Songbird population trajectories diverge under simulations of conifer encroachment vs removal in a sagebrush ecosystem

Woody plant encroachment into grasslands and shrublands is a global phenomenon, negatively impacting ecosystem services and wildlife populations. North American sagebrush ecosystems have experienced widespread degradation from encroaching conifers, leading to losses of sagebrush-obligate wildlife. Removal of encroaching trees is a primary restoration method, but whether management actions can influence wildlife populations at management-relevant scales is rarely investigated. We studied a local Brewer’s Sparrow in the Medicine Lodge Valley of southwest Montana to understand how their territory occupancy and nest success were impacted by tree and shrub cover. From 2019-2022, our data collection resulted in 1,161 mapped territories and 449 nests, which we used to build models of territory occupancy and reproductive productivity relative to tree and shrub cover. We then used tree and shrub cover extracted from historical imagery to estimate population size and productivity 70 years in the ..., , # Data from: Songbird population trajectories diverge under simulations of conifer encroachment vs removal in a sagebrush ecosystem

Dataset DOI: [10.5061/dryad.9s4mw6mx2](https://doi.org/10.5061/dryad.9s4mw6mx2)

## Description of the data and file structure

We conducted this study at the sagebrush-forest ecotone in the Medicine Lodge Valley of southwest Montana, USA, during the breeding seasons of May-August of 2019–2022. We placed a 70 m square grid over the study site to quantify Brewer's Sparrow occupancy and predict population size under alternate scenarios. We collected vegetation data for each grid cell using remote sensing and estimated vegetation data under historic and two future scenarios. Vegetation data were used to model Brewer's Sparrow territory occupancy, nest success, and fledglings produced in each scenario (historic, current, future restoration, and future with no action).

### Files and variables

#### File: GriddedVegData.csv

**Description:** Relevant vegetation...,