Abstract Detail

Conservation Biology

Evans, Deveny [1], Scott, Austyn [1], Whitmore, Thomas [1], Riedinger-Whitmore, Melanie [1], Curtis, Jason H. [2], Cropper, Nicholas [1].

Long-term changes in aquatic plant communities in headwater lakes of the Florida Everglades: an application of conservation paleobotany.

The Kissimmee Chain of lakes are headwaters of the Florida Everglades, and they represent a freshwater network that contains more than twenty lakes in its entirety. Aquatic and riparian plants play an essential role in the biodiversity of freshwater ecosystems by providing protection and habitat for many invertebrates and fish. Aquatic plants also are crucial for sediment and shoreline stability, they assist in the oxygen supply in lakes, and they are an integral part of nutrient cycling. Long-term changes in aquatic-plant communities are largely undocumented, but paleobotanical methods can provide information to help with the conservation and protection of freshwater systems.
Lakes in the Kissimmee Chain were subject to significant hydrological alteration because the lakes were connected by canals and joined to the Kissimmee River by engineering activities in the 1880s. Hydrological changes continued during the 20th century. This resulted in substantial changes in aquatic plants and associated communities. We present the findings of a paleoecological assessment that documented these changes. We examined aquatic-plant macrofossils, pollen, plots of carbon/nitrogen ratios versus stable carbon isotopes, algal pigment analyses, and plant-related invertebrates to essentially “go back in time” and reconstruct the natural ecosystems before disturbance. This combination of data showed that major changes occurred in aquatic-plant communities in response to hydrological alterations and eutrophication. We determined that before the hydrological changes, there were frequent alterations in water levels and recurrent drier periods, as shown by the presence of high-solute communities and macrophytic remains that included Ruppia maritima, as well as solute-tolerant algae and zoobenthos. As high-solute tolerant communities disappeared, eutrophication was apparent with a transition to floating-leaf plants, such as Nymphaeaceae, after the disappearance of Chara because of progressive light limitation. For the macrofossil analyses, field work to collect reference samples proved important to the accurate identification of certain remains in the sediment.
Paleo-botanical research is an important tool for conservation biology, especially when there are no existing data for pre-disturbance conditions in ecosystems. With the application of historical ecological methods, we can better understand the ecosystems that we are trying to conserve, we can discover the biodiversity they held in pre-disturbance years, and can discover the cause of the changes in habitats. In addition, we can provide a more evidence-based approach to justify the needs of conservation and restoration, and the benefits they have for all of us.

1 - University of South Florida, Department of Integrative Biology, 140 7th Avenue S., St Petersburg, FL, 33701, United States
2 - University of Florida, Department of Geological Sciences, Gainesville, FL, 32611, USA

Keywords:
none specified

Presentation Type: Poster
Session: P1, Conservation Biology Posters
Location: Virtual/Virtual
Date: Monday, July 19th, 2021
Time: 5:00 PM(EDT)
Number: P1CB004
Abstract ID:326
Candidate for Awards:None