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1.
Throughout Pinus ponderosaPseudotsuga menziesii forests of the southern Colorado Front Range, USA, intense logging and domestic grazing began at the time of Euro-American settlement in the late 1800s and continued until the early 1900s. We investigated the long-term impacts of these settlement-era activities on understory plant communities by comparing understory composition at a historically logged and grazed site to that of an environmentally similar site which was protected from past use. We found that species richness and cover within functional groups rarely differed between sites in either upland or riparian areas. Multivariate analyses revealed little difference in species composition between sites on uplands, though compositional differences were apparent in riparian zones. Our findings suggest that settlement-era logging and grazing have had only minor long-term impacts on understories of upland Front Range P. ponderosaP. menziesii forests, though they have had a greater long-term influence on riparian understories, where these activities were likely the most intense. This article was written and prepared by US Government employees on official time, and therefore it is in the public domain and not subject to copyright.  相似文献   

2.
Previously extensive tracts of primary rain forest have been degraded by human activities, and we examined how the effects of forest disturbance arising from habitat fragmentation and commercial selective logging affected ecosystem functioning in these habitats by studying leaf litter decomposition rates in litter bags placed on the forest floor. The rain forests of Borneo are dominated by trees from the family Dipterocarpaceae, and we compared leaf litter decomposition rates of three dipterocarp species at eight forest fragment sites (area 3–3529 ha) that had different histories of disturbance pre‐fragmentation: four fragments had been selectively logged prior to fragmentation and four had been formed from previously undisturbed forest. We compared these logged and unlogged forest fragments with sites in continuous forest that had been selectively logged (two sites) and fully protected and undisturbed (two sites). After 120 d, undisturbed continuous forest sites had the fastest rates of decomposition (52% mass loss). Forest fragments formed from unlogged forest (32% mass loss) had faster decomposition rates than logged forest fragments (28% mass loss), but slower rates than continuous logged forest (39% mass loss). Leaves of a light‐demanding species (Parashorea malaanonan) decomposed faster than those of a shade‐tolerant species (Hopea nervosa), but decomposition of all three dipterocarp species that we studied responded similarly to logging and fragmentation effects. Reduced decomposition rates in logged and fragmented forest sites may affect nutrient cycling and thus have detrimental consequences for forest regeneration. Conservation management to improve forest quality should be a priority, particularly in logged forest fragments.  相似文献   

3.
Tropical rainforests are subject to extensive degradation by commercial selective logging. Despite pervasive changes to forest structure, selectively logged forests represent vital refugia for global biodiversity. The ability of these forests to buffer temperature‐sensitive species from climate warming will be an important determinant of their future conservation value, although this topic remains largely unexplored. Thermal buffering potential is broadly determined by: (i) the difference between the “macroclimate” (climate at a local scale, m to ha) and the “microclimate” (climate at a fine‐scale, mm to m, that is distinct from the macroclimate); (ii) thermal stability of microclimates (e.g. variation in daily temperatures); and (iii) the availability of microclimates to organisms. We compared these metrics in undisturbed primary forest and intensively logged forest on Borneo, using thermal images to capture cool microclimates on the surface of the forest floor, and information from dataloggers placed inside deadwood, tree holes and leaf litter. Although major differences in forest structure remained 9–12 years after repeated selective logging, we found that logging activity had very little effect on thermal buffering, in terms of macroclimate and microclimate temperatures, and the overall availability of microclimates. For 1°C warming in the macroclimate, temperature inside deadwood, tree holes and leaf litter warmed slightly more in primary forest than in logged forest, but the effect amounted to <0.1°C difference between forest types. We therefore conclude that selectively logged forests are similar to primary forests in their potential for thermal buffering, and subsequent ability to retain temperature‐sensitive species under climate change. Selectively logged forests can play a crucial role in the long‐term maintenance of global biodiversity.  相似文献   

