Last updated: May 21, 2024
Article
Terrestrial Vegetation Monitoring 2019 Data Summary for Timucuan Ecological and Historic Preserve
Importance
Vegetation communities are dynamic entities whose species composition, abundance, distribution, and structure are influenced by environmental factors and impacts from natural and anthropogenic disturbances. The diversity of plants within the southeastern Coastal Plain 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 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 & 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. Bounded and monumented plots (20 × 20 meters [65.6 × 65.6 feet]) are used as the sample unit to determine a site’s (1) vascular plant richness and abundance (cover and frequency) for all native and non-native species; (2) woody stem abundance (basal area and density) and health for all native and non-native species; (3) density of forest floor fuels (along transects overlaying the vegetation plot); (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
Timucuan Ecological and Historical Preserve (TIMU) covers approximately 18,600 hectares (45,962 acres) and is located within the city limits of Jacksonville, Florida, between the St. Johns and Nassau Rivers. The park consists of large areas of salt marsh generally dominated by smooth cordgrass (Spartina alterniflora) and needlegrass rush (Juncus roemerianus), some freshwater streams, ponds, and wetlands, and adjacent uplands. The uplands are a mosaic of maritime hammock that contain species such as live oak (Quercus virginiana) and cabbage palmetto (Sabal palmetto); xeric hammock and coastal scrubs that contain sand live oak (Quercus geminata), saw palmetto (Serenoa repens), and rusty fetterbush (Lyonia ferruginea); and slash pine (Pinus elliottii) and restored longleaf pine (Pinus palustris) flatwoods. This protocol was implemented for the first time in Timucuan Ecological and Historic Preserve in 2019, and these data represent the baseline status of vegetation and associated abiotic elements from the following broadly defined habitats of the park: Maritime Upland Forests and Shrublands, Coastal Plain Nonalluvial Wetlands, and Coastal Plain Open Uplands and Woodlands. Twenty-three plots were established on these habitats within Cedar Point, Theodore Roosevelt, and Thomas Creek land parcels.
Significant Findings
Site and Environmental Factors
In the southeastern Coastal Plain, vegetation diversity is largely influenced by complex soil conditions and their associated relationship with site hydrology and disturbance patterns (e.g., fire). At Timucuan Ecological and Historic Preserve, these wide-ranging environmental conditions were observed in the landform, soil, and disturbance data collected from vegetation plots. Soil pH values ranged from 3.2 (acidic) to 7.1 (slightly alkaline) and topographic slope was variable in all but the Thomas Creek land parcel, where all slope values near 0°. Disturbances affecting vegetation composition differed across sites, with some form of disturbance noted in most plots. Historical and recent fire occurrences were observed in six of the 23 plots, including three plots sampled directly following the May-June Yellow Bluff Fire event. Other frequent disturbance events observed included windthrow and sites impacted by historical plowing.
Vegetation
Overall plot level plant richness ranged from 6 to 51 species. Species richness was lowest in sites most recently affected by the Yellow Bluff Fire. Diversity was highest in the Maritime Upland Forests and Shrublands habitat type, including overall richness (37) and richness across most growth forms (tree, vine, and herbs). Other noteworthy findings related to plant species diversity included:
- A total of 157 plant taxa (species or lower-level taxa) were observed across all plots, including nine species not previously known from the park.
- Frequently encountered species included muscadine (Muscadinia rotundifolia), cat greenbrier (Smilax glauca), saw palmetto, slash pine, gallberry (Ilex glabra), Darlington oak (Quercus hemisphaerica), Spanish moss (Tillandsia usenoides), and red bay (Persea borbonia).
- No species from the Florida Exotic Pest Council’s invasive plant list were observed during the 2019 monitoring effort. Our sampling effort did detect buckthorn bully (Sideroxylon lycioides), a state listed (Endangered) plant in Florida, on three plots within the Theodore Roosevelt land parcel.
- Total basal area of trees ranged from three to 53 m2/ha (570.5 ft2/ha), with the highest variability in Maritime Upland Forests and Shrublands. Common trees encountered were Darlington oak, red bay, live oak, slash pine, and cabbage palmetto.
NPS photo / M. Forbes Boyle.
Other Findings
- Both red bay and swamp bay (Persea palustris) were largely absent from the tree stratum across the park; however, they were present (occasionally in high abundance) in the seedling and sapling strata across all habitat types. Monitoring these plots over time will serve to track whether these species are recovering on the park following impacts from Laurel Wilt Disease.
- All plots were assigned to a community classification type, using NatureServe-defined vegetation associations. Several associations observed in Timucuan Ecological and Historic Preserve have special conservation value due to their region-wide rarity (Global Status Imperiled (G2) or Vulnerable (G3)). These included S. Atlantic Coastal Nonriverine Swamp Forests, Maritime Slash-Longleaf Pine Upland Flatwoods, Longleaf-Slash Pine Scrubby Flatwoods, S. Atlantic Coastal Shell Midden Woodlands, N.E. Florida Coastal Scrub, and Maritime Live Oak Hammocks.
- All plots are scheduled to be resampled in early summer 2023.
Full Report
The full report for Terrestrial Vegetation Monitoring at Timucuan Ecological and Historic Preserve 2019 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 & Publications
https://www.nps.gov/im/secn/reports-publications.htm
About the NPS Inventory & Monitoring Program
https://www.nps.gov/im/index.htm
Data Downloads via the Natural Resource Information Portal
https://irma.nps.gov/Portal/