A Call for More Nuanced Dialogues About Trophy Hunting

Reported effects of trophy harvest often are controversial. The subject is nuanced and many studies lack details necessary to place their results in context. Consequently, many studies are misunderstood or their conclusions misapplied. We propose that all dialogues about trophy hunting include a definition of how they use the term trophy, details of variables measured and why they were selected, and explanations of temporal and spatial scales employed. Only with these details can potential effects of trophy hunting be understood in context and used for management and policy decisions. © 2021 The Wildlife Society.     

基于多尺度标记优化分水岭方法的油茶冠幅提取

针对尺度对地物空间结构的限制以及传统分水岭分割易产生树冠过分割等问题,选择长沙县明月村油茶基地为研究区,提出一种基于多尺度标记优化分水岭分割油茶树冠的方法。首先使用高分辨率无人机影像采集图像,分析影像特征,构建油茶分类体系,提取油茶林分布区域。其次,运用多尺度区域迭代增长方法提取树冠标记,将标记应用于多阈值尺度的分水岭变换,并结合Johnson指数选取树冠标记增长和分水岭阈值的最优尺度,实现油茶单木的准确识别。结果表明:多尺度标记优化分水岭方法在分离油茶单木时,树冠面积提取值与目视解译参考值的相对误差为9.4%;单木总体识别精度为89.4%,相对于传统的分水岭分割方法精度提高了34.8%;通过Johnson指数确定的最优迭代增长尺度为20,分水岭分割阈值尺度为85,对比不同尺度组合下的油茶冠幅提取结果,最优尺度下的油茶冠幅提取精度最高(R²=0.75)。多尺度标记优化分水岭方法能较准确地分离油茶树冠,将该方法应用于无人机影像树冠分割,可有效提高经济林调查的效率。     

宏观生态系统科学整合研究的多学科知识融合及其技术途径

综合认识大尺度的宏观生态系统结构功能、空间变异和动态演变的过程机理和模式机制,实现对生态系统变化及其对人类福祉影响的定量模拟、科学评估和预测预警,服务生态系统的利用保护及调控管理,是当代宏观生态系统科学的重要发展方向,正在孕育并形成大尺度的宏观生态系统科学整合生态学(IEMES)研究新领域。本研究通过对宏观生态系统科学整合生态学研究的基础理论、多学科知识融合途径及其关键技术问题的系统分析,形成以下几个基本认识: 1)宏观生态系统科学整合生态学研究是以区域、大陆和全球尺度的宏观生态系统为研究对象,采用多学科知识融合方法和技术,致力于解决人类社会发展的食物安全、资源安全、生态安全、环境安全等重大资源环境问题。2)宏观生态系统科学整合生态学研究的基本科技任务是: 理解宏观生态系统的结构功能基本属性,监测生态系统状态变化,解释生态系统时空演变规律,认知生态系统运维过程机理,定量评估生态系统功能状态及服务能力,预测生态系统动态演变及地理格局,预警生态系统变化及生态环境灾害。3)宏观生态系统科学整合生态学研究需要重新构造“多源数据分析-多模型模拟-多学科知识融合”的理论和方法学体系,发展“多尺度观测、多方法印证、多过程融合、跨尺度模拟”的多学科知识融合关键技术。4)大陆尺度的地基-空基-天基多时空尺度生态系统观测试验网络是承载多学科知识深度融合研究的基础科技设施,需要围绕区域、大陆和全球尺度的宏观生态系统科学问题,发展多要素-多过程-多界面-多介质-多尺度-多方法的多学科维度生态学知识融合关键技术。     

乡村景观生物多样性研究进展

乡村景观是一种人文和自然共生的复合生态系统, 为生物多样性的维持提供了支持。目前, 中国传统乡村地区生物多样性的维持正面临着农业集约化、人工林树种单一化、非农业用地急剧扩张及生态传承机制解体等复杂多样的威胁, 亟待展开深入研究。本文在总结乡村景观生物多样性相关概念及特征的基础上, 通过文献分析概括了国际乡村景观生物多样性的热点研究方向, 包括农业集约化下的生物多样性管理、区域尺度乡村景观与生物多样性的协同关系、局地尺度不同乡村景观类型的物种多样性及乡村景观中的生物文化多样性, 进一步梳理了国内在相关研究方向上的主要进展并指出研究不足。在此基础上提出未来研究展望, 包括突出生物文化多样性特征、加强多时空尺度分析、深化动态维持机制研究、推进生物多样性研究在乡村生态景观规划中的全过程应用等建议。     

Cross-scale quality assessment of a mechanistic cation exchange chromatography model

