Terrestrial Environment Flashcards
Biomes?
Band across the hemisphere and transition into one another. Combination of different factors largest being the climate.
Vertical stratification?
Shapes and sizes of plants largely define layering in forests. Generally contain multiple layers - all share certain characteristics. Support different biodiversity on each level. All interlinked soil gets nutrients from fallen leaves etc.
What are the usual layers in a forest?
Upper canopy Upper middle Shrub understory Ground layer of herbaceous plants Forest floor litter layer
Regional distinction?
Procession of evolution. Environments vary and so does the species.
Stability vs. Disturbance
Boomed are dynamic natural disturbances are the normal. Results in many biomes being patchy as local disturbance affects specific areas. Can vary from small like tree branch fall to large event hurricane or fire. Some need disturbance like savanna needs fire to reproduce.
Tropical forests?
Require generally hot and wet conditions - tend to be nutrient poor. Pronounced vertical stratification. Canopy often closed and less then 1% of the sunlight reaches the floor.
Recycling good and competition high.
Epiphytes is common for to lack of space. Fig trees ( strangler fig) kill other trees
Soils often poor but nutrients recycled therefore efficient. High level of disturbance
Savanna?
Enormous production - mixture of grasses and trees. Dry climactic conditions. Woody savanna and grassy savanna.
High productive and can support large herbivorous biomass. However seasonal. Patchy distribution. Migration - animals move to where the food is. Plants cannot move
wet for a couple months can support secondary consumer.
Common fires and lightning.
Insects and termites are the big herbivores in the savanna - carbon production. The dominant plant species are fire adapted. Savanna thickening currently as trees become more common in wetter conditions.
Desert?
Regions of low rainfall less than 30mm a year. Temperate is variable (hot/cold deserts) lack of cloud. Can be cold even the hot ones very substantial.
Animals evolved to fill specific roles - can take water from food.
Dry valleys in South Pole Driest place on earth.
CAM ( crasslucian acid metabolism) common. Photosynthesis that conserves water, but less efficient.
Chaparral?
Diverse and uncommon. But common in the Mediterranean region and California.
Mild rainy winters and long hot dry summers. Lots of productivity in wet season. Dense spiny evergreen shrubs dominate, cannot support large trees. Like savannas prone to fires with only some species being able to survive.
Temperate grassland?
Worldwide, dominant. Grass dominant with sporadic trees,don’t have conditions to have large trees. Large herbivores prevent them.
Moderate annual rainfall, periods or drought and fire. Can be further divided into praines and steppes. Steppes are shorter and more water resistant. Russian steppe is coast to coast.
Temperate deciduous grassland?
The UK- ecosystem dominated by trees e.g. Oaks, birch, maple etc. Trees that drop leaves in winter. Huge amount of material going back into the system. Hot summers and cold winters - moderate precipitation (750-1500) sunlight canopy penetration variable throughout the year. Understory plants can grow.
Coniferous forest?
In cold regions of the northern region. Low diversity. Cold and nutrient poor soils enable them to thrive where deciduous trees can’t survive (adapted) largest trees in the world are coniferous (Hyperion)
Tundra?
Cold, soils dominated by permafrost layer. Little water available. Precipitation 100-250 very short growing season therefore little species diversity. Small plants take advantage of small area of water but not enough for trees.
Soils?
Very critical. The quality and amount of soil are critical for determining health, size and biodiversity. Parameters such as pH can have a fundamental effect on species assemblege
Savanna drained and nutrient rich. Whereas Scotland waterlogged.
Can be further divided into litter, topsoil, subsoil, and bedrock.
Water availability?
Precipitation an indication of the climate. Affected by the soil type - water in soil/rock called ground water.
Water table- the boundary between a saturated layer and unsaturated soil above.
Low water table - plants with deep tap roots. High plants with fibrous roots.
Leaching is seeping water dissolves and transports organic matter and mineral lower in the soil.
