Date of Award
2024
Document Type
Open Access Dissertation
Degree Name
Doctor of Philosophy in Forest Science (PhD)
Administrative Home Department
College of Forest Resources and Environmental Science
Advisor 1
Kristin E. Brzeski
Advisor 2
Jared D. Wolfe
Committee Member 1
Luke L. Powell
Committee Member 2
Tao Liu
Abstract
Central African tropical forests are rich in biodiversity and home to some of Earth’s most threatened mammals. However, mammals in the region are under increasing threat from habitat loss and degradation, coupled with an increased demand for wild meat. To conserve mammals, wildlife managers and community-led conservation efforts must understand the distribution and diversity of mammal communities. However, funding and logistical challenges make contemporary survey methods, e.g. ground surveys, difficult and expensive. Noninvasive methods allow efficient mammal diversity surveys with minimal field effort. Here, we use camera trapping and invertebrate-derived environmental DNA (“iDNA”) to assess mammal diversity and distribution in Equatorial Guinea (EG) in central Africa. First, we conducted a combined camera trap and iDNA survey to compare their effectiveness for mammal diversity surveys, and assessed diversity in a primary and secondary forest plot. A total of 40 species were detected, of which 17 species (42.5% of mammal richness) were detected only by iDNA. Camera traps detected a higher proportion of ungulates and larger-bodied rodents, while iDNA detected a higher proportion of primates, some carnivores, and small mammals. Higher species richness was detected in the primary forest plot, where this difference was only discernable through inclusion of iDNA data. This work supported the utility of combined surveys for elucidating cryptic differences in diversity between primary and human-modified forests, and of iDNA for the assessment of arboreal, rare, and small mammals. We next assessed human impacts affecting the presence and abundance of Endangered and hunted mammal guilds within a protected area (PA) using camera traps. We detected 32 species, with models indicating that pangolins and primates were more abundant further from the PA boundary, i.e. to its interior, possibly minimizing interactions with humans. Building upon insights from these models, we next developed occupancy models to determine environmental and anthropogenic factors affecting the distribution of mammal groups across mainland EG using camera trap data. Finally, we developed a predictive model for the eight Threatened species in EG, mapping predicted Threatened species richness across EG’s mainland, Región Continental. Our models indicated that threatened mammal distributions are largely driven by anthropogenic factors, e.g. forest degradation and roads. The predictive map indicated threatened species hotspots within some protected areas, and hotspots outside of protected areas: east of RNRC, in the portion of EG southeast of Monte Alén National Park, and in the southern portion of a newly-proposed PA near the developing capitol, Ciudad de la Paz. With recent, rapid development, mammals are likely to face increased threats in this region, and EG’s wildlife management agency, INDEFOR-AP, requires efficient survey methods and strategies to prioritize the allocation of scarce resources to areas at greatest risk. We recommend camera trapping and iDNA as rapid survey methods that can help managers prioritize regions for protection, e.g. within the newly-proposed PA.
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Recommended Citation
DeGroot, Tiff L., "ASSESSING TROPICAL MAMMAL DIVERSITY AND DISTRIBUTION USING NONINVASIVE METHODS", Open Access Dissertation, Michigan Technological University, 2024.