辽宁棋盘山森林公园种子植物区系研究

在实地考察和标本采集鉴定的基础上,对辽宁棋盘山森林公园种子植物的组成、分布类型和区系特征进行了分析研究.结果表明,棋盘山森林公园共有种子植物69科187属264种,其中裸子植物4科9属23种,被子植物65科178属241种;植被类型多样,区系地理成分复杂,具有强烈的温带性质;区内具有一定数量的重点保护植物,但特有现象不...     

Biomass transformation webs provide a unified approach to consumer-resource modelling

An approach to modelling food web biomass flows among live and dead compartments within and among species is formulated using metaphysiological principles that characterise population growth in terms of basal metabolism, feeding, senescence and exploitation. This leads to a unified approach to modelling interactions among plants, herbivores, carnivores, scavengers, parasites and their resources. Also, dichotomising sessile miners from mobile gatherers of resources, with relevance to feeding and starvation time scales, suggests a new classification scheme involving 10 primary categories of consumer types. These types, in various combinations, rigorously distinguish scavenger from parasite, herbivory from phytophagy and detritivore from decomposer. Application of the approach to particular consumer-resource interactions is demonstrated, culminating in the construction of an anthrax-centred food web model, with parameters applicable to Etosha National Park, Namibia, where deaths of elephants and zebra from the bacterial pathogen, Bacillus anthracis, provide significant subsidies to jackals, vultures and other scavengers.     

From research to implementation: Nature conservation in the Eastern Rhodopes mountains (Greece and Bulgaria), European Green Belt

Nature conservation should ideally build on the scientific recommendations that are concluded from applied conservation research, as well as on monitoring schemes that evaluate the effectiveness of recommendations. We considered as a case study a system of six protected areas located in the Eastern Rhodopes mountains in the southern part of the European Green Belt (EGB). To investigate nature conservation effectiveness, we reviewed 196 articles from scientific journals and books, eight doctoral and master theses, and 39 scientific reports regarding the Greek (one protected area, 428 km²) and the Bulgarian (five protected areas, 904 km²) part of the study area. We extracted 743 conservation recommendations, and through questionnaires completed by 10 local experts, we found that 74% of the recommendations were familiar for the experts. In the Greek (GR) and the Bulgarian part (BG) only 52% and 16%, respectively, of the recommendations were implemented, and only 15% (GR) and 3.1% (BG) were implemented and evaluated regarding their effectiveness. According to the experts, the main reasons for non-implementation and non-evaluation were absence or incompetence of the responsible authorities. Some recommendations obtained a remarkable low rate of implementation, such as those regarding agriculture and livestock rearing practices (GR: 29%, BG: 16%) or mammal conservation (GR: 0%, BG: 16%). Some other recommendations obtained rather high rates at least for Greece, such as tourism and environmental education (GR: 57%, BG: 42%) and bird conservation (GR: 57%, BG: 11%). We found that researchers and conservation managers at both sides of the Greek-Bulgarian border face similar implementation problems, related often to the lack of political will for nature conservation and establishment of competent authorities. The role of the EGB is crucial in enhancing the established cross-border collaborations between stakeholders involved in nature conservation.     

Intestinal parasites and bacteria of mountain gorillas (Gorilla beringei beringei) in Bwindi Impenetrable National Park, Uganda

A survey in 1994 examined intestinal helminths and bacterial flora of mountain gorillas (Gorilla beringei beringei) in Bwindi Impenetrable National Park, Uganda. Parasites and bacteria were identified to genus in the feces of two groups of tourist-habituated and one group of non-tourist-habituated mountain gorillas. Eggs were identified as those of an anoplocephalid cestode, and nematode eggs representative of the genera: Trichuris, Ascaris, Oesophagostomum, Strongyloides, and Trichostrongylus. This is the first report of Ascaris lumbricoides-like eggs in mountain gorillas. Fecal samples (n=76) from all groups contained helminth eggs, with strongyle eggs and anoplocephalid eggs being the most common. Salmonella and Campylobacter were found in both gorilla groups. Regular long-term non-invasive fecal monitoring of the populations of mountain gorillas is essential for the prevention and identification of potential health threats by intestinal parasites and bacteria in this highly endangered subspecies.This revised version was published online in April 2005 with corrections to the cover date of the issue.     

