共查询到20条相似文献,搜索用时 31 毫秒
1.
We reviewed recent studies on the restoration of semi-natural forests after clearcutting of conifer plantations with specific
reference to the importance of setting restoration goals, general and specific factors influencing restoration, and the prediction
and judgment of successful restoration. For the restoration of semi-natural forests following the clearcutting of conifer
plantations, recovery levels and appropriate restoration methods cannot be considered separately from the aims of restoration
to provide ecosystem services. Restoration needs to be based on the setting of goals that correspond to the type and degree
of ecosystem services targeted. When we aim to restore vegetation dominated by late-seral canopy trees within as short a period
after the clearcutting of conifer plantations as possible, advanced regeneration in the pre-logged plantation is the most
important and reliable source of post-logging regeneration, just as it is in the recovery of disturbed non-plantation forests.
Advanced regeneration is not always present in plantations. Seedling establishment by seed rain from adjacent natural forest
patches after a disturbance can contribute to late-seral or canopy species; however, the range of the edge effect is generally
short, and the degree of the edge effect depends on the natural forest type and is more pronounced in deciduous forests, such
as those in cool-temperate climates, or in forests with a complex forest structure. Thus, advanced regeneration is a better
predictor of short-term forest recovery than measures based on seed rain from adjacent seed sources. However, restoration
achieved only through advanced regeneration can simplify the species composition, and the recolonization processes of gradual
species accession from seeds should be considered in the long-term context of restoration. 相似文献
2.
Recovery of late-seral vascular plants in a chronosequence of post-clearcut forest stands in coastal Nova Scotia,Canada 总被引:1,自引:1,他引:0
We investigated the impacts of clearcutting on the ground vegetation of remnant late-successional coastal Acadian forests in southwestern Nova Scotia. Vegetation was sampled in 750 1-m2 quadrats established in 16 stands belonging to different recovery periods since clearcutting (3–54 years) and 9 late-successional forests (100–165 years) with no signs of significant human disturbance. Our objectives were to: i) describe the changes in species richness, diversity, and abundance of ground vegetation after clearcutting; ii) examine the responses of residual species (i.e., late-successional flora) to clearcutting; and iii) determine whether any forest species were restricted to or dependent upon the late-successional stages of stand development for maximal frequency and/or abundance. Although clearcutting had no immediate impact on overall alpha richness or diversity, the richness and diversity of residual plants declined after canopy removal and showed no evidence of recovery over 54 years of secondary succession. Consequently, compositional differences between secondary and late-seral stands persisted for many decades after clearcutting. Several understory herbs (e.g., Coptis trifolia (L.) , Oxalis montana (L.), Monotropa uniflora (L.)) were restricted to or attained their highest frequency and abundance in late-seral forests. These results suggest that the preservation of remnant old stands may be necessary for the maintenance of some residual plants in highly disturbed and fragmented forest landscapes in eastern Canada. 相似文献
3.
To contribute to a better understanding of the regeneration strategy of Betula albosinensis forests and the likely reasons behind either the successful recovery or failure after strip clearcutting, we compared the population structures and spatial patterns of B. albosinensis in eight B. albosinensis stands in Qinling Mountains, China. Four cut and four uncut stands were selected, and each sampled using a single large plot (0.25 ha). Results indicated that, on the one hand, B. albosinensis recruitment was scarce (average of 48 stems ha−1) in the uncut stands, relative to the mature population (average of 259 stems ha−1), suggesting a failure of recruitment. On the other hand, the subsequent regeneration approximately 50 years after the strip clearcutting showed that the density of the target species seedlings and saplings has increased significantly, and the current average density of seedlings and saplings was 156 stems ha−1. The clumped spatial pattern of B. albosinensis suggested that their regeneration was highly dependent on canopy disturbance. However, recruitment remained poor in the uncut stands because most gaps were small in scale. The successful regeneration of sunlight-loving B. albosinensis after strip clearcutting was attributed to the exposed land and availability of more sunlight. Bamboo density did not influence B. albosinensis recruitment in the uncut stands. However, stand regeneration was impeded after strip clearcutting; thus, removing bamboo is essential in improving the competitive status of B. albosinensis at the later stage of forest regeneration after clearcutting. The moderate severity of disturbance resulting from strip clearcutting reversed the degeneration trend of primary B. albosinensis stands. This outcome can help strike a balance between forest conservation and the demand for wood products by releasing space and exposing the forested land for recruitment. Life history traits and spatiotemporal disturbance magnitude are important factors to consider in implementing effective B. albosinensis regeneration strategies. 相似文献
4.
