Combining past and contemporary species occurrences with ordinal species distribution modeling to investigate responses to climate change

Many organisms leave evidence of their former occurrence, such as scat, abandoned burrows, middens, ancient eDNA, or fossils, which indicate areas from which a species has since disappeared. However, combining this evidence with present-day occurrences within a single modeling framework remains challenging. Traditional binary species distribution modeling reduces occurrence to two temporally vague states (present/absent), so thus cannot leverage the information inherent in temporal sequences of evidence of past occurrence. In contrast, ordinal modeling can use the natural time-varying order of states (e.g., never occupied vs. occupied in the past vs. currently occupied) to provide greater insights into range shifts. We demonstrate the power of ordinal modeling for identifying the major influences of biogeographic and climatic, variables on current and past occupancy of the American pika (Ochotona princeps), a climate-sensitive mammal. Sampling over 5 years across the species’ southernmo..., Our dataset includes n = 570 habitat patches surveyed by >1 of the authors and/or field technicians and determined to be currently occupied, previously occupied, or having no evidence of occupancy by the study organism, the American pika (Ochotona princeps). The dataset spans 5 years, from 2016 to 2020 inclusive. Latitude and longitude were recorded using hand-held GPS devices accurate to 2-7 m (WAAS-enabled), and “survey Year” is the year in which the site was most recently surveyed. “Ordinal status” is parameterized as 0 (no evidence of pika occurrence), 1 (old evidence of pika occurrence), or 2 (evidence of current pika occurrence). Binary status is given as either 0 (not currently pika-occupied) or 1 (current pika occurrence detected). Our study domain is divided into northeast, southeast, northwest, and southwest “sub-regions” of mountain ranges that are separated from each other by ~45-100 km of lower-elevation topography. We recorded “elevation” (in meters) using handheld GPS ..., , # Data from: Combining past and contemporary species occurrences with ordinal species distribution modeling to investigate responses to climate change

[https://doi.org/10.5061/dryad.z612jm6n0](https://doi.org/10.5061/dryad.z612jm6n0)

## Description of the data and file structure

Our dataset includes *n* = 570 habitat patches surveyed by >1 of the authors and/or field technicians. We identified talus or broken-rock habitat patches to survey using high-resolution imagery in CalTopo.com. In the field patches were determined to be currently occupied, previously occupied, or having no evidence of occupancy by the study organism, the American pika (*Ochotona princeps*). The dataset spans 5 years, from 2016 to 2020 inclusive. We utilized this data to assess how analyzing binary (currently occupied vs unoccupied) and ordinal (occupied vs historically occupied vs no evidence) may indicate different factors as being important to describe species distributions, over different timescales. We ...