A5075962121- Fish Ecology and Management Studies
- Freshwater macroinvertebrate diversity and ecology
- Aquatic Invertebrate Ecology and Behavior
- Aquatic Ecosystems and Phytoplankton Dynamics
- Ecology and Vegetation Dynamics Studies
- Hydrology and Sediment Transport Processes
- Species Distribution and Climate Change
- Marine and fisheries research
- Fire effects on ecosystems
- Plant and animal studies
- Animal Ecology and Behavior Studies
- Soil and Water Nutrient Dynamics
- Rangeland and Wildlife Management
- Aquatic Ecosystems and Biodiversity
- Fish biology, ecology, and behavior
- Wildlife Ecology and Conservation
- Crustacean biology and ecology
- Coastal wetland ecosystem dynamics
- Marine and coastal ecosystems
- Amphibian and Reptile Biology
- Environmental DNA in Biodiversity Studies
- Genetic and phenotypic traits in livestock
- Ecology and biodiversity studies
- Environmental Toxicology and Ecotoxicology
- Hydrology and Watershed Management Studies
University of California, Santa Barbara
2015-2024
Microsoft Research (United Kingdom)
2024
Commonwealth Scientific and Industrial Research Organisation
2018-2020
University of California System
2001-2014
National Oceanic and Atmospheric Administration
1998
Scottish Agricultural Science Agency
1996
University of California, Berkeley
1984-1994
Cornell University
1990
Dalhousie University
1990
Museum of Vertebrate Zoology
1984
Abstract Although trophic cascades (indirect effects of predators on plants via herbivores) occur in a wide variety food webs, the magnitudes their are often quite variable. We compared responses herbivore and plant communities to predator manipulations 102 field experiments six different ecosystems: lentic (lake pond), marine, stream benthos, marine plankton, terrestrial (grasslands agricultural fields). Predator varied considerably among systems were strongest benthos weakest plankton...
Trophic cascades have been documented in a diversity of ecological systems and can be important determining biomass distribution within community. To date, the literature on trophic has focused whether which occur. Many biological (e.g., productivity : ratios) methodological experiment size or duration) factors vary with ecosystem data were collected, but type, per se, does not provide mechanistic insights into controlling cascade strength. Here, we tested various hypotheses about why occur...
We evaluate the goals of meta-analysis, critique its recent application in ecology, and highlight an approach that more explicitly links meta-analysis ecological theory. One goal is testing null hypotheses no response to experimental manipulations. Many ecologists, however, are interested quantitatively measuring processes examining their systematic variation across systems conditions. This latter requires a suite diverse, ecologically based metrics effect size, with each appropriately...
Fire is a prevalent feature of many landscapes and has numerous complex effects on geological, hydrological, ecological, economic systems. In some regions, the frequency intensity wildfire have increased in recent years are projected to escalate with predicted climatic landuse changes. addition, prescribed burns continue be used parts world clear vegetation for development projects, encourage desired vegetation, reduce fuel loads. Given prevalence fire landscape, authors papers this special...
Some studies suggest that lotic populations of brown trout (Salmo trutta) are regulated through density-dependent mortality and emigration to the extent mean growth rates resident survivors unrelated densities. To test this, we studied relationship between density growth, mortality, in two alpine streams a set stream channels eastern California. We sampled at scale “segments” (5–31 m long riffles, runs, pools) “sections” (340–500 length) Convict Creek over 3-yr period. Trout were also during...
We present four lines of evidence that the magnitude prey exchange (=immigration/emigration) among substrate patches has an overwhelming influence on perceived effects predators populations. (1) An extensive review literature predation in benthic and littoral freshwater revealed a significant relationship between rate observed predator impact. In streams, studies showing used cages with smaller mesh sizes than nonsignificant effects. Similarly, there was highly correlation cage size impact...
Abstract Although the scale‐dependence of ecological patterns and processes is recognized by freshwater ecologists, current knowledge scale effects rudimentary non‐quantitative. We review issues spatial temporal in this paper to highlight conceptual problems relating some potential solutions. present examples how a study influences observed their interpretation, discuss size an experimental arena degree which dynamics studied populations are influenced exchange (immigration emigration). The...
