Evaluating Translocation Successes and Challenges: Case Studies of Federally Listed Plant Species of the Lake Wales Ridge, Florida
Stephanie Koontz, Archibold Biological Station, Cheryl L. Peterson, Bok Tower Gardens, Valerie C. Pence, Cincinnati Zoo and Botanical Garden, Eric S. Menges, Archbold Biological Station
Translocations are an increasingly utilized tool for rare plant conservation. Urbanization along the Lake Wales Ridge, in southcentral Florida, has led to 85% loss of native Florida scrub and sandhill. The few remaining intact patches hold a plethora of endemics. Our program has translocated several species from unprotected to protected parcels. All translocations are monitored post-outplanting and demographic data used to evaluate success. Here we present case studies for three federally listed species and discuss the challenges in restoring rare plants. Ziziphus celata has few remnant, mostly unprotected populations. Further contributing to its rarity is slow growth and limited sexual reproduction. We implemented 10 translocations between 1998 and 2012. Analyses of vital rates through 2016 determined annual survival of both wild and translocated plants is high (>90%), but growth of transplants is 1/10th the rate of wild plants. Many wild plants flower annually, yet <3% of transplants have reached reproductive maturity. Setting benchmarks for translocation success is challenging when dealing with a slow-growing, reproductively challenged species. Crotalaria avonensis has two protected and one unprotected site. Fruit set is low, requires insect pollination, and seedlings are rare. In 2012, we introduced genetic material from the unprotected site to a protected parcel. Transplants have thrived and expanded through clonal and seedling recruitment, from 84 original transplants to 208 plants in 2019. Germination of sown seeds was also a success (47%) with many surviving, flowering and fruiting. The first decade of this translocation may qualify as a success, but the ultimate test comes in long-term population responses to land management activities and climate change. Dicerandra christmanii has <10 sites, only one is protected. It relies on periodic fire to maintain open sandy gaps within the scrub matrix and persists from post-fire seedling recruitment. We have augmentated (2010) and introduction (2012) populations. Both translocations grew exponentially, but the question remained, were populations demographically viable. Using long-term demographic data from wild plants and integral projection models, we determined vital rates and predicted population trajectories were similar between wild and translocated populations. Wild populations provide a priori knowledge of a species’ basic biology and ecological requirements to inform more successful translocations.