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1.
The three major threats to lichens in Sweden; forestry, air pollution, and structural changes in the agricultural landscape, are outlined. Forestry is the most serious. The majority of the red-listed lichens in forests are found in productive forests with a continuity in tree growth, but nearly 70% of the protected area in Sweden consists of alpine landscapes. Examples of important habitats with red-listed lichens are described, e.g. Alnus glutinosa marshes, alvar-vegetation, broad-leaved deciduous forests and different Picea abies forests. The use of selected indicator species of lichens and macrofungi (mainly red-listed species) in boreal coniferous forests provides information on continuity in tree growth of an area, and on earlier influences of forestry. Examples of indicator species for different types of forest are presented and discussed. In spite of the Swedish right of common accesso, collecting of lichens is forbidden without permission from the land-owner. Collecting in protected areas is allowed only with a permit obtained from the authorities.  相似文献   

2.
In this work, we studied the potentials offered by managed boreal forests and forestry to mitigate the climate change using forest‐based materials and energy in substituting fossil‐based materials (concrete and plastic) and energy (coal and oil). For this purpose, we calculated the net climate impacts (radiative forcing) of forest biomass production and utilization in the managed Finnish boreal forests (60°–70°N) over a 90‐year period based on integrated use forest ecosystem model simulations (on carbon sequestration and biomass production of forests) and life‐cycle assessment (LCA) tool. When studying the effects of management on the radiative forcing in a system integrating the carbon sink/sources dynamics in both biosystem and technosystem, the current forest management (baseline management) was used a reference management. Our results showed that the use of forest‐based materials and energy in substituting fossil‐based materials and energy would provide an effective option for mitigating climate change. The negative climate impacts could be further decreased by maintaining forest stocking higher over the rotation compared to the baseline management and by harvesting stumps and coarse roots in addition to logging residues in the final felling. However, the climate impacts varied substantially over time depending on the prevailing forest structure and biomass assortment (timber, energy biomass) used in substitution.  相似文献   

3.
4.
Effects of habitat loss and fragmentation on the behavior of individual organisms may have direct consequences on population viability in altered forest ecosystems. The American marten (Martes americana) is a forest specialist considered as one of the most sensitive species to human-induced disturbances. As some studies have shown that martens cannot tolerate >30–40% clear-cuts within their home range, we investigated marten space use (home range size and overlap) and habitat selection in landscapes fragmented by 2 different patterns of timber harvesting in the black spruce boreal forest: dispersed-cut landscapes (10–80 ha cut-blocks) and clustered-cut landscapes (50–200 ha cut-blocks). We installed radio-collars on female martens and determined 20 winter home ranges (100% minimum convex polygons and 60–90% kernels) in dispersed-cut (n = 8) and clustered-cut (n = 12) landscapes. Home range size was not related to the proportion of clear-cuts (i.e., habitat loss), but rather to the proportion of mixedwood stands 70–120 years old. However, female body condition was correlated to habitat condition inside their home ranges (i.e., amount of residual forest and recent clear-cuts). At the home range scale, we determined that mixedwood forests were also among the most used forest stands and the least used were recent clear-cuts and forested bogs, using resource selection functions. At the landscape scale, home ranges included more mixedwood forests than random polygons and marten high activity zones were composed of more residual forest and less human-induced disturbances (clear-cuts, edges, and roads). These results suggest that mixedwood forests, which occupy approximately 10% of the study area, play a critical role for martens in this conifer-dominated boreal landscape. We recommend permanent retention or special management considerations for these isolated stands, as harvesting mixedwood often leads to forest composition conversion that would reduce the availability of this highly used habitat. © The Wildlife Society, 2013  相似文献   

