Forest Structure Shapes Tropical Terrestrial and Arboreal Mesomammal Communities Under Moderate Disturbance

University of Rhode Island DigitalCommons@URI Open Access Master's Theses 2021 FOREST STRUCTURE SHAPES TROPICAL TERRESTRIAL AND ARBOREAL MESOMAMMAL COMMUNITIES UNDER MODERATE DISTURBANCE Juliana Masseloux University of Rhode Island, [email protected] Follow this and additional works at: https://digitalcommons.uri.edu/theses Recommended Citation Masseloux, Juliana, "FOREST STRUCTURE SHAPES TROPICAL TERRESTRIAL AND ARBOREAL MESOMAMMAL COMMUNITIES UNDER MODERATE DISTURBANCE" (2021). Open Access Master's Theses. Paper 1968. https://digitalcommons.uri.edu/theses/1968 This Thesis is brought to you for free and open access by DigitalCommons@URI. It has been accepted for inclusion in Open Access Master's Theses by an authorized administrator of DigitalCommons@URI. For more information, please contact [email protected]. FOREST STRUCTURE SHAPES TROPICAL TERRESTRIAL AND ARBOREAL MESOMAMMAL COMMUNITIES UNDER MODERATE DISTURBANCE BY JULIANA MASSELOUX A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN BIOLOGICAL AND ENVIRONMENTAL SCIENCES UNIVERSITY OF RHODE ISLAND 2021 MASTER OF SCIENCE IN BIOLOGICAL AND ENVIRONMENTAL SCIENCES OF JULIANA MASSELOUX APPROVED: Thesis Committee: Major Professor Brian Gerber Nancy Karraker Emi Uchida Ying Zhang Brenton DeBoef DEAN OF THE GRADUATE SCHOOL UNIVERSITY OF RHODE ISLAND 2021 ABSTRACT Tropical biodiversity is threatened globally by anthropogenic disturbances, particularly forest degradation and overhunting. Where large mammals have been extirpated, smaller-bodied “mesomammals” may play an important ecological role (e.g., as seed-dis- persers). However, mesomammals are routinely understudied as they tend to be rare, cryptic, and nocturnal. Tropical tree-dwelling (arboreal and semi-arboreal) mesomammals are especially vulnerable to forest conversion, particularly when reliant on old growth forest structures. Understanding species- and community-level responses of terrestrial and arboreal mesomammals to changes in forest structure and human activity is crucial for informing management decisions in protected areas where resources are lim- ited. We deployed 20 arboreal and 75 terrestrial camera traps throughout Nam Cat Tien National Park, southern Vietnam. The study objectives of the first chapter were to 1) identify long-term changes in terrestrial mesomammal richness and 2) evaluate the effects of forest structure and anthropogenic disturbance on an 18-species mesomammal community using community occupancy models. The objectives of the second chapter were to 1) evaluate the utility of arboreal camera traps for surveying nine arboreal and four semi-arboreal tropical mesomammals, 2) model the effects of forest structure and anthropogenic disturbance on detection and occurrence of arboreal mesomammals using generalized linear mixed models and single-season occupancy models, and 3) estimate arboreality of semi-arboreal species using multi-scale occupancy models. We found that terrestrial mesomammal site occupancy was driven largely by the interaction between distance to seasonally inundated grassland and absolute forest cover (basal area per hec- tare). We found no negative effects of anthropogenic factors at the community-level. However, we did find that four disturbance-tolerant small carnivores have been extirpated since the 1990s and continued human presence in the park suggests that hunting and snar- ing remains an acute threat to native mesomammals. We also found that canopy connec- tivity and other mature forest characteristics were important across the arboreal community. The effect of tree and focal limb characteristics on species detection was most likely explained by physiological adaptations and tree use behavior. Mean occupancy was un- derestimated for most semi-arboreal species when only one method was used. Multi- method occupancy designs may thus improve estimates of species distribution and habitat use, which are important for guiding management and conservation decisions. ACKNOWLEDGMENTS I would like to thank my advisor Dr. Brian Gerber for his exceptional support throughout all phases of the project. I would also like to thank my wonderful field assistants Quy Tan Le and Jessica Burr without whom this project would not have been possible, and Cat Tien National Park for providing permissions and personnel to conduct this research, in particular Dr. Khanh Phamhuu, Luong Pham Hong, and the park rangers who regularly accompanied the field team and revisited cameras. I would also like to thank Save Vietnam’s Wildlife for their assistance in setting up project logistics. Additional thanks to the undergraduates who volunteered their time to help tag camera trap images, Emma Paton, Kylie Hernandez, and Maegan Shanaghan. I am grateful to Dr. Emi Uchida and Dr. Nancy Karraker for their invaluable feedback. This work was supported by the USDA National Institute of Food and Agriculture, Hatch Formula project 1017848. iv PREFACE The two chapters of this thesis have been provided in the manuscript format of the respective journals they were submitted to. Manuscript 1 follows the Ecosphere journal guidelines, and Manuscript 2 follows the Animal Conservation journal guidelines. All tables, figures, and appendices for both chapters are included at the end of Manuscript 2. All literature cited for both chapters are combined in the Bibliography section. v TABLE OF CONTENTS ABSTRACT.................................................................................................................... ii ACKNOWLEDGEMENTS ........................................................................................... iv PREFACE ....................................................................................................................... v TABLE OF CONTENTS............................................................................................... vi LIST OF TABLES ........................................................................................................ vii LIST OF FIGURES .................................................................................................... viii MANUSCRIPT 1 ........................................................................................................... 1 INTRODUCTION....................................................................................................... 2 METHODS.................................................................................................................. 6 RESULTS.................................................................................................................. 13 DISCUSSION ........................................................................................................... 16 MANUSCRIPT 2 .......................................................................................................... 21 INTRODUCTION..................................................................................................... 22 METHODS................................................................................................................ 25 RESULTS.................................................................................................................. 31 DISCUSSION ........................................................................................................... 33 APPENDICES ..............................................................................................................49 BIBLIOGRAPHY ....................................................................................................... 137 vi LIST OF TABLES TA B LE PAGE Table 1. Real estimates of (a) site-level occupancy (ψ) and detection (p) from the most supported single-species model for nine arboreal species at the mean covariate value, and (b) site-level occupancy (ψ), station-level occupancy ( ) and station-level detection (p) from the top multi-method model for four semi-arboreal species at the mean covariate value .............................................................................................................................39 vii LIST OF FIGURES FIGURE PAGE Figure 1. (a) Biosphere reserve (as delineated by UNESCO; light green) and core protected area (dark green) zones of Cat Tien National Park, Vietnam. Our study was conducted in the Nam Cat Tien (dashed outline) region of the park. (b) Layout of camera trap sites stratified by habitat within Nam Cat Tien, Vietnam .....................................40 Figure 2. Interaction effect of site-level absolute cover at low (10% quantile, 255m), mean (1867m), and high (90% quantile, 3843m) distance to grassland on mean predicted community-level mesomammal occupancy with 95% credible intervals....................41 Figure 3. (a) Posterior effects on species and community detection probability on the logit-scale from the top model. The mean is indicated by the circle, 70% and 95% Bayesian credible intervals are indicated by the thick and thin lines, respectively. The dashed red line indicates 0 or no effect from the intercept (dry season). (b) Posterior effects on species and community occupancy probability on the logit-scale from the top model. The mean is indicated by the circle, 70% and 95% Bayesian credible intervals are indicated by the thick and thin lines, respectively. The dashed red line indicates 0 or no effect from the intercept (dry season) ..........................................................................42 Figure 4. Layout of paired arboreal-terrestrial camera

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