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Keyword: fish

Climate change and wildlife genetics

Science Spotlights Posted on: December 04, 2014
One of the biggest challenges that wildlife and plant populations face is the speed at which climate change is predicted to occur. For some species the rapid rate of change will outpace their ability to migrate to more suitable habitats. What is needed is an understanding of the evolutionary and genetic responses to climate change and accurate identification of which species will be unable to persist given various climatic predictions. Our research will help managers adjust to and reduce the negative impacts of climate change on ecological systems.

Distance, flow and PCR inhibition: eDNA dynamics in two headwater streams

Publications Posted on: September 11, 2014
Environmental DNA (eDNA) detection has emerged as a powerful tool for monitoring aquatic organisms, but much remains unknown about the dynamics of aquatic eDNA over a range of environmental conditions. DNA concentrations in streams and rivers will depend not only on the equilibrium between DNA entering the water and DNA leaving the system through degradation, but also on downstream transport.

Stream isotherm shifts from climate change and implications for distributions of ectothermic organisms

Publications Posted on: January 31, 2013
Stream ecosystems are especially vulnerable to climate warming because most aquatic organisms are ectothermic and live in dendritic networks that are easily fragmented. Many bioclimatic models predict significant range contractions in stream biotas, but subsequent biological assessments have rarely been done to determine the accuracy of these predictions.

Fish and other aquatic resource trends in the United States: a technical document supporting the Forest Service 2010 RPA Assessment

Publications Posted on: August 14, 2012
The Forest and Rangeland Renewable Resources Planning Act (RPA) of 1974 requires periodic assessments of the status and trends in the Nation's renewable natural resources including fish and other aquatic species and their habitats. Data from a number of sources are used to document trends in habitat quality, populations, resource use, and patterns of imperilment among aquatic fauna.

Native fishes of arid lands: a dwindling resource of the desert southwest

Publications Posted on: August 03, 2012
Includes color photos of 44 species of fishes, many published for the first time. Text describes aquatic systems in the mountains and deserts of the Southwest, the unique fishes they support, and habitats the fishes need.

Ribosomal DNA, heterochromatin, and correlation with genome size in diploid and polyploid North American endemic sagebrushes (Artemisia, Asteraceae)

Publications Posted on: November 30, 2010
Subgenus Tridentatae (Artemisia, Asteraceae) can be considered a polyploid complex. Both polyploidy and hybridization have been documented in the Tridentatae. Fluorescent in situ hybridization (FISH) and fluorochrome banding were used to detect and analyze ribosomal DNA changes linked to polyploidization in this group by studying four diploidpolyploid species pairs.

Validation of endoscopy for determination of maturity in small salmonids and sex of mature individuals

Publications Posted on: December 16, 2008
Fish maturity status, sex ratio, and age and size at first maturity are important parameters in population assessments and life history studies. In most empirical studies of these variables, fish are sacrificed and dissected to obtain data. However, maturity status and the sex of mature individuals can be determined by inserting an endoscope through a small incision in the body cavity wall and viewing the gonads.

Methods for evaluating stream, riparian, and biotic conditions

Publications Posted on: December 11, 2007
This report develops a standard way of measuring stream, riparian, and biotic conditions and evaluates the validity of the measurements recommended. Accuracy and precision of most measurements are defined. This report will be of value to those persons documenting, monitoring, or predicting stream conditions and their biotic resources, especially those related to impacts from land uses.

Implications of changing fire regimes for aquatic ecosystems

Publications Posted on: July 19, 2006
Climate change and past management, including fire suppression, have been linked to changing patterns of fire in the last century. It is widely believed that many forested areas have moved from a regime of low and mixed severity fire to more frequent and more continuous high severity fire (Hessburg and Agee 2003).

Species richness and patterns of invasion in plants, birds, and fishes in the United States

Publications Posted on: July 06, 2006
We quantified broad-scale patterns of species richness and species density (mean # species/km2) for native and non-indigenous plants, birds, and fishes in the continental USA and Hawaii. We hypothesized that the species density of native and non-indigenous taxa would generally decrease in northern latitudes and higher elevations following declines in potential evapotranspiration, mean temperature, and precipitation.