仁化县野生白毛茶群落特征及保护对策

以广东仁化县董塘镇及红山镇5个分布有野生白毛茶Camellia sinensis var. pubilimba的生存群落为对象,开展样方调查及群落生态学分析,以期明确野生白毛茶的生长状况及保护对策。结果表明：(1) 5个有野生白毛茶分布的群落,共分布有维管植物177种,隶属于63科119属,其中蕨类植物13科17属21种,被子植物49科101属155种;(2) 白毛茶野生种群分布于毛竹Phyllostachys heterocycla、杉木Cunninghamia lanceolata群落演替而成的次生林,群落上层以毛竹、杉木、华润楠Machilus chinensis、罗浮柿Diospyros morrisiana为优势种,灌木层以白毛茶、红背山麻杆Alchornea trewioides、绒毛山胡椒Lindera nacusua、八角枫Alangium chinense为优势种,草本层以乌毛蕨Blechnum orientale、蔓生莠竹Microstegium fasciculatum、三叶崖爬藤Tetrastigma hemsleyanum等占优势;(3) 除次生林外,其余群落中草本层Simpson指数、Shannon-wiener指数及均匀度均高于乔木层及灌木层,这可能是自然演替进程与人类砍伐活动综合作用的结果;(4) 野生白毛茶更适合处于中度干扰的次生林中,较为湿润的阳坡利于其发展;(5) 野生白毛茶数量虽多,共258株,却均为小苗,且生长状况并不理想,需及时采取有效的保护措施就地保护、适度干扰,同时加强民众教育保护现有野生资源,扩大野生种群调查范围,兼顾回归实验。     

Field estimates of fitness costs of the pace‐of‐life in an endangered damselfly

Theory predicts that within‐population differences in the pace‐of‐life can lead to cohort splitting and produce marked intraspecific variation in body size. Although many studies showed that body size is positively correlated with fitness, many argue that selection for the larger body is counterbalanced by opposing physiological and ecological selective mechanisms that favour smaller body. When a population split into cohorts with different paces of life (slow or fast cohort), one would expect to detect the fitness–size relationship among and within cohorts, that is, (a) slower‐developing cohort has larger body size and higher fitness than faster‐developing cohort, and (b) larger individuals within each cohort show higher fitness than smaller individuals. Here, we test these hypotheses in capture–mark–recapture field surveys that assess body size, lifespan, survival and lifetime mating success in two consecutive generations of a partially bivoltine aquatic insect, Coenagrion mercuriale, where the spring cohort is slower‐developing than the autumn cohort. As expected, body size was larger in the slow‐developing cohort, which is consistent with the temperature‐size rule and also with the duration of development. Body size seasonal variation was greater in slow‐developing cohort most likely because of the higher variation in age at maturity. Concordant with theory, survival probability, lifespan and lifetime mating success were higher in the slow‐developing cohort. Moreover, individual body size was positively correlated with survival and mating success in both cohorts. Our study confirms the fitness costs of fast pace‐of‐life and the benefits of larger body size to adult fitness.     

Long-term survival of patients with prostate cancer in Martinique: Results of a population-based study

BackgroundMartinique has one of the highest incidences of prostate cancer (PCa) worldwide. We analysed overall survival (OS) among patients with PCa in Martinique, using data from a population-based cancer registry between 2005 and 2014.MethodsThe log-rank test was used to assess the statistical differences between survival curves according to age at diagnosis, risk of disease progression including Gleason score, stage at diagnosis and Prostate Specific Antigen (PSA). A multivariable Cox model was constructed to identify independent prognostic factors for OS.ResultsA total of 5045 patients were included with a mean age at diagnosis of 68.1±9.0 years [36.0 – 98.0 years]. Clinical stage was analysed in 4999 (99.1% of overall), 19.5% were at low risk, 34.7% intermediate and 36.9% at high risk. In our study, 8.9% of patients with available stage at diagnosis, were regional/metastatic cancers. Median PSA level at diagnosis was 10.4 ng/mL. High-risk PCa was more frequent in patients aged 65-74 and ≥75 years as compared to those aged <65 years (36.6% and 48.8% versus 28.7% respectively; p<0.0001). One-year OS was 96.3%, 5-year OS was 83.4 and 10-year OS was 65.0%. Median survival was not reached in the whole cohort. High-risk PCa (HR=2.32; p<0.0001), regional/metastatic stage (HR= 9.51; p<0.0001) and older age (65-74 and ≥75 years - respectively HR=1.70; and HR=3.38), were independent prognostic factors for OS (p<0.0001).ConclusionThis study provides long term data that may be useful in making cancer management decisions for patients with PCa in Martinique.     

