The Case of Woody Vegetation Patchiness and Beetle
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Ben-Gurion University of the Negev Jacob Blaustein Institute for Desert Research Albert Katz International School for Desert Studies Linking Landscape and Species Diversities: The Case of Woody Vegetation Patchiness and Beetle Species Turnover Thesis submitted in partial fulfillment of the requirements for the degree of “Master of Science” By Yuval Berger February 2006 Ben-Gurion University of the Negev Jacob Blaustein Institute for Desert Research Albert Katz International School for Desert Studies Linking Landscape and Species Diversities: The Case of Woody Vegetation Patchiness and Beetle Species Turnover Thesis submitted in partial fulfillment of the requirements for the degree of “Master of Science” By Yuval Berger Under the Supervision of: Prof. Moshe Shachak Marco and Louise Mitrani Department of Desert Ecology Dr. Elli Groner Marco and Louise Mitrani Department of Desert Ecology Author’s Signature………………………………….. Date……………………. Approved by Supervisor……………………………. Date……………………. Approved by Supervisor……………………………. Date……………………. Approved by the Director of the School …………… Date……………………. Table of contents Acknowledgements iii Abstract vi List of Figures vii List of Tables xi 1. Introduction 1 Conceptual framework for discussing biodiversity 1 Landscape Diversity 2 Species diversity 3 Environmental factors, landscape diversity and species turnover 4 Ecosystem engineers 8 Woody vegetation as ecosystem engineers 12 Purpose of this work 15 Hypotheses 16 2. Filtering as a linkage between patchiness and species turnover – theoretical considerations 17 Definitions 17 The model 20 3. Methods 26 Experimental design 26 Focal group and specimen identification 30 Study sites 30 Scale definition 33 i Dominance 34 Patch contrast 34 Assemblage contrast 35 General Patterns 43 4. Results 44 Dominance 44 Sunfleck contrast 50 Assemblage contrast 56 5. Discussion 73 Research hypotheses 73 Canopy removal, grazing and species composition in Mediterranean woodland 75 Combined effects of grazing and canopy removal on woody-open assemblage contrast in Mediterranean woodland 77 Inhibition and facilitation of beetle activity by ecosystem engineering 79 Canopy removal, grazing and species composition in desert shrub-land 81 Assemblage contrast response to engineering under different environmental conditions 83 Linking landscape and species diversities 88 6. References 90 7. Appendices 106 ii Acknowledgements This work couldn't have been completed hadn't it been for the help of many and it is a pleasant duty to thank them here. My mother Yael, my sister Rachel (Weu), my friends Gali, Oren, Maya, Ofek, Laurie, Sigal and Anat, were all ready to offer their care and support when such was needed. Dr. Elli Groner introduced me to the fields of community ecology and ecological entomology, and was an inexhaustible source of advice during the entire period of my study. His wife Zoe and he did their best to make me feel at home in Sede-Boker right from the very beginning and always offered their help both in academic and personal issues. Prof. Moshe Shachak shared with me his vast scientific and life experience, introduced me to the world of ecosystem ecology and led me through the process of developing the conceptual framework of this study. Studying under his supervision was a unique intellectual experience, which helped me in developing my ecological and scientific thinking. I consider the stormy scientific discussions taking place in his office one of the most important components of my academic education. I was privileged to have known and be taught by Prof. Yael Lubin. Yael was a member of my academic committee, a PI in the research project accommodating my study, and was more than once a source of sound advice. In addition she willingly volunteered to help in field work. I consider Yael a role model when it comes to interpersonal relations, ethics, tuition and science. Mrs. Yael Kaplan and Mrs. Dorit Levin were always there to insure that red tape will not stand in the way scientific progress. Both exercised a most accommodating attitude and were extremely helpful. Marc Goldberg made sure that technical issues will be of little obstacle and as many of my fellow students I enjoyed iii the reliable technical infrastructure that Marc has managed so well. During my research I enjoyed the cooperation of the Israel Nature and National Parks Authority (INNPA). Dr. Yehoshua Shkedi manages the Adulam LTER station and was always willing to help. Ilan Shifman is the park ranger in Adulam and played a most valuable role in coordinating grazing with sampling. Dr. Linda Whittaker