Forecasting rangeland plant production by ecological sites; are they better than forecasts by geographical location

Authors: Schantz, Merilynn; Hardegree, Stuart; Sheley, Roger; Bates, Jonathan - Jon; JAMES, JEREMY - California Polytechnic State University; ABATZOGLOU, JOHN - California Polytechnic State University; Davies, Kirk

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/23/2023
Publication Date: N/A
Citation: N/A

Interpretive Summary: n/a abstract only

Technical Abstract: Climate directly affects plant production across rangeland ecosystems. Forecasts of rangeland plant production could provide valuable management information pertaining to livestock stocking rates, restoration planning, wildfire fuel loads, and wildlife management. In the sagebrush steppe ecoregion, plant production is dependent upon climate but also varies by geographic location and the ecological site or dominant plant community. In this study, we combined retrospective seasonal climate forecasts and plant production models and compared these to plant production models driven by observed weather data across both geographical and ecological sites. This study was conducted in 45 intact late-seral sagebrush steppe sites over a 10-year time period across a 50,000 km2 area in southeastern Oregon. Research sites were sorted into five geographical groupings and into five ecological site groupings. The objectives of this study were to 1) model plant functional group responses to actual and forecasted climate across time and space; 2) Determine monthly plant production forecast skill for lead times of up to 7 months; and 3) Differentiate plant production model and forecast skill among both geographical site groupings and ecological site groupings. We found that plant production models and forecasts were able to identify key functional group responses to precipitation and temperature inputs. We also determined that climate and plant production forecasts could be used to produce significant monthly plant production forecasts for lead-times of up to 7-months for all site and functional groupings. We, furthermore, identified that forecasts of total plant production by ecological site groupings were significantly better than those that forecast from geographical site groupings. Forecasting by ecological site should, furthermore, lead to better rangeland management as it matches management inputs with inherent site conditions.