Motohiro Hasegawa Kimiko Okabe Kenji Fukuyama Shun’ichi Makino Isamu Okochi Hiroshi Tanaka Hideaki Goto Takeo Mizoguchi Tadashi Sakata 《Experimental & applied acarology》2013,59(4):391-408
The community structures of Mesostigmata, Prostigmata, and Oribatida in the soil of broad-leaved regeneration forests and conifer plantations of various ages were assessed alongside soil and plant environmental variables using three response metrics (density, species richness, and species–abundance distribution). The density and species richness of mites recovered swiftly after clear-cutting or replanting. Oribatid mites dominated the soil mite communities in terms of densities and species richness for both forest types. Soil mite communities in broad-leaved forests was related to forest age, the crown tree communities index, and forest-floor litter weight. In contrast, soil mite communities in the conifer plantation sites were related to various indices of understory plants. The development of the understory plants was synchronized with the silvicultural schedules, including a closed canopy and thinning. Such a conifer plantation management may affect indirectly the community of mites. 相似文献
5.
Knowledge of the recovery of insect communities after forest disturbance in tropical Africa is very limited. Here, fruit‐feeding butterflies in a tropical rain forest at Kibale National Park, Uganda, were used as a model system to uncover how, and how fast, insect communities recover after forest disturbance. We trapped butterflies monthly along a successional gradient for one year. Traps were placed in intact primary forest compartments, heavily logged forest compartments with and without arboricide treatment approximately 43 years ago, and in conifer‐clearcut compartments, ranging from 9 to 19 years of age. The species richness, total abundance, diversity, dominance, and similarity of the community composition of butterflies in the eight compartments were compared with uni‐ and multivariate statistics. A total of 16,728 individuals representing 88 species were trapped during the study. Butterfly species richness, abundance, and diversity did not show an increasing trend along the successional gradient but species richness and abundance peaked at intermediate stages. There was monthly variation in species richness, abundance, diversity and composition. Butterfly community structure differed significantly among the eight successional stages and only a marginal directional change along the successional gradient emerged. The greatest number of indicator species and intact forest interior specialists were found in one of the primary forests. Our results show that forest disturbance has a long‐term impact on the recovery of butterfly species composition, emphasizing the value of intact primary forests for butterfly conservation. 相似文献
6.
Large areas of rainforests in Australia and other tropical regions have been extensively cleared since the mid‐19th century. As abandoned agro‐pastoral land becomes increasingly prominent, there is an ongoing need to identify cost‐effective approaches to reinstate forest on these landscapes. Assisted regeneration is a potentially lower cost restoration approach which aims to accelerate forest recovery by removing barriers to natural regeneration. However, despite being widely used its ecological benefits are poorly quantified, particularly on long cleared and grazed land. This study quantified the benefits of assisted regeneration on previously cleared land in a subtropical rainforest ecosystem within eastern Australia. Three different site types were used (grazed, grazing excluded and grazing excluded plus assisted regeneration, each with a maximum distance of 120 m to remnant forest) to compare forest recovery up to 10 years after grazing was relieved with and without 4–6 years of assisted regeneration. Assisted regeneration sites showed a threefold increase in canopy cover, fourfold increase in native tree and shrub species richness and over 40 times greater native stem density compared to nonassisted regeneration sites. Stimulation of native recruitment appears dependent on the simultaneous removal of multiple barriers to regeneration, with the exclusion of grazing alone insufficient. This demonstrates the additional ecological benefits arising from investment in assisted regeneration. It offers considerable promise as a cost‐effective tool for accelerating and improving reinstatement of forest on retired agro‐pastoral land in the humid subtropics. 相似文献
7.
