Plant Community Structure and Conservation of a Northern Peru Sclerophyllous Forest

The vegetation near El Bosque Petrificado Piedra Chamana, in the northern Peruvian Andes, is evergreen sclerophyllous forest with significant shrub, epiphyte, and mat components. Important/characteristic genera include Dodonaea, Polylepis, Oreopanax, Oreocallis, Myrcianthes, and the mat-forming orchid Pleurothallis. A vegetation survey including 12 transects and 240 plots in high- and low-grazed areas documented 96 plant species. Compared with low-grazed areas, high-grazed areas had significantly fewer tree species, more herbs, and higher density of individuals. Both grazing categories exhibited high connectedness (as seen in network metrics) and positive biotic associations (nestedness), suggesting facilitation of some species by others, but high-grazed areas showed greater indications of positive associations (as seen in the C-score and V-ratio). These positive biotic associations may relate to the harsh environment and the role of keystone taxa such as Dodonaea viscosa, canopy trees, and mat-forming elements in moderating conditions and promoting species establishment. Only in the low-grazed areas was there any indication of competitive interactions (negative C-score/ less than expected species-pair occurrence). The shift in sign of the C-score, from negative in low-grazed areas to positive in high-grazed areas, indicates a loss of competitive interactions as a factor influencing community structure where grazing pressure is higher. Conservation of the area's natural resources would be advanced by protection of areas where the vegetation structure is more intact, better controls on grazing animals, and identification of development alternatives that would reduce pressure on the area's unique vegetation.     

红松林不同演替阶段夏季鸟类群落研究

红松林不同演替阶段夏季鸟类群落研究常家传鲁长虎刘伯文许青（东北林业大学,哈尔滨１５００４０）ＳｔｕｄｙｏｆｔｈｅＢｉｒｄｓＣｏｍｍｕｎｉｔｙＳｔｒｕｃｔｕｒｅｉｎＤｉｆｅｒｅｎｔＳｕｃｃｅｓｉｏｎＰｅｒｉｏｄｏｆＫｏｒｅａｎＰｉｎｅＦｏｒｅｓｔ．Ｃｈ...     

Calculating Climate Effects on Birds and Mammals: Impacts on Biodiversity, Conservation, Population Parameters, and Global Community Structure

This paper describes how climate variation in time and spacecan constrain community structure on a global scale. We explorebody size scaling and the energetic consequences in terms ofabsorbed mass and energy and expended mass and energy. We explainhow morphology, specific physiological properties, and temperaturedependent behaviors are key variables that link individual energeticsto population dynamics and community structure. This paper describes an integrated basic principles model formammal energetics and extends the model to bird energetics.The model additions include molar balance models for the lungsand gut. The gut model couples food ingested to respiratorygas exchanges and evaporative water loss from the respiratorysystem. We incorporate a novel thermoregulatory model that yieldsmetabolic calculations as a function of temperature. The calculationsmimic empirical data without regression. We explore the differencesin the quality of insulation between hair and feathers withour porous media model for insulation. For mammals ranging in size from mice to elephants we show thatcalculated metabolic costs are in agreement with experimentaldata. We also demonstrate how we can do the same for birds rangingin size from hummingbirds to ostriches. We show the impact ofchanging posture and changing air temperatures on energeticcosts for birds and mammals. We demonstrate how optimal bodysize that maximizes the potential for growth and reproductionchanges with changing climatic conditions and with diet quality.Climate and diet may play important roles in constraining communitystructure (collection of functional types of different bodysizes) at local and global scales. Thus, multiple functionaltypes may coexist in a locality in part because of the temporaland spatial variation in climate and seasonal food variation.We illustrate how the models can be applied in a conservationand biodiversity context to a rare and endangered species ofparrot, the Orange-bellied Parrot of Australia and Tasmania.     

