SCIENCE ACROSS THE WORLD:
BIODIVERSITY AROUND US
THE BIODIVERSITY OF EL SALER
Antoni Cassany Penalba
IES Vicenta Ferrer Escriva. Valencia. Spain
This research project has been performed by 14-15 years old students of 3th year ESO (Compulsory Secundary Education) who attended an Environment Science course in our school. In May 2009, we travelled to the Natural Reserve of El Saler, located on the outskirts of our city, València, in order to make a field study of its biodiversity, especially plant biodiversity. El Saler is a natural area belonging to L'Albufera (i.e. coastal lagoon) National Park, located just 8 Km from downtown.
Our work is part of the "Science Across the World" project, an international organization in which schools from 150 countries have been "exploring science locally and exchanging their insigths globally" in many languages. Our students performed during the year 2009-10 a series of environmental science activities following the CLIL methodology (Content and Language Integrated Learning). Students had not a high level of English and the group was very heterogeneous. The project was also attended by the department of English. Our students learned new vocabulary while improved their English skills, particularly comprehension, writing and oral expression. Another important aspect was the collaborative work in which students took an active part in developing the project.
We worked the topic "Biodiversity around us". In this topic students explored the biodiversity of a small area near their home and become aware of the importance of biodiversity to humankind. The topic provides opportunities for students to make a survey of the plants and animals in a given area, study interesting species and its relationship with their own local culture. They could also investigate changes within the studied area over time through local media, interviews with older people and so on. In addition they could investigate the impact of non-native plants and animals on the local environment and learned some facts of the Spanish and international legislation to protectlocal biodiversity. This leads to them producing their own local action plan.
After exchanging their findings and views with students in other countries, students compare and discuss the responses received from classes in other parts of the world. It is also an oppotunity to share knowledge on different cultures of the participating schools and introduce our school and our city to students from other countries.
The main aspects worked were:
1. What is biodiversity?
2. Why biodiversity is important to us
3. Factors affecting biodiversity today
4. Addressing the issue
5. Exchanging information
6. Comparing information from other countries
This topic covers the following aspects of biology:
• An understanding of the concept of biodiversity and why it has become an issue today.
• The basic meanings of concepts like species, habitat and ecosystem.
• Observation and recording techniques to study biodiversity in a given area, through a basic habitat survey, organism identification techniques, and mapping skills using keys and scales.A previous work on this subject, not published, was written two years ago (spring 2007) by other students, (it can be seen in this PowerPoint file). In this file there is an introduction to our school and our city.
Where is "El Saler"?
Here you have 4 maps that could help you to locate "El Saler" and the area we studied. You can also use this GoogleEarth file
The Albufera Natural Park in Valencia is one of the most representative and interesting natural places of Valencia and its value has been recognized both nationally and internationally as a perfect example of the interaction between man and nature in the generation of life forms and exceptional landscapes.
The Albufera of Valencia, located about 15 kilometers from the southern end of the city, is the largest lake in the Iberian peninsula. The Albufera is a former marine gulf, now closed by a narrow strip of sand covered with a pinewood known as the "Devesa del Saler" which is the natural dam of the lagoon. Through this coastal belt there are three drainage channels or "Goles" (Pujol, El Perelló and El Perellonet) with gates that regulate the level of the lake and allow the flooding of approximately 18,000 hectares of land boundary involved in the cultivation of rice.
The rice cultivation was a fundamental system for conserving the biological richness of the Park since it supports a vegetation and associated invertebrate fauna that is the food base for many species of vertebrates, mainly birds. The rice is a complement to the lake natural resources as a vital feeding area during the winter and the migration steps.
The area around the lake has always been sparsely populated by the difficulty of cultivating the land and the incidence of malaria. In the last decades of the twentieth century, however, this former rural area became one of the most turistic areas of Valencia, generating major conflicts with the conservation of this natural area because of the increasing influx of visitors and the building of coastal tourist sites.
A mosaic of ecosystems
El Saler is located inside the Natural Reserve of L'Albufera, a coastal lagoon (in blue) surrounded by marsh vegetation (in dark green) and floodable lands -or marjal- where rice is grown (in light green). El Saler occupies a narrow border filled by forests of white pine (Pinus halepensis) between the Lagoon and the beach (in yellow).
In "El Saler" we can distinguish four different ecosystems:
A- Beach
B- Mobile dunes
C- Mallada (floodable lands)
D- Fixed dunes o pine forest (pineda)
The main ecosystems, from East to West, in L'Albufera Natural Park are:
Mobile dunes and beaches
Dune ecosystem has a high ecological value by the specialization of life forms that houses because of the extreme aridity of the environment as a result of sand permeability, high salinity, salty wind, high temperatures that can reach sand and the low consolidation of the substrate.
Some sections of this ecosystem were badly deteriorated and relegated to small dune alignments as a result of intense developing actions which took place in the 70s. Today we can find some of them in process of regeneration.
"Mallades" / Wetlands, intermitent marshes
Between the two sets of dunes there are depressed areas characterized by low permeability soils and the presence of salted groundwater near the surface. The different degrees of humidity determine the existing vegetation and, consequently, the animals who live in. But, as it has happened with other areas of the park, these areas have suffered degradation processes due to human action that have been significantly affected since they are specialized and sensitive ecosystems.La Devesa (pinewood)
The greatest botanical diversity of this environment favors the existence of different degrees of vegetation cover that will allow the consolidation of a highly diversed fauna. The value of this area remains significant as a good representation of Mediterranean vegetation on fixed dunes.