Flood-deposited wood debris and its contribution to heterogeneity and regeneration in a semi-arid riparian landscape

We investigated whether large woody debris (LWD) piles create nodes of environmental resources that contribute to the recovery of riparian vegetation and that also augment the heterogeneity and resilience of the riverine system. River and riparian systems are typified by a large degree of heterogeneity and complex interactions between abiotic and biotic elements. Disturbance such as floods re-distribute the resources, such as LWD, and thereby add greater complexity to the system. We examined this issue on a semi-arid savanna river where a ~100-year return interval flood in 2000 uprooted vegetation and deposited substantial LWD. We investigated the micro-environment within the newly established LWD piles and compared this with conditions at adjacent reference sites containing no LWD. We found soil nutrient concentrations to be significantly higher in LWD piles compared with the reference plots (total N +19%, available P +51%, and total C +36%). Environmental variables within LWD piles and reference sites varied with landscape position in the river–riparian landscape and with LWD pile characteristics. Observed differences were generally between piles located in the terrestrial and riparian areas as compared to piles located on the macro-channel floor. After 3 years the number and cover of woody species were significantly higher when associated with LWD piles, regardless of landscape position or pile type. We conclude that LWD piles formed after large floods act as resource nodes by accumulating fine sediments and by retaining soil nutrients and soil moisture. The subsequent influence of LWD deposition on riparian heterogeneity is discerned at several spatial scales including within and between LWD piles, across landscape positions and between channel types. LWD piles substantially influence the initial developmental of riparian vegetation as the system regenerates following large destructive floods.     

Effects of body size on the diurnal activity budgets of African browsing ruminants

We compared the diurnal activity budgets of four syntopic species of African browsing ruminant that differ widely in body size. These were concurrently studied through all phases of the seasonal cycle, in the same area, using the same methods. We tested five predictions from the literature on how body size is expected to influence the behaviour of tropical ungulates: the smallest members of the browsing ruminant guild exhibit (1) the lowest allocation of diurnal time to activity; (2) the greatest hour-to-hour variation in activity and resting time; (3) the greatest reduction in activity time during the hottest days; (4) the least change between wet and the dry seasons in the ratio of feeding: ruminating time; and (5) the greatest time budget allocation to vigilance. Prediction 1 was supported in that the smaller species spent less time being active during the day. Prediction 2 was also supported in that the smaller species were more variable in their relative allocations of time to activity and resting through successive hours of the day. Contrary to Prediction 3, however, the greatest reduction in activity with increasing temperature was found for the largest guild member. The smaller species can achieve their daily food intake requirements by feeding at night and in the cool hours of the day, while the larger species have to feed during all hours of the day and are thus more susceptible to thermoregulatory constraints on foraging. Prediction 4 was partially upheld in that the largest species (giraffe) displayed the widest variation in feeding: ruminating time through the seasonal cycle. Prediction 5 was not supported, indicating that multiple factors interact with body size in determining vigilance behaviour.     

Hunter Self-monitoring by the Isoseño-Guaraní in the Bolivian Chaco

Declared in 1995, the 34,400 km² Kaa-Iya del Gran Chaco National Park is the first protected area in South America co-managed by an indigenous organization, the Capitanía del Alto y Bajo Isoso (CABI). In 1997, based on historical occupation by the Isoseño-Guaraní over the past 300 years, CABI formally demanded a 19,000 km² `Tierra Comunitaria de Orígen' (TCO) that adjoins, but does not overlap, the national park. The creation of TCOs and the co-administration of protected areas are elements of decentralization processes in Bolivia, whereby the management of land and natural resources is devolving to departmental and municipal levels of government. This paper examines biodiversity monitoring in the context of a community wildlife management program developed with CABI. Hunter self-monitoring (100–150 hunters per month) combined with monthly activity records for potential hunters (7637 observed hunter-months) permit estimations of total offtakes of subsistence game species for 1996–2003, as well as catch-per-unit-effort over the same time period. These data show considerable fluctuations from year to year and no declining trends that would suggest over-hunting. Monitoring populations of multiple game species can be relatively expensive, even with the voluntary support of hunters, considering data collection and analysis, as well as presentation and discussion through community meetings. At the same time, monitoring does not provide highly accurate assessments of short-term changes in wildlife resources. However, relatively simple participatory methods are important for generating information on long-term trends and for creating a context for community discussion of formal wildlife management.     

