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西天目山黄山松阔叶林的冠层干扰与动态推测 总被引：7，自引：2，他引：5
根据年龄结构和直径生长图分析研究了浙江省西天目山黄山松阔叶混交林的冠层干扰年表和发展动态。结果表明黄山松在该林地的定居发生在１８６１－１８８０年之间,黄山松定居３０－４０年后,其他阔叶树开妈在林下萌发生长,形成目前的黄山阔叶混交林,该林浆被阔叶叶树取代。 相似文献
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Erwin S. WIDODO Tikahiko NAITO Maryati MOHAMED Yoshiaki HASHIMOTO 《Entomological Science》2004,7(4):341-349
We examined the effect of selective logging and corresponding forest canopy loss on arboreal ant diversity in a tropical rainforest. Arboreal ants were collected from an unlogged forest plot and from forest plots selectively logged 14 years and 24 years earlier in Danum Valley, Sabah, Malaysia, using a canopy fogging method. Selective logging was associated with a significant decrease in canopy cover and an increase in understory vegetation density relative to unlogged forest. Our study showed that selective logging in primary forest might not dramatically decrease total species number and overall abundance of arboreal ants; however, it may influence the species composition and dominance structure of the ant community, accompanied by an increase in abundance of shrub‐layer species and trophobiotic species. In view of the results of this study, management techniques that minimize logging impact on understory vegetation structure are likely to help maintain the conservation value of logged forests for arboreal ants. Our results also suggest that accurate assessment of the impacts on biodiversity should not be based only on measurement of species number and overall abundance, but also on analysis of species composition and community structure. 相似文献
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Kathrin Affeld Susan Worner Raphael K. Didham Jon Sullivan Rosa Henderson Jagoba Malumbres Olarte 《New Zealand journal of zoology.》2013,40(2):177-202
Abstract The range of microhabitats and microclimatic conditions provided by epiphytes has been linked to the high diversity of invertebrates in many forest canopies worldwide, but comparably little is known about the invertebrate fauna in this habitat in New Zealand. This study compiled an inventory of the invertebrate fauna of epiphyte mats in the canopy of northern rata (Myrtaceae: Metrosideros robusta A. Cunn.) at two study sites on the West Coast of the South Island. A total of 242 069 invertebrate specimens was collected over one year, representing 4 phyla, 9 classes and more than 160 families, 225 genera and 446 species. At least 10 new species and 3 new genera were identified, while 5 species were recorded outside their known geographical range. Epiphyte mats provided habitat for an invertebrate fauna, highly diverse and abundant both taxonomically and functionally, dominated in terms of abundance by Acari, Collembola and Hymenoptera (largely ants), and in terms of feeding guilds by epiphyte grazers and ants. As the first inventory of this taxonomic depth and breadth compiled for New Zealand forest epiphyte habitats, this study provides important baseline data for the conservation of biodiversity in New Zealand's indigenous forests. 相似文献
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Robin Pouteau Juliette Picard Charles Doumenge Terry Brncic Jean-François Gillet Jean-Louis Doucet Sylvie Gourlet-Fleury Victor Kimpouni Jean-Joël Loumeto Raphaël Pélissier Maxime Réjou-Méchain 《American journal of botany》2024,111(4):e16320
Marantaceae forests are tropical rainforests characterized by a continuous understory layer of perennial giant herbs and a near absence of tree regeneration. Although widespread in West-Central Africa, Marantaceae forests have rarely been considered in the international literature. Yet, they pose key challenges and opportunities for theoretical ecology that transcend the borders of the continent. Specifically, we ask in this review whether open Marantaceae forests and dense closed-canopy forests can be considered as one of the few documented examples of alternative stable states in tropical forests. First, we introduce the different ecological factors that have been posited to drive Marantaceae forests (climate, soil, historical and recent anthropogenic pressures, herbivores) and develop the different hypotheses that have been suggested to explain how Marantaceae forests establish in relation with other vegetation types (understory invasion, early succession after disturbance, and intermediate successional stage). Then, we review the underlying ecological mechanisms that can explain the stability of Marantaceae forests in the long term (tree recruitment inhibition, promotion of and resilience to fire, adaptive reproduction, maintenance by megaherbivores). Although some uncertainties remain and call for further empirical and theoretical research, we found converging evidence that Marantaceae forests are associated with an ecological succession that has been deflected or arrested. If verified, Marantaceae forests may provide a useful model to understand critical transitions in forest ecosystems, which is of particular relevance to achieve sustainable forest management and mitigate global climate change. 相似文献
