Deforestation Affects Wildlife as well as Climate

            Deforestation has always been a topic of discussion but now the conversation is moving towards how much more damage it is causing to wildlife, both inside and outside deforested areas.  Deforestation heavily targets tropical areas and are of great concern because they hold the world’s largest biodiversity, but it affects wooded areas all over the globe.  According to the World Wildlife Fund, we lose about 18.7 million acres of forest each year and deforestation, as well as forest degrading in general, attributes to about 15% of all greenhouse gas emissions (1).  The best-case scenario to reduce the number of species in decline, or harmful species increase and to not add further carbon emissions into the atmosphere, there needs to be a significant decrease in the amount of deforestation happening all over the world.  This is going to be an incredibly difficult task when poorer countries are considered.  Most of the deforestation is happening in poorer countries where they are trying to keep up with an increasing population and take part in the global economy.

Monarch butterflies in their wintering grounds in the Biosphere Reserve of Mexico
Source: https://phys.org/news/2018-10-deforestation-winter-habitat-mexican-monarch.html

As seen in Mexico, the amount of illegal logging has reduced the monarch butterfly’s wintering grounds, San Felipe de los Alzati, by a significant amount (2).  The canopy in these forests is needed by the monarch butterfly when they stay for the winter.  The canopy acts as a blanket to keep the butterflies warm as they clump together on the tree’s bark.  The biggest concern in deforesting their wintering area is that, as their numbers decline, fewer can make the migratory trip.  Since no butterfly survives the trip both ways, they need high numbers to keep up the possible chemical trail that leads them along the right migratory path (2).  With the rate of decline seen in the monarch butterflies, they could very well become endangered or worse, due to deforestation.  Species are also going massively extinct due to deforestation in Haiti, where 42 of their 50 largest mountains have lost their primary forest cover (3).  Surveys of the mountaintops show that vertebrates are disappearing along with the trees, further showing the effect humans are causing on biodiversity.  Species usually go extinct once the last of their habitats are gone, but in the case of Haiti, species are going extinct because there is low forest cover.  The areas haven’t been destroyed entirely and aren’t bare, yet species are dying off (3).  The opposite effect is being observed with the Aedes Aegypti mosquito, the mosquito that can carry the Zika virus, yellow fever, dengue, and the Chikungunya virus (4).  This mosquito does not live in swamps or underground where you’d find most mosquitos; they thrive on man-made environments.  In places like water filled tires, water barrels, and plastic containers, the mosquito will reproduce and can increase the population which will increase the risk for any of the diseases it carries.  Not only does deforestation lead to more human-made environments, but the deforested areas tend to be hotter, with little to no tree cover to moderate the temperature, which affects the mosquito’s life cycle.  With the increase in temperature, the time between the blood-feeding stage and egg-laying stage in a female mosquito’s life is shortened a considerable amount (4).

The Cerrado
Source: https://www.worldwildlife.org/places/cerrado

            Deforestation is also having a major effect on our climate.  Forests are major carbon sinks, absorbing large amounts of carbon dioxide to undergo photosynthesis.  Cutting down these forests releases the carbon dioxide stored and reduces the amount of area that can absorb the carbon dioxide out of the atmosphere.  Once other gases such as methane and nitrous oxide are factored in, the land humans use has twice as much radiative force of carbon dioxide (5).  Thinking of deforestation in this way shows how much more of an issue clear-cutting large swaths of forest is which could potentially become a problem for the Amazon as Brazil proposes a change to an article in its Forest Code.  Until 2012, private landowners in the Amazon region were required to set aside 80% of their property and keep native vegetation intact.  Recently a proposal to change the Forest Code would allow these private landowners to reduce the 80% of land they were required to maintain to only 50% of land.  If this change were to be legalized, anywhere from 7 million to 15 million hectares of land would become deprotected and be legally cleared.  It would also impair parts of the ecosystem that are needed by society such as water, biodiversity, and the increase of greenhouse emissions (6). On top of the threat to the Amazon, a savanna region that shares a border with the Amazon is more heavily deforested. This area is called the Cerrado and is about 50% deforested compared to the Amazon at 18% (7).  Due to this area’s heavy deforestation, it is thought to be the cause of the decrease in rainfall in the Amazon.  The extreme loss in vegetation means there are fewer plants contributing water into the evapotranspiration cycle, which means less rainfall overall.  The plants within the Cerrado are also adapted to the savanna biome and have deep roots that are able to pull groundwater up when there is a lack of rainfall.  A study done in 2013 found that there was about 3% less water participation in the cycle, adding up to a total of 14 billion tons of water lost (7).

References

1-     Deforestation and Forest Degradation. (n.d.). Retrieved from https://www.worldwildlife.org/threats/deforestation-and-forest-degradation

2-     Stevenson, M. (2015, August 25). Deforestation in Mexico butterfly reserve more than triples. LA Times. Retrieved from www.latimes.com

3-     Lundeberg, S. (2018, October 29). Animal species becoming extinct in Haiti as deforestation nearly complete. Science Daily. Retrieved from www.sciencedaily.com

4-     Mooney, C. (2016, February 3). The hidden environmental factors behind the spread of Zika and other devastating diseases. Washington Post. Retrieved from www.washingtonpost.com

5-     Hadlock, L. (2017, September 5). Deforestation long overlooked as contributor to climate change. Science Daily. Retrieved from www.sciencedaily.com

6-     Fundação de Amparo à Pesquisa do Estado de São Paulo. (2019, January 4). Revised Brazilian forest code may lead to increased legal deforestation in Amazon. Science Daily. Retrieved from www.sciencedaily.com

7-      Mooney, C. (2016, April 4). This huge region of Brazil is even more deforested — and less protected — than the Amazon. Washington Post. Retrieved from www.washingtonpost.com