Alpine cliffs and screes

မြင့်မားသော တောင်ပေါ်‌ဒေသ ကျောက်ကမ်းပါးစောက်များနှင့် ကျောက်ကျိုးပဲ့ မျက်နှာပြင်များ

Extinction Risk

NE
DD
National IUCN statusLC
NT
VU
EN
CR
CO

Climate and ecology

Realm

Terrestrial

Biome

Polar/Alpine

Functional Group

Polar/alpine rocky outcrops

Description

Alpine cliffs and screes are bare, icy, rocky areas amongst permanent snow fields. Vascular vegetation is low and sparse or absent, and the most common plants are crustose lichens and bryophytes (Keith et al., in review).

Distribution

This ecosystem occurs on the steep upper slopes of the highest mountain peaks amongst glaciers and permanent snowfields, of northern Myanmar and adjacent countries.

Characteristic

Native biota

Details

The extreme conditions limit the expression of life in these ecosystems, which are characterised by low species diversity, low biomass and low productivity. Lichens, bryophytes and cyanobacteria are the primary producers that inhabit rock surfaces although non-woody vascular plants may be found in crevices where shallow soil accumulates. Other microbes and a small number of insect species likely perform functions as decomposers and detritivores. No information was found on the identity of species that characterise these assemblages in Myanmar. Tussocks of Diapensia himalaica (Diapensiaceae), Androsace, and primulas, such as the endemic Primula vaginata subsp. eucyclia, and P. agleniana var. thearosa (Primulaceae), and woolly plants such as Saussurea (Asteraceae), as well as cushion- forming plants like Arenaria polytrichoides (Caryophyllaceae) can be found at the highest elevations, growing in scree just below the snow line.

Abiotic environment

Mean temperature

No data

Soil

Little to no soil

Precipitation

No data

Elevation

> 4,500 m above sea level

Details

This ecosystem is found at very high altitudes (approximately >4,500 m above sea level) and is characterised by extremely steep slopes (50-90°), extreme cold, exposure to high winds and periodic desiccation. Soils are essentially absent due to steep slopes or else skeletal and confined to crevices amongst rock.

Key processes and interactions

Extremely steep slopes promote erosion, prevent soil development and facilitate periodic mass movement through landslides and avalanches which remove living biomass. High altitudes and steep slopes, together with very low temperatures exacerbated by wind chill associated with periodically high velocity winds. Frosts and ice promote weathering through frost heave and limit the inhabitability of rock surfaces. Mutualisms within lichens are important but otherwise biotic interactions are weak.

Major threat

Major threat

The most plausible threat is global warming, which may elevate temperatures, alter frequencies of snow cover and desiccation regimes. The magnitude of these changes is uncertain, as is the response of the sparse biota, but is likely to be negligible. If desiccation is significant, however, it could have an impact on the cover of bryophytes and lichen.

Instruction: The visualization shows threats that are present within each ecosystem. According to IUCN, direct threats are the proximate human activities or processes that have impacted, are impacting, or may impact the the status of the taxon being assessed. Click of the highlighted icons to see details each threat category.

Ecosystem Assessment

Assessment Summary

This ecosystem is restricted to small areas in northern Myanmar, but inferred threatening processes are unlikely to cause continuing declines of a non-negligible magnitude in extent. Least Concern.

Instruction: Click on the chart to view the detailed assessment result for each RLE risk criteria. Risk is defined as the probability of an adverse outcome over a specified time-frame. Here, the adverse outcome is the endpoint of ecosystem decline, which the RLE terms ecosystem collapse.

Ecosystem collapse definition

The system reaches a collapsed state when exposed rock is covered permanently by snow or by vascular vegetation.

Date Assessed

2019-11-26

Year published

2019

Assessed by

David Keith,Nicholas Murray

Reviewed by

Hedley Grantham

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