Fig 1.
Number of wild orangutans reported captured for translocations: a) in Kalimantan between 2005 and 2022, and b) in Sumatra between 2012 and 2022.
No data were available on wild orangutans captured for translocations in Sumatra between 2005 and 2011, hence these years are excluded. Data were collected from published and unpublished sources including newspaper reports, orangutan rescue center news blogs, annual reports, charity commission reports, and social media posts. Any potentially duplicate records were excluded so each capture is only counted once.
Table 1.
Reported reasons for capture of wild orangutans for translocation in Kalimantan and Sumatra, 2005–2022. Information on reason for capture was available for 743 of the total 988 captures. The other 245 captures (26% of 988) are excluded from the table, as reason for capture was unknown. The percentages in the table are of the 743 captures for which relevant data were available. We recorded the primary, proximate reason the animal was captured, namely why someone was alerted to the presence of an orangutan or why they asked for it to be translocated. The underlying reasons for an orangutan’s presence in any particular location can be due to multiple factors such as availability of foods, intraspecific interactions, forest fires, and anthropogenic habitat changes, but lack of available data precludes a comprehensive analysis of these additional drivers.
Fig 2.
Percentage intact tropical moist forest from 2000 to 2020 around orangutan capture sites.
Percentage annual intact tropical moist forest cover (black dots) between 2000 and 2020 was derived from Vancutsem et al. [57]. Annual tropical moist forest layer (at 30 m) and calculated within a 5-km buffer around the capture location (n = 104) in comparison to cover in 2000. Red dots indicate the years in which wild orangutan captures for translocation took place. Grey shading indicates years where capture data is available. Absence of data does not indicate absence of translocation. The blue line is the median percentage forest cover across all capture points (GNSS coordinates). Land cover in the circles represents an example configuration at a location with percentage forest cover in 2020 at the median forest cover. Intact and degraded tropical moist forest and regrowth were combined into a single forest class (green). Remaining areas are either not forested (yellow) or water (blue). Source for forest cover: EC JRC.
Fig 3.
Forest change in area surrounding orangutan capture for translocation site 1.
A breeding population of healthy Sumatran orangutans was using a smallholder oil palm and rubber plantation for several years; at the request of the owner to remove seven orangutans, an adult male and a juvenile male were captured and translocated, while an adult female was left on site after unsuccessful capture attempts. Year of capture (2014) is indicated with thick black bordered circle. Intact tropical moist forest, degraded tropical moist forest, and regrowth are combined into a single forest class (green). The map inset at the bottom is the location of the specific capture site and buffer (yellow) along with remaining locations where 97 other orangutans were captured for translocation (black). Basemap: Google Earth Engine. Forest map: EC JRC. Protected areas (purple): UNEP-WCMC and IUCN [60].
Fig 4.
Forest change in area surrounding orangutan capture for translocation site 2.
Healthy Bornean adult female and infant that were reported seen in a community rubber plantation and captured for translocation. Year of capture (2018) is indicated with thick black bordered circle. Intact tropical moist forest, degraded tropical moist forest, and regrowth are combined into a single forest class (green). The map inset at the bottom is the location of the specific capture site and buffer (yellow) along with remaining locations where three other orangutans were captured for translocation (black)—one additional orangutan was captured for translocation in an area of Kalimantan outside this map. Basemap: Google Earth Engine. Forest map: EC JRC. Protected areas (purple): UNEP-WCMC and IUCN [60].
Table 2.
Mean annual translocation removals as a percent of population size. Mean annual species and provincial population estimates were calculated from Santika et al. [38], Voigt et al. [19], Utami-Atmoko et al. [43], and Wich et al. [18] (see S4 Table for details). Translocation removals are individuals captured from the wild for translocation but not immediately released into another wild population.
Table 3.
Impact of reported translocation removals and estimated killing offtake. Orangutan killing estimates are calculated from the mean, minimum, and maximum rates in Meijaard et al. [61] and crime detection rates of 1.2%–10% from Sherman et al. [56].