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1.
Small-mammal communities were monitored over 4 years in South Moravian rural lowland forests in order to study relationships with various forest habitat types. Early successional sites (plantations) and forest edges maintained communities with higher abundance and diversity. Lowest total abundance was observed in unmanaged lowland forest and highest abundance in plantations with irregular undergrowth management. Low diversity was typical of non-fruiting monocultures. In plantations, both diversity and abundance were affected by herb layer removal, with sites subject to regular cutting, displaying lower levels. Significant differences in diversity and species richness were only detected between early and late successional sites, with the former showing higher values. Two basic small-mammal community groups were determined; (1) those inhabiting sites with a thick herb undergrowth and an open tree canopy (plantation) and (2) those inhabiting stands with sparse or no herb layer and a closed canopy (high forest). Forest stands support long-term populations of dominant small forest-dwelling mammal species and, as such, serve as reservoirs, even in rural landscapes dominated by intensive arable farming. Managed early succession lowland forests represent important refuges for a number of small open-habitat mammals negatively affected by intensive farming.  相似文献   

2.
Voles and shrews are key species in northern forest ecosystems. Thus, it is important to quantify to what extent new forestry practices such as planting of non-native tree species impact these small mammals. In northern Norway stands of coastal subarctic birch forests have increasingly been converted to non-native spruce stands during the last century. This leads to changes in the forest floor vegetation and soil conditions that can be expected to negatively impact the community of ground-dwelling small mammals. In this 10-year trapping study we contrasted seasonal small mammal population abundances in spruce plantations with four birch forest varieties. Six different small mammal species were trapped (in descending order of abundance; common shrew Sorex araneus, red vole Myodes rutilus, field vole Microtus agrestis, grey-sided vole M. rufocanus, pygmy shrew S. minutus and water shrew Neomys fodiens). None of the voles appeared to exhibit temporal dynamics resembling population cycles. The three most numerous species were clearly less abundant in the spruce plantations compared to the other forest types. Autumn abundances were most impacted by spruce plantations, indicating that growth rates in the reproductive season were more influenced than winter declines. Species associated with productive forest habitats (i.e. field vole and common shrew) were most impacted by tree species conversion. Still young spruce plantations inter-mixed with birch trees and the ecotone habitat, sustained small mammal abundances comparable to the native birch forests. This implies that managing spruce plantations to maintain a mix of different tree species and high spatial heterogeneity (i.e. more ecotones), will reduce the negative impacts on the small mammal community. On the contrary, if young spruce plantations, as they age become spruce monocultures covering larger parts of the landscapes than they do presently, the negative effects on small mammal communities may be larger than observed in the present study.  相似文献   

3.
Taking different forests in Aershan of Inner Mongolia as sample plots,diversity and dominant species of arthropods were studied.The results show that two classes,17 orders,68 families,130 species and 3742 individuals were identified and 92.31% of total species appeared in natural forests,and 75.38% of total species appeared in plantations.The orders of Lepidoptera,Coleop-tera,Diptera and Hymenoptera covered most of the collected arthropods.In different forest types,diversity indices is natural mixed forests...  相似文献   

4.
In conifer plantations, enhancement of species diversity has become an important management goal. Although thinning is a useful method to enhance diversity, determining optimum thinning intensities may be rather complicated because of potential trade-offs among a broad array of management goals (e.g., recovery of biodiversity, increasing individual tree sizes, increasing net primary production, saving management costs). To evaluate the optimum thinning intensity by analyzing these relationships, we conducted a thinning experiment with three different thinning intensities—unthinned, 33% thinned, and 67% thinned—in a Cryptomeria japonica plantation in 2003, and investigated the number, diameter at breast height (DBH), and diversity of hardwoods (height?>?1.5?m) in 2008, and the growth of conifers over five?years. In hardwoods, the number of individuals, number of species, mean DBH, and total basal area were greatest in the 67% thinned treatment, irrespective of successional status. However, Shannon’s diversity index did not differ among the three treatments due to a disproportionate increase with thinning intensity in the abundance of a mid-successional species, Cornus controversa. Diameter growth of conifers was also highest in the 67% thinned and lowest in the unthinned treatment, whereas the reverse was true for stand volume increment. These results suggest that intensive thinning is a reliable method to convert conifer plantations into conifer–hardwood mixed forests at canopy level much more quickly and consistently than weak thinning, although primary production is to some extent reduced. If forest managers prefer sustainable timber production of conifers rather than full recovery of diversity, weak thinning may be suitable.  相似文献   