5.
周韩洁  杨入瑄  李嵘 《广西植物》2022,42(10):1694-1702
全球气候变化与人为活动等因素导致的生物多样性丧失,引起了全球各界对生物多样性保护的高度关注。传统生物多样性保护主要对物种、特有种、受威胁物种的种类组成及其分布模式开展研究,忽视了进化历史在生物多样性保护中的作用。云南是全球生物多样性热点地区的交汇区,生物多样性的保护历来受到广泛关注,为了更好地探讨云南生物多样性的保护措施,该研究以云南被子植物菊类分支物种为研究对象,基于物种间的演化关系,结合其地理分布,从进化历史的角度探讨物种、特有种、受威胁物种的种类组成及系统发育组成的分布格局,并整合自然保护地的空间分布,识别生物多样性的重点保护区域。结果表明:云南被子植物菊类分支的物种、特有种及受威胁物种的物种密度与系统发育多样性均显著正相关;通过零模型分析发现,由南向北标准化系统发育多样性逐渐降低;云南南部、东南部、西北部是云南被子植物菊类分支的重点保护区域,加强这些区域的保护,将最大化地保护生物多样性的进化历史和进化潜能。由此可见,融合进化历史信息的植物多样性格局分析不仅有助于更加深入地理解植物多样性的形成与演变,也为生物多样性保护策略的制定提供更多的思路。  相似文献   

6.
Lowland rainforests on Borneo are being degraded and lost at an alarming rate. Studies on mammals report species responding in various ways to habitat changes that occur in commercial forestry concessions. Here we draw together information on the relationship between the ecological, evolutionary, and biogeographic characteristics of selected Bornean non-volant mammals, and their response to timber harvesting and related impacts. Only a minority of species show markedly reduced densities after timber harvesting. Nonetheless there are many grounds for concern as various processes can, and often do, reduce the viability of wildlife populations. Our review of what we know, and of current understanding, helps predict mammalian dynamics and subsequent mammal-induced ecosystem changes in logged forests. We identify groups of mammal species that, although largely unstudied, are unlikely to tolerate the impacts associated with timber harvesting. On a positive note we find and suggest many relatively simple and low-cost ways in which concession management practices might be modified so as to improve the value of managed forests for wildlife conservation. Improving forest management can play a vital role in maintaining the rich biodiversity of Borneo’s tropical rain forests.  相似文献   

7.
Abstract The impacts of prescribed burning and timber harvesting on species diversity have been the subject of considerable debate. The temporal and spatial scale of these disturbances often presents major limitations to many studies. Here we present the medium‐term results of a planned long‐term study examining the impacts of logging and prescribed burning on the understorey floristic richness in shrubby dry sclerophyll forest in the south‐east of New South Wales, Australia. Generalized estimating equations were used to model the effect of environmental factors and disturbance variables on species richness at the coupe (~30 ha) and plot (~0.01 ha) scale. At the plot scale, fire effects on separate components of the vegetation were broadly consistent with other studies, with frequent fire resulting in a relative increase of species richness for species less than 1 m in height and a decline of larger species taller than this height. At the coupe scale, there was no decline in richness of larger shrub species, possibly owing to the spatial heterogeneity of fire frequency at this scale. Logging resulted in significantly greater species richness in the shrub layer, but had no significant effect on species richness in the ground layer. During the study period, there was a general decline in plant species richness at both coupe and plot scales which occurred independently of imposed management regimes. This is thought to be related to a natural succession following wildfire, and may be due to the absence of high‐intensity fire in the study area since 1973, or to an effect related to season of burning.  相似文献   

8.

Aim

Human activity is known to greatly influence species occurrences. In forest ecosystems, biodiversity is often believed to be influenced by two habitat characteristics: (1) forest continuity, related to a minimum length of time in a wooded state since a threshold date; and (2) stand maturity, related to the availability of late‐developmental‐forest attributes. In a context of ongoing global biodiversity loss, qualifying the effect of past and present human activity on forest ecosystems while taking into account variations in abiotic factors is of primary importance for conservation.

Location

Temperate mountain forests in the Northern Alps.

Method

Based upon a sampling design crossing forest continuity (ancient vs. Recent) and stand maturity (mature vs. overmature), and while controlling for the effect of two major environmental factors, soil and climate, we explored the individual response of saproxylic beetle, springtail, herbaceous plant and epiphytic macrolichen species to past and present human activity.

Results

Forest continuity influenced the occurrence of relatively few species, indicating that past land use had almost no legacy effect on the species occurring in the study forests today. In contrast, stand maturity had an overall positive effect on species occurrences. However, our results showed that species occurrences were more obviously influenced by abiotic conditions. Indeed, beyond the effect of continuity and maturity factors, the probability of presence of numerous species was best explained by climate and soil.

