of large trees and species richness in disturbed fragments in comparison with the undisturbed one. The advanced fragmentation process in the Southern Brazilian lowland areas and the high species richness in undisturbed areas highlight these forest fragments as priority areas for conservation and management.     

Reduced ant diversity along a habitat regeneration gradient in the southern Brazilian Atlantic Forest

This study evaluates the response of the ant communities along a habitat regeneration gradient in the south Atlantic Forest comparing it with the ant fauna from a mature forest at the same biome. The survey was conducted according to standard collecting protocols, employing sardine baits and mini-Winkler apparatuses. The structure of the ground and litter-foraging ant community was compared in five habitats, representing a regeneration gradient within the Atlantic Forest. Furthermore, the composition of the leaf-litter ant fauna and the species richness were compared between the regeneration gradient and an area of mature forest. The results showed a higher number of leaf-litter ant species in the mature forest in comparison with the regeneration gradient habitat, as well a distinct species composition. There was a significant loss of ant diversity in the regrowth forest, compared to the mature Atlantic Forest. The composition of the ground-dwelling ant fauna does not consistently separate the sites of forest succession; but a gradient of ant species richness and composition was revealed when the leaf-litter ant fauna data set was included in the analysis. In this sense, the leaf-litter ant fauna is an important segment to characterize habitats also playing an important rule as bio-indicators. The data suggest that only primary forests (our data) and old secondary forests (in litt.) are capable of maintaining a substantial proportion of the biodiversity in areas of the Atlantic Forest.     

Assessing forest fragmentation in north-western Himalaya: a case study from Ranikhet forest range,Uttarakhand, India

The northwestern Himalaya harbors high levels of biodiversity due to its unique topography, climatic conditions and heterogeneity. Forest fragmentation is one of the major threats causing a decline in biodiversity in the Himalayan region. We assesses forest fragmentation and changes in land use land cover(LULC) patterns using multi-temporal satellite data over a time span of four decades(1976–2013). Fragmentation analysis using the Landscape Fragmentation Tool(LFT) reveals a decrease in core and edge areas by 14 and 2.3 %, respectively; while an increase in non-forest, patch area and perforation area by 2.1, 0.4, and 14 %, respectively. The LULC dynamics show that the areas under dense forest and scrub forest have decreased by 2.8 % and 1.9 %, respectively; and there is an increase in open forest, crop land and fallow land area by 2.6, 1.7 and 2.1 %, respectively. The quantification of landscape heterogeneity is undertaken with the help of landscape metrics computed using FRAGSTATS at class and landscape level, showing signs of increased fragmentation. Our study provides baseline database that can support the future biodiversity conservation and sustainable forest management initiatives.     

Hazel Grouse occurrence in fragmented forests: habitat quantity and configuration is more important than quality

Forest fragmentation has led to a decline in the population of many forest specialists, especially those with limited dispersal abilities. However, some of these species also occur in fragmented forests, and their response to fragmentation is crucial to understand the impact of this process in maintaining forest biodiversity. The objective of this study was to investigate the effects of habitat quality, quantity and configuration on the occurrence of Hazel Grouse as the model species. Studies were performed in the Carpathian Foothills (900?km², 15?% forested). Between 2000 and 2010, Hazel Grouse were detected in 25 out of 53 forest patches with high repeatability over time. Among the indices of habitat quality, the most important factors were the presence of bilberries, clearings and pioneer trees. Greater number and length of valleys also had a positive effect on the occurrence of grouse. All habitat quantity and landscape configuration variables influenced the presence of grouse positively (related to forest connectivity) or negatively (related to forest isolation). Among the explanatory variables considered, habitat quantity and landscape variables were much more important in explaining the occurrence of Hazel Grouse than variables related to habitat quality. The study shows that habitat acreage and its connectivity are crucial for the conservation and management of Hazel Grouse populations in fragmented landscapes, and therefore, it is necessary to sustain wooded corridors between larger forest patches.     