5.
增城市主要森林群落植物多样性研究   总被引:11,自引:4,他引:11       下载免费PDF全文
报道了增城市主要林区次生常绿阔叶林、马尾松林、湿地松林、南洋楹林等4种森林群落的植物多样性。调查了19个400m^2的样方,共记录了163种乔灌木植物种类。除5种未能鉴定外,其余158种分属50科97属,包括2种国家保护植物:穗花杉和白桂木。等级聚类分析和无偏对应分析(DCA)结果显示:次生林群落多样性较高,人工林较低。多样性变化的总趋势为:次生林>南洋楹林>马尾松林>湿地松林。次生林与人工林群落在种类组成和多样性方面有较大的差异,次生林群落的树木种类较丰富,但大多数为早期的先锋树种,原生的地带性森林建群种,如壳斗科、樟科、木兰科等种类很少,而且相当多的次生林种类仅局限于天然林中,很少见于人工林中;人工林中常见的种类大都是那些具有鸟播种实的种类。  相似文献   

6.
The aim of this study was to evaluate the influence of forest structure (mainly resulting from human uses) and forest type (the identity of the dominant tree species) on biodiversity. We determined the diversity of two taxonomical groups: the understory vegetation and the edaphic carabid beetle fauna. We selected eight types of forest ecosystems (five replicates or stands per forest type): pine (Pinus sylvestris) plantations of three age classes (10, 40 and 80 years since reforestation), an old-growth relict natural pine forest, and four types of oak (Quercus pyrenaica) stands: mature forests with livestock grazing and firewood extraction, mature forests where uses have been abandoned, “dehesa” ecosystems and shrubby oak ecosystems. The results obtained by a global PCA analysis indicated that both tree size and dominant species influenced the ordination of the 40 forest stands. In general, carabids were more sensitive to changes in forest heterogeneity and responded more clearly to the analysed structural variables than the understory vegetation, although the species richness of both groups was significantly correlated and higher in case of oak forests. Pine forest ecosystems were characterised by the lowest species richness for both taxonomical groups, the lowest plant diversity and by the lowest coefficients of variation and, consequently, low structural heterogeneity. As a result, it was very difficult to discriminate the effects of the spatial heterogeneity and the dominant tree species on biodiversity.  相似文献   

7.
Mainly the following four species of voles (Arvicolidae) are harmful in forest plantations in Central Europe: the field vole (Microtus agrestis), the common vole (M. arvalis), the redbacked vole (Clethrionomys glareolus) and the water vole (Arvicola terrestris). Different possibilities of development of an integrated control programme are discussed. The most important factors are: identification and forecasting of damages, determination of control thresholds, optimized timing of control operation and selection of efficient control methods with minimized environmental hazards. Finally the system of surveillance of rodents in Bavarian forest plantations is described, whereby different preventive measures by means of forest cultivation play an important role. Furthermore new methods of forecast and of control such as bait station technique with new types of rodenticides and attractants are tested.  相似文献   

8.
Of the most common types of land use, agroecosystems put enormous pressure on many groups of biological organisms. Amphibians are not the exception and here we show the value of these habitats to the conservation of this group. We evaluated the diversity of amphibians in coffee plantations (traditional and specialized shade) and also in fragments of cloud forest, the ecosystem that was dominant in pre-agricultural central Veracruz, Mexico. A sampling effort of 2,688 person hours recorded 1,078 amphibians belonging to 26 species, 10 families and three orders. Based on the mean complementarity of 64 %, the non-metric multidimensional scaling analysis identified three groups of communities indicating a high degree of species turnover. The Craugastoridae family was dominant at the study sites, representing 40 % of the entire sample. Amphibian diversity was high in cloud forest fragments, followed by the traditional coffee plantation. However, amphibian richness in the specialized shaded coffee plantation was not significantly different from that of the other two habitats. We conclude that the different types of coffee agrosystems are reservoirs for at least 46 % of the species native to cloud forest, indicating that this habitat is very important to the conservation of the amphibian fauna in central Veracruz.  相似文献   

