ENVIROLMENTAL GROUP: FINAL REPORT.
LOCATION
The Canary Islands is situated 28°06′N 15°24′W / 28.1°N 15.4°W . Tenerife - 28°16′7″N 16°36′20″W. Gran Canaria - 27°58′N 15°36′W. This archipelago is in subtropical zone. All over the world at the same altidute are deserts, but in Canary Island there is not deserts.
The Canary Islands - Spanish archipelago is located on the east Atlantic ocean and just off the northwest coast of mainland Africa, 100 km west of the border between Morocco and the Western Sahara. And ofcourse more than 1500 km between Europe and these islands. Also the Canaries are a Spanish atonomous community with 2 provinces: 1. consists of La Palma, La Gomer, El Hierro and Tenerife with a capital Santa Cruz de Tenerife. 2. consists of Gran Canaria, Lanzarote and Fuertaventura with a capital Las Palmas de Gran Canaria, so it is the outermost region of the European Union.
The Canary Islands - consists of 7 larger islands (Gran Canaria, Fuerteventura, Lanzarote, Tenerife, La Palma, La Gomera and El Hierro) and a few smaller ones (Alegranza, Graciosa, Montaña Clara, Roque del Este, Roque del Oeste and Lobos).
We visited two of these islands - Tenerife and Gran Canaria, which are in the middle of Spanish archipelago. The distance between islands is about 75 km.
• Tenerife is the largest of the Canary Islands with a land area of about 2035 km² (2,034.38 km²) and 906,854 inhabitants, 43% of the total population of the Canary Islands. Island is located on theAtlantic ocean about 225 kilometers off the northwestern coast of Africa and about 1300 km from Europe. It is the most popular of islands (about five millionTouristsvisit Tenerife each year).
• Gran Canaria – is the third of the Canary Islands with a land area of about 1560 km² and it is the second most populous island of the Canary Islands, with population of 845,676 which constitutes approximately 40% of the population of the archipelago. Island is located on the Atlantic ocean about 150 kilometers off the northwestern coast of Africa and about 1350 km from Europe.
To sum up all these things, I would like to remaind 3 very important things:
• Canary Islands are realy Islands.
• This Spanish archipelago is subtropical area of Atlantic ocean.
• And the development of this archipelago have been made by European people.
The Canary Islands are situated on the African Plate. This is the same situation as with Madeira island and Cape Verde island.
GEOLOGY
GENESIS THEORY
All Canary Islands have volcanic origin, and some ones still having activity.
One of the first theories about the formation of the Canary Islands is called “up lifted block” (Spanish: blocoslevantados). That theory was proposedby ArañaSaavedra and others in 1976, and was dominating until the end of the 1970ies. Up lifted block theory states that each island is a block that was being raised about 40 million years ago, due to the shock of the collision of the African plate with the Eurasian plate. With that the magna was able topenetrate the ocean floor and start forming the islands.
Currently the prevailing theory is the Hot Spot theory. TheCanaryhotspot, alsocalledtheCanarianhotspot, is a volcanichotspotbelievedto be located at theCanaryIslands off thenorth-western coast of Africa. TheCanaryhotspotisbelievedto be underlain by a mantle plume that is relatively deep andhas first appeared about 60 million years ago.
The hot spot is located at a fixed location in the mantle,lying in a greater depth than the lithosphere. With the movement of the African Plate going from west to east, the hot spot continuously created new islands. The oldestislands can be found farthest away from the hot spot.
Lanzarote and Fuerteventura islands, counting about 20 million years, are older than La Palma and El Hierro, with 2 and 1.5 million years. The Canary hot spot doesn’t form a real “straight line”, like for example the more famous hot spot that created Hawaii.
The Canary Islands rose from the Jurassic oceanic crust associated with the opening of the Atlantic. Underwater magmatism commenced during the Cretaceous, and reached the ocean's surface during the Miocene.
Figure 5–Canary Islands and their Age in million years. Source: CEVIC
VULCANIC EVOLUTION
On what is today’s Tenerife Island threedifferent volcanoes first appeared: Teno, Anaga, and Adeje volcano.
