ECOLOGICAL FACTORS as DRIVERS of MACRO and MICROEVOLUTIONARY PROCESSES in COMPLEX LANDSCAPES
Bioacoustics, Climatic Heterogeneity, Genetic Divergence, Isolation, Landscape Genetics, Macroecology, Macroevolution, Mountains, Speciation, Topographic Complexity
Mountain areas of the world cover less than 15% of global land surface; nevertheless, they concentrate around
90% of the hotspots of species diversity and 40% of the hotspots of endemism. Evidence suggest that factors such
as topographic complexity, climatic heterogeneity and their historical dynamics in mountains may play an important
role in the evolution and maintenance of their rich biotas. With my thesis, I aim to evaluate the role of such factors
in both macro (i.e. global speciation patterns) and microevolutionary (i.e. intra-specific genetic and trait
divergence) scales, using amphibians as study system. In the first chapter, I tested in a global scale the Montane
Pumps hypothesis, which proposes that speciation rates are faster in mountains explaining higher diversities in
those regions. To this end, I used a near complete Amphibian phylogeny containing 7238 species (>90% of extant
diversity) and conducted a Bayesian Analysis in Macroevolutionary Admixtures (BAMM) to estimate speciation
rates. Then I spatialized this information using available range maps to explore Amphibian geographic patterns of
speciation and evaluated its association with complex terrains by estimating a global index of topographic
complexity. I found that globally, speciation rates are faster in regions of high topographic complexity
independently of latitude. I deconstructed such pattern by repeating the analyses using the Wallace’s
Zoogeographic regions, taking into account regional independent evolutionary histories and found the same trend
in eight out of the total 11 zoogeographical realms. In the second chapter, I assess the relative role of different
components of the landscape in promoting lineage diversification across the roughed topography of Isthmian
Central America (ICA: Costa Rica & Panama), a geologically young but highly biodiverse region. Here I used
mitochondrial DNA to estimate genetic divergence within 11 amphibian species (9 anurans and 2 salamanders)
with different ecological attributes that co-occur in the region. Then, I use a Multiple Matrix of Regression with
Randomization and Generalized Dissimilarity Matrix analyses to quantify the relative role of isolation by distance,
environment and resistance (topography and suitability) in shaping geographic patterns of genetic structure within
each species. I have found idiosyncratic responses that may reflect specific aspects of their life histories and could
give insights on the role of ICA as engine of speciation. In the third chapter, I am testing how climatic and
topographic barriers may influence variation in advertisement calls, an important behavioral trait that have
species-specific features and may play a major role in species recognition and serve as a mechanism for
reproductive isolation. For this chapter I recorded advertisement calls of 221 males from 3 species of
Diasporus frogs distributed in Costa Rica. I made recordings at 30 sites across the country ranging from sea level
to 2800 meters elevation. I use this information to conduct bioacoustic analyses to 1.Document geographic
variation and 2.Test if geographic distance, physical or ecological barriers among populations, or adaptation to
local conditions could shape such patterns. To this end, I incorporate spatial analyses (niche models, terrain
roughness estimations and circuit theory) to generate levels of population isolation and apply Generalized
Dissimilarity Matrix test to address this question, this chapter is still in process.