9.
Although Quercus liaotungensis forest is an important component of Loess Plateau forest ecosystems, little is known about the ectomycorrhizal fungal (EMF) symbiosis of Q. liaotungensis in this ecosystem. Here we investigated EMF communities of Q. liaotungensis along three successional stands on the central Loess Plateau (Yan’an, China): a seedling stand (1 to 3-year-old seedlings under a Populus davidiana forest stand), a young tree stand (20 to 30-year-old Q. liaotungensis forest stand), and a mature tree stand (50 to 70-year-old Q. liaotungensis forest stand). In each stand, the Q. liaotungensis roots were sampled, then EMF communities were examined on the basis of EMF morphotyping, PCR–RFLP, and DNA sequencing. In total, 70 EMF species were observed, and the total richness of estimated species exceeded 100 EMF species. The EMF community was composed of a few common taxa (approx. 7 %) and many rare taxa (approx. 61 %). EMF richness in young and mature trees was higher than in seedlings. EMF communities of young and mature trees were more similar than those of seedlings and trees. Nonmetric multidimensional scaling ordinations of the EMF community revealed more separation among Q. liaotungensis of different age. This study provides preliminary insight into the taxonomic diversity of EMF of Q. liaotungensis along different successional stands on the Loess Plateau.  相似文献   

10.
Much research effort is being devoted to developing forest management practices with limited impacts on biodiversity. While the impact of poplar Populus sp. plantations on biodiversity is relatively well-known at the landscape scale, the impact of alternative management practices at the plantation scale has received much less attention. Yet biodiversity is likely to be impacted by the choice of the poplar clone, stem density at plantation, type and duration of the understory control, and age at which the poplars are harvested. In this study, we investigated the impact of these factors on herbaceous plant communities with data from plant surveys conducted in 85 young (2–5 years) and 96 mature (11–17 years) hybrid poplar high-forest plantations in northern France. On average, ruderal or generalist plants contributed to 40.5% of the plot species richness; tall herbs (60.2%), forest (26%) and meadow plants (13.8%) contributed to the remaining 59.5% more specialised species. Soil moisture and soil nitrogen were major determinants of plant communities: wet soils were favourable to tall herbs, while meadow and forest species preferred moist soils; a significantly lower diversity of the three species groups was reported in the nutrient richer soils (in mature plantations only for forest plants). Mean species richness decreased with plantation age except for forest species. Plant communities in young plantations showed little differences in composition according to the type of understory control (chemical, mechanical or both). The development of a shrubby layer in mature plantations was restricted to the drier soils and was detrimental to both meadow plants and tall herb species. Effects of previous land use on forest and tall herb species were found only in young plantations, suggesting a rapid reset of plant communities for these two groups. This may not be the case for meadow species as the influence of previous land use was significant in mature plantations only. Finally, clone type and stem density at plantation had no significant impact on plant communities. Adjusting age at which the poplars are harvested seems the only effective way to drive plant communities in high-forest poplar plantations: delaying poplar harvest (probably beyond 15–20 years) would benefit forest plants, while advancing poplar harvest (about 10 years) would benefit tall herbs, especially in wet soil conditions.  相似文献   

11.
This study assessed the ethnobotanical use and knowledge of forest plant diversity among the Ribeirinhos, a traditional population of the Brazilian Amazon living in a protected area (Tapajós National Forest, West of Pará), and compared the importance of forest plants used in their daily activities with the use of cultivated plants (agrobiodiversity) from their home gardens and swidden-fallows. We used two complementary quantitative ethnobotanical methods, based on (i) daily scan observations in 14 families’ homes, and (ii) ethnobotanical inventories of trees, palms and lianas of DBH ≥ 5 cm in 23 plots each of 0.1-ha, set up in three types of forests. Analyses of the ethnobotanical surveys in the plots showed that most forest species (120 out of the 140 inventoried, i.e. 86 %) were acknowledged to be useful by the informants (use value >0) and accounted for 91.2 % of the inventoried individuals measuring DBH ≥ 5 cm. However, daily observations of plant gathering in homes showed that only a few forest species considered ‘useful’ were used daily, whilst species cultivated in gardens and swidden-fallows represented the majority of species used. The Ribeirinhos were also found to know as much about using forest plant diversity, if not more, than other traditional groups from Amazonia or from other tropical regions of South America, including the Amerindians. The article concludes with some recommendations for adapting development practices to local uses of plant diversity in this protected area.  相似文献   

