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1.
An abundance index of an eastern Quebec population of North American porcupines (Erethizon dorsatum) has cycled with superimposed periodicities of 11 and 22 years from 1868 to 2000. This cycle closely followed 11- and 22-year cycles in solar irradiance and local weather (e.g., winter precipitation and spring temperature), generating the hypothesis that solar activity may affect porcupine abundance through effects on local weather. We investigated the mechanisms linking porcupine abundance to local weather conditions using a 6-year study (2000–2005) involving individual mark-recapture, radio tracking, seasonal survival analyses and identification of mortality causes. Summer (May–August) survival was high and constant over the study period, whereas winter (August–May) survival was lower and varied during the duration of our study. Variations in local winter precipitation explained 89% of the variation in winter survival. Porcupine predation rates appeared strongly related to snow conditions; 95% of depredated porcupines were killed when snow was covering the ground, and predation rates were higher in years with increased winter precipitation. Our data thus support the hypothesis that changes in predation rates under different snow conditions were the mechanism relating climate to porcupine population dynamics, via modifications of the local predator–prey interactions and impacts on porcupine winter survival. Our study adds to the growing body of evidence supporting an effect of climate on predator–prey processes. Also, it identifies one possible mechanism involved in the relationship between solar irradiance and porcupine population cycles observed at this study site over a 130-year period.  相似文献   

2.
李潇  吴克宁  冯喆  王颖涵 《生态学报》2022,42(23):9627-9635
土地利用变化影响陆地系统碳循环过程。在实现碳中和目标的背景下,分析区域碳平衡,优化土地利用结构具有现实意义。以河南省为例,以1 km网格为单元,应用InVEST碳固存模块、IPCC碳排放核算、人口密度法等方法,研究1995、2005、2015年区域碳平衡的时空变化。结果表明,研究区固碳服务的供需量与土地利用类型密切相关。固碳服务的供需在空间存在错配关系,即需求高的地区通常具有较低的供给。研究时段内,研究区的总碳固量逐年下降,总碳排放量逐年增加,研究区碳平衡表现为整体向好,局部恶化的情况。在碳平衡分析的基础上提出了空间优化利用建议,可为未来国土空间规划碳平衡目标的实现提供参考。  相似文献   

3.
Changes in the terrestrial carbon cycle may ameliorate or exacerbate future climatic warming. Research on this topic has focused almost exclusively on abiotic drivers, whereas biotic factors, including trophic interactions, have received comparatively little attention. We quantified the singular and interactive effects of herbivore exclusion and simulated warming on ecosystem CO2 exchange over two consecutive growing seasons in West Greenland. Exclusion of caribou and muskoxen over the past 8 years has led to dramatic increases in shrub cover, leaf area, ecosystem photosynthesis, and a nearly threefold increase in net C uptake. These responses were accentuated by warming, but only in the absence of herbivores. Carbon cycle responses to herbivore exclusion alone and combined with warming were driven by changes in gross ecosystem photosynthesis, as limited differences in ecosystem respiration were observed. Our results show that large herbivores can be of critical importance as mediators of arctic ecosystem responses to climate change.  相似文献   

4.
Temporal coherence or spatial synchrony refers to the tendency of population, community or ecosystem dynamics to behave similarly among locations through time as a result of spatially‐correlated environmental stochasticity (Moran effect), dispersal or trophic interactions. While terrestrial studies have treated synchrony mainly as a population‐level concept, the majority of freshwater studies have focused on community‐level patterns, particularly in lake planktonic communities. We used spatially and temporally hierarchical data on benthic stream invertebrates across six years, with three seasonal samples a year, in 11 boreal streams to assess temporal coherence at three spatial extents: 1) among regions (watersheds), 2) among streams within a region, and 3) among riffles within a stream, using the average of correlation coefficients for stream/riffle pairs across years. Our results revealed the primacy of strongly synchronized climatic factors (precipitation, air temperature) in inducing temporal coherence of macroinvertebrate assemblages across geographically distinct sites (i.e. Moran effect). Coherence tended to decrease with increasing spatial extent, but positive coherence was detected for most biological variables even at the largest extent (about 350 km). The generally high level of coherence reflected the strong seasonality of boreal freshwater communities. A hydrologically exceptional year enhanced the synchrony of biological variables, particularly total macroinvertebrate abundance. Regionally low precipitation in that year led to a substantial decrease in benthic densities across a broad spatial extent, followed by a rapid post‐drought recovery. Coherence at the among‐riffle (within‐stream) extent was lower than expected, implying that local‐scale habitat filters determine community dynamics at smaller spatial extents. Thus, temporal coherence of stream benthic communities appears to be controlled by partly different processes at different spatial scales.  相似文献   

