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1.
Habitat quality is more important than matrix quality for bird communities in protected areas
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Matti Häkkilä Nerea Abrego Otso Ovaskainen Mikko Mönkkönen 《Ecology and evolution》2018,8(8):4019-4030
Protected areas are meant to preserve native local communities within their boundaries, but they are not independent from their surroundings. Impoverished habitat quality in the matrix might influence the species composition within the protected areas through biotic homogenization. The aim of this study was to determine the impacts of matrix quality on species richness and trait composition of bird communities from the Finnish reserve area network and whether the communities are being subject of biotic homogenization due to the lowered quality of the landscape matrix. We used joint species distribution modeling to study how characteristics of the Finnish forest reserves and the quality of their surrounding matrix alter species and trait compositions of forest birds. The proportion of old forest within the reserves was the main factor in explaining the bird community composition, and the bird communities within the reserves did not strongly depend on the quality of the matrix. Yet, in line with the homogenization theory, the beta‐diversity within reserves embedded in low‐quality matrix was lower than that in high‐quality matrix, and the average abundance of regionally abundant species was higher. Influence of habitat quality on bird community composition was largely explained by the species' functional traits. Most importantly, the community specialization index was low, and average body size was high in areas with low proportion of old forest. We conclude that for conserving local bird communities in northern Finnish protected forests, it is currently more important to improve or maintain habitat quality within the reserves than in the surrounding matrix. Nevertheless, we found signals of bird community homogenization, and thus, activities that decrease the quality of the matrix are a threat for bird communities. 相似文献
2.
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
3.
Butterfly populations in two forest fragments at the Kenya coast 总被引:4,自引:0,他引:4
Species richness, diversity and composition of butterflies in two Kenya coastal forest remnants, Muhaka and Mrima hill, were investigated. Sixty‐three species were recorded from each forest remnant from a total of 1329 individuals. Species accumulation curves for both forests did not reach an asymptote. High species similarity was recorded between the forest interior and the surrounding matrix, primarily due to invasion of the forest interior clearings by the savanna species. Despite their small sizes, these forest remnants were found to maintain viable populations of true forest butterflies. However, the number of species was less than half that recorded from the larger forest reserve of Arabuko‐Sokoke, located in the same geographical area. Records from Muhaka forest show species unique to it, not found in the larger forest reserves, underscoring the importance of small remnants in the preservation of forest biodiversity. The high species similarity between the forest remnants implied that if habitat corridors were created, gene flow between these remnants and other larger forest reserves would be possible. This would reduce the isolation of true forest butterfly populations within the remnants and potential local extinction. 相似文献
4.
The spider faunas of two savannah reserves along the eastern coastal plain of Africa are compared. Species richness was higher in the tropical area, with 493 species (54 families) from Mkomazi Game Reserve, Tanzania. Species richness was also high in the subtropics, with a total of 431 species (46 families) recorded from Ndumo Game Reserve, South Africa. Spider community structure was remarkably similar in the two reserves, with Salticidae, Gnaphosidae, Thomisidae, Theridiidae and Araneidae the most species‐rich families in both reserves. Eleven of the fourteen most species rich families were the same. A similar proportion of families were represented by singleton and doubleton species. A genus‐ and species‐level comparison of ten spider families indicates that while there is considerable overlap in the generic composition of the reserves (Sorensen’s Quotient of similarity: all >0.650 except Linyphiidae, 0.166; Corinnidae, 0.500) there is little overlap between the species occurring in the two sites (0.000–0.571), which was particularly evident in the more species‐rich families. A comparison of diversity of 57 families in each reserve with the spider biodiversity in the two sub‐regions suggests that local biodiversity is largely determined by regional biogeographical influences rather than local ecological factors. 相似文献
5.
Do riparian reserves support dung beetle biodiversity and ecosystem services in oil palm-dominated tropical landscapes?
