Ecosystems and applications Flashcards
Desert climate and location
Very low ppt and most frequently occur in combination with high temps - rain in cool months and drought in hot months -> rapid plant life cycles
Almost entirely outside tropical zone
Seasonal temp changes with very cold winters
Productivity of deserts
Very low e.g. red dunes in Namibian desert entirely barren
Most extreme are inhospitable to almost all life
Physiological adaptations for extreme desert environments
Dromedary camel has hump for fat storage, can drink 200L water in 3 mins and can deal with dust storms
Other adaptations for extreme desert environments
Nomadism - letter-winged kite
Nocturnal - stone curlew with big eyes
Good dispersal ability - sand-grouse
Locally migratory - springbok
Heat dissipating - cape hare has large ears
Behavioural adaptation e.g. leopard tortoise hibernates, birds perform gular panting
Kangaroo
Fats and energy-efficient method of travel - spring loaded legs - to cover large distances in search or food and water.
Hydrogen by-product of fermentation converted to acetate -> more energy
Saguaro cactus USA
Very slow growing - 10 years 1.5 inches. Very shallow but widespread root system (may have tap roots)
Grasslands climate and location
e.g. Mid-West planes of USA
Outside tropical zone,monthly av temps change over the year - seasons
Temperate grasslands received rain each month, savannahs experience annual droughts
Rainy when hot, less rainy when cool
Very thin soil or high grazing pressure
Also persist above the tree line in European mountains
Grassland species and adaptations
Species that grow from close to, or below ground level to cope with grazing
Granivores - mobile e.g. quelea - multiple generations per year
Herbivores - overland migrants and synchronise birthing (saturated food source for predates), herding e.g. Wildebeest, Africa - large bodied
Herd-forming common to detect predators
Insects - camouflage
Ratite birds - large bodies, flightless vegetarians e.g. Emu. Cant move long distances so has a large gut
Savannah climate and location
Seasons marked by rainy and dry seasons
Most common in Africa
Sub/tropical grasslands with scattered trees and shrubs - not continuous
Savannah diversity
Rich diversity with large numbers of large grazers and browsers in savannahs attract a wide range of large predators and associated scavengers
Savannah adaptations (species)
Umbrella thorn - wide ranging deep and tap roots, Must be spacing due to roots. Leaves pre-adapted to heat and water stress - thorns to minimise herbivory
Bulk grazers e.g. zebra, eat almost any grasses
Selective grazers e.g. topi eat more nutritious species
Pampas grass evergreen and up to 3m tall
African elephant is an ecosystem engineer - keeping savannah open
Dung beetles and terminates nutrient cycle
Fires in savannahs
Natural and artificial
Kills young sapling trees but not grasses. Some plant seed need during to inhibit dormancy e.g. Fynbos species
Tropical evergreen forests
Extremely rich in species
Equatorial regions, total rainfall iver 250cm annually
Rainfall lower in leeward side of a mountain range than on windward side
No distinct seasons
Constant solar radiation - leave are thick and waxy
Soil is poor and thin due to high productivity - nutrients in vegetation
Tropical deciduous forests
Hot lowlands near to the equator
Relative to thorn forests
Has a long summer rainy season
Hot and dry winters = trees lose their leaves to retain nutrients
Hot and wet in summer
Species richness moderate for plants and higher other
Best soils
Temperate deciduous forest
Change with season
ppt even all year round - deciduous trees lose leaves during winter
Many animals permanent residents - hibernate, some migrate to escape cold winter
Eastern tree species poor due to glaciations and the way the mountains align
Boreal and temperate evergreen forests
Concentrated in circumpolar belts across N hemisphere and on some mountain ranges
Found below arctic tundra and at elevations below alpine tundra on temperate-zone mountains.
Long, cold winters
Short and warm winters (evergreen)
N hemisphere forests = coniferous evergreen gymnosperms
S hemisphere = southern beeches, some evergreen
Earth’s tallest trees - slow growth due to inability to photosynthesise all year, so start photosynthesising at lower temps
Pyramidal tree shape to shed heavy snow
Needle-shaped leaves with waxy coverings as physiological drought limits water loss in dry conditions
NPP low due to low temps, short growing seasons and low nutrients (slow decamp)
Tundra
High latitudes and elevation
In arctic, permanently frozen soil (permafrost) underlies tundra vegetation. Plants grow only during short summers, when the first few cm of permafrost melt. Plants shorter to be protected by snow
Photosynthesise at low temps and reproduce by budding division due to short breeding season (
What factors influence the changing of the earth?
Deforestation, drying up of lakes, species loss => species loss
Greenhouse effect
How does the greenhouse effect work?
Even receipt of short waves and uneven re-mission of long-wave radiation from the earth’s surface. Radiative forcing gases - water vapour, CO2, CH4
Ocean thermohaline circulation
Like a conveyer belt, driven by the localised formation of deep water and salinity e.g. gulf stream - north atlantic drift
Water from ocean surface evaporates, more saline, cools and reaches north, denser and sinks back south
Other natural phenomena modifying atmosphere
Fires and volcanic activity produce smoke and dust particles impacting short wave and outgoing long-wave radiation which alter energy balance
e.g. Miocene sediments in Greece - white/dark bands
How has the earth’s climate changed over time and why?
Fluctuations due to gravitational effects of other planets.
Milankovitch cycles and sun spot cycles
Solar energy not uniform around globe
Eccentricity of the earths orbit
Elliptical/almost circular
Obliquity
Earth’s axis tilt
Precession of periphelion
Equinoxes
Human perturbation of the carbon cycle
Fossil fuel emissions and land clearing - CO2 concs now over 400ppm (320 in 1965). Fluctuations in carbon level over the year due to photosynthesis
Most likely to build up => catastrophic change
Increase in pp of CO2 in atmosphere, carboxylation favoured over oxygenation in rubrics, plants do not need to work as hard, so only slightly more CO2 taken in than in lower pps
What is conservation biology?
A multi-disciplinary science heavily dependent on ecology
Aims to manage and restore biodiversity for economic, ethical and cultural/aesthetic reasins
Species response to climate change
Ecological niche models used to stimulate new colonist under climate change and changing ranges under climate change
Useful to stimulate new sites for translocations and to predict population changes
Assessing species richness and diversity
Briefly introduce some diversity measure: alpha, beta and gamma diversity and species-area relationships
Useful for defining key biodiversity areas for protection, estimating species richness of unexplored regions
Protected area priorities
Use ecological studies to inform optimal reserve sites, layouts and connectivity. Minimum areas and advise on management as well as habitat recreation. Plan for future changes in biodiversity across sites due to climate change, using niche-models
Understanding invasive alien speces
Study invasive species to assess their invasion potential, model potential control mechanisms and likely success, to understand ecology and spread and identify impacts on native species
Modelling population changes
Use mathematical models to simulate realistic range changes in species, understand the most effective times to control problem species or the most effective strategy to introduce desirable species.
Models can help us understand inexplicable pop changes, food web impacts and minimum pop sizes for effective conservation.