Emerging Evidence on the Effectiveness of Tropical Forest Conservation

The PLOS ONE Collection “Measuring forest conservation effectiveness” brings together a series of studies that evaluate the effectiveness of tropical forest conservation policies and programs with the goal of measuring conservation success and associated co-benefits. This overview piece describes the geographic and methodological scope of these studies, as well as the policy instruments covered in the Collection as of June 2016. Focusing on forest cover change, we systematically compare the conservation effects estimated by the studies and discuss them in the light of previous findings in the literature. Nine studies estimated that annual conservation impacts on forest cover were below one percent, with two exceptions in Mexico and Indonesia. Differences in effect sizes are not only driven by the choice of conservation measures. One key lesson from the studies is the need to move beyond the current scientific focus of estimating average effects of undifferentiated conservation programs. The specific elements of the program design and the implementation context are equally important factors for understanding the effectiveness of conservation programs. Particularly critical will be a better understanding of the causal mechanisms through which conservation programs have impacts. To achieve this understanding we need advances in both theory and methods.     

Soil Calcium and Forest Birds: Indirect Links Between Nutrient Availability and Community Composition

Calcium is an important nutrient that can be limiting in many forest ecosystems, where acid deposition and other natural and anthropogenic activities have resulted in significant soil calcium depletion. Calcium’s critical role in physiological and structural processes and its limited mobility and storage in many organisms, make it a potential driver of ecosystem structure and function, but little is known about how changes in soil calcium affect community composition, especially in terrestrial vertebrates. The aim of this study was to establish relationships between the abundances of forest songbird species and soil calcium and to elucidate linking mechanisms by establishing simultaneous relationships with trophic and habitat variables. We measured soil calcium and pH, calcium-rich invertebrate abundances, vegetation, and songbird abundances at 14 interior forest sites across central Pennsylvania representing a range of soil calcium levels. Bird community composition varied with soil calcium and pH, with 10 bird species having the highest abundances in forests with high calcium soils, and five species having the highest abundances with low calcium soils. Bird species associated with low-calcium soils were associated with high densities of mountain laurel (Kalmia latifolia), an acid-loving shrub, whereas bird species associated with high-calcium soils were associated with high densities of saplings and high basal area of acid-sensitive tree species. Homogenization of soil conditions through land-use patterns and soil calcium depletion pose the risk of reducing the beta diversity of bird species across forest areas because community composition varied with soil calcium.     

Community Structure of Yeast Fungi in Forest Biogeocenoses

The results of longterm studies of yeasts inhabiting soil, plant surfaces, and plant residues in typical subboreal forests of the European part of Russia are summarized. The cell number and species diversity of yeast communities in the array of substrates corresponding to succession stages in plant residue decomposition are shown to steadily decline. Each stage is characterized by its specific set of dominating species. The yeast diversity in forest biogeocenoses is shown to surpass that in other geographic zones. This manifests itself in a greater number of species occurring in similar arrays of substrates, in the absence of conspicuous dominants on the biogeocenotic level, and in a higher differentiation of the yeast population with respect to its habitat type. The forest yeast populations are also characterized by a high diversity of yeasts of ascomycetous affinity and of the anamorphic stages of Taphrinales and Tremellales and by the presence of typical pedobiont species (except Lipomyces spp.).     

天际岭森林公园夏季鸟类群落调查及多样性研究

2003年夏季,对天际岭国家森林公园的鸟类群落进行了调查,共发现有鸟类39种,隶属于11目26科34属.通过对不同地区鸟类群落的比较研究,结果表明植物群落的垂直结构和水平格局对鸟类群落的多样性具有直接影响.     

Spatial Structure Facilitates Cooperation in a Social Dilemma: Empirical Evidence from a Bacterial Community

Cooperative organisms are ubiquitous in nature, despite their vulnerability to exploitation by cheaters. Although numerous theoretical studies suggest that spatial structure is critical for cooperation to persist, the spatial ecology of microbial cooperation remains largely unexplored experimentally. By tracking the community dynamics of cooperating (rpoS wild-type) and cheating (rpoS mutant) Escherichia coli in well-mixed flasks and microfabricated habitats, we demonstrate that spatial structure stabilizes coexistence between wild-type and mutant and thus facilitates cooperator maintenance. We develop a method to interpret our experimental results in the context of game theory, and show that the game wild-type and mutant bacteria play in an unstructured environment changes markedly over time, and eventually obeys a prisoner’s dilemma leading to cheater dominance. In contrast, when wild-type and mutant E. coli co-inhabit a spatially-structured habitat, cooperators and cheaters coexist at intermediate frequencies. Our findings show that even in microhabitats lacking patchiness or spatial heterogeneities in resource availability, surface growth allows cells to form multi-cellular aggregates, yielding a self-structured community in which cooperators persist.     

