Plant Succession: A Cornerstone of Wildlife Management
Managing vegetation is often the foundation of good wildlife management, and plant succession is a cornerstone of that foundation. Many wildlife biologists and managers will tell you that knowing your plants and how to manipulate them is a vital skill. Plant succession is one of the most important concepts to understand in order to manipulate the plant communities on your property to benefit wildlife species. The science of plant succession is a complicated one, and there is much variation between regions and ecotypes. This article is meant to serve as a primer for land managers who are interested in learning how they can use plant succession to their advantage.
Plant succession is the progression of different plant communities (seres) over time on a specific area (Ricklefs 2008). It starts with a disturbance, which can be caused by events such as wildfires or floods. These days natural disturbances such as fires and floods are often limited by human interference. Land managers usually need to create smaller scale, controlled disturbances in order to maintain plant communities in the successional stage that they want. Examples of manmade disturbances include prescribed fires, herbicide, disking, and grazing.
After the initial disturbance, the site progresses through several intermediate stages, or seres. The first plants to colonize a site after soil disturbances such as disking are normally annual forbs (weeds) and grasses. Over time, perennial forbs and grasses invade and out-compete the annual species. Woody shrubs and small trees often come next. These initial woody species are usually fast-growing, shade-intolerant species. Finally, a climax community typically composed of slow-growing shade-tolerant trees develops. The climax community is the final stage, and it only changes if subjected to considerable disturbances or environmental changes. This is the typical generalization that is used to describe succession in many areas of North America.
The actual successional stages that develop on a specific site do not always follow this pattern. Many variables including climate, soil types, local seed bank, and others may cause a site to skip certain stages or reach a climax community at an early stage. The ecoregion in which a site is located usually determines the climax community, but many sites differ from the climax community of the ecoregion due to slight variations in the variables mentioned above. The time span over which different stages develop is also highly dependent on local variables. On some sites it may only take a few decades to reach a climax community (e.g. prairie); other sites may take centuries or millennia to reach a climax community (e.g. old-growth hardwood).
The frequency and timing of disturbances, both natural and man-made, plays a major role in the progression of a site through successional stages. The time of year you disturb the landscape will determine what species you suppress and what species you promote (Harper and Gruchy 2009). This holds true for any type of disturbance –be it herbicide treatment, prescribed fire, or mechanical. The specific land management goals of the land owner will determine when a disturbance should be conducted. The frequency of the disturbance will determine at what successional stage the land is maintained. High frequency disturbances (usually 1–2 year interval) will maintain annual forbs and grasses; moderate frequency will maintain perennial forbs, grasses, and woody species (usually 3–5 year interval) (Harper and Gruchy 2009). The climate of a region will affect the required disturbance frequency. In eastern Texas, where rainfall is high, succession progresses rapidly and thus disturbances need to be more frequent than in the arid western part of the state.
A common species reliant on early successional habitat is the northern bobwhite (Colinus virginianus). Bobwhites need a combination of annual forbs for food, perennial grasses for nesting cover, and woody shrubs for escape cover (James et al. 2015). This means that bobwhite habitat needs to be managed simultaneously for several different stages of successional growth. The best way to promote multiple successional stages is by disturbing alternating strips or patches on a multi-year rotational basis (Burger, Harper and Gruchy 2009). The disturbance can be achieved with fire or disking. A recently disturbed site will have annual forbs as food sources while adjacent sites that were disturbed 2–3 years ago will have perennial plants such as bunch grasses that can provide nesting cover. When disturbing a site, make sure that you protect an adequate amount of escape cover (i.e. shrubs). There should be enough shrubs on the landscape that you can stand anywhere and be a softball throw away from a shrub. How often one rotates between burning or disking a site will depend on the climate of the region you are in. In eastern Texas, a site may require disturbance every couple of years, while western Texas landowners should probably wait every 3–4 years to re-burn or disk a site.
The following videos provide more information on using disturbances to manipulate plant succession:
- Disking for Quail Habitat in the Rolling Plains of Texas
- Disking for Wildlife Management
- Shredding/Mowing for Wildlife Management in Texas
- Grazing as a Tool for Managing Wildlife Habitat
- Proper Grazing of Quail Nesting Habitat
- Ragweeds & Quail
- Wildfires and Quail
- PatchBurn Grazing for Quail
- Prescribed Burning for Quail
Before implementing any intensive wildlife management plan, it is a good idea to consult a local wildlife professional. A wildlife professional will be able to assess your property to determine when and how to create disturbances to meet your specific wildlife management goals. To find a Texas Parks and Wildlife Department biologist click here, to find a Natural Resource Conservation Service office click here, and to find your County Extension Agent click here.
Funding support provided by the Reversing the Quail Decline Initiative and the Upland Game Bird Stamp Fund, based on a collaborative effort by Texas Parks and Wildlife Department and the Texas A&M AgriLife Extension Service.
Literature Cited
- Burger, W. Strip disking and other valuable bobwhite quail management techniques. Mississippi State University Extension Service. Publication 2032. Starkville, Mississippi, USA.
- Harper, C.A., J.P. Gruchy. 2009. Conservation practices to promote quality early successional wildlife habitat. Natural Resources Conservation Service, United States Department of Agriculture. Knoxville, Tennessee, USA.
- James, A.S., M. Marshall, B. Hayes, J. Hardin, R. Perez, J.C. Cathey. 2015. Habitat guide for northern bobwhite. Texas A&M University AgriLife Extension Service. Publication WF-020. College Station, Texas, USA.
- Ricklefs, R.E. 2008. The economy of nature. Sixth edition. W. H. Freeman and Company, New York, New York, USA.
Written by James Cash, Texas A&M WFSC ‘17
Originally published at wild-wonderings.blogspot.com.
