Species-specific environmental preferences associated with a hump-shaped diversity/temperature relationship across tropical marine fish assemblages

TY - JOUR

T1 - Species-specific environmental preferences associated with a hump-shaped diversity/temperature relationship across tropical marine fish assemblages

AU - Clauson-Kaas, Anne Sofie Kjærulff

AU - Richardson, Katherine

AU - Rahbek, Carsten

AU - Holt, Benjamin George

PY - 2017/10

Y1 - 2017/10

N2 - Aim: To identify key environmental factors associated with local fish species richness across a large tropical marine region. Location: Wider Caribbean region. Methods: Species richness estimates were based on a sightings database covering the wider Caribbean region. Environmental variables considered were distance to key habitats, habitat area, temperature, depth, salinity, nutrient concentration, as well as natural and anthropogenic disturbance. We test the significance of associations between these factors and species richness, establish the shape of these relationships and use spatial cross-validation to test the generality of these results. Species-specific environmental associations within these relationships were then tested. Results: Five environmental variables showed significant associations with species richness, but only two, temperature and depth, proved robust to spatial cross-validation. Temperature was the best performing environmental predictor, showing a unimodal relationship with species richness and optimum temperatures consistent across analytical choices and data sets. Relationships between species richness and other environmental factors were also typically unimodal. Variation in species-specific temperature associations was significant within species richness gradients; with a higher number of species associated with optimal temperatures. Main conclusions: Temperature represents the dominant environmental predictor of fish species richness identified by our study, showing a hump-shaped curve, peaking at around 27.4°C. This meant that the warmest sites within our study were not necessarily the most species rich. Variation in species thermal niches may play a key role in driving species richness gradients, with significant general positive trend for fish species to occur in locations exhibiting optimum sea surface temperatures.

AB - Aim: To identify key environmental factors associated with local fish species richness across a large tropical marine region. Location: Wider Caribbean region. Methods: Species richness estimates were based on a sightings database covering the wider Caribbean region. Environmental variables considered were distance to key habitats, habitat area, temperature, depth, salinity, nutrient concentration, as well as natural and anthropogenic disturbance. We test the significance of associations between these factors and species richness, establish the shape of these relationships and use spatial cross-validation to test the generality of these results. Species-specific environmental associations within these relationships were then tested. Results: Five environmental variables showed significant associations with species richness, but only two, temperature and depth, proved robust to spatial cross-validation. Temperature was the best performing environmental predictor, showing a unimodal relationship with species richness and optimum temperatures consistent across analytical choices and data sets. Relationships between species richness and other environmental factors were also typically unimodal. Variation in species-specific temperature associations was significant within species richness gradients; with a higher number of species associated with optimal temperatures. Main conclusions: Temperature represents the dominant environmental predictor of fish species richness identified by our study, showing a hump-shaped curve, peaking at around 27.4°C. This meant that the warmest sites within our study were not necessarily the most species rich. Variation in species thermal niches may play a key role in driving species richness gradients, with significant general positive trend for fish species to occur in locations exhibiting optimum sea surface temperatures.

U2 - 10.1111/jbi.13044

DO - 10.1111/jbi.13044

M3 - Journal article

SN - 0305-0270

VL - 44

SP - 2343

EP - 2353

JO - Journal of Biogeography

JF - Journal of Biogeography

IS - 10

ER -