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Claudia L. Gray Eleanor M. Slade Darren J. Mann Owen T. Lewis 《Ecology and evolution》2014,4(7):1049-1060
Agricultural expansion and intensification are major threats to global biodiversity, ecological functions, and ecosystem services. The rapid expansion of oil palm in forested tropical landscapes is of particular concern given their high biodiversity. Identifying management approaches that maintain native species and associated ecological processes within oil palm plantations is therefore a priority. Riparian reserves are strips of forest retained alongside rivers in cultivated areas, primarily for their positive hydrological impact. However, they can also support a range of forest‐dependent species or ecosystem services. We surveyed communities of dung beetles and measured dung removal activity in an oil palm‐dominated landscape in Sabah, Malaysian Borneo. The species richness, diversity, and functional group richness of dung beetles in riparian reserves were significantly higher than in oil palm, but lower than in adjacent logged forests. The community composition of the riparian reserves was more similar to logged forest than oil palm. Despite the pronounced differences in biodiversity, we did not find significant differences in dung removal rates among land uses. We also found no evidence that riparian reserves enhance dung removal rates within surrounding oil palm. These results contrast previous studies showing positive relationships between dung beetle species richness and dung removal in tropical forests. We found weak but significant positive relationships between riparian reserve width and dung beetle diversity, and between reserve vegetation complexity and dung beetle abundance, suggesting that these features may increase the conservation value of riparian reserves. Synthesis and applications: The similarity between riparian reserves and logged forest demonstrates that retaining riparian reserves increases biodiversity within oil palm landscapes. However, the lack of correlation between dung beetle community characteristics and dung removal highlights the need for further research into spatial variation in biodiversity–ecosystem function relationships and how the results of such studies are affected by methodological choices. 相似文献
6.
J. L. Bossart E. Opuni-Frimpong S. Kuudaar E. Nkrumah 《Biodiversity and Conservation》2006,15(1):333-359
Sacred forest groves in Ghana are centuries old protected areas that were once part of continuous forest cover but now mostly
exist as relict forest patches embedded in an agropastoral landscape. We conducted a year-long survey of the fruit-feeding
butterfly fauna of four sacred groves and two forest reserves in the moist semi-deciduous forest zone of Ghana to characterize
resident species diversity and complementarity among communities. Joint analysis of frugivorous butterfly diversity at these
six forest fragments, which ranged in size from 6 to 5000 ha, was used to evaluate the conservation potential of these ancient
indigenous reserves. A total of 6836 individuals were trapped across all sites, representing 79 species and five subfamilies.
Community diversity was characterized in terms of, (a) number of species accumulated versus sampling effort, (b) rarefied
species richness, (c) nonparametric richness estimates, (d) species evenness, (e) Simpson’s Index of Diversity, and (f) complementarity
of communities. Diversity of the fruit-feeding butterfly communities, quantified in terms of both species evenness and rarefied
species richness, was higher at the larger forest reserves than at the small sacred forest groves. Additionally, although
all sites had species trapped only at that site, the 5000-ha forest reserve harbored a resident community that was clearly
distinctive from and more diverse than the other communities including the other forest reserve. Hence, our findings add to
the burgeoning body of data that indicates large reserves are the foundation of successful conservation programs. Nonetheless,
we found these small forest patches contribute to biodiversity conservation in at least three ways and these are identified
and discussed. We also identify a number of species that appear more or less vulnerable to dynamics of forest fragmentation
based on changes in their relative abundance across sites and we interpret these data in the context of potential indicator
species and theoretical predictions of at-risk species. 相似文献
7.
Aim To investigate the relative role of local versus landscape factors for local species diversity of snails and slugs in conservation forests. In landscapes with small, isolated patches of semi‐natural habitats, many species that require large habitat areas have disappeared or are threatened. We asked whether small sedentary taxa that depend on local conditions, such as molluscs, are affected if total habitat area decreases in the landscape. Location Temperate broadleaved and oak‐rich forest in southern Sweden. Methods We sampled molluscs in 25 small conservation forests that are well‐spaced out over a large region. In each forest, sampling was conducted in two plots, each of 1 ha, separated by about 25–100 m. Factors potentially influencing local diversity of molluscs were measured in the plots and in the surrounding landscape at different scales (in space and time) and were analysed by stepwise multiple regression and ordination (PCA and NMS). Results We recorded 53 species, and mean species richness per forest (plots pooled) was 22.6. The pH of the plant litter predicted both species richness and composition; other local (plot) factors of lower importance were canopy openness, stony ground and tree species. The area of conservation forest (woodland key habitat) within 10 km of plots was positively associated with species richness, and was also related to species composition. Openness of the landscape (agriculture) was a negative factor, but historical plot openness (1938–59) seemed to be unimportant. In addition, climate/topography (temperature and altitude) also predicted species composition of the sites. Main conclusions We rejected the hypothesis that microhabitat factors alone, or mainly, determine local species richness and composition of land molluscs. These representatives of small, sedentary organisms seem to be substantially influenced by the surrounding landscape, which should be considered in conservation work and in plans for the protection of forest biodiversity. 相似文献
8.