Mejía-Domínguez NR Meave JA Díaz-Ávalos C 《International journal of biometeorology》2012,56(2):305-318
Analyzing the relationship between the spatial structures of environmental variables and of the associated seedling and sapling
communities is crucial to understanding the regeneration processes in forest communities. The degree of spatial structuring
(i.e., spatial autocorrelation) of environmental and sapling community variables in the cloud forest of Teipan, S Mexico,
were analyzed at a 1-ha scale using geostatistical analysis; after fitting semivariogram models for each set of variables,
the association between the two sets was examined through cross-variograms. Kriging maps of the sapling community variables
(density, cover, species richness, and mortality and recruitment rates) were obtained through conditional simulation method.
Canopy openness, total solar radiation, litter depth, soil temperature and soil moisture were spatially structured, as were
sapling density, species richness and sapling mortality rate. Mean range in semivariograms for environmental and sapling community
variables were 13.14 ± 3.67 and 12.68 ± 5.71 m (±SE), respectively. The spatial structure of litter depth was negatively associated
with the spatial structures of sapling density, species richness, and sapling community cover; in turn, the spatial structure
of soil moisture was positively associated with the spatial structure of recruitment rate. These associations of the spatial
structures of abiotic and sapling community variables suggest that the regeneration processes in this cloud forest is driven
by the existence of different microsites, largely characterized by litter depth variations, across which saplings of tree
species encounter a range of opportunities for successful establishment and survival. 相似文献
8.
Sini Savilaakso Jenny Koivisto Timo O. Veteli Jyrki Pusenius Heikki Roininen 《Biodiversity and Conservation》2009,18(14):3931-3948
Many of the protected forest areas in Uganda have been subject to logging in the past. It is known that logging changes communities,
but how long these changes last is unclear. Most of the studies on butterflies and moths have looked at the effects of logging
relatively shortly (<15 years) after the logging took place. In this study we investigated community of herbivorous lepidopteran
larvae and its temporal dynamics in a natural forest and three differently managed forest compartments after 40 years of regeneration.
We collected samples of larvae from the leaves of Neoboutonia macrocalyx Pax. between April 2006 and March 2008 in Kibale National Park, Western Uganda. Herbivory, density of larvae, and species
richness were significantly lower in logged compartments than in natural forest. Furthermore, the community composition differed
significantly between the logged compartments and the natural forest. There was seasonal variation in larval density, species
richness and diversity. In species richness and diversity the variation was synchronous in all the study areas, but larval
density did not vary synchronously across the compartments, probably due to the impact of logging on the environment. We also
observed changes in the community composition during different seasons in all the study areas. We attribute the long term
impact of logging to the hindered regeneration of logged compartments and recommend restoration activities to help to return
the logged areas closer to the natural state. 相似文献
9.
Gabriel Gutiérrez-Granados Diego R. Pérez-Salicrup Rodolfo Dirzo 《Biodiversity and Conservation》2011,20(7):1571-1585
In this paper we tested the hypothesis that logging effects in the adult tree community reverberate upon the regeneration
contingent. We examined the differences on the tree community between forest reserves and 10 year-old logged areas in the
Yucatan Peninsula. We used a paired design in three independent sites to estimate the effects of logging on tree species richness,
diversity, composition and structure. Analyses were conducted differentiating individuals of four diameter-size classes: 1–5,
5–10, 10–25, and >25 cm DBH. We found out that there were differential effects by size. Species richness in the smaller and
larger diameter-size classes was significantly lower in logged areas. Floristic composition was also different between logged
and unlogged areas, with a trend towards more secondary forest associated species and less primary forest associated species
in logged areas, and a higher density of species represented by a single individual in unlogged reserves. In terms of structure,
trees DBH <10 cm, lianas, and re-sprouting stumps were more abundant in logged areas. Our findings suggest that 10 years after
logging, harvested areas show alterations in structure, and potentially a reduction in species richness. We suggest that to
make timber extraction and forest conservation compatible at this site, it is necessary to gain a better understanding of
the ecology and regeneration requirements of the less abundant species, and to assess whether current logging practices might
hinder their permanence in the study area. 相似文献
10.