5.
Understanding terrestrial carbon metabolism is critical because terrestrial ecosystems play a major role in the global carbon cycle. Furthermore, humans have severely disrupted the carbon cycle in ways that will alter the climate system and directly affect terrestrial metabolism. Changes in terrestrial metabolism may well be as important an indicator of global change as the changing temperature signal. Improving our understanding of the carbon cycle at various spatial and temporal scales will require the integration of multiple, complementary and independent methods that are used by different research communities. Tools such as air sampling networks, inverse numerical methods, and satellite data (top-down approaches) allow us to study the strength and location of the global- and continental-scale carbon sources and sinks. Bottom-up studies provide estimates of carbon fluxes at finer spatial scales and examine the mechanisms that control fluxes at the ecosystem, landscape, and regional scales. Bottom-up approaches include comparative and process studies (for example, ecosystem manipulative experiments) that provide the necessary mechanistic information to develop and validate terrestrial biospheric models. An iteration and reiteration of top-down and bottom-up approaches will be necessary to help constrain measurements at various scales. We propose a major international effort to coordinate and lead research programs of global scope of the carbon cycle. Received 7 May 1999; accepted 28 September 1999.  相似文献   

6.
干旱对陆地生态系统生产力的影响   总被引:7,自引:2,他引:5       下载免费PDF全文
该文综述了干旱对陆地生态系统生产力的影响,分析了其影响机制,并总结了植被对干旱的响应与适应及其机理机制。干旱通过抑制光合作用来降低陆地生态系统总初级生产力,干旱还可以降低生态系统的自养呼吸和异养呼吸。同时干旱还可以通过影响其它干扰形式来间接影响陆地生态系统生产力,如增加火干扰的发生频率和强度,增加植物的死亡率,增加病虫害的发生等。在生态系统水平上干旱可以降低碳固定,减弱碳汇功能,甚至把生态系统从碳汇改变成碳源。目前生态系统水平上的干旱影响研究主要通过两种方法实现,一种是模型模拟,另一种就是大型模拟实验。作为陆地生态系统生产力的实现者,在干旱胁迫条件下,植物也会采取积极的适应策略以减弱干旱对生态系统生产力的影响,其适应策略主要分以下3种:在一些周期性发生干旱的地区,植物会调整生长期以避开干旱或通过休眠来减弱干旱所造成的伤害;还有一些植物会通过调节体内的代谢过程,改变一些生理特性来抵御干旱;而长期生活在干旱条件下的植物则通过进化来改变了自身的生理生化代谢过程,形成耐旱机制。目前,植物对干旱响应的分子学机制,以及生态系统水平上对干旱的响应和适应仍然是薄弱的领域,也必然成为未来研究的重点。  相似文献   

7.
 植被净初级生产力及其对气候变化的响应研究是全球变化的核心内容之一。在利用内蒙古典型草原连续13年的地上生物量资料对基于遥感信息的生态系统碳循环过程CASA(Carnegie-Ames-Stanford Approach)模型验证的基础上, 分析了内蒙古典型草原1982~2002年植被净初级生产力(Net primary productivity, NPP)的时间变异及其影响因子。结果表明: 1) 1982~2002年21年间内蒙古典型草原的平均年NPP为290.23 g C·m–2·a–1, 变化范围为 145.80~502.84 g C·m–2·a–1; 2)内蒙古典型草原NPP呈增加趋势, 但没有达到显著性水平, 其中1982~1999年的18年间NPP呈现非常显著的增加趋势(p<0.01), NPP增加的直接原因是由于生长旺季生长本身增强所致; 3)内蒙古典型草原NPP与年降水量呈极显著的相关关系, 年降水量显著影响NPP的变异, 而NPP与年均温无显著相关关系。  相似文献   

