Last updated: May 21, 2024
Article
Terrestrial Vegetation Monitoring 2021 Data Summary for Chattahoochee River NRA
Overview
Vegetation communities are dynamic entities influenced by environmental factors and impacts from natural and anthropogenic disturbances. The diversity of plants within the southeastern Coastal Plain and Piedmont contributes to a range of ecological services, provides habitat and resources to an array of wildlife, and functions as nature’s backdrop—usually the primary visual cue pulling us toward an appreciation of the outdoors. Determining trends in vegetation communities over time and identifying plant stressors is therefore vital to understanding the ecological health of terrestrial ecosystems within Southeast Coast Network (SECN) parks. Collectively, this information can be used to guide management actions that sustain a park’s ecological integrity and support plant conservation across a diversity of spatial scales for generations to come.
Methods
The Southeast Coast Network collects long-term data on terrestrial vegetation within its parks using a peer-reviewed protocol similar to other NPS Inventory and Monitoring networks in the eastern U.S. and is modeled after the approach used to describe natural vegetation in the Southeast developed by the Carolina Vegetation Survey. Permanent plots are used as the sample unit to determine a site’s (1) vascular plant richness and abundance for all native and non-native species; (2) basal area, density and health for all woody species; (3) density of forest floor fuels; (4) community level disturbance events, including presence of insect pests and disease; and (5) abiotic condition (e.g., landform shape, soil nutrients, canopy coverage and height). Plots are randomly located across broadly defined habitat types within SECN parks. Our sampling effort focuses on dominant (> 30% coverage) habitat types within these parks, but when time and resources allow, the sampling effort is increased to include less dominant types. The 2019 Terrestrial Vegetation Monitoring Protocol provides detailed descriptions of field and data processing techniques used by the Southeast Coast Network.
Study Area
Chattahoochee River National Recreation Area (CHAT) occurs along a 77 kilometer [km] (48 mile [mi]) stretch of the Chattahoochee River north of Atlanta, Georgia. It is one of the largest urban parks within the U. S. and accounts for approximately 20% of the green space of metropolitan Atlanta. Within the park, the Chattahoochee River flows along the Brevard Fault Zone—a prominent geologic feature of the southeastern U.S. that separates the Outer Piedmont from the Inner Piedmont within Georgia and Alabama. The distribution and composition of forested habitats within the park are largely determined by former land-use patterns, as well as by localized edaphic conditions. Like most of the vegetated uplands across the Southern Inner and Outer Piedmont, the park’s uplands are dominated by a mixture of early-to mid-successional pine, oak, and mixed hardwood forests, while alluvial habitats are dominated by a variety of hardwoods that can tolerate periodic flooding and soils that remain wet for most of the year. This protocol was implemented for the first time at Chattahoochee River National Recreation Area in 2021, and these data represent the baseline status of vegetation and associated abiotic elements from the following broadly defined habitats of the park: Piedmont Alluvial Wetlands and Piedmont Upland Forests. Thirty plots were established across these habitats (see map).
Significant Findings
Site and Environmental Factors
Like most of the landscape across the southeastern Piedmont, the land that occupies the park has been subjected to profound impacts by humans following European settlement, including conversion of native forests to agriculture and timber land. Within the past century, increases in urban development around the park have had an additional impact on its forested resources. Urbanization is likely an important factor in contributing to invasive species spread in the park, and also serves as a deterrent for the use of fire to restore ecological processes. Fire exclusion over the past century has resulted in the decline in quality and extent of oak-hickory forests across Georgia’s Piedmont. Historically, the park’s drier ridgetops and gentle slopes undoubtedly supported fire-adapted ecosystems. Without fire, or other fire surrogate treatments, these forests likely will become dominated by a higher frequency of mesophytic, fire-intolerant hardwoods over time.
Vegetation
Two-hundred and ninety-nine plant species were observed across all plots. This included 29 taxa not detected in previous plant surveys and one species listed as rare and tracked by the Georgia Department of Natural Resources—large-fruited sanicle (Sanicula trifoliata). Overall plot-level plant richness ranged from 16 to 75 species, with trees and herbs providing most of the diversity to both broad habitat types sampled on the park during this monitoring effort—Alluvial Wetlands and Upland Forests. Non-native species were frequent across all plots and broadly defined habitats surveyed during this monitoring effort. Sixteen non-native species, categorized as invasive by the Georgia Exotic Pest Plant Council, were encountered on the park during this monitoring effort. Chinese privet (Ligustrum sinense) dominated the seedling and sapling strata of Alluvial Wetland habitat of these monitoring plots. Other invasive frequently encountered included Japanese honeysuckle (Lonicera japonica), Japanese stiltgrass (Microstegium vimineum), and Chinese holly (Ilex cornuta).
Other Findings
- The mortality rate of tree-sized green ash (Fraxinus pennsylvanica) observed within Alluvial Wetland habitats was high, and likely caused by impacts from infestation of the non-native emerald ash borer (Agrilus planipennis).
- The most dominant tree species within Alluvial Vegetation plots were tuliptree (Liriodendron tulipifera var. tulipifera), loblolly pine (Pinustaeda), boxelder (Acer negundo var. negundo), and river birch (Betulanigra); the most dominant species in Upland Forests were white oak (Quercus alba), lobolly pine, tuliptree, and mockernut hickory (Carya tomentosa).
- All plots are scheduled to be resampled in summer 2024.
Full Report
Terrestrial Vegetation Monitoring at Chattahoochee River National Recreation Area 2021 Data Summary
About the Southeast Coast Network
In 1999, the National Park Service initiated a long-term ecological monitoring program, known as “Vital Signs Monitoring,” to provide the minimum infrastructure to allow more than 270 national park system units to identify and implement long-term monitoring of their highest-priority measurements of resource condition. The overarching purpose of natural resource monitoring in parks is to develop scientifically sound information on the current status and long-term trends in the composition, structure, and function of park ecosystems, and to determine how well current management practices are sustaining those ecosystems.
The NPS Vital Signs Monitoring Program addresses five goals for all parks with significant natural resources:
- Determine the status and trends in selected indicators of the condition of park ecosystem,
- Provide early warning of abnormal conditions,
- Provide data to better understand the dynamic nature and condition of park ecosystems,
- Provide data to meet certain legal and Congressional mandates, and
- Provide a means of measuring progress towards performance goals.
The Southeast Coast Network (SECN) includes eighteen administrative areas containing twenty park units, fifteen of which contain significant and diverse natural resources. In total, SECN parks encompass more than 184,000 acres of federally-managed land across North Carolina, South Carolina, Georgia, Alabama, and Florida. The parks span a wide diversity of cultural missions, including four national seashores, two national historic sites, two national memorials, six national monuments, two national military parks, as well as a national recreation area, national battlefield, national historical park, and an ecological and historic preserve. The parks range in size from slightly more than 20 to nearly 60,000 acres, and when considered with non-federal lands jointly managed with the National Park Service, the network encompasses more than 253,000 acres.
For More Information
SECN Home Page
(https://www.nps.gov/im/secn/index.htm)
SECN Reports and Publications
(https://www.nps.gov/im/secn/reports-publications.htm)
NPS Inventory and Monitoring Program
(https://www.nps.gov/im/index.htm)
Data Downloads via the Natural Resource Information Portal
(https://irma.nps.gov/portal/)