Jason L. Hwan
A5023528283- Fish Ecology and Management Studies
- Hydrology and Sediment Transport Processes
- Hydrology and Watershed Management Studies
- Soil and Water Nutrient Dynamics
- Freshwater macroinvertebrate diversity and ecology
- Peatlands and Wetlands Ecology
- Genetically Modified Organisms Research
- Conservation, Biodiversity, and Resource Management
- Environmental DNA in Biodiversity Studies
- Animal Ecology and Behavior Studies
- Forest Ecology and Biodiversity Studies
- Species Distribution and Climate Change
- Wildlife Ecology and Conservation
- Fish biology, ecology, and behavior
- Zoonotic diseases and public health
- Microbial Community Ecology and Physiology
- Crustacean biology and ecology
- Wildlife-Road Interactions and Conservation
- Land Use and Ecosystem Services
- Environmental Conservation and Management
- Protist diversity and phylogeny
California Department of Fish and Wildlife
2019-2024
University of California, Berkeley
2012-2019
inStream Media (United States)
2017
Abstract Climate change and human pressures are changing the global distribution extent of intermittent rivers ephemeral streams (IRES), which comprise half river network area. IRES characterized by periods flow cessation, during channel substrates accumulate undergo physico‐chemical changes (preconditioning), resumption, when these rewetted release pulses dissolved nutrients organic matter (OM). However, there no estimates amounts quality leached substances, nor is information on underlying...
Abstract Intermittent rivers and ephemeral streams (IRES) may represent over half the global stream network, but their contribution to respiration carbon dioxide (CO 2 ) emissions is largely undetermined. In particular, little known about variability drivers of in IRES sediments upon rewetting, which could result large pulses CO . We present a study examining from 200 dry reaches spanning multiple biomes. Results standardized assays show that mean increased 32‐fold 66‐fold sediment...
Abstract Intermittent streams lose surface flow during some portion of the year and can be important breeding rearing habitats for stream biota. However, habitat contraction deteriorating water quality across summer result in harsh conditions mortality. We explored patterns drying a small intermittent Mediterranean‐climate California, including 4 years that differed antecedent precipitation. Wet–dry mapping revealed earlier fragmentation following dry winters entire sections varied their...
More than half of the world's rivers dry up periodically, but our understanding biological communities in riverbeds remains limited. Specifically, roles dispersal, environmental filtering and biotic interactions driving biodiversity are poorly understood. Here, we conduct a large-scale coordinated survey patterns drivers riverbeds. We focus on eight major taxa, including microorganisms, invertebrates plants: Algae, Archaea, Bacteria, Fungi, Protozoa, Arthropods, Nematodes Streptophyta. use...
We estimated dry season survival of imperiled salmonids in an intermittent coastal stream California across 4 years (2009–2012). Our study encompassed two and wet winters, allowing us to explore patterns within seasons with different antecedent precipitation. Apparent age-0+ steelhead trout (Oncorhynchus mykiss) was higher following winters compared winters. Moreover, precipitation positively correlated cumulative steelhead. Within years, apparent varied among weeks a tendency decrease the...
Omnivores can impact ecosystems via opposing direct or indirect effects. For example, omnivores that feed on herbivores and plants could either increase plant biomass due to the removal of decrease consumption. Thus, empirical quantification relative importance impacts is needed, especially invasive omnivores. Here we investigated how an omnivore (signal crayfish, Pacifastacus leniusculus) stream ecosystems. First, performed a large-scale experiment examine short-term (three month) crayfish...
Headwater and intermittent streams have traditionally been considered less biologically diverse than downstream perennial reaches. However, recent studies highlighted the significant role that headwaters play in supporting regional aquatic biodiversity. Additionally, Pacific Northwest may be more similar other regions. Here, we present a four-year biodiversity study of John West Fork, an coastal headwater stream northern California. It only flows for 5–7 months each year, but supports...
<title>Abstract</title> The lack of data from non-perennial rivers, which regularly cease to flow and dry up, poses a significant challenge in understanding river biodiversity. These dynamic ecosystems, accounting for over half the global network, remain understudied. To address this gap, we conducted coordinated experiment metabarcoding approach on environmental DNA targeting multiple taxa (i.e. Archaea, Bacteria, Fungi, Algae, Protozoa, Nematoda, Arthropoda Streptophyta). Dry sediments...
Abstract The magnitude, timing and duration of precipitation events can vary considerably across spatial temporal scales. In lotic ecosystems, such differences in patterns strongly influence water availability, which turn affects the population dynamics stream biota. Connectivity flow thresholds were developed for movement juvenile steelhead trout using hydraulic modelling 37 coastal California streams. Spatial spatiotemporal flows meeting threshold levels analysed long‐term gaging data....
Like other forms of commercial agriculture, recent work has shown that land use practices associated with cannabis