Cation exchange chromatography (CEX) is an essential part of most monoclonal antibody (mAb) purification platforms. Process characterization and root cause investigation of chromatographic unit operations are performed using scale down models (SDM). SDM chromatography columns typically have the identical bed height as the respective manufacturing-scale, but a significantly reduced inner diameter. While SDMs enable process development demanding less material and time, their comparability to manufacturing-scale can be affected by variability in feed composition, mobile phase and resin properties, or dispersion effects depending on the chromatography system at hand. Mechanistic models can help to close gaps between scales and reduce experimental efforts compared to experimental SDM applications. In this study, a multicomponent steric mass-action (SMA) adsorption model was applied to the scale-up of a CEX polishing step. Based on chromatograms and elution pool data ranging from laboratory- to manufacturing-scale, the proposed modeling workflow enabled early identification of differences between scales, for example, system dispersion effects or ionic capacity variability. A multistage model qualification approach was introduced to measure the model quality and to understand the model's limitations across scales. The experimental SDM and the in silico model were qualified against large-scale data using the identical state of the art equivalence testing procedure. The mechanistic chromatography model avoided limitations of the SDM by capturing effects of bed height, loading density, feed composition, and mobile phase properties. The results demonstrate the applicability of mechanistic chromatography models as a possible alternative to conventional SDM approaches.     

Local temperatures inferred from plant communities suggest strong spatial buffering of climate warming across Northern Europe

Recent studies from mountainous areas of small spatial extent (<2500 km²) suggest that fine‐grained thermal variability over tens or hundreds of metres exceeds much of the climate warming expected for the coming decades. Such variability in temperature provides buffering to mitigate climate‐change impacts. Is this local spatial buffering restricted to topographically complex terrains? To answer this, we here study fine‐grained thermal variability across a 2500‐km wide latitudinal gradient in Northern Europe encompassing a large array of topographic complexities. We first combined plant community data, Ellenberg temperature indicator values, locally measured temperatures (LmT) and globally interpolated temperatures (GiT) in a modelling framework to infer biologically relevant temperature conditions from plant assemblages within <1000‐m² units (community‐inferred temperatures: CiT). We then assessed: (1) CiT range (thermal variability) within 1‐km² units; (2) the relationship between CiT range and topographically and geographically derived predictors at 1‐km resolution; and (3) whether spatial turnover in CiT is greater than spatial turnover in GiT within 100‐km² units. Ellenberg temperature indicator values in combination with plant assemblages explained 46–72% of variation in LmT and 92–96% of variation in GiT during the growing season (June, July, August). Growing‐season CiT range within 1‐km² units peaked at 60–65°N and increased with terrain roughness, averaging 1.97 °C (SD = 0.84 °C) and 2.68 °C (SD = 1.26 °C) within the flattest and roughest units respectively. Complex interactions between topography‐related variables and latitude explained 35% of variation in growing‐season CiT range when accounting for sampling effort and residual spatial autocorrelation. Spatial turnover in growing‐season CiT within 100‐km² units was, on average, 1.8 times greater (0.32 °C km^?1) than spatial turnover in growing‐season GiT (0.18 °C km^?1). We conclude that thermal variability within 1‐km² units strongly increases local spatial buffering of future climate warming across Northern Europe, even in the flattest terrains.     

Environmental gradients shift the direction of the relationship between native and alien plant species richness

Aim

To assess how environmental, biotic and anthropogenic factors shape native–alien plant species richness relationships across a heterogeneous landscape.

Location

Banks Peninsula, New Zealand.

Methods

We integrated a comprehensive floristic survey of over 1200 systematically located 6 × 6 m plots, with corresponding climate, environmental and anthropogenic data. General linear models examined variation in native and alien plant species richness across the entire landscape, between native‐ and alien‐dominated plots, and within separate elevational bands.

Results

Across all plots, there was a significant negative correlation between native and alien species richness, but this relationship differed within subsets of the data: the correlation was positive in alien‐dominated plots but negative in native‐dominated plots. Within separate elevational bands, native and alien species richness were positively correlated at lower elevations, but negatively correlated at higher elevations. Alien species richness tended to be high across the elevation gradient but peaked in warmer, mid‐ to low‐elevation sites, while native species richness increased linearly with elevation. The negative relationship between native and alien species richness in native‐dominated communities reflected a land‐use gradient with low native and high alien richness in more heavily modified native‐dominated vegetation. In contrast, native and alien richness were positively correlated in very heavily modified alien‐dominated plots, most likely due to covariation along a gradient of management intensity.

Main conclusions

Both positive and negative native–alien richness relationships can occur across the same landscape, depending on the plant community and the underlying human and environmental gradients examined. Human habitat modification, which is often confounded with environmental variation, can result in high alien and low native species richness in areas still dominated by native species. In the most heavily human modified areas, dominated by alien species, both native and alien species may be responding to similar underlying gradients.