COS 44-4 - Environmental controls on plant regeneration in drylands: Synthesizing data and models to support restoration seeding

Monday, August 7, 2023

4:15 PM – 4:30 PM PDT

Location: E145

Presenting Author(s)

GS

Gregor-Fausto Siegmund

Center for Adaptable Western Landscapes, Northern Arizona University; Southwest Biological Science Center, U.S. Geological Survey, United States

Coauthor(s)

DS

Daniel R. Schlaepfer

USGS Southwest Biological Science Center / Northern Arizona University
Flagstaff, Arizona, United States
DP

David Pilliod

Research Ecologist
U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center
Boise, Idaho, United States
AS

Allison B. Simler-Williamson

Assistant Professor
Boise State University, Department of Biological Sciences
Boise, Idaho, United States
MJ

Michelle Jeffries

US Geological Survey, Forest and Range Ecosystem Science Center
Boise, Idaho, United States
JB

John B. Bradford

Research Ecologist
USGS Southwest Biological Science Center, Arizona, United States

Abstract: Arid and semi-arid ecosystems are broadly distributed throughout the western United States, including the Great Basin and the Colorado Plateau. In these drylands, active restoration practices after disturbance or changes to land management often involve seeding with rangeland drills and aerial broadcast applications. Historically, restoration efforts are hampered by low and variable rates of plant regeneration from seed, leading to widespread transformation of native plant communities. For big sagebrush, past research has integrated long-lead, multi-month weather forecasts; ecosystem water balance models; and information about environmental requirements for plant establishment to produce forecasts for recruitment and establishment that inform restoration seeding decisions and are housed in the U.S. Geological Survey’s Land Treatment Exploration Tool.

Here, we expand this approach to support restoration seedings for a broader suite of priority forb and grass species. We present (1) a synthesis of existing knowledge about early life stages of species that are commonly used in direct seeding during restoration in the western United States, and (2) a framework for translating this information into models for plant establishment that can be used to forecast restoration seeding outcomes.

To create a reproducible and transparent synthesis, we developed a protocol to screen and collect data from a wide variety of studies on early plant life stages. We recorded the experimental design, seed source, and environmental variables used by each study to assess multiple components of plant establishment. Finally, we linked environmental variables to plant outcomes to summarize the effect of the environment on establishment. Using this approach, we screened 6354 articles on 23 priority restoration species that reported data on germination, establishment, survival, and growth from lab tests, growth chamber and greenhouse trials, and field experiments.

To develop methods to forecast establishment for our priority species, we surveyed existing models for plant germination, recruitment, and establishment. We compiled process-based and statistical models for plant establishment, and characterized the parameters and inputs required to derive predictions. Finally, we linked our syntheses of models and data to identify how observed relationships between environmental variables and establishment outcomes can be used in forecasts for plant establishment. Implementing these forecasts will leverage this synthesis and be the focus of future work. Collectively, our synthesis effort builds a database that will be used to describe patterns in research effort; to identify knowledge gaps; and to develop quantitative models that can enhance the effectiveness of restoration by natural resource management agencies.