Land Use Change in Papua, Indonesia – Assessing Deforestation Patterns and Predicting Future Hotspots of Habitat Loss to Inform Spatial Conservation Planning
Land Use Change in Papua, Indonesia – Assessing Deforestation Patterns and Predicting Future Hotspots of Habitat Loss to Inform Spatial Conservation Planning
by Christoph Parsch née Parsch
Date of Examination:2025-01-10
Date of issue:2025-05-08
Advisor:
Referee:Prof. Dr. Holger Kreft
Referee:Prof. Dr. Matthias Waltert
Persistent Address:
http://dx.doi.org/10.53846/goediss-11221
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Abstract
English
New Guinea, the world’s largest tropical island, harbors some of the most biologically diverse and unique ecosystems. Despite its global ecological significance and endemic biodiversity, the region remains one of the most understudied environments. While land-use change and associated deforestation have extensively impacted tropical regions worldwide, New Guinea has thus far been spared from widespread agricultural conversion, leaving vast tracts of its pristine forests undisturbed. As the region has recently been described as a new frontier for development, New Guinea has reached a crossroads between accelerating environmental degradation and sustainable development policies entailing landscape-scale conservation targets, pledged in the Manokwari Declaration in Indonesian New Guinea and the Papua New Guinea Protected Areas Act. This political momentum on both sides of the politically divided island has prompted a critical need to investigate these developments by evaluating recent environmental policies, modeling future deforestation trajectories, and identifying key conservation priorities across New Guinea. The feasibility of the landscape-scale conservation targets pledged in the 2018 Manokwari Declaration is still uncertain. As the provincial governments of Papua and West Papua aim to protect 70% of Indonesian New Guinea’s land area, largely through the Indonesian social forestry program, critical questions regarding bureaucratic procedures, the extent of local participation, socioeconomic implications, and environmental impacts remain unresolved. The Papua New Guinea Protected Areas Act seeks to engage customary landowners in making their land available for government designation as protected areas through benefit transfers. However, challenges persist due to reservations about local support and sustainable financing for this initiative. Thus, one of the major challenges for New Guinea will lie in integrating bottom-up conservation initiatives with top-down policy and planning to align local aspirations for sustainable development with broader conservation goals for both people and nature. To forecast deforestation trajectories across New Guinea, I integrated machine learning and cellular automata to associate four deforestation scenarios (4.8–28% between 2020 and 2040) with their potential loss of ecosystem carbon. Areas of high deforestation risk were consistently forecasted in lowland regions across the four deforestation scenarios. In Indonesian New Guinea, 75% of deforestation was forecasted below ~380ma.s.l. but ranged higher in PNG (<750ma.s.l.). Land change-induced carbon loss varied largely across the four scenarios and ranged between 156–918 Mt in Indonesian New Guinea and 223–1082 Mt in PNG. Whether land change trajectories in New Guinea will follow those of other major tropical islands such as Sumatra or Borneo is uncertain and depends not only on local and regional governance but also on global demands for resources and agricultural products such as palm oil. Beyond the practical implications of these predictions, my analysis validates the potential for integrating random forests and cellular automata models to forecast high-resolution deforestation over large spatial extents. Building on the compiled deforestation trajectories, I identified spatial conservation priorities across eight biodiversity surrogates, assessed their congruence, and outlined conflicts with projected deforestation. The conducted systematic conservation planning exercise indicated that conservation priorities of the species composition of terrestrial vertebrates, as well as threatened, endemic, and gap species, species at risk from projected deforestation, functional and evolutionary distinctiveness, and ecoregions are largely incongruent. This incongruence reflects the complex distribution of New Guinea’s highly range-restricted biota. Achieving adequate representation of all vertebrate species within protected areas would thus require protecting at least two-thirds of the island of New Guinea. Therefore, short-term conservation efforts should focus on irreplaceable priorities at risk of deforestation. Proactive planning should aim to retain large continuous forest landscapes while balancing benefits for both people and nature. A better understanding of the region’s biogeography, alongside studies on global change scenarios and their impact on species distributions and priorities, would greatly benefit biodiversity conservation in New Guinea. This work may thus serve as a foundation for short-term policy advancement and as a primer toward more comprehensive systematic conservation approaches for the region. As deforestation increasingly threatens the future of New Guinea's pristine lowland forests and unique endemic biodiversity, expanding environmental and biodiversity research becomes essential for understanding the existing biodiversity, assessing potential losses, and identifying effective conservation strategies.
Keywords: Conservation; Land-use change; Indonesia; New Guinea; Deforestation; Conservation planning; Conservation priorities
