Exploiting opportunistic observations to estimate changes in seasonal site use: An example with wetland birds

Nonsystematically collected, a.k.a. opportunistic, species observations are accumulating at a high rate in biodiversity databases. Occupancy models have arisen as the main tool to reduce effects of limited knowledge about effort in analyses of opportunistic data. These models are generally using long closure periods (e.g., breeding season) for the estimation of probability of detection and occurrence. Here, we use the fact that multiple opportunistic observations in biodiversity databases may be available even within days (e.g., at popular birding localities) to reduce the closure period to 1 day in order to estimate daily occupancies within the breeding season. We use a hierarchical dynamic occupancy model for daily visits to analyze opportunistic observations of 71 species from nine wetlands during 10 years. Our model derives measures of seasonal site use within seasons from estimates of daily occupancy. Comparing results from our “seasonal site use model” to results from a traditional annual occupancy model (using a closure criterion of 2 months or more) showed that our model provides more detailed biologically relevant information. For example, when the aim is to analyze occurrences of breeding species, an annual occupancy model will over‐estimate site use of species with temporary occurrences (e.g., migrants passing by, single itinerary prospecting individuals) as even a single observation during the closure period will be viewed as an occupancy. Alternatively, our model produces estimates of the extent to which sites are actually used. Model validation based on simulated data confirmed that our model is robust to changes and variability in sampling effort and species detectability. We conclude that more information can be gained from opportunistic data with multiple replicates (e.g., several reports per day almost every day) by reducing the time window of the closure criterion to acquire estimates of occupancies within seasons.     

Methods to identify the prey of invertebrate predators in terrestrial field studies

Predation is an interaction during which an organism kills and feeds on another organism. Past and current interest in studying predation in terrestrial habitats has yielded a number of methods to assess invertebrate predation events in terrestrial ecosystems. We provide a decision tree to select appropriate methods for individual studies. For each method, we then present a short introduction, key examples for applications, advantages and disadvantages, and an outlook to future refinements. Video and, to a lesser extent, live observations are recommended in studies that address behavioral aspects of predator–prey interactions or focus on per capita predation rates. Cage studies are only appropriate for small predator species, but often suffer from a bias via cage effects. The use of prey baits or analyses of prey remains are cheaper than other methods and have the potential to provide per capita predation estimates. These advantages often come at the cost of low taxonomic specificity. Molecular methods provide reliable estimates at a fine level of taxonomic resolution and are free of observer bias for predator species of any size. However, the current PCR‐based methods lack the ability to estimate predation rates for individual predators and are more expensive than other methods. Molecular and stable isotope analyses are best suited to address systems that include a range of predator and prey species. Our review of methods strongly suggests that while in many cases individual methods are sufficient to study specific questions, combinations of methods hold a high potential to provide more holistic insights into predation events. This review presents an overview of methods to researchers that are new to the field or to particular aspects of predation ecology and provides recommendations toward the subset of suitable methods to identify the prey of invertebrate predators in terrestrial field research.     

小鼠腹腔巨噬细胞吞噬功能的扫描电镜观察

本实验利用扫描电镜观察小鼠腹腔巨噬细胞在体外吞噬鸡红血球过程大致可分为巨噬细胞接触、扑获、包绕鸡红血球和鸡红血球在巨噬细胞中内移等4个阶段。经厌氧小棒状杆菌处理的巨噬细胞呈现激活状态,比未经厌氧小棒状杆菌处理的巨噬细胞表现更大的膜活性,胞体铺展增大,突起多呈叶状或皱褶状,吞噬鸡红血球能力明显增强。经厌氧小棒状杆菌处理的巨噬细胞与U27癌细胞存在着接触,此时U27癌细胞易发生变性、坏死。     

龋坏引起的慢性牙髓炎牙髓组织中的细菌超微观察

对１０例龋坏引起的慢性牙髓炎、未穿髓的新鲜离体患牙,进行分段定位、半薄切片、革兰氏染色,光镜观察定位后,再行超薄切片,醋酸铀－柠檬酸铅复染,电镜进行超微结构观察。结果：（１）患牙牙髓组织中有５例观察到多种类型微生物存在,为球杆菌、球菌、杆菌。（２）牙髓组织中的细菌位于细胞内及细胞外,并处于各种状态,有生长繁殖阶段的也有固缩溶解阶段的。（３）深龋引起的长期有症状的慢性牙髓炎牙髓组织中有大量活细菌存在,细菌均存在于冠髓内,接近龋坏部位,周围及深层组织中未见菌体。并观察到组织细胞吞噬大量细菌后,细胞变性,出现核固缩、核仁消失,细胞膜不清楚。细胞周围有大量溶酶体出现。结果提示：深龋引起的长期有症状的慢性牙髓炎,尽管未穿髓,牙髓组织中,仍可有大量活细菌长期存在。     

Partly decoupled tree-ring width and leaf phenology response to 20th century temperature change in Sweden

