Vincent Resh

University of California, Berkeley | UCB · Department of Environmental Science, Policy, and Management

The environment and its variability exhibit spatial heterogeneity in influencing ecological processes and community dynamics across landscapes. However, the mechanisms remain unexplored. This study investigates relative significance of temporal ecological processes that shape invertebrate community dynamics across 15 rivers in the European Iberian...

Cultures in Mediterranean climate zones (MCZs) around the world have long been reliant on groundwater and springs as freshwater sources. While their ecology and cultural sustainability are recognized as critically important, inter-relationships between springs and culture in MCZs have received less attention. Here we augmented a global literature r...

Global ecosystems are facing anthropogenic threats that affect their ecological functions and biodiversity. However, we still lack an understanding of how biodiversity can mediate the responses of ecosystems or communities to human disturbance across spatial gradients. Here, we examined how existing, spatial patterns of biodiversity influence the e...

The species-area relationship (SAR) is a well-established, globally recognized ecological pattern, and research on SAR has expanded to include the phylogenetic diversity-area relationship (PDAR). However, this research has generally been limited to terrestrial systems. Using data on freshwater macroinvertebrates, the log–log form of the SAR and PDA...

Species-level identifications of the larval stages of caddisflies are available for only a limited number of taxa that are used currently in water-quality monitoring programs. This has been a long-lamented condition, but the proportion of species identifications available for aquatic forms that are used in these efforts has increased little over th...

Examination of museum records indicate that 358 species of Trichoptera belonging to 83 genera and 20 families have been collected in California. The families Limnephilidae and Rhyacophilidae exhibited the greatest richness. Museums holding species records from California are listed, which enables localities to be obtained digitally or through museu...

Aim Both gene flow and genetic drift can affect the genetic diversity of interacting populations. However, the influence of the complex evolutionary histories of species may be obscured by simplified assumptions about how these roles operate in nature. To examine this issue, we mechanistically explored the relative importance of environment-mediate...

Most research on the ecological responses to extreme floods examines impacts at short time scales, whereas long-term datasets combining hydrological and biological information remain rare. Using such data, we applied time-series analysis to investigate simultaneous effects of a biotic factor (density dependence), an abiotic factor (extreme floods),...

An overview of the life and scientific accomplishments of Entomologist, Richard Garcia.

Insects are the most ubiquitous and diverse group of eukaryotic organisms on Earth, forming a crucial link in terrestrial and freshwater food webs. They have recently become the subject of headlines because of observations of dramatic declines in some places. Although there are hundreds of long‐term insect monitoring programs, a global database for...

The ability to prioritize habitats that have spatially varied contributions to species persistence can produce synergistic benefits for regional conservation efforts. However, conservation in spatially diverse landscape-networks requires considering dispersal asymmetry in the context of ecological connectivity and metapopulation persistence. By dev...

Aim Fractal networks, represented by branching complexity in rivers, are ubiquitous in nature. In rivers, the number of either distal (e.g. in headwater streams) or confluent (e.g. in mainstems) locations can be increased along with their branching complexity. Distal‐ or confluent‐spatial locations can result in fewer or greater corridor linkages t...

Different shapes of landscape boundaries can affect the habitat networks within them and consequently the spatial genetic‐patterns of a metapopulation. In this study, we used a mechanistic framework to evaluate the effects of landscape shape, through watershed elongation, on genetic divergence among populations at the metapopulation scale. Empirica...

Ecosystems in the Sacramento–San Joaquin Delta are changing rapidly, as are ecosystems around the world. Extreme events are becoming more frequent and thresholds are likely to be crossed more often, creating greater uncertainty about future conditions. The accelerating speed of change means that ecological systems may not remain stable long enough...

Stochastic (e.g., via species dispersal and ecological drift) and deterministic (e.g., via environmental and biotic filtering) processes can produce diversity patterns related to changes in elevation. However, existing studies have not generally examined these processes within a compressive framework. Stream macroinvertebrates are an important and...

A formal list of the caddisflies of California has not been published since 1956, at which time just over 170 species were included. Since then, the estimate of Trichoptera richness in the state has doubled. We used just under 7,000 digital records from online repositories and museum databases to compile a preliminary faunal list. To gain a broader...

Eric P. McElravy, an active researcher in Trichoptera and other groups of aquatic insects for 4 decades, died in San Leandro, California, on August 27, 2014. He was born on November 28, 1946, and raised in Ohio. He completed a Bachelor of Science and a Master of Science degree at Kent State University, and then spent 10 years as a high school scien...