The effects of macroalgae on stream invertebrates were studied in riffle zones a coastal southern California stream. Dense growths (Cladophora glomerata, Nostoc sp.) experimentally removed at different times the year and years, insect communities which developed compared with those unmanipulated controls. Marl precipitated by algae was also one experiment. presence associated greater total densities taxon richness invertebrates, nearly all taxa responded significantly to algal removal least...
Mysis relicta clearance rates were not affected by changes in prey and predator density single-prey systems where Epischura nevadensis late instars used as food. A comparison of the results obtained from single-, two-prey, multiple-prey revealed that E. Diaptomus tyrrelli males significantly presence abundance alternative prey.When offered natural assemblages, smallest preyed preferentially on available (Bosmina, Ceriodaphnia, nauplii) while larger showed an increased preference for...
Although theoretical and empirical studies show that spatial heterogeneity has important effects on the dynamics of populations structure communities, there been little rigorous quantification terms like "patchiness" or "spatial heterogeneity" in lotic systems. In order to compare different systems understand causes consequences heterogeneity, we must first be able quantitatively measure it. Spatial many aspects change with scale our observations, so need a battery descriptive measures...
The value of meta-analysis in ecology hinges on the reproducibility patterns generated by quantitative synthesis. Meta-analysts will vary criteria they use to screen studies and select data within studies, even when addressing exactly same question. We summarize some many decisions that an ecologist must make deciding what include a then show, using multiple meta-analyses taken from literature stream predation experiments, meta-analytic conclusions can be colored selection are not...
We observed several freshwater predators, including the odonate larvae Pachydiplax longipennis and Anax junius, hemipterans Notonecta unifasciata Buenoa scimitra, dytiscid larva Acilius semisulcatus, juvenile Gambusia affinis, feeding on a variety of microcrustacean prey determined frequency component parts predator–prey interactions (encounter, attack, capture, ingestion). Encounter rates were most important determinant predator selectivity when predators presented with prey. When only...
Anthropogenic increases in nitrogen (N) and phosphorus (P) concentrations can strongly influence the structure function of ecosystems. Even though lotic ecosystems receive cumulative inputs nutrients applied to deposited on land, no comprehensive assessment has quantified nutrient-enrichment effects within streams rivers. We conducted a meta-analysis published studies that experimentally increased N and/or P rivers examine how enrichment alters ecosystem (state: primary producer consumer...
In an alpine area of the Sierra Nevada California, naturally acidic waters and introduced fishes both strongly affect distributions native amphibians, zooplankton, macroinvertebrates. The study in Kings Canyon National Park contains 104 lakes with pH values between 5.0 9.3, including 10 < 6.0 (defined here as lakes) 18 trout. We surveyed 33 these (8 acidic, 7 non-acidic trout, without trout) for water chemistry faunal assemblages. Yellow-legged frog tadpoles (Rana muscosa), common...
Biological processes, such as predator-prey or competitive interactions, occur at multiple spatial and temporal scales, but their impacts on the distribution, abundance, fitness of organisms may only be detectable some scales. This is because 1) small scale (local) processes constrained by large-scale (regional) 2) influence organism movement changes with scale, 3) small-scale interact produce variation that obscures patterns. Most ecologists would like to know relevance observations...
In situ enclosure experiments were used to asses the importance of competition population dynamics three cladocerans (Daphnia pulex, Moina affinis, and Ceriodaphnia sp.) in a small pond. Competitive effects nonlinear functions cladoceran density, both intra interspecific important determinants pond populations. The data suggested that degree was dependent on resource levels age competitors. major predator, Chaoborus, able control prey populations only when densities phytoplankton low.
Summary We investigated the effects of a wildfire on stream physical, chemical and biological characteristics in Mediterranean climate, comparing community structure consumer resource use burned versus unburned catchments Santa Barbara County, CA , U.S.A. Canopy cover was lower water temperature higher streams draining basins where riparian vegetation than or remained intact. Stream flow suspended sediment concentrations during large post‐fire storms wet season nutrient levels were...
Abstract We studied benthic macroinvertebrate communities in 12 mid‐elevation mountain streams the Sierra Nevada, California. Data were collected at nine times (seven springs and two autumns) over a 14‐year period of variable hydrological conditions, including years flood extreme unprecedented drought. The taxonomic trait structures similar during wet average but became increasingly different as drought continued smaller intermittent. density total invertebrates, primarily chironomids,...