Here is a selection of our recent work. You can find a full list of Nick's publications here
Global Change Biology, March 2018
Payne NL, CG Meyer, JA Smith, JD Houghton, A Barnett, BJ Holmes, I Nakamura, YP Papastamatiou, MA Royer, DM Coffey, JM Anderson, MR Hutchinson, K Sato & LG Halsey
Being able to predict how temperature regulates species distributions is particularly important for mobile marine animals such as sharks given their seemingly rapid responses to warming, and implications of human encounters with some dangerous species. We combined catch data and accelerometry tagging to show that coastal abundance and swimming activity of tiger sharks Galeocerdo cuvierare both highest at ~22°C. Our combination of distribution and performance data takes a step towards a mechanistic understanding of tiger shark's thermal niche, and delivers a simple indicator that may be useful for predicting coastal occurrences of this potentially dangerous species.
Ecology Letters, January 2017
Payne NL & JA Smith
Ectotherms from higher latitudes can generally perform over broader temperature ranges than tropical ectotherms. This pattern is thought to reflect trends in temperature variability: tropical ectotherms evolve to be ‘thermal specialists’ because their environment is thermally stable. However, the tropics are also hotter, and most physiological rates increase exponentially with temperature. Using a dataset spanning diverse ectotherms, we show that the temperature ranges ectotherms tolerate (the difference between lower and upper critical temperatures, and between optimum and upper critical temperatures) generally represents the same range of equivalent biological rates (e.g. metabolism) for cool‐ and warm‐adapted species, and independent of latitude or elevation. This suggests that geographical trends in temperature variability may not be the ultimate mechanism underlying latitudinal and elevational trends in thermal tolerance. Rather, we propose that tropical ectotherms can perform over a narrower range of temperatures than species from higher latitudes because the tropics are hotter
Nature Communications, July 2016
Payne NL, G Iosilevskii, A Barnett, C Fischer, RT Graham, AC Gleiss, YY Watanabe
Animals exhibit various physiological and behavioural strategies for minimizing travel costs. Fins of aquatic animals play key roles in efficient travel and, for sharks, the functions of dorsal and pectoral fins are considered well divided: the former assists propulsion and generates lateral hydrodynamic forces during turns and the latter generates vertical forces that offset sharks’ negative buoyancy. Here we show that great hammerhead sharks drastically reconfigure the function of these structures, using an exaggerated dorsal fin to generate lift by swimming rolled on their side. Tagged wild sharks spend up to 90% of time swimming at roll angles between 50° and 75°, and hydrodynamic modelling shows that doing so reduces drag—and in turn, the cost of transport—by around 10% compared with traditional upright swimming. Employment of such a strongly selected feature for such a unique purpose raises interesting questions about evolutionary pathways to hydrodynamic adaptations, and our perception of form and function.
Biological Conservation, July 2016
Barnett A, NL Payne, JM Semmens & R Fitzpatrick
Wildlife tourism has been shown to cause behavioural changes to numerous species. Yet, there is still little understanding if behavioural changes have consequences for health and fitness. The current study combined accelerometry and respirometry to show that provisioning whitetip reef sharks (Triaenodon obesus) for tourism increases their daily energy expenditure by elevating activity levels during periods when they normally rest. Field metabolic rate increased by 6.37% on provisioning days compared to non-provisioning days. Since metabolism is a key parameter influencing most biological and ecological processes, this represents some of the clearest evidence to date that ecotourism can impact critical biological functions in wild animals.
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