关键词： 白马人   山、树和动物崇拜   万物有灵   生态意蕴  

摘要： 山、树和动物崇拜是白马民间信仰的重要内容,在白马人精神世界占有重要地位。极为不利于农业生产的生存环境加剧了白马人对山、树和动物等生存资源的依赖,而正是这一依赖孕育了白马人山、树和动物崇拜意识。虽然,在白马人的山、树和动物崇拜的具体实践中从未提及"环境意识"这一概念,但它所蕴含的丰富的生态思想客观上具有保护生态环境的重要作用。

关键词： Biodiversity   biogeography   biotic elements   conservation biogeography   distribution patterns   open areas   reptiles   South American savanna  

摘要： Aim To test predictions of the vicariance model, to define basic biogeographical units for Cerrado squamates, and to discuss previous biogeographical hypotheses. Location Cerrado;South American savannas south of the Amazon, extending across central Brazil, with marginal areas in Bolivia and Paraguay and isolated relictual enclaves in adjacent regions. Methods We compiled species occurrence records via field sampling and revision of museum specimens and taxonomic literature. All species were mapped according to georeferenced locality records, and classified as (1) endemic or non-endemic, (2) typical of plateaus or depressions, and (3) typical of open or forested habitats. We tested predictions of the vicariance model using biotic element analysis, searching for non-random clusters of species ranges. Spatial congruence of biotic elements was compared with putative areas of endemism revealed by sympatric restricted-range species. Effects of topographical and vegetational mosaics on distribution patterns were studied according to species composition in biotic elements and areas of endemism. Results We recorded 267 Cerrado squamates, of which 103 (39%) are endemics, including 20 amphisbaenians (61% endemism), 32 lizards (42%) and 51 snakes (32%). Distribution patterns corroborated predictions of the vicariance model, revealing groups of species with significantly clustered ranges. An analysis of endemic species recovered seven biotic elements, corroborating results including non-endemics. Sympatric restricted-range taxa delimited 10 putative areas of endemism, largely coincident with core areas of biotic elements detected with endemic taxa. Distribution patterns were associated with major topographical and vegetational divisions of the Cerrado. Endemism prevailed in open, elevated plateaus, whereas faunal interchange, mostly associated with forest habitats, was more common in peripheral depressions. Main conclusions Our results indicate that vicariant speciation has stro

关键词： FOSSILS   MOLECULAR biology   EVOLUTION (Biology)   CALIBRATION   PHYLOGENY   DIVERGENCE (Biology)   PROBABILITY theory  

摘要： Lee, M. S. Y. & Skinner, A. (2011). Testing fossil calibrations for vertebrate molecular trees. —Zoologica Scripta, 40, 538–543.

关键词： ANIMALS -- Population biology   HERBIVORES   SOUTHERN oscillation   DEMOGRAPHIC change   BIODIVERSITY   POPULATION dynamics  

摘要： Our understanding of large-scale climatic phenomena and dynamics of large herbivore populations comes principally from research in northern regions with temperate, seasonal climate and animal communities with relatively low species diversity. To assess the generality of that perspective, we investigated effects of El Nino-Southern Oscillation (ENSO) on population dynamics of African buffalo Syncerus caff er inhabiting a semi-arid savanna with variable rainfall. We used linear and nonlinear-threshold models to investigate relationships between population parameters and explanatory variables affecting forage conditions (seasonal rainfall, Southern Oscillation Index [SOI]). El Nino-related droughts in 1982-1983 and 1991-1992 were associated with strongly negative population change, a pattern expected to coincide with a decrease in normally high and constant adult survival. Consistent with that nonlinear pattern, we detected threshold relationships between wet-season rainfall and population change. Juvenile recruitment was described best by linear relationships with dry-season. Because ENSO operates primarily through wet-season rainfall, whereas population dynamics were also related to dry-season rainfall, SOI did not have the predictive ability of individual weather components.