Landscape genetics of the blotched tiger salamander (Ambystoma tigrinum melanostictum)

The field of landscape genetics has great potential to identify habitat features that influence population genetic structure. To identify landscape correlates of genetic differentiation in a quantitative fashion, we developed a novel approach using geographical information systems analysis. We present data on blotched tiger salamanders (Ambystoma tigrinum melanostictum) from 10 sites across the northern range of Yellowstone National Park in Montana and Wyoming, USA. We used eight microsatellite loci to analyse population genetic structure. We tested whether landscape variables, including topographical distance, elevation, wetland likelihood, cover type and number of river and stream crossings, were correlated with genetic subdivision (F(ST)). We then compared five hypothetical dispersal routes with a straight-line distance model using two approaches: (i) partial Mantel tests using Akaike's information criterion scores to evaluate model robustness and (ii) the BIOENV procedure, which uses a Spearman rank correlation to determine the combination of environmental variables that best fits the genetic data. Overall, gene flow appears highly restricted among sites, with a global F(ST) of 0.24. While there is a significant isolation-by-distance pattern, incorporating landscape variables substantially improved the fit of the model (from an r2 of 0.3 to 0.8) explaining genetic differentiation. It appears that gene flow follows a straight-line topographic route, with river crossings and open shrub habitat correlated with lower F(ST) and thus, decreased differentiation, while distance and elevation difference appear to increase differentiation. This study demonstrates a general approach that can be used to determine the influence of landscape variables on population genetic structure.     

史氏鲟两种促性腺激素β亚基cDNA克隆及序列进化分析

从史氏鲟(Acipenserschrenkii)脑垂体中提取总RNA,利用GeneRacerTM技术,分别克隆得到促性腺激素Ⅰ(GTHⅠ)和Ⅱ(GTHⅡ)的β亚基cDNA全长。史氏鲟GTHⅠ-β亚基cDNA全长为1088bp,开放阅读框为384bp,编码128个氨基酸(Genbank序列登录号为:AY575920);GTHⅡ-β亚基cDNA全长为616bp,开放阅读框为408bp,编码136个氨基酸(Genbank序列登录号为:AY575921)。与其他脊椎动物进行了两种基因的氨基酸序列同源性比较表明:史氏鲟GTHⅠ-β与西伯利亚鲟相似性最高,为99·1%;与硬骨鱼类中鲈形目相似性最低,为34·5%。GTHⅡ-β与西伯利亚鲟相似性为98·3%,与其他硬骨鱼类除鲈形目外都超过60%,与鸟类的相似性最低,为42·8%。两个基因成熟肽构建的MP树显示:GTHⅠ与FSH的β亚基和GTHⅡ与LH的β亚基构成两个明显的聚类。用Mega2软件计算了所比对物种间开放读码框的核苷酸遗传距离并构建了NJ树和MP树,两个基因β亚基的NJ系统树和MP系统树拓扑结构相似,鲟鱼与真骨鱼类分别聚类,共同形成硬骨鱼纲聚类,与传统分类学一致。成熟肽相似性、遗传距离和系统树分支长度显示GTHⅠ-β亚基在真骨鱼类进化速率显著快于其他脊椎动物,而LH-β亚基在羊膜动物中进化比其他脊椎动物快。暗示这两种糖蛋白基因的进化伴随物种进化而显示其功能[动物学报52(2):362-375,2006]。