Habitat-forming species sustain biodiversity and ecosystem functioning in harsh environments through the amelioration of physical stress. Nonetheless, their role in shaping patterns of species ...distribution under future climate scenarios is generally overlooked. Focusing on coastal systems, we assess how habitat-forming species can influence the ability of stress-sensitive species to exhibit plastic responses, adapt to novel environmental conditions, or track suitable climates. Here, we argue that habitat-former populations could be managed as a nature-based solution against climate-driven loss of biodiversity. Drawing from different ecological and biological disciplines, we identify a series of actions to sustain the resilience of marine habitat-forming species to climate change, as well as their effectiveness and reliability in rescuing stress-sensitive species from increasingly adverse environmental conditions.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Globally, rising seawater temperatures contribute to the regression of marine macroalgal forests. Along the Istrian coastline (northern Adriatic), an isolated population of Gongolaria barbata ...persists in a coastal lagoon, representing one of the last marine macroalgal forests in the region. Our objective was to examine the impact of extreme temperatures on morphology and physiology of G. barbata, and test its potential for recovery after simulating marine heatwave (MHW) conditions.
We explored the occurrence of marine heatwaves in southern Istria, adjacent to the study area, as well as extreme temperatures inside the area itself. Subsequently, we performed a thermotolerance experiment, consisting of a stress and recovery phase where we exposed G. barbata thalli to four extreme (28 °C, 30 °C, 32 °C, 34 °C) and one favourable (18 °C) temperature. We then monitored morphological and physiological responses.
Our findings indicate a significant rise in frequency, duration, and intensity of MHWs over decades on the southern Istrian coast. Experimental results show that G. barbata demonstrates both morphological and physiological recovery potential after exposure to temperatures as high as 32 °C. However, exposure to 34 °C led to thallus decay, with limited regeneration ability.
Our results show that G. barbata has a remarkable resilience to long term exposure to extreme temperatures up to 32 °C and suggests that short term exposure to temperatures beyond this, as currently recorded inside the lagoon, do not notably affect the physiology or morphology of local G. barbata. With more MHWs expected in the future, such an adapted population may represent an important donor suitable for future restoration activities along the Istrian coast. These results emphasize the resilience of this unique population, but also warns of the vulnerability of marine macroalgal forests to rising seawater temperatures under rapidly changing climate conditions.
An exploration of historical data suggested that eutrophication patterns might drive long-term fluctuations in Cystoseira populations along the west Istrian Coast (northern Adriatic Sea, Croatia). ...The regimes of northern Italian rivers, which flow approximately 100km west of the study area, mainly modulate the eutrophication levels of the northern Adriatic Sea. A regression of Cystoseira populations from the 1970s through the 1990s corresponded to increased levels of eutrophication in the study area. During the late 1990s, the density of sea urchins, which are efficacious macroalgal predators, decreased, likely due to an intense formation of pelagic mucilage aggregates that resulted in mass mortality episodes of macrozoobenthic species. During the 2000–2013 period, an oligotrophication of the northern Adriatic formed the basis for the recovery of Cystoseira taxa, whose abundances from 2009 to 2013 were similar to those characterising the most flourishing Mediterranean Cystoseira assemblages.
•Northern Italian rivers are the main source of nutrients for the northern Adriatic Sea.•Along the west Istrian Coast, Cystoseira regressed from the 1970s to the late 1990s.•Surveys performed during 2009–2013 revealed a substantial recovery of Cystoseira taxa.•Long-term changes in Cystoseira reflected variations in pelagic eutrophication levels.•The pelagic mucilage phenomenon could modify the structure of benthic assemblages.