Forest fragmentation,structure, and age characteristics as a legacy of forest management

The combination of forest inventory and satellite-derived landscape composition and structure provides otherwise unavailable information on regional forest conditions and enables investigation of the cumulative effects of forest management over time. Forest pattern results from a range of both natural and anthropogenic factors. This study characterizes the forest pattern of Vancouver Island, British Columbia (>32,000 km²) at the watershed scale, using new national datasets of Canadian forest composition and fragmentation, and relating these to forest inventory-derived age structure. Vancouver Island is extensively forested, possessing highly valuable and productive forests, and is managed to meet a range of stakeholder interests. Forest fragmentation metrics were derived from a satellite-derived, 25-m spatial resolution land cover map (i.e., grain) to represent patterns within 1 km analysis units (i.e., extent) for the entire forested area of Canada. We summarized forest fragmentation island-wide and compared trends between forest-dominated (>85% forest) and less-forested (<85% forest) watersheds. We also explored these patterns with partial canonical correspondence analyses to determine the independent and shared relationships of landscape composition, forest fragmentation, and spatial variables with forest age structure.     

Effects of roads,topography, and land use on forest cover dynamics in the Brazilian Atlantic Forest

Roads and topography can determine patterns of land use and distribution of forest cover, particularly in tropical regions. We evaluated how road density, land use, and topography affected forest fragmentation, deforestation and forest regrowth in a Brazilian Atlantic Forest region near the city of São Paulo. We mapped roads and land use/land cover for three years (1962, 1981 and 2000) from historical aerial photographs, and summarized the distribution of roads, land use/land cover and topography within a grid of 94 non-overlapping 100 ha squares. We used generalized least squares regression models for data analysis. Our models showed that forest fragmentation and deforestation depended on topography, land use and road density, whereas forest regrowth depended primarily on land use. However, the relationships between these variables and forest dynamics changed in the two studied periods; land use and slope were the strongest predictors from 1962 to 1981, and past (1962) road density and land use were the strongest predictors for the following period (1981–2000). Roads had the strongest relationship with deforestation and forest fragmentation when the expansions of agriculture and buildings were limited to already deforested areas, and when there was a rapid expansion of development, under influence of São Paulo city. Furthermore, the past (1962) road network was more important than the recent road network (1981) when explaining forest dynamics between 1981 and 2000, suggesting a long-term effect of roads. Roads are permanent scars on the landscape and facilitate deforestation and forest fragmentation due to increased accessibility and land valorization, which control land-use and land-cover dynamics. Topography directly affected deforestation, agriculture and road expansion, mainly between 1962 and 1981. Forest are thus in peril where there are more roads, and long-term conservation strategies should consider ways to mitigate roads as permanent landscape features and drivers facilitators of deforestation and forest fragmentation.     

Deforestation and forest fragmentation in the highlands of Eastern Ghats,India

Tropical forest cover change along with increasing fragmentation has detrimental effects on the global biodiversity. In the current study change in both forest cover and fragmentation of Koraput district have been assessed in the past three decades(1987-2017) and future decade(2017-2027), which has been modelled using logistic regression showing a gradual decrease in the forest cover and increase in fragmentation. The long term deforestation rates from 1987 to 2017(current period) and from 1987 to 2027(predicted period) were found to be-0.018 and-0.012, respectively. Out of the total geographical area, 2027 number of grids(1 km2) out of 8856 grids were found to have shown extinction of forest in the study period. The conversion of forested lands into other land uses has been one of the major causes of deforestation in Koraput, especially because of the increasing mining activities and establishment of three major industries namely National Aluminium Company(NALCO), Damanjodi, Hindustan Aeronautics Limited(HAL), Sunabeda and Ballarpur Industries Limited(BILT). The forest fragmentation reveals a negative trend, recording highest conversion from large core fragments to edge(191.33 km2) and the predicted period has also shown the same trend of negative change, which poses serious danger to the structure of the forests. Out of all the landscape matrices calculated, number of patches will increase to 214 in 2027 from 93 in 1987. In the test between geographically weighted regression(GWR) and ordinary least square regression(OLS), GWR was the better fit model for drawing a spatial relationship between forest cover and fragmentation changes. The study confirmed that the forest cover change has impacted the forest fragmentation in the study area. The programmes like REDD + should be implemented along with the experiences of Community Forest Management and the joint forest management should be intensified at community level in order to develop better management practices to conserve habitats in biodiversity rich areas.     