8.
Genetic differentiation in space can be detected at various scales. First, habitat fragmentation can produce a mosaic genetic structure. Second, life history aspects of a species such as dispersion, mating system, and pollination can generate a genetic structure at a finer level. The interplay of these levels has rarely been studied together. In order to assess the effects of forest fragmentation we analyzed the genetic structure at two spatial scales of the terrestrial orchid Cyclopogon luteoalbus, which lives in patches inside forest fragments in a cloud forest of eastern Mexico. We hypothesized high differentiation between forest fragments and strong spatial genetic structure within fragments under this scenario of strong fragmentation and restricted dispersal patterns. Using 11 allozymic loci we found high genetic diversity at fragment level with moderate differentiation among fragments, and at patch level, strong and variable spatial genetic structure among life cycle stages with high inbreeding coefficients. We also found bottlenecks indicating recent population size reductions. While both inbreeding and restricted seed dispersal may explain the strong spatial genetic structure at patch level, reduction in population size may explain the genetic structure at fragment level. However, the levels of genetic diversity indicate that some between-fragment gene flow has occurred. Bottlenecks and high inbreeding at patch level may result in local extinctions, but as long as an important number of fragments remain, patch recolonization through immigration is possible in C.?luteoalbus.  相似文献   

9.
火干扰与生态系统的碳循环   总被引:18,自引:0,他引:18  
吕爱锋  田汉勤  刘永强 《生态学报》2005,25(10):2734-2743
火干扰是陆地生态系统碳循环的重要影响因子。它改变着整个系统的碳循环过程与碳分布格局。正确评估火干扰在碳循环过程中的作用,对推进全球碳循环研究有着重要的意义。从4个方面系统的回顾了火干扰对碳循环的影响过程及其研究方法:(1)火烧过程中含碳痕量气体排放的估算;(2)火烧迹地恢复过程中净第一性生产力(NPP)与土壤呼吸的变化;(3)火干扰对生态系统碳源/汇的影响;(4)模型方法在火干扰与生态系统碳循环研究中的应用。目前火灾碳排量的估算方法业已成熟,但进行更精确的估算必须基于对受干扰生态系统的性质以及火势的时空变异性质的准确理解;相比之下,对于间接的、更为重要的影响,即对火烧迹地恢复过程中碳循环变化的研究则显不足。由于数据缺乏,现有研究大多限于对碳循环某一方面的观测与定量描述,缺乏全面的机理性分析。对此,实地观测、模型模拟与遥感观测的跨尺度集成将成为未来火干扰研究的一个主要方向。  相似文献   

10.
刘坤  张慧  孔令辉  乔亚军  胡梦甜 《生态学报》2023,43(10):4294-4307
“碳中和”是我国作出的一项重大的国家战略决策,陆地生态系统碳汇作为碳增汇的重要组成部分,在碳中和目标实现的过程中发挥着重要的作用。但当前基于不同观测数据和方法的陆地碳汇计算仍有很大的不确定性,为了全面了解陆地生态系统碳汇分布特征,提高陆地生态系统碳汇评估的准确性,梳理了近年来关于陆地生态系统碳汇评估的国内外研究进展,从“自下而上”和“自上而下”两类途径阐述了陆地生态系统碳汇评估的主要方法(样地清查法、涡度相关法、模型模拟法和碳同化反演法)的主要原理和特征,优势和缺陷,及在不同尺度碳汇研究中的应用,并从土地利用/覆盖变化、气候因素(大气CO2浓度、氮沉降)、环境因素(太阳辐射、温度、降水)等因素阐述了陆地系统碳汇主要驱动因子;分析了我国陆地生态系统碳汇的主要特征及时空变化趋势,并从人类活动(生态工程)和环境因素阐述了中国陆地生态系统碳汇的驱动因素;最后,展望了新的监测手段和评估方法在提升陆地生态系统碳汇评估精度中的作用,从而更好的服务于我国“碳中和”的长远目标。  相似文献   

11.
The past two decades have seen great progress in understanding the mechanisms of ecosystem stability in local ecological systems. There is, however, an urgent need to extend existing knowledge to larger spatial scales to match the scale of management and conservation. Here, we develop a general theoretical framework to study the stability and variability of ecosystems at multiple scales. Analogously to the partitioning of biodiversity, we propose the concepts of alpha, beta and gamma variability. Gamma variability at regional (metacommunity) scale can be partitioned into local alpha variability and spatial beta variability, either multiplicatively or additively. On average, variability decreases from local to regional scales, which creates a negative variability–area relationship. Our partitioning framework suggests that mechanisms of regional ecosystem stability can be understood by investigating the influence of ecological factors on alpha and beta variability. Diversity can provide insurance effects at the various levels of variability, thus generating alpha, beta and gamma diversity–stability relationships. As a consequence, the loss of biodiversity and habitat impairs ecosystem stability at the regional scale. Overall, our framework enables a synthetic understanding of ecosystem stability at multiple scales and has practical implications for landscape management.  相似文献   