Artificial structures are sprawling in marine seascapes as a result of burgeoning coastal populations, increasing development and energy demand, and greater risks from climate change, storm surges ...and sea level rise. Interest in designing marine developments that maintain vital ecosystems and critical services is growing, but progress requires understanding the factors that influence the ecological performance of these novel artificial habitats. We combined field observations and experiments along 500 km of the North Adriatic coastline to analyse the performance of artificial substrata as habitats to support canopy‐forming algae belonging to the genus Cystoseira, among the most ecologically relevant foundation species along rocky Mediterranean coastlines. We aimed to: clarify the underlying factors controlling the growth of Cystoseira in the artificial habitat; contrast the relative importance of these factors between artificial and natural habitats; and test the generality of the results across different sites and species of Cystoseira. We found that: (i) the growth of canopy algae was significantly lower on artificial structures compared to rocky reefs; (ii) such lower growth of canopy algae was not related to less favourable abiotic conditions but to higher biotic disturbance from both consumptive and nonconsumptive interactions on the artificial structures compared to the natural reef; and iii) this was consistent across different study sites and canopy‐forming species. We conclude that biological factors influencing the growth of canopy algae, such as herbivory or other nonconsumptive disturbances, can differ substantially between artificial and natural habitats. The unusually large and previously unreported biotic pressure characterizing many artificial structures can negatively affect their performance as habitats to support ecologically relevant, foundation species. Synthesis and applications. While nearly all considerations to improve the ecological performance of hard marine infrastructures focus on abiotic factors (e.g. construction materials, surface texture, habitat complexity or water quality), careful consideration of critical biotic factors is also needed to further progress the green engineering of sprawling marine infrastructures.
The knowledge on the hard bottom polychaete assemblages in the Northern Adriatic Sea, a Mediterranean region strongly affected by environmental pressures, is scarce and outdated. The objective of ...this paper was to update the information on polychaete diversity and depict their patterns of natural spatial variation, in relation to changes in algal coverage at increasing depth. Hard bottom benthos was quantitatively sampled by scraping off the substrate from three stations at Sveti Ivan Island (North Adriatic) at three depths (1.5 m, 5 m and 25 m). Polychaete fauna comprised 107 taxa (the majority of them identified at species level) belonging to 22 families, with the family Syllidae ranking first in terms of number of species, followed by Sabellidae, Nereididae, Eunicidae and Serpulidae. Considering the number of polychaete species and their identity, the present data differed considerably from previous studies carried out in the area. Two alien species, Lepidonotus tenuisetosus, which represented a new record for the Adriatic Sea, and Nereis persica, were recorded. The highest mean abundance, species diversity and internal structural similarity of polychaete assemblages were found at 5 m depth, characterised by complex and heterogeneous algal habitat. The DISTLM forward analysis revealed that the distribution of several algal taxa as well as some algal functional-morphological groups significantly explained the observed distribution patterns of abundance and diversity of polychaete assemblages. The diversity of the North Adriatic hard bottom polychaete fauna is largely underestimated and needs regular updating in order to detect and monitor changes of benthic communities in the area.
The
forest inhabiting Šćuza lagoon on the southern Istrian coast (northern Adriatic) represents the last significant refuge for this species among the shallow waters of the Istrian Coast. The lagoon ...is characterised by extreme winter and summer temperatures. Moreover, the absence of certain grazers could be one of the main factors favouring the development and growth of
forest. Two morphologically distinct forms of
inhabit the lagoon: attached and detached. Abundance and morphological characteristics of each form were analysed in randomly sampled thalli. The wet weight, thallus length, number of cauloids and total cauloid length were significantly higher in the detached than in the attached form. Although the main cauloid was highly branched in both forms, its total length was up to three times higher in the detached than in the attached form. Our study suggests that this population of
can thrive in the extreme conditions found in the lagoon, while also exhibiting two distinct forms. Furthermore, this large population could serve as a donor for future restoration attempts on the western Istrian Coast where a decline of
has been confirmed in recent years.