Main conclusions

Overall, we show that species occurrence was more influenced by stand maturity than by forest continuity, but also that site‐specific characteristics were of great importance in explaining the probability of presence for numerous species. In the ecological context of alpine forests, these findings emphasize the need to better control for climatic and edaphic conditions in order to (1) improve accuracy in predicting species occurrence and (2) better design areas of conservation interest.
  相似文献   

9.
Tree hollows are among the rarest habitats in today''s Central European managed forests but are considered key structures for high biodiversity in forests. To analyze and compare the effects of tree hollow characteristics and forest structure on diversity of saproxylic beetles in tree hollows in differently structured managed forests, we examined between 41 and 50 tree hollows in beech trees in each of three state forest management districts in Germany. During the two‐year study, we collected 283 saproxylic beetle species (5880 individuals; 22% threatened species), using emergence traps. At small spatial scales, the size of hollow entrance and the number of surrounding microhabitat structures positively influenced beetle diversity, while the stage of wood mould decomposition had a negative influence, across all three forest districts. We utilized forest inventory data to analyze the effects of forest structure in radii of 50–500 m around tree hollows on saproxylic beetle diversity in the hollows. At these larger spatial scales, the three forest management districts differed remarkably regarding the parameters that influenced saproxylic beetle diversity in tree hollows. In Ebrach, characterized by mostly deciduous trees, the amount of dead wood positively influenced beetle diversity. In the mostly coniferous Fichtelberg forest district, with highly isolated tree hollows, in contrast, only the proportion of beech trees around the focal tree hollows showed a positive influence on beetle diversity. In Kelheim, characterized by mixed forest stands, there were no significant relationships between forest structure and beetle diversity in tree hollows. In this study, the same local tree hollow parameters influenced saproxylic beetle diversity in all three study regions, while parameters of forest structure at larger spatial scales differed in their importance, depending on tree‐species composition.  相似文献   

10.
Saproxylic beetles constitute a significant proportion of boreal forest biodiversity. However, the long history of timber production in Fennoscandia has significantly reduced the availability of dead wood and is considered a threat to the conservation of saproxylic beetle assemblages. Therefore, since the mid‐1990s dead wood retention in harvested stands has formed an integral part of silvicultural practices. However, the contribution of this biodiversity‐orientated management approach to conserving saproxylic beetle assemblages in boreal forest landscapes that include production forestry remains largely untested. We examined differences in resident saproxylic beetle assemblages among stands under different management in a boreal forest landscape in Central Sweden, and in particular stands managed according to new conservation‐orientated practices. We also investigated the relationship between beetle diversity and forest stand characteristics. Bark of coarse woody debris (CWD) was sieved for beetles in old managed stands, unmanaged nature reserves, and set‐aside areas, and clear‐cut stands harvested according to certification guidelines [new forestry (NF) clear‐cuts]. All stand types contributed significantly to the total diversity of beetles found. While stand size, position, and distance to nearest reserve were unimportant, both the quality and the quantity of CWD in stands contributed significantly to explaining beetle abundance and species richness. This extends the previous findings for red‐listed invertebrates, and shows that heterogeneous substrate quality and a range of management practices are necessary to maintain saproxylic beetle diversity in boreal forest landscapes that include production forestry. The unique abiotic conditions in combination with the abundant and varied CWD associated with NF clear‐cuts form an important component of forest stand heterogeneity for saproxylic beetles. It is thus essential that sufficient, diverse, CWD is retained in managed boreal landscapes to ensure the conservation of boreal saproxylic beetle assemblages.  相似文献   

11.
Natural vegetation on the south-eastern coast of Peninsular India has now been reduced to patches, some of which are preserved as sacred groves. The plant biodiversity and population structure of woody plants (>20 cm girth at breast height; gbh) in two such groves, Oorani and Olagapuram, occurring on the north-west of Pondicherry have been analyzed. A total of 169 angiosperms have been enumerated from both sites. The Oorani grove (3.2 ha) had 74 flowering plant species distributed in 71 genera and 41 families; 30 of them are woody species, 8 are lianas and 4 are parasites. The Olagapuram grove (2.8 ha) was more species-rich with 136 species in 121 genera of 58 families; woody species were fewer (21) while 9 lianas and 3 parasites occurred. The vegetation structure indicates that the Oorani grove is a relic of tropical dry evergreen forest, whereas Olagapuram is reduced to a thorny woodland. The latter is heavily degraded as it has lost the status of a sacred grove because of its conversion to Eucalyptus plantations. The Oorani grove has an Amman temple in the centre. The attendant cultural rites and religious rituals have perpetuated the status of a sacred grove which has ensured the protection of the grove.  相似文献   

