Brush Management

By: Ian Witt, Wildlife Biologist - Sutton, Crockett, & Schleicher Counties

Land managers tend to focus on a specific wildlife species and its needs, as opposed to the habitat or community in which they live. A good strategy to use when managing wildlife species is a holistic approach which promotes overall healthy ecosystems. Aldo Leopold’s five tools of wildlife management (axe, plow, cow, fire, and gun) are key to managing natural resources in Texas by utilizing a holistic approach, with brush management (the axe) playing a crucial role.

Throughout the Edwards Plateau, plant communities have shifted from grasslands or savannahs to landscapes that are more heavily dominated by woody plant species such as mesquite, ashe juniper, redberry juniper, and prickly pear cactus. These are four of the most managed brush species in the Edwards Plateau region of Texas. The implementation of brush management practices including both mechanical and chemical applications, are essential to reducing canopy cover which ultimately increases plant diversity and allows for the establishment of desirable forb and grass species.

Mechanical applications of brush management practices include utilizing a tool or piece of machinery that aims to remove above and/or below ground plant material. Mechanical methods of treatment include grubbing, bulldozing, or the use of hydraulic shears on machinery. The mechanical technique used depends on the characteristics of the target species (will it resprout after treatment), amount of acreage being treated, access to equipment, topographical location, and soil types of the area being treated. Alternatively, chemical applications to manage brush species through herbicide can be used in many situations to achieve the same goals. Herbicides used to manage brush species can be applied using two main methods: Individual Plant Treatment (IPT) and broadcast/aerial application. The method of chemical application depends on the magnitude of the project, geographic location, and the species which is being targeted. With both mechanical and chemical applications, it is important to understand that different species require different methods of treatment and follow-up treatments may need to be implemented. Understanding how each species will respond, allows a land manager to make an informed decision to best meet land improvement goals.

A good brush management program should consider the habitat requirements of all wildlife species that are present by minimizing negative effects on any desirable plants in the area that may be an important habitat component. Targeted species can still be an important component of habitat; therefore, it is important to identify areas where complete removal of the target species might be detrimental to the end goal of the area being treated. Brush management techniques such as brush sculpting allow for maximized selectivity of the target species, while strategically “sculpting” the target area by using different treatment patterns such as blocks, strips, or a mosaic pattern across the landscape. In return, the sculpted habitat creates maximum edge which is desired by wildlife species and promotes plant diversity.

Contact your local wildlife biologist for more information on brush management or assistance with constructing and implementing a brush management program on your rangelands to help you reach your goals.

By: Erin Wehland, Wildlife Biologist - Western Lampasas & Burnet Counties

The wild turkey is an iconic game bird found throughout much of North America and occupy 223 of the 254 counties in Texas.  There are 3 subspecies of wild turkey in Texas with the Rio Grande subspecies being the most common.  Adult males average up to 20 pounds and females weigh ~10 pounds.  The home range of a turkey exceeds >500 acres with a flock occupying >5000 acres.  Turkey habitat consists of intermingled woody, brush, and opens areas that provide suitable places to roost, nest, and raise their young. 

Many hunters enjoy the challenge of luring in turkeys to harvest. Surveying and monitoring are necessary when a species is hunted to ensure that harvest is not having detrimental effects on the longtime survival of the population.  Trapping and banding operations and subsequent reports of hunter harvested turkeys are used to survey populations for disease and estimate harvest and abundance.  From 2015-2021, > 3000 Rio Grande Turkeys were banded in Texas using drop nets, walk-in traps, and rocket nets.  Before being banded and released, turkeys were sexed and aged using feather characteristics and blood samples are taken to test for disease.  Estimates from the data gathered projected a population of ~350,000 turkeys in the Edwards Plateau with an 8% harvest of male birds.  However, to keep estimates current, banding efforts are being renewed this winter. For more information about wild turkey management, please refer to the webpage, Turkey in Texas.

By: Chris Mostyn, Wildlife Biologist - Llano & Gillespie Counties

Hypogonadism occurs when a body does not produce enough of the hormone needed for growth and development. When a male white-tailed deer is hypogonadal the visible affects include abnormal antler growth, partial to no shedding of antler velvet, and partial or complete wasting away of reproductive organs. 

Unfortunately, what causes hypogonadism remains unknown. Multiple theories exist mostly involving what deer eat during different rainfall patterns suggesting the cause may be driven by range conditions. It is not well-established as to what the long-term impacts are of hypogonadism within a deer population, if any. Knowing the cause is the beginning not the end. More importantly knowing what causes this enables us the opportunity to manage it. Texas Parks and Wildlife Department launched a multi-phase project to finally answer this question. Phase one is underway using modern technology to again investigate where and how much hypogonadal deer exist to find areas of high concentrations. Subsequent Phases identify and develop methods to evaluation aspects of deer and land in these areas for analysis.

The socio-economic value of deer and deer hunting is vast and vital. The public deserves to understand the cause and what if any ways to address this condition for such a valued resource Texans enjoy so much. We need your help. If you see and have a picture of a deer with partially or fully covered antlers in velvet from October to March, please report this to your local biologist. 

By: Evan McCoy, Wildlife Biologist - Kerr WMA

During the 1970’s, by understanding the central components of fire (fuel, heat and oxygen) and its behavior, it became evident that fire could be manipulated. Relative humidity, fuel moisture, and wind speed were identified as factors directly related to fire behavior. Burning under a set of predetermined conditions to achieve a goal became known as prescribed burning.

In wildlife management, goals typically revolve around managing plant succession which can be altered with fire. Plants (forbs, grasses and woody vegetation) serve as the fuel to carry a fire. The moisture in plants fluctuates relative to humidity in the air and influences their ability to burn. Air temperature can alter fire behavior by drying out and preheating fuels which increases ignition. Wind speed affects the rate at which the fire spreads and can increase flame lengths. The time of year, grazing practices, and climatic conditions also affects fire. All these variables are incorporated into a fire prescription to ensure a safe and effective burn. 

For example: Burning dormant grass in January with 30% humidity, 60⁰ F, and winds at 10 mph can consume small ashe juniper without harming larger trees. However, you can change the prescription on this same site to burn more intensely and consume larger woody plants. For example: Burning green grass in September with 25% humidity, 90⁰ F, and 8-6 mph winds can more effectively burn through woodlands.

Regardless of the prescription, the bottom line is that plant communities have a predictable response to fire, and managers can manipulate fire to achieve the intended result. What type of prescription fits into your management goals? 

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