关键词： Acacia drepanolobium   African savanna   demography   herbivory   Kenya Long-term Exclosure Experiment   lambda   matrix model   Mpala Research Centre, Kenya   rodent   seed predation   tree recruitment   ungulate  

摘要： Plant populations are regulated by a diverse array of herbivores that impose demographic filters throughout their life cycle. Few studies, however, simultaneously quantify the impacts of multiple herbivore guilds on the lifetime performance or population growth rate of plants. In African savannas, large ungulates (such as elephants) are widely regarded as important drivers of woody plant population dynamics, while the potential impacts of smaller, more cryptic herbivores (such as rodents) have largely been ignored. We combined a large-scale ungulate exclusion experiment with a five-year manipulation of rodent densities to quantify the impacts of three herbivore guilds (wild ungulates, domestic cattle, and rodents) on all life stages of a widespread savanna tree. We utilized demographic modeling to reveal the overall role of each guild in regulating tree population dynamics, and to elucidate the importance of different demographic hurdles in driving population growth under contrasting consumer communities. We found that wild ungulates dramatically reduced population growth, shifting the population trajectory from increase to decline, but that the mechanisms driving these effects were strongly mediated by rodents. The impact of wild ungulates on population growth was predominantly driven by their negative effect on tree reproduction when rodents were excluded, and on adult tree survival when rodents were present. By limiting seedling survival, rodents also reduced population growth;however, this effect was strongly dampened where wild ungulates were present. We suggest that these complex interactions between disparate consumer guilds can have important consequences for the population demography of long-lived species, and that the effects of a single consumer group are often likely to vary dramatically depending on the larger community in which interactions are embedded.

关键词： BIODIVERSITY   PREDATORY animals   SAVANNAS   PLANT ecology   WOODY plants  

摘要： Despite the well-documented impacts of consumers on seed abundance the link between seed predation and plant population dynamics remains poorly understood because experimental studies linking patterns of predation with seedling establishment are rare. We used experimental manipulations with six woody plant species to elucidate the effects of seed predator type, habitat, and plant species identity on rates of seed predation and seedling recruitment in the Neotropical savannas known as the Cerrado. We found that seed predation rates are consistently high across a diversity of local habitat types, with important inter-habitat variation in seed predation for three of the six species used in our experiments. We also found that seed predation has a clear demographic signal - experimentally excluding predators resulted in higher rates of seedling establishment over the course of two seasons. Because the intensity of seed predation varied between species and habitats, it may play a role in structuring local patterns of plant abundance and community composition. Finally, our results lend support to the recent hypothesis that herbivores have major and underappreciated impacts in Neotropical savannas, and that top-down factors can influence the demography of plants in this extensive and biodiversity-rich biome in previously unexplored ways.

关键词： frugivorous vertebrate   scatter-hoarding rodents   Scleropyrum wallichianum   seed dispersal   seedling recruitment  

摘要： Local extinction or population decline of large frugivorous vertebrates as primary seed dispersers,caused by hu-man disturbance and habitat change,might lead to dispersal limitation of many large-seeded fruit ***,it is not known whether or not scatter-hoarding rodents as secondary seed dispersers can help maintain natural regeneration(*** dispersal)of these frugivore-dispersed trees in the face of the functional reduction or loss of primary seed *** the present study,we investigated how scatter-hoarding rodents affect the fate of tagged seeds of a large-seeded fruit tree(Scleropyrum wallichianum Arnott,1838,Santalaceae)from seed fall to seedling establishment in a heavily defaunated tropical forest in the Xishuangbanna region of Yunnan Province,in south-west China,in 2007 and *** results show that:(i)rodents removed nearly all *** seeds in both years;(ii)a large proportion(2007,75%;2008,67.5%)of the tagged seeds were cached individually in the surface soil or under leaf litters;(iii)dispersal distance of primary caches was further in 2007(19.6±14.6 m)than that in 2008(14.1±11.6 m),and distance increased as rodents recovered and moved seeds from primary caches into subsequent caching sites;and(iv)part of the cached seeds(2007,3.2%;2008,2%)survived to the seedling stage each *** study suggests that by taking roles of both primary and secondary seed dispersers,scatter-hoarding rodents can play a significant role in maintaining seedling establishment of ***,and are able to at least partly compensate for the loss of large frugivorous vertebrates in seed dispersal.

