Lakes are complex ecosystems composed of distinct habitats coupled by biological, physical and chemical processes. While the ecological evolutionary characteristics aquatic organisms reflect habitat coupling in lakes, ecology has largely studied pelagic, benthic riparian isolation from each other. Here, we summarize several patterns that highlight importance discuss their implications for understanding ecosystem processes lakes. We pay special attention to fishes because they play...

The total world catch from marine and freshwater wild stocks has peaked may be slightly declining. There appear to few significant resources developed, the majority of world's fish are intensively exploited. Many ecosystems have been profoundly changed by fishing other human activities. Although most major fisheries continue produce substantial sustainable yield, a number severely overfished, many more heading toward depletion. heavily subsidized, which encourages overfishing provides...

Abstract Aim Spatial analysis of the distribution and density species is continuing interest within theoretical applied ecology. Species models (SDMs) are being increasingly used to analyse count, presence–absence presence‐only data sets. There a growing literature on dynamic SDMs (which incorporate temporal variation in distribution), joint simultaneously correlated multiple species) geostatistical account for similarity between nearby sites caused by unobserved covariates). However, no...

Summary Predicting and explaining the distribution density of species is one oldest concerns in ecology. Species distributions can be estimated using geostatistical methods, which estimate a latent spatial variable observed variation densities, but methods may imprecise for with low densities or few observations. Additionally, simple fail to account correlations among generally such cross‐correlations as post hoc exercise. We therefore present factor analysis ( SFA ), model estimating...

Summary 1. Migration timing in animals has important effects on life‐history transitions. Human activities can alter migration of animals, and understanding the such disruptions remains an goal for applied ecology. Anadromous Pacific salmon ( Oncorhynchus spp.) inhabit fresh water as juveniles before migrating to ocean where they gain >90% their biomass returning adults reproduce. Although construction dams delayed juvenile many populations, we currently lack a synthesis patterns how...

Environmental change can shift the phenotype of an organism through either evolutionary or nongenetic processes. Despite abundant evidence phenotypic in response to recent climate change, we typically lack sufficient genetic data identify role evolution. We present a method using characterize hypothesized natural selection and environmentally driven shifts (plasticity). modeled historical environmental predictors interannual variation mean population multivariate state-space model framework....

Long‐term ecological data sets present opportunities for identifying drivers of community dynamics and quantifying their effects through time series analysis. Multivariate autoregressive (MAR) models are well known in many other disciplines, such as econometrics, but widespread adoption MAR methods ecology natural resource management has been much slower despite some widely cited examples. Here we review previous applications highlight ability to identify abiotic biotic population dynamics,...

Abstract How local geomorphic and hydrologic features mediate the sensitivity of stream thermal regimes to variation in climatic conditions remains a critical uncertainty understanding aquatic ecosystem responses climate change. We used stable isotopes hydrogen oxygen estimate contributions snow rainfall 80 boreal streams show that differences contribution are controlled by watershed topography. Time series analysis revealed rain‐dominated, low‐elevation watersheds were 5–8 times more...

Ecology Letters (2011) 14: 364–372 Abstract While the importance of terrestrial linkages to aquatic ecosystems is well appreciated, degree support consumers remains debated. Estimates contributions lake zooplankton have omitted a key food source, phytoplankton produced below mixed layer. We used carbon and nitrogen stable isotope data from 25 Pacific Northwest lakes assess relative particulate organic matter (POM) layer, layer detritus zooplankton. Zooplankton deep POM were depleted in 13C...

ABSTRACT Species with complex life cycles, such as anadromous fish that perform spawning migrations between freshwater and the ocean, may be particularly sensitive to global change because marine habitats experience distinct shifts in climate ecosystem dynamics. Abundances of wild steelhead trout ( Oncorhynchus mykiss ) have declined across most their range over past 40–50 years. We examined whether declines survival can linked changing conditions species interactions. A novel hierarchical...

