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1. Along urbanised coastlines, urban infrastructure is increasingly becoming the dominant habitat. These structures are often poor surrogates for natural habitats, and a diversity of eco-engineering approaches have been trialled to enhance their biodiversity, with varying success. 2. We undertook a quantitative meta-analysis and qualitative review of 109 studies to compare the efficacy of common eco-engineering approaches (e.g. increasing texture, crevices, pits, holes, elevations and habitat-forming taxa) in enhancing the biodiversity of key functional groups of organisms, across a variety of habitat settings and spatial scales. 3. All interventions, with one exception, increased the abundance or number of species of one or more of the functional groups considered. Nevertheless, the magnitude of effect varied markedly among groups and habitat settings. In the intertidal, interventions that provided moisture and shade had the greatest effect on the richness of sessile and mobile organisms, while water-retaining features had the greatest effect on the richness of fish. In contrast, in the subtidal, small-scale depressions which provide refuge to new recruits from predators and other environmental Stressors such as waves, had higher abundances of sessile organisms while elevated structures had higher numbers and abundances of fish. The taxa that responded most positively to eco-engineering in the intertidal were those whose body size most closely matched the dimensions of the resulting intervention. 4. Synthesis and applications. The efficacy of eco-engineering interventions varies among habitat settings and functional groups. This indicates the importance of developing site-specific approaches that match the target taxa and dominant stressors. Furthermore, because different types of intervention are effective at enhancing different groups of organisms, ideally a range of approaches should be applied simultaneously to maximise niche diversity.

As coastal cities around the world expand, and sea levels and the frequency of storms rise, natural shorelines are steadily being replaced by artificial defences such as seawalls. A growing number of studies have documented the assemblages that inhabit these novel environments, and some have contrasted them against those found in their natural analogues: rocky shores. Most of this work has, however, been conducted in temperate regions, and there is limited research on seawalls in the tropics. To address this, we conducted monthly surveys of adjacent seawall and rocky shores at multiple sites around Singapore for 1 yr. Our results concur with previous temperate studies—artificial seawalls support a lower diversity but share a substantial number of species with rocky shores. Multivariate analyses reveal that assemblage differences were largely driven by species that were found in both habitats (e.g. detritivore Ligia exotica, grazer Monodonta labio and carnivorous whelk Drupella margariticola) but occurred in different abundances. We also conducted (for the first time on seawalls) stable isotope analyses to elucidate the diets of the common species found in both habitats. Turf algae, which were found to be present in significantly lower abundances on seawalls, could possibly contribute substantially to the diets of many dominant herbivores. Future seawall enhancement efforts in the tropics could therefore look into whether enhancing turf algae will improve biodiversity.

Urban areas have broad ecological footprints with complex impacts on natural systems. In coastal areas, growing populations are advancing their urban footprint into the ocean through the construction of seawalls and other built infrastructure. While we have some understanding of how urbanisation might drive functional change in terrestrial ecosystems, coastal systems have been largely overlooked. This study is one of the first to directly assess how changes in diversity relate to changes in ecosystem properties and functions (e.g. productivity, filtration rates) of artificial and natural habitats in one of the largest urbanised estuaries in the world, Sydney Harbour. We complemented our surveys with an extensive literature search. We found large and important differences in the community structure and function between artificial and natural coastal habitats. However, differences in diversity and abundance of organisms do not necessarily match observed functional changes. The abundance and composition of important functional groups differed among habitats with rocky shores having 40% and 70% more grazers than seawalls or pilings, respectively. In contrast, scavengers were approximately 8 times more abundant on seawalls than on pilings or rocky shores and algae were more diverse on natural rocky shores and seawalls than on pilings. Our results confirm previous findings in the literature. Oysters were more abundant on pilings than on rocky shores, but were also smaller. Interestingly, these differences in oyster populations did not affect in situ filtration rates between habitats. Seawalls were the most invaded habitats while pilings supported greater secondary productivity than other habitats. This study highlights the complexity of the diversity-function relationship and responses to ocean sprawl in coastal systems. Importantly, we showed that functional properties should be considered independently from structural change if we are to design and manage artificial habitats in ways to maximise the services provided by urban coastal systems and minimise their ecological impacts.