Protection from fishing generally results in an increase in the abundance and biomass of species targeted by fisheries within
marine reserve boundaries. Natural refuges such as depth may also protect such species, yet few studies in the Indo Pacific
have investigated the effects of depth concomitant with marine reserves. We studied the effects of artisanal fishing and depth
on reef fish assemblages in the Kubulau District of Vanua Levu Island, Fiji, using baited remote underwater stereo-video systems.
Video samples were collected from shallow (5–8 m) and deep (25–30 m) sites inside and outside of a large old marine reserve
(60.6 km2, 13 years old) and a small new marine reserve (4.25 km2, 4 years old). Species richness tended to be greater in the shallow waters of the large old reserve when compared to fished
areas. In the deeper waters, species richness appeared to be comparable. The difference in shallow waters was driven by species
targeted by fisheries, indicative of a depth refuge effect. In contrast, differences in the abundance composition of the fish
assemblage existed between protected and fished areas for deep sites, but not shallow. Fish species targeted by local fisheries
were 89% more abundant inside the large old reserve than surrounding fished areas, while non-targeted species were comparable.
We observed no difference in the species richness or abundance of species targeted by fisheries inside and outside of the
small new reserve. This study suggests that artisanal fishing impacts on the abundance and species richness of coral reef
fish assemblages and effects of protection are more apparent with large reserves that have been established for a long period
of time. Observed effects of protection also vary with depth, highlighting the importance of explicitly incorporating multiple
depth strata in studies of marine reserves. 相似文献
9.
Jeffrey R. Dunk William J. Zielinski Hartwell H. Welsh Jr 《Diversity & distributions》2006,12(4):434-442
The Klamath‐Siskiyou forests of northern California and southern Oregon are recognized as an area of globally outstanding biological distinctiveness. When evaluated at a national or global level, this region is often, necessarily, considered to be uniformly diverse. Due to large variation in biotic and abiotic variables throughout this region, however, it is unlikely that biological diversity is uniformly distributed. Furthermore, land management decisions nearly always occur at spatial scales smaller than this entire region. Therefore, we used field data from a random sampling design to map the distribution of local and regional richness of terrestrial molluscs and salamanders within northern California's portion of the Klamath‐Siskiyou region. We also evaluated the protection afforded by reserves established for varying reasons (e.g. for inspiration and recreation for people vs. species conservation) to hotspots of species richness and species representation of these taxa. No existing reserves were created with these taxa in mind, yet it was assumed that reserves established largely around considerations for the northern spotted owl (Strix occidentalis caurina) would afford adequate protection for many lesser‐known species. Species of terrestrial molluscs and salamanders share two general features: (1) they have extremely low vagility, and (2) they are often associated with moist, cool microclimates. Existing reserves disproportionately included areas of hotspots of species richness for both taxa, when hotspots included the richest c. 25% of the area, whereas non‐reserved lands contained greater than expected areas with lower species richness. However, when a more strict definition of hotspot was used (i.e. the richest c.10% of areas), local hotspots for both taxa were not disproportionately found in reserves. Reserves set aside largely for human aesthetics and recreation and those set aside for biodiversity both contributed to the protection of areas with high (greatest 25%) species richness. Existing biodiversity reserves represented 68% of mollusc species and 73% of salamander species, corresponding to the 99th and 93rd percentiles, respectively, of species representation achieved by simulating a random distribution of the same total area of reservation. Cumulatively, however, reserves set aside for inspiration and biodiversity represented 83% of mollusc species and 91% of salamander species. The existing reserves provide conservation value for terrestrial molluscs and salamanders. This reserve network, however, should not be considered optimal for either taxa. 相似文献
10.
