Multilocus estimation of selfing and its heritability

We describe a new method of estimating the selfing rate (S) in a mixed mating population based on a population structure approach that accounts for possible intergenerational correlation in selfing rate, giving rise to an estimate of the upper limit for heritability of selfing rate (h(2)). A correlation between generations in selfing rate is shown to affect one- and two-locus probabilities of identity by descent. Conventional estimates of selfing rate based on a population structure approach are positively biased by intergenerational correlation in selfing. Multilocus genotypes of individuals are used to give maximum-likelihood estimates of S and h(2) in the presence of scoring artifacts. Our multilocus estimation of selfing rate and its heritability (MESH) method was tested with simulated data for a range of conditions. Selfing rate estimates from MESH have low bias and root mean squared error, whereas estimates of the heritability of selfing rate have more uncertainty. Increasing the number of individuals in a sample helps to reduce bias and root mean squared error more than increasing the number of loci of sampled individuals. Improved estimates of selfing rate, as well as estimates of its heritability, can be obtained with this method, although a large number of loci and individuals are needed to achieve best results.     

The effects of thinning and gypsy moth defoliation on wood volume growth in oaks

Stem dissection and dendroecological methods were used to examine the effects of thinning and defoliation by gypsy moth (Lymantria dispar L.) on wood volume increment in oaks (Quercus rubra L., Q. alba L., Q. prinus L.). A model was developed to evaluate radial volume increment growth at three time periods: before defoliation, during defoliation and after defoliation, as a function of species, defoliation intensity and crown position. Volume increment during these same time periods was also compared at different stem locations. Trees were defoliated for two consecutive years and results indicated that volume loss was greater during the second year of defoliation with complete recovery taking 2–3 years after defoliation. Oaks in thinned stands had similar reductions in annual volume increment during defoliation as those in the unthinned stand. Annual volume increment demonstrated a decreasing trend from stump to base of the live crown and volume increment of the lowest log (from stump height to 1.37 m), was always higher than upper log sections, even during defoliation. Both earlywood and latewood increments were reduced during defoliation; however, latewood reductions were distributed along entire stems while earlywood reductions were greater on upper stem sections within the crown.     

A signed-rank test for clustered data

Summary .   We consider the problem of comparing two outcome measures when the pairs are clustered. Using the general principle of within-cluster resampling, we obtain a novel signed-rank test for clustered paired data. We show by a simple informative cluster size simulation model that only our test maintains the correct size under a null hypothesis of marginal symmetry compared to four other existing signed rank tests; further, our test has adequate power when cluster size is noninformative. In general, cluster size is informative if the distribution of pair-wise differences within a cluster depends on the cluster size. An application of our method to testing radiation toxicity trend is presented.     

洞庭湖流域麋鹿等哺乳动物濒危灭绝原因的分析及其对麋鹿重引入的启示

洞庭湖流域曾有亚洲象(Elephasmaximus)、犀(Rhinocerossp.)、麋鹿(Elaphurusdavidianus)、川金丝猴(Rhinopithecusroxellana)、长臂猿(Hylobatessp.)、大熊猫(Ailuropodamelanoleuca)、梅花鹿(Cervusnippon)、棕熊(Ursusarctos)等哺乳动物分布,但受古气候、古地理以及人类活动的影响,这些哺乳动物已在洞庭湖流域灭绝。这些哺乳动物的濒危和灭绝既受自然环境变化和灾变的影响,也与物种本身生物学特性和人类活动有关,尤其与人类捕杀和生境丧失有关。据古籍记载分析:在洞庭湖流域,亚洲象和犀于北宋末期灭绝或已南迁,而野生麋鹿、大熊猫、川金丝猴、长臂猿、梅花鹿和棕熊等于19世纪末灭绝。根据我们对30个自然保护区或森林公园野生动物资源实地调查的结果,在洞庭湖流域已记录到21种国家重点保护哺乳动物,其中有5、6、10种哺乳动物分别处于“极危”、“濒危”、“易危”等级,这表明物种濒危的过程仍在继续。导致这些现生哺乳动物濒危的主要原因是生境丧失、人类猎捕、环境污染等,而人类活动干扰对现生濒危物种存活的影响越来越大。洞庭湖流域重引入麋鹿需采取人类协助生存策略:提供足够的且受洪水影响小的适宜生境、保证稳定的奠基者种群数量、减少人为干扰、调控种群密度、实施社区共管和生计替代项目、加强疾病防治、完善保护措施、加大保护基金投入、加强生境监测和湿地恢复等。     

Recruitment and growth of herb‐layer species with different colonizing capacities in ancient and recent forests

Abstract. Forest herbs differ greatly in their capacity to recolonize secondary forests established on former agricultural land. We investigated whether interspecific differences in recruitment or growth can account for differences in colonization success. Seeds and adults of two species with limited colonization capacities (Anemone nemorosa and Primula elatior) and two species with high colonization capacities (Ranunculus ficaria and Geum urbanum) were introduced in ancient and recent forest sites within the Muizen forest (Belgium). At all sites, half of the plots were also cleared of above‐ground vegetation. Seedling establishment was similar in recent and ancient forest sites. However, both the number and subsequent survival of seedlings of the two hemicryptophytes (G. urbanum and P. elatior) were significantly lower when vegetation cover was present, while seedling number and survival of the two geophytes (A. nemorosa and R. ficaria) were less influenced by vegetation cover. Adult performance of P. elatior and G. urbanum was significantly better in the nutrient enriched recent forest stands and in the absence of vegetation cover. Performance of A. nemorosa and R. ficaria was not affected by any of these factors. We conclude that the extent of seed limitation is probably the main cause for the different colonization capacities of the species investigated.     