4.
Tropical peat swamp forests (PSFs) are globally important carbon stores under threat. In Southeast Asia, 35% of peatlands had been drained and converted to plantations by 2010, and much of the remaining forest had been logged, contributing significantly to global carbon emissions. Yet, tropical forests have the capacity to regain biomass quickly and forests on drained peatlands may grow faster in response to soil aeration, so the net effect of humans on forest biomass remains poorly understood. In this study, two lidar surveys (made in 2011 and 2014) are compared to map forest biomass dynamics across 96 km2 of PSF in Kalimantan, Indonesia. The peatland is now legally protected for conservation, but large expanses were logged under concessions until 1998 and illegal logging continues in accessible portions. It was hypothesized that historically logged areas would be recovering biomass while recently logged areas would be losing biomass. We found that historically logged forests were recovering biomass near old canals and railways used by the concessions. Lidar detected substantial illegal logging activity—579 km of logging canals were located beneath the canopy. Some patches close to these canals have been logged in the 2011–2104 period (i.e. substantial biomass loss) but, on aggregate, these illegally logged regions were also recovering. Unexpectedly, rapid growth was also observed in intact forest that had not been logged and was over a kilometre from the nearest known canal, perhaps in response to greater aeration of surface peat. Comparing these results with flux measurements taken at other nearby sites, we find that carbon sequestration in above‐ground biomass may have offset roughly half the carbon efflux from peat oxidation. This study demonstrates the power of repeat lidar survey to map fine‐scale forest dynamics in remote areas, revealing previously unrecognized impacts of anthropogenic global change.  相似文献   

5.
The impact of logging on plant communities was studied in forest that has been logged selectively 1, 5 and 10 years previously (following a certified procedure): diversity was compared with that of primary rain forest in the Berau region of East Kalimantan, Indonesia. Four sets of 20 transects located within an area of 6 ha were sampled for all trees, saplings and seedlings, and records were made of topographic position, structure, composition and species diversity. There was a high level of floristic similarity between primary forests at the study sites compared to primary forest elsewhere in Kalimantan. The impact of logging is therefore likely to be the most important factor determining any differences between the plant communities of the selectively logged and primary forest sites. We found differences in species composition and abundance of most plants between selectively logged and primary forest. Overall, stem densities of trees in the primary forest were higher than in the three selectively logged forest sites. Stem densities of saplings were equivalent in all four forests. Seedling stem densities were higher in the forest site logged 10 years previously than in primary forest. Our results showed that the forests logged selectively under certified regimes still have a high plant diversity, possibly indicating that biodiversity values may be conserved by following certification procedures.  相似文献   

6.
K. S. Seshadri 《Biotropica》2014,46(5):615-623
Vast areas of tropical evergreen forests have been selectively logged in the past, and many areas continue to be logged. The impacts of such logging on amphibians are poorly understood. I examined the response of anuran communities to historical selective logging in a wet evergreen forest in south India. Anuran assemblages in unlogged forest were compared with assemblages in selectively logged forest. Forty 10 m × 10 m quadrats in forest, riparian zones, and streams of unlogged and selectively logged forests were searched at night for anurans. Species richness did not appear to be affected by logging. However, anuran density varied significantly and was 42 percent lower in selectively logged forests compared to unlogged forests. Anuran densities also varied significantly across microhabitats, with highest densities in streams of both selectively logged and unlogged forests. Patterns of niche overlap varied with selective logging as niche breadth either expanded, contracted, or remained neutral for different species. Ordination analysis explained 95 percent of the variation in species assemblage across selectively logged and unlogged forests. The assemblage in selectively logged forest was nested within unlogged forest. Among the habitat characteristics, litter thickness and water depth had the highest influence on the assemblage. This was followed by litter/water temperature, air temperature, and lastly relative humidity. It appears that species richness and composition of anurans in selectively logged forests is converging with unlogged forests, but the effects of historical logging seem to persist on anuran densities and their niche characteristics even ca 40 yr since logging ceased.  相似文献   

