Using a UAV-Mounted Multispectral Camera for the Monitoring of Marine Macrophytes

Marine macrophytes constitute one of the most productive ecosystems on the planet, as well as one of the most threatened by anthropogenic activities and climate change. Their monitoring is therefore essential, which has experienced a fast methodological evolution in recent years, from traditional in situ sampling to the use of satellite remote sensing, and subsequently by sensors mounted on unmanned aerial vehicles (UAV). This study aims to advance the monitoring of these ecosystems through the use of a UAV equipped with a 10-band multispectral camera, using different algorithms [i.e., maximum likelihood classifier (MLC), minimum distance classifier (MDC), and spectral angle classifier (SAC)], and using the Bay of Cádiz Natural Park (southern Spain) as a case of study. The results obtained with MLC confirm the suitability of this technique for detecting and differentiating seagrass meadows in a range of 0–2 m depth and the efficiency of this tool for studying and monitoring marine macrophytes in coastal areas. We inferred the existence of a cover of 25452 m2 of Cymodocea nodosa, and macroalgae species such as Caulerpa prolifera, covering 22172 m2 of Santibañez (inner Bay of Cádiz).

UAS Identify and Monitor Unusual Small-Scale Rhythmic Features in the Bay of Cádiz (Spain)

Unusual shore-normal and barred-like rhythmic features were found in Camposoto Beach (Bay of Cádiz, SW Spain) during a monitoring program using unmanned aerial systems (UAS). They appeared in the backshore and persisted for 6 months (October 2017–March 2018). Their characteristics and possible formation mechanism were investigated analyzing: (1) UAS-derived high-resolution digital elevation models (DEMs), (2) hydrodynamic conditions, and (3) sediment samples. The results revealed that the features did not migrate spatially, that their wavelength was well predicted by the edge wave theory, and that they shared characteristics with both small-scale low-energy finger bars (e.g., geometry/appearance and amplitude) and swash cusps (e.g., wavelength, seaward circulation pattern, and finer and better sorted material in the runnels with respect to the crests). Our findings pinpoint to highly organized swash able to reach the backshore during spring tides under low-energy and accretionary conditions as well as backwash enhanced by conditions of water-saturated sediment. This study demonstrates that rhythmic features can appear under different modalities and beach locations than the ones observed up to date, and that their unusual nature may be attributed to the low spatiotemporal resolution of the traditional coastal surveying methods in comparison with novel technologies such as UAS.

La red de búnkeres construida en el siglo XX entre la bahía de Cádiz y la desembocadura del Guadalquivir

The bunker network built in the twentieth century between the Bay of Cádiz and the mouth of the Guadalquivir RiverThe Andalusian Defensive Architecture Plan (PADA) justifies the legal protection of all Andalusian defensive architecture based on the historical condition of the region as a border of kingdoms and civilizations. It supports by using the Decree of April 22, 1949 on the protection of Spanish castles; to the subsequent Law 16/1985 on Spanish Historical Heritage, which declared Bien de Interés Cultural the assets included in the Decree of 1949; and extending the term “castle” to the more generic of “defensive architecture” or “military architecture”. However, the fortification of the twentieth century in Andalusia hardly has any protection. Devices such as the north shore of the Strait or the Bay of Cádiz remain unnoticed and abandoned to their fate. The objective of this contribution is to present this device: the defensive network of bunkers for machine guns and / or anti-tank guns executed in the surroundings of the Bay of Cádiz and the mouth of the Guadalquivir River (from Chiclana de la Frontera to Almonte, passing through Cádiz, Rota or Sanlúcar de Barrameda, among others). Due to the territorial condition of the system, georeferencing and parametrization tools will be applied to the original planimetry located in the Southern Military Intermediate Archive of Seville, deepening in what was the setup and tactical sense of the works around 1945.

Territorial impacts of sea-level rise in marsh environments. The case of the Bay of Cádiz, Spain

How can sea-level rise affect territory? Has territorial planning adjusted to this new situation? This paper analyses the possible ramifications of changes in tidal recurrence over the course of this century in a potentially vulnerable marsh environment, such as the Bay of Cádiz, in southern Spain, where sea-level rise is already a fact. For that purpose, the regionalisation criterion is used as a basis for adjusting the magnitude of global problems to subregional scale. Geographic information systems are applied to portray the forecasted territorial changes according to the RCP4.5 and RCP8.5 scenarios presented by the Intergovernmental Panel on Climate Change (IPCC) for the years 2050 and 2100. Projections of sea-level rise show that the tide is travelling farther inland, not just invading unoccupied areas of marshes and beaches but also reaching urban and productive areas. Estimates indicate that the floodable area could expand by more than 20% in 2050, with a further 2,000 ha of flooded areas added in 2100 for either of the two scenarios used. The occurrence of these changes, regardless of the model used, would therefore entail an alteration of the environmental, social, cultural and economic values and elements of the Bay of Cádiz, with the Natural Park being the most affected area. In response to these consequences, the need to apply the resulting projections to other variables is insisted on, with a view to introducing territorial management tailored to this new and already present reality. Application of the regionalisation criterion to study repercussions of the climate crisis in the Bay of Cádiz could serve as a precedent for the development of adaptation strategies in other marsh environments at subregional or local level.

Response of a coastal lagoon sediment budget to extreme events and climate change implications: The case of the Bay of Cadiz

<p>Climate change has resulted in increased storminess and sea-level change that affects the morphodynamics of bays worldwide, impacting both the ecosystem and local infrastructure. This study explores the impact of differing storm winds on the sediment budget of the Bay of Cadiz. The Bay of Cadiz is a highly altered coastal lagoon located in Southwest Spain surrounded by ports, navigation channels, and urban developments and is of high socioeconomic and environmental importance. The human interactions with the bay have already caused morphological impacts, which could be exacerbated by increased storminess. Potential impacts on the sediment budget of the Bay of Cadiz will be modeled using a Delft3D model previously calibrated and tested using field data from December 2011 to January 2012. The model will consider a variety of storm wind scenarios and observe their impacts on sediment transport within the bay, identifying sources and sinks. This will help to estimate the potential impacts of climate change and increased storminess on the bay and the surrounding areas.</p>

Coastal Ecosystem Services Assessment in the Framework of the Climate Change Effects: Study Case Bay of Cadiz Natural Park (Spain)

An ecosystem service assessment in the Bay of Cadiz Natural Park has been undergone in relation to the effects of climate change. The ecosystems in the study area were analyzed and 3 different types were indentified: 1) beaches and dunes, 2) marshes and 3) marine environment (including the marine phanerogam meadows), and the ecosystem services (providing, regulating and cultural services) that these ecosystems offer have also been identified. The services state was valued to determine which ones are the most exposed and which the most vulnerable to the climate change effects and its possible future trends through climatic simulators has been made. The results allowed to conclude that most of the ecosystem services showed a negative trend, especially the regulation services which are more associated with the climate change phenomenon. Keywords: Protected natural area, ecosystem services, evaluation of ecosystems, human well-being, climate change.