restinga it is an extensive strip of sandy deposits that runs parallel to the beach line in the coastal zone of Brazil and several other countries. These sediments were deposited as a result of the advance and retreat of ocean waters during the recent geological period, the Quaternary, as a result of changes in sea level over the course of the time. Restingas are also important coastal ecosystems that develop on this fragile substrate.
Important for the preservation of other environments such as mangroves, for the protection of the dunes and for fixing the soil, the restingas are found threatened by environmental problems resulting from the advance of urbanization, climate change and the intensification of anthropic action on the Coast.
Read too:Cliffs — high walls with a steep slope that form on the coast
Summary about restinga
The restinga is an extensive strip of sandy deposits parallel to the beach line that were formed by successive changes in sea level in the Quaternary period.
It is also an important coastal ecosystem that forms in the transition between the sea and the continent.
It grows in the coastal zone of Brazil and several other countries.
The vegetation of the restinga is quite diverse, composed of herbaceous, shrubby and arboreal strata. It is subject to the influence of sea water, strong winds and relief.
It has sandy soils with low water retention capacity.
The fauna of the sandbanks consists of aquatic animals, such as crustaceans, and terrestrial ones.
They are very fragile ecosystems that are threatened by the intensification of climate change, by the advance of urbanization in the coastal zone and by anthropic activities in general.
Main characteristics of the restinga
Before studying the main characteristics of the restinga, it is important to know that there are different definitions and approaches to this concept.
In Geography, the restinga can be understood from a geological and geomorphological point of view as a sand strip formed through deposits of marine and fluviomarine sediments that occur in the coastal plain. The restinga is, in this sense, a very unstable and fragile feature that is arranged in the form of strings parallel to the coastline.1|
A very diverse vegetation cover can develop on the sandy soils of the restinga, which gives rise to an ecosystem characteristic of the coastal zone. These ecosystems, in ecology, are now also identified as restinga.
→ restinga location
The restinga is a coastal ecosystem that develops on the transition strip between the sea and the interior of the continent, that is, between humid environments and drier environments. The restinga, therefore, is located in the coastal zone of countries and continents. In Brazilian territory, the restinga is part of the Atlantic Forest biome and is present on a larger scale in the Northeast and Southeast regions.
→ Sandbank climate
There is no specific climate in which restinga vegetation develops, considering that the most important factor for its occurrence is the soil.
Thinking about the case of the Brazilian restinga, it occurs in areas with a tropical Atlantic climate.. This climate type is characterized by high air humidity, high incidence of winds, rainfall that arrives to 2,000 mm per year and high average temperatures ranging from 18 °C in the mildest months to 26 °C in the warmest months hot.
→ Restinga vegetation and flora
The vegetation of the restinga varies considerably according to the area, which is due to the instability of these ecosystems. The incidence of winds, relief and soil composition are factors that influence the development of plants in the coastal strip. The distance from the sea is also important, bearing in mind that the closer to the water, the more subject to the action of salinity and waves are the substrate and the species present there.
The vegetation cover of the restinga can be presented in the herbaceous, shrubby and arboreal strata.
Herbaceous vegetation: also called vegetation of beaches and dunes, it is formed by creeping plants or subshrubs that are up to 1 meter high. The action of sea water is more intense on this stratum.
Shrub vegetation or “scrub”: formed by herbs, vines and plants with a height between 3 and 5 meters. These are bushes with a twisted appearance, which may or may not form bushes. Bromeliads and orchids can be part of the flora in these areas.
Tree vegetation: the restingas tree stratum is composed of low forests and tall forests, with a canopy between 5 and 20 meters high, respectively. Tall forests, mainly, can form on flooded soils. These formations are further away from the beach line and, unlike the previous ones, are characterized by the presence of litter in the soil and greater accumulation of organic matter. Bromeliads, orchids, guanandi, içara and box are some of the plants found in this stratum.
→ restinga fauna
The restinga fauna, when compared to other ecosystems, consists of a small number of species. Furthermore, there are animals that are part of other environments, that is, the fauna present in the restinga also lives in other domains, such as the Atlantic Forest and the Cerrado, in the case of Brazilian territory.
Birds such as swallows, red-faced parrots and owls; marine animals, such as crustaceans and turtles; insects; reptiles; and mammals such as the otter and the black-faced lion tamarin are the main examples of the sandbank fauna.
→ restinga soil
The restinga has sandy and poorly consolidated soil, which confers great fragility to its structure and to the environment as a whole. In the Brazilian restingas, the soil is predominantly composed of quartz sand, which characterizes the coastal plains of the country. In addition to their unstable structure, these soils have a very low water retention capacity, and the formation of organic matter is low or null. For this reason, these are soils with low chemical fertility.
→ restinga hydrography
Restingas are geomorphological forms and ecosystems typical of the coast. Consequently, are environments bathed by the oceans and that suffer the interference direct phenomena such as the tides. Located on the coastal plains, the restingas are influenced by rivers, streams and other courses originating from the mainland and flowing into the sea.
sandbank formation
Considering the restinga as a geological formation, its origin is associated with the movement of advance and retreat of sea waters over the coast as a result of the variation in the level of the oceans in the recent geological period. This process was responsible for the deposition of sediments dating from the Tertiary and Quaternary periods in the coastal zone, generating large strips parallel to the beach line. On these sandbanks of the coastal plain and inland, on the coastal terraces, sandbank vegetation settles down.
See too: Lagoons — depressions that harbor fresh, brackish, or salt water
What is the importance of the restinga?