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We assessed the effectiveness of repopulating the inner canopy and middle canopy of oak trees with seeds and seedlings of the epiphytic bromeliad Tillandsia eizii. Canopy germination was 4.7 percent, considerably lower than in vitro (92%). Of the tree-germinated seedlings, only 1.5 percent survived 6 mo. In contrast, 9.3 percent of transplanted laboratory seedlings survived 15 mo. To repopulate trees, we recommend transplanting laboratory-grown seedlings, as large as practically possible, to branches in the middle canopy. 相似文献
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石松类及蕨类植物在高等植物中处于比较特殊的进化与系统发育地位, 同时具有孢子植物(孢子)与种子植物(维管束)的双重特征。附生蕨类植物是蕨类植物中占据独特生境的一个大类群, 其生活史策略及进化历史与其附生生长的森林生态系统紧密相关。大部分附生蕨类植物的克隆生长习性及克隆生活史性状在其生态适应中具有重要作用, 但这方面未引起广泛关注。本文主要综述了中国山地森林中附生蕨类植物的根状茎克隆生长、克隆性与生态适应性、不同克隆生长方式与进化等方面, 并展望了蕨类植物克隆性在森林生态系统过程与功能中的作用, 以及今后如何将蕨类植物生态学研究与气候变化、植被恢复、土地利用变化等全球变化的主流方向进行结合。 相似文献
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云南亚高山云冷杉林林窗的研究 总被引：23，自引：3，他引：23
研究了云南碧塔海两块亚高山云冷杉（Ｐｉｃｅａ－Ａｂｉｅｓ）林内中小尺度林窗的干扰体系,结果表明：林窗和扩展林窗分别占林地面积的１９％和４１％,平均面积为４４ｍ２和１３９ｍ２,林窗的形成频率为０．００５～０．００７／ｙ。估计平均林窗周期为１６７年。大多数林窗（占８７％）的制造林窗树木（ｇａｐ－ｍａｋｅｒ,简记为ＧＭ）为１个以上,平均每个林窗的ＧＭ为２．９个,同一林窗内的ＧＭ常常死于不同的时间。在所有调查的ＧＭ中,折断占６０％,而根拔和直立死亡分别为２８％和１２％ 相似文献
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The population structure and dynamics of Castanopsis cuspidata var. sieboldii were studied to evaluate vegetative and sapling regeneration in an old-growth, evergreen broad-leaved forest exposed to low-severity typhoon disturbances by annual typhoons on the Tsushima Islands in Japan. The density of individuals 5cm d.b.h. was 38.0ha–1 in 1990; 7.9% were multiple-stemmed individuals. Over the 7-year study period (1990–1997), the number of individuals decreased, although the number of stems increased. Over 30% of apparently dead individuals were reconstituted by sprouting stems. Compared with sprout regeneration, sapling regeneration rarely occurred and was only observed in canopy gaps. Most individuals had at least one sprout shoot (H 30cm, d.b.h. <5cm), and the number and size of sprout shoots increased as the size of the individuals increased. During the study period, larger individuals with stem breakage tended to produce sprout stems. The density of saplings was 1074ha–1 and they were more abundant in canopy gaps than under closed canopies, but large saplings were very rare even in canopy gaps. The population of C.cuspidata var. sieboldii consisted primarily of single-stemmed individuals with a few multiple-stemmed individuals providing a sprout bank. Larger individuals responded to the low severity typhoon disturbances and formed sprout stems. Although many saplings were observed, regeneration occurred more often by sprout formation than by growth of saplings. Thus, sprout regeneration is an important mode of regeneration, which allows this pioneer-like species to maintain its population in this forest. 相似文献
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Sarah Boon 《Ecohydrology》2012,5(3):279-285
Mountain pine beetle (MPB) infestation and salvage logging create a post‐disturbance landscape composed of a patchwork of alive, dead, and clearcut forest stands. Subsequent impacts on runoff generation in snowmelt‐dominated hydrological regimes are largely a function of the proportion of landscape covered by each stand type, but basic information on snow accumulation variations between stand types following beetle infestation is lacking. This study examines snow accumulation in the post‐disturbance landscape of northern interior British Columbia, Canada, to quantify the effects of MPB‐related forest cover change. Field measurements collected in a live and a dead coniferous plot during the 2007 and 2008 winters are compared with those collected in a clearcut (canopy‐free control) to identify inter‐plot differences in snow depth, density, and water equivalent. Interannual variability in snow density and water equivalent is significantly affected by interannual variability in meteorological conditions. In high snow years, the dead and alive plots behave similarly due to the ability of large snowfalls to exceed the interception capacity of the canopy. In low‐to‐average snow years, however, distinct differences in snow accumulation between the dead and alive plots are observed. These are largely due to the canopy structure in the dead plot, which differs significantly from that in the healthy plot largely due to defoliation (needle drop) and the loss of fine branches and stems following beetle infestation. Research results provide key process information for modelling studies examining the effects of these changes on runoff generation at the watershed scale. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Xiaona Shao Calum Brown Samantha J. Worthy Lu Liu Min Cao Qiaoming Li Luxiang Lin Nathan G. Swenson 《Ecology letters》2018,21(8):1174-1181