Differential plague susceptibility in species and populations of prairie dogs

Laboratory trials conducted over the past decade at U.S. Geological Survey National Wildlife Health Center indicate that wild populations of prairie dogs (Cynomys spp.) display different degrees of susceptibility to experimental challenge with fully virulent Yersinia pestis, the causative agent of plague. We evaluated patterns in prairie dog susceptibility to plague to determine whether the historical occurrence of plague at location of capture was related to survival times of prairie dogs challenged with Y. pestis. We found that black‐tailed prairie dogs (Cynomys ludovicianus) from South Dakota (captured prior to the detection of plague in the state), Gunnison's prairie dogs (Cynomys gunnisoni) from Colorado, and Utah prairie dogs (Cynomys parvidens) from Utah were most susceptible to plague. Though the susceptibility of black‐tailed prairie dogs in South Dakota compared with western locations supports our hypothesis regarding historical exposure, both Colorado and Utah prairie dogs have a long history of exposure to plague. It is possible that for these populations, genetic isolation/bottle necks have made them more susceptible to plague outbreaks.     

Life‐history differences across latitude in common side‐blotched lizards (Uta stansburiana)

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Estimability of migration survival rates from integrated breeding and winter capture–recapture data

Long‐distance migration is a common phenomenon across the animal kingdom but the scale of annual migratory movements has made it difficult for researchers to estimate survival rates during these periods of the annual cycle. Estimating migration survival is particularly challenging for small‐bodied species that cannot carry satellite tags, a group that includes the vast majority of migratory species. When capture–recapture data are available for linked breeding and non‐breeding populations, estimation of overall migration survival is possible but current methods do not allow separate estimation of spring and autumn survival rates. Recent development of a Bayesian integrated survival model has provided a method to separately estimate the latent spring and autumn survival rates using capture–recapture data, though the accuracy and precision of these estimates has not been formally tested. Here, I used simulated data to explore the estimability of migration survival rates using this model. Under a variety of biologically realistic scenarios, I demonstrate that spring and autumn migration survival can be estimated from the integrated survival model, though estimates are biased toward the overall migration survival probability. The direction and magnitude of this bias are influenced by the relative difference in spring and autumn survival rates as well as the degree of annual variation in these rates. The inclusion of covariates can improve the model's performance, especially when annual variation in migration survival rates is low. Migration survival rates can be estimated from relatively short time series (4–5 years), but bias and precision of estimates are improved when longer time series (10–12 years) are available. The ability to estimate seasonal survival rates of small, migratory organisms opens the door to advancing our understanding of the ecology and conservation of these species. Application of this method will enable researchers to better understand when mortality occurs across the annual cycle and how the migratory periods contribute to population dynamics. Integrating summer and winter capture data requires knowledge of the migratory connectivity of sampled populations and therefore efforts to simultaneously collect both survival and tracking data should be a high priority, especially for species of conservation concern.     

“Closer‐to‐home” strategy benefits juvenile survival in a long‐distance migratory bird

Human‐induced changes in the climate and environment that occur at an unprecedented speed are challenging the existence of migratory species. Faced with these new challenges, species with diverse and flexible migratory behaviors may suffer less from population decline, as they may be better at responding to these changes by altering their migratory behavior. At the individual level, variations in migratory behavior may lead to differences in fitness and subsequently influence the population's demographic dynamics. Using lifetime GPS bio‐logging data from 169 white storks (Ciconia ciconia), we explore whether the recently shortened migration distance of storks affects their survival during different stages of their juvenile life. We also explore how other variations in migratory decisions (i.e., time, destination), movement activity (measured using overall body dynamic acceleration), and early life conditions influence juvenile survival. We observed that their first autumn migration was the riskiest period for juvenile white storks. Individuals that migrated shorter distances and fledged earlier experienced lower mortality risks. In addition, higher movement activity and overwintering “closer‐to‐home” (with 84.21% of the tracked individuals stayed Europe or North Africa) were associated with higher survival. Our study shows how avian migrants can change life history decisions over only a few decades, and thus it helps us to understand and predict how migrants respond to the rapidly changing world.     