12.
Understory herb communities in the Southern Appalachians are among the highest biodiversity plant communities in North America. In the mid-1990s, a debate began over whether understory herb communities recover to their pre-disturbance states following logging. Studies showing reduced herb-layer diversity in previously logged forests were criticized for not accounting for intersite environmental heterogeneity. More recent studies have addressed environmental heterogeneity, but have neglected long-term recovery by using “mature forests” as young as 80 years old as the benchmark for diversity comparison, even though old growth stands have disturbance return intervals exceeding 500 years. Here we address concerns clouding previous studies of high-diversity Appalachian herb communities and investigate their long-term recovery by comparing paired sites of old growth forest and forest logged 100–150 years ago. We found that species richness and individual abundance is greater in old growth forests than mature forests and that species composition differed significantly between the two. Turnover in species among old growth and mature forests accounted for 11% of the total species richness and was significantly greater than expected. Species turnover at intermediate (5–50 m) and landscape-scales (>10 km) contributed the most towards total species richness. Herb communities in rich cove forests have successional trajectories that exceed 150 years, with important community changes still occurring long after the forest returns to what has been previously termed a “mature” state. To conserve the diverse herb layer, we conclude that mature forest stands are too young to serve as baselines for recovery, landscape-scale preservation of multiple forest stands is needed to maximize species richness, and maintaining 100–150-year logging rotations will likely lead to loss of biodiversity.  相似文献   

13.
In spite of its high diversity the forests in Southern Ecuador are highly endangered by deforestation. One of the main reasons for the loss of forests is the conversion into pastures. Due to their fast degradation, the pastures are abandoned after several years and form an increasing area of unproductive land. The remoteness from existing forest edges is discussed as one reason for the very slow natural reforestation of these areas. In this study we analyzed the regeneration of a secondary forest after approx. 38 years of succession in relation to the distance from the surrounding forest. We revealed that regeneration was rather slow. Especially larger trees with dbh > 10 cm were very scarce. Only Dioicodendron dioicum, Graffenrieda emarginata and Clusia sp. achieved larger diameters. The basal area of the secondary forest is still far beyond the original level in the primary forest. The number of species on plot level and the Shannon index were significantly lower in the secondary forest compared to the primary forest. The total number of species decreased from 47 to 31 with increasing distance from the forest edge and the similarity of species composition to the upper story declined to a level of 56.4 (Sörensen). Alzatea verticillata, Macrocarpea revoluta and Palicourea andaluciana had significantly higher abundances in the succession stages than in the natural forest. The most abundant species in all regeneration plots, G. emarginata and Purdiea nutans, seem to be generalists as they did not show preference either to natural forest or successional stages.  相似文献   

14.
Natural forests have been increasingly replaced by artificial plantations around the world. Some research results suggest that artificial plantations can promote natural regeneration. The efforts in establishing protective forests in Hong Kong over the last 50 years after the Second World War have resulted in many exotic tree plantations which are ideal sites for the study of natural regeneration. This study looked at the seed rain and understorey woody plant diversity in three Lophostemon confertus plantations (25–40 years old) in Hong Kong. All the plantations were > 1 km from the nearest seed sources. Two of the plantations had a seed rain comparable in density and diversity to unplanted grasslands, and the understorey plant diversity was also low and dominated by shrubs. The other site had a higher and more diverse seed rain, as well as higher understorey stem density, but both the seed rain and the understorey were dominated by the shrub Psychotria asiatica. The poor seed rain at two sites and the rarity of potential canopy tree species in both the seed rain and understory regeneration at all sites suggest that planting exotic monocultures does not promote succession. Enrichment planting will be needed to restore forest diversity.  相似文献   

