Edge effects for songbirds vary with forest productivity

We hypothesized that edge density more strongly influences species abundances in more productive environments. To test this hypothesis we collected songbird point count data across broad biophysical gradients and gradients in forest patch edge density in the west and east slopes of the Cascade Mountains of Oregon and Washington, U.S.A., which differ in ecological productivity. We then analyzed bird response (75 species) at both the species and community level to gradients in edge density (m/ha) of open and closed-canopy forest within 1-km radius landscapes. We found that (1) differences in vegetation and structural conditions between open and closed-canopy stands were significantly greater at a highly productive landscape than a landscape with intermediate levels of productivity; (2) more bird species responded to changes in edge density in more productive west-slope Cascade forests than less productive east-side Cascade forests; (3) pooled abundance data from both sites showed that 25 of the 60 most abundant bird species responded significantly to the interaction between forest productivity and changes in landscape-level edge density; and, (4) at the community level, ordinations showed that bird community similarity in the productive west-slope Cascade forests differed across low and high levels of edge density whereas no such differentiation occurred in harsh, east-side Cascade forests. These results provide some of the first evidence supporting the hypothesis that edge effects are more pronounced in productive west-side forests where higher levels of edge density benefit generalist and open-canopy species while negatively influencing closed-canopy species. Consequently, forest management aimed at supporting species diversity will be most effective if tailored to ecosystem productivity.     

Capercaillie (Tetrao urogallus) Lekking sites in fragmented Finnish forest landscape

The location of Capercaillie lekking sites was compared in forest mosaics of different level of fragmentation. In north Finland the stand characteristics of the lekking sites did not differ from those of randomly selected stands in the 1950s judged from forestry maps and stand registers. In the 1980s, when forestry had considerably altered stand structure, lekking stands were older, larger and had a higher timber volume than random stands. These features evenly changed from the lek centre to the distance of 4 km, to which distance the adjacent areas were assessed. Southern and central Finnish analyses, based on topographic maps, showed that the proportion of forest distinctly decreased with increasing distance from a lek centre, up to a distance of 1–1.5 km. The average patch size of lekking stands were largest in the north (where both cut areas and remaining stands are large) and smallest in central Finland dominated by fine‐grained forest landscape. The results are discussed in terms of landscape ecology and forestry planning.     

Effects of Forest Management on Field Layer Vegetation: A Comparison Between Finnish and Russian Karelia

The effects of forest management on the field layer vegetation were compared between Finnish and Russian Karelia in a total of 46 mature stands representing pine, spruce and deciduous forests. In Finland, the number of species was slightly higher in each forest type. Many grassland species, such as Galium boreale , Lathyrus pratensis , and Veronica officinalis , were more abundant in Finnish deciduous stands (14.4 species, mean cover 15.8%) than in Russian stands (9.6 species, mean cover 11.5%). Dwarf shrubs, such as Calluna vulgaris (mean cover: Fin 3.3%, Rus 7.7%) and Vaccinium vitis-idaea (Fin 25.0%, Rus 26.9%) in pine stands, and Vaccinium myrtillus (Fin 22.9%, Rus 31.5%) in spruce stands, were more abundant in Russia. Ferns and graminoids exhibited no differences between the two countries. The observed differences were likely to result from the lower tree stand density, more extensive fragmentation and fertilisation of forests in Finland, the higher frequency of forest fires and more intensive grazing in Russian forests, and from differences in natural conditions between Finnish and Russian Karelia.     

广东西樵山国家森林公园景观格局分析及优化

城郊森林公园是提升大众福祉、发挥生态功能的载体。以广东西樵山国家森林公园为研究对象，运用 ArcGIS 软件和Fragstats软件对其景观格局进行分析。结果表明，风景林是公园景观的基质（PLAND =67.84%），道路廊道将其与用材林、建筑和水体3种主要景观类型进行串联；公园各景观类型的破碎化程度不同，斑块形状均较为规则（MSI值为1.41~2.12；MPFD值为1.10~1.24）；公园的景观多样性较低（SHDI=1.31），斑块空间分布不均（SHEI=0.53），斑块形状较为复杂（LSI=22.83），各功能分区的格局特征差异明显。城郊森林公园的经营应严格控制人为干扰影响，提高公园景观多样性，注重斑块类型、功能分区和整体景观格局的优化。     

Landscape pattern and diversity of natural secondary forests in the eastern mountainous region, northeast China： A case study of Mao＇ershan region in HeUongjiang Province

Mao‘ershan region is a representative natural secondary forested region in the eastern mountainous region, northeast of China. Under the support of ARC/INFO, the landscape pattern and landscape diversity of Mao‘erhshan region were sudied by combining the forest type map (1:10 000), which was drawn from the aerial photographs (1999), field investigation and land utilization map (1:10 000). The selected indices included patch number, patch size, patch density index, richness index,dominance index, evenness index and diversity index. The results showed that the landscape dominant forest type in Mao‘ershan region was softwood broad-leaved forest. In all landscape types, the average patch area of natural secondary forests was bigger than that of artificial forest. The patch density index of each landscape formed in artificial forest was higher than that of natural secondary forest. The landscape diversity index and landscape evenness index of natural forest were highest, the landscape heterogeneity was also, but the landscape dominance was lower. In natural forest, the control effects of landscape elements on landscape-structure, function and its change were weakened. The artificial forest was on the contrary.     