Recovery of Amphibian and Reptile Assemblages During Old‐Field Succession of Tropical Rain Forests
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Conversion of tropical forests to agriculture affects vertebrate assemblages, but we do not know how fast or to what extent these assemblages recover after field abandonment. We addressed this question by examining amphibians and reptiles in secondary forests in southeastern Mexico. We used chronosequence data (12 secondary forests fallow for 1–23 yr and 3 old‐growth forest sites) to analyze successional trajectories and estimate recovery times of assemblage attributes for amphibians and reptiles. We conducted 6 surveys at each site over 14 mo (1200 person‐hours) and recorded 1552 individuals, including 25 species of amphibians and 36 of reptiles, representing 96 and 74 percent of the expected regional number of species, respectively. Abundance, species richness, and species diversity of amphibians increased rapidly with successional age, approaching old‐growth forest values in < 30 yr. Species richness and species diversity of reptiles reached old‐growth forest values in < 20 yr. By contrast, the abundance of reptiles and the assemblage composition of amphibians and reptiles recovered more slowly. Along the chronosequence, we observed more species replacement in reptile assemblages than in amphibian assemblages. Several species in the old‐growth forest were absent from secondary forests. Dispersal limitation and harsh conditions prevailing in open sites and early successional environments appear to preclude colonization by old‐growth forest species. Furthermore, short fallow periods and isolation of forest remnants lead to the formation of new assemblages dominated by species favored by human disturbances. 相似文献
11.
江西井冈山自然保护区陆生贝类多样性 总被引:1,自引:0,他引:1
2011年4~8月调查了江西井冈山自然保护区陆生贝类资源,共采得陆生贝类67种和亚种(含9个未定种),隶属4目19科31属,其中有1新种,即龙潭弯螺(Sinoennea sp.nov.)(另文报道);14种为江西省陆生贝类新纪录种;优势种为长柱倍唇螺(Diplommatina paxillus longipalatalis)、细锥倍唇螺(D.apicina)、灰尖巴蜗牛(Bradybaena ravida ravida)、双线巨蓬蛞蝓(Meghimatium bilineatum)。区系组成以东洋界成分为主,占种类总数的74.14%。阔叶林、灌木丛和农田生境陆生贝类种类较丰富,竹林和苔藓生境种类较少。根据调查数据,分别计算井冈山自然保护区5种不同生境类型中陆生贝类群落的多样性、丰富度和均匀度,结果表明,灌木丛生境陆生贝类的丰富度指数和多样性指数均最高,苔藓生境的均匀度指数最高。与邻近自然保护区比较,井冈山自然保护区陆生贝类物种较丰富,且与江西齐云山陆生贝类物种相似系数较高,与广东南岭物种相似系数较低。 相似文献
12.
Enock Ssekuubwa Vincent B. Muwanika Josephine Esaete John R. S. Tabuti Mnason Tweheyo 《Restoration Ecology》2019,27(1):148-157
The status of woody seedling colonization gives clues about the self‐sustainability of restored forests, a tenet of restoration success. Little is known about woody seedling colonization in restored afrotropical forests. We evaluated effects of restoration methods (active vs. passive), sampling year, restoration age, and distance from old‐growth forests on seedling colonization in restored afrotropical moist forests. Seedlings were measured in 2011 and 2014 in 71 clusters of 284 permanent sampling plots (12.6 m2 each) in actively (initially 3–16 years old) and 21 clusters of 63 plots in passively restored forests (initially 16 years old) in Kibale National Park, western Uganda. Seedlings were also measured in nearby old‐growth forests in three clusters of five plots in 2014. We determined species diversity, richness, abundance per plot, and species composition as measures of seedling colonization in restored and old‐growth forests. We found that diversity, richness, and abundance of seedlings were significantly higher in passively than actively restored forests. Diversity and richness but not abundance significantly increased between sampling years and with restoration age. Distance from old‐growth forests did not significantly affect diversity, richness, and abundance. Species composition of actively and passively restored forests was different from that of old‐growth forests after 19 years since restoration started. Our results show that passive restoration should be the preferred method for recovering afrotropical forests, and highlight the effect of continued management on biodiversity of restored forests. 相似文献
13.