15.
The Serra do Brigadeiro State Park (PESB) is one of the largest fragments of Brazilian Atlantic Rainforest, and it is relevant for native species conservation. However, monocultures settled around the Park resulted in extensive open areas that facilitate the establishment of alien species on the PESB perimeter, which may threaten native species conservation therein, since biological invasion is the second main cause of global biodiversity loss. In this region, there are also farmers planting agroforestry systems (AFS), characterized by tree-based intercropping, which are structurally more similar to the Atlantic Rainforest reminiscent fragments present in the region and may limit local occurrence of potentially invasive exotic weeds for several reasons, such as the high levels of shade provided by trees, the groundcover that result from loss of tree leaves and the increased competition for belowground resources. This study aimed to test whether AFS limit exotic species establishment when compared to monoculture systems. Accordingly, three coffee monocultures and three agroforestry coffee plantations around the PESB were studied. In each of the six study areas, 30 plots of 1 m2 were established between the lines of coffee plantation, where all species present were surveyed. In both treatments, rarefaction curves were constructed to evaluate native and exotic richness, and diversity of these two categories was estimated through Simpson index inverse (1/D). All 13 sampled exotic species were present in monocultures, but only three of them occurred in AFS. Besides, alien diversity in monocultures (\(1/D\) = 2.173 ± 0.011) was significantly higher than in AFS (\(1/D\) = 1.031 ± 0.001). Such changes in alien plant community between land-use show that AFSs limit invasive species establishment. Therefore, when planted around protected areas, AFS may contribute to the control of biological invasions and to biodiversity conservation.  相似文献   

16.
Plantation forests comprise an important part of the forested areas in European countries. Intensive forestry management and short-rotation cycles of plantation forests reduce habitat diversity and change the composition of invertebrate assemblages, mainly by reducing the number of habitat specialist species. Here, we analysed the effect of vegetation structure, amount of dead organic matter (DOM) and plantation age on spider functional diversity and assemblage structure in short-rotation plantations of native silver poplar in Hungary. Three stages, representing young plantations, 6- to 10-year-old stands (five stands), middle-aged plantations, aged between 23 and 26 years (five stands) and mature, 35- to 37-year-old forests at commercial maturity (five stands) were sampled. Each sample consisted of the data of ten pitfall traps. Traps were installed 5 m from each other in a 2 × 5 grid. Functional diversity was positively related to vegetation structure. High functional diversity indicates a higher number of available niches and potential resources. The abundance of moist habitat species and forest specialist species was positively correlated with DOM. Furthermore, moist habitat species were also related to vegetation structure. The most important environmental parameters affecting spiders were factors attributed to trees (litter and DOM), understory vegetation structure and, to a lesser extent, forest age. Different-aged stands may be similar in terms of species composition of their spider fauna if they comprise the same habitat structural patterns. Our study emphasises that the simple habitat structure of plantation forests has a negative effect on spider communities.  相似文献   

17.
Replantation of degraded forest using rapidgrowth trees can play a significant role in global carbon budget by storing large quantities of carbon in live biomass,forest floor,and soil organic matter.We assessed the potential of 20-year old stands of three rapid-growth tree species,including Alnus subcordata,Populus deltoides and Taxodium distichum,for carbon(C) storage at ecosystem level.In September 2013,48 replicate plots(16 m × 16 m) in 8 stands of three plantations were established.36 trees were felled down and fresh biomass of different components was weighed in the field.Biomass equations were fitted using data based on the 36 felled trees.The biomass of understory vegetation and litter were measured by harvesting all the components.The C fraction of understory,litter,and soil were measured.The ecosystem C storage was as follows: A.subcordata(626.5 Mg ha~(-1)) [ P.deltoides(542.9Mg ha~(-1)) [ T.distichum(486.8 Mg ha~(-1))(P \ 0.001),of which78.1–87.4% was in the soil.P.deltoides plantation reached the highest tree biomass(206.6 Mg ha~(-1)),followed by A.subcordata(134.5 Mg ha~(-1)) and T.distichum(123.3 Mg ha~(-1)).The highest soil C was stored in theplantation of A.subcordata(555.5 Mg ha~(-1)).The C storage and sequestration of the plantations after 20 years were considerable(25–30 Mg ha~(-1) year~(-1)) and broadleaves species had higher potential.Native species had a higher soil C storage while the potential of introduced species for live biomass production was higher.  相似文献   