The urbanisation of coastal areas increases both Artificial Light At Night (ALAN) and man-made structures. ALAN poses significant challenges to coastal ecosystems by altering species physiology and behaviour. Its effects might differ considerably between man-made and natural habitats due to varying habitat complexity and biological assemblages. This systematic review assesses the current knowledge and gaps regarding the ecological effects of the interaction between ALAN and different coastal hard-bottom habitats on intertidal and shallow-subtidal reefs. Of the 57 retrieved studies, most are laboratory experiments (40) on the physiology and behaviour of rocky shore (24) or coral reef (16) species. Field studies were conducted in artificial (6) and natural habitats (9), with only 2 comparing the two habitat types. These studies illustrate ALAN impacts on various species, with potential cascading effects on entire communities through the alteration of competitive and consumer-resource interactions. Different habitat structures may interact with ALAN by generating highly heterogeneous lightscapes (e.g., natural rocky shores), regular light-shadow mosaics (e.g., breakwaters), vast homogeneously lit areas (e.g., seawalls), or constantly shaded areas (e.g., pontoons). This creates a variable mismatch in natural light conditions, which may be further influenced by the introduction of additional light sources (e.g., moored boats with underwater coloured lights). As coastal development and light pollution continue to grow, research should prioritise understanding their interactive effects in shaping species relationships and ecosystem dynamics. Although the available evidence suggests that ALAN effects may vary between natural and man-made habitats, further research is needed to draw any general conclusion.

Owing to the synergistic combination of a hybrid organic–inorganic nature and a chemically active porous structure, metal–organic frameworks have emerged as a new class of crystalline materials. The current trend in the chemical industry is to utilize such crystals as flexible hosting elements for applications as diverse as gas and energy storage, filtration, catalysis, and sensing. From the physical point of view, metal–organic frameworks are considered molecular crystals with hierarchical structures providing the structure‐related physical properties crucial for future applications of energy transfer, data processing and storage, high‐energy physics, and light manipulation. Here, the perspectives of metal–organic frameworks as a new family of functional materials in modern physics are discussed: from porous metals and superconductors, topological insulators, and classical and quantum memory elements, to optical superstructures, materials for particle physics, and even molecular scale mechanical metamaterials. Based on complementary properties of crystallinity, softness, organic–inorganic nature, and complex hierarchy, a description of how such artificial materials have extended their impact on applied physics to become the mainstream in material science is offered. Metal–organic frameworks extend their impact on modern physics and become the mainstream in material science because of complementary properties as crystallinity, softness, organic–inorganic nature, and complex hierarchy.

Aim Biological invasions and changes in land and sea use are among the five major causes of global biodiversity decline. Shipping and ocean sprawl (multiplication of artificial structures at the expense of natural habitats) are considered as the major forces responsible for marine invasions and biotic homogenization. And yet, there is little evidence of their interplay at multiple spatial scales. Here, we aimed to examine this interaction and the extent to which the type of artificial habitat alters the distribution of native and non‐indigenous biodiversity. Location Southeast Pacific—Central Chilean coastline. Methods Settlement plates were deployed upon two types of artificial habitats (floating and non‐floating hard substrates) at a total of ten study sites, exposed to either international or local traffic. After colonization periods of 3 and 13 months, plates were retrieved to determine their associated fouling sessile assemblages at an early and late stage of development, respectively. Putative confounding factors (temperature, metal concentrations) were taken into account. Results While traffic type had no detectable effect, there were strong differences in community structure between habitats, consistent across the study region. These differences were driven by non‐indigenous species which contributed to 58% and 40% of the community structure in floating habitats after 3 and 13 months, respectively—roughly 10 times greater than in their non‐floating counterparts. Assemblages on floating structures also displayed a lower decline in similarity with increasing distance between sampling units, being thus more homogenous than non‐floating habitats at the regional scale. Main conclusions With the absence of international traffic effect, the colonization success by non‐indigenous species appears to be mainly habitat‐dependent and driven by local propagules. Floating structures not only provide specific niches but characteristics shared with major introduction and dispersal vectors (notably hulls), and in turn constitute important corridors to invasions and drivers of biotic homogenization at multiple scales.