Structure of the Epiphyte Community in a Tropical Montane Forest in SW China

Vascular epiphytes are an understudied and particularly important component of tropical forest ecosystems. However, owing to the difficulties of access, little is known about the properties of epiphyte-host tree communities and the factors structuring them, especially in Asia. We investigated factors structuring the vascular epiphyte-host community and its network properties in a tropical montane forest in Xishuangbanna, SW China. Vascular epiphytes were surveyed in six plots located in mature forests. Six host and four micro-site environmental factors were investigated. Epiphyte diversity was strongly correlated with host size (DBH, diameter at breast height), while within hosts the highest epiphyte diversity was in the middle canopy and epiphyte diversity was significantly higher in sites with canopy soil or a moss mat than on bare bark. DBH, elevation and stem height explained 22% of the total variation in the epiphyte species assemblage among hosts, and DBH was the most important factor which alone explained 6% of the variation. Within hosts, 51% of the variation in epiphyte assemblage composition was explained by canopy position and substrate, and the most important single factor was substrate which accounted for 16% of the variation. Analysis of network properties indicated that the epiphyte host community was highly nested, with a low level of epiphyte specialization, and an almost even interaction strength between epiphytes and host trees. Together, these results indicate that large trees harbor a substantial proportion of the epiphyte community in this forest.     

滹沱河湿地石家庄段水鸟群落结构及多样性

2003年3月～2006年4月,对滹沱河湿地石家庄段水鸟进行了调查。共记录水鸟80种,隶属于7目16科。其中候鸟73种(夏候鸟、冬候鸟和旅鸟),留鸟7种;古北种62种,东洋种11种,广布种7种;国家Ⅰ、Ⅱ级重点保护鸟类11种。鸻形目和雁形目鸟类占优势,各占水鸟种数的35.00%和30.00%。水鸟种类和数量高峰出现在4月和11月,低谷在1月和2月。多样性分析表明,冶河-黄壁庄水库和滹沱河-岗南水库Shannon-Weiner指数和G-F指数均高于石板水库,这与湿地面积和生境的多样性有关。滹沱河湿地石家庄段作为许多水鸟,尤其是黑鹳的重要栖息地,需进一步加强监测和保护。     

乌鲁木齐南部山区森林生态系统树生地衣群落结构

为了探明乌鲁木齐南部山区树生地衣种类及其群落结构特征,应用多元分析中的主成分分析及聚类分析方法,对分布在乌鲁木齐南部山区森林生态系统中的树生地衣植物群落进行数量分类,并对其群落结构的物种多样性、相似性和均匀度等群落参数进行了比较系统的研究。结果表明,分布在乌鲁木齐南部山区的树生地衣共有39种,隶属于5目13科26属。根据多元分析结果,将该地区的树生地衣划分为3种类型：（1）小茶渍（Lecanorahageni（Ach．）Ach．）＋蜈蚣衣（肋归ciastellaris（L．）Nyl．）＋柳茶渍（￡-。saligna（Schrad．）Zahlbr．）群落;（2）斑面蜈蚣衣（Physciaaipolia（Humb．）Furm．）＋对开蜈蚣衣（Ph．dimidiata（Arn．）Nyl．）＋喇叭石蕊（Cladoniapyxidata（L．）Hoffm．）群落：（3）拟石黄衣（Xanthoria fallax（Hepp）Arnold．）＋丽石黄衣（xelegans（Link．）Th．Fr．）群落。群落3的多样性指数最大,为1．509,其次为群落2,其多样性指数为1．109,群落1的多样性指数最低,为1．088。同时,研究发现海拔高度和树种是影响乌鲁木齐南部山区森林生态系统树生地衣结构的两个重要因素。     

