四川西北高原藏狐的夏季微生境选择

生境选择是动物的重要行为 ,近年来我国学者在该方面做了大量的工作。王梦军等[1] 通过调控牧压研究了达乌尔鼠兔 (Ochotonadauricus)扩散过程中的生境选择 ;姜兆文等[2 ] 采用雪地足迹跟踪法研究了紫貂 (Marteszibellina)冬季生境选择 ;张洪海等[3 ] 用无线电跟踪技术和全球定位系统对紫貂春季和夏季的生境选择进行了研究 ,但比较多的是引入一些选择指数和数学模型 ,使研究更为便捷 ,结果更为直观 ,如 :vanderplaeg和scavia系数[4～ 6] 、栖息地生境偏爱指数PI[7] 、数量化理论[8] 、聚类分析[9] 等。藏狐 (Vulpesferrilata)是青藏高原特…     

Climatological context for large-scale coral bleaching

Large-scale coral bleaching was first observed in 1979 and has occurred throughout virtually all of the tropics since that time. Severe bleaching may result in the loss of live coral and in a decline of the integrity of the impacted coral reef ecosystem. Despite the extensive scientific research and increased public awareness of coral bleaching, uncertainties remain about the past and future of large-scale coral bleaching. In order to reduce these uncertainties and place large-scale coral bleaching in the longer-term climatological context, specific criteria and methods for using historical sea surface temperature (SST) data to examine coral bleaching-related thermal conditions are proposed by analyzing three, 132 year SST reconstructions: ERSST, HadISST1, and GISST2.3b. These methodologies are applied to case studies at Discovery Bay, Jamaica (77.27°W, 18.45°N), Sombrero Reef, Florida, USA (81.11°W, 24.63°N), Academy Bay, Galápagos, Ecuador (90.31°W, 0.74°S), Pearl and Hermes Reef, Northwest Hawaiian Islands, USA (175.83°W, 27.83°N), Midway Island, Northwest Hawaiian Islands, USA (177.37°W, 28.25°N), Davies Reef, Australia (147.68°E, 18.83°S), and North Male Atoll, Maldives (73.35°E, 4.70°N). The results of this study show that (1) The historical SST data provide a useful long-term record of thermal conditions in reef ecosystems, giving important insight into the thermal history of coral reefs and (2) While coral bleaching and anomalously warm SSTs have occurred over much of the world in recent decades, case studies in the Caribbean, Northwest Hawaiian Islands, and parts of other regions such as the Great Barrier Reef exhibited SST conditions and cumulative thermal stress prior to 1979 that were comparable to those conditions observed during the strong, frequent coral bleaching events since 1979. This climatological context and knowledge of past environmental conditions in reef ecosystems may foster a better understanding of how coral reefs will respond in future, ocean warming scenarios.     

Biomass,production and woody detritus in an old coast redwood (<Emphasis Type="Italic">Sequoia sempervirens</Emphasis>) forest

We examined aboveground biomass dynamics, aboveground net primary production (ANPP), and woody detritus input in an old Sequoia sempervirens stand over a three-decade period. Our estimates of aboveground biomass ranged from 3300 to 5800 Mg ha⁻¹. Stem biomass estimates ranged from 3000 to 5200 Mg ha⁻¹. Stem biomass declined 7% over the study interval. Biomass dynamics were patchy, with marked declines in recent tree-fall patches <0.05 ha in size. Larger tree-fall patches approaching 0.2 ha in size were observed outside the study plot. Our estimates of ANPP ranged from 6 to 14 Mg ha⁻¹yr⁻¹. Estimates of 7 to 10 Mg ha⁻¹yr⁻¹ were considered to be relatively accurate. Thus, our estimates based on long-term data corroborated the findings of earlier short-term studies. ANPP of old, pure stands of Sequoia was not above average for temperate forests. Even though production was potentially high on a per stem basis, it was moderate at the stand level. We obtained values of 797 m³ ha⁻¹ and 262 Mg ha⁻¹ for coarse woody detritus volume and mass, respectively. Fine woody detritus volume and mass were estimated at 16 m³ ha⁻¹ and 5 Mg ha⁻¹, respectively. Standing dead trees (or snags) comprised 7% of the total coarse detritus volume and 8% of the total mass. Coarse detritus input averaged 5.7 to 6.9 Mg ha⁻¹yr⁻¹. Assuming steady-state input and pool of coarse detritus, we obtained a decay rate constant of 0.022 to 0.026. The old-growth stand of Sequoia studied had extremely high biomass, but ANPP was moderate and the amount of woody detritus was not exceptionally large. Biomass accretion and loss were not rapid in this stand partly because of the slow population dynamics and low canopy turnover rate of Sequoia at the old-growth stage. Nomenclature: Hickman (1993).     

滇西北县域生物多样性本底调查与评估

中国是世界上生物多样性最丰富的国家之一, 同时也是生物多样性受威胁最严重的国家之一。为了有效保护生物多样性, 2010年国务院批准实施了《中国生物多样性保护战略与行动计划(2010-2030年)》, 划定了32个陆地生物多样性保护优先区, 并设定了开展优先区生物多样性本底调查的战略目标、优先领域与优先行动。为此, 2010-2011年, 环境保护部联合中国科学院和高校的科研人员, 在滇西北开展了18个县的以县域为单元的生物多样性本底示范调查与研究。调查内容包括生态系统(植被类型)和物种两个层次。生态系统主要调查县域内植被类型的多样性, 完成了以群系为单位的植被类型编目; 物种层次主要调查县域内高等植物、脊椎动物、大型真菌的物种多样性组成、数量和用途等, 分析了特有物种和珍稀濒危物种数量等, 完成了县域物种编目。本文基于调查结果, 比较研究了不同县域间的生物多样性组成, 发现植被类型(108个群系)和物种(高等植物4,481种、脊椎动物625种、大型真菌222种)最丰富的县均为玉龙县。同时, 与历史记录对比研究发现, 滇西北的生物多样性分布数据十分欠缺, 严重影响了生物多样性保护的客观有效决策。生物多样性本底调查是生物多样性保护的一项基础工作, 本研究为中国未来开展大规模的生物多样性本底调查与评估提供了案例。     

