Impacts of Rainforest Deforestation

In my last post I have explored some of the main causes leading to deforestation and the clearing of large areas of land of other activities. Most of the world’s deforestation activity occurs in rainforests. So why should we not cut down the trees in the rainforests? This post aims to explore the impact locally as well as globally.

Biodiversity

The global scale conversion of rainforests to agricultural land is undoubtedly a major driver of local biodiversity loss in both fauna (Figure 1) and flora where in turn has an impact on ecosystem functioning (Steffan-Dewenter I.et al., 2007). Having the largest amount and the highest diversity of species (in 1ha in the Amazon there are more species of plants than the whole of Europe! (GREENPEACE)) It is highly likely that with the loss of their habitat these species will become extinct due to their endemic distributions making them susceptible to any environmental change. Adding to this, there are many species that are yet to be discovered and documented and this is extremely important to medicine as a huge number cures have become form rainforest plants (WebEcoist).

Figure 1: Some of the fauna in Costa Rica (The Costa Rican Times)

One example of ecosystem services that are going to be impacted in the long run due to deforestation, is tree pollination. Priess J.A. et al., (2007) suggest that there will be a decline in the pollination services in relation to forest conversion directly reducing 18% of coffee yields that in turn will reduce the net revenues up to 14% in the next 20 years (Figure 2).

Figure 2: The Asian giant honeybee, Apis dorsata, is one of a number of pollinators of coffee in southern India (ETH)

Climate

The Amazon basin has the drainage basin area of about 7 million km² making it the biggest watershed in the world. It contributes 13% of the total runoff of the globe in to the oceans. In addition to this, 50-60% of the precipitation of the area is attributed to the evapotranspiration (Figure 3) of the flora of that basin and thus having a large impact on the energy as well as the water balance regionally and globally. In the scenario of severe deforestation, and thus a degree of land restructuring will alter the atmosphere dynamics with water flux weakening (D’Almeida C. et al.,2007).

 



Figure 3: Evapotranspiration in Western Congo Basin, Gabon

 

In the case of the Northern Hemisphere circulation, it has been observed that there is statistical significance between deforestation effects on the NE Atlantic winter rainfall that could extent towards Europe (Gedney N. & Valdes P. J.,2000)

The deforestation in Southeast Asia resulted to the decrease in precipitation that was observed outside the deforested area through winds. Werth D. & Avissar R. (2005) observed a proportional relationship between the impact of the magnitude and the degree of deforestation.

The storage of carbon also changes by deforestation which in turn has an impact in the global climate. Carbon release through forest degradation in addition to deforestation, is the 2^nd largest emission of greenhouse gas (Soares-Filho B. et al., 2010). 50% of CO₂ emissions are a result of forest fires and the rest are from respiration of organic material in the undergrowth (Van Der Werf G.R. et al., 2009).

Flooding & Mudslides

One of the characteristic of the tropics is daily rainfall and hence RAINforests exist there. The biome has developed and adapted to the heavy rainfall through specialisations resulting to ¾ of the water from precipitation to be interrupted by vegetation. With deforestation, there is little vegetation to control water flow resulting to severe flooding. Flooding also causes mudslides (Figure 4) where the soil becomes loose with the absence of roots leading to these two devastating effects. Furthermore, aquifers become depleted since there are decreasing infiltration rates and the water reaches the oceans as runoff. The decrease of the essential fresh water in the aquifers is a main problem for the ever growing population the tropics (Hilderman R., 2010).

 

 

Figure 4: Heavy landslides claiming lives in Malaysia (THE WATCHERS)

 

In general deforestation destructs the healthy functioning of the biome and has severe effects globally as well as locally on the environment and the ecosystem services it provides. The most likely to be impacted by deforestation in short term are the surrounding population where in most cases are from developing countries and thus increasing the impact due to poor infrastructure.



Why do we cut down rainforest’s trees?

