DOI: 10.6073/pasta/41dac83a40c0e9dfc6515c2f95c7b534
title: Pika habitat occupancy survey data for Niwot Ridge and Green Lakes Valley, 2016 - ongoing

description: Long-term monitoring of habitat occupancy can reveal patterns of
  habitat use, population dynamics, and factors controlling species
  distribution. The American pika (Ochotona princeps), a small mammal
  found in rocky habitats throughout western North America, has been
  targeted for occupancy studies due to its relatively conspicuous
  behavior and its unusual adaptations for surviving long, cold winters
  without hibernation. These adaptations include an unusually high
  resting metabolic rate and maintenance of body temperatures near the
  lethal maximum for this species, which would appear to compromise the
  pika's ability to survive warmer summers. Recent monitoring as well as
  projections based on future climate scenarios have suggested this
  species is experiencing a period of range retraction due to warming
  summers and/or loss of insulating winter snow cover. Niwot Ridge is
  situated ideally to test competing hypotheses about the trajectory and
  drivers of pika range shift. The pika is still common throughout the
  Colorado Rockies, but published models differ markedly regarding
  projections of the pika’s future distribution in this region. Niwot
  Ridge has experienced warmer summers as well as shorter periods of
  insulating snow cover in recent years, and there is evidence that
  pikas are now less common than they once were in at least one area on
  the ridge. This study is designed to provide robust data on pika
  population trends through long-term monitoring of occupancy in a
  spatially balanced random sample of pika habitat patches centered on
  Niwot Ridge. Survey plots (n = 72) were selected according to a
  Generalized Random-Tessellation Stratified (GRTS) algorithm,
  stratified dichotomously by elevation, average annual snow
  accumulation (SWE), and probabilities of pika occurrence based on
  previous data. Each plot extends 12 m in radius from a GRTS point. To
  ensure that each plot contains at least 10% cover of talus, plot
  coordinates were adjusted (usually less than 50 m) or replaced using
  the GRTS oversample to select the next available and suitable plot
  within the same categories of elevation, SWE and probability of
  occurrence (see
  "pika-survey-GRTS-plot-tracking-record.cr.data.csv" for plot
  strata, survey schedules, GRTS sequence, and records of plot
  replacement or location adjustments). Trained technicians survey plots
  for pikas and fresh pika sign (food caches and fecal pellets) as well
  as metrics of habitat quality. Each year, 48 of the 72 plots are
  surveyed in a rotating panel design (24 plots are surveyed annually,
  24 in even years and 24 in odd years). Plots are surveyed in August
  when pikas are engaged in food caching and other conspicuous behaviors
  related to territory establishment and defense. Data collected at each
  plot are detailed in a survey manual
  ("pika_survey.cr.methods.docx"). Each plot is outfitted with
  a data logger (sensor) to record sub-surface temperature several times
  each day. Photos of plot and sensor locations are used in navigation
  and sensor retrieval. Each survey is completed during a brief
  (half-hour) visit to the plot to service the sensor and to record
  habitat and pika data. A subset of plots (n = 12) are selected for
  double surveys each year to allow estimation of pika detection
  probability. Estimates of detection probability are also informed by
  data on time to detection of pikas and pika sign recorded during each
  survey. Samples of fresh pika fecal pellets are collected from
  occupied plots and are stored as vouchers of pika presence and for use
  in studies of population genetics and physiology, including studies of
  physiological stress in relation to habitat quality and microclimate.