Dornburg Alex

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Last Name
Dornburg
First Name
Alex
ORCID
0000-0003-0863-2283

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  • Article
    Disentangling the influence of urbanization and invasion on endemic geckos in tropical biodiversity hot spots : a case study of Phyllodactylus martini (Squamata: Phyllodactylidae) along an Urban Gradient in Curaçao
    (Peabody Museum of Natural History, 2016-10) Dornburg, Alex ; Lippi, Cat ; Federman, Sarah ; Moore, Jon A. ; Warren, Dan L. ; Iglesias, Teresa L. ; Brandley, Matthew C. ; Watkins-Colwell, Gregory J. ; Lamb, April D. ; Jones, Andrew
    Predicting the response of endemic species to urbanization has emerged as a fundamental challenge in 21st century conservation biology. The factors that underlie population declines of reptiles are particularly nebulous, as these are often the least understood class of vertebrates in a given community. In this study, we assess correlations between feeding ecology and phenotypic traits of the Lesser Antillean endemic Dutch leaf-toed gecko, Phyllodactylus martini, along an urban gradient in the Caribbean island of Curaçao. There has been a marked decline of this species in developed habitats associated with the invasive tropical house gecko Hemidactylus mabouia. We find a correlation between aspects of locomotor morphology and prey in undeveloped habitats that is absent in developed habitats. Analyses of stomach contents further suggest that Phyllodactylus martini alters primary prey items in developed areas. However, changes in prey promote the overlap in foraging niches between Phyllodactylus martini and Hemidactylus mabouia, suggesting that direct resource competition is contributing to the decline of Phyllodactylus martini. In addition to competitive exclusion, we suggest that the urban extirpation of Phyllodactylus martini could also be attributed to a top-down control on population growth by Hemidactylus mabouia. Colonizations of walls put Phyllodactylus martini in direct contact with Hemidactylus mabouia increasing the chances for predation events, as evidenced by our observation of a predation event on a Phyllodactylus martini juvenile by an adult Hemidactylus mabuoia. In total, our results add to a growing body of literature demonstrating the threat that invasive synanthropic reptiles pose to endemics that might otherwise be able to cope with increased urbanization pressures.
  • Article
    An assessment of sampling biases across studies of diel activity patterns in marine ray-finned fishes (Actinopterygii)
    (University of Miami - Rosenstiel School of Marine and Atmospheric Science, 2016-11-28) Dornburg, Alex ; Forrestel, Elisabeth J. ; Moore, Jon A. ; Iglesias, Teresa L. ; Jones, Andrew ; Rao, Leela ; Warren, Dan L.
    Understanding the promotion and regulation of circadian rhythms in marine fishes is important for studies spanning conservation, evolutionary biology, and physiology. Given numerous challenges inherent to quantifying behavioral activity across the full spectrum of marine environments and fish biodiversity, case studies offer a tractable means of gaining insights or forecasting broad patterns of diel activity. As these studies continue to accumulate, assessing whether, and to what extent, the cumulatively collected data are biased in terms of geography, habitat, or taxa represents a fundamentally important step in the development of a broad overview of circadian rhythms in marine fish. As such investigations require a phylogenetic framework, general trends in the phylogenetic sampling of marine fishes should be simultaneously assessed for biases in the sampling of taxa and trait data. Here, we compile diel activity data for more than 800 marine species from more than five decades of scientific studies to assess general patterns of bias. We found significant geographic biases that largely reflect a preference toward sampling warm tropical waters. Additionally, taxonomic biases likewise reflect a tendency toward conspicuous reef associated clades. Placing these data into a phylogenetic framework that includes all known marine fishes revealed significant under-dispersion of behavioral data and taxon sampling across the whole tree, with a few subclades exhibiting significant over-dispersion. In total, our study illuminates substantial gaps in our understanding of diel activity patterns and highlights significant sampling biases that have the potential to mislead evolutionary or ecological analyses.