The responses of fauna, in terms of taxonomic composition and trait variability, to environmental and habitat changes in mesophotic ecosystems remain poorly understood, primarily due to the inaccessibility at depths from 30 to 200 m. This has led to a significant gap, especially on the associated fauna and their functional traits, which are essential for linking community structure to ecosystem processes. This study focused on epifaunal assemblages associated with Antipathella wollastoni forests across an east-to-west gradient in a subtropical oceanic archipelago. Dominated by amphipods, which comprised 92% of the total assemblage abundance, we analyzed their taxonomic structure and trait variability. We found an east–west gradient in body size (morphological) traits, with greater community-weighted maximum body size on the westernmost and central islands relative to the easternmost one, a pattern that was greatly enhanced when considering both inter- (among amphipod species) and intra-specific (individuals within a population) body size variation. Feeding traits also varied along this gradient, with amphipods adopting an animal-based diet on the easternmost island, whereas on the central and westernmost islands they presented a more plant-based diet, as a consequence of more diverse food sources. These dietary shifts may be linked to morphological adaptations, such as changes in the anatomy of gnathopods, likely a result of higher reliance on animal prey consumption. These findings highlight the adaptability of amphipods and the intricate relationships between morphological and trophic traits with habitat characteristics. This connection underscores the urgent need for more empirical research on the functional traits of invertebrates across environmental gradients. By pursuing such research, we can gain valuable insights that deepen our understanding of biodiversity and ecosystem dynamics, ultimately illuminating the critical roles these communities play in sustaining marine health and resilience.

Mesophotic “mentions”
11 x (total of 7859 words)

Classification
* Presents original data
* Focused on 'mesophotic' depth range
* Focused on 'temperate mesophotic ecosystem'

Fields
Biodiversity
Community structure
Ecology
Physiology

Focusgroups
Antipatharia (Black Corals)
Plankton

Locations
Spain - Canary Islands

Platforms
Rebreather