Date of Award
Summer 8-16-2024
Level of Access Assigned by Author
Open-Access Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Wildlife Ecology and Wildlife Conservation
Advisor
Alessio Mortelliti
Second Committee Member
Noah Charney
Third Committee Member
Malcolm L. Hunter, Jr.
Additional Committee Members
Shawn Fraver
Daniel J. Hayes
Abstract
For centuries, the Archipelago of Indonesia has attracted numerous naturalists worldwide, including Alfred Russel Wallace (1823-1913), who described this region as "the land of orangutan and the birds of paradise." This description alone implies the uniqueness of the archipelago’s fauna communities because those two animals represent two different biogeographical realms: Asiatic and Australian. Until about 6,000 years ago, the western part of Indonesia was connected to the Asian mainland and the eastern part was part of Australia, which explains how these biogeographical realms were formed (Lohman et al., 2011). Fauna communities in the Asiatic realm show similar characteristics with Asian wildlife, while animals in the Australian realm share similar traits with Australian wildlife. The area in between, known as the Wallacea, harbor animal communities that resemble both Asian and Australian wildlife. Because of this biogeography, Indonesia is extremely rich in biodiversity and was ranked as the second most biodiverse country in the world (Mittermeier, 1997; Myers et al., 2000). Despite its unique biodiversity, this country has among the highest number of threatened species globally (Baillie et al., 2004; Pereira et al., 2012), with habitat loss from severe deforestation as the primary threat (Giam, 2017; Margono et al., 2014). Moreover, research development in Indonesia is suboptimal, with many poorly understood species and regions. For example, researchers often focus on a few charismatic megafaunas, limiting studies on other less recognized threatened species in the country, such as the babirusas (Babyrousa spp.). Consequently, we lack knowledge on how habitat loss may affect these unpopular species, undermining potential actions to safeguard the country's biodiversity. My dissertation, structured into four chapters, explores research gaps in biodiversity issues in Indonesia, focusing on poorly studied taxa. Chapter 1 reports the status of research on Artiodactyla, an underrepresented mammalian order in Indonesia, throughout the archipelago. Following up, Chapter 2, 3, and 4 specifically examine an endangered Artiodactyla species endemic to the Togean Archipelago, the Togean Islands babirusa (Babyrousa togeanensis), and discuss potential strategies to conserve the species. This babirusa is one of the most poorly studied wild pigs in the world, with no prior field-based ecological study conducted before my research endeavors. In Chapter 1, I reviewed research articles covering Artiodactyla species throughout Indonesia and, as a comparison, Malaysian Borneo, aiming to identify biases in Artiodactyla research in the region. I found three sources of bias: 1) geographical bias, with most studies being conducted in the western part of the country and Malaysian Borneo, i.e., Asiatic realm; 2) taxonomic bias, with the number of papers covering the three most studied species equivalent to the number of papers covering the rest of the species combined; and 3) bias in research approaches, whereby few studies measured habitat selection and quality. To address these biases, I provide suggestions for future research priorities to develop knowledge on Artiodactyla-habitat relationships in Indonesia. One of the Artiodactyla species that requires more study is the Togean Islands babirusa which I will explore more in the following three chapters. Chapter 2 focuses on habitat selection of the Togean Islands babirusa. I deployed camera traps throughout the entire distribution range of the species to collect babirusa data and estimated habitat characteristics through remote sensing, GIS, and field measurements. I fitted single-season occupancy models to identify how habitat features affected the occupancy probabilities of the species. I found that the proportion of forests and mangroves positively affected babirusa occupancy, emphasizing the importance of protecting the remaining natural vegetation in the Togean Archipelago. However, we found that about 50% of the archipelago’s remaining forests are not protected, while about 30% of the protected areas (i.e., Togean Islands National Park) are non-forests. This indicates that the conservation strategies currently in place may not be effective to safeguard the babirusa. Moreover, there was not a standard protocol to evaluate whether our efforts to maintain the babirusa’s population were effective. Therefore, in Chapter 3, I developed a monitoring protocol to detect occupancy changes of the species over time. First, I divided the study area, based on the occupancy probability estimated in Chapter 2, into three categories: high, medium, and low occupancy areas. Then, I employed power analysis to estimate the required sampling efforts (i.e., number of camera trap stations) to detect 10-50% declines in babirusa occupancy. Realistically, the smallest occupancy declines this protocol can detect are 20% in high occupancy area and 40% in medium occupancy area. The low occupancy area is a low-quality habitat, and it requires unrealistically high sampling efforts to monitor, and can therefore be excluded. I also provided budgeting scenarios relevant to developing countries as guidelines to plan and perform species monitoring programs. Finally, Chapter 4 provides updates and new insights into the demography and behavior of the Togean Islands babirusa. Through N-mixture modeling, I estimated the population size of the babirusa as 341.49 – 580.48 individuals, with a sex ratio of 1:2.3. Males were mostly solitary, but females were usually part of groups of up to 11 individuals. I also performed multistate occupancy modeling and found that the probability of a reproductive babirusa being present in an occupied site was 0.741 and was positively affected by distance to human settlement. Despite high human pressure in the archipelago, the Togean Islands babirusa maintained its activity pattern during the day, with two peaks in early morning and late afternoon. My studies suggest that the Togean Islands babirusa should remain Endangered under the IUCN Red List Category and Criteria. To improve the conservation of the species, I recommend the following actions: 1) Revise the national park boundary to protect a larger forested area in the Togean Archipelago; 2) Regularly monitor the babirusa to detect occupancy changes overtime; 3) Integrate human-wildlife coexistence in management strategies and spatial development plan; and 4) Involve local communities in research and efforts to conserve the species.
Recommended Citation
Jati, Agus, "Conserving Underrepresented Taxa in Indonesia: Lessons From the First Ecological Studies of the Endangered Togean Islands Babirusa" (2024). Electronic Theses and Dissertations. 4067.
https://digitalcommons.library.umaine.edu/etd/4067