Ecosystems- productivity
High productivity ecosystems:
Temperate deciduous forest
Productivity- high NPP, 1.2kg/m2/year, result of high summer temps and large amounts of daylight. Large amount of biomass as a result of woody material
Vegetation- varies with soil type- acidic→ birch and rowan trees, alkaline→ box and maple, elm common on clay, willow on gleyed soils. Oak often dominant due to tolerance of wider ph range. More ground vegetation beneath oak trees, as small leaves allow more light to ground
Climate- mild/wet up to 1500mm per year, more in winter often from depressions. More precipitation than evapotranspiration. Temps above freezing in winter. Average temperatures 15-20 degrees
Soils- fertile brown earths, with a mildly acidic mull humus. Wide range of flora and fauna in litter layer, soil mixing encouraged by earthworms. Blurred soil horizons due to worms
Nutrient cycle- fast rates of leaching balanced by fast rates of weathering. Many nutrients in soil as a result of slow winter growth and low density of vegetation
Animals- adaptations occur in the winter because of low temperatures. Many animals either migrate or hibernate in the winter
Human interference- few natural areas are left, and many areas have been cleared for agriculture, or recreation
Tropical rainforest
Productivity- 100-3500g/m2/year, high due to the annual temperatures and precipitation values that support rapid plant growth
Vegetation- characterised by vertical layering of vegetation and the formation of disitinct habitats for animals. Tall trees and a layer of sparse plants on the forest floor
Climate- annual rainfall ranges from 250cm to more than 450cm with considerable seasonal variation. Average temperatures range from 20-34 degreees, month to month temperatures relatively consistent
Soils- high levels of rainfall mean that the nutrients are stored above ground, and the deeper soil is very infertile and acidic. Commonly latosol, which can be several meters thick
Nutrient cycle- lack of temperature seasonality leads to year round plant growth, alongside the more constant daily sunlight. The high rainfall quickly leaches nutrients from the soil
Animals- many different species have adapted to the conditions of the rainforest,40-75% of all species globally. Includes sloths, frogs, orangutans and macaws
Human interference- significantly impacts tropical rainforests, primarily through deforestation for various different purposes such as agriculture, logging and resource extraction
Low productivity ecosystems
Temperate coniferous (boreal) forest
Productivity- low, NPP= 0.8kg/m2/year. High biomass from the woody material
Vegetation- trees 20-30m high, mainly pine, larch and spruce. Evergreen to allow photosynthesis all year. Needle leaves reduce evapotranspiration, conical shape removes snow easily
Climate- either cool temperate or cold continental. Small amounts of rainfall (below 500mm per year). Summer frosts, much winter snowfall, precipitation above evapotranspiration. Reduced growing season, but 16-20 hours of sunlight in summer increases photosynthesis
Soils- normally podsols. Leaching is a result of snowmelt. Humus is acidic (ph 4.5-5.5). Iron pans may form. Few earthworms lead to distinct horizons. A thick litter layer
Nutrient cycle- controlled by the low temperatures which limit rates of weathering in transfer, resulting in many nutrients in the litter
Animals- sparse as little available food
Human interference- in the uk many are planted and used for forestry
Desert:
Productivity- have very low productivity (0-250g/m2/year), low amount of biomass due to harsh growing conditions
Vegetation- perennial plants struggle to survive due to low humidity, scarce precipitation and high temperatures
Climate- variable based on type of desert, extremely arid deserts have <70mm/year, semi-arid has 150-300mm/year. Low relative humidity and high potential evapotranspiration. High solar irradiance, often with no clouds
Soils- aridisols, high ph with a lack of organic matter, including humus. Accumulation of salts because of low penetration of precipitation and high evaporation. Due to limited cover of vegetation, dry clay and silt particles are easily eroded from the soil surface
Nutrient cycle- very slow, growth of plants limited, very small biomass and litter stores, loss through runoff
Animals- small mammals such as mice and rats, large mammals such as bobcat and coyote
Human interference- can cause desertification, in areas which are not typically desert conditions. Can cause wildlife to be at risk of dying out due to threats such as urban sprawl, cattle grazing, mining, dam building and off road driving