Invasion in space and time: non-native species richness and relative abundance respond to interannual variation in productivity and diversity

Ecologists have long sought to understand the relationships among species diversity, community productivity and invasion by non‐native species. Here, four long‐term observational datasets were analyzed using repeated measures statistics to determine how plant species richness and community resource capture (i.e. productivity) influenced invasion. Multiple factors influenced the results, including the metric used to quantify invasion, interannual variation and spatial scale. Native richness was positively correlated with non‐native richness, but was usually negatively correlated with non‐native abundance, and these patterns were stronger at the larger spatial scale. Logistic regressions indicated that the probability of invasion was reduced both within and following years with high productivity, except at the desert grassland site where high productivity was associated with increased invasion. Our analysis suggests that while non‐natives were most likely to establish in species rich communities, their success was diminished by high resource capture by the resident community.     

论《卡塔赫纳生物安全议定书》中与WTO规则冲突的贸易措施

本文介绍了《卡塔赫纳生物安全议定书》的贸易措施 ,以及其与《实施卫生和植物卫生措施协定》、《技术贸易壁垒协定》以及GATT1994等WTO规则的冲突 ,进而指出协调冲突的法律原则和我国的因应之策。     

70年代以来柑桔灾害性天气综述及防御措施

20世纪 70年代以来 ,我国柑桔 (Ｃｉｔｒｓｒｅｔｉｃｕｌａｔａ)生产有了迅速增长 ,但由于全球气候的变化 ,出现不利于柑桔生长的灾害性天气 ,并有愈演愈烈的趋势 ,给柑桔生产带来了极大的影响。弄清灾害性天气的发生及规律 ,并提出其防御措施 ,对于进一步科学指导柑桔生产 ,完善柑桔与生境的理论 ,都有一定的现实意义。1　灾害性天气1.1　周期性大冻害据统计 ,公元 14 5 0 - 1979年的 5 2 9年中共出现了 79个严重冻害年 ,平均 10年中有 1.5次。从顺昌县及福建省的气象资料看出 ,约 9～ 10年有 1次周期性的大冻害 ,并在福建省几个县市均有…     

Selecting agri-environmental indicators for monitoring and assessment of environmental management in the example of landscape parks in Poland

The objective of this article is to assess the condition of and hazards to the natural environment in selected landscape parks in Poland with respect to the impact of agricultural management using the DPSIR method. Our proposed set of indicators, based on generally available and applicable data, shows at the local scale, in a simple way, the condition of functioning of the balance between the natural environment and agricultural management and it assesses the level of repair works in the context of the records of the environmental protection program. The highest negative impact of agricultural management in the areas studied is noticed in the soil environment as well as the contexts of biodiversity and landscape. On the other hand, the lowest influence of agricultural economy was noted in the cases of the atmosphere and hydrosphere. The results of the aggregated indicators also showed lower or higher dependencies between the coverage and the use of the area in landscape parks and the condition of particular elements of the environment and the landscape.     

Species Management Benchmarking: Outcomes Over Outputs in a Changing Operating Environment

Species management has been utilized by the zoo and aquarium industry, since the mid‐1990s, to ensure the ongoing genetic and demographic viability of populations, which can be difficult to maintain in the ever‐changing operating environments of zoos. In 2009, the Zoo and Aquarium Association Australasia reviewed their species management services, focusing on addressing issues that had arisen as a result of the managed programs maturing and operating environments evolving. In summary, the project examined resourcing, policies, processes, and species to be managed. As a result, a benchmarking tool was developed (Health Check Report, HCR), which evaluated the programs against a set of broad criteria. A comparison of managed programs (n = 98), between 2008 and 2011, was undertaken to ascertain the tool's effectiveness. There was a marked decrease in programs that were designated as weak (37 down to 13); and an increase in excellent programs (24 up to 49) between the 2 years. Further, there were significant improvements in the administration benchmarking area (submission of reports, captive management plan development) across a number of taxon advisory groups. This HCR comparison showed that a benchmarking tool enables a program's performance to be quickly assessed and any remedial measures applied. The increases observed in program health were mainly due to increased management goals being attained. The HCR will be an ongoing program, as the management of the programs increases and goals are achieved, criteria will be refined to better highlight ongoing issues and ways in which these can be resolved. Zoo Biol. 32:230–237, 2013. © 2012 Wiley Periodicals, Inc.