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Invasive species are organisms moved from one region to another by humans. Although they are not always harmful to the recipient community, their lack of evolutionary history with their new community can set the stage for destruction. In a world of increasing interconnectivity and warming waters, we expect invasive species will continue to be introduced and that their ranges will expand as more areas become suitable habitats. At this critical point in our planet’s natural history, the need to understand where invasive species can survive and how to detect them are important. Here, I begin with a review of invasive species physiology measurements using species identified as invasive through the Marine Invader Monitoring and Information Collaborative. These data points highlight inconsistencies in measurement technique as well as the importance that acclimation temperature and life stage play on thermal thresholds. Based on the noise in the data, I recommend laboratory experiments to understand the absolute maximum and minimum survivable temperatures for each species, followed by field observations of temperatures needed to grow and reproduce. Then, using a newer invader to Maine Hemigrapsus sanguineus, I measured thermal thresholds for summer and winter-acclimated crabs and found shifts in thermal thresholds as well as evidence that winter temperatures are stressful for these crabs. Lastly, to effectively detect invasive species early, I tested and designed assays for environmental DNA (eDNA) detection of 9 invasive or nuisance species in the Gulf of Maine. Using laboratory experiments and a two-year time series in a local tide pool, I found that not all of the studied invertebrate species can be detected equally. Some organisms with soft, exposed tissues shed eDNA consistently with their abundance, while organisms with exoskeletons or shells do not. This trend does not hold true for all of the studied taxa, but this premise alongside an understanding of natural history and morphology helps clarify the observed trends. Thus, eDNA techniques should not be applied equally across all taxa for management purposes without a clear understanding of the message of the signal. Overall, I made recommendations to better predict suitable habitats for invasive species, characterized thresholds for an understudied invasive species in New England, and continued building upon the challenges of detecting invertebrates with eDNA.
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Herpetofaunal ecology (often) makes sense in the light of thermal physiology
An underlying rule in biology is that temperature affects physiological processes. This is salient in ectothermic organisms such as herpetofauna, which must cope with the challenges of changing body temperatures. The limitations associated with living in a dynamic thermal environment often translate into patterns of herpetofaunal distribution and behavior. As such, an understanding of thermal physiology and thermal environment are foundational to studies of herpetofauna. Beginning with a brief review of the contributions of Hal Heatwole and Hal Cogger to the field of thermal ecology, I explore how some methodologies and have changed over time with technological improvements to tackle emergent issues including invasion by herpetofauna and understanding of disease processes. I discuss recent applications of thermal ecology in my own research to understand and predict distribution of invasive herpetofauna, and to understand disease processes in wild populations. Specifically, I discuss the predictive value of critical thermal minima on current and future distributions of invasive lizards introduced to Florida, USA (Leiocephalus carinatus and Furcifer pardalis), obtained through different experimental and computational methods. I also discuss planned methodologies to assess the role of thermoregulation in combatting infection of Batrachochytrium dendrobatidis and B. salamandrivorans in plethodontid salamanders.
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- Award ID(s):
- 2109663
- PAR ID:
- 10398990
- Date Published:
- Journal Name:
- The 55th Scientific Meeting of Australian Society of Herpetologists
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
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- The DOI is not currently available.
