Landsat-based monitoring of an endangered beetle:  Addressing issues of high mobility, annual life history, and imperfect detection




Role of Geodata Crawler:
GeodataCrawler was used to process Landsat images, deriving numerous vegetation indices, and to quantify site characteristics from Landsat and soil GIS layers at various site radii around beetle trap locations.


Publication:
Leasure DR. 2014. Landsat-based monitoring of an endangered beetle: Addressing issues of high mobility, annual life history, and imperfect detection. Chapter 2 from PhD Dissertation: Applications of a New Geodata Crawler for Landscape Ecology: From Mapping Natural Stream Hydrology to Monitoring Endangered Beetles. University of Arkansas: Fayetteville, Arkansas, USA. 39 pp.

Funding Source:
Doctoral Academy Fellowship, University of Arkansas Graduate School
Arkansas State Military Department, Arkansas Army National Guard

Contribution to Education:
PhD. dissertation chapter by Doug Leasure at the University of Arkansas in 2014

Abstract:
A conservation priority for the endangered American burying beetle (Nicrophorus americanus) has been to implement habitat-based conservation, but its annual life history, strong dispersal ability, and low detectability have contributed to difficulties identifying manageable habitat characteristics and mapping the species’ current distribution. I assessed habitat within three site radii (100, 800, and 1600 m) to determine an appropriate spatial scale for habitat assessment of this mobile species. A Landsat time-series was used to quantify successional dynamics likely to be important for an annual species. Royle’s N-mixture model accounted for imperfect detection with baited pitfall traps, and was used to assess competing hypotheses that explained patterns of beetle abundance in western Arkansas. Factors hypothesized to affect beetle detection were temperature, dew point, wind speed, topographic position, and forest cover. Factors hypothesized to affect beetle abundance were vegetation structure, disturbance history, soil texture, and topographic wetness. Detection rates of N. americanus during our sampling periods averaged 0.20 ± 0.108 (± SD), and were dependent on overnight temperature, dew point, and wind speed. Results suggested upper and lower temperature thresholds beyond which detection was reduced. Habitat assessments were most effective within 800 m site radii, the estimated sample range of traps. Nicrophorus americanus abundance was associated with grasslands and open-canopy woodlands with rolling topography, sandy loam soils, and moderate patchy disturbances from wildfires or troop maneuvers. Large annual fluctuations in N. americanus population sizes were apparent, but availability of suitable vegetation communities appeared fairly stable. Results were consistent with the hypothesis that N. americanus populations have suffered from widespread losses of early successional communities. This project provided important conservation recommendations for an endangered species, demonstrated efficacy of Landsat-based monitoring, and provided a framework for assessing habitat of mobile annual species that are difficult to detect.

Professional Presentations:
2014 Invited Speaker, University of Nebreska-Kearney, Seminar in Biological Sciences, Kearney, Nebraska
2013 Arkansas Entomological Society Annual Meeting, Magnolia, Arkansas