The dominant tree species in Bago semi- evergreen forest are Xylia xylocarpa (or X. dolabriformis) (Fabaceae) and Tectona grandis (Lamiaceae), with Lagerstoemia spp. (Lythraceae), Dipterocarpus alatus and D. turbinatus (Dipterocarpaceae) also present (Suzuki et al 2004). Bamboos are present throughout, particularly in degraded or formerly cleared areas, and include the species Bambusa polymorpha and Cephalostachyum pergracile (Poaceae).
Bago semi-evergreen forest
ပဲခူး အမြဲစိမ်းဆန်တော
Extinction Risk
NE
DD
LC
NT
VU
EN
National IUCN statusCR
CO
Climate and ecology
RealmTerrestrial
BiomeTropical And Subtropical Forests
Functional GroupTropical/subtropical dry forests and scrubs
Description
A semi-evergreen forest that formally occurred across much of the Bago Yoma. Xylia xylocarpa and Teak (Tectona grandis) are the primary species with dominance changing from south to north along a precipitation gradient (Stamp, 1924b). It is primarily deciduous, but some evergreen elements may occur. Much of the Bago Yoma range is now highly degraded with plantation teak and bamboo regrowth.
Distribution
Occurs across the majority of the Bago Yoma with approximately 18,000 km2 identified in our remote sensing analysis.
Characteristic
Native biota
Details
Abiotic environment
Mean temperature
26.1° C
Soil
light-textured and erodible (Suzuki et al., 2004)
Precipitation
950 - 2,500 mm per annum
Elevation
No data
Details
This ecosystem occurs in areas with moderately high rainfall with high seasonality, with most rainfall occurring between May and October. Mean annual rainfall varies from 1,500 mm in the north to 2,500 mm in the south, but to the driest foothills in rain shadows may receive as little as 950 mm (Kress et al., 2003). Mean temperature 26.1° C. Soils are generally light-textured and erodible, with increasing clay content with depth (Suzuki et al., 2004).
Key processes and interactions
Rainfall seasonality and seasonal water stress is a key factor that influences the distribution and species composition of seasonally dry ecosystems such as Bago semi-evergreen forest (Banda et al., 2016). The dominant tree species are drought- deciduous, enabling them to persist through prolonged water deficits in the dry season, and support rapid growth when monsoon rains fuel primary productivity. Flammability is likely to be low, except where extensive disturbance has promoted increased fire activity, particularly in areas with large tracts of bamboo regrowth.
Major threat
Major threat
The ecosystem has been extensively logged, fragmented by shifting cultivation and the development of plantations (Shimuzu et al., 2017). Only tiny patches of primary forest remain, with the vast majority of this ecosystem now occurring as highly degraded forest regrowth dominated by bamboo. Post-disturbance bamboo thicket may be a persistent steady state, with dense stands limiting dispersal and establishment of tree species typical of primary forest. They may also maintain a fire regime that limits establishment of primary forest species. The impact of shifting cultivation has been reported to be decreasing in the last decade, while logging, plantation development, urban development and water conversion (new dams) have expanded (Shimuzu et al., 2017). Poaching of wild fauna, including elephants, appears regular (Sampson et al., 2018).
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 now occurs across a relatively small distribution, and about 33.9% of the ecosystem is considered degraded since a primary state at year 1750. Ongoing degradation is clearly occurring, with 6.8% of remaining primary areas lost between 2000-2017. Projections from this dataset suggest that ongoing degradation will not occur sufficiently to meet category thresholds for D2b. However, a climate suitability simulation model suggests that environmental suitability for this ecosystem will severely reduce by 2050, with an extent and severity sufficient to meet the thresholds for Critically Endangered, with model uncertainty suggesting a plausible bound of listing between Endangered and Critically Endangered.
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
Bago semi-evergreen forest is regarded as collapsed when its mapped distribution has declined to zero, or when primary forest accounts for 0% of total forest cover, or when patches of remnant primary forest are less than 1-10 km2 in area.
Date Assessed
2019-06-20
Year published
2019
Assessed by
Nicholas Murray,Steven Platt
Reviewed by
David Keith
Contributed by
references
references
Resources
ecosytems-MM view.csv
Myanmar Translation
