Rarely are wildlife directly killed by a prescribed fire. Most wildlife are able to leave an area before it burns. Fossorial species retreat underground as the fire passes. However, there are some species, such as those that are less mobile, that are more susceptible to direct mortality. Generally, reptiles and amphibians are more at risk than mammals or birds. Fire can indirectly impact wildlife either positively or negatively by changing plant community composition and structure.
Does fire occur in wetlands?
Yes, many wetlands do periodically burn, both from wildfire and prescribed fire. Many wetlands are only seasonally wet, so they are susceptible to fire during the dry period. Fire can be used to alter the structure of vegetation in a wetland to meet certain management objectives. A specific example includes burning cattail mashes in the Northern Great Plains to benefit waterfowl. Also, periodic wildfire in the Everglades is important to remove accumulated peat from wetlands which allow for greater water depth during wet periods. These deep water areas are important for certain wildlife species such as the American alligator.
Managing Northern Bobwhite with Prescribed Fire
The northern bobwhite is a popular gamebird and many landowners wish to improve populations of this quail on their land. Practices such as timber thinning, disking, herbicide applications, and food plots are commonly implemented for bobwhites. However, prescribed fire is implemented by far fewer landowners. This resistance to use fire is unfortunate because fire benefits bobwhite more than any other practice.
Impacts of fire
Bobwhite require short, dense, woody cover (shrubs), perennial grass cover, bare ground, and abundant forbs (broadleaf herbaceous plants) with an open structure at ground level. Fire is an effective tool to manipulate all of these factors. Fire removes dead plant material, opens the structure of vegetation at ground level, and stimulates annual food-producing forbs to germinate. In a forest, fire can be used following a harvest or thinning that allows at least 50% sunlight into the stand. Burning these stands consumes leaf litter and stimulates a lush understory that provides better cover and more food, especially seed and soft mast.
Frequency
Fire frequency is the most important factor when using fire for bobwhite management. The ideal frequency depends on the plant community, precipitation, and soil type. In general, a short fire-return interval is needed in the eastern portions of the bobwhite range. Areas of the Gulf Coastal Plain may need fire every 1 – 2 years to maintain the early seral stages required by bobwhite quail in these areas. On the western edge of the bobwhite range where precipitation is much less, fire frequencies can be longer. Burning once every 10 years will maintain the plant community in a suitable composition and structure.
This pine savannah is burned every 1 – 2 years and is excellent bobwhite habitat.
Seasonality
Although fire frequency is the most important factor, season of fire can also be influencial. Fire in different seasons will tend to favor certain plants that may be more or less desirable for bobwhite. This is highly variable from place to place. However, in general, summer fires tend to reduce woody plant composition more than dormant-season fires. So, if your goal is to reduce woody plants and increase herbaceous plants, burning during the growing season should be considered.
Additional considerations
Similar to haying, burning during the nesting season can destroy nests. Most bobwhite nesting occurs May-July. So if growing-season fire is needed to control woody species, burning late in the growing season should be considered. Also, if a large area is burned in the spring, perennial grass cover for nesting will be lacking that year. Therefore, only a portion of the landscape should be burned in any one year. However, in areas that receive a lot of rain, such as the Gulf Coastal region, grass cover returns quickly following fire and quail may nest in that year’s burned area. Fire also temporarily removes shrub cover. However, most shrubs resprout and the resprouts are often more dense a year or two following fire.This further implies that only a portion of the landscape should be burned each year.
With a little experience and knowledge, landowners can effectively use prescribed fire to manage bobwhite habitat. Fire historically maintained healthy bobwhite populations and it can continue to do so today.
Managing Shrubs in the Southern Great Plains with Prescribed Fire
The southern Great Plains includes portions of Kansas, Oklahoma, Texas, New Mexico, and Colorado. This area is semi-arid grassland that is characterized by a highly variable climate. Within portions of this grassland, resprouting shrubs dominate on certain soil types. This is particularly true for sand sagebrush and shinnery oak which occur on deep sands. Other subdominant shrubs in this region include various species of plum and sumac. These shrubs provide various ecological services. Many species of wildlife rely on them for protective cover, thermal cover, and nesting cover, as well as for food resources. Northern bobwhite, Bell’s vireo, lesser prairie-chicken, and Cassin’s sparrow in particular are associated with shrubs in this region. Additionally, these shrub species are deep rooted and help stabilize soils from wind erosion from fires, as well as during the frequent droughts that characterize the variable climate of the Great Plains.
Direct Impacts to Shrubs
Often, managers wish to know how prescribed fire will affect shrubs. As with all grasslands, the southern Great Plains ecosystem evolved with fire. Thus, it is not surprising that the vast majority of shrub species within this region resprout from the root following a disturbance such as fire. Thus, fire will rarely result in mortality to the plant. However, fire does result in a temporary change in plant composition and structure. Following fire, many shrubs will be top killed. In other words, the above ground portion of the plant is consumed by the fire. The degree to which this occurs will depend on the fuel load, relative humidity, and other factors. Depending on rainfall following the fire, annual forbs (broad leaved herbaceous plants) and grasses tend to increase for the first 2 to 3 years following fire. In shrub dominated areas (sand sagebrush and shinnery oak), this impact is short-lived as the shrubs rapidly resprout and again dominate the site. Over time, the shrub stems will gain height and within 3 to 4 years sand sagebrush and shinnery oak will return to pre-burn conditions. Species such as sand plum will also resprout, but grow slower. This clonal shrub species grows in dense “mottes” where many stems are part of the same individual plant. The edge of the motte is often top killed by fire; while the interior remains unscathed (This will vary with fuel and conditions during the burn). Research has shown that sand plum mottes will increase in area over 330 square feet per year. Thus, depending on the original size of the motte, it may take several years following fire for this shrub to return to pre-burn conditions.
Associated Impacts
The change in plant composition and structure has dramatic impacts to wildlife species and also to livestock production. Wildlife species that require shrubs may be temporarily displaced until the shrubs dominate the site once again. Alternatively, other species which require higher amounts of grass and forb cover will increase on these burned areas for the first few years following a fire. The increase in grass production and crude protein of grass associated with prescribed fire will be attractive for livestock for 2 to 3 years following the fire. Thus, periodic burning in these shrub communities can be a valuable tool to increase livestock performance. However, due to the variable climate patterns, burning only a portion of a pasture in any one year is a good hedge against droughts. Some producers wish to use herbicides to eliminate shrubs in favor of grass to increase livestock performance. First there is no economic benefit to this or should increase in livestock production. It is also a risky practice in an area known for highly erodible soils. Thus, to maintain adequate root biomass for soil stability, and to ensure shrub obligate wildlife has adequate habitat, the use of periodic prescribed fire over portions of a pasture can be used by livestock producers.
Sand plum is a clonal shrub, where many individual stems are part of the same plant. This plant grows in dense “mottes” as seen in this photo. Fire often top-kills some of the stems along the periphery of the motte. However, large mottes generally are not completely top-killed but rather reduced in size by fire. Over time, this motte will expand by vigorous root sprouting stems.
This sand sagebrush plant community was burned 5 months prior to this photo. Notice the sand sagebrush resprouts across the pasture.
Shinnery oak is another clonal shrub that can have thousands of stems per acre. This photo depicts a recent prescribed fire (right portion of photo) and an unburned area (left portion of photo). Notice that the recently burned area is grass dominated. This is a temporary condition as shinnery will return to pre-burn conditions within 3 to 4 years post fire.