Early emergence increases survival of tree seedlings in Central European temperate forests despite severe late frost

Global warming is expected to result in earlier emergence of tree seedlings that may experience higher damages and mortality due to late frost in spring. We monitored emergence, characteristics, and survival of seedlings across ten tree species in temperate mixed deciduous forests of Central Europe over one and a half year. We tested whether the timing of emergence represents a trade‐off for seedling survival between minimizing frost risk and maximizing the length of the growing period. Almost two‐thirds of the seedlings died during the first growing period. The timing of emergence was decisive for seedling survival. Although seedlings that emerged early faced a severe late frost event, they benefited from a longer growing period resulting in increased overall survival. Larger seedling height and higher number of leaves positively influenced survival. Seedlings growing on moss had higher survival compared to mineral soil, litter, or herbaceous vegetation. Synthesis. Our findings demonstrate the importance of emergence time for survival of tree seedlings, with early‐emerging seedlings more likely surviving the first growing period.     

Female reproduction bears no survival cost in captivity for gray mouse lemurs

The survival cost of reproduction has been revealed in many free‐ranging vertebrates. However, recent studies on captive populations failed to detect this cost. Theoretically, this lack of survival/reproduction trade‐off is expected when resources are not limiting, but these studies may have failed to detect the cost, as they may not have fully accounted for potential confounding effects, in particular interindividual heterogeneity. Here, we investigated the effects of current and past reproductive effort on later survival in captive females of a small primate, the gray mouse lemur. Survival analyses showed no cost of reproduction in females; and the pattern was even in the opposite direction: the higher the reproductive effort, the higher the chances of survival until the next reproductive event. These conclusions hold even while accounting for interindividual heterogeneity. In agreement with aforementioned studies on captive vertebrates, these results remind us that reproduction is expected to be traded against body maintenance and the survival prospect only when resources are so limiting that they induce an allocation trade‐off. Thus, the cost of reproduction has a major extrinsic component driven by environmental conditions.     

Colorectal cancer and country of birth in New South Wales,Australia: All-of-population data for prioritising health service delivery and research

IntroductionCancer care and outcomes differ across cultural groups in Australia. Quantifying these differences facilitates prioritisation and targeting of services and research. All-of-population data are needed by health agencies to understand and fulfil their cancer-control responsibilities. Compiling these data can be challenging while maintaining privacy. We have used data linkage to gain population-wide colorectal cancer data on stage (degree of spread), treatment, and survival in New South Wales (NSW), Australia, by country of birth (COB), and consider service implications.MethodsWe studied colon and rectal cancers diagnosed in 2003–2016 and recorded on the NSW Cancer Registry (n = 41,575), plus linked hospital data and data from Australian Medical and Pharmaceutical Benefits payments, other treatment data and death records. Outcomes for 12 COB categories were analysed using multiple logistic and proportional hazards regression, with Australia as the reference category.ResultsCompared with Australian born, the adjusted odds ratio for distant spread of colon cancer was higher for people born in Lebanon and the United Kingdom. Treatment was less common for people born in China (surgery), Germany (systemic), Italy (surgery), New Zealand (any treatment) and Vietnam (all treatments), while treatment for rectal cancer was more common for people born in Italy (surgery), United Kingdom (radiotherapy, systemic therapy), and Vietnam (surgery), and less frequent for people born in China (radiotherapy). Adjusted 5-year survival was higher for people born in China, Italy, Vietnam, Greece (colon), Lebanon (colon) and other non-English speaking countries. More advanced stage was negatively related to having surgery and survival.ConclusionsThis study illustrates how linked data can enable comparisons of multiple outcomes for colorectal cancer by country of birth across an entire population. Results disclose “big picture” variations in population characteristics, stage, treatment and survival. This will enable better targeting and prioritisation of services and inform research priorities to address disparities.