altitude
alpine refers to areas above the tree line (climatic limit of tree growth - where the mean temperature of the warmest month is less than 11 degrees C) and below the snow line (zone of permanent snow cover)
latitude + altitude
the tree line decreases approximately 110 m in altitude for each additional 1 degree of latitude from the equator
New Guinea highlands (6 degrees S) has a treeline of 3700m VS
NSW (36 degrees S) has a tree line at 1850m
size
the largest and highest area of mountain lands occur in the himalaya-tibet region (reaching 8848m in altitude and covering an area of 600 000km2) the alpine zone extends from 3200m - 4200m
continuity
the largest contiguous area of alpine extends along the Andes (7200km long) from Peru (treeline = 4300m) to Chile (treeline = 1600m)
term = islands in the sky which makes them vulnerable
significant areas of alpine to namedrop
Europe: The Alps, Pyrenees Asia: Caucasus, Urals Highlands of New Guinea Southern Alps of NZ East Africa Highlands
spatial patterns and dimensions of Australia
size: sub alpine and alpine areas occupy 11 200km2 of Aus. True alpine areas occupy only 250km2 (0.003% of Aus)
latitude/altitude: Australian alps 36 degrees S, 1850m
spatial patterns and dimensions of Kosciusko National Park
Location: southern end of Great Dividing range in the Aus Alps, 350km SW of Sydney.
Latitude: 35-37S, 145-149E
Size: covers 100km2 (40% of Aus alpine ecosystem)
Continuity: it is the largest continuous zone of alpine vegetation in Australia
Has Australia’s highest mountain, Mt Kosciusko (2228m tall)
Atmosphere
- temperature decreases by 6.5C per km increase in altitude
- alpine area has a continuous snow cover for >4 months of the year (June - September)
- 10 frost free days per year on Mt K
- the treeline has risen 40m
Hydrosphere
- orographic rainfall: produced when moist air is lifted as it moves over a mountain range –> resulting in a dense and moist Western fall and sparse dry East Planes
- weak glaciation has produced features (Blue Lake) with long periods of erosion leaving exposed granite boulder fields
- peri glacial processes of freezing and thawing results in weathered rock and porous, skeletal soil which can be easily eroded (nutrients loss)
Lithosphere
- soil development is slow
- dominant soil type = alpine humus soils (shallow skeletal soil) which are low in nutrients due to slow rates of decomposition
- nutrients transported out of the soil profile by water (leaching) increasing acidity
- low temperatures, leaching, frosts, strong winds and slow regrowth makes soil vulnerable
- exposed soil open to agents of erosion due to slow plant growth
Process to form plateau
- uplift over 40 years
- glaciation
- plateau is dissected due oto erosion, forming islands in the sky, small, fragmented ecosystems
Wetlands
- bogs and fens allow for slow release of snow melt to streams and rivers during summer
- maintain water during winter with sphagnum moss, storing 20x their weight in water
- permanently wet, providing unique habitats for threatened terrestrial and semi-aquatic species such as the southern corroboree frog
Plant community and adapting
- growing season is too short to sustain trees
- short life cycle of rapid growth
- flowering and seed production (surviving winter as a seed)
Types
Tall alpine herbfield: covers 65% of alpine area. Found on well drained slopes, most resilient
Other species: snow grass, silver snow daisy, mountain celery, billy buttons
Windswept feldmark: grows in the most severe conditions on ridges with little soil
Rock heath: warmth and wind shelter of boulders. WOody shrubs with a slow growth rate.
Bog: sphagnum moss and candle heath
Ecological succession
- 204 species of native flowering plants (21 endemic)
- low energy
- nutrient limitations of soil = slow growth = high vulnerability
- increasing frequency of natural stresses (bushfires)
Animals
- digging mammals improve soil heath by turnover and mixing organic matter
- MPP is endemic to alpine and subalpine regions of SE australia
- estimated 685 in KNP. 2 of the best habitat sites occur within the leased ski resort areas of mt blue cow (perisher) and charlotte pass ski resort (40% of population occurs here)
Adaptations
- growing on boulders (warmth)
- dorman seeds
- to battle intense sunshine, leaves may be reflective, have small surface area
- pineapple grass is fire retardant
- sphagnum moss (20x weight in water)
- protection in subnivean space
- torpor / aestivation (bogong moths MPP)
Natural stresses
Frost, wind, drought, weather extremes, fire
Drought - el nino
Reduced depth and longevity of snow pack
- lack of habitat and spring runoff from bogs and fens
- lack of available subnivean space for alpine fauna
- earlier invasion of subalpine and montane predator species
Bushfire
2003
- alpine vegetation was burnt as high to very high severity
- most serious impact = sphagnum moss (growth rate = 3.5cm per 100 years)
- fire burnt through 20% of MPP habitat in southern end and >80% of habitat in Northern KNP
2020 (black summer)
- 1/3 of KNP was burnt
- horses congregate on unbrunt patches of vegetation, increasing erosion
- reduced frog population from 700 000 to 20 000 since the 80s)
- destroyed vital food sources for MPP including Mountain Plum Pine
Rate of change: Natural
Bushfire (2003 + 2020) - 58% of vegetation burnt - catastrophic cos it happened twice in a period shorter than 20 years.
Drought (2002 El Nino) - 990mm vs 1400mm average
Severe weather - 149 lightning strikes ignited a fire that burnt for 60 days
Rate of change: human
introduced species (brumbies) - 6150 wild horses in KNP (2014) –> now there are 20 000
tourism: KNP - 3 million annual visitors
Climate change (snow cover) - 30% decline in snow cover since 1954, highest annual snow depth decrease of 35.8cm since 1954.
Human impacts
Introduced species (orange hawkweed and wild horses) Tourism (ski industry and summer tourism) Climate change (reduced snow cover, vertical succession)
Grazing
- grazing affects the soil and changes the composition of plant species
- grazing started in the alpine regions of NSW and VIC in 1820
- grazing for > 100 years, 800 000 ha of soil lost
- only 60cm of topsoil remained when grazing was banned in 1958
- 60% of the alpine area was damaged by trampling of hard hoofed cattle and horses