Diversity,ecology, and seasonality of sand flies (Diptera: Psychodidae) of the Jenin District (Palestinian Territories)

The diversity, ecology, and seasonality for sand flies from two localities in Jenin District, the Palestinian Territories, were studied. A total of 12,579 sand flies (5,420 Phlebotomus and 7,159 Sergentomyia) were collected during the study period. The genera Phlebotomus and Sergentomyia are represented by 13 and nine species and subspecies, respectively. Species account was given for all collected species. CDC light traps yielded 7,649 (60.8%) of the total captured sand flies, while sticky traps and aspirators contributed to 36.4 and 2.8% of the total collected specimens, respectively. Phlebotomus sergenti and P. syriacus showed two peaks, one in July and one in October. Phlebotomus tobbi showed one peak towards the end of the summer in September and August, while P. papatasi showed a bimodal peaks pattern, one in June and one in October. Phlebotomus canaaniticus showed a peak in August. P. perfiliewi transcaucasicus and P. neglectus showed a peak in October. Sergentomyia dentata showed one peak in August and increasing numbers from June to August, declining afterwards. Other species, such as S. theodori, had one peak in June, S. taizi had steady numbers across the summer, and S. christophersi had a peak in August.     

Competition and facilitation may lead to asymmetric range shift dynamics with climate change

Forecasts of widespread range shifts with climate change stem from assumptions that climate drives species' distributions. However, local adaptation and biotic interactions also influence range limits and thus may impact range shifts. Despite the potential importance of these factors, few studies have directly tested their effects on performance at range limits. We address how population‐level variation and biotic interactions may affect range shifts by transplanting seeds and seedlings of western North American conifers of different origin populations into different competitive neighborhoods within and beyond their elevational ranges and monitoring their performance. We find evidence that competition with neighboring trees limits performance within current ranges, but that interactions between adults and juveniles switch from competitive to facilitative at upper range limits. Local adaptation had weaker effects on performance that did not predictably vary with range position or seed origin. Our findings suggest that competitive interactions may slow species turnover within forests at lower range limits, whereas facilitative interactions may accelerate the pace of tree expansions upward near timberline.     

滇西北高山流石滩植物多样性

通过多次对滇西北高山流石滩野外实地考察、标本鉴定并查阅有关献,建立数据库统计得到流石滩种子植物共计29科、103属、519种。其中中国特有植物295种,占总数的56．8％,滇西北特有植物54种,占10．4％。有10种属的分布区类型(包括7个变型),北温带分布类型最多,占总属数的47．5％。在整个高山流石滩中,草本有455种,占总数的87．7％,其中多年生草本421种。流石滩植物中具有多种生态、生理适应方式,低矮平卧状植株、莲座状、垫状、极矮小草本、密集丛生是植物的重要适应方式。根茎及发达的肉质根或木质根是典型流石滩上的主要适应方式,分别占植物总数的19．7％,31．0％。果实中干果共计518种,其中蒴果298种。由于流石滩处于生态脆弱区,人为干扰易对生态系统造成危害。本对流石滩种子植物多样性组成分析,为合理保护和利用流石滩植物资源提供基础资料。     

‘What's larvae got to do with it?’ Disparate patterns of post‐glacial population structure in two benthic marine gastropods with identical dispersal potential

In marine environments, many species have apparently colonized high latitude regions following the last glacial maximum (LGM) yet lack a life-history stage, such as a free-living larva, that is clearly capable of long-distance dispersal. Two hypotheses can explain the modern high latitude distributions of these marine taxa: (1) survival in northern refugia during the LGM or (2) rapid post-glacial dispersal by nonlarval stages. To distinguish these two scenarios, I characterized the genetic structure of two closely related northeastern Pacific gastropods that lack planktonic larvae but which have distributions extending more than 1000 km north of the southern limit of glaciers at the LGM. Despite having identical larval dispersal potential, these closely related species exhibit fundamentally different patterns of genetic structure. In Nucella ostrina, haplotype diversity among northern populations (British Columbia and Alaska) is low, no pattern of isolation by distance exists and a coalescent-based model of population growth indicates that during the LGM population size was reduced to less than 35% of its current size. In the congeneric and often sympatric N. lamellosa, northern populations harbour a diversity of ancient private haplotypes, significant evidence of isolation by distance exists and regional subdivision was found between northern (Alaska) and southern (southern British Columbia, Washington and Oregon) populations. Estimates of coalescent parameters indicate only a modest reduction in population size during the LGM and that northern and southern populations of N. lamellosa split approximately 50 Kyr before the LGM. The patterns are consistent with the hypothesis that N. ostrina recently reinvaded the northeastern Pacific but N. lamellosa survived the LGM in a northern refuge. A comparison of similar studies in this region indicates that depleted levels of genetic variation at high latitudes--evidence suggestive of recent colonization from a southern refuge--is more common among intertidal species that live relatively high on the shore, where exposure times to cold stress in air are longer than for species living lower on the shore. These data suggest that for some faunas, ecological differences between taxa may be more important than larval dispersal potential in determining species' long-term biogeographical responses to climate change.