7.
Plinio Sist  Ervan Rutishauser  Marielos Peña-Claros  Alexander Shenkin  Bruno Hérault  Lilian Blanc  Christopher Baraloto  Fidèle Baya  Fabrice Benedet  Katia Emidio da Silva  Laurent Descroix  Joice Nunes Ferreira  Sylvie Gourlet-Fleury  Marcelino Carneiro Guedes  Ismail Bin Harun  Riina Jalonen  Milton Kanashiro  Haruni Krisnawati  Mrigesh Kshatriya  Philippa Lincoln  Lucas Mazzei  Vincent Medjibé  Robert Nasi  Marcus Vinicius N. d'Oliveira  Luis C. de Oliveira  Nicolas Picard  Stephan Pietsch  Michelle Pinard  Hari Priyadi  Francis. E. Putz  Ken Rodney  Vivien Rossi  Anand Roopsind  Ademir Roberto Ruschel  Nur Hajar Zamah Shari  Cintia Rodrigues de Souza  Farida Herry Susanty  Eleneide Doff Sotta  Marisol Toledo  Edson Vidal  Thales A.P. West  Verginia Wortel  Toshihiro Yamada 《应用植被学》2015,18(1):171-174
While attention on logging in the tropics has been increasing, studies on the long-term effects of silviculture on forest dynamics and ecology remain scare and spatially limited. Indeed, most of our knowledge on tropical forests arises from studies carried out in undisturbed tropical forests. This bias is problematic given that logged and disturbed tropical forests are now covering a larger area than the so-called primary forests. A new network of permanent sample plots in logged forests, the Tropical managed Forests Observatory (TmFO), aims to fill this gap by providing unprecedented opportunities to examine long-term data on the resilience of logged tropical forests at regional and global scales. TmFO currently includes 24 experimental sites distributed across three tropical regions, with a total of 490 permanent plots and 921 ha of forest inventories.  相似文献   

8.
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   

9.
Effects of forest management on stream communities have been widely documented, but the role that climate plays in the disturbance outcomes is not understood. In order to determine whether the effect of disturbance from forest management on headwater stream communities varies by climate, we evaluated benthic macroinvertebrate communities in 24 headwater streams that differed in forest management (logged-roaded vs. unlogged-unroaded, hereafter logged and unlogged) within two ecological sub-regions (wet versus dry) within the eastern Cascade Range, Washington, USA. In both ecoregions, total macroinvertebrate density was highest at logged sites (P = 0.001) with gathering-collectors and shredders dominating. Total taxonomic richness and diversity did not differ between ecoregions or forest management types. Shredder densities were positively correlated with total deciduous and Sitka alder (Alnus sinuata) riparian cover. Further, differences in shredder density between logged and unlogged sites were greater in the wet ecoregion (logging × ecoregion interaction; P = 0.006) suggesting that differences in post-logging forest succession between ecoregions were responsible for differences in shredder abundance. Headwater stream benthic community structure was influenced by logging and regional differences in climate. Future development of ecoregional classification models at the subbasin scale, and use of functional metrics in addition to structural metrics, may allow for more accurate assessments of anthropogenic disturbances in mountainous regions where mosaics of localized differences in climate are common.  相似文献   

10.
Pericopsis elata (Fabaceae) is a tall tree of high commercial value of the moist semi‐deciduous African forests. As a result of decades of logging it is now considered as threatened and listed on the IUCN Red List and CITES Appendix II, even though essential biological parameters controlling its population dynamics remain unknown. This study aims at improving the knowledge of the species' ecological parameters, and at assessing the impact of selective logging on its populations in an 118,052 ha forest in Cameroon. After inventorying the species in 1432 ha, mortality and growth were assessed over continuous 5‐ and 2‐yr periods in unlogged and logged areas, respectively. Phenology was monitored in the unlogged forest during 5 yr. The population structure shows high relative abundance of trees in medium size categories. Mean annual diameter increments in both environments did not differ significantly between unlogged and logged areas. P. elata is a deciduous species that flowers at the end of the main dry season. The minimum reproduction and effective flowering diameters were 32 and 37 cm, respectively. Fruit maturation took place during 7 mo. With a minimum logging diameter of 90 cm, the recovery rate computed over a 30‐yr period was > 100 percent. Selective logging harvested only 12.1 percent of the total number of seed trees and had little influence on the species' biological parameters. Securing sufficient regeneration as a post‐logging action is probably the most important consideration for achieving long‐term sustainability.  相似文献   

