Subpopulation structure of caribou (Rangifer tarandus L.) in arctic and subarctic Canada

Effective management and conservation of species, subspecies, or ecotypes require an understanding of how populations are structured in space. We used satellite-tracking locations and hierarchical and fuzzy clustering to quantify subpopulations within the behaviorally different barren-ground caribou (Rangifer tarandus groenlandicus), Dolphin and Union island caribou (R. t. groenlandicus x pearyi), and boreal (R. t. caribou) caribou ecotypes in the Northwest Territories and Nunavut, Canada. Using a novel approach, we verified that the previously recognized Cape Bathurst, Bluenose-West, Bluenose-East, Bathurst, Beverly, Qamanirjuaq, and Lorillard barren-ground subpopulations were robust and that the Queen Maude Gulf and Wager Bay barren-ground subpopulations were organized as individuals. Dolphin and Union island and boreal caribou formed one and two distinct subpopulation, respectively, and were organized as individuals. Robust subpopulations were structured by strong annual spatial affiliation among females; subpopulations organized as individuals were structured by migratory connectivity, barriers to movement, and/or habitat discontinuity. One barren-ground subpopulation used two calving grounds, and one calving ground was used by two barren-ground subpopulations, indicating that these caribou cannot be reliably assigned to subpopulations solely by calving-ground use. They should be classified by annual spatial affiliation among females. Annual-range size and path lengths varied significantly among ecotypes, including mountain woodland caribou (R. t. caribou), and reflected behavioral differences. An east-west cline in annual-range sizes and path lengths among migratory barren-ground subpopulations likely reflected differences in subpopulation size and habitat conditions and further supported the subpopulation structure identified.     

Individual- and condition-dependent effects on habitat choice and choosiness

Research on consistent individual differences in behavior, or “behavioral syndromes”, continues to grow rapidly, and yet, the aspects of behavior under consideration have remained remarkably limited. Here, we consider individual variation in consistency of choice (termed here “choosiness”), as expressed during habitat choice. We repeatedly tested the responses of female Western Black Widows, Latrodectus hesperus, to two cues of habitat quality: prey chemical cues and variation in web site illuminance. We estimated females’ response by the distance they positioned themselves from (1) the source of prey chemical cues and (2) the darkest edge of our test arena. Individuals with low variance in their responses are deemed more “choosy”, whereas individuals with high variance are deemed less “choosy”. Generally, most females initiated web construction near the source of the prey chemical cues and tended to place themselves in low-light conditions. However, we detected strong, repeatable differences in females’ intensity of response, and within-individual variance of response (i.e., choosiness) was correlated across situations: females with highly consistent responses towards cricket chemical cues also exhibited highly consistent responses towards variation in light conditions. When deprived of food for extended periods, females were indistinguishable in their responses towards prey chemical cues, but tended to initiate web construction in brighter lighting conditions. Food-deprived females universally exhibited higher variance and diminished consistency in their responses (i.e., they were less choosy). Additionally, higher choosiness was associated with greater mass loss during choice trials, suggesting choosiness is energetically costly. Our results demonstrate that consistency of response to environmental cues is yet another element of behavior that varies among individuals and variation in choosiness could beget speed/quality trade-offs during animal decision making.     

内在安全的生产,对清洁生产的一种正常的补充

内在的安全性,是一种利用没有毒性、可燃性或不稳定性的工艺与材料的方法,它通常被认为是化工厂设计的一个重要概念.受到清洁生产成功发展的鼓舞,进行了一项类似的有关内在安全生产的发展可行性研究.在1997-1998年进行的初步试验案例中,发展并检验了一个产生内在安全的技术选择的方法论.该研究表明,大部分选择的偿还时间少于两年,而且内在安全的生产是一个可行的概念,有可能同时产生巨大的安全与经济成效的改善,并且可以结合进清洁生产计划.     

Ecological versatility and the decline of coral feeding fishes following climate driven coral mortality

Coral reefs are under threat due to climate-mediated coral mortality, which affects some reef coral genera more severely than others. The impact this has on coral reef fish is receiving increasing attention, with one focal area assessing impacts on fish that feed directly on live coral. It appears that the more specialised a species of corallivore, the more susceptible it is to coral declines. However data are sparse for the Indian Ocean, and little is known about why some corals are preferentially fed upon over others. Here I assess feeding specialisation in three species of coral feeding butterflyfish in the Chagos Archipelago, central Indian Ocean, assess the food quality of the coral genera they target and document patterns of decline in the Seychelles following a severe coral mortality event. Cheatodon trifascialis was the most specialised coral feeder, preferentially selecting for Acropora corals, however, when Acropora was scarce, individuals showed considerable feeding plasticity, particularly for the dominant Pocillopora corals. C. trifasciatus also preferentially fed on Acropora corals, but fed on a much more diverse suite of corals and also displayed some selectivity for Porites. C. auriga is a facultative corallivore and consumed ∼55% live coral, which lies within the wide range of coral dependence reported for this species. C:N ratio analysis indicated Lobophyllia and Acropora have the highest food quality, with Pocillopora having the lowest, which conforms with diet selection of corallivores and helps explain preferential feeding. Obligate specialist feeders displayed the greatest declines through coral mortality in the Seychelles with obligate generalists also declining substantially, but facultative feeders showing little change. Clearly a greater understanding of the species most vulnerable to disturbance, their habitat requirements and the functional roles they play will greatly assist biodiversity conservation in a changing climate.     

Analysis of Daily Peaking and Run‐of‐River Operations with Flow Variability Metrics,Considering Subdaily to Seasonal Time Scales

Environmental flows are an important consideration in licensing hydropower projects as operational flow releases can result in adverse conditions for downstream ecological communities. Flow variability assessments have typically focused on pre‐ and post‐dam conditions using metrics based on daily averaged flow values. This study used subdaily and daily flow data to assess environmental flow response to changes in hydropower operations from daily peaking to run‐of‐river. An analysis tool was developed to quantify flow variability metrics and was applied to four hydropower projects. Significant differences were observed between operations at the 99% confidence level in the median flow values using hourly averaged flow datasets. Median daily rise and fall rates decreased on average 34.5 and 27.9%, respectively, whereas median hourly rise and fall rates decreased on average 50.1 and 50.6%, respectively. Differences in operational flow regimes were more pronounced in the hourly averaged flow datasets and less pronounced or nonexistent in the daily averaged flow datasets. These outcomes have implications for the development of ecology‐flow relationships that quantify effects of flow on processes such as fish stranding and displacement, along with habitat stability. Results indicate that flow variability statistics should be quantified using subdaily datasets to accurately represent the nature of hydropower operations, especially for daily peaking facilities.