The recent warming trend, and associated shifts in growing season length, challenge the principle of uniformitarianism, i.e., that current relations are persistent over time, and complicates the uncritical inferences of past climate from tree-ring data. Here we conduct a comparison between tree-ring width chronologies of Pinus sylvestris L. (Scots pine), Picea abies (L.) Karst. (Norway spruce) and Betula pubescens Ehrh. (Downy birch) and phenological observations (budburst and leaf senescence) of Fagus sylvatica L. (European beech), Quercus robur L. (European oak), Betula sp. (Birch), Norway spruce and Scots pine) in Sweden to assess to what extent the tree-ring width–temperature relationship and the timing of phenological phases are affected by increased temperature. Daily meteorological observations confirm a prolongation of the thermal growing season, most consistently observed as an earlier onset of around 1–2 weeks since the beginning of the 20th century. Observations of budburst closely mimic this pattern, with budburst of the deciduous trees occurring 1–2.5 weeks earlier. In contrast to the changes seen in phenology and observational temperature data, the tree-ring width–temperature relationships remain surprisingly stable throughout the 20th century. Norway spruce, Scots pine and Downy birch all show consistently significant correlations with at least one 30 day-long window of temperature starting in late June–early July season. Norway spruce displays the largest degree of stability, with a consistent 60 day-long temperature window with significant correlation starting around Julian calendar day 150. Thus, our results suggest that the principle of uniformitarianism is not violated during the period covered by modern meteorological observations. Further research is needed to determine at what thresholds the temperature sensitivity of these species may alter or deteriorate as a consequence of the ongoing climate change.     

沈阳城市森林主要树种物候对气候变暖的响应

采用统计和线性回归方法,探讨了近40年来沈阳城市森林主要树种物候对气候变暖的响应.结果表明,沈阳城市森林树木休眠期长短与冬季气温密切相关,适宜的寒冷条件有利于解除树木休眠期;树木萌动期早晚与冬季和早春气温高低呈显著的负相关关系,冬春季气温越高,芽萌动越提前.树木爆芽后15 d左右开始展叶,展叶早晚主要受展叶前的春季气温高低的影响,但与冬季气温没有相关关系.始花前2～8旬,特别是2～4旬气温对始花期影响最显著,春季气温升高始花期提前. 树木芽萌动期、展叶始期与寒冷指数（CI）呈显著正相关关系,而开花始期与CI没有相关关系.沈阳城市森林树木对气候变暖的响应,主要表现在年均温升高1 ℃,芽萌动期提前9 d,展叶始期提前10 d,开花始期提前5 d.     

Prediction errors for state occupation and transition probabilities in multi‐state models

In this paper, we consider the estimation of prediction errors for state occupation probabilities and transition probabilities for multistate time‐to‐event data. We study prediction errors based on the Brier score and on the Kullback–Leibler score and prove their properness. In the presence of right‐censored data, two classes of estimators, based on inverse probability weighting and pseudo‐values, respectively, are proposed, and consistency properties of the proposed estimators are investigated. The second part of the paper is devoted to the estimation of dynamic prediction errors for state occupation probabilities for multistate models, conditional on being alive, and for transition probabilities. Cross‐validated versions are proposed. Our methods are illustrated on the CSL1 randomized clinical trial comparing prednisone versus placebo for liver cirrhosis patients.     

Phase shifts and the role of herbivory in the resilience of coral reefs

Cousin Island marine reserve (Seychelles) has been an effectively protected no-take marine protected area (MPA) since 1968 and was shown in 1994 to support a healthy herbivorous fish assemblage. In 1998 Cousin Island reefs suffered extensive coral mortality following a coral bleaching event, and a phase shift from coral to algal dominance ensued. By 2005 mean coral cover was <1%, structural complexity had fallen and there had been a substantial increase in macroalgal cover, up to 40% in some areas. No clear trends were apparent in the overall numerical abundance and biomass of herbivorous fishes between 1994 and 2005, although smaller individuals became relatively scarce, most likely due to the loss of reef structure. Analysis of the feeding habits of six abundant and representative herbivorous fish species around Cousin Island in 2006 demonstrated that epilithic algae were the preferred food resource of all species and that macroalgae were avoided. Given the current dominance of macroalgae and the apparent absence of macroalgal consumers, it is suggested that the increasing abundance of macroalgae is reducing the probability of the system reverting to a coral dominated state.     

丛栽茶树树冠小气候及其对新梢生育和生化成分的影响

1 引言 为了获得优质高产的茶叶,需通过修剪养蓬等方法,使茶树形成宽广而整齐的树冠。丛栽茶树的树冠多呈馒头形,由于方位不同,形成了树冠内光、温、湿、风等因子的差异,因而影响了茶树的物候期及生理生化变化。因此,探讨树冠小气候特征及其对茶树新梢生育和生化成分的影响,在理论和生产实践上均有意义。有关这方面研究已有一些报道,但对茶树树冠小气候特征及其茶树新梢生育和品质成分的影响尚未见报     

Life-history pathways in relation to gonadal sex differentiation in the anemonefish,Amphiprion clarkii,in temperate waters of Japan

Synopsis The process of gonadal sex differentiation in Amphiprion clarkii was investigated for 2 years at Murote Beach, Shikoku Island, Japan. Six color phases were discriminated on the basis of the caudal fin coloration, which corresponded well to six gonadal phases. From changes of the color phases with growth, three life history pathways were detected: (1) subadult male subadult female adult female, (2) subadult male adult male adult female, (3) subadult male adult male. Different pathways were due to the difference of timing among individuals in the development of ovarian tissues of the hermaphroditic gonads involving the atrophy of testicular tissues. Irreversible differentiation of ovarian tissues of the gonads occurred more frequently among nonbreeders (10 cases) than among breeders (4 cases). The second pathway, which has been thought the norm of tropical anemonefishes, was therefore not primary in this population. This can be attributed to ecological conditions: fish are able to move between host sea anemones and nonbreeders can escape from social suppression by adult pairs because of high population density of hosts.