12.
人为干扰对风水林群落林下木本植物组成和多样性的影响   总被引:10,自引:0,他引:10  
华南地区的风水林是乡村聚落的一种特色林分, 具有守护村庄的象征意义。在过去的数百年中, 风水林在乡村的社会文化习俗的影响下而受到保护, 对当地的生物多样性保育有着重要作用。为揭示人为干扰对风水林的影响, 我们选择广东省东莞市大岭山镇同一林分起源的3个具有相似地形的风水林, 研究了在不同干扰强度下其林下木本植物种类组成和物种多样性。多响应置换过程(multi-response permutation procedures, MRPP)分析表明, 人为干扰显著改变了风水林林下木本植物组成(P = 0.001, A = 0.3886), 沿着干扰由弱至强的梯度呈现出中生性植物减少、阳生性植物递增的趋势。多样性指数变化趋势为重度干扰>中度干扰>轻度干扰, 但没有表现出统计学意义上的差异(P>0.05)。随着干扰强度的增大, 3个风水林群落相互间的林下物种相似性降低, 物种替代率呈增加趋势。双向聚类分析较好地反映出林下物种因受不同人为干扰强度影响而表现出在空间分布上的差异。指示种分析进一步确定了不同干扰强度下具有显著指示值(IV ≥60)的指示种。综合分析表明, 人为干扰有利于阳性物种在风水林内定居生长, 并明显地改变了林下木本植物组成, 但未能引起物种多样性的显著差异。此外, 找出对人为干扰产生关键生态响应的林下指示种, 对增进风水林的生物多样性保育以及生态系统管理有着重要的理论意义和实践价值。  相似文献   

13.
J. Liira  K. Kohv 《Plant biosystems》2013,147(1):211-220
Abstract

We quantified the effects of anthropogenic disturbances on the structure and biodiversity of boreal forests on acidic soils and created a statistically supported rational set of indicators to monitor the stand “naturalness”. For that, we surveyed various traits of tree layer, understory, herb layer, forest floor and several widely accepted biodiversity epiphytic indicators in 252 old‐aged boreal stands in Estonia, mostly dominated by Scots pine or Norway spruce. Multifactorial general linear model analyses showed that many forest characteristics and potential indicators were confounded by the gradient of soil productivity (reflected by the forest site type), local biogeographic gradients and also by stand age. Considering confounding effects, boreal forests in a near‐natural state have more large‐diameter trees (diameter at breast height >40 cm) and larger variety of diameter classes, higher proportion of spruce or deciduous trees, a larger amount of coarse woody debris in various stages, a more closed tree canopy and denser understory than managed mature forests. By increasing light availability above the field layer, forest management indirectly increases the coverage of herbs and lichens on the forest floor but reduces the alpha‐ and beta‐diversity of herbs and the proportion of graminoids. Human disturbances reduce the relative incidence of many commonly accepted biodiversity indicators such as indicator lichens, woodpeckers, wood‐dwelling insects or fungi on trees. The test for the predictive power of characteristics reacting on disturbance revealed that only a fraction of them appeared to be included in a diagnostic easy‐to‐apply set of indicators to assess the nature quality of boreal forest: the amount of dead wood, the proportion of deciduous trees, the presence of specially shaped trees and woodpeckers and, as an indicator of disturbances, the forest herb Melampyrum pratensis. Many of these indicators have already been implemented in practice.  相似文献   

14.
Fallen logs on the forest floor play an important role in tree seedling establishment in boreal and subalpine old-growth forests. We examined the abundance and state (degree of decay, moss coverage on their surfaces) of fallen logs on the forest floor and compared the occurrence of conifer seedlings and saplings on soil and fallen logs in old-growth evergreen boreal (Taisetsu) and subalpine (Yatsugatake) coniferous forest stands in Japan. The forest floors of both stands were covered mostly by soil, and fallen logs covered only a small proportion (4.5% in Taisetsu and 2.5% in Yatsugatake) of the forest floor. In both stands, no seedlings were found on freshly fallen logs. Both moss coverage and the occurrence of seedlings or saplings on fallen logs increased with decay in both stands. In Taisetsu, the occurrence of all conifer seedlings and saplings was, in general, restricted to fallen logs. In contrast, in Yatsugatake, Picea and Tsuga seedlings occurred much more frequently on fallen logs than on soil, whereas Abies seedlings and saplings became established on both soil and fallen logs. Seedlings were taller on decayed fallen logs, but taller saplings were rare on fallen logs in Yatsugatake. Results indicate that species characteristics, the condition of the fallen logs and environmental factors determine the preponderance of seedling and sapling establishment on fallen logs. The condition of fallen logs varies with the degree of decay, and fallen logs that function as seedling establishment sites on the forest floor are thought to be limited by time and space.  相似文献   

