Mapping of Land Cover with Open‐Source Software and Ultra‐High‐Resolution Imagery Acquired with Unmanned Aerial Vehicles

Abstract (from Remote Sensing in Ecology and Conservation): The use of unmanned aerial vehicles (UAVs) to map and monitor the environment has increased sharply in the last few years. Many individuals and organizations have purchased consumer‐grade UAVs, and commonly acquire aerial photographs to map land cover. The resulting ultra‐high‐resolution (sub‐decimeter‐resolution) imagery has high information content, but automating the extraction of this information to create accurate, wall‐to‐wall land‐cover maps is quite difficult. We introduce image‐processing workflows that are based on open‐source software and can be used to create land‐cover maps from ultra‐high‐resolution aerial imagery. We compared four machine‐learning...

Categories: Publication; Types: Citation; Tags: Birds, Drought, Fire and Extreme Weather, Fire, Grasslands and Plains, Landscapes, All tags... Northwest CASC, Plants, Southwest CASC, Wildlife and Plants, Fewer tags

Fire, livestock grazing, topography, and precipitation affect occurrence and prevalence of cheatgrass (Bromus tectorum) in the central Great Basin, USA

Cheatgrass (Bromus tectorum) has increased the extent and frequency of fire and negatively affected native plant and animal species across the Intermountain West (USA). However, the strengths of association between cheatgrass occurrence or abundance and fire, livestock grazing, and precipitation are not well understood. We used 14 years of data from 417 sites across 10,000 km(2) in the central Great Basin to assess the effects of the foregoing predictors on cheatgrass occurrence and prevalence (i.e., given occurrence, the proportion of measurements in which the species was detected). We implemented hierarchical Bayesian models and considered covariates for which > 0.90 or < 0.10 of the posterior predictive mass...

Categories: Publication; Types: Citation; Tags: Birds, Drought, Fire and Extreme Weather, Fire, Grasslands and Plains, Landscapes, All tags... Northwest CASC, Plants, Southwest CASC, Wildlife and Plants, Fewer tags

Bias in estimated breeding-bird abundance from closure-assumption violations

The closure assumption of many abundance models, that individual animals are present throughout the survey season, often is inconsistent with field data. The effects of closure-assumption violations on estimators of abundance and associations between abundance and covariates are not fully understood. Furthermore, one’s definition of abundance affects these estimates. We used simulated data on breeding birds to explore how permanent, non-random immigration and emigration that violate the closure assumption affect estimates from N-mixture abundance models and naïve models (models that do not account for imperfect detection). This is the first work to evaluate the effect of permanent immigration and emigration on estimates...

Categories: Publication; Types: Citation