Ecosystem Comparisons: Desert vs Temperate Forest

Desert

• Climate: Water is a limiting factor, with less than 250mm of rain per year. Temperatures can be very high or very low.
• Soils: Very slow decomposition rate, soils are very thin, and nutrient poor.
• Vegetation: Lowest NPP, drought-resistant plants, slow growth, spines or waxy coatings.
• Animal Adaptations: Very low biodiversity, short food chains, reptiles dominant, mostly nocturnal mammals, absorb water from food.
• Issues: Global warming increases droughts, drying up water holes, increasing wildfires, and replacing slow-growing trees and shrubs with fast-growing grasses.

Temperate Forest

• Climate: Four distinct seasons, high rainfall, freezing winter.
• Soils: Perfect conditions, not too wet or dry, deep, nutrient-rich, and lots of organic matter.
• Vegetation: Second highest NPP, limited by leaf loss during winter, deciduous trees dominate.
• Animal Adaptations: Rich diversity, animals adapted to changing seasons. Some animals migrate or hibernate in the winter.
• Issues: Most of the human race lives within these regions; deforestation is used for urbanization and the area is the world's primary timber source, Many larger predators have been (or nearly wiped out).

Tropical Rainforest

• Climate: High temperatures and high rainfall all year; a relative “dryer” period around August.
• Soils: Soil is very thin with poor nutrients. Nutrients are used very quickly and intense rain washes them away.
• Vegetation: Highest NPP, layered ecosystem, plants have shallow roots due to thin soils. Sunlight is a limiting factor.
• Animal Adaptations: Highly diverse ecosystem, but many are specialists living in different canopy levels. Camouflage is common.
• Issues: Some forest is cut for timber, but mostly clear-cut to convert land for agricultural use (palm oil or livestock/cattle).

Tundra

• Climate: Cold with low precipitation, long dark winters, and strong winds year round.
• Soils: Subsoil permanently frozen. Soils above permafrost are waterlogged and too shallow for tree roots.
• Vegetation: Cold restricts vegetation; growing season is less than 3 months. Very low NPP, mostly mosses and lichens.
• Animal Adaptations: Small food chains, low biodiversity with few predators. Thick insulated coats and small ears for insulation.
• Issues: Takes decades to recover after disturbance, Mining and oil extraction destroy ecosystems, climate change melting permafrost.

Tropical Grassland

• Climate: High temperatures all year, distinct wet and dry seasons. Fire is important to the ecosystem.
• Soils: Very low in nutrients and organic matter. Weathering during the rainy season.
• Vegetation: Relatively high NPP compared to biomass, very limited by water during dry season grasses dominate. Few trees, some with thorns for protection.
• Animal Adaptations: Greatest number of grazing animals adapted to short rainy seasons (migrate - reproduce during rainy season).
• Issues: Legal poaching; about 10% has been converted for agriculture or urban development. Desertification is also a significant threat associated with agriculture in this biome.

Temperate Grassland

• Climate: High temperatures all year, distinct wet and dry seasons. Fire is important.
• Soils: Grasses die back in the winter, decompose, and form a mat with high nutrient levels.
• Vegetation: Flat areas dominated by grasses; non-woody plants. Due to winter and low rainfall, productivity overall is very low.
• Animal Adaptations: Surprising very low in diversity. Mostly larger herbivores (bison) and smaller, burrowing mammals.
• Issues: 47% has been turned into agricultural land because of the rich soils. Overgrazing and plowing are the greatest threats, but years of wildlife eradication also threaten the ecosystem.