Micaela Medina Magali Prez Flores Juan Francisco Goya Paula Ines Campanello Martin Alcides Pinazo Luis Javier Ritter Marcelo Fabian Arturi 《Austral ecology》2020,45(2):229-239
Deforestation is a global process that has strongly affected the Atlantic Forest in South America, which has been recognised as a threatened biodiversity hotspot. An important proportion of deforested areas were converted to forest plantations. Araucaria angustifolia is a native tree to the Atlantic Forest, which has been largely exploited for wood production and is currently cultivated in commercial plantations. An important question is to what extent such native tree plantations can be managed to reduce biodiversity loss in a highly diverse and vulnerable forest region . We evaluated the effect of stand age, stand basal area, as a measure of stand density, and time since last logging on the density and richness of native tree regeneration in planted araucaria stands that were successively logged over 60 years, as well as the differences between successional groups in the response of plant density to stand variables. We also compared native tree species richness in planted araucaria stands to neighbouring native forest. Species richness was 71 in the planted stands (27 ha sampled) and 82 in native forest (18 ha sampled) which approximate the range of variation in species richness found in the native forests of the study area. The total abundance and species richness of native trees increased with stand age and time since last logging, but ecological groups differed in their response to such variables. Early secondary trees increased in abundance with stand age 3–8 times faster than climax or late secondary trees. Thus, the change in species composition is expected to continue for a long term. The difference in species richness between native forest and planted stands might be mainly explained by the difference in plant density. Therefore, species richness in plantations can contribute to local native tree diversity if practices that increase native tree density are implemented. 相似文献
11.
Secondary forests that develop following land abandonment could compensate for the losses of diversity and structure that accompany deforestation of old‐growth forests in tropical regions. Whether secondary forests can harbor similar species richness, density, and composition of old‐growth forests for vascular epiphytes remains largely unknown for secondary forests older than 50 yr. We examined community structure (species richness, density, and species composition) of vascular epiphytes in older secondary forests between 35 and 115 yr after land abandonment and nearby old‐growth forests to determine if the community structure of epiphytes in secondary forests approaches that of old‐growth forests over time. The recovery of epiphyte species richness was rapid with 55‐year‐old forests containing 65 percent of old‐growth epiphyte species richness. Secondary forest epiphyte communities were found to be statistically nested within secondary forests older in age and within old‐growth forests. Similarity of epiphyte communities to old‐growth forests increased to 75 percent, 115 yr after abandonment. This study suggests that secondary forests will likely recover old‐growth epiphyte richness and composition given enough time. Epiphyte densities did not recover quickly with 55‐year‐old forests having 14 percent and 115‐year‐old forests having only 49 percent of the density of old‐growth forest epiphytes. The low density of epiphytes in secondary forests could impact rainforest diversity and function. We conclude that in less than 115 yr, although secondary moist forests have high conservation value for some aspects of community structure, they are unlikely to compensate biologically for the loss of diversity and ecosystem function that high epiphyte densities provide. 相似文献
12.
Martha Sample Clare E. Aslan Nahuel Policelli Robert L. Sanford Erik Nielsen Martín A. Nuez 《Austral ecology》2019,44(8):1384-1397
Nonnative conifers are widespread in the southern hemisphere, where their use as plantation species has led to adverse ecosystem impacts sometimes intensified by invasion. Mechanical removal is a common strategy used to reduce or eliminate the negative impacts of nonnative conifers, and encourage native regeneration. However, a variety of factors may preclude active ecological restoration following removal. As a result, passive restoration – unassisted natural vegetation regeneration – is common following conifer removal. We asked, ‘what is the response of understorey cover to removal of nonnative conifer stands followed by passive restoration?' We sampled understorey cover in three site types: two‐ to ten‐year‐old clearcuts, native forest and current plantations. We then grouped understorey species by origin (native/nonnative) and growth form, and compared proportion and per cent cover of these groups as well as of bare ground and litter between the three site types. For clearcuts, we also analysed the effect of time since clearcut on the studied variables. We found that clearcuts had a significantly higher average proportion of nonnative understorey vegetation cover than native forest sites, where nonnative vegetation was nearly absent. The understorey of clearcut sites also averaged more overall vegetation cover and more nonnative vegetation cover (in particular nonnative shrubs and herbaceous species) than either plantation or native forest sites. Notably, 99% of nonnative shrub cover in clearcuts was the invasive nonnative species Scotch broom (Cytisus scoparius). After ten years of passive recovery since clearcutting, the proportion of understorey vegetation cover that is native has not increased and remains far below the proportion observed in native forest sites. Reduced natural regeneration capacity of the native ecosystem, presence of invasive species in the surrounding landscape and land‐use legacies from plantation forestry may inhibit native vegetation recovery and benefit opportunistic invasives, limiting the effectiveness of passive restoration in this context. Abstract in Spanish is available with online material. 相似文献
13.
