Influence of Density and Climate on Population Dynamics of a Large Herbivore Under Harsh Environmental Conditions

ABSTRACT Dynamics of herbivore populations can be influenced both by density-dependent processes and climate. We used age-at-harvest data for adult female white-tailed deer (Odocoileus virginianus) collected over 23 years to estimate survival and reproduction by age class and to identify effects of environmental factors. The study population was located on Anticosti Island (QC, Canada), at the northern limit of the species' range; the population was at high density, and the landscape had scarce forage and abundant snow during winter. Despite severe environmental conditions, population growth apparently increased during the study; adult survival was similar to other populations, although reproduction appeared lower. Winter severity was not related to survival, but density affected adult female survival. Density at estrus was the main factor influencing reproduction of 2- and 3–4-year-olds and also affected reproduction of prime-aged females (5–9-yr-olds), but not of older females. Reproductive rate of younger females was influenced by environmental conditions in autumn, such as high density or snow conditions that limited forage availability. Reproductive success of 5–9- and ≥10-year-old females appeared dependent on spring conditions favoring high-quality forage, probably through effects on neonatal survival. Relative to other studies on northern ungulates, demographic processes in our study appeared to be more affected by autumn and spring climate, in addition to population density, than by winter climate. We thus propose that population density, as well as autumn and spring climate, should be considered in management strategies. Harvest data offered a unique opportunity to study forest ungulates, for which individual monitoring is rarely possible.     

Snake diets and the deep history hypothesis

The structure of animal communities has long been of interest to ecologists. Two different hypotheses have been proposed to explain origins of ecological differences among species within present‐day communities. The competition–predation hypothesis states that species interactions drive the evolution of divergence in resource use and niche characteristics. This hypothesis predicts that ecological traits of coexisting species are independent of phylogeny and result from relatively recent species interactions. The deep history hypothesis suggests that divergences deep in the evolutionary history of organisms resulted in niche preferences that are maintained, for the most part, in species represented in present‐day assemblages. Consequently, ecological traits of coexisting species can be predicted based on phylogeny regardless of the community in which individual species presently reside. In the present study, we test the deep history hypothesis along one niche axis, diet, using snakes as our model clade of organisms. Almost 70% of the variation in snake diets is associated with seven major divergences in snake evolutionary history. We discuss these results in the light of relevant morphological, behavioural, and ecological correlates of dietary shifts in snakes. We also discuss the implications of our results with respect to the deep history hypothesis. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 476–486.     

三烯生育酚生物学功能及合成调控研究进展

介绍了三烯生育酚的生物合成途径,重点综述了三烯生育酚在神经保护、抗癌、降低胆固醇以及抗氧化等方面的优越生物学功能,以及利用关键酶的高效表达和前体物质水平的提高等植物代谢工程手段提高植物体内三烯生育酚生物合成水平的研究进展。     

脂质组学研究进展

综述了脂质组学的研究现状和发展趋势.脂质组学是对生物体、组织或细胞中的脂质以及与其相互作用的分子进行系统分析的一门新兴学科.脂质具有多种重要的生物功能,脂质代谢异常可引发诸多人类疾病,包括糖尿病、肥胖症、癌症以及神经退行性疾病等.目前,脂质组学研究已成为一个前景广阔的热门领域,并广泛地应用到包括药物研发、分子生理学、分子病理学、功能基因组学、营养学以及环境与健康等重要领域.     

氮磷添加对红壤区城郊湿地松林凋落叶分解的影响

城市化易导致城市森林氮(N)沉降和磷(P)富集,进而对凋落物分解过程产生影响。以位于南昌市郊的湿地松(Pinuse lliottii Engelm.)林为研究对象,采用尼龙网袋分解法,模拟N沉降(10g N·m-2·a-1,[N])、P积累(2.5g P·m-2·a-1,[P])和N沉降+P积累(10N·m-2·a-1+2.5g P·m-2·a-1,[N+P])对凋落叶分解速率与C、N、P含量及其化学计量比动态变化的影响。结果表明:与对照(CK)相比,[N]、[P]和[N+P]均促进凋落叶的前期(0～180d)分解速率,抑制中期(180～360d)、后期(360～540d)的分解速率;至540d时分解速率表现为[N]、[P]和CK无差异,但均高于[N+P](P0.05)。[N]提高分解过程中凋落叶N浓度,N含量表现为分解前期积累、后期释放;[P]提高分解过程中凋落叶P浓度,P含量持续积累;[N+P]提高N和P浓度,分解前期N、P含量积累,后期释放;而不同处理的C含量均表现为释放。凋落物基质C/N/P比与分解速率的相关性随分解阶段而表现各异。综合来看,城市化导致的N沉降和P富集叠加效应具有抑制城市森林凋落物分解过程的潜在性。     

Industrial Recycling Networks as Starting Points for Broader Sustainability‐Oriented Cooperation?