Recovery of mammal diversity in tropical forests: a functional approach to measuring restoration
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Mia A. Derhé Helen T. Murphy Noel D. Preece Michael J. Lawes Rosa Menéndez 《Restoration Ecology》2018,26(4):778-786
Ecological restoration is increasingly applied in tropical forests to mitigate biodiversity loss and recover ecosystem functions. In restoration ecology, functional richness, rather than species richness, often determines community assembly, and measures of functional diversity provide a mechanistic link between diversity and ecological functioning of restored habitat. Vertebrate animals are important for ecosystem functioning. Here, we examine the functional diversity of small‐to‐medium sized mammals to evaluate the diversity and functional recovery of tropical rainforest. We assess how mammal species diversity and composition and functional diversity and composition, vary along a restoration chronosequence from degraded pasture to “old‐growth” tropical rainforest in the Wet Tropics of Australia. Species richness, diversity, evenness, and abundance did not vary, but total mammal biomass and mean species body mass increased with restoration age. Species composition in restoration forests converged on the composition of old‐growth rainforest and diverged from pasture with increasing restoration age. Functional metrics provided a clearer pattern of recovery than traditional species metrics, with most functional metrics significantly increasing with restoration age when taxonomic‐based metrics did not. Functional evenness and dispersion increased significantly with restoration age, suggesting that niche complementarity enhances species' abundances in restored sites. The change in community composition represented a functional shift from invasive, herbivorous, terrestrial habitat generalists and open environment specialists in pasture and young restoration sites, to predominantly endemic, folivorous, arboreal, and fossorial forest species in older restoration sites. This shift has positive implications for conservation and demonstrates the potential of tropical forest restoration to recover rainforest‐like, diverse faunal communities. 相似文献
14.
Ernesto Gianoli Alfredo Saldaña Mylthon Jiménez‐Castillo Fernando Valladares 《植被学杂志》2010,21(1):66-73
Question: Are vines light‐demanding species? Location: Temperate evergreen rain forest of southern Chile (40°39′S, 72°11′W). Methods: In 45 plots of 25 m2 distributed in treefall canopy gaps, secondary forest stands and old‐growth forest (15 plots per light environment), all climbing and non‐supported vines were counted and identified to species level, and canopy openness was quantified using hemispherical photographs. Vine abundance and diversity (species richness and Simpson's index) were compared in the three light environments and similarity between vine communities was estimated using Jaccard's similarity coefficient. We also determined the relationship between light niche breadth and local dominance at the species level. Results: In total there were 2510 vine individuals of 14 species. Canopy openness was significantly different in the three light environments. Species richness, diversity, community composition and density of vines were similar in treefall gaps, secondary and old‐growth forest. Of the seven more common vine species, which accounted for 91% of all vines, three had even distribution, two were more abundant in the shaded understorey, and two had higher density in well‐lit sites. Local dominance of vine species and niche breadth were not significantly associated. Conclusions: Our study in a temperate rain forest questions the widespread notion of vines as pioneer‐like species, which may be a consequence of the abundance of some lianas in disturbed sites of tropical forests. Functional arguments are needed to justify a general hypothesis on light requirements of vines, which constitute a vast group of species. 相似文献
15.
