Give Me Shelter – Protecting Coastal Wetlands Through Habitat Assessment

Those who have spent time wading, or rather sinking, into the depths of marsh muds, maneuvering a kayak through fields of cordgrass, or casting a line where marsh transitions to bay, have surely appreciated the natural beauty of Texas’ coastal wetlands. These fields of salt tolerant grasses live at the intersection of terrestrial and aquatic habitats and fringe the shorelines of Texas bays. Their distinctive aroma signaling to visitors that they are transitioning into the tidal zone. Coastal wetlands provide an absorbent buffer against coastal wave action, stabilize shorelines from erosion, and lessen the impact of storm surge and floods. As one of the most diverse ecosystems in Texas, wetlands are home to a wide variety of plants and animals. If you enjoy catching fish in Texas bays, then you have reaped the benefits of a healthy coastal wetland.

Despite their ecological, recreational, and economic value, wetland habitats are disappearing at an alarming rate. It is estimated that Texas has lost more than 7 million acres, the equivalent of Dallas, Fort Worth, Houston, and San Antonio combined. One significant driver of this loss is rapid coastal development. Coastal development can destroy wetlands and exacerbate the effects of sea level rise. The compounding effects of sea level rise and coastal development shrink available land, altering natural wetland zonation (Figure 1). This loss of space impairs natural wetland function and degrades habitat quality. If we wish to continue successful fishing in our bays and to protect our shorelines for ourselves and future generations, we must balance development with the conservation of wetland resources.

One approach used to protect wetlands is the regulation of coastal development by the U.S. Army Corps of Engineers (USACE) through section 404 of the Clean Water Act and Section 10 of the Rivers and Harbors Act. These programs regulate construction and the discharge of dredged and fill material associated with coastal development activities into waters and wetlands. TPWD advocates for coastal wetland conservation through participation in the permitting process of coastal development. We use field habitat assessments to review the quality and quantity of fish and wildlife habitat proposed for impact and then provide recommendations to the USACE to minimize those potential habitat impacts.

Field habitat assessments are an evaluation of the biotic factors present in the wetland and an observance of the species using it as habitat. A productive, and sometimes muddy, field visit to a wetland involves the observation of species present to evaluate the functioning of the wetland habitat. Identifying what plant and animal species are inhabiting or using a wetland can also tell us how healthy the habitat is and if it has been disturbed by previous human activity. A healthy wetland will have a wide array of native species and adequate water exchange with a watershed. We can determine whether we are in low marsh habitat or high marsh habitat based on what plant species are present because wetland plant species distribution is influenced by the timing, quantity, and duration of water flow. For example, we know we are standing in low marsh when smooth cordgrass is present, because smooth cordgrass is a wetland plant species that occurs in areas with daily tides (Figure 1).

During site assessments, it is important to also observe fish and wildlife species utilizing the habitat for foraging, nesting, or cover to better understand the health and quality of a particular wetland. Lower quality, disturbed marshes will have fewer species using the wetland, whereas an abundant and healthy marsh is home to many species. We might observe fiddler crabs or stone crabs burrowing into the mud, or wading birds, like the snowy egret, patiently waiting to snatch small fish and invertebrates. Sometimes, we will see a mammal, like a deer, drawn in to feed on the leaves of marsh vegetation, or we may even spot a juvenile flounder or shrimp sheltering in the marsh as they grow.

Through our assessment of identified species and the role that they play in community interactions, we can use collected field data to understand the role that a specific marsh plays in an environment. This information strengthens our recommendations to avoid or minimize impacts to fish and wildlife habitat. If wetland loss cannot be avoided along the coast, there are steps we can take to ensure that the loss of important wetland habitat is accounted for. The Section 404 Program of the Clean Water Act requires developers to replace lost habitat with a habitat of similar function through restoration of a historical wetland, establishment of a new wetland, or enhancement or preservation of an existing one. The goal of these measures is to replace the lost wetland habitat with similar, high-quality fish and wildlife habitat. Thus, ensuring we will continue to have access to the beneficial resources that a lost wetland provided.

These regulatory review processes are an important component to the conservation of coastal wetlands and the values they provide along the Texas coast. Healthy coastal wetlands are essential habitat for the early development of many recreationally important fish such as red drum, spotted seatrout, and southern flounder. Therefore, we must consider how wetlands are impacted by development and how we can advocate for the conservation of wetland resources. Perhaps you will be inspired to get involved in local conservation efforts or attend public meetings regarding local development. The next time you are fishing near a marsh, take a closer look at this living, breathing ecosystem and appreciate its role in our ability to enjoy fishing along the Texas coast.