Characterizing changes in land cover and forest fragmentation from multitemporal Landsat observations (1993-2018)in the Dhorpatan Hunting Reserve,Nepal

Natural forces and anthropogenic activities greatly alter land cover,deteriorate or alleviate forest frag-mentation and affect biodiversity.Thus land cover and forest fragmentation dynamics have become a focus of concern for natural resource management agencies and biodiversity con-servation communities.However,there are few land cover datasets and forest fragmentation information available for the Dhorpatan Hunting Reserve (DHR) of Nepal to develop targeted biodiversity conservation plans.In this study,these gaps were filled by characterizing land cover and forest frag-mentation trends in the DHR.Using five Landsat images between 1993 and 2018,a support vector machine algorithm was applied to classify six land cover classes:forest,grass-lands,barren lands,agricultural and built-up areas,water bodies,and snow and glaciers.Subsequently,two landscape process models and four landscape metrics were used to depict the forest fragmentation situations.Results showed that forest cover increased from 39.4％ in 1993 to 39.8％ in 2018.Conversely,grasslands decreased from 38.2％ in 1993 to 36.9％ in 2018.The forest shrinkage was responsible for forest loss during the period,suggesting that the loss of for-est cover reduced the connectivity between forest and non-forested areas.Expansion was the dominant component of the forest restoration process,implying that it avoided the occurrence of isolated forests.The maximum value of edge density and perimeter area fractal dimension metrics and the minimum value of aggregation index were observed in 2011,revealing that forests in this year were most fragmented.These specific observations from the current analysis can help local authorities and local communities,who are highly dependent on forest resources,to better develop local forest management and biodiversity conservation plans.     

南宁市青秀山风景名胜区景观多样性探析

景观多样性是生物多样性研究的主要内容之一,在生物多样性保护方面具有重要作用。本文运用景观生态学原理,借助地理信息系统技术,选取景观多样性、优势度、丰富度密度、均匀度、分离度、分维数等指数,分析了南宁市青秀山风景名胜区不同景观类型的空间分布特征。结果显示:整个研究区域的多样性丰富,各景观类型所占比例相对均匀,常绿阔叶林和马尾松林的破碎化程度较轻,经济林和农田等人工景观较破碎,表明人为干扰十分强烈。     

二郎山国家森林公园景观格局现状及分析

以景观多样性、景观优势度、均匀度、景观破碎度和分离等景观生态学分析指标,对雅安二郎山国家森林公园的景观空间格局进行评价。评价结果表明,公园具有良好的开展森林游憩和生态旅游的自然资源,经合理规划、科学开发和严格保护可以将其打造为以休闲观光、修学科考为主的森林生态旅游区。     

Contribution of large-scale forest inventories to biodiversity assessment and monitoring

Statistically-designed inventories and biodiversity monitoring programs are gaining relevance for biological conservation and natural resources management. Mandated periodic surveys provide unique opportunities to identify and satisfy natural resources management information needs. However, this is not an end in itself but rather is the beginning of a process that should lead to sound decision-making in biodiversity conservation. Forest inventories are currently evolving towards multipurpose resource surveys and are broadening their scope in several directions: (i) expansion of the target population to include non-traditional attributes such as trees outside the forest and urban forests; (ii) forest carbon pools and carbon sequestration estimation; (iii) assessment of forest health; and (iv) inclusion of additional variables such as biodiversity attributes that are not directly related to timber assessment and wood harvesting.There is an on-going debate regarding the role of forest inventories in biodiversity assessment and monitoring. This paper presents a review on the topic that aims at providing updated knowledge on the current contribution of forest inventories to the assessment and monitoring of forest biodiversity conditions on a large scale. Specific objectives are fourfold: (i) to highlight the types of forest biodiversity indicators that can be estimated from data collected in the framework of standard forest inventories and the implications of different sampling methods on the estimation of the indicators; (ii) to outline current possibilities for harmonized estimation of biodiversity indicators in Europe from National Forest Inventory data; (iii) to show the added value for forest biodiversity monitoring of framing biodiversity indicators into ecologically meaningful forest type units; and (iv) to examine the potential of forest inventory sample data for estimating landscape biodiversity metrics.     