Nicholas J. Berry Oliver L. Phillips Simon L. Lewis Jane K. Hill David P. Edwards Noel B. Tawatao Norhayati Ahmad David Magintan Chey V. Khen M. Maryati Robert C. Ong Keith C. Hamer 《Biodiversity and Conservation》2010,19(4):985-997
The carbon storage and conservation value of old-growth tropical forests is clear, but the value of logged forest is less certain. Here we analyse >100,000 observations of individuals from 11 taxonomic groups and >2,500 species, covering up to 19?years of post-logging regeneration, and quantify the impacts of logging on carbon storage and biodiversity within lowland dipterocarp forests of Sabah, Borneo. We estimate that forests lost ca. 53% of above-ground biomass as a result of logging but despite this high level of degradation, logged forest retained considerable conservation value: floral species richness was higher in logged forest than in primary forest and whilst faunal species richness was typically lower in logged forest, in most cases the difference between habitats was no greater than ca. 10%. Moreover, in most studies >90% of species recorded in primary forest were also present in logged forest, including species of conservation concern. During recovery, logged forest accumulated carbon at five times the rate of natural forest (1.4 and 0.28?Mg?C?ha?1?year?1, respectively). We conclude that allowing the continued regeneration of extensive areas of Borneo??s forest that have already been logged, and are at risk of conversion to other land uses, would provide a significant carbon store that is likely to increase over time. Protecting intact forest is critical for biodiversity conservation and climate change mitigation, but the contribution of logged forest to these twin goals should not be overlooked. 相似文献
14.
We examined long‐term responses of an Amazonian bird assemblage to wildfire disturbance, investigating how understory birds reacted to forest regeneration 1, 3, and 10 years after a widespread fire event. The bird community was sampled along the Arapiuns and Maró river catchments in central Brazilian Amazonia. Sampling took place in 1998, 2000, and 2008 using mist‐nets in eight plots (four burned, four unburned sites). Species richness did not change significantly in unburned sites. In burned sites, however, we found significantly lower richness in 1998, higher richness in 2000, and similar richness in 2008. Multi‐dimensional scaling ordination showed consistent differences in bird communities both within burned sites sampled in different sampling years, and between burned and unburned sites in all years. Of the 30 most abundant species, 12 had not recovered 10 years after the fires, including habitat specialists such as mixed flocks specialists and ant‐followers. Fire‐disturbance favored three species (two hummingbirds and a manakin) in the short term only. All other species were either favored throughout the study (seven species of omnivores and small insectivores) or did not show a clear response (eight species). In burned sites, we also found significantly lower abundance of species sensitive to disturbances and habitat specialists over the entire study period. Although the bird community seems to be recovering in terms of richness, the overall community composition and abundance of some species in post‐burned and unburned sites remain very different, and have not recovered after 10 years of forest regeneration. 相似文献
15.
Intermediary disturbance increases tree diversity in riverine forest of southern Brazil 总被引:1,自引:0,他引:1
Jean Carlos Budke João André Jarenkow Ary Teixeira de Oliveira-Filho 《Biodiversity and Conservation》2010,19(8):2371-2387
Floods are frequently associated with disturbance in structuring riverine forests and they lead to environmental heterogeneity
over space and time. We evaluated the distribution of tree species, ecological groups, species richness and diversity from
the point bar to the slope of a riverside forest in southern Brazil (Lat. 30°01′S, Long. 52°47′W) to analyze the effects of
flooding on soil properties and forest structure. A plot of 50 × 200 m divided in five contiguous transects of 10 × 200 m
parallel to the river was installed, where we measured all the individual trees with pbh ≥ 15 cm. A detailed topographical
and soil survey was carried out across the plot and indicated significant differences in organic matter and most mineral nutrients
through the topographical gradient. The 1,229 surveyed individuals belonged to 72 species and 35 families. We used Partial
CCA and Species Indicator Analysis to observe the spatial distribution of species. Both analyses showed that species distribution
was strongly related to the flooding gradient, soil properties and also by space and pure spatial structuring of species and
environmental variables (spatial autocorrelation), although a large part of variation remains unexplained. The ecological
groups of forest stratification, plant dispersal and requirements for germination indicated slight differences among frequently,
occasional and non-flooded transects. Species richness and diversity were higher at intermediate elevations and were associated
to the increased spatial–temporal environmental heterogeneity. Across the plot, the direct influence of flooding on tree species
distribution created a vegetation zonation that is determined by predicted ecological traits. 相似文献
16.