11.
The carabid beetle species assemblages (14 sample sites) of a 238 ha urban oak forest in Trieste, Italy, studied in 1983–84 with pitfall traps, were compared with an historic list of 57 species hand collected by entomologists in the same forest before it was logged in 1944.Trap data have been improved by hand collections to get a species list as complete as the historic one. Multivariate analysis was used to group the sites (14 plus the historic list) into three assemblages of brooks, clearings and forests. After the Second World War logging, the secondary ecological succession resulted in a lower species number, with a trend to a new equilibrium. Some important forest specialists, such as Laemostenus venustus, have been lost. Human pressure and recolonisation by carabids are still occurring. The in situ extinction of ground beetles near the end of the last century reached values between 57 and 64% of the species historically recorded. Consequently, urgent restoration measures are required for waterside habitats, forest and land management, to maintain small open areas or clearings. The study of carabid species assemblages and habitat affinities seems a useful tool for adaptive management of forests affected by human activities, because changes in carabid species number and type can be easily related to human disturbance.  相似文献   

12.
In the present work we examined the composition and distribution across three soil layers of the buried soil seed bank under three different overstory types (Fagus sylvatica, Quercus robur, Pinus sylvestris) and in logging areas in a 4383-ha forest in central Belgium. The objectives were: (1) to investigate whether species composition and species richness of soil seed banks are affected by different forest stands; (2) to examine how abundant are habitat-specific forest species in seed banks under different planted tree layers. The study was carried out in stands which are replicated, managed in the same way (even-aged high forest), and growing on the same soil type with the same land-use history. In the investigated area, the seed bank did show significant differences under oak, beech, pine and in logging areas, respectively in terms of size, composition and depth occurrence. All species and layers taken together, the seed bank size ranked as follows: oakwood > beechwood > logging area > pinewood. The same pattern was found for forest species. Seed numbers of Betula pendula, Calluna vulgaris, Dryopteris dilatata and Rubus fruticosus were significantly higher under the beech canopy. Carex remota, Impatiens parviflora and Lotus sp. showed a significantly denser seed bank in logging areas, while Digitalis purpurea seeds were significantly more abundant in soils under the oak canopy. The fact that the seed bank of an originally homogeneous forest varies under different planted stands highlights that a long period of canopy conversion can affect the composition and depth of buried seeds.  相似文献   

13.
To examine the effects of selective timber extraction on fish communities in Sabah, Malaysia, quantitative samples of fishes were taken from thirteen streams running through undisturbed rainforest or through forest that had been selectively logged 3–18 years previously. Multivariate analysis (canonical discriminant analysis and cluster analysis) indicated that mesohabitats within streams (riffles and pools) and differences in stream size were more important in determining community structure than logging history. Riffles in streams running through logged or undisturbed forest were indistinguishable using relative biomass or abundance data, as were pools from small streams (approximate order 2). Fish communities from pools in larger streams showed some separation in multivariate space corresponding to a complex set of relative changes in abundance and/or biomass between species. However it was difficult to unambiguously assign such changes to logging regime alone. There appeared to be some differences in fish communities between streams in recently-logged (3–7 years) and old-logged (17–18 years) areas related to abundance or biomass of three cyprinids (Garra borneensis, Lobocheilos bo and Osteochilus chini). Only one species, Pangio mariarum, was not found in streams in logged forest, but it was only found at one location in undisturbed forest. A number of other species showed significant differences in abundance or biomass between sites but most of these were only present at some sites and in low abundance. Principal components analysis of habitat data showed that riffle sites were homogeneous whatever their logging history as were pools in unlogged large streams. Pools in logged large streams were significantly more heterogeneous but in a random rather than systematic manner. It is concluded that the type of selective logging practices used locally have low impact on fish communities through mechanisms of persistence and/or rapid recolonisation.  相似文献   

