Southeastern Plants: Ecosystem Anchors Under Threat

Autumn at Meigs Falls, Great Smoky Mountains National Park.

NPS/Warren Bielenberg

Why Do Healthy Plant Communities Matter?

Youth join a ranger for a hike in Great Smoky Mountains National Park.

NPS

Plants are more than background scenery; they are the anchor in a healthy ecosystem. They form the foundation of the food chain, offering food, shelter, and nesting sites for wildlife. In the Southeast, these plant communities support a wide range of species like flying squirrels, black bears, tortoises, river otters, alligators, and various pollinators such as bees, butterflies, and birds.

In addition to supporting wildlife, plant communities benefit parks and people in many ways. They protect shorelines from extreme weather, filter water, cycle nutrients, stabilize soil, and sequester carbon, which are examples of processes known as ecosystem services. These services directly benefit people, providing cleaner air, safer shorelines, better flood control, and healthier spaces for recreation.

However, plant communities in the Southeast face significant challenges from invasive species, habitat loss, and rapidly changing climate conditions.

Invasive Species: A Growing Threat

Guinea grass (Megathyrsus maximus), which has long been a problem in South Florida and the Virgin Islands, is rapidly spreading in southern and central Texas.

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Texas tortoise (Gopherus berlandieri), the smallest tortoise in North America, in a habitat with invasive grass and native vegetation in the Gulf Coast Network.

NPS

Invasive species can crowd out and replace native plants, disrupting local ecosystems and harming biodiversity. One of the most aggressive invaders, Guinea grass (Megathyrsus maximus), has long been a problem in South Florida and the Virgin Islands and is increasingly spreading in southern and central Texas. NPS ecologists have documented its rapid expansion at Palo Alto Battlefield National Historical Park and San Antonio Missions National Historical Park, which are home to the state-threatened Texas tortoise. Annual surveys for Texas tortoises at Palo Alto Battlefield have revealed that there are fewer and fewer in areas that are most heavily invaded by Guinea grass, indicating that this invasive plant is reducing available habitat for the tortoises.

Early Detection: A Cost-Effective Management Strategy

NPS scientists collect data, identify newly emerging invasive plant species, eradicate small populations, and report larger infestations to one of the NPS’s Invasive Plant Management Teams (IPMT). The IPMT then can take action to mitigate infestations before they become widespread. Early detection and action save the federal government time and money in the long run by reducing the costs associated with more extensive management efforts and restoration needed for larger infestations.

In the Cumberland Piedmont Network, park staff partner with community science enthusiasts and use apps like iNaturalist to aid in the early detection of invasive species. These data inform and assist park managers in making science-based park management decisions. The South Florida Caribbean Network has a similar project in three parks including Biscayne National Park, where staff routinely look for potential new invaders in areas that have the highest chances of infestation, such as trails, waterways, boat launches and campgrounds.

Big South Fork National River and Recreation Area volunteer Debbi Exberger has documented more than 700 plant species on iNaturalist within the park, including 82 non-native plant species and over 100 new species for the park, as of August 2025. Through her collaboration with Appalachian Highlands Network biologists, verified new species are added to park species lists on NPSpecies. Sites with problematic invasive species are brought to wider attention as well. In this photo, a showy orchid (Galearis spectabilis) is documented, and while neither non-native nor a new species to the park, it is a charismatic orchid.

PHOTO COURTESY OF DEBBI EXBERGER

Florida Everglades ecosystem of a slough—a slow-moving, shallow water body typically found in wetlands. In this interdependent relationship, animals depend on plants for food, habitat and shelter, oxygen production, water regulation, and soil health.

NPS/Robert Hynes

Habitat Loss and Fragmentation

Within and around park boundaries, habitat degradation is possible. Altered hydrology, climate-driven changes, and other influences can all reduce the integrity of plant communities. Habitat loss reduces the space available for plants to grow, ultimately harming the health and resilience of plant communities. For example, the loss of freshwater sloughs and hardwood hammocks in Everglades National Park has contributed to declines in both plant and animal biodiversity. This decline can negatively impact native wildlife, such as threatened or endangered species like the Florida panther, manatees, crocodiles, and butterflies.

Rapidly Changing Climate Conditions

Across the region, shifting rainfall patterns, increasing drought, and rising temperatures affect plant health and their ability to regenerate. At Great Smoky Mountains National Park, for example, high-elevation spruce-fir forest communities depend on cooler conditions and cloud cover to thrive. When trees and other plants experience climate stress, they become more vulnerable to pests, invasive species, and even death. If the forest community can maintain its fog and cloud cover, there is hope for its survival. However, if conditions become drier and warmer with less fog or cloud cover, the future of this ecosystem may be uncertain.

Long-term monitoring of plant community condition supports the National Park Service mission to preserve natural resources unimpaired for future generations. By detecting ecological trends and stressors—such as invasive species expansion, habitat degradation, and climate-induced shifts—scientists provide park managers with actionable data to guide adaptive management and maintain ecosystem resilience.

This article is part of a series. Read more:

Rooted in the Southeast: Learning from Plants in Familiar Places

Shaping the Southeastern Park Experience: How Monitoring Plant Communities Makes a Difference

Southeast Vegetation Monitoring

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  Appalachian Highlands Network

  The Appalachian Highlands Network monitors rare plant communities called Cumberlandian cobble bars, or "river scour prairies".

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  Cumberland Piedmont Network

  Preserving forest vegetation communities is a priority for parks within the Cumberland Piedmont Network.

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  Gulf Coast Network

  Gulf Coast Network parks contain unique plant communities, from the diverse groundcover of pine savannahs to species-rich forests.

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  South Florida/Caribbean Network

  Forest communities are an important natural resource and cover a large portion of the park units of the South Florida/Caribbean Network.

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  Southeast Coast Network

  Over 3,000 plant species are distributed throughout 180 vegetation communities in the Southeast Coast Network.