关键词： Folivora   Sloth   Deseadan   Eocene-Oligocene turnover   Grazing   South America  

摘要： We describe a new taxon of mylodontid sloth from the late Oligocene (Deseadan South American Land Mammal "age"), Salla Beds of Bolivia. This taxon, Paroctodontotherium calleorum, new genus and species, is one of the oldest known sloths, but it is surprisingly derived. It is referable to the Mylodontidae and, with just a little doubt, to the Mylodontinae. It shares a number of derived characteristics with other mylodontids and even mylodontines. These include: a relatively low temporomandibular joint;a relatively short zygomatic process of the squamosal;an elongated, narrow braincase;anteriorly diverging toothrows;broad muzzle;and greatly enlarged external nares. The relative width of the muzzle of Paroctodontotherium is as great as any Pleistocene mylodontid except the giant grazer, Lestodon. We review and critique methods of estimating diets of extinct sloths and propose a hypothesis in regard to the feeding ecology of Paroctodontotherium. Based upon its broad muzzle, the degree of tooth wear, and its presence in a habitat dominated by hypsodont herbivores, we propose that Paroctodontotherium was a bulk feeder that foraged near ground level. Grasses were likely a major component of its diet. The addition of this new taxon, along with other recently discovered taxa, illustrates that late Oligocene sloths had much greater diversity than recognized just a decade ago. This diversity is evident in species richness, variations in body sizes, dental morphologies, and means of locomotion. We regard this relatively sudden sloth radiation as a significant component of the Eocene-Oligocene faunal turnover and was related to the development of more open habitats of post-Eocene South America.

关键词： nutrient cycling   tree competition   herbivores defense   Competition   Security   herbivores   plant competition   Money  

摘要： Browsing by herbivores profoundly affects the nature and extent of woody plant communities through a variety of mechanisms, including alterations to disturbance regimes (such as fire frequency), indirect effects on nutrient cycling and soil fertility, and changes to net primary production ( Hobbs 1996). Plants have evolved myriad ways to avoid being eaten, ranging from the development of spiny, unpalatable foliage to the production of secondary metabolites as defense compounds ( Bennett and Wallsgrove 1994). In analyzing the responses of plants to herbivory and the consequences of these responses for plant–plant competition, there has often been an implicit assumption that such defense strategies come at a cost to the individual (more defense means less growth or reproduction), thereby providing the basis for fundamental ecological and evolutionary hypotheses about allocation of limited resources ( Strauss et al. 2002).

关键词： forest regeneration   grasslands   savannah trees   species diversity   woody plants  

摘要： Previous studies suggest that forest regeneration in grasslands is often slow because of grass competition and fire and that regeneration may be dependent on fire-resistant savannah trees. To examine the potential of savannah trees in facilitating regeneration, species diversity, number and total abundance of species of woody plants were determined below and away from Acacia sieberiana and Erythrina abyssinica tree crowns. Additionally, crown size and distance from a natural forest were estimated to determine their influence on natural regeneration. Results showed that the environment under tree crowns positively influence diversity compared to that outside crowns: including for biodiversity (3.08 versus 2.82), the number of species and total abundance (P < 0.001). However, distance from the forest to trees in the grassland had no influence on these parameters. Vertebrate animals were found to be the major seed dispersers in grasslands of Kibale. We concluded that forests that establish below crowns of savannah trees will be more diverse than those in treeless areas and that crown size is more important than distance from natural forest in facilitating regeneration. Furthermore, A. sieberiana could be more suitable in facilitating natural regeneration, while animals have proved to be vital for *** Des etudes anterieures suggerent que la regeneration forestiere dans les prairies est souvent lente en raison de la competition des herbes et des feux et qu'elle peut dependre des arbres de savane qui resistent aux feux. Afin d'examiner le potentiel qu'ont les arbres de savane de faciliter la regeneration, on a determine la diversite en especes, le nombre et l'abondance totale d'especes vegetales ligneuses sous la couronne d'Acacia sieberiana et de Erythrina abyssinica et a une certaine distance. De plus, on a estime la taille de la couronne des arbres et leur distance par rapport a une foret naturelle pour determiner leur influence sur la regeneration natu