The sandbank ecosystem holds an important portion of coastal biodiversity, serving as habitat for both marine and terrestrial species. This training it also acts as a protection for other ecosystems of transition, like the mangroves, against the advance of sea water. The restinga is also important for the protection of the dunes present in these environments, in addition to preventing the process of erosion caused by sea water and help to fix the sediments in the area coastal.|2|
Restinga in Brazil
the restinga is present in the Brazilian coastal zone in association with the Atlantic Forest biome, which extends from the Northeast region to the South coast. This ecosystem can be found mainly in the states of Alagoas, Sergipe, Bahia, Espírito Santo, Rio de Janeiro and São Paulo. On a much smaller scale, the presence of restinga is also identified in the amazon biome, particularly in the states of Pará and Amazonas.
A 2009 resolution by the National Council for the Environment (Conama) established the ecological definition of the restinga, as well as its plant composition, which is the one we are studying here. Recently, a bill proposes to change the Brazilian Forest Code for the classification of sandbanks as Permanent Protection Areas (APP), due to the fact that its vegetation helps to fix the dunes and stabilize the mangroves. This modification represents flexibility in the protection of this ecosystem.
Environmental impacts and environmental conservation of the restinga
There are several problems that affect the restinga. The advance of urbanized areas over the coastal zone, the irregular disposal of garbage, the inadequate management of urban and industrial effluents and the intensification of human activities are factors that jeopardize the maintenance of numerous coastal ecosystems around the world, such as the sandbanks. Another major problem affecting the restingas is climate change, which, through the melting of glaciers, has gradually caused the level of the oceans to rise.
The fragility of the restingas potentiates the effects of environmental problems on the ecosystem, which reinforces the need to conserve them. Many restinga areas were transformed into national parks in Brazil, which means that they became areas of integral protection under the administration of federal agencies.
Considering these aspects, some of the necessary measures to conserve restingas in Brazil and the world are the following:
expansion of conservation areas along the coast;
awareness of the population so as not to damage the soil and vegetation in these areas;
disposal of garbage in appropriate places;
elaboration of policies for the protection and recovery of coastal ecosystems.
Solved exercises on restinga
question 1
(Unicamp)
Restingas can be defined as sandy deposits produced by current coastal dynamic processes (strong drift currents coastline, and may interact with tidal currents and river flows), forming elongated features, parallel or transverse to the line of the coast. They may present local reworkings associated with wind and river processes. When stable, the restingas form the “sandbank plains”, with the development of herbaceous and shrubby and even arboreal vegetation. Restingas are areas subject to erosive processes triggered, among other factors, by the dynamics of coastal circulation, by the rise in relative sea level and by urbanization.
(Adapted from Celia Regina G. Souza and others. Restinga: concepts and use of the term in Brazil and implications for environmental legislation. São Paulo: Geological Institute, 2008.)
It is correct to say that the sandbanks existing along the Brazilian coastline are areas:
A) little overloaded coastal ecosystems, due to the way in which human occupation occurred, with the urbanization process.
B) where the vegetation cover occurs in mosaics, found on beaches, sandy ridges, dunes, depressions, mountains and plateaus, without presenting important physiognomic differences.
C) susceptible to coastal erosion caused, among other factors, by wide zones of sediment transport, relative sea level rise and accelerated urbanization.
D) where the sandy soil presents no difficulty in retaining water and accessing nutrients necessary for the development of herbaceous vegetation cover on beaches and dunes.
Resolution:
Alternative C.
The restingas are subject to coastal erosion by the constant action of sea water, whose level has increased by problems such as climate change and human activities such as urbanization accelerated.
question 2
(Ufal) Sandbanks are relief features observed in various places on the planet, regardless of latitude. In the state of Alagoas, many restingas are observed. These are so-called “azonal” reliefs.
What can be said about sandbanks?
1) Sandbanks are geological faults that are observed in coastal areas that were filled by river sediments; a typical example is the Mundaú lagoon.
2) Restingas are coastal sandy sedimentary formations, of recent origin in the geological time scale, which sometimes take the form of plains and bars.
3) Restingas constitute coastal ecosystems determined, above all, by soil characteristics and marine influence; are ecologically fragile environments.
4) The vegetation established on the restingas must be preserved, as it constitutes an impediment for the winds to remobilize dunes that commonly exist on them.
5) Sandbanks are landforms resulting from folding that occurred in sedimentary land in coastal areas and that underwent strong human alterations.
They are correct:
A) 1 and 2 only
B) 2 and 5 only
C) 1, 2 and 3 only
D) 2, 3 and 4 only
E) 1, 2, 3, 4 and 5.
Resolution:
Alternative D.
Items 1 and 5 are incorrect for the following reasons:
1) Sandbanks are not filled geological faults. They are, in reality, sedimentary deposits that were formed by the advance and retreat of the sea.
5) The restingas form on the coastal plain, with no correlation with the folds, which give rise to the mountainous relief.
Grades
|1| SANTOS, A. R. Word: restinga. CPRM – Geological Survey of Brazil. Geological Glossary. CPRM, 15 Jul. 2018. Available here.
|2| IEMA. On Restinga Forest State Day, Iema emphasizes the importance of preserving the biome. IEMA – Institute of Environment and Water Resources, 28 Apr. 2021. Available here.
image credits
[1] Halley Pacheco de Oliveira / Wikimedia Commous (reproduction)
By Paloma Guitarrara
Geography Teacher