Date : 06/06/2019
School name :
Agrupamento Dr.º Laura Ayres - EB 2,3 de Quarteira n.2
Student's age :
Number of team members :
Summary of the project :
Ribeira do Almargem has a seasonal regime suffering great variations of the water level being sometimes reduced to the main channel (less than 2m) and ends in a small coastal lagoon, surrounded by spots of pine, agricultural land and a narrow dune barrier. This lagoon is a National Ecological Reserve used as a feeding and resting area for about 38 species of waterfowl. With the rainwater runoff, the entire surface of the pond is flooded. During summer, the shallower channels dry up, and in the central zone sand banks appear. During most of the year the lagoon is isolated from the sea, however during the period of live tides and storms, it is frequent the overcome of dune barrier and the entrance of salted water. This lagoon is completely dependent on the amount of water that comes to it, either from the sea or from the river that feeds it. In this way, extreme weather phenomena have had drastic effects on this ecosystem. In order to study the impact of these changes, we analysed satellite images (https://www.sentinel-hub.com/explore/eobrowser), weather records, IPCC report, AMAL report (Intermunicipal Community of the Algarve), Assessment of the Algarve's Wetlands and newspapers to make a comparative study on the changes of the lagoon in different times of the year and in different years, of which there were record of extreme meteorological phenomena. Data on vegetation, precipitation and temperature in the last years were analysed. After this analysis it became necessary to make a field trip to the site to collect photos / samples and validate “in situ” these records (a Field Guide was developed to guide the field exploration). The photos and samples collected (water, sands, vegetation) were analysed and worked in the classroom. The work developed always counted with the support of professors from the University of Algarve specialists in Coastal Dynamics and Climate Change, the collaboration of the Parish Council of Quarteira and was developed in interdisciplinarity involving the di-verse students´ discipline.
Main results :
Data showed that in periods of extreme drought there is a significant reduction of the flow and the water temperature increases significantly causing the death of numerous fishes and some waterfowl whose nesting occurs in the lagoon vegetation (several species of waterfowl were identified). During the field exploration, it was observed that the vegetation presents significant differences along the lagoon's: the northern zone presents a higher density of vegeta-tion cover, the east/west margins vegetation typical of marshes while the southern zone finds typical dune vegetation. It was possible to identify several species of aquat-ic birds as well as the urban pressure to which the river and lagoon are submitted. Results point out to an urgent need for conservation. The urban pressure to which the entire area is submittes and the silting up of the water lines that supply the lagoon (observed at field leave) prevent the guarantee of a constant freshwater supply for the maintenance of biodiversity. This inconstancy in the water supply is visible in the vari-ous channels made up of an extensive area of “caniçal” (which is or flooded or almost dry) and the various maps generated by the analysis of satellite images. The meteorological records analyzed, as well as future projections, point to a rise in global mean temperature and a decrease in progressive precipitation. These conju-gated factors caused changes in the volume of water and have a huge impact on the lagoon and its biodiversity. On the other hand, some extreme weather events, such as those of 2015 and 2018, can lead to floods and floods breaking the sandy barrier and allowing partial replacement of the lagoon body. In addition, the data highlight changes in the morphology of the lagoon due to intense and continuous anthropic interference in the north (drainage and landfills) linked to agricultural activities and urban-tourist expansion.
Actions to help lessen the problem :
We can´t do anything to fight the address climate change, but as these changes are caused by man's action, we have decided to focus our actions on awareness of our local community. In order to do this, we initially publicized the project and shared the results of our research as well as suggestions for measures that could mitigate some effects of climate change to local entities and the general community. These actions were deliv-ered in a public session in the Quarteira Autonomous Center. "Conservation of nature, protection of natural spaces and landscape, preservation of species of fauna and flora and their natural habitats, maintenance of ecological balanc-es and protection of natural resources against all forms of degradation objectives of pub-lic interest", in accordance with article 1 of Decree-Law no. 19/93 of January 23. In this way, the protection of the ecosystem of the river and Almargem lagoon must be guaran-teed by the competent authorities and the Guardians of Time made sure to make this very clear. From the above it is clear that all the biodiversity of the lagoon is extremely vulnerable and dependent on a good management of the water lines as well as its surrounding ar-ea. Cleaning up water lines and non-construction upstream can help mitigate some of the effects of climate change that have been felt. Thus, we challenged the local authori-ties to participate in a cleaning action in the water lines and lagoon, allowing the clear-ing and de-watering of the water lines and sensitized to the need to prevent the in-crease of the urban area.