A novel,easy method for estimating pheromone trap attraction range: application to the pine sawyer beetle Monochamus galloprovincialis

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The importance of growing up: juvenile environment influences dispersal of individuals and their neighbours

Dispersal is a key ecological process that is strongly influenced by both phenotype and environment. Here, we show that juvenile environment influences dispersal not only by shaping individual phenotypes, but also by changing the phenotypes of neighbouring conspecifics, which influence how individuals disperse. We used a model system (Tribolium castaneum, red flour beetles) to test how the past environment of dispersing individuals and their neighbours influences how they disperse in their current environment. We found that individuals dispersed especially far when exposed to a poor environment as adults if their phenotype, or even one‐third of their neighbours’ phenotypes, were shaped by a poor environment as juveniles. Juvenile environment therefore shapes dispersal both directly, by influencing phenotype, as well as indirectly, by influencing the external social environment. Thus, the juvenile environment of even a minority of individuals in a group can influence the dispersal of the entire group.     

Biomass,carbon density and diversity of tree species in tropical dry deciduous forests in Central India

Tropical dry deciduous forests play a significant role in regulating the biogeochemical cycles. Present study assesses the carbon stock of tropical dry deciduous forests varying in tree density, basal cover, and diversity located in Singrauli district of Madhya Pradesh in Central India. Field sampling was carried out in six forest sites viz., Chitrangi, East Sarai, Gorbi, Renukoot, West Sarai, and Waidhan, of Singrauli. A total of 29 tree species belonging to 18 families were recorded across the forest ranges where tree density, basal area and diversity values varied from 702 (Gorbhi Range) – 1671 (East Sarai range) individuals ha^?1; 15.43 (Renukhund range) – 71.76 m² ha^?1 (Chitrange range) and 0.69 (West Sarai range) – 2.52 (Gorbi range), respectively. Total biomass estimated ranged from 103.32 (Renukhund range) – 453.54 Mg ha^?1 (Chitrange range) while the total tree carbon density varied from 48.97 to 214.97 Mg C ha^?1. The variation in carbon storage in the studied ranges was found dependent on density of trees in different diameter and age classes and tree species diversity. Diospyros melanoxylon, Butea monosperma, Shorea robusta, Senegalia catechu, Spondias pinnata, and Lagerstroemia parviflora were the dominant species at different study sites (forest ranges) and contributed towards higher carbon storage in respective forest ranges. Study endorses field-based approach for carbon estimations based on above and belowground assessments as a more realistic approach to understand sink potential of natural forests.     

Seasonal climate effects on the survival of a hibernating mammal

Global climate change and associated regional climate variability is impacting the phenology of many species, ultimately altering individual fitness and population dynamics. Yet, few studies have considered the effects of pertinent seasonal climate variability on phenology and fitness. Hibernators may be particularly susceptible to changes in seasonal climate since they have a relatively short active season in which to reproduce and gain enough mass to survive the following winter. To understand whether and how seasonal climate variability may be affecting hibernator fitness, we estimated survival from historical (1964–1968) and contemporary (2014–2017) mark–recapture data collected from the same population of Uinta ground squirrels (UGS, Urocitellus armatus), a hibernator endemic to the western United States. Despite a locally warming climate, the phenology of UGS did not change over time, yet season‐specific climate variables were important in regulating survival rates. Specifically, older age classes experienced lower survival when winters or the following springs were warm, while juveniles benefited from warmer winter temperatures. Although metabolic costs decrease with decreasing temperature in the hibernacula, arousal costs increase with decreasing temperature. Our results suggest that this trade‐off is experienced differently by immature and mature individuals. We also observed an increase in population density during that time period, suggesting resources are less limited today than they used to be. Cheatgrass is now dominating the study site and may provide a better food source to UGS than native plants did historically.     

Major disturbances test resilience at a long‐term boreal forest monitoring site

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Habitat differentiation among three Nigeria–Cameroon chimpanzee (Pan troglodytes ellioti) populations