乌鲁木齐南部山区森林生态系统树生地衣群落结构

为了探明乌鲁木齐南部山区树生地衣种类及其群落结构特征, 应用多元分析中的主成分分析及聚类分析方法, 对分布在乌鲁木齐南部山区森林生态系统中的树生地衣植物群落进行数量分类, 并对其群落结构的物种多样性、相似性和均匀度等群落参数进行了比较系统的研究。结果表明, 分布在乌鲁木齐南部山区的树生地衣共有39种, 隶属于5目13科26属。根据多元分析结果, 将该地区的树生地衣划分为3种类型: (1) 小茶渍(Lecanora hageni (Ach.) Ach.) + 蜈蚣衣(Physcia stellaris (L.) Nyl.) + 柳茶渍(L. saligna (Schrad.) Zahlbr.)群落; (2) 斑面蜈蚣衣(Physcia aipolia (Humb.) Furm.) + 对开蜈蚣衣(Ph. dimidiata (Arn.) Nyl.) + 喇叭石蕊(Cladonia pyxidata (L.) Hoffm.)群落; (3) 拟石黄衣(Xanthoria fallax (Hepp) Arnold.) + 丽石黄衣(X. elegans (Link.) Th. Fr.)群落。群落3的多样性指数最大, 为1.509, 其次为群落2, 其多样性指数为1.109, 群落1的多样性指数最低, 为1.088。同时, 研究发现海拔高度和树种是影响乌鲁木齐南部山区森林生态系统树生地衣结构的两个重要因素。     

Distress Calls of Birds in a Neotropical Cloud Forest1

Distress calls are loud, harsh calls given by some species of birds when they are captured by a predator or handled by humans. We recorded the frequency of distress calls and struggling behavior in 40 species of birds captured in mist nets during the dry season in a Costa Rica cloud forest. We tested the following hypotheses proposed to explain the function of distress calls: (1) calling for help from kin or reciprocal altruists; (2) warning kin; (3) eliciting mobbing behavior; (4) startling the predator; and (5) distracting the predator through attraction of additional predators. Our results did not support the calling‐for‐help, warning kin, or mobbing hypotheses. Indeed, genera that regularly occurred with kin or in flocks were not more likely to call than non‐flocking genera. There was no relationship between calling frequency and struggling behavior as predicted by the predator startle hypothesis. Genera of larger birds tended to call more than smaller birds, providing some support for both the predator distraction hypothesis and predator startle hypotheses. Calls of higher amplitude may be more effective in startling the predator. Distress calls of larger birds may also travel greater distances than those of smaller birds, supporting the predator manipulation hypothesis, but this requires further testing.     

中国两个气候过渡区森林土壤线虫群落的比较研究

为比较不同气候过渡区地带性森林土壤线虫群落结构和多样性,以南亚热带向中亚热带气候过渡区的石门台常绿阔叶林和北亚热带向暖温带气候过渡区的鸡公山落叶阔叶林为样地,探讨不同气候区土壤微食物网能流方式的差异。结果表明,石门台土壤线虫群落属数(S)、生物量(Biomass)、多样性指数(H')、丰富度指数(SR)、成熟度指数(MI)和结构指数(SI)在表层土壤(0~10 cm)均显著高于鸡公山。石门台的土壤线虫通路指数(NCR)均值高于0.5,而鸡公山的NCR均值小于0.5,说明前者土壤食物网可能偏向于细菌能流通道,而后者偏向于真菌能流通道,这也与食细菌线虫、食真菌线虫生物量的计算结果一致。可见线虫群落结构确实存在明显的南北差异,并较好地指示了土壤能流和养分循环状况。     

Fungal Community Shifts in Structure and Function across a Boreal Forest Fire Chronosequence

