bi303 terrestrial dynamics

aspects of terrestrial dynamics

drivers of climate variation

major biomes

ecological variation by biome

learning objectives

• what is a biome and why are they distributed the way they are?

• what distinguishes the major terrestrial biomes

• what environmental parameters do plants and animals have to adapt to in different biomes

terrestrial biomes overview

distinct assemblages of plant + animal groups occupying a given location

based on temp and precip

biome identity determined by what

temperature and precipitation

how is primary productivity related to biomes

warm + wet = higher npp

variation in temp

solar radiation strikes tropics more directly than poles → hotter

poles are further than tropics due to earths globe shape → travels far → loses more energy

variation in precipitation

weather cells - polar, ferrel, hadley

trade winds and westerlies - curved in regards to earth’s spin, CORIOLIS effect

rain shadow where the windward side of a mountain gets rain and grows forests

lake effect snow where the wind hits the water and the lake water warmer than air rises into snowfall

elevation - loss of moisture as increased elevation

tropical rainforest

temp - high year round

precip - high year round

soil - weathered, acidic, nutrient poor

plants - shade tolerant, carnivorous, parasites

tropical seasonal forest

temp - high year round

precip - wet and dry seasons

soil - rich and less acidic than rainforest

plants - many trees are drought-deciduous (‘dead’ with drought, flourish in water)

tropical savanna

temp - high year round

precip - short wet long dry season

soil - productive but impermeable subsoil traps the water

plants - grass-dominated with hardy, drought-deciduous trees

hot desert

temp - mostly hot w high seasonal/daily variation (nights cold)

precip - very low/none

soil - low in nutrients, covered in biocrust

plants - defended against heat, uv and herbivores, cacti have spines so that herbivores cant get to the water inside

temperate grassland

temp - warm summers cold winters

precip - wetter in the summer

soil - deep and very fertile

plants - grasses and herbs, benefit from fire and grazing, fire returns nutrients to the land

deciduous forest

temp - warm summers mild/cold winters

precip - moderate

soil - thick, fertile, rich in organic matter + nutrients

plants - cold-deciduous trees, conifers

temperate shrubland/woodland

temp - warm summers, mild/cold winters

precip - dry summers, wet winters

soil - dry, compacted, low fertility

plants - many shrubs + small trees, adapted to drought and fire

temperate rainforest

temp - cool summers, mild winters

precip - high except summer

soil - infertile

plants - coniferous trees

taiga/boreal forest

temp - warm summers, mild/cold winters

precip - moderate w little evaporation

soil - acidic, organic-rich but sometimes thick and waterlogged (peat)

plants - evergreen conifers w deciduous trees, shrubs, adapted to fire

tundra

temp - cold/subzero mostly

precip - low w little evaporation

soil - thick, permafrost

plants - moss, lichen, perennial

ecological variation by biome

soil, plant mycorrhizal association, net primary productivity

evb soil

clay/sand/silt and pH (minerals)

microbial biomass involves fungi and bacteria

evb mychorrhizal association

mycorrhizal - inside the soil, based on phosphorous (AM)

ectomycorrhizal - outside the soil, based on nitrogen (EM)

evp npp

limited by carbon, temperature, water and sunlight

sequestered carbon in the soil