Reconstructing landscape scale vegetation in tropical Central America using bat guano carbon isotopes
Abstract
The humid tropics host most of the Earth's biodiversity and play an important role in global climate, but a paucity of tropical paleoenvironmental records makes it difficult to study how climate and the environment may have operated and influenced biodiversity in the past. Cave guano deposits, which can accumulate over millennia, represent an untapped paleoenvironmental archive in Central America that can provide context for modern-day biodiversity studies. In this pilot study, we used carbon isotopes measured in guano accumulations from insectivorous bats to estimate the relative abundance of C3 and C4 plants on the landscape in southern Pacific Costa Rica over the past several thousand years. We sampled material from two caves, Corredores and Gran Galleria, that host accumulations of guano from insectivorous Parnell's mustached bats (Pteronotus parnellii). To better contextualize our down-core results, we additionally sampled modern bat guano from the same caves and characterized the bats' modern diet by combining two complementary approaches: guano isotopic analysis and DNA metabarcoding. DNA metabarcoding provides a high resolution picture of the diversity of species consumed by bats, but not their relative abundances, whereas stable isotopes provide an overall view of diet, including inferences about relative abundance of food types. Our study provides historical context for several ongoing restoration experiments and a long-standing study on countryside biogeography by generating a more finely resolved picture of past forest coverage that will potentially advance contemporary conservation goals.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMPP42C..15R
- Keywords:
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- 0454 Isotopic composition and chemistry;
- BIOGEOSCIENCES;
- 0473 Paleoclimatology and paleoceanography;
- BIOGEOSCIENCES;
- 0491 Food webs and trophodynamics;
- BIOGEOSCIENCES;
- 4950 Paleoecology;
- PALEOCEANOGRAPHY