14.
The impact of logging and subsequent recovery after logging is predicted to vary depending on specific life history traits of the logged species. The Eco-gene simulation model was used to evaluate the long-term impacts of selective logging over 300 years on two contrasting Brazilian Amazon tree species, Dipteryx odorata and Jacaranda copaia. D. odorata (Leguminosae), a slow growing climax tree, occurs at very low densities, whereas J. copaia (Bignoniaceae) is a fast growing pioneer tree that occurs at high densities. Microsatellite multilocus genotypes of the pre-logging populations were used as data inputs for the Eco-gene model and post-logging genetic data was used to verify the output from the simulations. Overall, under current Brazilian forest management regulations, there were neither short nor long-term impacts on J. copaia. By contrast, D. odorata cannot be sustainably logged under current regulations, a sustainable scenario was achieved by increasing the minimum cutting diameter at breast height from 50 to 100 cm over 30-year logging cycles. Genetic parameters were only slightly affected by selective logging, with reductions in the numbers of alleles and single genotypes. In the short term, the loss of alleles seen in J. copaia simulations was the same as in real data, whereas fewer alleles were lost in D. odorata simulations than in the field. The different impacts and periods of recovery for each species support the idea that ecological and genetic information are essential at species, ecological guild or reproductive group levels to help derive sustainable management scenarios for tropical forests.  相似文献   

15.
Tropical rain forests worldwide are affected by anthropogenic disturbances, and secondary forests that develop afterwards are often dominated by pioneer tree species, but the consequences of different anthropogenic disturbances on nutrient cycling are poorly understood. Because most nutrient cycling in tropical rain forests occurs through litterfall and in the soil organic layer, we measured litterfall of a widespread and dominant pioneer tree, okoume (Aucoumea klaineana, Burseraceae) in Gabon, in one forest previously disturbed by logging and in another by agriculture. Litterfall of okoume trees, measured over 14 months, was 18.2 Mg ha−1 year−1 in the formerly logged forest, which was 72.6% greater than in the forest more recently disturbed by agriculture (10.6 Mg ha−1 year−1). Litter decomposition rates were more rapid in the formerly logged forest, and this may explain why litter thickness was 32% lower in the formerly logged forest, despite the greater litterfall within it. Our results highlight that two widespread anthropogenic disturbances in Gabonese rain forests have significantly different consequences on litterfall of a dominant tree and therefore are likely to have different effects on nutrient cycling and forest ecosystem function.  相似文献   

16.
We compared bird diversity and frequency in selection logged and unlogged forest to determine the effects of recent selection logging on avian biodiversity in a subtropical, moist evergreen forest. We used a combination of mist netting and fixed-radius point counts to assess bird communities in February and March 1993 in northwestern Belize. Vegetation structure and composition was similar in logged and unlogged forest. The 66 most common species occurred with statistically similar frequency in logged and unlogged forest although 13 species were two times more frequent in intact forest. Numbers of total bird species were similar between logging gaps and the logged forest matrix, and between the logged forest matrix and unlogged forests. A comparison of numbers of species in 26 guilds based on migration strategy, diet, foraging substrate, and height strata also showed them to be similar regardless of logging history. Our results differed from previous studies that reported lower bird species richness and abundance of individual species in logged tropical forests than in unlogged forest. The differences might be explained by the lower logging intensity and/or greater levels of natural disturbance in our study area compared to previous studies.  相似文献   