Question: Can augmented forest stand complexity increase understory vegetation richness and cover and accelerate the development of late‐successional features? Does within‐stand understory vegetation variability increase after imposing treatments that increase stand structural complexity of the overstory? What is the relative contribution of individual stand structural components (i.e. forest matrix, gaps, and leave island reserves) to changes in understory vegetation richness? Location: Seven study sites in the Coastal Range and Cascades regions of Oregon, USA. Methods: We examined the effects of thinning six years after harvest on understory plant vascular richness and cover in 40‐ to 60‐year‐old forest stands dominated by Douglas‐fir (Pseudotsuga menziesii). At each site, one unthinned control was preserved and three thinning treatments were implemented: low complexity (LC, 300 trees ha?1), moderate complexity (MC, 200 trees ha?1), and high complexity (HC, variable densities from 100 to 300 trees ha?1). Gaps openings and leave island reserves were established in MC and HC. Results: Richness of all herbs, forest herbs, early seral herbs and shrubs, and introduced species increased in all thinning treatments, although early seral herbs and introduced species remained a small component. Only cover of early seral herbs and shrubs increased in all thinning treatments whereas forest shrub cover increased in MC and HC. In the understory, we found 284 vascular plant species. After accounting for site‐level differences, the richness of understory communities in thinned stands differed from those in control stands. Within‐treatment variability of herb and shrub richness was reduced by thinning. Matrix areas and gap openings in thinned treatments appeared to contribute to the recruitment of early seral herbs and shrubs. Conclusions: Understory vegetation richness increased 6 years after imposing treatments, with increasing stand complexity mainly because of the recruitment of early seral and forest herbs, and both low and tall shrubs. Changes in stand density did not likely lead to competitive species exclusion. The abundance of potentially invasive introduced species was much lower compared to other plant groups. Post‐thinning reductions in within‐treatment variability was caused by greater abundance of early seral herbs and shrubs in thinned stands compared with the control. Gaps and low‐density forest matrix areas created as part of spatially variably thinning had greater overall species richness. Increased overstory variability encouraged development of multiple layers of understory vegetation. 相似文献
16.
Changes in biotic and abiotic drivers of seedling species composition during forest recovery following shifting cultivation on Hainan Island,China
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Seedlings play an important role in the processes of plant community succession. We compared seedling (dbh < 1 cm) species composition and diversity over a chronosequence (18‐, 30‐, 60‐year‐old second growth and old growth forest) after shifting cultivation in a tropical lowland rain forest area on Hainan Island, China. Seedling diversity reached a maximum in the 60‐year‐old second growth forest, which is consistent with the intermediate disturbance hypothesis. With the progression of secondary succession, canopy openness (CO), soil organic matter, soil phosphorus content, and tree abundance showed a general decreasing trend; soil water content and tree basal area showed a general trend of increase, while soil pH and other nutrients reached maximum values and tree richness reached a minimum value at intermediate stages of succession. Seedling composition and diversity were significantly affected by soil water, pH, soil nutrient content, and biotic factors in the 18‐year‐old second growth forests; by soil pH, soil nutrient content, and biotic factors in the 30‐year‐old second growth forests; by CO, soil nutrient content and tree abundance in the 60‐year‐old second growth forests; and by CO, soil pH, and soil nutrient content in the old growth forests. At earlier stages of succession, the effect of the proportion of old growth forest in the surrounding landscape on seedling diversity was greater than that of land‐use history, but the importance of these drivers was reversed at later stages of succession. 相似文献
17.
G. Brunialti L. Frati M. Aleffi M. Marignani L. Rosati S. Burrascano 《Plant biosystems》2013,147(1):221-233
Abstract This study is focused on the selection of variables affecting lichen and bryophyte diversity in Mediterranean deciduous forests. Plots representing two forest types (Fagus sylvatica and Quercus cerris forests) and two forest continuity categories (old‐growth (OG) and non‐OG forests) were selected in the Cilento and Vallo di Diano National Park (Italy). The presence and the abundance of bryophytes and epiphytic lichens were recorded. Structural variables of the forests and vascular plant species richness have been used as predictors. A strong positive correspondence between the two groups of organisms was found. Higher species richness and the distribution of rare species are related to OG stands, while a qualitative (species composition) rather than a quantitative (species richness) difference between the two forest types was observed. Some species elsewhere considered as indicators of forest continuity, such as Lobaria pulmonaria, Antitrichia curtipendula, and Homalothecium sericeum, are associated with OG forests, independently from forest type, suggesting that they can be regarded as suitable indicators also in Mediterranean forests. Finally, our results suggest that old trees, high levels of basal area, a broad range of diameter classes, and high understory diversity are the main structural features affecting cryptogamic communities, while no correlation was found with the occurrence of deadwood. 相似文献
18.