After this one new volcano, called Las Canadas, was created and formed a large center at the heart of the island. Slowly the island formed a new configuration.
As a next step Las Canadas, with 5000 meters altitude much higher than today’s Teide,erupted and totally collapsed. This explosion formed a big caldera and the volcano disappeared. In the recent geologic pastthe volcanoTeideevolved in the former Las Canadas Caldera.
Initially Gran Canaria had two different islands and volcanoes. Then a new volcano called Tamaránunitedthe single fragments to one entire island. At the next stage a new volcano called RoqueNubloappeared. The current configuration of Gran Canaria is with a number of new volcanoes at the north of the island.
GEOMORPHOLOGY
The particular topography of the islands with their steep slopes significantly increases the probability for landslides. These landslides transportsediments towards the ocean, and furthermore have the potential to cause big tsunamis in Atlantic Ocean.
Due to the varying orientation of the island’sregions, as a consequence there are also different levels ofprecipitation. This diversity in environmental conditions eventually determines what kinds of vegetation and erosion processescan be found at that very spot of the island.
->CLIMATE
The Canary Islands are located in the Subtropical zone, very near to the East coast of the African continent. They have an abrupt relief and they are in contact with a cold oceanic stream.
Because of their location, the Canary Islands should have a dry and hot climate, but their insular conditions and the following factors make changes to this fact.
The Canary Islands have a special climatic condition with high contrast between zones in a small space. This special condition is a consequence of the location and the geomorphology of this archipelago.
The differences respond to two principal factors:
-Between islands: The islands in the East have not very high altitudes, that make the trade winds pass over without powerful ascent of air. In the other hand, the western islands have higher altitudes that make the trade winds ascend with a cooling produced by the thermal gradient.
-Between internal islands zones: The islands have a main difference in the precipitation and temperature between the northern regions and the southern regions. This fact affects all the islands and is due to the Foehn Effect and the directions of the trade winds, which collide with the northern slopes of the mountains and then go down by the South slopes.
General Conditions:
-Temperature: No extreme temperatures. (Only in zones of high mountain.)
-Minimum daily temperature contrast.
-High ocean influence except in high altitudes.
-Affected by the Atlantic High pressures.
-In the higher altitudes, the return of the trade winds affects with a strong West to East winds.
Specific Characteristics:
-Sea of Clouds effect, produced by the ascent of the air from trade winds when take contact with the island relief. The main consequence of the sea of clouds is a very high humidity and a total cloud cover in the north part of the islands between the 500 and the 1500 meters.
-Saharian Wind Invasions: They occur when the dry and hot Saharan wind masses cover the islands. They are more frequent in the East islands.
Global Facts in the Islands:
-In the northern parts: At low altitudes we observed a high oceanic influence with a very small thermal amplitude. At mid altitudes, between 600 and 1500, a very high humidity lower temperatures. At high altitudes, it is very dry and there are no precipitations except snowfalls in winter. The high altitude climate is the same on both slopes.
-In the southern parts: At low altitudes, there is a dry coastal climate. At mid altitudes, there is a dry climate with extreme storms from the South several times per year.
VEGETATION
As a consequence of mentioned geographical factors different vegetation areas with high diversity of species were formed. They are distributed according to altitude (vertically) and orientation (horizontally). Among them the most typical are coastal vegetation, thermophilous vegetation, laurel forest (laurisilva) and pine forest (pinar).
Canary Islands (Tenerife and Gran Canaria) have a well developed altitudinal gradient of vegetation. The most important environmental factors are altitude, orientation, wind exposure, temperature and precipitation, while on the other hand mineral composition of the soils do not vary much because of the volcanic origin of the island, therefore they do not present a critical role (Fernández-Palacios, 1992). Since the natural vegetation has been changed significantly in the past years, agricultural land use and urbanization should be considered as an environmental factor of vegetation as well.