Albufera (Coastal lagoon)
Albufera lake is, together with Marjal and Devesa, one of the key environments of the Natural Park with an average size of about two thousand eight hundred hectares of which 350 are marsh vegetation. It must be distinguished, on the one hand, the free water area and, on the other hand, the muddy banks and bushes (locally called mates), whose combination enables the development of its characteristic diversity of plant and animal communities.
Our itinerary
On May the 13th, we trevelled by public transportation to "El Saler". Then we walked for 2 hours. Our itinerary had four stops:
In our track we could observe three different ecosystems and how different they were. We made a more detailed study of the preserved pinewood area (Stop # 3). Here you have our results:
1- Degradated pinewood, near the road and the Saler village
2- Pineda, preserved pinewood (We particularly worked in this area)
3- Mallada (floodable lands)
4- Mobile dunes
The first spot was a high deteriorated area, since it is located next to the village by the main road. The continuous tread of people has caused the disappearance of the majority of the plants species and a strong soil erosion. Basically it was a zone with white pines (Pinus halepensis) with a few grass plants.
Either we did not find many animals with the exception of a mouse corpse, the feather of a pigeon and some small spiders.
This was the first area we studied (left) and its more representavive plants (Right. click to zoom)
This area was a more remote zone of pine forest, far away from the road and much more preserved. Next to the pines (Pinus halepensis) we found shrubby plants such as the lentisc (Pistacia lentiscus), the Kermes oak (Quercus coccifera), the heather (Erica multiflora), the fan palm (Chamaraerops humilis), together with several herbs and climbing plants like the bindweed (Smilax aspera). The biodiversity was much higher than in the former stop. We also observed many animals like little birds, black beetles, wasps, butterflies, spiders and a praying mantis. It looked like a jungle because of the climbing plants: we had to pass through one to one, since the path was very narrow. The environmental conditions were very mild since inside the pinewood the sea wind didn’t blow, the temperature was more stable and humidity was higher.
This was the second area we studied (left) and its more representavive plants (Right. click to zoom)
In order to study this area, we made three teams. Each team made a field study of one area inside the pine forest: A standard area, a shadier place and a sunnier place, so we could find any differences.
2 A: Standard pine forest
Students explain their work
We chose an area 5 meter long per 5 meter large and studied its vegetal biodiversity.
Inside this area , the maximum number of different species found in an area of 5m x 5m was: 10 species. Each species covered a different area. The species # 1 and 2 (Rhamnus) were the most dominant and occupied most of the area. The species # 3 had also an important area covered. The others species were placed sparsely.
Here you have their scientific name and a possible common name in English.
Scientific name Common name 1 Rhamnus lycioides Palestine buckthorn 2 Rhamnus alaternus Italian buckthorn 3 Halimium halimifolium Yellow sunrose 4 Thapsia sp 5 Sedum sediforme Pale stonecrop 6 a species of the Poaceae family 7 Lagurus ovatus bunnytail, haretail 8 Unknown species 9 Juncus effusus Common Rush 10 Helicrysum stoechas
Everlasting
2 B : A shadier area.
Other team studied an area inside the pine forest. The ambience was much shadier.This area had less biodiversity.The whole area was occupied by white pines and bushes like Rhamnus lycioides, Pistacia lentiscusand Phirylea angustifolia). We also found climbing plants as Smilax aspera or Asparagus sp.
Students explain their work
2 C: A sunnier area
The third team studied an alterated area after a fire some years ago. There were no shadow. The plants were smaller and we found a great biodiversity. There were no dominant plants. The soil was not completely covered.
Students explain their work
AREA #3: The "Mallada"This was a very monotonous area with no much biodiversity. This area is sometimes covered by salty waters. There were no many plants that can support these conditions. In this area we found the corpse of a wild rabbit. We could'nt know why it was dead.
This was the third area we studied (left) and its more representavive plants (Right. click to enlarge)
Students explain their work
AREA #4: The sand dunesThe variability in environmental conditions is especially pronounced in sand dunes because of shifting substrate, burial by sand, porous nature of sand and little or no organic matter. The major factor affecting these changes is the establishment of vegetation that stabilizes the surface, adds humus, develops shade and reduces the severity of drought on the soil surface. Soil moisture The water content in sandy soils is one of the most important limiting factors in plant growth. Sandy soils have high porosity and after a rain most of the water is drained away from the habitat because of the large interstitial spaces between soil particles and the low capacity of sand to retain water. Soil and air temperatures On clear summer days the temperature of the surface layer of sand may reach up to 60°C.. In the evening, however, the situation was reversed. The thin hot surface layer of sand cooled rapidly- There is a large diurnal temperature range at the sand surface. Soil and salt content Salt spray is an important abiotic stress that affects plant and other biotic communities in the vicinity of sea coasts. These species have evolved traits that allow them to tolerate the effects of salt. Anyone who has visited a sea coast on windy days has experienced the landward movement of salt in the form of salt spray.
This was the last area we studied (left) and its more representavive plants (Right. click to zoom)
Students explain their work
Some of the most representative plants in the sand dunes can be seen in this slide show:
A complete set of photograps made by Cristina Barreda can be seen here
