Supporting rigor and management relevance in the collection, analysis, and interpretation of ecological data
I’m always finding myself working with great people on exciting projects. Here’s a sample of some recent collaborations:
Mojave desert tortoise connectivity: Seth is part of multiple projects assessing connectivity of Mojave desert tortoise populations. In response to roadkill mortality, major highways in the Mojave desert are usually equipped with exclusionary fencing to keep tortoises off of the highways. The downside to this protection is the prevention of connectivity for populations on either side of highways. Under-road culverts may ameliorate these barriers, but so far there are limited data on the effectiveness of culverts to connect populations across highways. Via mark-recapture, radio-telemetry, and simulations, Seth and colleagues are seeking to determine if culverts maintain connectivity and to identify the density of culverts needed to maintain a baseline level of long-term population connectivity.
Casey’s June beetle: In and around Palm Springs, California, is a tiny endangered beetle that emerges, mates, lays eggs, and dies all within a short window in the spring of each year. Seth is working with the U.S. Fish and Wildlife Service to quantify emergence patterns, factors affecting emergence, and patterns in latent abundance in Casey’s June beetles.
Raven abundance trends: Seth is working with the U.S. Geological Survey to analyze continent-wide trends in common raven abundance from 1966 to 2018. Raven populations have been known to have been increasing over time, with increasing intensity and spread of negative effects on populations of sensitive species, such as greater sage-grouse and Mojave desert tortoise. The results from this work will be used to develop management plans and actions to reduce the negative impacts of dramatic increases in raven populations.
Elk use of private vs. public lands throughout migration and seasonal ranges: Using data from GPS-collared elk, Seth assisted the Oregon Department of Fish and Wildlife in quantifying elk migratory behavior, migration seasons, and elk use of public and private lands throughout the year.
Dynamic bobwhite quail occupancy analysis: Seth is assisting a wildlife research non-profit with dynamic modelling of bobwhite quail occupancy over a 10+ period to assess the importance of vegetation cover on occupancy patterns and trends
Vegetative restoration success: Seth is the biometrician on a study investigating techniques for improving vegetation restoration success on abandoned oil well pads in Michigan. The focus is on identifying pre-planting treatments and tree species that maximize survival and growth of planted seedlings and on quantifying soil chemistry impacts of treatments.
Augmentary data: Seth recently published a manuscript evaluating the utility of using augmentary mark-encounter data to improve traditional radio telemetry-based survival estimates for resident and translocated desert tortoises. This technique will be useful for other small scale studies to improve the precision and estimability of survival of tagged animals.
Biodiversity hotspots: Seth recently gave a presentation on an analysis he did calculating biodiversity hotspots across Clark County, Nevada. The analysis provided high-resolution maps on biodiversity of species listed under Clark County’s Multiple Species Habitat Conservation Plan as well as a macroecological model for biodiversity of all plant, invertebrate, and vertebrate species.
Pronghorn migration: Seth recently collaborated with a state wildlife agency on a pronghorn migration analysis to better understand when and where pronghorn migrate across state, wildlife refuge, and hunting unit boundaries.
Desert tortoise: Seth recently developed a multi-year, multi-method occupancy model to identify landscape features associated with desert tortoise occurrence in the eastern Mojave desert. This is a novel statistical model that leverages the sparse information on desert tortoise occupancy and it has wide utility for other cryptic or highly-mobile species with high survival and/or territoriality. It incorporates multiple temporal levels of varying detection probability both within and among primary sampling seasons. This work was presented at the International Statistical Ecology Conference in St. Andrews, Scotland in June 2018.
Columbian sharp-tailed grouse: Seth spent time last winter contributing the statistical analysis portion of a project looking at sharp-tailed grouse hen and nest survival in CRP land versus native sagebrush steppe.
Kirtland’s warbler: Seth just wrapped up an analysis of point count data for endangered Kirtland’s warbler using unmarked N-mixture models to quantify detection rates and density of singing male warblers as a function of forest stand type. These results may identify new opportunities for conservation of Kirtland’s warbler breeding habitat.
Landscape disturbance models: Seth was part of a team that developed and tested the performance of distance and density-based landscape disturbance models to evaluate the relationship between cumulative human disturbances and greater sage-grouse populations and wetland and upland vegetation communities. This work was published in early 2017 (see Publications).
Custom R code: We were contracted to develop custom R code to automatically process hundreds of complicated GPS location text files and convert them to shapefiles. This will form the basis of upcoming analyses on spatio-temporal contact rates of hunters and white-tailed deer.
Greater sage-grouse: We are currently working on a meta-analysis of greater sage-grouse occurrence and fitness in relation to roads, particularly unpaved roads, to better understand inconsistent findings in the literature and provide guidance for land management.
Water quality: We have provided ongoing analysis and support on projects monitoring dissolved metals in surface and ground water to maximize the rigor of water quality monitoring projects in the Northern Rockies. In addition to conducting data analysis, our role was providing guidance on the most appropriate statistical tests to answer monitoring questions and explaining the inference that follows from the sampling design and data analysis.
Amphibian detection and abundance: Seth is analyzing survey data for amphibians in permanent forest pools in Illinois to estimate the detection probability and relative abundance of each species as a function of habitat type.
Migratory bird surveys: We regularly conduct field surveys to locate and monitor migratory bird nests as part of watershed-level cleanup of contamination from historic mining in the Northern Rockies.
White-tailed deer: We are providing ongoing advice on statistical analysis and interpretation with a study looking at how white-tailed deer behavior and movement is influenced by hunter density in Oklahoma.
Landscape types and breeding leks: Seth Harju presented a paper titled “Newly discovered greater sage-grouse leks: an analysis of multiple lek-supporting landscape types” at the annual meeting of the Idaho Chapter of The Wildlife Society in March, 2014. The talk described how, while investigating the likely origin of newly-discovered leks, Seth unexpectedly found that there were actually three distinct landscape types that supported sage-grouse breeding leks in Wyoming.
White-tailed deer body mass: Seth is part of a research team that just published a paper exploring environmental and innate sources of inter-individual variation in the body mass of white-tailed deer over two decades in Oklahoma.
Grouse reintroduction: We recently provided statistical and research oversight to a GIS-based study identifying suitable locations for reintroduction of sharp-tailed grouse to previously inhabited range in Washington and Idaho.
Legumes and grasses: We recently consulted on statistical analysis for a germination study of cool and warm season legumes and annual and perennial cool season grasses to identify optimal growing conditions in Oklahoma.
Complex habitats: Seth Harju presented a paper titled “Characterizing important seasonal habitat using community gradients: occurrence and success of greater sage-grouse broods” at the annual meeting of the Idaho Chapter of The Wildlife Society in March, 2013. The paper uses a multivariate approach to investigate how assemblages of vegetation and insects collectively function as habitat for sage-grouse broods in Wyoming.
Landscape connectivity: Seth Harju presented a paper titled “Generalized functional connectivity for animal populations” at the national meeting of The Wildlife Society in October 2012 in Portland, Oregon. The topic was describing a more flexible approach to assessing landscape connectivity, using data from greater sage-grouse (Centrocercus urophasianus) in Wyoming.