12.
Precipitation from the previous August to the current June over the last 232 years in Liancheng, China, was reconstructed by a transfer function based on the correlation between tree-ring widths and local meteorological data. The explained variance was 45.3 %, and fluctuations on both annual and decadal scales were captured. Wet periods with precipitation above the 232-year mean occurred from 1777 to 1785, 1802 to 1818, 1844 to 1861, 1889 to 1922 and 1939 to 1960. Dry periods (precipitation below the mean) occurred from 1786 to 1801, 1819 to 1843, 1862 to 1888 and 1923 to 1938. The reconstruction compares well with a tree-ring-based precipitation reconstruction at Mt. Xinglong; both of them showed the well-known severe drought in the late 1920s. The rainfall series also shows highly synchronous decreasing trends since the 1940s, suggesting that precipitation related to the East Asian summer monsoon at these two sites has decreased by large spatial and temporal (decadal) scales. Power spectrum analysis of the reconstruction showed remarkable 21.82-, 3.48-, 3.12-, 3.08- and 2.31-year cycles for the past 232 years; the 22-year cycle corresponds to the solar cycle and is expressed widely in tree ring/precipitation reconstructions on the China Loess Plateau. This may suggest a solar influence on the precipitation variations on the Loess Plateau, although the mechanisms are not well understood.  相似文献   

13.
顾峰雪  黄玫  张远东  李洁  郭瑞  严昌荣 《生态学报》2017,37(8):2770-2778
由于人类活动影响,通过沉降和施肥方式进入生态系统的活性氮显著增加,其对土壤有机碳库产生重要影响。氮素利用效率(NUE)作为深入理解陆地生态系统碳氮耦合关系的重要参数,对NUE时空规律的研究不仅可以评估目前氮输入对陆地生态系统碳汇增加的贡献,同时也有助于预测未来氮输入情况下陆地生态系统的碳平衡。利用生态系统过程模型——CEVSA2模型的模拟结果,分析了东北地区氮输入情况下,土壤碳的氮素利用效率(SNUE)的时空变化规律及其影响因素,结果表明:(1)1961—2010年,氮输入的显著增加促进了土壤碳的蓄积,但SNUE显著下降;(2)森林的平均SNUE最高,农田最低;灌丛的下降速率最大,森林的SNUE变化趋势最不显著;(3)三江平原和长白山地区以及大小兴安岭的部分地区SNUE最大,其次是辽河平原、松嫩平原地区;内蒙古高原、呼伦贝尔高原地区以及大、小兴安岭的部分地区SNUE出现负值,说明在这些地区,外援氮输入抑制了土壤碳的蓄积;(4)氮输入的空间分异和不同生态系统响应氮输入的差异共同决定了SNUE及其变化的空间格局。该研究结果可为进一步分析不同区域氮促汇潜力和预测未来氮输入情景下的区域碳平衡提供参考。  相似文献   

14.
陆地生态系统是全球第二大碳库,其碳收支一直是气候变化研究的热点领域,而研究二氧化碳(CO2)施肥效应又是全球变化碳循环领域较为关注的前沿部分。CO2与生态系统关系复杂,当前仍无法厘清CO2对陆地生态系统碳循环的影响作用。基于太阳辐射数据、气温数据及归一化植被指数数据等,利用光能利用率遥感模型,模拟2019年甘南地区的碳循环,选取三个指标,即GPP (陆地生态系统总初级生产力)、NPP (净初级生产力)和NEP (净生态系统生产力)来分析甘南地区植被固碳的时空变化特征及CO2施肥效应。结果表明:(1)甘南地区2019年植被固碳总量约为2611 tC。甘南地区生态系统GPP、NPP和NEP季节性特征明显,其值均在夏季达到最高;而在空间上,GPP、NPP表现为东高西低的特征,NEP呈现出北高南低的分布特征。(2) CO2对GPP、NPP存在正向的施肥效应,分别增加了14.4%和14.3%;而对NEP具有负向反馈效应,使其减少了0.3%,并且CO2对NEP的影响整体也表现为北高南低的特征。研究揭示出:虽然CO2在提升GPP和NPP时,正向的施肥效应明显,但是对甘南地区的NEP,即固碳量来说,CO2的影响却很有限。因此在研究CO2施肥效应时不应一概而论,生态地理环境对其的影响不可忽视。研究可以为揭示陆地生态系统碳循环的动态机制提供一定的理论依据。  相似文献   