The geographically widespread mayfly genus Baetis occurs from the subarctic to tropical regions of the world. Many of the 20 described Baetis species in North America are known to show cryptic species diversity. However, studies of Baetis that have examined morphology and genetic diversity have found mixed results in terms of cryptic species, with...

Macroinvertebrate communities occur in virtually all stream and river types worldwide. Only the most extreme and harsh conditions or where stream waters flow for only hours before drying are the members of this component of stream systems absent. Macroinvertebrates play a vital role in the ecology of stream ecosystems being responsible for much of...

Macroinvertebrates are used more often than any other groups of organisms when assessing the environmental quality of lotic systems. In this chapter we describe the many ways macroinvertebrates are used as indicators of environmental quality—from the molecular-through the community-level of biological organization. We highlight more recent advances...

Intermittent rivers and ephemeral streams (IRES) are common worldwide and play important roles in freshwater biodiversity and biogeochemical processes. Anthropogenic threats to IRES can be broadly classified into hydrological, physical, chemical, and biological alterations that can occur specifically during dry (e.g., sediment mining) or wet phases...

We investigated the influence and relative importance of insecticides and other agricultural stressors in determining variability in invertebrate communities in small streams in intensive soy-production regions of Brazil and Paraguay. In Paraguay we sampled 17 sites on tributaries of the Pirapó River in the state of Itapúa and in Brazil we sampled...

In a world of rapid environmental change, effective biodiversity conservation and management relies on our ability to detect changes in species occurrence. While long-term, standardized monitoring is ideal for detecting change, such monitoring is costly and rare. An alternative approach is to use historical records from natural history collections...

Glacial legacy, barriers to migration, and dispersal abilities are important determinants of intraspecific genetic diversity. Genetic comparisons can elucidate the distribution of genetic variants among populations, but for many groups of organisms the concordance of population genetic structure and historical refugia among co-occurring species rem...

Benthic macroinvertebrates show seasonal fluctuations with variability in hydrologic conditions. Coastal northern California (USA) is located in a Mediterranean-climate area, which is characterized by predictable wet and dry seasons, and consequently stream flows. Monthly sampling over multiple years (2004–2005, 2010–2013) was used to examine seaso...

Seasonal wetlands are important habitats for biodiversity of both invertebrate and vertebrate fauna. Many aquatic species have life history traits adapted to colonizing and developing in temporary aquatic habitats, and these traits influence the annual succession of the macroinvertebrate community. The chronology of taxon appearance and the variati...

The mayfly Baetis tricaudatus is an abundant, widespread, and ecologically important multivoltine benthic macroinvertebrate that is found throughout most of North America. Baetis tricaudatus belongs to the Baetis rhodani species group, which is known to have cryptic species. Some investigators have found that B. tricaudatus morphospecies have cytoc...

Variability in flow as a result of seasonal precipitation patterns is a defining element of streams and rivers in Mediterranean-climate regions of the world and strongly influences the biota of these unique systems. Mediterranean-climate areas include the Mediterranean Basin and parts of Australia, California, Chile, and South Africa. Mediterranean...

Limited studies have addressed how future climate-change scenarios may alter the effects of pesticides on biotic assemblages or the effects of exposures to repeated pulses of pesticide mixtures. We used reported pesticide-use data as input to a hydrological fate and transport model (Soil and Water Assessment Tool) under multiple climate-change scen...

The second volume in this landmark series includes an introductory chapter followed by 15 taxonomically specific chapters with identification keys to Nearctic freshwater invertebrates (protozoa through arthropods). Other than the second chapter's treatment of the diverse, multi-phyla array of protozoa (ciliates, flagellates, and amoebas), each of t...

Over the past 150 years dams have been constructed and water diverted from the Sacramento and San Joaquin Rivers to provide water for the San Francisco Bay area, the Central Valley and Southern California. Together with land reclamation and sedimentation from hydraulic mining practices during the gold rush, this has led to major changes in the delt...

A major challenge in the biological monitoring of stream ecosystems in protected wilderness areas is discerning whether temporal changes in community structure are significantly outside of a reference condition that represents natural or acceptable annual variation in population cycles. Otherwise sites could erroneously be classified as impaired. L...

Efforts to understand and predict socioecological systems in an historical context have increased. We investigated sinuosity patterns of roads and rivers to understand why the geometric design of roads and rivers corresponds to natural physical constraints in some regions but not in others. We hypothesized that, for physical reasons, the ratio of r...