 

Deforestation is one of the factors contributing to the force of human activity to become greater than the natural force – anthropocene. Deforestation is defined by the Oxford Advances Learner’s Dictionary as ‘the act of cutting down or burning the trees in an area’ with the perfect word example of ‘land erosion caused by widespread deforestation’

 

As mentioned in some of my previous posts with the changes of forest cover, major services delivered by the rainforest ecosystem are affected negatively such as the regulation of the climate, the storing of carbon, the supply of water and the highest biodiversity richness that describes the biome (J. A. Foley et al., 2005). So why do people keep deforestation rainforests in an unsustainable manner?

 

On a global scale, deforestation is responsible for an 80% loss of previously forested land. Deforestation is the main threat to rainforests around the world. An astounding 90% of the rainforest in western Africa has been lost due to deforestation since the 19^th century. The rainforests in the other 2 major regions (South America and South Eastern Asia) have also been destructed by deforestation (WPF).

 

The causes of Deforestation are similar across the world. Bjorn Lundgren (1985) pointed out that at a national level, people need to clear new land for agriculture and wood for various purposes. Nonetheless, subsistence farming accounts for a small portion of the rainforest destruction. Most of deforestation occurs for commercial agriculture such as the conversion of rainforest to Palm Oil (Figure 1) plantations in Southeast Asia and the soybean plantations in the Amazon basin.
 

Figure: Oil palm plantation adjacent to native rainforest (TBP)

 

Logging (Figure 2) has an important role in forested land loss. Even though it was designed to be a sustainable way of harvesting trees in most cases it is not true. In Southeast Asia, there is a high number of tree species that can be logged (10-20 /ha) leaving a heavily destructed ecosystem with this practice. In addition to this logging can have collateral damage to the rainforest by clearing some spaces for the tracks and platforms (Y. Malhi et al., 2013).
 

Figure 2: Tree felled (illegal logging) in Masoala National Park, Madagascar (WildMadagascar)

In the South American rainforests one of the primary cause of deforestation is the clearing of land for cattle pasture or as some may call it ‘hamburger ranches’ (Figure 3). The Brazilian Amazon was reduced in forested land by 38% from 1966-1975 for cattle ranching. By 2003 Europe’s imports of processed meat was 74% from Brazil from which 80% was coming from the Amazon (R. A.Butler, 2010). In 2010 the extent of deforestation in the Brazilian Amazon reached the area of 740 000km² (M. Egler et al., 2013).
 

Figure 3: Brazilian beef barons claim to be protecting Paraguay's Indian lands – by turning them into ranches (theguardian)
 

Deforestation methods include the process of ‘slush and burn’ which is the cutting of trees in addition to burning them to reduce to clear the land. These localised fires may sometimes escape their original plot resulting to devastating effects by reducing the forested land and hindering local activities due to the black smoke (R. A. Butler, 2010).

 

Other causes of deforestation include open cast mining (Figure 4) where large areas of forest were cleared for their subsistence, fuel wood and building material (Amazon Basin 1980s) (R. A. Butler, 2010). Colonisation has also played an important role in the well-being of rainforests. Vast areas of rainforests across the world where exploited by the arrival of the invaders.
 

 

Figure 4: Explosion at a mine in the Amazon Rain Forest, Ecuador (ConstructionPhotography)
 

The map on Figure 5 shows the change in forested areas over the period of 2000-2012. The area of the tropics exhibit the loss forest at the rate of 2101 km²/yr. A reduction in deforestation was observed in Brazil but the increasing loss of forest in other countries around the world offset this reduction (M. C. Hansen et al.,2013) You can use the software to look in to the areas in more detail here.

 

Figure 5: The map shows forest change from 2000-12. Green areas are forested; red suffered forest loss; blue showed forest gain; pink experienced both loss and gain (BBC)

It is estimated that there is a linear relationship with deforestation and economic growth. There is some hope that with different environmental policies deforestation will be reduced (J. Hargrave & K. Kis-Katos, 2013) In my next post I will be discussing the effects of deforestation.

