Effects of Deforestation in Madagascar

Abstract

Human-transformed land through habitat destruction causes negative long term changes to Earth's biodiversity and ecosystems. Deforestation and forest fragmentation are detrimental to all life, including humans. Forest fragments have been shown to have decreased animal residency and increased isolation. Fragmentation also greatly decreases the richness of plant species and nutrient retention. Deforestation and fragmentation is usually driven by economic development, agricultural activity, population pressure, and trade. However, in eastern Madagascar, deforestation is caused by smallholders' agricultural tavy system (slash-and-burn agriculture). This system destroys Madagascar for its human populations as well as many wild species, including Lemurs. Deforestation and fragmentation have caused lemur populations to greatly decrease. Local lemur extinctions have occurred, and the remaining populations have become restricted to forest fragments. To improve the livelihood, sustainability, and well-being of households, agricultural practices need to be transformed to permanent systems which do not undermine soil fertility, will produce enough crops for the local population, and is able to coexist with the remaining forest, such as hydroponic greenhouse farming.

Keywords: deforestation, fragmentation, lemurs, farming

Effects of deforestation and forest fragmentation on lemurs in Madagascar

Deforestation and forest fragmentation are detrimental to all life, including humans. All life on Earth depends on healthy forests for food, clean air, healthy water cycles, etc. When a forest is being destroyed for short term gain, it is difficult for some to comprehend the long-term consequences because they are not immediately felt. A synthesis of long-term experiments conducted in a wide variety of ecosystems showed that fragmentation strongly reduced species richness of plants and animals across experiments, often changing the composition of entire communities (Haddad et. al, 2015).

Deforestation is driven by economic development, agricultural activity, population pressure, and trade (Leblois, Damette, & Wolfersberger, 2017). Previous research failed to identify trade as a major factor in deforestation, however, there is empirical evidence linking increased deforestation to international trade (Leblois et al., 2017). In many countries, the drivers of deforestation are the demand for forest products and large-scale agribusinesses, but in eastern Madagascar, a main driver of deforestation is caused by smallholders' agricultural expansion to grow rice using the tavy system (slash-and-burn agriculture) (Urech et al., 2015). The smallholders use slash-and-burn agricultural practices to grow rice, which is vital to the economic livelihood of most of the local households as well as an important cultural practice (Desbureaus & Brimont, 2015). However, slash-and-burn agriculture will not only destroy Madagascar for its human populations, but the loss of habitat and fragmentation caused by the tavy system reduces habitat quality, connectivity, and population viability for many wild species, including Lemurs (Qu©m©r© et al., 2010).

Literature Review

Human-transformed land through habitat destruction, deforestation, and forest fragmentation causes negative long term changes to Earth's biodiversity and ecosystems (Haddad et al., 2015). Forest fragments have been shown to have decreased animal residency, increased isolation, and reduced movement among fragments, which negatively affected recolonization after local extinction occurred. In addition to the effect fragmentation has on animal species, the richness of plant species and nutrient retention is shown to have been greatly reduced. An analysis of the largest and longest experiments, which include disparate biomes and cover five continents over a span of 35 years, revealed strong evidence of temporal lags in extinction, also known as extinction debt, in forest fragments. An immigration lag was also observed along with reduced richness, which means that fragments are slower to have species socialization. In addition, ecosystem function debt, which includes changes to plant and consumer biomass as well as delayed changes in nutrient cycling, was observed to be caused by fragmentation (Haddad et al., 2015).

In many countries, deforestation occurs due to population density, economic development, agricultural activity, and trade (Leblois et al., 2017). However, in Madagascar, one major driver of deforestation and forest fragmentation is the tavy farming system used by smallholders for subsistence needs (Urech et al., 2015). Smallholders destroy and divide the forest to grow rain-fed hill rice. After a section of forest is destroyed, the soil to grow rice has only enough nutrients for one season, and what is left is used to grow manioc or sweet potato next. Farmers use the strategy of long fallow periods to maintain soil fertility, however, this only lasts for up to 10 years for those closest to the forest, and 5 years for farms farther from the forest. The practice of the tavy system undermines the security net of the smallholders. Despite introducing alternative agricultural practices, strictly defined nature conservation, and community based forest management frameworks, deforestation has continued. It seems smallholders resist abandoning the tavy system because the exploitable resources of the forest are not beneficial enough. Some of the reason are due to the lack of infrastructure which would allow non-timber forest products to be exploited, missing institutional framework and regulations, and limited market access. In addition, illegal logging prevents the opportunity for ecological sustainability (Urech et al., 2015).

Due to the decimation of Madagascar's forests, it is considered a biodiversity hotspot (Ganzhorn, Lowry II, Schatz, & Sommer, 2001). Hotspots are environments with endemic species and exceptional species richness which has lost greater than 70% of their original primary vegetation. Through deforestation and forest fragmentation, Madagascar has lost many native large animal species, and those that are left are not likely to be able to sustain viable populations past 2020-2040. Empirical data on fragmented forests from 20 - 40 years ago shows evidence that lemur populations consisting of less than 40 adults did not survive. The remaining costal forest fragments are too small for larger lemurs, and there are very few forest areas left in central Madagascar which would be able to sustain the surviving lemurs (Ganzhorn, 2001).