Differences in the forest landscape structure along the Finnish–Russian border in southern Karelia

Abstract

This study describes forest landscape fragmentation and connectivity along the Finnish–Russian border near the Karelian Isthmus. The landscape pattern was analysed using classification data based on Landsat ETM+ and Landsat TM images in combination with systematic surveys in Finland (Finnish National Forest Inventory) (n=546) and the authors’ own fieldwork data in Russia (n=101). On the Finnish side the forest patches are significantly smaller than on the Russian side. In addition, the Finnish forests landscape is more scattered and distances between patches of the same forest type are longer. The Russian side is more dominated by broadleaved and mixed forest stands. The disparities are due to differences in forestry policy and traditions of forest practices. The growing conditions of the areas are similar. The habitat fragmentation and habitat connectivity are important issues because the Karelian Isthmus is one of three main corridors and migrating routes connecting large Russian boreal taiga forests and their fauna and flora with Finnish isolated boreal forests.     

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.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Deforestation and fragmentation of Chaco dry forest in NW Argentina (1972–2007)

The sustained increase in the global food demand has favoured the recent expansion of industrial agriculture into neotropical dry forest ecosystems, with resulting changes in their extent and spatial configuration. Based on Landsat satellite images, we analyzed changes in forest cover and landscape configuration over an area of 600 by 100 km located in NW Argentina (Tucumán and Salta provinces) in four periods between 1972 and 2007. The study area, one of the most active deforestation frontiers of South American dry forest, was divided into six relatively homogeneous sectors in terms of land property structure and biophysical characteristics. During the study period 1.4 millions hectares of dry forest were cleared. Deforestation started in the 1970s as a result of technological changes and increasing rainfall; continued (with spatial and temporal fluctuations) during the 1980s and 1990s in association to the sustained global demand of soybean, and was accelerated (to ca. 100,000 ha year⁻¹) between 2001 and 2007 following the global increase in commodity prices, and the national peso devaluation. We described the landscape structure using eight landscape indices, summarized as one synthesis value: the Euclidian distance across the seven dimensions from a theoretical non-fragmented situation. In areas with soil limitations deforestation resulted in relatively stable, highly fragmented landscapes. In contrast, the sites with regional coarser-scale limitations (rainfall), deforestation produced a less fragmented landscape where agriculture concentrates in sites with high rainfall. Sites with no limitations for agriculture tend to a largely deforested landscape with few small and poorly connected forest patches. The land properties size seems to influence some indices of fragmentation, but the synthetic index of fragmentation suggests an overall convergence of fragmentation patterns towards a similar configuration across different biophysical and land tenure conditions.     

The effects of fragmentation on the susceptibility of a boreal forest ecosystem to wind damage

The clear cuts and seedling stands can speed up winds and may trigger blowdown at the edges of neighbour stands. Therefore, the height contrast of the neighbour stands and fragmentation at landscape level could be used to indicate the susceptibility of windthrow. In this study, we studied how forest fragmentation affects the susceptibility of a boreal forest ecosystem to wind damage, both at patch and landscape level based on theoretical computations. For this purpose we generated, based on real stand inventory data of a Finnish forest ecosystem, different landscape configurations of Scots pine and Norway spruce forests using Monte Carlo simulation. Thereafter, we applied a mechanistic wind damage model to predict the wind speeds needed for wind damage at forest edges. The fragmentation metrics of Contrast-Weighted Edge Density with three different height dissimilarity calculation methods were used to analyze the fragmentation at the landscape level.     