17.
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   

18.
Temperature is a core component of a species' fundamental niche. At the fine scale over which most organisms experience climate (mm to ha), temperature depends upon the amount of radiation reaching the Earth's surface, which is principally governed by vegetation. Tropical regions have undergone widespread and extreme changes to vegetation, particularly through the degradation and conversion of rainforests. As most terrestrial biodiversity is in the tropics, and many of these species possess narrow thermal limits, it is important to identify local thermal impacts of rainforest degradation and conversion. We collected pantropical, site‐level (<1 ha) temperature data from the literature to quantify impacts of land‐use change on local temperatures, and to examine whether this relationship differed aboveground relative to belowground and between wet and dry seasons. We found that local temperature in our sample sites was higher than primary forest in all human‐impacted land‐use types (N = 113,894 daytime temperature measurements from 25 studies). Warming was pronounced following conversion of forest to agricultural land (minimum +1.6°C, maximum +13.6°C), but minimal and nonsignificant when compared to forest degradation (e.g., by selective logging; minimum +1°C, maximum +1.1°C). The effect was buffered belowground (minimum buffering 0°C, maximum buffering 11.4°C), whereas seasonality had minimal impact (maximum buffering 1.9°C). We conclude that forest‐dependent species that persist following conversion of rainforest have experienced substantial local warming. Deforestation pushes these species closer to their thermal limits, making it more likely that compounding effects of future perturbations, such as severe droughts and global warming, will exceed species' tolerances. By contrast, degraded forests and belowground habitats may provide important refugia for thermally restricted species in landscapes dominated by agricultural land.  相似文献   

19.
In the U.S., high elevation spruce-fir forests receive greater amounts of nitrogen deposition relative to low elevation areas. At high elevations the cycling of nitrogen is naturally low due to slower decomposition and low biological N demand. The combination of these factors make spruce-fir ecosystems potentially responsive to changes in N inputs.Excess nitrogen deposition across the northeastern United States and Europe has provided an opportunity to observe ecosystem response to changing N inputs. Effects on foliar and forest floor chemistry were examined in a field study of 161 spruce-fir sites across a longitudinal (west-to-east) N deposition gradient. Both foliar elemental concentrations and forest floor elemental concentrations and rates of potential N mineralization were correlated with position along this gradient.Nitrogen deposition was positively correlated with potential forest floor nitrification and mineralization, negatively correlated with forest floor C:N and Mg concentrations and with spruce foliar lignin, lignin:N and Mg:N ratios. Foliar lignin:N and forest floor C:N were positively correlated and both were negatively correlated with nitrification and mineralization. Correlations found between forest floor and foliar N and Mg concentrations support the theory of nutrient imbalance as a potential cause of forest decline.  相似文献   

20.
Primates often live in human-altered habitats; Malagasy lemurs are no exception. It is important to understand if habitat alteration affects primates’ space use patterns across multiple spatial and temporal scales, as this drives population density. We quantified the daily, seasonal, and annual space-use of seven groups of Milne-Edwards’ sifaka (Propithecus edwardsi) living in unlogged and logged rain forest in Ranomafana National Park, Madagascar between December 2002 and November 2003. Concurrent data showed that sifakas consumed higher quality foods in the unlogged than in logged forests; thus we explored how space use patterns were related to energy use strategies. Sifaka groups in the logged rain forest traveled 7–13% less per day than groups in the unlogged rain forest, despite their larger home ranges (median: 46.12 and 23.52 ha, in the logged and unlogged forests, respectively). Sifakas may thus use an energy-minimizing strategy at the scale of the individual day but an energy-maximizing strategy at the annual home range scale. Sifakas exhibited fidelity to the home range across seasons, but their core area of use shifted considerably with season. We found no difference in population density between sites. However, given the interannual variability in sifaka foods, a multiyear study is needed to assess if energy strategies observed in this study are consistent across longer time periods. Our findings suggest that lemurs may persist in logged habitats by altering spatial use patterns; future work should attempt to quantify the threshold level of forest regeneration from logging that will allow lemurs to persist at similar densities as in unlogged forest.  相似文献   

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