人为干扰对秦岭火地塘林区景观格局的影响

以秦岭火地塘林区1958年、1988年和2004年森林资源二类调查资料为主要数据源,利用景观结构分析软件,分析比较该林区3个时期景观格局变化情况,探讨人为干扰对林区景观格局的影响。研究结果表明:火地塘林区高强度的外界干扰,增加了该地区的景观多样性和丰富度;干扰形成的次生森林景观比原生森林景观类型数增多,同时引起部分景观类型的消长变化;森林采伐后林区景观分维数降低,斑块形状变得规则,但随着植被的恢复,各景观类型的斑块形状逐渐复杂,景观的异质性增加。火地塘林区景观格局的变化充分反映了外界干扰对森林景观格局的影响,以及森林自主恢复的动态过程。     

基于森林资源二类调查的仁义镇森林景观格局及破碎化分析

通过景观的观点来审视城镇化的发展,是解决城市化过程中环境问题的新方法、新思路.采用2009年广西壮族自治区贺州市八步区仁义镇森林资源二类调查数据为基础数据,以GIS和Fragstats为技术支撑,从景观的组成结构、斑块特征等方面对研究区域景观的空间分布和结构特征进行了分析.结果表明,景观要素斑块中以小斑块所占比例最大,植被景观以乔木林和灌丛景观为主要类型.由于相对强烈的人类活动影响,区域内林业用地的景观破碎化程度较高.     

林窗研究进展

林窗作为一种经常发生的小规模干扰, 是森林循环更新的一种重要方式。林窗的形成影响着森林小生境、森林群落的组成和动态变化过程, 同时也影响着森林群落的结构和景观格局, 因此, 林窗对生物多样性的维持有着重要作用。文中从林窗的基础理论、概念、特征、林窗对生物多样性的影响等方面, 简要介绍了国内外的研究现状。     

滇西北滇金丝猴栖息地景观格局分析及其破碎化评价

生境丧失及破碎化已成为生物多样性最主要的威胁之一,对物种栖息地的景观格局进行分析及对其破碎化进行评价显得十分必要.对滇金丝猴栖息地景观格局和破碎化进行分析评价,结果表明,包括滇金丝猴适宜生境在内的森林面积占整个研究区面积的2/3,是该地区的主导景观类型;研究区景观格局已表现出一定程度的景观破碎化.滇金丝猴适宜生境面积为308 212.44 hm2,占整个研究区面积的18.86%.目前滇金丝猴适宜生境的破碎化程度较低,但仍需控制适宜生境已出现的景观破碎化,并通过生境恢复及廊道重建等措施加强对滇金丝猴的保护.     

Ecological thresholds in herb communities for the management of suburban fragmented forests

Fragmentation is a major cause of biodiversity loss. The relationship between fragmentation and biodiversity might be non-linear, due to the presence of ecological thresholds; however, the application of the threshold concept on the conservation of herb biodiversity has received limited attention. We assessed the relationship between a pool of woodland indicators and features of forest fragments (area, isolation, shape), and we evaluated whether ecological thresholds might provide guidelines for conservation. We performed our study in a human dominated area of northern Italy. In order to obtain a group of floristic indicators, we chose perennial herbs characteristic of the phytosociological syntaxa Fagetalia sylvaticae, Carpinion betuli and Erythronio-Carpinion, with suitable Landolt L and H index, obtained from previous relevés in reference and high-quality forests. Subsequently, we analyzed the relationship between richness of indicators and patch features recorded in a highly fragmented landscape. Generalized linear models showed that the number of forest indicators was positively related to fragment size and connectivity. Generalized Additive Models showed that the relationship between indicator richness and fragment size was non-linear, with the presence of two thresholds. The number of forest indicators increased until 35–40 ha; above this size the richness remained constant. Fragments above this threshold should be the target of conservation. Furthermore, the relationship between area and number of indicators was less steep in patches smaller than 1–1.5 ha. Patches between these two thresholds can be optimal targets of management actions, as small size increases can greatly improve their value for biodiversity. The identification of two thresholds in the relationship between patch area and indicators suggests an abrupt response to changing landscape features and provide quantitative targets for conservation.     

