Semester Award Granted
Summer 2025
Submission Date
July 2025
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Thesis/Dissertation Advisor [Chair]
Erik Johanson
Abstract
This dissertation investigates late Holocene environmental change and human-environment interactions in Neotropical landscapes, focusing on two lake basins in Costa Rica: Laguna Carse in the southern Pacific lowlands and Laguna Arancibia in the Central Valley. Using high-resolution multi-proxy analyses, including pollen and both microscopic and macroscopic charcoal, we reconstructed vegetation dynamics, fire regimes, and basin processes over the past 1,500 years.
At Laguna Carse, a 400-year record reveals how regional population declines and colonial resettlement following the Spanish Conquest influenced land use, leading to delayed agricultural exploitation and subsequent vegetation disturbance. Pollen and microscopic charcoal analyses indicate periods of drought likely linked to the Little Ice Age, with episodic shifts in forest composition and fire regimes that reflect both climatic variability and human activities. The record captures the complex interactions between indigenous communities, colonial impacts, and climate, providing a fine-scale window into landscape change during a key historical period.
At Laguna Arancibia, a 1,400-year record shows persistently low fire activity and highlights the significance of geomorphic hazards, particularly landslides, in shaping settlement patterns. The sediment cores reveal a dynamic relationship between landslide events, sediment influx, and human occupation, suggesting that natural hazards influenced population movements and land use decisions. Pollen analyses further define distinct ecological zones derived from CONISS clustering, showing vegetation resilience to short-term disturbances yet vulnerability to compounded impacts from landslides and climate events like the Terminal Classic Drought.
Together, these studies demonstrate the intertwined roles of climate variability, natural hazards, and human agency in shaping tropical montane and lowland ecosystems in Costa Rica. The research reinforces the importance of paleoecological records for understanding vegetation change and long-term human-environment interactions. This research contributes to the broader understanding of vegetation resilience and vulnerability in tropical landscapes and offers valuable insights for contemporary land-use and conservation strategies in regions facing similar environmental challenges.
Recommended Citation
Friedel, Taber, "PALEOECOLOGICAL TRENDS IN COSTA RICA: NOVEL RECORDS OF VEGETATION, FIRE, AND HUMAN IMPACTS FROM HOLOCENE LAKE SEDIMENTS" (2025). Electronic Theses and Dissertations. 111.
https://digitalcommons.fau.edu/etd_general/111