A very common intertidal alga, Corallina officinalis, serves as a refuge for numerous invertebrates within its settlements. The composition and structure of invertebrates may differ in relation to ...different natural or human-induced stress, and this study examined the effects of anthropogenic impact on the abundance and diversity of mollusks residing within C. officinalis settlements. Sampling was conducted during two seasons (Season 1 = algae’s maximum vegetation growth and Season 2 = algae’s minimum vegetation growth). Gastropods and bivalves made up 50% of all invertebrates identified, with a total of 47 species of gastropods, 25 species of bivalves, and one polyplacophoran species recorded. Considering the overall count of individuals, 4562 gastropods, 21,738 bivalves, and 260 polyplacophorans were collected from all available Corallina samples. The results indicated that locations under human impact showed a reduced number of the most abundant gastropod and bivalve species and a reduced average number of individuals.
Available research on invertebrates in Corallina officinalis settlements shows a high level of biodiversity due to a complex habitat structure. Our aim was to examine seasonal changes in the ...invertebrate population, considering the algae’s growth patterns. Nine locations with over 90% algal coverage were selected in southern Istria, where quantitative sampling was performed using six replicates of 5 × 5 cm quadrats in each location. Results showed that 29,711 invertebrates were found during winter (maximum algae growth) and 22,292 during summer (minimum algae growth), with an extrapolated average density of 220,000 and 165,200 individuals per square meter, respectively. The total number of individuals showed a linear increase as the algae biomass increased. The highest density, 586,000 individuals, was recorded in the Premantura area during winter. Dominant groups such as amphipods, polychaetes, bivalves and gastropods made up over 80% of the invertebrates. Our study confirms high invertebrate richness in the C. officinalis settlements, with the maximum density being the highest when compared to previously published data.
Algal‐associated bacteria are fundamental to the ecological success of marine green macroalgae such as Caulerpa. The resistance and resilience of algal‐associated microbiota to environmental stress ...can promote algal health and genetic adaptation to changing environments. The composition of bacterial communities has been shown to be unique to algal morphological niches. Therefore, the level of response to various environmental perturbations may in fact be different for each niche‐specific community. Factorial in situ experiments were set up to investigate the effect of nutrient enrichment and temperature stress on the bacterial communities associated with Caulerpa cylindracea. Bacteria were characterized using the 16S rRNA gene, and the community compositions were compared between different parts of the algal thallus (endo‐, epi‐, and rhizomicrobiome). Resistance and resilience were calculated to further understand the changes of microbial composition in response to perturbations. The results of this study provide evidence that nutrient enrichment has a significant influence on the taxonomic and functional structure of the epimicrobiota, with a low community resistance index observed for both. Temperature and nutrient stress had a significant effect on the rhizomicrobiota taxonomic composition, exhibiting the lowest overall resistance to change. The functional performance of the rhizomicrobiota had low resilience to the combination of stressors, indicating potential additive effects. Interestingly, the endomicrobiota had the highest overall resistance, yet the lowest overall resilience to environmental stress. This further contributes to our understanding of algal microbiome dynamics in response to environmental changes.
The resistance and resilience of algal‐associated microbiota to environmental stress can promote algal health and genetic adaptation to changing environments. Bacteria associated with separate morphological niches along the thallus of Caulerpa cylindracea differed significantly in response to environmental perturbations, further contributing to our understanding of algal microbiome dynamics.
During the spring of 2016, benthic blooms of
(Ectocarpales, Phaeophyceae) producing voluminous mucilaginous aggregates frequently occurred at surveyed locations of the west Istrian Coast (northern ...Adriatic Sea, Croatia). In mucilage-affected macroalgal assemblages, the concentration of ammonium ranged from 50 to 300 μM. To investigate whether ammonium has the potential to harm fucalean species, a selected taxon,
was exposed to increased ammonium concentrations in laboratory conditions. Experiments revealed that exposure to 50 μM ammonium severely damaged the thalli while exposure to 300 μM caused complete necrosis of thalli in 2 days. These findings suggest that benthic algal blooms, enhanced by climate change and eutrophication, can negatively affect the populations of fucalean species due to production of ammonium during the decay of mucilaginous aggregates, causing thallus necrosis.
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