This file includes R code to select annual sampling units for nest survival analysis on the Arctic National Wildlife Refuge using a stratified random sampling approach.
We used the Generalized Random Tessellation Stratified (GRTS) procedure (Stevens and Olsen 2004) to obtain a spatially balanced sample of 28 plots in 2019 and 48 in 2022 within two of the four strata. In 2019, plots were equally allocated between wetland and moist strata, with 14 plots allocated to each. In 2022, additional plots were allocated to the moist stratum given the proportional availability on the landscape, with the final allocation being 30 moist plots and 18 wetland plots. We also selected an additional 20 “oversample” plots in each year, equally distributed among wetland and moist strata to replace plots that were found to be inaccessible during field operations. We restricted all nest survival plots to be > 1.5 miles apart.
The data providers have invested considerable effort in QA/QC, but it is possible that undetected errors remain. It is strongly recommended that careful attention be paid to the contents of the metadata file associated with these data to evaluate data set limitations, restrictions or intended use. The originators of this dataset shall not be held liable for improper or incorrect use of the data described and/or contained herein.
Potential users of these data should first contact the data authors listed below, as potential biases may occur within the data depending on the intended use. Therefore, potential users should contact the data authors to discuss intended use and how these data may or may not be applicable.
General field methods are available in annual protocol documents that detail specific annual methodologies.