Assessing changes in forest fragmentation following infestation using time series Landsat imagery

The current epidemic of mountain pine beetle (Dendroctonus ponderosae Hopkins) in British Columbia, Canada, has impacted an area of over 13 million hectares presenting a considerable challenge to provincial forest resource managers. Remote sensing technologies offer a highly effective tool to monitor this impact due to very large areas involved and its ability to detect dead and dying tree crowns. Conventionally, change detection procedures based upon spectral values have been applied; however, analysis of landscape pattern changes associated with long-time series change detection approaches present opportunities for the generation of unique and ecologically important information. This study is focussed on the detection and monitoring of the shape and area characteristics of lodgepole pine stands during mountain pine beetle infestation to quantify the progression of forest fragmentation and related loss of landscape connectivity. A set of landscape pattern indices were applied to a set of images consisting of six Landsat satellite images spanning the period from 1993 to 2006. Our results indicate that the impacts of the mountain pine beetle infestation on forest spatial pattern consist of an increase in the number of patches, an increase in forest patch shape complexity, a reduction in forest patch size, an increase in forest patch isolation, and a decrease in interspersion. These findings demonstrate the unique information available from long-time series satellite imagery combined with pattern analysis to better understand the combined effects of insect infestation and forest salvage and harvesting.     

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.     

穆棱东北红豆杉国家级自然保护区景观斑块特征分析

运用景观空间数据分析软件计算相关景观指数,通过穆棱东北红豆杉国家级自然保护区内景观格局总体情况、斑块面积、周长、总数、分维数、破碎化、均匀度及多样性指数等分析,探讨保护区内森林景观空间格局。结果表明：针阔混交林、阔叶混交林、针叶混交林为保护区主要森林景观;景观要素的斑块面积、周长、数量差异极大;亚乔林及低矮阔叶乔木林景观宽块形状最复杂,且破碎化程度较高,针阔混交林景观斑块形状同样较复杂,但破碎化程度低,且成因不同;保护区总体景观多样性程度较低,景观类型分布不均匀,景观异质性较差。     

Identification of boreal forest stands with high herbaceous plant diversity using airborne laser scanning

Boreal forest stands with high herbaceous plant species diversity have been found to be one of the main habitats for many endangered species, but the locations and sizes of these herb-rich forest stands are not well known in many areas. Better identification of the stands could improve both their conservation and management. A new approach is proposed here for locating the mature herb-rich forest stands using airborne laser scanner (ALS) data and logistic regression, or the k-NN classifier. We show that ALS technology is capable of distinguishing the ecologically important herb-rich forests from those growing on less fertile site types, mainly on the basis of unique but quantifiable crown structure and vertical profile that characterise forests on high fertility sites. The study site, Koli National Park, is located on the border of the southern and middle boreal vegetation zones in Finland, and includes 63 herb-rich forest stands of varying sizes. The model and test data comprised 274 forest stands belonging to five forest site types varying from very fertile to poor. The best overall classification accuracy achieved with the k-NN method was 88.9%, the herb-rich forests being classified correctly in 65.0% of cases and the other forest site types in 95.7%. The best overall classification accuracy achieved with logistic regression was 85.6%, being 55.0% for the herb-rich forests and 94.3% for the other forest site types. Both methods demonstrated promising potential for separating herb-rich forests from other forest site types, although slightly better results were obtained with the non-parametric k-NN method, which was capable of utilising a higher number of explanatory variables. It is concluded that ALS-based data analysis techniques are applicable to the detection of mature boreal herb-rich forests in large-scale forest inventories.     

海南昌化江流域天然林景观格局演变研究

以遥感影像为基础数据源,通过面向对象的影像分析软件Ecognition和ArcGIS软件,解译提取昌化江流域1995年、2000年和2007年天然林信息,以Fragstats景观格局分析软件为景观指数计算工具,选择景观斑块形状指数、景观斑块数量破碎化指数、景观斑块分维数指数等指标,对昌化江流域天然林空间格局的动态变化进行研究。结果表明:1995年、2000年和2007年昌化江流域天然林总面积分别为1 431.38 km2,2 143.17 km2和1 487.98km2,天然林景观空间格局发生了波浪形变化,目前天然林破坏严重。分析结果为天然林的保护与恢复提供了科学依据。     

汤旺河森林景观格局与地类景观要素动态分析

运用地理信息系统分析软件ArcGIS9和Frgastats3．3,处理1992年、2012年汤旺河林业局林相图,并用所得到的景观总面积、斑块密度、平均斑块面积、边缘密度、平均斑块分维度、香农多样性、香农均匀度等10个景观指数对汤旺河林业局森林景观格局和地类景观要素变化进行了研究,结果表明：汤旺河林业局连接度减弱、蔓延度降低、景观破碎化程加深。     

Inclusion of forest harvest legacies, forest type, and regeneration spatial patterns in updated forest maps: A comparison of mapping results