18.
Arbuscular mycorrhiza fungi(AMF) are vital in the regeneration of vegetation in disturbed ecosystems due to their numerous ecological advantages and therefore are good indicators of soil and ecosystem health at large. This study was aimed at determining how the seasonal, vegetation cover density, edaphic and anthropogenic factors affect AMF root colonization(RC) and spore density(SD)in Desa'a dry Afromontane forest. AMF RC and SD in the rhizosphere of five dominant woody species, Juniperus procera, Olea europaea, Maytenus arbutifolia, Carissa spinarum and Dodonaea angustifolia growing in Desa'a forest were studied during the rainy and the dry seasons in three permanent study vegetation cover density plots(dense, medium, and poor). Each plot(160 x40 m~2) has two management practices(fenced and unfenced plots) of area. A 100 g sample of rhizosphere soil from moisturefree composite soil was used to determine spore density.Spore density ranged from 50 to 4467 spores/100 g soil,and all species were colonized by AMF within a range of 4–95%. Glomus was the dominant genus in the rhizosphere of all species. Vegetation cover density strongly affected SD and RC. The SD was significantly higher(p 0.05) in the poor vegetation cover density than in the other two and lowest in the dense cover; root colonization showed the reverse trend. Management practices significantly(p 0.05) influenced AMF SD and RC, with the fenced plots being more favoured. Seasons significantly(p 0.05) affected RC and SD. More RC and SD were observed in the wet period than the dry period. Correlating AMF SD and RC with soil physical and chemical properties showed no significant difference(p 0.05) except for total nitrogen. Disturbance, vegetation cover density, season and total nitrogen are significant factors that control the dynamics and management interventions to maintain the forest health of dry Afromontane forests.  相似文献   

19.
Drought and heat-induced forest dieback and mortality are emerging global concerns. Although Mediterranean-type forest (MTF) ecosystems are considered to be resilient to drought and other disturbances, we observed a sudden and unprecedented forest collapse in a MTF in Western Australia corresponding with record dry and heat conditions in 2010/2011. An aerial survey and subsequent field investigation were undertaken to examine: the incidence and severity of canopy dieback and stem mortality, associations between canopy health and stand-related factors as well as tree species response. Canopy mortality was found to be concentrated in distinct patches, representing 1.5 % of the aerial sample (1,350 ha). Within these patches, 74 % of all measured stems (>1 cm DBHOB) had dying or recently killed crowns, leading to 26 % stem mortality six months following the collapse. Patches of canopy collapse were more densely stocked with the dominant species, Eucalyptus marginata, and lacked the prominent midstorey species Banksia grandis, compared to the surrounding forest. A differential response to the disturbance was observed among co-occurring tree species, which suggests contrasting strategies for coping with extreme water stress. These results suggest that MTFs, once thought to be resilient to climate change, are susceptible to sudden and severe forest collapse when key thresholds have been reached.  相似文献   

20.
Secondary evergreen broadleaved forests are precious remnants for biodiversity conservation and templates for sustainable management of natural forests in subtropical China. Floristic composition, size structure, and spatial pattern of dominant tree species have been investigated for a subtropical secondary evergreen broadleaved forest in the Huitong Yingzuijie National Forest Reserve, Hunan, China. The location of all trees greater than 4 cm in diameter at breast height (DBH) were mapped within a 0.96-ha plot in which species, DBH, and total tree height were recorded. Ripley’s K(t) function was used to analyze spatial patterns and associations. The secondary forest consisted of 74 tree species and 1,596 stems per hectare. A reverse-J shaped DBH classes distribution was observed for all stems and trees of later seral species whereas trees of earlier successional species were distributed irregularly. Significant aggregated spatial patterns were observed for all trees within the forest and for conspecific trees of each dominant species. This result, and a repulsive spatial pattern for interspecific trees of Choerospondias axillaries and Cyclobalanopsis glauca against other dominant tree species, support segregation hypothesis. Contributions of seed dispersal, topographic heterogeneity, and competition to spatial patterns of conspecific trees vary depending on tree species. Attractive spatial pattern among interspecific trees of Liquidambar fortunei, Liquidambar formosana, and Pinus massoniana reflects stochastic colonization of pioneer tree species and a facilitation relationship. Although deciduous species are long-lived and persist over long successional processes, they will eventually be replaced by late seral evergreen species within the secondary forest if no disturbance events occur.  相似文献   

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