'The Pale Blue Dot'

This is a break from my typical posts on forests. I came across this video through a friend’s post on facebook and I though it is worth posting since it motivated me to continue caring about one another and become more passionate about caring for the environment.

This is a video (THE SAGAN SERIES - The Pale Blue Dot) demonstrating the importance of our planet for our existence and that there is no one to save us from ourselves. The astronomer Carl Sagan narrates this video very effectively in my opinion to alert the viewers and to think about the way forward.

Enjoy!!

The following post will be on the destruction of the Rainforest biome by deforestation.

Rainforest Ecosystem Services

Rainforests have been providing ‘amenities’ to humans since the beginning being the foundation of the existence of the indigenous people. The ‘jungle’ supplied our ancestors with all the goods ranging from wood, animals and plants to clothing, medicines and pigments. After the passing of millennia, the close association to the services provided by rainforests did not fade (Rainforest Alliance). Rainforests across the globe provide services to humans that are of enormous economic value. They are frequently divided into 4 categories (Harvard School of Public Health):

Provisioning

According to UNEP 2011 yearbook, 1.6 billion people around the world have a close dependency on forests. Rainforests provide raw material for the inhabitants of the surrounding area to survive with fresh food from land or the fisheries, pharmaceuticals and wood for construction or fire.

On a global scale, there are renewable forest goods such as medicines where 70% of the drugs are natural chemical models , valuable timber, and surprisingly enough natural pesticides that humans are so in need (Rainforest Conservation Fund) and loads of varieties of exotic fruits (Figure 1) and of course chocolate!

Figure1: Rainforest Fruits (Rainforest Fruit Farm)

Regulating

Rainforests act as carbon sinks where the lock they lock CO2 from the air and thus removing some of the CO2 from the air that would contribute to global warming but they also give out O2 vital for respiration. This is a service benefiting the human well-being on a global scale (Rainforest Conservation Fund) (WWF).

The hydrological functions are positively regulated by the rainforests. Devastating outcomes are prevented such as erosion and landslides, flooding as well as desertification. This is because the water flow is regulated within the biome through watersheds and surface runoff in addition to regulating the water quality (Rainforest Conservation Fund) (Rainforest Concern).

Figure 2: Landslide in Papua (MONGABAY)

Supporting

The majority of rainforests are act as the so called ‘closed loop system’. They have very little inputs and outputs. As follows, they should be able to make their own nutrient to ‘feed’ the plants that thrive there. The nutrient cycling in the rainforest is very efficient with the different biodiversity and range of plant chemical composition they have the opportunity to exploit the environment. The disruption of this system will lead to the loss of the nutrients and the death of the rainforest (Rainforest Conservation Fund)

Rainfall patterns are influenced by the environmental conditions created by rainforests. The cloud cover as well as the humidity can affect other regions of the world thus supporting weather conditions.

Pollinators pay an important role in supporting the life in rainforests (Figure 3). Due to the vast number of plant species there are some pollinators that are specific to certain plants. Any reduction in ecosystems of rainforest can have a serious impact on the regeneration of the rainforest in addition to loss of species (Rainforest Conservation Fund).

 Figure 3: Glossophaga soricina, nectar-feeding bat smothered with pollen from a flowering tree – Palo Verde National Park, Costa Rica (cosmos)

Cultural

Rainforests are critical in society. They are the natural heritage of the local people with high spiritual and religious significance. On a more global scale, the jungle is a natural laboratory where it can contribute in different kinds of research from climate and natural systems to soils, biological and medical. The non-destructive harmonic coexistence of some human societies living in rainforests can provide an inside on their way of life through their agriculture and husbandry. The can also provide recreational activities through eco-tourism. The aesthetic value (Figure 4) is beyond measure either through air or through land (Rainforest Conservation Fund).

Figure 4: Santa Elena Cloud Forest Reserve (NatGeo)

Locally as well as globally, the services provided by the rainforests are of great value and the loss of them may cause irreversible effects to the climate, environment and human kind.