Temperature influences habitat preference of coral reef fishes: Will generalists become more specialised in a warming ocean?

Abstract

Climate change is expected to pose a significant risk to species that exhibit strong behavioural preferences for specific habitat types, with generalist species assumed to be less vulnerable. In this study, we conducted habitat choice experiments to determine how water temperature influences habitat preference for three common species of coral reef damselfish (Pomacentridae) that differ in their levels of habitat specialisation. The lemon damselfish Pomacentrus moluccensis, a habitat specialist, consistently selected complex coral habitat across all temperature treatments (selected based on local average seasonal temperatures naturally experienced in situ: ambient winter 22°C; ambient summer 28°C; and elevated 31°C). Unexpectedly, the neon damselfish Pomacentrus coelestis and scissortail sergeant Abudefduf sexfasciatus, both of which have more generalist habitat associations, developed strong habitat preferences (for complex coral and boulder habitat, respectively) at the elevated temperature treatment (31°C) compared to no single preferred habitat at 22°C or 28°C. The observed shifts in habitat preference with temperature suggest that we may be currently underestimating the vulnerability of some habitat generalists to climate change and highlight that the ongoing loss of complex live coral through coral bleaching could further exacerbate resource overlap and species competition in ways not currently considered in climate change models.

Dietary generalism accelerates arrival and persistence of coral‐reef fishes in their novel ranges under climate change

“…By definition, generalist species can cope with wider ranges of environmental conditions than specialists (Gilchrist, 1995), so our finding that the potential for establishment into new habitats is greater for the more flexible species is not surprising. However, the condition of generalism can be ascribed to a hypervolume of traits, each of which can differ in importance depending on a particular set of biotic and abiotic circumstances (Betzholtz, Pettersson, Ryrholm, & Franzén, 2013; Gilchrist, 1995; Kingsbury et al., 2019; Matis, Donelson, Bush, Fox, & Booth, 2018). Our models identified which traits and ecological mechanisms (i.e.…”

Predation avoidance and foraging efficiency contribute to mixed‐species shoaling by tropical and temperate fishes

“…Therefore, the behaviours and patterns presented here may not be the same for A. vaigiensis within its native range. Matis () demonstrated that vagrant Scissor tale surgeon Abudefduf sexfasciatus (Lacepede 1801), a congener of A. vaigiensis , formed mixed‐species groups when occurring as a vagrant in temperate south‐eastern Australia but only formed single‐species groups within its native tropical range. The author attributes these results to the behavioural plasticity of tropical fishes exposed to novel temperate environments.…”

Habitat complexity influences selection of thermal environment in a common coral reef fish

“… Richardson et al , 2018 , Roberts and Ormond, 1987 ) or changing temperatures (e.g. Donelson et al , 2010 , Habary et al , 2017 ) on reef fishes, few, if any, have considered how habitat availability may affect temperature choice and vice versa (see Matis et al , 2018 for exception). Understanding the nature and magnitude of the costs and benefits of associating with different habitat/s and thermal environments is crucial to predict how populations and distributions of coral reef fishes will respond to future conditions under ongoing ocean warming.…”

“…Indeed, the lack of suitable habitat has been suggested to constrain the poleward expansion of some reef fish species ( Feary et al , 2014 , Munday et al , 2008b ). The only other study we are aware of that investigated the effects of temperature on habitat choice of coral reef fishes suggested that exposure to 22, 28 or 31°C influenced habitat selectivity of three species of juvenile damselfishes, and although some differences were reported, the effect sizes were small ( Matis et al , 2018 ).…”