Conceptual Model Development for Invasive Species and a Regional Risk Assessment Case Study: The European Green Crab,Carcinus maenas,at Cherry Point,Washington, USA

The goal of this article was to generate a method of regional scale ecological risk assessment using an adaptation Relative Risk Model (RRM). As a case study we performed a quantitative, regional risk assessment of an invasive species, the European green crab (Carcinus maenas) at Cherry Point, Washington, USA. The conceptual model was modified from the RRM and incorporates the structure of the hierarchical patch dynamic paradigm. The ranks and filters were integrated to determine the relative contribution of each source of C. maenas to risk as well as the risk to selected biological endpoints, habitats and sub-regions for two source scenarios: (1) current conditions (2004) and (2) future conditions during an El Nino year. The results suggest that the habitat and endpoint with the greatest risk are the eelgrass habitat and the juvenile Dungeness crab, respectively. The Cherry Point subregion was identified as the area having the most risk in the first source scenario, while the Lummi Bay sub-region is most at risk during an El Nino event. The risk of impacts is substantially higher for all endpoints, habitats and sub-regions when El Nino–driven current dispersal is considered. The methodology applied in this case study can be modified and applied to determine the risk of introduction and impacts of other invasive species to the Strait of Georgia, Puget Sound, and other coastal areas.     

Local predation risk and matrix permeability interact to shape movement strategy

In fragmented landscapes, the reduced connectivity among patches drives the evolution of movement strategies through an increase of transience costs. Reduced movements may further alter heterogeneity in biotic and abiotic conditions experienced by individuals. The joint action of local conditions and matrix permeability may shape emigration decisions. Here, we tested the interactive effects of predation risk and matrix permeability on movement propensity, movement costs and movers’ phenotype in the common toad Bufo bufo. In a full‐crossed experimental design, we assessed the movement propensity of juveniles in three connectivity treatments (from poorly to highly permeable matrix), with or without predation risk in their living patch. We also assessed the relationships between movement propensity and morphological traits (i.e. body and leg length) and how it affected the movement cost (i.e. mass loss). Movement propensity increased in presence of predation risk, while matrix permeability had no effect. However, matrix permeability interacted with predation risk to influence movers’ phenotype and the physiological cost they endured while moving. In particular, a well‐known movement syndrome in toads (i.e. movement propensity positively related to longer legs) depended on the interaction between matrix permeability and predation risk and resulted in differences in mass loss among matrix types. Movers lost more mass on average than residents except when they also displayed longer legs or when they crossed the most permeable matrix in the presence of predation risk. Our results show that matrix permeability shapes the physiological cost of dispersal by changing the identity of individuals moving away from local conditions. As the movers’ phenotype can importantly alter (meta)population dynamics, context‐dependency of dispersal syndromes should be considered in studies predicting the functioning of human‐altered natural systems.     

Weather effects on birds of different size are mediated by long‐term climate and vegetation type in endangered temperate woodlands

Species occurrence is influenced by a range of factors including habitat attributes, climate, weather, and human landscape modification. These drivers are likely to interact, but their effects are frequently quantified independently. Here, we report the results of a 13‐year study of temperate woodland birds in south‐eastern Australia to quantify how different‐sized birds respond to the interacting effects of: (a) short‐term weather (rainfall and temperature in the 12 months preceding our surveys), (b) long‐term climate (average rainfall and maximum and minimum temperatures over the period 1970–2014), and (c) broad structural forms of vegetation (old‐growth woodland, regrowth woodland, and restoration plantings). We uncovered significant interactions between bird body size, vegetation type, climate, and weather. High short‐term rainfall was associated with decreased occurrence of large birds in old‐growth and regrowth woodland, but not in restoration plantings. Conversely, small bird occurrence peaked in wet years, but this effect was most pronounced in locations with a history of high rainfall, and was actually reversed (peak occurrence in dry years) in restoration plantings in dry climates. The occurrence of small birds was depressed—and large birds elevated—in hot years, except in restoration plantings which supported few large birds under these circumstances. Our investigation suggests that different mechanisms may underpin contrasting responses of small and large birds to the interacting effects of climate, weather, and vegetation type. A diversity of vegetation cover is needed across a landscape to promote the occurrence of different‐sized bird species in agriculture‐dominated landscapes, particularly under variable weather conditions. Climate change is predicted to lead to widespread drying of our study region, and restoration plantings—especially currently climatically wet areas—may become critically important for conserving bird species, particularly small‐bodied taxa.     

Repurposing fed-batch media and feeds for highly productive CHO perfusion processes

Perfusion is a cell culture mode that is gaining popularity for the manufacture of monoclonal antibodies and their derivatives. The cell culture media supporting perfusion culture need to support higher cell densities than those used in fed-batch culture. Therefore, when switching from a fed-batch to a perfusion mode, a new medium need to be developed which supports high cell densities, high productivity, and favorable product quality. We have developed a method for deriving perfusion culture media based on existing fed-batch media and feeds. We show that we can obtain culture media that successfully support perfusion cultures in a single-use rocking bioreactor system at cell-specific perfusion rates below 25 pL⁻¹ cell⁻¹ day⁻¹. High productivities and favorable product quality are also achievable.     

GDF15 Provides an Endocrine Signal of Nutritional Stress in Mice and Humans

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