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Fire events in Tripa Fire events in Tripa
Although the burning of peat is forbidden by Indonesian law, more than 458 fire hotspots have been detected by satellite in Tripa during the last 10 years, the vast majority being located within palm oil concessions.
13 Sep 2011 - by Riccardo Pravettoni, UNEP/GRID-Arendal
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Abatement costs for transition from undisturbed forest to other land uses Abatement costs for transition from undisturbed forest to other land uses
Opportunity costs for the transition from forest to other land uses between 1994-2009 in Tripa and 1990-2009 in Batang Toru are shown. For the transition to the most profitable land-use a price of slightly more than USD 10 per tCO2 would have been sufficient to offset opportunity costs in Batang Toru. For Tripa this value is lower because of the below ground carbon stocks in the peatlands.
13 Sep 2011 - by Riccardo Pravettoni, UNEP/GRID-Arendal
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Conversion of forests to different land uses Conversion of forests to different land uses
Using satellite images, land use changes were determined at Batang Toru (2001-2009) and Tripa (2001-2009) to calculate overall CO2 emissions. Deforestation in both areas led to different land use transitions, with the predominant land use in Batang Toru after deforestation being disturbed forest and in Tripa, oil palm plantations.
13 Sep 2011 - by Riccardo Pravettoni, UNEP/GRID-Arendal
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Conversion from primary forest to other land uses, 1985-2007 Conversion from primary forest to other land uses, 1985-2007
The main driver for forest loss on peat areas in the Leuser Ecosystem was oil palm development between 1985 and 2007, while for forest on non-peatlands other land uses than oil palm contributed more to land use changes.
13 Sep 2011 - by Riccardo Pravettoni, UNEP/GRID-Arendal
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Below-ground carbon stocks Below-ground carbon stocks
The three coastal peat swamps of Tripa, Kluet and Singkil together represent the most important habitat for Sumatran oran-gutan populations in terms of density (van Schaik et al. 1995). When considering that the depth of the peat exceeds more than five metres in many parts of Aceh’s peatlands, these coastal peat swamp forests represent by far the largest carbon stocks per unit area for the areas where Sumatran orangutans occur (Wahyunto et al. ...
13 Sep 2011 - by Riccardo Pravettoni, UNEP/GRID-Arendal
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Carbon storage in terrestrial ecosystems vs. great ape distribution Carbon storage in terrestrial ecosystems vs. great ape distribution
All great ape species predominantly live in tropical rainforests, which are among the most carbon-rich areas in the world. This overlap between the areas where great apes occur and carbon indicates that more potential synergies between great apes and carbon conservation exist.
13 Sep 2011 - by Riccardo Pravettoni, UNEP/GRID-Arendal
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Land cover change in Batang Toru Land cover change in Batang Toru
Migration from the island of Nias to the West Batang Toru forests over the last two decades has been largely spontaneous. These settlers have opened up primary forests for agriculture and hunt many species of local wildlife, including orangutans. Currently at least eight Nias communities have been established inside the protected forest in the Batang Toru area, leading to the loss of more than 2,200 ha of orangutan forest habitat in specifically ...
13 Sep 2011 - by Riccardo Pravettoni, UNEP/GRID-Arendal
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Ecosystem services value for the Leuser Ecosystem Ecosystem services value for the Leuser Ecosystem
Values for the various non-carbon ecosystem services (water, regulation of floods and landslides, fisheries, prevention and limitation of fires, agriculture, tourism, and non-timber forest products (NTFP) and biodiversity) were calculated with a discount rate of 4% over a 30-year period. Total value for ecosystem services beyond climate regulation being USD 3,735/ha.
13 Sep 2011 - by Riccardo Pravettoni, UNEP/GRID-Arendal
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Timber concessions Timber concessions
Some timber concessions overlap orangutan habitat in a number of key locations. If left to recover after logging, orangutans will gradually return to former concessions. But if the land is converted to monoculture plantations this will no longer be possible.
13 Sep 2011 - by Riccardo Pravettoni, UNEP/GRID-Arendal
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Distribution of benefits under different land use scenarios in the Leuser Ecosystem Distribution of benefits under different land use scenarios in the Leuser Ecosystem
Net present value (NPV) is in millions of USD over a 30-year period (2000-2030) at a 4% discount rate. The NPV for local communities under a deforestation scenario would be 3,132 million USD and under a conservation scenario 5,341 million USD. The analysis shows that the local community would benefit most from a scenario under which the forest is conserved, negative effects on ecosystem services are avoided and payments for ecosystem services ar...
