Fig 1.
A theoretical model illustrating the concept of ecological response diversity and how it can vary among locations and communities.
Each curve represents the functional response of a species (A-F) within a single functional group, e.g., herbivores or detritivores. Left: the functional responses of the three species are very similar, and response diversity is low. Right: functional response diversity is greater, and this community is likely to be more resistant to warming (in this case) or another type of disturbance or environmental change. Note the functional response of these species is often measured as metabolism or fitness. This can be informative, but it is often better to directly measure the species’ actual functional performance based on its specific ecological role, e.g., herbivory.
Fig 2.
The study species used in the predation experiments that quantified the effect of temperature on predation rates by four marine carnivores that inhabit rocky, subtidal reefs of the Galápagos.
(A) Heliaster cumingi, (B) Hexaplex princeps, (C) Tribulus planospira, and (D) Vasula melones. The three prey species used were (E) Megabalanus peninsularis, (F) Columbella haemastoma (note this image is of the visually very similar congener C. fuscata), and (G) Engina pirostoma. In the experiments, predator species A-C were fed Megabalanus and Vasula were fed the two small herbivorous snails (F and G). Species sizes, including their relative sizes, are not to scale. Photos A-D, F, and G were taken by Jose Vieira. E was taken by Favio Rivera.
Fig 3.
Recent benthic temperatures at Cerro Mundo reef, San Cristóbal Island, Galápagos at a 10 m depth.
Shaded areas of the graphic indicate the status of the ENSO cycle during the study period (El Niño red, La Niña blue, and neutral conditions in light grey) based on NOAA’s Oceanic Niño Index (ONI) https://www.climate.gov/news-features/understanding-climate/climate-variability-oceanic-nino-index). The four horizontal lines overlaying the temperature data are the estimated mean thermal optima for predation (as shown in Fig 4C) by the four experimental carnivores.
Table 1.
Summary of experimental temperatures, sample sizes, and durations for predator feeding trials.
Fig 4.
Effects of temperature on the respiration and predation of four common invertebrate carnivores found on shallow subtidal rocky reefs of the Galápagos.
A) Thermal Performance Curves (TPCs) for each species based on measurements of mass-normalized respiration across a range of temperatures. B) The thermal optima (Topt) of respiration across the four predators, calculated from the TPCs. C) Functional responses of predation to temperature. Vasula were fed two snail prey (Engina pyrostoma and Columbella haemastoma) and the other three predators were fed the barnacle Megabalanus peninsularis. In B and C, solid horizontal lines are mean values and associated vertical shaded bars are ± 1SE, while in A shaded bars are 95% confidence intervals. We fit curves for each species in C using the geom_smooth function in ggplot2 to help visualize the predation TPCs. See Supplementary Information for additional details about the predation experiments and respiration measurements.