Next Steps for a Healthy Gulf of Mexico Watershed
Laguna Madre and Lower Rio Grande Valley
Landscape at a Glance
Located in the southernmost tip of Texas, along the U.S. border with Mexico, the Laguna Madre and Lower Rio Grande Valley form a complex mixture of both oceanic and riverine modified ecosystems. This focal area contains some of the fastest growing communities in the United States; produces significant crops (e.g., citrus); is a major nexus of international commerce with Mexico; and contains large, historic ranching operations. Natural resource-based tourism that includes hunting, fishing and natural history is a significant economic driver for the region. The international nature of the region, and its unique biodiversity, is important to Texas and the nation.
The focal area is semi-arid and subtropical in nature and represents a significant continental biodiversity hotspot for animals and plants. Native upland portions of the focal area are a mix of grassland savannas and Tamaulipan thornscrub. These native communities are important to the federally listed northern aplomado falcon that nests in the open grasslands, and endangered ocelots that live in the dense thornscrub. Additionally the Laguna Madre, one of only six hypersaline lagoons in the world, is located here and extends from South Texas into Mexico. Its expansive shallow seagrass beds are the winter home to more than 75 percent of the world’s population of redhead ducks, who also depend on nearby freshwater wetlands scattered amongst the landscape. In Texas, the Laguna Madre is protected by Padre Island, the longest barrier island in the world. Padre Island contains 361 square miles of wind-tidal flats, which support millions of wintering and migrating shorebirds, including the federally listed piping plover and red knots. The Gulf beaches of the island support the highest number of nesting endangered Kemp’s ridley sea turtles in the United States.
Native habitats in the focal area have been converted for agriculture or development, and remain at risk due to a rapidly growing population in the Brownsville area. Loss of coastal grasslands and native Tamaulipan thornscrub to invasive species, human encroachment and development present the greatest conservation challenge in this area. This habitat loss threatens northern aplomado falcon, mottled duck, ocelot and associated species. There is an urgent need for the Service and others to work together to protect additional native habitats, and to increase restoration capacity.
Enhancing the connectivity of the Laguna Madre landscape, particularly between thornscrub remnants on working ranchlands and conservation lands, will help maintain the nation’s only ocelot population, which occurs in Cameron and Willacy counties. The species’ recovery plan is currently under revision, and recovery criteria will include updated population and habitat targets once it’s finalized.
Just as ocelot recovery will depend on thornscrub connectivity between working ranchlands and habitat owned by conservation entities, northern aplomado falcon recovery will likewise be supported by grassland restoration efforts to restore similar connectivity. In order to reduce the risk of extinction and change the species’ status from endangered to threatened in the United States, 60 breeding pairs of northern aplomado falcon are needed. It is estimated that 30 breeding pairs could be supported in this focal area with successful grassland conservation and restoration. These grasslands also support populations of migrating and wintering buff-breasted sandpipers and long-billed curlews, whose winter habitat population objectives (20,599 and 11,031 individuals, respectively) have been established by the Gulf Coast Joint Venture.
Aquatic habitats in this region are equally important as terrestrial ones. Restoration efforts such as hydrologic diversions and development of wetlands are needed to meet the needs of targeted colonial waterbirds, shorebirds and waterfowl by providing vital food resources and forage fishery species. Aquatic habitat needs mesh well with objectives for numerous birds that have been established by the Gulf Coast Joint Venture: the reddish egret (1,650 breeding pairs); migrant shorebirds (e.g., >170,000 western sandpipers); midwinter mottled ducks (approximately 6,600 individuals); wintering waterfowl (including >392,000 redheads and >173,000 pintail); and other colonial waterbirds that use the Laguna Madre region.
The Gulf Coast Joint Venture has assessed seagrasses in this focus area relative to target waterfowl populations that utilize them as a food resource. While existing seagrass beds appear to be sufficient to meet waterfowl demands, if disturbance and/or lack of adjacent dietary freshwater renders 44 percent of seagrasses effectively unavailable, then habitat would become insufficient. The Gulf Coast Joint Venture has similarly assessed inland palustrine wetlands in this focus area relative to the needs of target waterfowl populations, and on average only two thirds of the approximately 18,000-acre winter habitat objective is met.
The beaches and associated habitats of the Laguna Madre are also important breeding sites for the U.S. population of Kemp’s ridley sea turtle and nonbreeding habitat for piping, snowy and Wilson’s plovers.