Non-indigenous species (NIS) establish and thrive on floating artificial substrata along mid-latitude shores, which might serve as propagule reservoirs and stepping stones for their dispersal. However, often, the NIS are not able to colonize the adjacent seafloor, where high predation pressure by benthic predators might inhibit them. To test this hypothesis, we quantified and compared consumption rates of standardized bait (squidpops) in four water depth zones (sea surface, sub-surface, midwaters, seafloor) in five representative regions in the Southeast Pacific, covering oceanic Rapa Nui (Easter Island; 27°S, 109°W; November 2022) as well as the Chilean continental coast (29–41°S, 71–73°W; March–June 2022). We found a strong overall effect of water zonation, with significant bait consumption being limited to the seafloor and occurring only sporadically in other depth zones. Consumption frequencies also differed between experimental regions but were not influenced by latitude or mean sea surface temperature. An analogous experiment with the NIS Ciona robusta , conducted at one sampling site, showed that the occurrence or absence of predation per site and water depth zone, but not the exact consumption rates, concurred between both bait types. Our results confirm that predation in SE Pacific temperate shallow waters mainly depends on benthic predators that cannot reach higher zones of the water column. These findings have far-reaching implications, as they indicate that predation rates in mid-latitude systems might be underestimated through commonly used water column-based experiments. For a comprehensive estimation of predation pressure in a given system, future studies should consider differences between vertical water zones.

AimTrait-based approaches are powerful to examine the processes associated with biological invasions. Functional comparison among native and non-indigenous species (NIS) can notably infer whether novel assemblages result from neutral or niche-based assembly rules. Applying such a framework to biofouling communities, our study aimed to elucidate their distributions within two marine urban habitats (namely floating vs. nonfloating habitats).LocationSoutheast Pacific—Central Chilean coastline.MethodsHere, we examined the distribution of 12 functional traits in fouling communities established on settlement plates, after 3 and 13 months of deployment in the two habitats and across ports in Central Chile. Based upon previously described differences of assemblages and NIS contribution across habitats, we hypothesized that nonindigenous, cryptogenic and native taxon pools would be functionally distinct (and trait biased), and that functional diversity and structure would vary across habitats and successional stages.ResultsOur results show, as anticipated, that nonindigenous (13 taxa), cryptogenic (12) and native (18) taxon pools are functionally distinct, though overlapping in the trait space. Non-indigenous species are rather related to colonizing traits, while native species are more related to competitive traits. Only one widespread NIS was functionally similar to the late successional and most competitive native species, including taxa elsewhere invasives. Despite differences in taxonomic composition between habitats, we did not observe functional differences between them. In contrast, temporal variations across colonization stages were detected along with an increased contribution in large and long-lived taxa, together with site-specific trajectories.Main ConclusionsWe conclude that the functional distinctness among nonindigenous, cryptogenic and native taxa occupying artificial habitats in ports reflects niche-based processes. Site-specific trajectories indicate that scale-dependent assembly processes, such as dispersal and species interactions, are at play.

Obstacle avoidance based on a monocular camera is a challenging task due to the lack of 3D information for Unmanned Aerial Vehicle. Recent methods based on Convolutional Neural Networks for monocular depth estimation and obstacle detection become widely used. However, collision avoidance with depth estimation usually suffers from long computational time and low avoidance success rate. A new collision avoidance system is proposed which uses monocular camera and intelligent algorithm to avoid obstacles on real time processing. Several experiments have been conducted on crowded environments with several object types. The results show outstanding performance in terms of obstacles avoidance and system response time compared to contemporary approaches. This makes the proposed approach of high potential to be integrated in crowded environments. This study proposes a new collision avoidance system using monocular camera and intelligent algorithm to avoid obstacles on real time processing. Experimental results using Telo drone conducted in crowded environments with several object types show outstanding performance in terms of obstacles avoidance and system response time compared to contemporary approaches. This makes the proposed system of high potential to be integrated in crowded environments.

Radially self-accelerating acoustic beams (RSABs) with rotating field distributions enable three-dimensional manipulation of particles. Nevertheless, the generation of desired RSABs is always a challenge. In this study, we derive a general form for the RSABs with a rotating acoustic field. We investigate the correlation between acoustic intensity and phase distribution of the RSAB in-depth via theoretical calculations. Artificial structure plates carved with Archimedean spiral slits are designed to produce two-component RSABs (TRSABs). It is found that the number of main lobes, rotational speed, and initial position of the TRSAB can be modulated by simply changing the number of arms, initial radius, and relative angle of the two sets of spirals. The experimental and numerical demonstrations confirm the ability of artificial structure plates to generate TRSABs. Finally, simulations are performed to calculate the acoustic radiation force on Rayleigh polydimethylsiloxane particles in a TRSAB. The work presented here could greatly benefit acoustic particle three-dimensional trapping and manipulation.