Concentrations of 17 insecticides were measured in sediments collected from 53 streams in soy production regions of South America (Argentina in 2011-2014, Paraguay and Brazil in 2013) during peak application periods. Although environmental regulations are quite different in each country, commonly used insecticides were detected at high frequencies...

Freshwater invertebrates, including arthropods, molluscs, and other groups, provide both positive and negative consequences for human populations. These invertebrates are economically important as human food sources through their direct consumption and indirectly because they are important food for freshwater fishes. They are the most widely used o...

Water withdrawals and discharges from municipal wastewater-treatment plants in semiarid regions result in more urban streams becoming dependent on wastewater effluent for base flows. Such wastewater-effluent-dominated streams support perennial-stream ecosystems that would not otherwise exist. At the same time, ecosystems downstream of effluent disc...

Several species of fishflies (Megaloptera: Corydalidae: Chauliodinae) have been reported from intermittent streams in western North America, but the life histories and distributions of these species are poorly understood. We studied the life history of Neohermes filicornis (Banks 1903) for 2 years in Donner Creek (Contra Costa County, California),...

The recently completed Odonata database for California consists of specimen records from the major entomology collections of the state, large Odonata collections outside of the state, previous literature, historical and recent field surveys, and from enthusiast group observations. The database includes 32,025 total records and 19,000 unique records...

California Odonata database records after data processing, as described in methods.

Studies of landscape effects on assemblages and distribution of insects are relatively uncommon, largely because of the lack of occurrence data that span broad spatial or temporal scales. Here, we provide a multi-species analysis using generalized linear mixed models to examine the effects of local and regional variables on richness and occurrence...

Increases in water demand, urbanization, and severity of drought threaten freshwater ecosystems of the arid western United States. Historical assessments of change in assemblages over time can help determine the effects of these stressors but, to date, are rare. In the present study, we resurveyed 45 sites originally sampled in 1914–1915 for Odonat...

A calculation-theoretical procedure for estimation of the degree of blocking of laser emission by vapors of glass-reinforced plastic is represented with regard to the problem of laser cutting of this material. An example of the application of the procedure to the analysis of experimental data is considered.

Tolerance values (TVs) based on benthic macroinvertebrates are one of the most widely used tools for monitoring the biological impacts of water pollution, particularly in streams and rivers. We compiled TVs of benthic macroinvertebrates from 29 regions around the world to test 11 basic assumptions about pollution tolerance, that: (1) Arthropoda are...

Freshwater habitats in the western United States have experienced highly altered water quality, stream flow and sediment regimes in recent decades. Despite the relative lack of knowledge on the conservation status of freshwater organisms in the region, studies have documented extinction rates of this group to be on par with tropical rainforests. Od...

Although the California mediterranean climate region is widely considered a biodiversity hotspot for terrestrial plants and vertebrates, freshwater biodiversity in this region is generally not well known. Using information from museum specimen databases, published literature, biological assessment surveys, and specialist’s knowledge, we review fres...

Streams and rivers in mediterranean-climate regions (med-rivers in med-regions) are ecologically unique, with flow regimes reflecting precipitation patterns. Although timing of drying and flooding is predictable, seasonal and annual intensity of these events is not. Sequential flooding and drying, coupled with anthropogenic influences make these me...

As demands for freshwater withdrawals continue to escalate in water-stressed regions, negative consequences of alterations to natural systems will become ever more severe. Habitat restoration projects may mitigate some of these challenges, but new strategies will be needed to maintain or enhance ecosystem health while simultaneously meeting human n...

Tremendous opportunities exist for enhancing water quality and improving aquatic habitat by actively managing urban water infrastructure to operate in conjunction with natural systems. The hyporheic zone (HZ) of streams, which is the area of active mixing between surface water and groundwater, is one such system that is overlooked by many water pro...

Biomonitoring programs based on benthic macroinvertebrates are well-established worldwide. Their value, however, depends on the appropriateness of the analytical techniques used. All United States State, benthic macroinvertebrate biomonitoring programs were surveyed regarding the purposes of their programs, quality-assurance and quality-control pro...

Streamflow augmentation has the potential to become an important application of recycled water in water scarce areas. We assessed the economic and ecological merits of a recycled water project that opted for an inland release of tertiary-treated recycled water in a small stream and wetland compared to an ocean outfall discharge. Costs for the statu...