Vegetation can be described according to following elevation zones:
1.) At the lowest elevation the coastal vegetation grows. Endemic palm trees (Phoenix canariensis) and semiarid vegetation can be found here. This vegetation type occurs up to 500 m in the northern slopes of the island and to much bigger extent in the southern slopes (cca. 1000 m). Species found here include Euphorbia canariensis, Euphorbia balsamifera and Euphorbia aphylla.
Coastal vegetation consists of halophyte communites as well, which form a narrow belt just above sea level, where plants need to be adapted to high degree of salinity of the soil. Stems and leaves of the plants are morphologically modified (succulent and fleshy), where saline water is stored to establish a balance with external conditions and avoid dehydration (The Canary..., 2011).
2.) Along the transition zone from 50 to 500 m, between the sea level coastal vegetation and laurisilva, thermophilous vegetation can be found. The species found here are common to lower and higher vegetation zones as well. These areas were highly agriculturally developed in the past, so the natarul vegetation is mostly damaged. Among others Phoenix canariensis, Dracaena draco, Pistacia lenstiscus, Olea europaea, Rumex lunaria can be found.
3.) Climate parameters on the island provide favourable conditions for subtropical laurel forest (Laurisilva) to grow (high degree of humidity, precipitation, stable temperatures). These conditions are fulfiled in the northern and northeastern slopes of the islands on the altitude of 500 – 1.500 m a.s.l. in areas where the Trade winds blow and form a sea of clouds. On the southern slopes of the islands the different conditions (low humidity) makes it impossible to grow. This kind of forest originated in ancient Tertiary forests of Mediterranean basin (15-40 million yr ago). During the weather changes in Quaternary the island provided niches where the Laurisilva could survive. From the ecological point of view it has a special importance, since it provides vast biodiversity (trees, shrubs, herbs, fauna,...) and high degree of endemic species. Representative species of laurisilva are Laurus azorica, Apollonias barbujana, Persea indica, Arbutus canariensis, Erica arborea, Myrica faya.
4.) Above the laurel forest the air is drier, the insolation is more intense and daily/seasonal temperature amplitudes are higher with a possibility of frosts and even snow. In these climatic conditions the pine forest evolved, ranging from 1200 to 2400 m a.s.l., depending the local conditions. Two types of pine forest can be distinguished, more humid one on the northern slopes and and drier one on the southern slopes, reaching a little lower altitudes. It consist of endemic Pinus canariensis with several other endemic species (The Canary..., 2011). In the past it was highly used in economic purposes.
5.) Reaching an altitude of 2000 m and above (as seen in Teide National Park) vegetation increasingly adapts to the special environmental conditions like strong winds, very low humidity level, scarce rainfall, high insolation, cold winters with hot summers and high daily/seasonal amplitudes.
Figure 1. Vegetation belts on the NE slope of Tenerife (Fernández-Palacios, 1992).
There is a difference in evolution stages of the islands. High elevation islands permit the development of distinctive vegetation types. Since the eastern Islands are older, they are more evolved and have lower altitudes, while the western Islands still offer even higher diversity with all the vegetation zones.
Environmental factors of soils
Different soil types have been developed due to the effects of vegetation, local weather conditions, and topography on volcanic materials. Each of the habitats grows on a specific kind of soil. Canarian pine forests grow on two kinds of fertile soil: ancient red soils because of high iron oxide content, and grey clay soils with low organic material content. Laurisilva occurs on soils with medium to low organic material above older soil types (WWF, 2011).
Natural forest vegetation provided favourable conditions for soils to develop. Since forests are able to capture the moisture of the clouds and prevent erosion, thicker layers of soil were developed. During the development of agriculture many forests were cut down and the soils were taken away, what caused an increase of erosion and losses of fertile soils. In last 50 – 60 years new forests were planted in order to reduce these consequences.
Threats for the vegetation
As the lowest altitude areas were highly agriculturally and economically developed, the pressure and the impact to the natural vegetation was the strongest. As yet some areas that contain intact vegetation can be found. Most of this places are included within protected areas with different types of protection.