Forest fires are a common natural disturbance in forested ecosystems and have a large impact on the microbial communities in forest soils. The response of soil fungal communities to forest fire is poorly documented. Here, we investigated fungal community structure and function across a 152-year boreal forest fire chronosequence using high-throughput sequencing of the internal transcribed spacer 2 (ITS2) region and a functional gene array (GeoChip). Our results demonstrate that the boreal forest soil fungal community was most diverse soon after a fire disturbance and declined over time. The differences in the fungal communities were explained by changes in the abundance of basidiomycetes and ascomycetes. Ectomycorrhizal (ECM) fungi contributed to the increase in basidiomycete abundance over time, with the operational taxonomic units (OTUs) representing the genera Cortinarius and Piloderma dominating in abundance. Hierarchical cluster analysis by using gene signal intensity revealed that the sites with different fire histories formed separate clusters, suggesting differences in the potential to maintain essential biogeochemical soil processes. The site with the greatest biological diversity had also the most diverse genes. The genes involved in organic matter degradation in the mature forest, in which ECM fungi were the most abundant, were as common in the youngest site, in which saprotrophic fungi had a relatively higher abundance. This study provides insight into the impact of fire disturbance on soil fungal community dynamics.     

Community Structure of Wetland Birds During Spring Migration Through the Rainwater Basin

Abstract: Staging areas and migratory stopovers of wetland birds have the potential to function as geographic bottlenecks; entire populations within a flyway may be affected by the quality and quantity of available wetland habitat at stopover sites. Although approximately 90% of playa wetlands in the Rainwater Basin (RWB) region of south-central Nebraska, USA, have been destroyed, the area still provides essential stopover habitat for >10 million waterfowl each spring. We evaluated community patterns and species associations to assess importance of assembly rules in structuring wetland bird communities during migration and to better facilitate multispecies conservation and management strategies. We surveyed 36–40 playas twice weekly in the RWB and observed approximately 2.6 million individual migratory wetland birds representing 72 species during 3 spring migrations 2002–2004. We evaluated spatial and temporal species co-occurrence patterns of geese, dabbling ducks, diving ducks, and shorebirds using null model analysis. Goose species co-occurrence scores did not differ from random in any year of the study, suggesting that goose species frequently use the same habitats during migration. Co-occurrence patterns among dabbling ducks were not different than expected by chance in any year; however, when we evaluated co-occurrence at a weekly scale, dabbling ducks co-occurred less often than expected during weeks of peak migration (high abundance), indicating that dabbling duck species spatially segregated at high densities. Diving duck co-occurrence patterns did not differ from random in any year, suggesting that diving duck species used the same habitats during migration. Shorebird species co-occurred less often than expected in 2002 and 2004, and during weeks of high shorebird abundance, indicating that shorebird communities were distinctly structured during those times. Most association values among lesser snow geese (Chen caerulescens) and dabbling duck species were positive, indicating dabbling ducks did not avoid wetlands with snow geese, a concern for waterfowl managers. However, we frequently observed snow geese and dabbling ducks using different microhabitats within a wetland, which indicate species associations and co-occurrence patterns may have occurred at a finer spatial scale than we measured. This approach of co-occurrence analysis will allow wildlife managers charged with multispecies management at migration stopover sites to make informed conservation and management decisions based on community structure rather than historic single-species approaches.     

The Effects of Soil Bacterial Community Structure on Decomposition in a Tropical Rain Forest

Soil microorganisms are key drivers of terrestrial biogeochemical cycles, yet it is still unclear how variations in soil microbial community composition influence many ecosystem processes. We investigated how shifts in bacterial community composition and diversity resulting from differences in carbon (C) availability affect organic matter decomposition by conducting an in situ litter manipulation experiment in a tropical rain forest in Costa Rica. We used bar-coded pyrosequencing to characterize soil bacterial community composition in litter manipulation plots and performed a series of laboratory incubations to test the potential functional significance of community shifts on organic matter decomposition. Despite clear effects of the litter manipulation on soil bacterial community composition, the treatments had mixed effects on microbial community function. Distinct communities varied in their ability to decompose a wide range of C compounds, and functional differences were related to both the relative abundance of the two most abundant bacterial sub-phyla (Acidobacteria and Alphaproteobacteria) and to variations in bacterial alpha-diversity. However, distinct communities did not differ in their ability to decompose native dissolved organic matter (DOM) substrates that varied in quality and quantity. Our results show that although resource-driven shifts in soil bacterial community composition have the potential to influence decomposition of specific C substrates, those differences may not translate to differences in DOM decomposition rates in situ. Taken together, our results suggest that soil bacterial communities may be either functionally dissimilar or equivalent during decomposition depending on the nature of the organic matter being decomposed.