15.
黄豪奔  徐海量  林涛  夏国柱 《生态学报》2022,42(7):2798-2809
气候变化是干旱区植被变化的重要驱动因素,探究干旱区气候与植被关系的时空变化,有助于理解生态系统演化特征。基于MODIS-NDVI与CRU数据集中气候数据(降水、平均气温、最高气温、最低气温、水汽压及潜在蒸散),采用Sen+Mann-kendall、Hurst指数及相关分析法,在不同时间尺度评价了阿勒泰地区NDVI的时空变化特征及其对气候变化的响应。结果表明:(1)在年尺度上,植被NDVI整体呈上升趋势,但存在弱反持续特征。区域内植被退化现象严重(12.11%),植被改善区域与退化区域呈破碎化分布。(2)月尺度与季尺度上,NDVI与降水、气温、极端气温、水汽压和潜在蒸散呈正相关,其中降水因素在季尺度上的相关性高于月尺度。(3)不同土地利用方式下NDVI与气候因子的滞后效应表现为短期正效应与长期负效应。  相似文献   

16.
喀斯特石漠化已成为制约我国西南地区社会经济可持续发展最严重的生态地质环境问题,其恢复重建已成为我国社会经济建设中一项重要内容。土壤有机碳作为土壤质量评价的重要指标,可以综合反映土地生产力、环境健康功能,另一方面土壤有机碳也间接影响了陆地生物碳库,是陆地生态系统碳平衡的主要因子,它的转化和积累变化直接影响全球碳循环动态,已成为生态科学领域研究的热点之一。系统的总结了西南喀斯特石漠化地区不同土地覆被/土地利用、不同等级石漠化环境土壤有机碳的空间和季节分布特征。结合前人研究成果,进一步分析了影响喀斯特石漠化地区土壤有机碳分布的自然(气候、地形与土壤性质、植被等)和人为(土地覆被/土地利用变化、农业管理措施等)各因素,并提出增加喀斯特石漠化地区土壤有机碳含量的对策。研究结果为喀斯特石漠化退化生态系统恢复重建、石漠化地区土壤综合利用、增加碳截存应对全球碳循环减源增汇等提供了重要的科学参考。  相似文献   

17.
The Lund–Potsdam–Jena Dynamic Global Vegetation Model (LPJ) combines process‐based, large‐scale representations of terrestrial vegetation dynamics and land‐atmosphere carbon and water exchanges in a modular framework. Features include feedback through canopy conductance between photosynthesis and transpiration and interactive coupling between these ‘fast’ processes and other ecosystem processes including resource competition, tissue turnover, population dynamics, soil organic matter and litter dynamics and fire disturbance. Ten plants functional types (PFTs) are differentiated by physiological, morphological, phenological, bioclimatic and fire‐response attributes. Resource competition and differential responses to fire between PFTs influence their relative fractional cover from year to year. Photosynthesis, evapotranspiration and soil water dynamics are modelled on a daily time step, while vegetation structure and PFT population densities are updated annually. Simulations have been made over the industrial period both for specific sites where field measurements were available for model evaluation, and globally on a 0.5°° × 0.5°° grid. Modelled vegetation patterns are consistent with observations, including remotely sensed vegetation structure and phenology. Seasonal cycles of net ecosystem exchange and soil moisture compare well with local measurements. Global carbon exchange fields used as input to an atmospheric tracer transport model (TM2) provided a good fit to observed seasonal cycles of CO2 concentration at all latitudes. Simulated inter‐annual variability of the global terrestrial carbon balance is in phase with and comparable in amplitude to observed variability in the growth rate of atmospheric CO2. Global terrestrial carbon and water cycle parameters (pool sizes and fluxes) lie within their accepted ranges. The model is being used to study past, present and future terrestrial ecosystem dynamics, biochemical and biophysical interactions between ecosystems and the atmosphere, and as a component of coupled Earth system models.  相似文献   

