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Because of GLOBEC's focus on population dynamics, species‐level research is central to the programme, and most field, retrospective and modeling studies were directed at target species defined on the basis of their suitability for use in the comparative approach or their trophic role in the ecosystem. Target species may be economically significant due to their contribution to local, regional, and national economies through subsistence, commercial enterprise, and use by indigenous peoples. Target species of conservation significance may be the subjects of regional, national, or international conservation agreements. Target species of social or cultural significance have value to human communities because of their historical, aesthetic, educational, or recreational value. GLOBEC target species are heavily weighted towards marine pelagic organisms, particularly zooplankton. However, vertebrates with largely (seabirds and seals) or wholly (whales) pelagic life histories have been studied in some ecosystems, as have anadromous fish whose life history is not entirely marine. Here, this chapter reviews major groups of GLOBEC target species: Calanus and other large copepods, salmonids, cod, small pelagic fish, and large apex predators.

GLOBEC studies focused on biological—physical interactions of target species in different study regions, emphasizing responses of organisms to varying physical forces. Population‐level processes were shown to be important, with ecological responses often being ecosystem‐specific. The timing of biological events (e.g. spring bloom, entry/exit from diapause, and fish spawning) is susceptible to environmental change. Many species can adapt their feeding modes and diets, but changes in mortality imposed by heavy fishing can disrupt biological systems, making them increasingly vulnerable to perturbations. Some organisms can move away from unfavourable conditions, changing the vertical and horizontal linkages between disparate ecosystems with unknown consequences. Trophic controls in food webs vary over time and space and food web structures also change, both over the short term and through shifts in regimes, sometimes irreversibly. There is an ongoing requirement to integrate ecological processes, from biogeochemistry to top predators, to understand potential consequences of global change.

Hydraulic rating methods define the relationship between flow volume (discharge) and the amount and type of habitat provided during the passage of flow along a stream channel. Methods include wetted perimeter or area analysis, flow events method, and various habitat simulation techniques and frameworks. The Instream Flow Incremental Methodology (IFIM) and its core component, the physical habitat modeling platform PHABSIM, are widely used. The main prediction phase of IFIM combines information derived from hydraulic simulation with data on habitat preferences of target species (usually fish), and prediction of habitat availability (expressed as weighted usable area, WUA) at different discharges. A WUA time series plot can be developed to depict changes in habitat over time as a consequence of flow alterations.

This chapter explores ongoing debates surrounding the environmental safety of genetically modified (GM) crops. Systematic review and meta-analysis provide convincing evidence that Bt crops are safer than insecticides for non-target invertebrate species, such as honeybees and ladybird beetles. In addition, widespread adoption of Bt crops has resulted in reduced use of insecticides and other benefits for the environment. Despite such evidence, there remains a substantial opinion gap between the general public and scientists regarding the safety of GM crops. While systematic review and meta-analysis can help to correct for bias in environmental and conservation science, the oversimplification of environmental issues into blackand- white dichotomies such as pro- versus anti-GM crops can stymie the adoption of genuine solutions.