Identification of minimally disturbed reference sites is a critical step in developing precise and informative ecological indicators. We tested procedures to select reference sites, and quantified natural variation (inter-site and -annual variability) among reference conditions using a macroinvertebrate data set collected from 429 mediterranean-cli...

Long-term studies can document temporal patterns in freshwater ecosystems, and this is particularly important in mediterranean-climate (med-climate) regions because of strong interannual variation in precipitation amounts and consequently stream flow. We review long-term studies of populations and communities of benthic macroinvertebrate and fishes...

Overall biodiversity of freshwater ecosystems is declining at particularly high rates throughout the world as a result of land use, water use, and climate change. However, few studies have quantified changes in aquatic insect communities. In 2011 and 2012, we re-surveyed 43 sites that C.H. Kennedy originally sampled in 1914 for Odonata species to e...

We investigated interactions between the virulent trematode Ribeiroia ondatrae, which has been linked to amphibian malformations across the United States, and its amphibian host (Pseudacris regilla) using a hierarchical approach involving multi-year regional field surveys, replicated pond enclosures, and an unreplicated ecosystem manipulation of pa...

Large wood, both live and dead, is essential for producing complex habitat in many streams, especially in forested watersheds that support salmonid populations. The addition of engineered wood structures is a common approach taken in many streams where past watershed management practices have resulted in reduced wood loading. We examined six 300‐m...

Despite California policies requiring assessment of ambient wetland condition and compensatory wetland mitigations, no intensive monitoring tools have been developed to evaluate freshwater wetlands within the state. Therefore, we developed standardized, wadeable field methods to sample macroinvertebrate communities and evaluated 40 wetlands across...

Case-building is energetically expensive and case-repair may be a viable alternative to rebuilding for caddisflies when the case is damaged. In this study, we damaged the larval cases of 3 Trichoptera genera: Lepidostoma spp.; Neophylax rickeri Milne, 1935; and Onocosmoecus unicolor (Banks, 1897). We manually damaged the anterior, middle, or poster...

The limnephilid caddisfly Dicosmoecus gilvipies (Hagen) occurs in many streams of northwestern United States and British Columbia. Because of the large size of the fully grown larva, its synchronous emergence pattern, and its frequent imitation by fly-fishing anglers, D. gilvipes is one of the best known North American aquatic insects. Egg masses a...

Sampling variability in benthic studies may result from sampling device operation, physical features of the environment, laboratory sorting procedures, and biological features of study populations. Selected factors and procedures that influence variability, samplers affected, and proposed remedies are presented. Consequences of not considering aute...

A multivariate, predictive model based on the reference-condition approach is described for the Fraser River catchment in British Columbia. Benthic invertebrate assemblages and environmental descriptors were measured at more than 200 sites from 1994 to 1996, including 219 reference sites. Reference sites were classified into groups representing sim...

Biomonitoring requires thorough evaluation of methods used to detect impairment. Using a data set of 202 reference sites and 66 test sites from the Fraser River, British Columbia, Canada, we analyzed the effects of assemblage (benthic macroinvertebrates and periphyton) and reference site classification (ecoregion, stream order, null models, and bio...

Sequential decision plans provide a statistical approach that can reduce the number of benthic sample units needed to classify a site as impacted or unimpacted, thus reducing the cost of using benthic macroinvertebrates in water quality assessment programs. These plans require information about unimpacted and impacted conditions, the mathematical d...

Stream microcosms were used in situ to evaluate the separate effects of the thermal and chemical components of geothermal fluids from natural hot springs (which simulate accidental releases from geothermal energy developments) on benthic microorganisms and macroinvertebrates of Big Sulphur Creek, a third-order stream at The Geysers, Sonoma Co., Cal...

The 16 contributors who produced the 15 chapters in Robert Usinger’s Aquatic Insects of California (AIC), published by the University of California Press in 1956, included accomplished taxonomists experienced with aquatic insects, others who specialized in nonaquatic insect groups, and still others who were self-trained or worked in nonacademic pos...

Vineyards are a dominant feature of many landscapes in Mediterranean- climate regions. We examined the effects of streamflow declines, associated with vineyard water-withdrawals for frost protection, on benthic-macroinvertebrate communities at three sites along three small streams in the Mediterranean- climate region of Northern California. One sit...

This chapter describes classification, anatomy, morphology, physiology, reproduction, life history, phylogeny, evolution, ecology, and taxonomy of orders and families in which one or more life stages are truly aquatic and adapted for survival under or on the water surface. It also briefly mentions another arthropod group, the semiaquatic springtail...