18.
The terrestrial forest ecosystems in the northern high latitude region have been experiencing significant warming rates over several decades. These forests are considered crucial to the climate system and global carbon cycle and are particularly vulnerable to climate change. To obtain an improved estimate of the response of vegetation activity, e.g., forest greenness and tree growth, to climate change, we investigated spatiotemporal variations in two independent data sets containing the dendroecological information for this region over the past 30 years. These indices are the normalized difference vegetation index (NDVI3g) and the tree‐ring width index (RWI), both of which showed significant spatial variability in past trends and responses to climate changes. These trends and responses to climate change differed significantly in the ecosystems of the circumarctic (latitude higher than 67°N) and the circumboreal forests (latitude higher and lower than 50°N and 67°N, respectively), but the way in which they differed was relatively similar in the NDVI3g and the RWI. In the circumarctic ecosystem, the climate variables of the current summer were the main climatic drivers for the positive response to the increase in temperatures showed by both the NDVI3g and the RWI indices. On the other hand, in the circumboreal forest ecosystem, the climate variables of the previous year (from summer to winter) were also important climatic drivers for both the NDVI3g and the RWI. Importantly, both indices showed that the temperatures in the previous year negatively affected the ecosystem. Although such negative responses to warming did not necessarily lead to a past negative linear trend in the NDVI3g and the RWI over the past 30 years, future climate warming could potentially cause severe reduction in forest greenness and tree growth in the circumboreal forest ecosystem.  相似文献   

19.
近144年来秦岭太白山林线区3-6月平均气温的重建   总被引:2,自引:0,他引:2  
秦进  白红英  刘荣娟  翟丹平  苏凯  王俊  李书恒 《生态学报》2017,37(22):7585-7594
秦岭太白山林线植被因海拔较高且受人为扰动较轻,对气候变化的响应尤为敏感,为获取过去气候变化信息提供了可靠代用资源。然而,结合树木年代学方法及Arcgis空间插值功能进行秦岭林线气候变化重建的工作至今仍处于空白。利用采自太白山林线地带太白红杉(Larix chinensis)所建立的树轮宽度资料,与提取自太白山保护区气温栅格数据中的采样点位置气象数据进行相关分析。结果表明,太白红杉与3—6月平均气温相关性最显著,采用线性回归建立了两者的拟合模型,剔除重建方程中的1997、1998年之后,方差解释量达57.2%(调整自由度后为55.5%);重建气温序列显示偏冷时段平均跨度(16年)较偏暖时段平均跨度(10.8年)长,偏冷时段有:1870—1881年、1903—1918年和1977—1996年;偏暖的时段有:1882—1892年、1919—1929年和1997—2013年;在1931—1978年这一时期,气温相对稳定,1988年之后升温强烈;周期分析显示近144年以来3—6月气温存在22—31 a,18—22 a以及10—13 a的3个振荡周期,可能与大尺度气候驱动及太阳活动存在联系。以上结果均得到历史记录以及周边重建结果的支持。  相似文献   

20.
Past conservation initiatives and rapidly decreasing human populations in modern Japan have contributed to population recoveries of Sika deer (Cervus nippon), wild boar (Sus scrofa), and Japanese macaque (Macaca fuscata) throughout the country. Ironically, however, these recoveries have not always received a favorable reception, because these mammals can also be agricultural pests. To open public debate on the recoveries, based on a thorough understanding of their multifaceted roles in sustaining the local ecosystem, we evaluated the initial stage ripple effects caused by the mammalian population recovery on the community assembly of dung beetles, which are keystone decomposer organisms in terrestrial ecosystems. For the evaluation, we conducted manipulative snapshot experiments, using camera and pitfall traps, for mammal and dung beetle assemblages, respectively, in four different mountain ranges within the heavy snow areas of northern Japan, where the recovery of three mammal populations was at an early stage. The current findings implied that, although the feces of every recovering mammal species could provide valuable resources for most beetles, the ripple effects from the mammal population recoveries were subject to hysteresis of the local ecosystem, i.e., catastrophic shifts in ecosystems originating from the historical background of regional mammal defaunation. In particular, the abundance of tunnelers that could benefit from positive ripple effects decreased with an increase in past disturbances, which resulted in emptier forests, i.e., an ecosystem with fewer large mammals. The findings suggested that recovering populations of large mammals do not always contribute to the restoration of the original dung beetle communities, at least initially.  相似文献   

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