4.1 ManagementThelarge decrease in numbers and the increased extinction risk shown in all butthe three biggest populations (PSUs 1, 2 and 5) would suggest that nointervention is an unsuitable conservation method for the species. The modeldid not include the continued degradation of woodland which would likely leadto smaller carrying capacities and increased pressure on the smallpopulations. However, any managementplans put in place would need to be ecologically, financially and logisticallyviable (Kiss, 1990). Thetranslocation model is likely the most financially and logistically attractiveand given the long lifespan of the orangutan, infrequent translocations couldsignificantly improve the demographic and genetic stability of the smallerpopulations (Bruford, et al.
, 2010). Previous studies have shown that limitedintroductions of migrant genomes to a sub-population can drastically improvegenetic diversity, limiting the effects of inbreeding and genetic drift(Saccheri & Brakefield, 2002). However, the effects on social structure,animal health of both the source and sink populations must be taken intoaccount and any translocations must adhere to IUCNs guidelines. Thetranslocation of females every 50 years did not prevent high levels ofinbreeding in the smaller PSUs. However, both the 10 and 20 year models weremore successful, although neither model is likely to save PSU 10 and bothmodels show a large decline in population number for the source PSUs. Thiscould be alleviated by sourcing individuals from other populations such asanimals rescued from nearby plantations and nearby rehabilitation centres. The biggest issue with translocation is thatit does not offer a solution to ecological issues such as habitat degradationwhich is likely to continue.
Converselythe second simulation aims to combat the ecological issues that affect theorangutans of the wildlife sanctuary through the restoration of habitat and thecreation of habitat. The aim of the LKWS management plan is to eventuallyreconnect all of the PSUs. Both the demographic and genetic benefits of doingso can be clearly seen in the simulation, particularly of the smallerpopulations, although PSU 10 still has a significant chance of extinction.
Despite the use of realistic scenarios, the efficiency of this model isdependent on the speed at which the connectivity can be implemented. Manyfactors can influence this from financial, as more land will need to beacquired, to the rate at which the forests recolonise the areas and connectionsacross human habitats and roads. Therefore, any estimates need to be taken withcaution due to the difficulty of the implementing the connectivity. Giventhe inability of both the connectivity and translocation models to deal withissues surrounding the orangutans at the sanctuary, the mix approach may bemost suitable.
The combination of the 20 year translocation method, whichprovided the best proportional change in results across all PSUs, and theconnectivity method, which provided the largest mean population size and lowestcoefficient. This is likely the most realistic method for solving the issuesfacing the orangutans within the sanctuary.