A variety of factors can be identified as threatening problems for natural vegetation. Spreading of tourist resorts is one of the main threat. Fires are another significant problem with livestock grazing, crop planting and timber speculations as different reasons for them. With development of tourism, pollution and uncontrolled dump sites are becoming an important issue (WWF, 2011). As some invasive species were introduced in the past, they have to be mentioned as well.
Sources
- Fernández-Palacios, J., M., 1992. Climatic responses to plant species on Tenerife, the Canary Islands. Journal of Vegetation Science, Vol. 3, No. 5, pp. 595 – 602.
- The Canary Islands Bothanical Garden, 2011.
- World Wildlife Foundation, 2011. URL: http://www.worldwildlife.org/wildworld/profiles/terrestrial/pa/pa1203_full.html (quoted: 30th April 2011).
RESOURCES EXPLOITATION AND HUMAN IMPACTS ASSOCIATED IN HISTORICAL CONTEXT
Like any islands situated in the tropical zone, the Canary Islands represent an extremely dynamic system, manifesting a high sensitivity to external factors. The geologic and geomorphologic conditions along with the climate regime contribute to the formation of a resourceful environment that has been intensively exploited in the last centuries.
The concept of “resource” has often changed its meaning across time. For instance the location of the islands used to be a resource, as in the past the islands represented an excellent trade location, and strategic spots in the Atlantic. Nowadays, Canary Islands are perceived as an exotic location, attracting large numbers of tourists.
Considering the main aspects related to the geologic and geomorphologic evolution of Canary Islands, it has to be mentioned that during the agricultural society, the mineral fertile soils were the most valuable resources, allowing the development of tomato and banana cultivations. Today, the importance of soils has been replaced by the value of the volcanic landforms, as they represent an extremely important touristic attraction.
Moving towards climate, its value has been proven to be undeniable, although from different points of view. Before 1950, when the economy was based on agriculture, the Canary Islands climate provided favourable conditions for different cultivations, allowing the growth of exports. Once with the transition to a tourism based economy, the subtropical climate has given a low seasonality of the touristic activity.
The vegetation of Canary Islands in general, and of Tenerife and Gran Canaria in particular presents a very high diversity. Until recently, wood was considered a primordial resource, being used in almost every activity. In the last decades, society has orientated its interest on the protection and conservation of the biodiversity, leading to the creation of natural and national parks.
The Maspalomas Dunes represent the best example to emphasize the changes regarding resource approach. During the agricultural society, sand was not seen as a resource, but as a threat. It did not make sense irrigating it, therefore it could not be cultivated, and its mobility generated discomfort. As tourism grew, the sand dunes have become the most important natural resource of the island. Even though the resource itself did not change, there was a change of development perspective.
Development perspectives change according to historical and economic context. The fact that the Canary Islands have a very diverse environment offers them more flexibility. More flexibility results in less vulnerability.
Conclusion
As now have been mentioned all the environmental basic information and all the different landscapes of the islands a conclusion shall provide a broad-viewed outlook of what that eventually means for the future development of the Canary Islands.
Initially humans could basically be considered to be determined by nature (Friedrich Ratzel – Geodeterminism). At the example of the Canarys this can be made clear by referring to the location of the islands. When conquested by the Spanish it was used to harness the eastern trade winds to travel to America. Now, 500 years later the islands are attracting millions of tourists to spend their holidays here because of its climatic assets.
As suggested by many geographers, nowadays a separated consideration of society and nature and one-way cause and effect relations (as stated before) aren’t able any more to solve modern day problems, especially related to global change. With global change we mean globalization (e.g. mass tourism, dependency on oil) on the one hand and climate change (e.g. rising sea level) and decreasing biodiversity on the other hand. These influences cause huge pressure on the islands environmental systems and resources.
In order to investigate environmental issues on the Canary Islands, as an uppermost principle it has to be stated that by environment we don’t only mean nature with its ecosystems but also society (human impact). With the goal to create applicable and problem oriented knowledge, which eventually leads to future (and in the best case sustainable) paths of development, society and nature have to be investigated in a holistic and integrative way. In other words: The locations were society (e.g. settlements) starts to interact with natural ecosystems (e.g. Sand Dunes), the point of interest for a geographer dealing with environmental issues can be found. The following examples shall provide an overview of how holistically considered environmental issues can contribute to finding sustainable development paths in the future.