In Maine and other heavily forested states, existing land cover maps quickly become dated due to forest harvesting and land use conversion; therefore, these maps may not adequately reflect landscape properties and patterns relevant to current resource management and ecosystem studies. By updating an older land cover product (the 1993 Maine GAP map) using Landsat imagery and established forest change detection techniques, we demonstrate a practical and accurate means of providing contemporary, spatially explicit forest cover data needed to quantify landscape change. For a 1.8 million hectares study area in northern Maine, we quantify the accuracy of forest harvest classes and compare mapped harvest and regeneration area between the 2004 GAP update product and the 2004 Maine Landcover Dataset (MeLCD), a map recently developed in coordination with the 2001 National Land-Cover Database (NLCD). For the period 1995–2004, the overall harvest/non-harvest accuracy of the GAP update map is 87.5%, compared to 62.1% for the MeLCD. Producer and user accuracy for harvest detection is 92.4% and 89.7%, respectively for the GAP update, and 48.8% and 92.5% for the MeLCD. Mapped harvest area differs considerably, reflecting a systematic under-representation of recent harvest activity on the part of the MeLCD. By integrating older land cover data, the GAP update retains the forest disturbance legacies of the late 1970s through the early 1990s while simultaneously depicting 2004 forest composition for harvested and regenerating stands. In contrast, the MeLCD (and 2001 NLCD) over-represents the area and connectivity of older forest (undisturbed since the late 1970s), and provides no forest composition information for mapped forest regeneration. Systematic misclassification of forest age classes and harvest history has serious implications for studies focused on wildlife habitat modeling, forest inventory, and biomass or carbon stock estimation. We recommend the integration of older land cover data and time-series forest change detection for retention of harvest or disturbance classes when creating new forest and land cover maps.     

Effects of administrative land-use and technical land-form constraints on timber production at the landscape level

Abstract

This study quantified, across a landscape in Eastern Finland, the influence of administrative land-use and technical land-form constraints on timber production. Spatially explicit data about the nature conservation areas, land use plans and steep slopes were integrated with Multi-source National Forest Inventory (MS-NFI) data. The Finnish forestry model MELA was used in the calculations related to updating forest data and estimating different scenarios of timber production with and without constraints. In the study area, the annual volume of maximum sustainable cutting removal defined for the next 30 years was decreased by one-third due to restrictions. The presented approach could be used, for example, to assess timber availability at the landscape level. Future challenges include ensuring the compatibility of spatially explicit data obtained from different sources, identifying the feasibility of forest management operations in the restricted area, and incorporating near-nature forest management operations in the forest planning system in order to estimate the timber production.     

Long-term changes in two boreal landscapes with different management histories

Abstract

Forest fragmentation increases the amount of edge habitats in landscape. Despite the profound ecological influences that edges may have, the patterns and processes of edge formation have largely remained unexplored. The aim of this study was to find answers to three questions: (1) How have the landscape structure and composition, as measured by different successional stages, changed over a period of about 50years in forested landscapes in southern Finland? (2) What are the differences in the amount of edge and interior habitat between successive years? (3) How does the forest ownership, state or private, affect the prevalence of edges? Digitized aerial photographs taken in 1941 and 1944 (period1), 1969 (period2) and 1997 (period3) were used to study the prevalence of different successional stages, area of interior mature forest and edge habitats in two nearby 10km² forest areas with private and state ownership, respectively. The forest composition was similar in the two forest areas, with mature forests being replaced by younger development stages. The area of interior mature forest decreased dramatically from period1 to period2. Assuming an edge width of 100m, the proportion of edge habitat increased from 30% to 61% in the state forest and from 26% to 76% in private forest. The detected changes and their possible consequences to species suggest that management of different types of edges and converging edges should receive considerable attention in the future.     

Landscape pattern and fragmentation of natural secondary forests in the eastern mountainous region, northeast China: A case study of Mao'ershan forests in Heilongjiang Province

Mao'ershan region is a representative natural secondary forested region in the eastern mountainous region, northeast of China. Under the support of ARC/INFO and GIS technology, the landscape shape and fragment indices of Mao'ershan experimental plantation were studied by combining the forest type map (1∶10000), which was drawn from the aerial photographs (1999), field investigation (1999) and soil utilized map (1∶10000). The results showed that the shape index and shape fragment index of natural landscape were higher than those of artificial landscapes and landscape patch fragment index depended on the number of patches. The natural forest had complex shape, suffering little jamming, and its shape index was higher than that of artificial forest. The manual controlled landscape (e.g. nursery, cropland and cutting blank) had regular shape, and its shape index was smaller. The fragment index of patches in natural forest was higher than that of artificial forest. The soft broad-leaved had the highest fragment index of patch amount. Foundation item: This paper was supported by National Key Technologies P&D Program of China during the 10^th Five-Year Plan Period (2002BA515B040). Biography: LI Shu-juan (1977-), female, Lecturer in Ocean University of China, Qingdao 266003, P. R. China. Responsible editor: Zhu Hong