DPI is Making a Difference in Southern Utah

Learning About Invasive Vs. Native Plants

Why it Matters

Although desert habitats often appear tough and virtually unchanging, in some ways nothing could be further from the truth.

The word preservation may bring to mind museum exhibits or fenced off landscapes, but for DPI preservation is about maintaining thriving, living environments.

why Is Tamarisk Such a Big Problem in the Southwest US?

Invasive plants like tamarisk are a threat on a national scale.

Across the U.S., invasive plants are estimated to occur on 7 million acres of our national park lands, and at least 1.5 million acres are severely infested. In addition to federal lands, state and private lands are also plagued with invasive plants and may have even higher infestation rates. This problem is an expensive one. The economic cost of invasive plants is estimated at more than $34 billion per year, and the costs continue to grow.

Tamarisk and other invasive plants can affect our economy, environment, and human health

An invasive plant is defined as a plant that is not native and has negative effects on our economy, environment, or human health. Not all plants introduced from other places are harmful. The term “invasive” is reserved for the most aggressive plant species that grow and reproduce rapidly, causing major changes to the areas where they become established.

Invasive plants affect land now, and for future generations.

Invasive plants, if left unchecked, will limit many uses on lands now and for future generations. Invasive plants can harm the natural heritage of our wetlands, prairies, forests, lakes, and rivers. Invasive plants can decrease your ability to enjoy hunting, fishing, mushroom collecting, bird watching, and other recreational pursuits.

The longer we wait, the more expensive it will be to control invasive plants. You can be a part of the solution by being aware of invasive plants and taking action to prevent their spread

Invasive plants make it harder to enjoy the outdoors.

Invasive plants can affect your ability to enjoy natural areas, parks, and campgrounds. Hikers, cyclists, and horseback riders all enjoy well-maintained trails, and invasive plants can grow over trails to the point that the path cannot be followed or can be difficult to navigate through.

What Science Says

To make a difference, we know that we must proceed using proven, effective methods based on research and the past experience of the many other conservation groups who seek to eradicate invasive species while maintaining the health of the plants and animals native to the region.
We have researched and compiled a list of successful projects in this region in order to draw on the best thinking and best practices of others invlved in similar restoration and revegetation projects.

Desert Preservation Initiative, in turn, shares our expertise and consults with other groups wishing to address the problems caused by invasive species in similar situations.

We have dug deep into the most successful practices for removing tamarisk, which includes the spraying of herbicide on cut stems within ten minutes of a cut being made.

One of our volunteers, Ken White, has done extensive research to create a toxicological review and risk assessment of the herbicide, ‘Pathfinder’.

In addition, we are in the process of creating a database of native and invasive plants in our area and of identifying those plants that would be most successful in restoration planting.

Internationally known botanist, Dr. Terrence Walters, has created a set of definitions of best terms for communication about nativity and non-nativity of plant species.

How We work

Work on invasive species removal projects requires careful planning to ensure the completion and success of the project and to monitor constant application of best safety practices in all field work. To accomplish these goals, DPI projects are divided into five phases:

Initiation

Removal

Monitoring

Restoration

Archival

Phase 1: Initiation

Projects are initiated as DPI volunteers and/or homeowners identify sites needing tamarisk removal. The Initiation Phase coordinator will initiate discussions with each property owner associated with the project as well as those might be impacted by the work and/or removal. Wherever HOA regulations and or other ordinances or concerns apply, the Initiation Coordinator will work with property owners to comply with, and file needed paperwork and secure written approvals.

Phase 2: Removal

The actual physical work begins in the Removal Phase when volunteers arrive to cut trunks and treat them with a growth hormone stimulator so that underground parts are killed. Debris removal is carefully managed according to plans that consider the slope and size of the site, existing native plants, drainage and access, and visibility to the public and property owners. Smaller debris may be chipped and left at the site. Larger trunks and branches are cut into short pieces and left on site or given to the Southern Utah Woodturners to make art objects for sale. The overall health of the site and the remaining native plants are documented for monitoring in the next phase.

Phase 3: Monitoring

Monitoring becomes essential as a team of volunteers takes on responsibility for visiting the site and recording changes every three months for the next 18-24 months. During the Monitoring Phase, volunteers locate and treat any regrowth of tamarisk, remove any invasive seedlings that have entered the site, record the ecological changes observed, including water and drainage changes, and record the growth of native plant species and signs of local fauna through time. Once the team has recorded two consecutive on-site reviews after the first six months with zero regrowths, long-term monitoring is handed over to the property owner.

Phase 4: Restoration Phase

Next, an on-site review is undertaken to evaluate the best options for restoration/replanting, as needed or possible, to make the site blend in as seamlessly as possible with the surrounding environment. In the Restoration Phase, site monitors determine if the project area can restore itself, in a reasonable amount of time, from:

Seeds produced from plants around the edges of the site
The existing seedbank of the previous native species in the area
New plants sprouting from existing underground rhizomes

If the coordinators believe the site could use some intervention to support and expedite its health and appearance, the Restoration Phase team will begin determining the species that should be purchased and planted. If planting appears to be necessary, the Restoration Coordinator will work with the project’s property owners for approvals and implementation, as needed.

Phase 5: Archival Work

Putting it all Together

Through the use of in-depth processes like our multi-phased work approach and a dedication to data-backed insights, we aim to achieve results as efficiently as possible in the field. By partnering with homeowners, local agencies, and fellow conservation groups, we expand the reach of our projects and multiply their impact.

Each step — from careful planning and safe removal to ongoing monitoring — ensures our work contributes to a healthier, more resilient watershed for generations to come.

If you’d like to be part of this difference, consider supporting our mission.

Help Us Preserve the Santa Clara River Watershed

Help us Preserve the Santa Clara River Watershed

Desert Preservation Initiative