Sand Dune Ecosystem (Dunas de Maspalomas) - Conclusion
In the following part a short conclusion, about the “Dunas de Maspalomas” that were already being discussed in one of the previous chapters, is given.
· State of the Art in Duna-Research: Urbanization is destroying the very attraction it’s making money out of.
· That’s where economic development and environmental preservation attempts clash.
· Despite good knowledge about the age, formation and current yearly sand loss, we still have very limited knowledge about how this ecosystem really functions.
· If it hadn’t been for human impact since the 1950ies maybe we would lose sand the same rate we do now or even worse
· This is the same situation as we can find in many other ecosystem where humans are having impact and also on the global scale. à humans intervene in natural systems without knowing how they work nor how they will react when changing one input or regulator.
· On this position a call for creating a board of stakeholders, scientists, politicians and the tourist sector has to be made as Regional Government entities not only have the potential to harness their endogenous potential but also to develop a region sustainably (economic, social, ecologic).
Natural Hazard Research
As one field of research in which interactions between society and environment are being investigated is natural hazard (risk) research.
Risk = f [Hazardpotential (M, F), Damagepotential (Presence, Value), Vulnerability]
In the Formula Risk is being defined as the probability that a negative event will occur and cause damage. In Risk Research Risk isn’t necessarily negative and also stands for a new opportunity due to changing conditions. However in Natural Hazard Research Risk is being assumed to be harmful and therefore negative. The Risk is being defined by the Magnitude (M) and Frequency (F) of a certain (mostly natural) process (Hazard), by the Presence (P) and Value (V)of manmade objects or humans themselves (Damage), and by the Vulnerability of a certain society. The latter combines the Hazard- and Damagepotential and stands for the ability of a society to predict, cope with, resist and recover from a harmful event.
At the example of Tenerife the most prominent risk is due to its volcanic origin as was already mentioned in the report. Tenerife is on the verge of a huge explosive eruption and nobody really knows when this catastrophic event will occur and how much time current prediction technologies can provide in order to evacuate the island. Returning to the Risk-Formula it can be stated that the Magnitude of a volcanic eruption will be extremely high, the frequency however is extremely low. Furthermore the Damagepotential on the island is very high as there is a huge value accumulation especially on the coasts. Apart from the monetary values also many lives will be at stake in case of a volcanic eruption. Finally the formula leads us to the concept of Vulnerability. Even though on the Canarys there is an extensive net of seismometers that can detect volcanic activity accurately and fast, the ability of the society to cope with, or resist this harmful event have to be assessed as extremely low. Regarding the lack of any evacuation plan the consequences of one or multiple volcanic eruptions have to be estimated to be unimaginable catastrophic. Apart from volcanic activity, rising sea level due to global warming can be stated as another increasing threat to the tourist areas at the coasts of Canary Islands. Other areas that are affected by natural hazards are the villages in or close to the so called “barrancos” (valleys) due to fluvial flash floods, but also the coastal regions due to floods caused by storms or earthquakes.
Extensive Risk Management, for all natural and technological hazards that covers all populated areas of the island, is indispensible. Due to the high and still increasing accumulation of values and high population density on the islands in our opinion this kind of adaptation measure to Global Change would surely turn out to pay off in the future.
The Risk Management Cycle, as developed by Kienholz et al., is depicted below and shows the ideal process of Risk Management starting with Risk Assessment conducted by Risk Experts as well as Stakeholders. Without explaining the cycle more profoundly it can already be seen that the whole process is inherently dynamic and carried out transdisciplinarily.
Monitoring Biodiversity
It can be stated that the preservation of biodiversity on the Canary Islands is of high importance. In order to do so systematic monitoring of vegetation in all the different stages of the islands is an important tool to get a better understanding of the processes that take place in the ecosystems and further to understand the various effects of human impact on the environment.
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