Mapping Distribution of Butterflies in Central Bobiri Forest Reserve And
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Mapping distribution of butterflies in central Bobiri Forest Reserve and investigation of logging and stage of regeneration on butterfly species richness and diversity. Addae-Wireko Louis March, 2008 Mapping distribution of butterflies in central Bobiri Forest Reserve and investigation of logging and stage of regeneration on butterfly species richness and diversity. by Addae-Wireko Louis Thesis submitted to the International Institute for Geo-information Science and Earth Observation (The Netherlands) and Kwame Nkrumah University of Science and Technology (Ghana) in partial fulfilment of the requirements for the degree of Master of Science in Geo-information Science and Earth Observation, Environmental Systems Analysis and Modelling (ESAM) Specialisation Thesis Assessment Board Prof. Dr. Ir. Alfred de Gier, Chairman, Degree Assessment Board, ITC (chair) Dr. B. K. Prah (External Examiner) Dr. S.K. Oppong, Internal Examiner, KNUST Ir. Louise M. van Leeuwen, Course coordinator, ITC Dr. William Oduro, First supervisor, KNUST Supervisors: Dr. Jan de Leeuw (ITC), Dr. William Oduro (KNUST), Mr. J. Quaye Ballard (KNUST) INTERNATIONAL INSTITUTE FOR GEO-INFORMATION SCIENCE AND EARTH OBSERVATION, ENSCHEDE, THE NETHERLANDS KWAME NKRUMAH UNIVERSITY OF SCIENCE AND TECHNOLOGY, KUMASI, GHANA Disclaimer This document describes work undertaken as part of a programme of study at the International Institute for Geo-information Science and Earth Observation and Kwame Nkrumah University of Science and Technology. All views and opinions expressed therein remain the sole responsibility of the author, and do not necessarily represent those of the institutions. Abstract The contribution of remote sensing data to the mapping and prediction of invertebrate diversity is poorly investigated and even when done, much of these have focused on pests rather than for conservation purposes. This study sought to map the distribution of selected butterflies in central Bobiri Forest Reserve using Genetic Algorithm for Rule-set Production (GARP) and Maximum Enthropy (Maxent) methods with presence data only. Distributions of six common butterfly species of Ghana were successfully mapped in the study area. Receiver operating characteristic curves for eight (8) distribution maps were outstanding with four being excellent. There was not much difference between the distribution maps generated with all predictor variables considered and those with the best five predictors in terms of AUC. Maxent maps generally had higher AUCs when ROC curves were plotted. Distance to rivers, Enhanced Vegetation Index (EVI), Elevation and Distance to roads were the most relevant predictors of species distribution. Enhanced Vegetation Index performed better than Normalised Difference Vegetation Index (NDVI) and Soil Adjusted Vegetation Index (SAVI) in predicting species distribution. A Kruskal-Wallis test of butterfly diversity indices of three forest classes with different levels of disturbance and at different stages of regeneration revealed significant differences (P<0.0001) in all the three diversity indices used (Fisher’s Alpha, Shannon-Weiner and Simpson’s Inverse diversity) with further post tests (Dunn’s multiple comparison) of forest blocks showing significant differences (p<0.001) for all diversity indices. The recently logged and the not logged blocks were the most similar, with 61 common species and a Morista-Horn Index of 0.951. Although the recently logged (RL) had higher numbers of captures and rarefied abundance of individuals than the not recently logged (NRL) and unlogged (NL), it was also the least diverse with regard to Simpson’s inverse diversity index. Therefore every effort should be made to prevent degradation of the forest which would allow few species most suited for degraded areas and secondary forests to greatly benefit at the expense of specialists found in forests in pristine conditions. i Acknowledgements To God most high for making this study possible. My profound gratitude goes to my supervisors Jan de Leeuw, William Oduro and Jonathan Quaye Ballard. I owe this work to you and it would not have been possible without your time, interest in my work and the constructive criticisms. I wish to thank the ITC, Wildlife and Range Management Department, FRNR, KNUST and KAAD for their immense support in making the dream of undertaking this course a reality. I am especially thankful to Michael Weir and the coordinators of the GISNATUREM programme for the roles they played. To all my colleagues, staff of KNUST and Bobiri Forest Reserve, friends, family and all who contributed in diverse ways in making this work a success, I say God richly bless you. ii Table of contents 1. Introduction ...................................................................................................................................... 1 1.1. Background .............................................................................................................................. 1 1.1.1. Habitats ............................................................................................................................. 1 1.1.2. Biological indicators. ........................................................................................................ 2 1.2. Research Problem ..................................................................................................................... 3 1.3. Prior work ................................................................................................................................. 4 1.4. Research Aim ........................................................................................................................... 4 1.5. Objectives ................................................................................................................................. 4 1.6. Research Questions .................................................................................................................. 5 1.7. Hypothesis ................................................................................................................................ 5 1.8. Assumptions ............................................................................................................................. 6 1.9. Research Approach ................................................................................................................... 6 2. Methods and Materials ..................................................................................................................... 9 2.1. Study Area ................................................................................................................................ 9 2.1.1. Compartment Designation .............................................................................................. 10 2.2. Site Selection. ......................................................................................................................... 10 2.2.1. Sampling Design ............................................................................................................ 10 2.3. Data. ....................................................................................................................................... 11 2.3.1. Butterfly Sampling. ........................................................................................................ 11 2.3.2. Habitat Variables. ........................................................................................................... 13 2.3.3. Topographic Features ..................................................................................................... 14 2.3.4. Distance maps ................................................................................................................. 14 2.3.5. Satellite image processing .............................................................................................. 15 2.3.6. Modelling of species distribution ................................................................................... 15 2.3.7. Selection of model species ............................................................................................. 15 2.3.8. Development of Models ................................................................................................. 16 2.3.9. Evaluation of Models ..................................................................................................... 16 3. Results ............................................................................................................................................ 18 3.1. Intermediate maps for mapping distribution of species. ......................................................... 18 3.2. Sampling Effort ...................................................................................................................... 19 3.3. Distribution of trapped butterfly species among butterfly families. ....................................... 20 3.4. Distribution of captured butterflies among forest disturbance classes ................................... 21 3.4.1. Butterfly species richness of forest disturbance classes ................................................. 22 3.4.2. Butterfly diversity of forest disturbance classes ............................................................. 23 3.5. Distribution of captured butterflies among months. ............................................................... 24 3.6. Species Rank Abundance. .....................................................................................................