The response of big sagebrush (Artemisia tridentata) to interannual climate variation changes across its range

Abstract

Understanding how annual climate variation affects population growth rates across a species' range may help us anticipate the effects of climate change on species distribution and abundance. We predict that populations in warmer or wetter parts of a species' range should respond negatively to periods of above average temperature or precipitation, respectively, whereas populations in colder or drier areas should respond positively to periods of above average temperature or precipitation. To test this, we estimated the population sensitivity of a common shrub species, big sagebrush (Artemisia tridentata), to annual climate variation across its range. Our analysis includes 8,175 observations of year-to-year change in sagebrush cover or production from 131 monitoring sites in western North America. We coupled these observations with seasonal weather data for each site and analyzed the effects of spring through fall temperatures and fall through spring accumulated precipitation on annual changes in sagebrush abundance. Sensitivity to annual temperature variation supported our hypothesis: years with above average temperatures were beneficial to sagebrush in colder locations and detrimental to sagebrush in hotter locations. In contrast, sensitivity to precipitation did not change significantly across the distribution of sagebrush. This pattern of responses suggests that regional abundance of this species may be more limited by temperature than by precipitation. We also found important differences in how the ecologically distinct subspecies of sagebrush responded to the effects of precipitation and temperature. Our model predicts that a short-term temperature increase could produce an increase in sagebrush cover at the cold edge of its range and a decrease in cover at the warm edge of its range. This prediction is qualitatively consistent with predictions from species distribution models for sagebrush based on spatial occurrence data, but it provides new mechanistic insight and helps estimate how much and how fast sagebrush cover may change within its range.

Long‐term trajectories of fractional component change in the Northern Great Basin, USA

“…Fig. Secondly, it demonstrates that warming in cool sites creates a positive cover response, and vice versa in warm sites, similar to Kleinhesselink and Adler (2018) who reported that colder portions of the sagebrush range have a positive response in cover in warmer years, while warmer areas have a negative response. Cool WYTMIN sites have the greatest increase in WYTMIN, smallest increase in WYTMAX, and greatest decrease in WYPRCP (Fig.…”

“…5C shows that shrub and sagebrush cover increase in sites with the cooler average WYMIN below~17°C and decrease in warmer sites. 5C), again concurring with Kleinhesselink and Adler (2018). 5D).…”

Phenology and productivity in a montane bird assemblage: Trends and responses to elevation and climate variation

“…Demographic parameters are key among these because they provide a mechanistic link between population processes, climate covariates, and population dynamics (Grosbois et al, ). Studies that link demographic rates to climate are still relatively rare (Amburgey et al, ; Kleinhesselink & Adler, ; Scridel et al, ). We suggest that multi‐species demographic monitoring combined with directed research relating climate to demographic parameters can provide an important tool for guiding conservation of species assemblages in the face of climate change (Saracco, Fettig, San Miguel, Mehlman, & Albert, ).…”

Integrating anthropogenic factors into regional‐scale species distribution models—A novel application in the imperiled sagebrush biome

“…Our study species, big sagebrush, is a keystone species in the imperiled sagebrush steppe ecosystem (Miller et al, ). Prior studies have emphasized the role of climate and topography in determining sagebrush species distributions (Kleinhesselink & Adler, ; Schlaepfer, Lauenroth, & Bradford, ; Still & Richardson, ; Tredennick et al, ). However, sagebrush populations, especially in the Great Basin, are declining due to increases in fire frequency and are often additionally altered by intensive restoration efforts.…”