The Scientific Research of Barry Tomlinson
Richards, J.H. , Troxler, T. G. , Lee, David .
Responses of Nymphaea odorata, Nymphoides aquatica, and Eleocharis elongata to water depth and dry down.
Early in his career, P. Barry Tomlinson was a researcher at Fairchild Tropical Garden in Miami, FL, where he wrote The Biology of Trees Native to Tropical Florida. Many of the trees he described are part of the historic ridge/slough/tree island landscape of the Florida Everglades. This wetland landscape is threatened by human activity that has altered the ecosystemís hydrology. Restoring the Everglades requires knowing speciesí hydrologic requirements in order to set restoration goals. In a two year mesocosm experiment on the response of three slough species (Nymphaea odorata, Nymphoides aquatica and Eleocharis elongata) to water depth (15 to 75 cm above shoot apices) and dry down, we found that these species showed differing morphological responses to both variables. N. odorata grew best in deeper water, producing fewer large leaves and investing relatively more biomass in leaves and roots; in shallow water it produced more small leaves and invested relatively more in rhizomes. This species produced miniaturized leaves in response to drydown and had reduced rhizome biomass compared to controls 4 months after water levels were raised. N. aquatica was less tolerant of deeper water but was similarly intolerant of drydown. This species had very different patterns of biomass allocation than N. odorata, investing more in roots and photosynthetic parts than in rhizomes. The emergent E. elongata had very different responses to water depth than the floating-leaved species. In deeper water this species could produce submerged photosynthetic shoots, at times in abundance, until shoots reached the surface, when these plants began to produce emergent photosynthetic shoots. E. elongata increased biomass and shoot production in shallower water, and increased this productivity even more with drydown. Thus, these three species have very different responses to both water depth and dry down. Maintaining all three in Everglades sloughs will require increasing water depths and duration, to support N. odorata, but also allowing for hydrological and/or topographic fluctuations to accommodate the other species.
This research was funded by Everglades National Park to answer questions about whether restoration plans would provide the conditions needed to restore the deeper water slough habitats in the Park. The results of this research have provided needed information to help set hydrologic targets that will be used to evaluate the success of Everglades restoration and are already being used to define slough performance measures in restoration.
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1 - Florida International University, Dept. of Biological Sciences, 11200 SW 8th St., Miami, FL, 33199, USA
Presentation Type: Symposium or Colloquium Presentation
Location: 552A/Convention Center
Date: Wednesday, August 4th, 2010
Time: 4:45 PM