Qu©m©r© et al. (2010) investigated how forest fragmentation impacted the genetic patterns of the golden-crowned sifaka (Propithecus tattersalli). Genetic diversity is vital for organisms to adapt to environmental changes and for long term viability (Clarke, Gray, Gould, Burrell, 2015). Genetic diversity is rapidly lost in smaller populations, and in isolated or fragmented habitats, this loss is intensified (Clarke et al., 2015). The golden-crowned sifaka is a larger, social species of lemur whose habitat is exclusively in the north-eastern Darania region of Madagascar. It was found that the genetic diversity of the golden-crowned sifaka appeared to be greater than expected being that this species has such a small range and has the most fragmented habitat out of all the lemurs. Despite these surprising findings, there is cause for concern due to the installation of a gold-mining company as well as a national road in the Darania region. There is fear that these developments will further devastate the remaining forest fragments and possibly have a disastrous effect on the golden-crowned sifaka (Qu©m©r© et al. 2010).

In the southern regions of Madagascar, Clarke et al. (2015) studied the genetic variability of the endangered ring-tailed lemur (Lemur catta). The ring-tailed lemur occupies diverse habitats and has behavioral and ecological flexibility. However, due to deforestation and fragmentation, their population numbers are low, local extinctions have occurred, and the remaining populations have become restricted to forest fragments. This also restricts genetic diversity and raises the risk of extinction (Clarke et al. 2015).

Clarke et al. (2015), like Qu©m©r© et al. (2010), found no significant loss of genetic diversity. However, Clarke states the importance of considering the possibility that the data could reflect an earlier time period before intense habitat fragmentation. Due to the behavioral and ecological flexibility of the ring-tailed lemur, Clarke believes it is possible that their populations are experiencing a time-lagged response before a dangerously probable loss of genetic variation. Like the golden-crowned sifaka, ring tailed lemurs face the dangers of hunting, the illegal pet trade, and continued forest destruction.

Even though the data collected shows healthy genetic diversity among two species of lemurs, lemur populations have been greatly negatively affected by deforestation and forest fragmentation. If forest destruction is allowed to continue, the genetics of the lemurs will soon become as limited as their habitats and the possibility of extinction will become a reality. Deforestation and forest fragmentation is devastating for all species, plant and animals alike, around the world, including humans. Collecting data to see the effects of deforestation and forest fragmentation is an important step to understanding how this practice affects life. However, the usefulness of this information is limited to the exposure it gets. It is important to educate the people in the communities where deforestation and forest fragmentation is occurring. Education has to be done in a respectful manner which is culturally acceptable to those communities. The information should be relayed in a way which will highlight the communities' emotional connection to the natural habitat, the logic in adapting new, more productive farming techniques, and the real possibility of long term sustainability for both them and the nature in which they live.

In addition to addressing the smallholders for their part in deforestation and forest fragmentation in Madagascar, it is also important to work with the government to address the seriousness of the long term devastation this practice is causing. It is important to have viable solutions available to present to both smallholders and the government. This could make it easier for long term, less damaging farming practices to be adapted and established.

To improve the livelihood, sustainability, and well-being of households, agricultural practices need to be transformed (Urech et al., 2015). Permanent systems should be used which does not undermine soil fertility, will produce enough crops for the local population, and is able to coexist with the remaining forest (Urech et al., 2015). A possible solution is hydroponic farming. The need for more land could be decreased using hydroponics by growing crops in towers (Khan et al., 2018). Hydroponic farming grows plants without soil and is a more sustainable method of farming (Slavikova et al., 2018). The electricity needed for hydroponic farms could be generated from wind or solar power using a commercial battery to store excess renewable energy. With hydroponics, food can be grown more densely using a fraction of the land that traditional crops use. This would greatly reduce deforestation and fragmentation, and allows for the possibility of the forest to regrow. Hydroponic farms are scalable and can be built as large or small as needed for the population (Slavikova et al., 2018).

One advantage of hydroponic greenhouse is the equal distribution of natural light which allows different crops to grow at the same time. Other advantages of hydroponic farming is the variety of crops which can be grown in a hydroponic greenhouse, such as green leafy vegetable, flower, and rice. Additionally, hydroponic systems have minimal use of pesticides and conserves water. Hydroponic greenhouses are able to produce higher nutritional crops with less growing time using less land and water required by traditional land farming. With hydroponic greenhouse cultivation, rice is harvested four time annually compared to single harvesting in open field agriculture. The initial cost of installing hydroponic greenhouses is high (Slavikova et al., 2018). However, the costs will go down over time, and the long term benefits compared to the tavy system is invaluable.

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