Multiple measures of thermal performance of early stage eastern rock lobster in a fast-warming ocean region

Abstract

To date, many studies trying to understand species' climate-driven changes in distribution, or 'range shifts', have each focused on a single potential mechanism. While a single performance measure may give some insight, it may not be enough to accurately predict outcomes. Here, we used multiple measures of performance to explore potential mechanisms behind species range shifts. We examined the thermal pattern for multiple measures of performance, including measures of aerobic metabolism and multiple as pects of escape speed, using the final larval stage (puerulus) of eastern rock lobster Sagmariasus verreauxi as a model species. We found that aerobic scope and escape speed had different thermal performances and optimal temperatures. The optimal temperature for aerobic scope was 27.5°C, while the pseudo-optimal temperature for maximum escape speed was 23.2°C. This discrepancy in thermal performance indicators illustrates that one measure of performance may not be sufficient to accurately predict whole-animal performance under future warming. Using multiple measures of performance and appropriate modelling techniques may lead to a more accurate prediction of future range shifts, in cluding the timing and extent of climate-driven species redistribution.

A cross‐scale framework to support a mechanistic understanding and modelling of marine climate‐driven species redistribution, from individuals to communities

“…Importantly, the individual level processes presented in Table 1 are often nested within higher levels, recognising the increasingly complex nature of climate change at community level. The tools presented in Table 1 can be used individually, but as more measures of performance are investigated, the better the understanding (Twiname et al 2019) and predictive capacity when they are incorporated into models.…”

“…An example of applying the above framework (Fig. 3c) was developed using the eastern rock lobster Sagmariasus verreauxi, which is a marine species suspected of undergoing a range extension in south-east Australia (Robinson et al 2015, Twiname et al 2019. We want to understand how this range extension will affect this species, and the existing lobster species within the area it is moving into, the southern rock lobster Jasus edwardsii.…”

“…(Nilsson andÖstlund-Nilsson 2008, Sørensen et al 2014). Other factors such as feed intake capacity (Fitzgibbon et al 2017), olfactory predator sensing (Dixson et al 2010) or predatory escape potential (Twiname et al 2019) may be more appropriate for predicting performance and overall survivability of other species or particular life stages. Importantly, fitness varies among individuals and populations and is key to providing adaptive opportunity to select for phenotypes better suited under novel conditions (Eliason et al 2011, Stitt et al 2013, Moran et al 2016.…”

“…normal activity levels, non-extreme environments) organisms have ample ways to increase their oxygen uptake, so that the uptake reflects need rather than the converse (Lefevre 2016, Lefevre et al 2017. When it comes to the aerobic scope, as a single measure of performance, new evidence shows that some species demonstrate aerobic scope increasing with temperature until death, and that other fitness related measures, such as growth, are optimised at different temperatures than aerobic scope (Clark et al 2013, Norin et al 2014, Verberk et al 2016, Fitzgibbon et al 2017, Twiname et al 2019. Even in models based on the OCLTT, fitness is predicted to be optimised at a lower temperature than aerobic scope due to ecological and life history trade-offs (Holt and Jørgensen 2015).…”

“…The inclusion of all traits into mechanistic models would require thousands of parameters and long computation time, rendering models intractable. (Fitzgibbon et al 2017, Twiname et al 2019).…”