Intra‐specific negative density dependence promotes species coexistence by regulating population sizes. Patterns consistent with such density dependence are frequently reported in diverse tropical tree communities. Empirical evidence demonstrating whether intra‐specific variation is related to these patterns, however, is lacking. The present study addresses this important knowledge gap by genotyping all individuals of a tropical tree in a long‐term forest dynamics plot in tropical China. We show that related individuals are often spatially clustered, but having closely related neighbours reduces the growth performance of focal trees. We infer from the evidence that dispersal limitation and negative density dependence are operating simultaneously to impact the spatial distributions of genotypes in a natural population. Furthermore, dispersal limitation decreases local intra‐specific genetic diversity and increases negative density dependence thereby promoting niche differences and species coexistence as predicted by theory. 相似文献
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附生维管植物对维持森林生态系统的生物多样性、碳储量、生态水文和养分通量有重要贡献。评估附生植物的多样性格局可以为其群落构建机制以及全球变化背景下附生植物的保护和资源利用提供依据。本文以哀牢山中山湿性常绿阔叶林1.44 ha塔吊样地中的附生维管植物为研究对象, 综合分析了6种优势乔木宿主植株上附生维管植物的物种丰富度(S)、系统发育多样性(PD)、系统发育结构及其与宿主胸径、树高和物种的相关性。结果表明: 哀牢山中山湿性常绿阔叶林311株优势乔木上共调查到26科44属62种附生维管植物。附生植物物种丰富度和系统发育多样性与宿主胸径和树高均呈极显著正相关(P < 0.001)。标准化的系统发育多样性(SES.PD)与附生植物物种丰富度无显著相关关系, 随宿主胸径的增加而显著增加(P < 0.05), 随宿主树高的增加而显著减小(P < 0.05)。折柄茶(Stewartia pteropetiolata)上附生植物的物种丰富度与PD极显著低于其他宿主物种(P < 0.001), 但6种宿主物种上附生植物的SES.PD无显著差异(P > 0.05)。变色锥(Castanopsis wattii)和多花含笑(Michelia floribunda)上的附生植物系统发育结构呈发散状态, 木果柯(Lithocarpus xylocarpus)和折柄茶上的附生植物系统发育结构呈聚集状态, 其余宿主上的附生植物系统发育结构不明显。综上所述, 宿主特征包括宿主大小和物种的差异是维持附生维管植物多样性格局的关键, 这一结果可为今后从多维度、多角度解析附生维管植物多样性的格局及其维持机制奠定坚实基础。 相似文献
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The presence of charcoal in the soils and fire scars on 8.2 percent of tree stems strongly suggest that one of the best studied Amazonian research localities (the Ilha de Maracá in Roraima, Brazil) has burned. The patterns and images of fire scars that we present here could help researchers explore the burn history of other tropical forests, which has important implications for interpreting their present-day ecology. 相似文献
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Natural forest growth and expansion are important carbon sequestration processes globally. Climate change is likely to increase forest growth in some regions via CO2 fertilization, increased temperatures, and altered precipitation; however, altered disturbance regimes and climate stress (e.g. drought) will act to reduce carbon stocks in forests as well. Observations of asynchrony in forest change is useful in determining current trends in forest carbon stocks, both in terms of forest density (e.g. Mg ha?1) and spatially (extent and location). Monitoring change in natural (unmanaged) areas is particularly useful, as while afforestation and recovery from historic land use are currently large carbon sinks, the long‐term viability of those sinks depends on climate change and disturbance dynamics at their particular location. We utilize a large, unmanaged biome (>135 000 km2) which spans a broad latitudinal gradient to explore how variation in location affects forest density and spatial patterning: the forests of the North American temperate rainforests in Alaska, which store >2.8 Pg C in biomass and soil, equivalent to >8% of the C in contiguous US forests. We demonstrate that the regional biome is shifting; gains exceed losses and are located in different spatio‐topographic contexts. Forest gains are concentrated on northerly aspects, lower elevations, and higher latitudes, especially in sheltered areas, whereas loss is skewed toward southerly aspects and lower latitudes. Repeat plot‐scale biomass data (n = 759) indicate that within‐forest biomass gains outpace losses (live trees >12.7 cm diameter, 986 Gg yr?1) on gentler slopes and in higher latitudes. This work demonstrates that while temperate rainforest dynamics occur at fine spatial scales (<1000 m2), the net result of thousands of individual events is regionally patterned change. Correlations between the disturbance/establishment imbalance and biomass accumulation suggest the potential for relatively rapid biome shifts and biomass changes. 相似文献