Resilience of tropical dry forests – a meta‐analysis of changes in species diversity and composition during secondary succession
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Géraldine Derroire Patricia Balvanera Carolina Castellanos‐Castro Guillaume Decocq Deborah K. Kennard Edwin Lebrija‐Trejos Jorge A. Leiva Per‐Christer Odén Jennifer S. Powers Victor Rico‐Gray Mulualem Tigabu John R. Healey 《Oikos》2016,125(10):1386-1397
Assessing the recovery of species diversity and composition after major disturbance is key to understanding the resilience of tropical forests through successional processes, and its importance for biodiversity conservation. Despite the specific abiotic environment and ecological processes of tropical dry forests, secondary succession has received less attention in this biome than others and changes in species diversity and composition have never been synthesised in a systematic and quantitative review. This study aims to assess in tropical dry forests 1) the directionality of change in species richness and evenness during secondary succession, 2) the convergence of species composition towards that of old‐growth forest and 3) the importance of the previous land use, precipitation regime and water availability in influencing the direction and rate of change. We conducted meta‐analyses of the rate of change in species richness, evenness and composition indices with succession in 13 tropical dry forest chronosequences. Species richness increased with succession, showing a gradual accumulation of species, as did Shannon evenness index. The similarity in species composition of successional forests with old‐growth forests increased with succession, yet at a low rate. Tropical dry forests therefore do show resilience of species composition but it may never reach that of old‐growth forests. We found no significant differences in rates of change between different previous land uses, precipitation regimes or water availability. Our results show high resilience of tropical dry forests in term of species richness but a slow recovery of species composition. They highlight the need for further research on secondary succession in this biome and better understanding of impacts of previous land‐use and landscape‐scale patterns. Synthesis Secondary forests account for an increasing proportion of remaining tropical forest. Assessing their resilience is key to conservation of their biodiversity. Our study is the first meta‐analysis of species changes during succession focussing on tropical dry forests, a highly threatened yet understudied biome. We show a gradual species accumulation and convergence of composition towards that of old‐growth forests. While secondary tropical dry forests offer good potential for biodiversity conservation, their capacity for recovery at a sufficient rate to match threats is uncertain. Further research on this biome is needed to understand the effect of land use history and landscape processes. 相似文献
19.
ABSTRACTBackground: Quantitative effects of large-scale oil palm expansion in the Neotropics on biodiversity and carbon stocks are still poorly documented.Aims: We evaluated differences in tree species composition and richness, and above-ground carbon stocks among dominant land cover types in Pará state, Brazil.Methods: We quantified tree species composition and richness and above-ground carbon stock in stands in remnant primary rain forest, young secondary forest, oil palm plantation and pastures.Results: We sampled 5,696 trees with a DBH ≥ 2 cm, of 413 species in 68 families, of which 381 species were recorded in primary forest fragments. We found significant differences in species richness and carbon stock among the four land cover classes. Carbon stocks in remnant primary forest were typically over 190 Mg ha?1, while those in other land cover types were typically less than 60 Mg ha?1.Conclusion: Oil palm plantations have a species-poor tree community given active management; old plantations have a standing carbon stock which is comparable to that of secondary forest and far greater than that of pastures. Private forest reserves within oil palm company holdings play an important role in preserving primary forest tree diversity in human-modified landscapes in Amazonia. 相似文献
20.
It's a long way to the top: Plant species diversity in the transition from managed to old‐growth forests
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Sabina Burrascano Francesco Ripullone Liliana Bernardo Marco Borghetti Emanuela Carli Michele Colangelo Carmen Gangale Domenico Gargano Tiziana Gentilesca Giuseppe Luzzi Nicodemo Passalacqua Luca Pelle Anna Rita Rivelli Francesco Maria Sabatini Aldo Schettino Antonino Siclari Dimitar Uzunov Carlo Blasi 《植被学杂志》2018,29(1):98-109