Ecological niche models (ENMs) are often used to predict species distribution patterns from datasets that describe abiotic and biotic factors at coarse spatial scales. Ground‐truthing ENMs provide important information about how these factors relate to species‐specific requirements at a scale that is biologically relevant for the species. Chimpanzees are territorial and have a predominantly frugivorous diet. The spatial and temporal variation in fruit availability for different chimpanzee populations is thus crucial, but rarely depicted in ENMs. The genetic and geographic distinction within Nigeria–Cameroon chimpanzee (Pan troglodytes ellioti) populations represents a unique opportunity to understand fine scale species‐relevant ecological variation in relation to ENMs. In Cameroon, P. t. ellioti is composed of two genetically distinct populations that occupy different niches: rainforests in western Cameroon and forest–woodland–savanna mosaic (ecotone) in central Cameroon. We investigated habitat variation at three representative sites using chimpanzee‐relevant environmental variables, including fruit availability, to assess how these variables distinguish these niches from one another. Contrary to the assumption of most ENM studies that intact forest is essential for the survival of chimpanzees, we hypothesized that the ecotone and human‐modified habitats in Cameroon have sufficient resources to sustain large chimpanzee populations. Rainfall, and the diversity, density, and size of trees were higher at the rainforest. The ecotone had a higher density of terrestrial herbs and lianas. Fruit availability was higher at Ganga (ecotone) than at Bekob and Njuma. Seasonal variation in fruit availability was highest at Ganga, and periods of fruit scarcity were longer than at the rainforest sites. Introduced and secondary forest species linked with anthropogenic modification were common at Bekob, which reduced seasonality in fruit availability. Our findings highlight the value of incorporating fine scale species‐relevant ecological data to create more realistic models, which have implications for local conservation planning efforts.     

Laboratory and field tests of predation on the cereal leaf beetle,Oulema melanopus (Coleoptera: Chrysomelidae)

The cereal leaf beetle (CLB), Oulema melanopus (L.) (Coleoptera: Chrysomelidae), is an invasive pest in North America recently reported in the Canadian Prairies. We performed a series of laboratory assays to identify potential predators and a field study to quantify predation of CLB eggs. In no-choice Petri dish assays, ground beetles (Carabidae), rove beetles (Staphylinidae), and several common lady beetle species (Coccinellidae) were the most consistent predators of eggs and larvae. Nabis spp. (Hemiptera: Nabidae) and wolf spiders (Araneae: Lycosidae) consumed many larvae, but did not consume eggs. Hippodamia spp., Coccinella septempunctata (L.) (Coleoptera: Coccinellidae), and Pterostichus melanarius (Illiger) (Coleoptera: Carabidae) also fed on CLB eggs on potted plants when an alternative food source was available, Sitobion avenae (Fabricius) (Hemiptera: Aphididae). In our field study, we found an average of 24.5% of sentinel eggs disappeared over a 24?h period, likely due to predation. Our results suggest that generalist predators can play an important role in the biological control of CLB, and warrant further study.     

渔场重心信度测算及渔场重心修正理论构建——以闽南-台湾浅滩渔场二长棘鲷为例

渔场重心是表征渔场位置的重要参数,准确掌握渔场重心,对判断鱼类洄游路线、确定中心渔场、表征鱼群分布特征和变化规律具有重要意义。渔场重心计算采用的是固定物体重心计算方法,然而运动的鱼类和固定物体有着本质的区别。因此,由固定物体重心计算的渔场重心能否体现鱼群分布特征,值得深入研究。渔场重心信度是用于度量由固定物体重心计算的渔场重心表征鱼群分布特征的能力,体现渔场重心的可信程度,而渔场重心修正是为了提升渔场重心表征鱼群分布特征的能力,提高渔场重心信度,以准确掌握渔场重心。以闽南-台湾浅滩渔场二长棘鲷(Parargrops edita Tanaka)为例,采用渔场重心、几何中心和单位捕捞努力量渔获量(Catch Per Unit Effort,CPUE)为参数,首次建立了渔场重心信度测算及渔场重心修正理论和方法,分析了渔场重心信度,研究了渔场重心修正方法和渔场重心的分布特征,旨在从更精细地水平上掌握二长棘鲷渔场重心,为生态智慧在渔业资源开发和管理的应用提供可靠的数据支持。结果表明:(1)二长棘鲷渔场重心信度各月变化在0.12—1.00,平均值0.67,均方差0.31,各月渔场重心可信度波动较大,12月份和2月份渔场重心信度最大为1.00,鱼群对称和均匀分布于渔场重心,渔场重心可信度最高,3—8月份渔场重心信度低于0.70,鱼群在渔场重心周围的对称性和均匀度差,渔场重心可信度差,其中3月份渔场重心信度最小为0.12;(2)渔场重心信度不仅反映了渔场重心可信程度,还体现了鱼群在渔场重心周围的分布特征,可作为研究鱼群分布特征的重要参数,渔场重心信度低于0.70,渔场重心需要修正;(3)渔区修正系数用于判别鱼群所在渔区是否排除,通过去除渔区修正系数小于0.5的鱼群,能保留85%以上的鱼群数量,提高渔场重心信度0.70以上;(4)修改后的渔场重心变化规律较显著,4—5月份,幼鱼群体重心向西迁移,6—7月份,索饵群体重心向东北方向移动,8月份,索饵群体重心开始往南迁移,9—11月份,越冬群体重心逐渐向南移动,12月份,生殖群体重心继续往南迁移,1—3月份生殖群体主要集中在305渔区(119°15'E,23°15'N)附近进行生殖活动,鱼群少有迁移。