Endangered lowland oak forest steppe remnants keep unique bird species richness in Central Hungary

The biodiversity of natural or semi-natural native,old oak woodlands have high conservation impor-tance,especially in landscapes of monocultural forest plan-tations and arable fields.With a wider variety of microhabi-tats and foraging sources,such old oak forests can provide essential habitat for native forest bird communities.We con-ducted a study using bird point counts to compare the forest bird communities of old pedunculate oak (Quercus robur)remnants with native and non-native plantations in central Hungary in a landscape of mostly arable fields,settlements,and monocultural plantations.Avian surveys were carried out in old oak forest remnants,middle-aged oak,white pop-lar (Populus alba),hybrid poplar (Populus × euramericana),black locust (Robinia pseudoacacia),and pine (Pinus spp.)plantations.Fieldwork has been carried out in nine study sites,where all six habitat types were represented (with a few exceptions),to determine total abundance,species rich-ness,Shannon-Wiener diversity,species evenness,domi-nant and indicator species,and guild abundances.We found that old oak forest remnants were the most diverse habitats among the studied forest types,while hybrid poplar and pine plantations exhibited the lowest avian biodiversity.The avian guilds most sensitive to the loss of old oak forest remnants were ground foragers,bark foragers,cavity-nest-ers,residents,and Mediterranean migratory birds.Native habitats were more diverse than non-native plantations.Our results suggest that it is important to conserve all remaining high biodiversity old oak stands and to avoid clear-cutting of monocultural plantations in favour of practices such as mixed-species plantations,longer rotation lengths,or reten-tion forestry.     

Managing small remnants of native forest to increase biodiversity within plantation landscapes in the south west of Western Australia

Recent expansion of industrial-scale plantations into agricultural areas in Australia has the potential to assist biodiversity conservation by rehabilitating ecosystems at the landscape scale and reducing edge effects, isolation and disturbance within remnants of native vegetation. However, the efficient management of remnants for biodiversity within a plantation estate requires knowledge of both the causes and the consequences of remnant degradation. With this in mind, we examined key ecosystem features and processes relating to soil chemistry, decomposition, native tree health and regeneration and vertebrate abundance, within small forest remnants (1-4 ha) embedded within Eucalyptus globulus plantations in south west Western Australia. Soil nutrient enrichment was significantly associated with a scale of vegetation modification in order from: (1) intact forest, (2) remnants with native understorey (UDN), (3) remnants with exotic understorey (UDE), (4) plantation and (5) pasture. We propose that, in this region, UDE remnants will often remain in a degraded state even after plantation establishment and the cessation of stock grazing. This is due, in part, to more rapid rates of nutrient turnover sustaining higher nutrient availability in the soil following the replacement of ligneous understorey plants with annual ones. Cotton strips placed in surface soils were often disintegrated in UDE remnants and largely intact in UDN remnants, indicating that decomposition was accelerated in the former. Continued tree decline and regeneration failure within UDE remnants will also reinforce the UDE condition. There was less canopy seed set and little or no seedling establishment in UDE remnants compared to UDN remnants. Therefore, management interventions to assist native tree regeneration in UDE remnants are needed. Fauna trapping highlighted the desirability of retaining, and preferably restoring, small remnants in plantations. Small native mammals were found exclusively in remnants and fewer introduced Mus musculus were present in UDN remnants. Higher numbers of native lizards were found in UDN remnants, but this result was not significant (marginally).     

东莞市清溪亚公山森林公园规划

珠三角国家森林城市群建设带动了城郊型森林公园的发展和建设,东莞市清溪亚公山森林公园属于典型的城郊型森林公园,本章以东莞市清溪亚公山森林公园规划研究为例,分别从规划原则,规划目标、规划理念,旅游产品、旅游组织,植物景观,道路交通、道路绿化等方面内容,针对清溪亚公山森林公园的开放需求、资源特色及生态完整性,提出最适合东莞市清溪亚公山森林公园发展的途径,在保存、恢复、创造生物多样性与景观多样性的自然生态环境的基础上,建设成清溪镇生态安全格局的重要组成部分,成为周边城镇居民森林休闲旅游的新热点,运动休闲、康体娱乐的新空间,为东莞市清溪亚公山等城郊型森林公园规划提供了思路。