Benjamin H Letcher
Ben is a population ecologist focusing on stream habitats and science communication.
Biography
Education
- PhD, 1994, NC State, Zoology with statistics and modeling minor
- M.S. 1990, URI School of Oceanography, biological option
- B.S. 1985, Trinity College, Biology
Main research questions include:
Where are the fish?
- Distribution modeling
- Modeling climate refugia
What drives fish abundances?
- Long-term individual-based field studies
- State-space abundance modeling
- Integrated demographic models
How are the fish changing?
- Thermal adaptive capacity
- Estimating fitness in the wild
How are stream environments changing?
- Stream temperature statistical models
- Stream flow modeling using images
In addition, Ben is very interested in creating integrated, web-based systems to assist decision-making for natural resources. His group has created the Spatial Hydro-Ecological Decision System (‘SHEDS’ at ecosheds.org) which links databases, models and visualization tools.
- An extensive stream temperature database is at db.ecosheds.org.
- Stream temperature and Brook Trout occupancy models are at ecosheds.org
- The Interactive Catchment Explorer (‘ICE’) which facilitates exploration of complex environmental datasets and modeling results is at ice.ecosheds.org.
- Visualizations of individual tagging data from long-term studies are at pitdata.ecosheds.org.
- A stream visualization tool linking hydrographs to images is at fpe.ecosheds.org.
Google scholar link: https://scholar.google.com/citations?user=fwgbROwAAAAJ&hl=en
Link to CV
Science and Products
Climate change forecasts for eastern salmonids
Small streams in forests are likely to see dramatic shifts as global climate change influences air temperature and rain patterns. We have already seen warmer stream temperatures as air temperatures increase in summer in the Northeastern US. The intensity and duration of floods and droughts are also expected to magnify as future rain patterns shift. This project will evaluate how stream...
Fish Ecology
Our goal is to identify the factors that govern population dynamics. Emphasis is on an integrative approach, combining field and laboratory studies to provide data for mathematical models of ecological and evolutionary dynamics. We focus on the fish that live in streams; how environmental variation, barriers to movement, and landscape characteristics influence changes in abundance over time...
Predicting Climate-Induced Expansions of Invasive Fish in the Pacific Northwest: Implications for Climate Adaptation of Native Salmon and Trout
The headwaters of the Columbia River Basin in the Northern Rocky Mountains region is widely recognized as a stronghold for native fish, containing some of the last remaining connected cold-water habitats for species such as the threatened bull trout and native westslope cutthroat trout. However, as temperatures rise, non-native invasive fish species could be poised to prosper in the region as...
Modeling species response to environmental change: development of integrated, scalable Bayesian models of population persistence
Estimating species response to environmental change is a key challenge for ecologists and a core mission of the USGS. Effective forecasting of species response requires models that are detailed enough to capture critical processes and at the same time general enough to allow broad application. This tradeoff is difficult to reconcile with most existing methods. We propose to extend and combine...
State-space analysis of power to detect regional brook trout population trends over time
Threats to aquatic biodiversity are expressed at broad spatial scales, but identifying regional trends in abundance is challenging owing to variable sampling designs, and temporal and spatial variation in abundance. We compiled a regional dataset of brook trout Salvelinus fontinalis counts across their southern range representing 326 sites from...
Pregler, Kasey C.; Hanks, R. Daniel; Childress, Evan S.; Hitt, Nathaniel P.; Hocking, Daniel J.; Letcher, Benjamin H.; Kanno, Yoichiro A geostatistical state‐space model of animal densities for stream networks
Population dynamics are often correlated in space and time due to correlations in environmental drivers as well as synchrony induced by individual dispersal. Many statistical analyses of populations ignore potential autocorrelations and assume that survey methods (distance and time between samples) eliminate these correlations, allowing samples to...
Hocking, Daniel J.; Thorson, James T.; O'Neil, Kyle; Letcher, Benjamin H. The S.O. Conte Anadromous Fish Research Center--a model for progress
No abstract available.
Castro-Santos, Theodore R.; Haro, Alexander J.; Letcher, Benjamin H.; McCormick, Stephen D. Seasonal streamflow extremes are key drivers of Brook Trout young‐of‐the‐year abundance
To manage ecosystems in the context of climate change, we need to understand the relationship between extreme events and population dynamics. Floods and droughts are projected to occur more frequently, but how aquatic species will respond to these extreme events remains uncertain. Based on counts of Brook Trout (Salvelinus fontinalis) collected...
Blum, Annalise G.; Kanno, Yoichiro; Letcher, Benjamin H. Three visualization approaches for communicating and exploring PIT tag data
As the number, size and complexity of ecological datasets has increased, narrative and interactive raw data visualizations have emerged as important tools for exploring and understanding these large datasets. As a demonstration, we developed three visualizations to communicate and explore passive integrated transponder tag data from two long-term...
Letcher, Benjamin H.; Walker, Jeffrey D.; O'Donnell, Matthew; Whiteley, Andrew R.; Nislow, Keith; Coombs, Jason A hierarchical model of daily stream temperature using air-water temperature synchronization, autocorrelation, and time lags
Water temperature is a primary driver of stream ecosystems and commonly forms the basis of stream classifications. Robust models of stream temperature are critical as the climate changes, but estimating daily stream temperature poses several important challenges. We developed a statistical model that accounts for many challenges that can make...
Letcher, Benjamin H.; Hocking, Daniel; O'Neil, Kyle; Whiteley, Andrew R.; Nislow, Keith H.; O'Donnell, Matthew