13 Sep 2011 - by Riccardo Pravettoni, UNEP/GRID-Arendal
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Population growth in North Sumatra and Aceh 1920-2008 Population growth in North Sumatra and Aceh 1920-2008
Overall population growth in the region has been very rapid during the past nine decades. In 1920, the human populations of Aceh and North Sumatra provinces were 736,348 and 1,961,678, respectively (Volkstelling 1922). By 2008, these had risen dramatically to 4,293,915 and 13,042,317 (BPS 2010a).
13 Sep 2011 - by Riccardo Pravettoni, UNEP/GRID-Arendal
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Forest status Forest status
Most Sumatran orangutan habitat is protected by Indonesian law. The government has created a very comprehensive system of functional forest categories, and institutions responsible for managing its forests. Some areas remain highly threatened, however, including the Batang Toru Forest (production forest), and the Tripa Swamp Forest (not part of the formal forest estate).
01 Mar 2011 - by Riccardo Pravettoni, UNEP/GRID-Arendal
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Plantation concessions Plantation concessions
Oil palm plantations depend on the microclimate conditions generated by nearby forests, and the rivers emanating from orangutan habitat. Not all plantations concessions on the map have been cleared and planted yet. The majority of concessions are oil palm, but the map also contains rubber and other plantation crops. The establishment of many of these plantations has resulted in significant losses in orangutan habitat, since they have been created...
13 Sep 2011 - by Riccardo Pravettoni, UNEP/GRID-Arendal
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Sites Sites
Sumatran orangutan habitat is restricted to the westernmost tip of Indonesia. Boxes indicate the case study areas Tripa and Batang Toru. The case of Sumatran orangutan serves as a useful example to illustrate how the fate of one of our nearest relatives is closely tied to ours.
13 Sep 2011 - by Riccardo Pravettoni, UNEP/GRID-Arendal
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Hydrogeology Hydrogeology
Most of the Sumatran orangutan's forests inland play a key role in ensuring downstream freshwater supplies, since the non-alluvial inland areas of the region tend to have very little or no underlying groundwater resources.
13 Sep 2011 - by Riccardo Pravettoni, UNEP/GRID-Arendal
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Forest loss from 1985-2007 for Sumatra Forest loss from 1985-2007 for Sumatra
If only the most important orangutan habitat is examined – i.e. forest below 1,000 m – for the 1985-2007 period, the rate of loss was even higher, at 28% and 49% for Aceh and North Sumatra respectively. When only the most species-rich forests (below 500 m) are considered, forest loss between 1985 and 2007 was 36% for Aceh and 61% for North Sumatra. For the carbon-rich peat swamp forests the loss was 33% for Aceh and 78% for North Sumatra.
13 Sep 2011 - by Riccardo Pravettoni, UNEP/GRID-Arendal
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Above-ground carbon-stock density changes Above-ground carbon-stock density changes
In Batang Toru, land use changes and deforestation led to an overall loss of around 10 tonnes of carbon per hectare between 1994 and 2009. Due to its exploitation for the cultivation of oil palm, the peat area of Tripa had to face a much more important decrease of 66 tonnes of carbon per hectare in the time period 1990-2009. In terms of CO2 emissions, it corresponds to an overall emission per year of 634,903 tCO2.
13 Sep 2011 - by Riccardo Pravettoni, UNEP/GRID-Arendal
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Hunting of orangutans Hunting of orangutans
Orangutans are also still regularly killed or captured. This occurs for three main reasons: first, even today some people still hunt orangutans for food, most notably in the non-Muslim parts of North Sumatra. Second, when orangutans enter farms or plantations at the for-est edge, for example to feed on fruit trees or other crops, they are often shot or otherwise killed, and any surviving infant eventually ends up in trade or as someone’s illegal ...
13 Sep 2011 - by Riccardo Pravettoni, UNEP/GRID-Arendal
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Change in forest cover, 1985-2007 Change in forest cover, 1985-2007
Between 1985 and 2007, 49.3% of all forests on the island were lost. In the provinces of Aceh and North Sumatra the figures were 22.7% and 43.4%, respectively. Most forest loss has occurred in the lowlands, the very areas where orangutan density is highest.
13 Sep 2011 - by Riccardo Pravettoni, UNEP/GRID-Arendal
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Multinational networks to exploit natural resources Multinational networks to exploit natural resources
A generalized diagram of how multinational networks exploit natural resources by developing numerous temporary subsidiaries and use corruption and security firms to ensure rapid exploitation and maximum profits. Arms trading has been reported from the Democratic Republic of the Congo, while the bribes and “security firms” also play a major role in Indonesia. This graphic is republished from "The last stand of the Orangutan" Rapid Response Assessm...
08 Mar 2011 - by Hugo Ahlenius
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