15.
Although conservation intervention has reversed the decline of some species, our success is outweighed by a much larger number of species moving towards extinction. Extinction risk modelling can identify correlates of risk and species not yet recognized to be threatened. Here, we use machine learning models to identify correlates of extinction risk in African terrestrial mammals using a set of variables belonging to four classes: species distribution state, human pressures, conservation response and species biology. We derived information on distribution state and human pressure from satellite-borne imagery. Variables in all four classes were identified as important predictors of extinction risk, and interactions were observed among variables in different classes (e.g. level of protection, human threats, species distribution ranges). Species biology had a key role in mediating the effect of external variables. The model was 90% accurate in classifying extinction risk status of species, but in a few cases the observed and modelled extinction risk mismatched. Species in this condition might suffer from an incorrect classification of extinction risk (hence require reassessment). An increased availability of satellite imagery combined with improved resolution and classification accuracy of the resulting maps will play a progressively greater role in conservation monitoring.  相似文献   

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19.
Plantation and secondary forests form increasingly important components of the global forest cover, but our current knowledge about their potential contribution to biodiversity conservation is limited. We surveyed understory plant and carabid species assemblages at three distinct regions in temperate northeastern China, dominated by mature forest (Changbaishan Nature Reserve, sampled in 2011 and 2012), secondary forest (Dongling Mountain, sampled in 2011 and 2012), and forest plantation habitats (Bashang Plateau, sampled in 2006 and 2007), respectively. The α‐diversity of both taxonomic groups was highest in plantation forests of the Bashang Plateau. Beetle α‐diversity was lowest, but plant and beetle species turnover peaked in the secondary forests of Dongling Mountain, while habitats in the Changbaishan Nature Reserve showed the lowest turnover rates for both taxa. Changbaishan Nature Reserve harbored the highest proportion of forest specialists. Our results suggest that in temperate regions of northern China, the protected larch plantation forest established over extensive areas might play a considerable role in maintaining a high biodiversity in relation to understory herbaceous plant species and carabid assemblages, which can be seen as indicators of forest disturbance. The high proportion of phytophagous carabids and the rarity of forest specialists reflect the relatively homogenous, immature status of the forest ecosystems on the Bashang Plateau. China's last remaining large old‐growth forests like the ones on Changbaishan represent stable, mature ecosystems which require particular conservation attention.  相似文献   

20.
The sal (Shorea robusta) forest vegetation of Sohagibarawa Wildlife Sanctuary, Gorakhpur, India was analysed to assess plant diversity, regeneration pattern and the status of species conservation. A total of 208 plant species representing 165 genera and 72 families were recorded. Species richness, mean density and basal area of individuals in the observed forest were compared with those of other sal-dominated forests of India. The sal forest was rich in Papilionaceae (23 species), which contributed maximally to the total number of individuals of <30 cm girth. After sal, density was maximal for a leguminous shrub, Moghania chappar. In addition to the usual recruitment by seed, a number of species also showed non-seed regeneration through storage roots, sprouts or ramet proliferation. The individuals regenerating as sprouts from underground stem or storage organs contributed significantly to the sum total of individuals/ha. As much as 45.5% of the total individuals were of ramet origin and shared 10.6% of the total species richness of the forest. In stands facing moderate to low disturbance, thickets of dense entangled mass of vegetation, predominantly composed of thorny lianas, were identified that usually contained less common and rare species like Rauwolfia serpentina, Desmodium latifolium, Crotalaria alata and Gloriosa superba in addition to the frequent ones. These thickets help to conserve the special habitat conditions and provide protection for natural regeneration of several infrequent and rare plant species and thus contribute towards the maintenance and in situ conservation of overall diversity of recurrently disturbed forest vegetation.  相似文献   

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