Question: Reliable estimates of understorey (non-tree) plant cover following fire are essential to assess early forest community recovery. Photographic digital image analysis (DIA) is frequently used in seral, single-strata vegetation, given its greater objectivity and repeatability compared to observer visual estimation; however, its efficacy in multi-strata forest vegetation may be compromised, where various visual obstructions (coarse downed wood [CDW], conifer regeneration, and shadows) may conceal plant cover in the digital imagery. We asked whether vegetation complexity influences plant cover estimated by DIA relative to two visual methods: plot-level (20 m2) estimation (PLE) and quadrat-level (1 m2) estimation (QLE)? Location: Greater Yellowstone Ecosystem, USA. Methods: We estimated understorey plant cover in subalpine forest vegetation on permanent plots (n = 141) at two study areas ~30 years after the 1988 Yellowstone fires to: (a) assess differences in visual obstructions between study areas in our digital imagery; (b) compare digital to visual estimates of plant cover; and (c) determine relationships between estimated plant cover and visual obstructions measured in situ. Results: Percent conifer regeneration pixels differed significantly (odds ratio = 8.34) between study areas which represented the greatest difference in visual obstructions. At the study area with lower conifer pixels, DIA estimated 9% (95% confidence interval [CI] = 3%–14%) and 16% (95% CI = 10%–21%) more understorey plant cover than PLE or QLE, respectively, but had comparable variability. At the study area with higher conifer pixels, DIA estimated 28% (95% CI = 24%–32%) and 22% (95% CI = 18%–26%) less understorey plant cover than PLE or QLE, respectively, and had more variability. Furthermore, plot-level subcanopy regeneration (height>137 cm) density was negatively associated with digitally derived plant cover but showed no relationship with visually derived plant cover. Conclusions: Post-fire conifer regeneration hindered the efficacy of DIA in estimating understorey plant cover. Digital estimation is advantageous in single-strata vegetation but should not be used in complex, multi-strata vegetation. 相似文献
17.
Rebecca J. Cole Karen D. Holl Rakan A. Zahawi Philipp Wickey Alan R. Townsend 《Ecology and evolution》2016,6(15):5158-5168
Soil and litter arthropods represent a large proportion of tropical biodiversity and perform important ecosystem functions, but little is known about the efficacy of different tropical forest restoration strategies in facilitating their recovery in degraded habitats. We sampled arthropods in four 7‐ to 8‐year‐old restoration treatments and in nearby reference forests. Sampling was conducted during the wet and dry seasons using extractions from litter and pitfall samples. Restoration treatments were replicated in 50 × 50‐m plots in four former pasture sites in southern Costa Rica: plantation – trees planted throughout the plot; applied nucleation/islands – trees planted in patches of different sizes; and natural regeneration – no tree planting. Arthropod abundance, measures of richness and diversity, and a number of functional groups were greater in the island treatment than in natural regeneration or plantation treatments and, in many cases, were similar to reference forest. Litter and pitfall morphospecies and functional group composition in all three restoration treatments were significantly different than reference sites, but island and plantation treatments showed more recovery than natural regeneration. Abundance and functional group diversity showed a much greater degree of recovery than community composition. Synthesis and applications: The less resource‐intensive restoration strategy of planting tree islands was more effective than tree plantations in restoring arthropod abundance, richness, and functional diversity. None of the restoration strategies, however, resulted in similar community composition as reference forest after 8 years of recovery, highlighting the slow rate of recovery of arthropod communities after disturbance, and underscoring the importance of conservation of remnant forests in fragmented landscapes. 相似文献
18.
