Cost- benefit analysis of vegetation removal + seeding

Weighing costs relative to outcomes: woody and invasive plant removal followed by seeding in shrublands and woodlands.

Overview of a study conducted by the USGS, for full summary, please see https://www.usgs.gov/center-news/research-brief-cost-benefit-analysis-v…

Background:

The increase of undesirable woody and invasive plants on public and private lands elevates wildfire risk, alters habitat, and can lead to erosion. Expensive vegetation treatments are widely implemented each year and include removal of undesirable species and subsequent seeding. Despite these investments to improve ecosystem health, treatments are rarely evaluated to determine whether more spending improves intended outcomes. We assessed commonly employed vegetation treatments and costs relative to their outcomes across sagebrush shrublands and pinyon-juniper woodlands in the western USA. Our results give managers information on how money spent on various treatment combination relates to desired outcomes, and highlights the areas where more spending can yield better results. Given the growing need and costs of land management actions, we raise the importance of specifying treatment budgets and objectives and coupling this with effectiveness monitoring, to improve future efforts.

Summary of results

The following results are summarized in the table below.

If the desired outcome from a manager was to decrease woody plant cover, then spending more on either mastication + aerial seeding or harrowing + broadcast seeding yeilded better results. However, the mastictaion + aerial seeding treatment costed more than any other treatment for the best outcome. A double-pass with the harrow reduced woody plant cover for a longer period of time.

If the desired outcome was to decrease cheatgrass cover, then the herbicide + drill seeding treatment yielded the best results. The higher cost of applying a second application of herbicide was even better at reducing cheatgrass cover.

If the desired outcome was to increase perennial grass cover, then the herbicide + drill treatment or the harrowing + broadcast seeding treatments worked best. Also, spending money on removal treatments was better than spending this money on seed mixes and seeding treatments for this desired outcome.

If a manager's goal was to increase perennial forb cover and species richness, then the chaining + aerial seeding treatment was the best way to accomplish that goal. In addition, increased costs for this treatment was related to adding more species to the seed mix. The study found that the herbicide + drill treatment was a poor choice for this goal, as it reduced forb cover and species richness.