Diel vertical migration (DVM) is a widespread phenomenon in aquatic organisms, yet the adaptive significance of this behavior still unclear. In particular, diel by juvenile sockeye salmon (Oncorhynchus nerka) has received considerable attention. We studied how changes light environment affect DVM Alaskan lakes through foraging rates and predation risk. Using hydroacoustics to track temporal fish distribution, we found clear patterns strong, significant correlation between mean depth amount...

Detecting and forecasting the effects of changing climate on natural exploited populations represent a major challenge to ecologists resource managers. These efforts are complicated by underlying density-dependent processes differential responses predators their prey climate. We explored density-dependence growth juvenile sockeye salmon densities zooplankton in Wood River system southwestern Alaska. fit dynamic time-series models data collected between 1962 2002 describing sockeye, timing...

The viability of populations is influenced by driving forces such as density dependence and climate variability, but most population analyses (PVAs) ignore these factors because data limitations. Additionally, simplified PVAs produce limited measures annual growth rate (lamda) or extinction risk. Here we developed a "mechanistic" PVA threatened Chinook salmon (Oncorhynchus tshawytscha) in which, based on 40 years detailed data, related freshwater recruitment juveniles to spawners, third-year...

Current efforts to conserve Pacific salmon (Oncorhynchus spp.) rely on a variety of information sources, including empirical observations, expert opinion, and models. Here we outline framework for incorporating detailed density-dependent population growth, habitat attributes, hatchery operations, harvest management into conservation planning in time-varying, spatially explicit manner. We multistage Beverton–Holt model describe the production from one life stage next. use literature construct...

Dams designed for hydropower and other purposes alter the environments of many economically important fishes, including Chinook salmon (Oncorhynchus tshawytscha). We estimated that dams on Rogue River, Willamette Cowlitz Fall Creek decreased water temperatures during summer increased fall winter. These thermal changes undoubtedly impact behavior, physiology, life histories salmon. For example, relatively high winter should speed growth development, leading to early emergence fry....

Summary 1. Anadromous salmon transport marine‐derived nutrients and carbon to freshwater riparian ecosystems upon their return natal spawning systems. The ecological implications of these subsidies on the trophic ecology resident fish remain poorly understood despite broad recognition potential importance. 2. We studied within‐year changes in ration size, composition stable isotope signature diets two salmonids (rainbow trout, Oncorhynchus mykiss ; Arctic grayling, Thymallus arcticus )...

Abstract Effective conservation and management of natural resources requires accurate predictions ecosystem responses to future climate change, but environmental science has largely failed produce these reliable forecasts. The response Pacific salmon ( Oncorhynchus spp.) a changing environment continued anthropogenic disturbance is particular interest the public because their high economic, social, cultural value. While numerous retrospective analyses show strong correlation between past...

Lake Washington is arguably the most famous case study of lake pollution and subsequent recovery, widely cited story implicates just a few major players in lake's food web transformations. "The story" historically highlights key that negatively affect other taxa—filamentous cyanobacteria, influential grazer Daphnia, its predator Neomysis. This model has been based variously on experiments, observation, educated inference. Here we tested robustness historical conceptual single multivariate...

Quantifying the variability in delivery of ecosystem services across landscape can be used to set appropriate management targets, evaluate resilience and target conservation efforts. Ecosystem functions may exhibit portfolio-type dynamics, whereby diversity within lower levels promotes stability at more aggregated levels. Portfolio theory provides a framework characterize relative performance among ecosystems processes that drive differences performance. We assessed Pacific salmon...

Abstract A central problem in understanding how species respond to global change is parsing the effects of local drivers population dynamics from regional and that are shared among populations. Management conservation efforts typically focus on a particular would benefit greatly being able separate environmental processes at local, regional, scales. One way addressing this challenge integrate data across multiple populations use multivariate time series approaches estimate independent...

The decline in salmon and steelhead populations the Columbia River Basin has been well documented, as have decades-long, $9 billion restoration spending efforts by federal state agencies. These are mainly tied to Endangered Species Act (ESA) mandates for recovery of wild, naturally-spawning threatened or endangered fish species. impact these remains poorly understood; many observers, including courts, long concerned lack evidence recovery. Most studies evaluating examined individual projects...