Environmental optima for an ecosystem engineer: a multidisciplinary trait-based approach

Abstract

A complex interplay of biotic and abiotic factors underpins the distribution of species and operates across different levels of biological organization and life history stages. Understanding ecosystem engineer reproductive traits is critical for comprehending and managing the biodiversity-rich habitats they create. Little is known about how the reproduction of the reef-forming worm, Sabellaria alveolata, varies across environmental gradients. By integrating broad-scale environmental data with in-situ physiological data in the form of biochemical traits, we identified and ranked the drivers of intraspecific reproductive trait variability (ITV). ITV was highest in locations with variable environmental conditions, subjected to fluctuating temperature and hydrodynamic conditions. Our trait selection pointed to poleward sites being the most physiologically stressful, with low numbers of irregularly shaped eggs suggesting potentially reduced reproductive success. Centre-range individuals allocated the most energy to reproduction, with the highest number of intermediate-sized eggs, whilst equatorward sites were the least physiologically stressful, thus confirming the warm-adapted nature of our model organism. Variation in total egg diameter and relative fecundity were influenced by a combination of environmental conditions, which changed depending on the trait and sampling period. An integrated approach involving biochemical and reproductive traits is essential for understanding macro-scale patterns in the face of anthropogenic-induced climate change across environmental and latitudinal gradients.

Extreme heatwave drives topography‐dependent patterns of mortality in a bed‐forming intertidal barnacle, with implications for associated community structure

“…Barnacle beds on substrata that are shaded or receive only oblique solar irradiance will likely be able to persist through future heatwaves and continue to facilitate a diverse community, while populations on shores where irradiance is high will be increasingly impacted, along with the species they facilitate. S. cariosus that survived the heat dome were clearly able to acclimate to extreme temperatures through physiological means (e.g., Muir et al, 2016), but the energetic costs associated with this acclimation may have had sublethal effects on fitness (e.g., reduced fecundity; Curd et al, 2021) not measured here. The ability of S. cariosus to adapt to increased thermal stress is unknown, but given that aquatic invertebrates at mid-latitudes generally demonstrate acclimation capacity to warm conditions (Morley et al, 2019) and that the generation time of barnacles is relatively short, limited adaptation may be possible.…”

Connectivity modelling informs metapopulation structure and conservation priorities for a reef‐building species

“…S. alveolata has a biphasic life cycle with sessile adults, and a planktonic dispersive larval phase (Dubois et al, 2007;Wilson, 1970). While spawning can occur throughout the year, two main peaks are typically observed; in late spring (around May) and late summer (around September) (Curd et al, 2021;Dubois et al, 2007). This species can be locally common but may undergo localized extirpation following natural and anthropogenic perturbations (Dubois et al, 2002(Dubois et al, , 2006Firth et al, 2015Firth et al, , 2021bPlicanti et al, 2016) Despite the importance of conservation and protection afforded to S. alveolata by European legislation, the reefs are classed as datadeficient habitats in many regions (e.g., Bertocci et al, 2017;Firth et al, 2021a), and the number of recorded observations of this species remains limited (Curd et al, 2020).…”

“…S. alveolata has a biphasic life cycle with sessile adults, and a planktonic dispersive larval phase (Dubois et al, 2007; Wilson, 1970). While spawning can occur throughout the year, two main peaks are typically observed; in late spring (around May) and late summer (around September) (Curd et al, 2021; Dubois et al, 2007). This species can be locally common but may undergo localized extirpation following natural and anthropogenic perturbations (Dubois et al, 2002, 2006; Firth et al, 2015, 2021b; Plicanti et al, 2016).…”

“…Furthermore, these are characterized by the highest genetic diversity among Atlantic S. alveolata reefs-another indication of large populations(Nunes et al, 2021), and are likely to contribute to wider metapopulation persistence acting as an important source of larvae to other reefs. Habitat suitability for S. alveolata is, however, predicted to significantly decline under future climate change scenarios(Curd et al, 2021), thus conservation efforts will be of critical importance to minimize local stressors and consolidate the resilience of these key connectivity hubs against anthropogenic-and climatedriven changes.Stepping-stone reefs are, on the other hand, key for connecting distant populations otherwise disconnected, and represent disproportionately important linking pathways among discrete network components(Boulanger et al, 2020). For instance, network analysis identified the Bay of Douarnenez population at the most north-western tip of the French Atlantic coast as pivotal in connecting Atlantic and Channel populations and maintaining S. alveolata metapopulation coherence across the French western coast.…”

“…, these reefs are characterized by the highest genetic diversity among Atlantic S. alveolata reefs-another indication of large populations(Nunes et al, 2021), and are likely to contribute to wider metapopulation persistence acting as an important source of larvae to other reefs. Habitat suitability for S. alveolata is, however, predicted to significantly decline under future climate change scenarios(Curd et al, 2021), thus conservation efforts will be of critical importance to minimize local stressors and consolidate the resilience of these key connectivity hubs against anthropogenic-and climatedriven changes.…”