Unmanned Aerial Systems (UASs) for Environmental Monitoring: A Review with Applications in Coastal Habitats

Nowadays the proliferation of small unmanned aerial systems or vehicles (UAS/Vs), formerly known as drones, coupled with an increasing interest in tools for environmental monitoring, have led to an exponential use of these unmanned aerial platforms for many applications in the most diverse fields of science. In particular, ecologists require data collected at appropriate spatial and temporal resolutions to describe ecological processes. For these reasons, we are witnessing the proliferation of UAV-based remote sensing techniques because they provide new perspectives on ecological phenomena that would otherwise be difficult to study. Therefore, we propose a brief review regarding the emerging applications of low-cost aerial platforms in the field of environmental sciences such as assessment of vegetation dynamics and forests biodiversity, wildlife research and management, map changes in freshwater marshes, river habitat mapping, and conservation and monitoring programs. In addition, we describe two applications of habitat mapping from UAS-based imagery, along the Central Mediterranean coasts, as study cases: (1) The upper limit of a Posidonia oceanica meadow was mapped to detect impacted areas, (2) high-resolution orthomosaic was used for supporting underwater visual census data in order to visualize juvenile fish densities and microhabitat use in four shallow coastal nurseries

Current observations from a looking down vertical V-ADCP: interaction with winds and tide? The case of Giglio Island (Tyrrhenian Sea, Italy)

Summary In the context of the environmental monitoring of the Concordia wreck removal project, measurements of currents, winds and sea level height were made along the eastern coast of the Giglio Island, Tyrrhenian Sea (Italy), during 2012–2013. The aim of the study was to investigate the effect of atmospheric forcing and periodic sea-level changes on the coastal currents. Normalised Cross-Correlation Function analysis allowed us to correlate these observations. A marked inter-seasonal variability was found in both current and local wind velocity observations but a significant level of correlation between the data was only found during strong wind events. Current and wind directions appeared to be uncorrelated and current measurements showed a predominant NW–SE direction, presumably linked to the shape and orientation of Giglio Island itself. During strong winds from the SSE, current flow was towards the NNW but it suddenly switched from the NNW to the SE at the end of wind events. The results show that, at Giglio Island, currents are principally dominated by the general cyclonic Tyrrhenian circulation, and, secondly, by strong wind events. The sea level had no effects on the current regime

<strong>The polychaete community of the Fregene artificial reef (Tyrrhenian Sea, Italy): a 20-year study (1981–2001)</strong>

The artificial reef of Fregene, Italy, was built in 1981 as a multipurpose structure with the intent of protecting the coastal environment from illegal trawling and also improving fishery production. It is located at 10–14 m depth on a sandy-silty seabed in the Tyrrhenian Sea, 5 nmi north of the outlet of the Tevere River (Latium, Italy) and 1.5 nmi offshore the town of Fregene (Latium, Italy). The development of the polychaete community on the reef was studied from May 1981 to December 2001 in order to examine long-term community dynamics and verify to what extent changes in polychaete assemblage could depict the development of the benthic assemblage. At each sampling time, two standard surfaces of 400 cm2 were scraped from the vertical walls of the same block. Temporal changes in the development of the polychaete community were detected by univariate (S, N, ExpH', 1/Simpson, J') and multivariate (CLUSTER, nMDS) analysis of the faunal data. Functional structure of the community was also analyzed. Changes in the community structure were shown by an overall increasing trend in the total number of species and individuals. The 20-year development of the polychaete community was divided into five different phases representing different benthic assemblages on the reef: the first two periods correspond to settlement of pioneer species (1981–82); the third is a phase characterized by Mytilus galloprovincialis dominance and regression (1983–85); the fourth is a phase of mud accumulation between dead balanids, with the presence of laminar bryozoans (1991–92), and the last corresponds to a phase dominated by bryozoan bioconstruction (2001). The increased complexity in the benthic assemblage and substratum on the reef is also shown by an increased differentiation and distribution of polychaete functional groups. Increasing environmental heterogeneity on the reef is the basic factor that affected biodiversity by generating new niches that could be occupied by additional species with different ecology. The similarity of the benthic assemblage observed on the reef in 2001 with natural bioconstructions suggest that after two decades the ecological succession has lead to a settlement at a steady-state of equilibrium with the surrounding environment

Analysis of demersal assemblages off the Tuscany and Latium coasts (north-western Mediterranean

SUMMARY: A four-year time series (1994-1997) of groundfish trawl surveys performed within the European Union Project “MEDITS ” (Mediterranean International Trawl Surveys), was analysed to identify and describe the fish assemblages along the continental shelf and slope of Tuscany and Latium (Italy), in the north-western Mediterranean. Cluster analysis was used to group samples with similar species composition in terms of abundance, biomass and frequency of occurrence. Results allowed the identification of four to five broad assemblages along the depth gradient: a strictly coastal group (&lt; 50 m depth), two groups in the upper and lower part of the continental shelf (essentially 50-200 m), an epibathyal group (200-450 m) and a group derived from hauls made at depths greater than 450 m. Each assemblage corresponded to a faunistic association with relatively homogeneous and persistent species composition, biomass and density indices. Key words: assemblages, cluster analysis, demersal resources, western Mediterranea

Unusual algal turfs associated with the rhodophyta Phyllophora crispa: Benthic assemblages along a depth gradient in the Central Mediterranean Sea

Macroalgal assemblages dominated by the turf-forming alga Phyllophora crispa are described in detail for the first time in the Central Mediterranean Sea. This particular form of algal growth, which comprises an upper mixed layer of multiple algal species with a basal stratum formed by entangled thalli of P. crispa, was observed for the first time in 2012 along the promontory of Punta del Lazzaretto (Giglio Island, Italy). In this study, this assemblage was analysed to document the diversity of macroalgae and invertebrate associated communities and assess their distribution along a depth gradient. The algae forming turfs grow directly on the rock at low depth up to 10–15 m depth, while they grow above P. crispa from 15 m to 35 m depth, resulting in luxuriant beds covering up to 100% of the substrate. Multivariate analysis revealed clear differences regarding algae and invertebrate species richness and abundance between shallow and deep strata because of the dominance of Phyllophora crispa at depths greater than 20 m. The long laminal thalli of P. crispa favoured sessile fauna colonization, while the vagile species were principally linked to the architectural complexity of the turf layer created by the P. crispa, which increased the microhabitat diversity and favoured sediment deposition within the turf layer. The complex structures of these turf assemblages and their widespread distribution along the whole coast of the island suggest a well-established condition of the communities linked to the high natural sedimentation rate observed in the area

Changes at very short time scale: An example from the marine benthic communities

XIV Congresso dell'Associazione Italiana di Oceanologia e Limnologia (AIOL), Garda (VR), 25-28 settembre 2000.-- 7 pages, 2 figures, 2 tablesThe present paper reports data obtained from a study carried out in October and November 1998 in a marine area off S. Vincenzo (LI) along the Tuscany coast (South Ligurian Sea, Italy) between 29 and 36 meters depth. The benthic community corresponds to the Biocénose de la Vase Terrigène Côtière (VTC) confirming previous authors who described the VTC biocoenoses as the dominant assemblage in this area. According to nMDS this community showed a well defined temporal gradient which appeared quite clear if a monthly interval is taken into account. Such an interval resulted long enough to record modifications in composition and structure of the benthic community as well as in the textural characteristic of the sediments which showed, in the last sampling date, an increase of the clayed component with a parallel decrease of siltPeer reviewe