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Regeneration patterns and persistence of the fog-dependent Fray Jorge forest in semiarid Chile during the past two centuries 总被引：1，自引：0，他引：1
ALVARO G. GUTIÉRREZ † OLGA BARBOSA‡§ DUNCAN A. CHRISTIE¶ EK DEL-VAL&#; HOLLY A. EWING CLIVE G. JONES†† PABLO A. MARQUET†§ KATHLEEN C. WEATHERS†† JUAN J. ARMESTO†§†† 《Global Change Biology》2008,14(1):161-176
The persistence of rainforest patches at Fray Jorge National Park (FJNP) in semiarid Chile (30°40′S), a region receiving approximately 147 mm of annual rainfall, has been a source of concern among forest managers. These forests are likely dependent on water inputs from oceanic fog and their persistence seems uncertain in the face of climate change. Here, we assessed tree radial growth and establishment during the last two centuries and their relation to trends in climate and canopy disturbance. Such evaluation is critical to understanding the dynamics of these semiarid ecosystems in response to climate change. We analyzed forest structure of six forest patches (0.2–22 ha) in FJNP based on sampling within 0.1 ha permanent plots. For the main canopy species, the endemic Aextoxicon punctatum (Aextoxicaceae), we used tree‐ring analysis to assess establishment periods, tree ages, growing trends and their relation to El Niño Southern Oscillation (ENSO), rainfall, and disturbance. The population dynamics of A. punctatum can be described by a continuous regeneration mode. Regeneration of A. punctatum was sensitive to different canopy structures. Growth release patterns suggest the absence of large scale human impact. Radial growth and establishment of A. punctatum were weakly correlated with rainfall and ENSO. If water limits forests patch persistence, patches are likely dependent on the combination of fog and rain water inputs. Forest patches have regenerated continuously for at least 250 years, despite large fluctuations in rainfall driven by ENSO and a regional decline in rainfall during the last century. Because of the positive influence on fog interception, forest structure should be preserved under any future climate scenario. Future research in FJNP should prioritize quantifying the long‐term trends of fog water deposition on forests patches. Fog modeling is crucial for understanding the interplay among physical drivers of water inputs under climate change. 相似文献
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Plant–plant interactions change through succession from facilitative to competitive. At early stages of succession, early‐colonizing plants can increase the survival and reproductive output of other plants by ameliorating disturbance and stressful conditions. At later stages of succession, plant interactions are more competitive as plants put more energy toward growth and reproduction. In northern temperate rainforests, gap dynamics result in tree falls that facilitate tree regeneration (nurse logs) and bryophyte succession. How bryophyte‐tree seedling interactions vary through log succession remains unclear. We examined the relationships of tree seedlings, bryophyte community composition, bryophyte depth, and percent canopy cover in 166 1.0 m2 plots on nurse logs and the forest floor in the Hoh rainforest in Washington, USA, to test the hypothesis that bryophyte‐tree seedling interactions change from facilitative to competitive as the log decays. Tree seedling density was highest on young logs with early‐colonizing bryophyte species (e.g., Rhizomnium glabrescens) and lowest on decayed logs with Hylocomium splendens, a long‐lived moss that reaches depths >20 cm. As a result, bryophyte depth increased with nurse log decay and was negatively associated with tree seedling density. Tree seedling density was 4.6× higher on nurse logs than on the forest floor, which was likely due to competitive exclusion by forest floor plants, such as H. splendens. Nurse logs had 17 species of bryophytes while the forest floor had six, indicating that nurse logs contribute to maintaining bryophyte diversity. Nurse logs enable both tree seedlings and smaller bryophyte species to avoid competition with forest floor plants, including the dominant bryophyte, H. splendens. H. splendens is likely a widespread driver of plant community structure given its dominance in northern temperate forests. Our findings indicate that plant–plant interactions shift with succession on nurse logs from facilitative to competitive and, thus, influence forest community structure and dynamics. 相似文献