While many of the proposed actions in this focal area specifically list Service trust resource species as their targets, implementation of these actions will be advantageous to other species as well. For example, we place an overall emphasis on the restoration and enhancement of freshwater wetlands in order to meet the needs of colonial waterbirds, shorebirds and waterfowl. Those actions will also benefit aquatic species like largemouth bass, crappie and alligator gar through better water quality and increased habitat. Restoration of estuary habitats likewise will improve conditions for shrimp, blue crabs, oysters, red drum and other aquatic species. Restoring and conserving agricultural and working ranchlands will benefit not only Service trust resource species, but also many important state species like the northern bobwhite quail and the white-tailed deer.
High Priority Actions Based on the Service’s Vision
Restore and conserve agricultural and working ranchlands that complement and support the connectivity of land, invasive species control and water conservation efforts.
- Complete landscape assessment and species modeling for ocelots and northern aplomado falcons to develop habitat restoration priorities, including potential wildlife corridors, to meet recovery goals. Meet with other interest groups and see where conservation interests overlap.
- Identify and set habitat goals for target species within the focal area to be protected, restored or created.
- Support the delivery of Farm Bill programs through the U.S. Department of Agriculture (USDA) Natural Resource Conservation Service (NRCS) that are beneficial to wildlife, and restore or conserve target species habitats on agricultural and working ranchlands.
- Develop or participate in cooperative conservation projects with private landowners to help establish wildlife corridors or breeding areas on lands near, and between, important tracts of the Laguna Atascosa NWR that can contribute toward ocelot and northern aplomado falcon recovery objectives.
- Work closely with local municipalities and county governments to promote target species habitat conservation, maintenance and restoration. Continue to provide technical assistance on endangered species management to private landowners that includes a variety of methods such as habitat restoration guidance, signage, fencing, environmental education, outreach, community partnerships and law enforcement.
- Establish private-public partnerships that will result in beneficial translocation of ocelots to improve the genetics of small populations.
Enhance the existing network of conservation lands linking the Rio Grande River Valley and the South Texas coastal ecosystem to ensure that fish and wildlife resources are sustainable.
- Complete a Landscape Connectivity Assessment and decision-support tool for south Texas ocelots and use it to identify lands to support viable and self-sustaining ocelot populations.
- Coordinate land acquisition activities within the approved Lower Rio Grande Valley NWR acquisition boundary to establish coastal wildlife corridors from Boca Chica to Laguna Atascosa and to Northeastern Willacy County to strengthen connectivity between ocelot populations in those areas and protect existing and potential northern aplomado falcon habitat.
- Expand the network of perpetually conserved lands (via fee acquisition or conservation easement) linking the Rio Grande River Valley with other South Texas coastal ecosystems to establish wildlife corridors that connect to NWR lands and other conserved tracts needed to support ocelot and northern aplomado falcon recovery objectives.
- Support local partners working to implement specific management activities (e.g., vegetation management, predator control and human disturbance abatement) for bird-nesting rookeries, and create alternative colony sites designed to meet population objectives for colonial waterbirds.
- Install wildlife crossings that will protect ocelots from being killed by vehicles and will reduce wildlife-related accidents for motorists.
- Restore/enhance freshwater wetlands on conservation lands to meet population objectives for wintering waterfowl, mottled duck and migrant shorebirds.
- Protect through acquisition or active management, beach habitat on South Padre Island and Boca Chica Beach for nesting Kemp’s ridley sea turtles, peregrine falcons, and nesting and wintering shorebirds.
Reconnect hydrology and watershed diversions, such as the Bahia Grande, and restore wetlands and aquatic habitat for fish and other aquatic and wetland dependent species.
- Work with partners to complete engineering and permitting for remaining interior hydrology restoration projects of the Bahia Grande and seek funding for their implementation.
- Expand the pilot channel connecting the Bahia Grande Basin to the Brownsville Ship Channel to final design specifications to increase tidal exchange within the wetland system.
- Prioritize and assess the feasibility of additional hydrology restoration projects for multiple secondary bays or lakes such as San Martín Lake, El Tular Lake, Laguna Atascosa Lake, Bayside Lake and others.
- Restore the mudflat systems of sites like West Cayo and Horse Island by enhancing tidal flows and improving water management to benefit migrating shorebirds.
- Restore freshwater resacas (former channels of the Rio Grande) and associated wetlands on conserved lands by repairing water flow or control systems to restore and maintain natural flow to this wetland system.
- Continue to pursue opportunities for acquiring water through local irrigation districts to restore natural water regimes to repaired resaca wetland systems.
- Continue support of the Texas Parks and Wildlife Department and the Seagrass Monitoring Working Group to implement measures to protect and enhance seagrass habitats in the Lower Laguna Madre and Bahia Grande per the Seagrass Conservation Plan for Texas, benefitting redhead ducks and inter-jurisdictional fisheries.
- Support and participate in the implementation of action items of the Arroyo Colorado Watershed Protection Plan.