Closing loops by intercompany recycling of by‐products is a core theme of industrial ecology (IE). This article considers whether industrial recycling networks or industrial symbiosis projects can be used as a starting point for much broader intercompany cooperation for sustainable development. Evidence presented is based on the results of an empirical investigation of the recycling network Styria in Austria, the recycling network Oldenburger Münsterland in Germany, and the manufacturing sector in Austria. Statistical analysis shows that the percentage of by‐products that are passed on to other companies for recycling purposes is not higher in member companies of the recycling networks than in the other companies of the manufacturing sector in Austria. In terms of cooperation, the relationships with the respective recycling partners are found to be very similar to regular customer relations. Furthermore, the companies of the recycling networks remain unaware of the network to which they belong. Instead, one of the main findings of this study is that intercompany recycling activities are regarded by the company representatives as bilateral market transactions, not as collaborative network activities. This has potentially significant implications for the use of industrial symbiosis networks as starting points for sustainability networks with broader cooperation toward sustainability. The findings raise interesting questions as to whether such broader cooperation might result from a conscious planning process or might emerge largely spontaneously as part of normal market coordination. In any case, intercompany recycling is clearly considered to be a very important field of collaborative action for sustainability in industry.     

Life Cycle Assessment of Water Supply Plans in Mediterranean Spain

Life cycle assessment (LCA) was used to compare the current water supply planning in Mediterranean Spain, the so‐called AGUA Programme, with its predecessor, the Ebro river water transfer (ERWT). Whereas the ERWT was based on a single interbasin transfer, the AGUA Programme excludes new transfers and focuses instead on different types of resources, including seawater and brackish water desalination and wastewater reuse, among others. The study includes not only water supply but the whole anthropic cycle of water, from water abstraction to wastewater treatment. In addition to standard LCA impact categories, a specific impact category focusing on freshwater resources is included, which takes into account freshwater scarcity in the affected water catchments. In most impact categories the AGUA Programme obtains similar or even lower impact scores than ERWT. Concerning impacts on freshwater resources, the AGUA Programme obtains an impact score 49% lower than the ERWT. Although the current water planning appears to perform better in many impact categories than its predecessor, this study shows that water supply in Spanish Mediterranean regions is substantially increasing its energy intensity and that Mediterranean basins suffer a very high level of water stress due to increasing demand and limited resources.     

Ecological biogeography of Malagasy non‐volant mammals: community structure is correlated with habitat

Aim To examine the relationship between ecoregions, as a proxy for regional climate and habitat type, and mammalian community structure, defined by species composition and richness (e.g. taxonomic structure) and ecological diversity (e.g. ecological structure) of non‐volant species. Location Madagascar. Methods Faunal lists of non‐volant mammal species occurring in 35 communities from five World Wildlife Fund ecoregions were collected from published and unpublished sources. Species were assigned to ecological groups defined by trophic status, locomotor habits, activity cycle and body mass. We used Mantel tests, cluster analysis and principal coordinates analysis to evaluate geographic patterning in taxonomic composition and species richness. We used stepwise multiple discriminant analysis to characterize patterns in the ecological diversity of the mammalian communities from each ecoregion. Communities from transitional habitats (e.g. representing more than one ecoregion) were used to test the predictive power of the analyses. Results Non‐volant mammal communities divided into clusters that correspond to ecoregions. There was a strong distance effect in the taxonomic structure of communities across the island and within both humid and dry forest communities, but this effect was weak within humid forest communities. Mammalian species richness was significantly lower in dry forest than in humid forest communities. The ecological structure of communities was also correlated with ecoregions. Changes in the relative percentages of omnivory, arboreal quadrupedalism, terrestrial/arboreal quadrupedalism and two body mass classes accounted for 98.1% of the variation in ecological structure. Transitional communities were projected in intermediate positions by the discriminant model. Main conclusions Our analysis demonstrates that the broad‐scale habitat and climate variables captured by the ecoregion model have shaped the assembly of non‐volant mammal communities in Madagascar over evolutionary time. The spatial pattern is consistent with ecological sorting of species ranges along environmental gradients. Historical processes, such as recent extinction and migration, may have also affected the structure of mammal communities, although these factors have played a secondary role.     

The influence of moisture on the suppression of Pseudomonas syringae by Aureobasidium pullulans on an artificial leaf surface

Abstract Isolates of Aureobasidium pullulans which produce antibacterial metabolites were compared with non-antibiotic-producing isolates of Tremella foliacea and Trichosporon beigelii for their ability to inhibit growth of Pseudomonas syringae pv phaseolicola . The bacteria and fungi were co-inoculated on an artificial leaf surface under conditions of low and high water availability. Under conditions of excess moisture, antibiotic production gave no advantage to the Aureobasidium isolates, and all the yeasts were equally antagonistic. Under drier conditions the Aureobasidium isolates reduced the population of P. syringae by 96–99%, a result which was significantly different from that which occurred when the bacteria were co-inoculated with the other yeasts under these conditions. An antibacterial compound, similar to that produced in liquid culture by Aureobasidium , was detected in washings from the artificial leaf surface following growth of this species.