Deforestation and peat bog destruction explained
Ecology • Biodiversity and the effect of human interaction on ecosystems
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Definition and causes of deforestation
Deforestation means the permanent removal of trees from an area for a different land use, commonly farming, pasture, urban development or timber extraction. Large-scale causes include expansion of cattle ranching, commercial arable farming, plantation crops for food and biofuel, and logging for timber and fuel. Small-scale local wood collection has a minor effect compared with industrial clearing by large companies in biodiverse regions . Limiting factors on deforestation rates include land suitability, soil fertility, infrastructure for transporting crops and timber, and national or international policies that protect forests or encourage conversion to agriculture.
Effect of deforestation on biodiversity
Tree removal causes habitat loss and fragmentation, which reduces the number of species able to survive in the area. Tropical rainforests contain very high species richness; large-scale clearance causes local extinctions and the permanent loss of species that exist only in those habitats. High biodiversity normally supports ecosystem stability; its loss increases vulnerability to further environmental change . Species loss can be rapid where specialised niches disappear. Loss of keystone and endemic species produces cascading effects through food webs. Recolonisation of cleared land is often slow or prevented by changes in soil, microclimate and seed sources.
Deforestation and the carbon cycle
Trees store carbon in biomass through photosynthesis, acting as carbon sinks while they live. Removal of trees reduces the size of that sink and increases atmospheric carbon dioxide, particularly when trees are burned or left to rot after felling. Increased atmospheric carbon dioxide strengthens the greenhouse effect and contributes to global warming . Large-scale clearance therefore has both immediate carbon release (combustion and decomposition) and long-term reduction in carbon uptake, amplifying human-driven increases in greenhouse gas concentrations.
Water cycle, soil and landscape effects
Trees contribute to transpiration, which returns water vapour to the atmosphere and helps maintain local rainfall patterns. Removal of trees reduces transpiration, producing drier local climates and lower soil moisture. Reduced root networks increase soil erosion, nutrient loss and the risk of desertification or landslides in steep terrain . Loss of vegetative cover causes greater surface runoff during heavy rain, increasing flood risk downstream and degrading freshwater habitats.
Peat bog formation and destruction
Peat bogs develop where waterlogged, acidic, nutrient-poor conditions slow plant growth and decomposition. Partial decay of plant material accumulates as peat over long timescales, forming a significant long-term carbon store. Peat forms more rapidly than deep fossil fuels, but still at rates that make it effectively non-renewable on human timescales in many climates . Destruction occurs by drainage, agricultural conversion, peat extraction for fuel or horticulture, and by burning. Drainage and extraction expose peat to oxygen, increasing decomposition and releasing large amounts of carbon dioxide. Burning peat releases stored carbon directly to the atmosphere. Peatland loss therefore converts an effective carbon sink into a carbon source and reduces specialised peatland biodiversity .
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