Xiao-Shuang Li Wen-Yao Liu Jun-Wen Chen Cindy Q. Tang Chun-Ming Yuan 《Journal of plant research》2010,123(6):751-762
Evergreen broad-leaved forest is now gradually degraded and fragmented, and there is an increase in the amount of habitat
edges as a result of long-term human activity. However, the role of edges in the regeneration of primary forest species is
poorly understood. After 20 years of the edge creation, we analyzed primary forest species distribution and abundance, and
changes in floristic composition, vegetation structure across forest-field gradients in Ailao Mountain, SW China. Our results
revealed that there was a higher abundance and richness of primary species, late secondary species and thorny lianas at the
distances 0–50 m than at the distances more than 50 m from the edge into the forest exterior. At the distances >50 m, no individuals
of dominant canopy trees Lithocarpus xylocarpus, Castanopsis wattii, and L. jingdongensis were found, whereas the abundance of early pioneer shrub species and herbaceous cover was significantly greater. The richness
of primary species showed a decrease with increasing distances from the forest edge to the exterior, particularly of medium-seeded
primary species showing a drastic decrease. Moreover, no large-seeded primary species occurred at the distances >60 m. This
study indicates that the forest edge as a buffer zone may be in favor of primary species regeneration. A dense shrub and herb
layer, and seed dispersal may be the major factors limiting the forest regeneration farther from the forest edge. Therefore,
to facilitate forest recovery processes, management should give priority to the protection of buffer zones of this forest
edge. 相似文献
19.
Rodrigo L. L. Orihuela Carlos A. Peres Gabriel Mendes Jo?o A. Jarenkow Marcelo Tabarelli 《PloS one》2015,10(8)
We examine the effects of forest fragmentation on the structure and composition of tree assemblages within three seasonal and aseasonal forest types of southern Brazil, including evergreen, Araucaria, and deciduous forests. We sampled three southernmost Atlantic Forest landscapes, including the largest continuous forest protected areas within each forest type. Tree assemblages in each forest type were sampled within 10 plots of 0.1 ha in both continuous forests and 10 adjacent forest fragments. All trees within each plot were assigned to trait categories describing their regeneration strategy, vertical stratification, seed-dispersal mode, seed size, and wood density. We detected differences among both forest types and landscape contexts in terms of overall tree species richness, and the density and species richness of different functional groups in terms of regeneration strategy, seed dispersal mode and woody density. Overall, evergreen forest fragments exhibited the largest deviations from continuous forest plots in assemblage structure. Evergreen, Araucaria and deciduous forests diverge in the functional composition of tree floras, particularly in relation to regeneration strategy and stress tolerance. By supporting a more diversified light-demanding and stress-tolerant flora with reduced richness and abundance of shade-tolerant, old-growth species, both deciduous and Araucaria forest tree assemblages are more intrinsically resilient to contemporary human-disturbances, including fragmentation-induced edge effects, in terms of species erosion and functional shifts. We suggest that these intrinsic differences in the direction and magnitude of responses to changes in landscape structure between forest types should guide a wide range of conservation strategies in restoring fragmented tropical forest landscapes worldwide. 相似文献
20.
Benjamin J. Adams Evan M. Gora Michiel van Breugel Sergio Estrada‐Villegas Stefan A. Schnitzer Jefferson S. Hall Stephen P. Yanoviak 《Biotropica》2019,51(6):885-893
Almost half of lowland tropical forests are at various stages of regeneration following deforestation or fragmentation. Changes in tree communities along successional gradients have predictable bottom‐up effects on consumers. Liana (woody vine) assemblages also change with succession, but their effects on animal succession remain unexplored. Here we used a large‐scale liana removal experiment across a forest successional chronosequence (7–31 years) to determine the importance of lianas to ant community structure. We conducted 1,088 surveys of ants foraging on and living in trees using tree trunk baiting and hand‐collecting techniques at 34 paired forest plots, half of which had all lianas removed. Ant species composition, β‐diversity, and species richness were not affected by liana removal; however, ant species co‐occurrence (the coexistence of two or more species in a single tree) was more frequent in control plots, where lianas were present, versus removal plots. Forest stand age had a larger effect on ant community structure than the presence of lianas. Mean ant species richness in a forest plot increased by ca. 10% with increasing forest age across the 31‐year chronosequence. Ant surveys from forest >20 years old included more canopy specialists and fewer ground‐nesting ant species versus those from forests <20 years old. Consequently, lianas had a minimal effect on arboreal ant communities in this early successional forest, where rapidly changing tree community structure was more important to ant species richness and composition. 相似文献