from the science division of the INNPA led me in my first steps through the maze of multivariate analysis. In Avdat I enjoyed the friendship and help of Jumaa Zanoun, who kept an eye on the station at all times. Dr. Marti Jane Anderson from the University of Auckland placed her excellent computer programmes at public disposal and by doing so raised an unparalleled contribution to my study. Dr. Vladimir Chikatunov from the Tel-Aviv University helped identifying the beetles of Adulam. Dr. Bertrand Boeken readily discussed with me theoretical and methodological aspects of my work and supplied me with valuable insights. Prof. Burt Kotler unknowingly contributed to the development of my research question as submitting an assignment in his course "Classic readings in Ecology and Evolution" I realised the importance of species composition and turnover. Prof. Mike Irwin, Dr. Sol Brand, Dr. Yaron Ziv, Dr. Yoram Ayal, Dr. Ariel Novoplansky, Dr. Pedro Berliner and Ido Filin gave me useful advice on academic and scientific issues. My lab mates and friends in Sede-Boker helped either in field work or in advice, amongst them are Moran Segoli, Efrat Shefer, Ofri Gabai, Alagie Manjang, Amadou Camara, Bimala Shrestha, Diana Milman, Efrat Elimelech, Efrat Gavish, Vania Portugal, Natela Mirzoyan, Felix Cervants, Adriana Guarerro, Evelin Farfan, Oren Shelef, Reuma Arusi and Yafei Wang. Iris Musli ,Yonatan Rosenzweig, Amram Tzabari , Hofesh Maoz, Ilana Dolev, and Nimrod Musli all helped in field and laboratory work. The Mitrani Department of Desert Ecology iv granted me with partial fellowship in my first year of study. Special thanks to Prof. Uzi Motro, who encouraged me to pursue the scientific path. v Abstract Biodiversity refers to the diversity of landscape entities (e.g. patches), species entities (e.g. communities) and resources (e.g. light). This work focused on the relation between patchiness (landscape diversity) and species turnover, which is a component of species diversity. To link between the two diversity forms I considered species assemblages as landscape entities, and species turnover between them was as a private case of contrast between landscape entities termed assemblage contrast. A conceptual model was used for describing species turnover and environmental filtering of species in a patchy landscape. The model has shown that the level of environmental filtering in a patchy landscape determines the assemblage contrast between different patch types. A field experiment examined the connection between patchiness induced by ecosystem engineering and species turnover under different environmental conditions. Abiotic patchiness caused by woody vegetation served as a model for patchiness induced by ecosystem engineering, and beetles (Coleoptera) served as a focal group for measuring species turnover. Two study sites, Adulam and Avadat (Israel), were used to represent two different ecosystems (Mediterranean woodland and desert shrub-land correspondingly). Experimental manipulations included canopy removal of woody vegetation and grazing. Beetles were sampled using pitfall traps. Dominance and woody-open assemblage contrast were calculated for beetle assemblages. Patchiness resulting from ecosystem engineering was shown to affect assemblage contrast, due to different mechanisms under different environmental conditions. Keywords: Landscape diversity, Species diversity, Assemblage contrast, Environmental filtering, Ecosystem engineers, Mediterranean woodland, Desert shrub-land, LTER, Woody vegetation, Coleoptera, Canopy removal, Grazing, Pitfall traps, Bray-Curtis distance, PERMANOVA, Non-metric multidimensional scaling. vi List of figures Figure 1.1 – Ecosystem engineering and its connection to species turnover 11 Figure 2.1 – Filtering and species turnover in a landscape with two patch types 21 Figure 3.1 – LTER stations in the research programme titled " Biodiversity patterns and processes in water-limited ecosystems: a unifying approach" 26 Figure 3.2 – Illustration of a single block in the experimental design 29 Figure 3.3 œ Assemblage contrast between hypothetical samples of table 3.1 calculated using Bray-Curtis distance 37 Figure 3.4 – Five scenarios where assemblage contrast between two patch types is being observed 40 Figure 4.1 – Dominance values for each patch type and treatment combination in Adulam 45 Figure 4.2 – Combined effect of removal treatment and patch type on dominance in Adulam 46 Figure 4.3 - Interaction between removal treatment and patch type effects on dominance in Adulam 47 Figure 4.4 – Dominance values for each patch type and treatment combination in Avdat 2005 48 Figure 4.5 – Woody-open sunfelck contrast under different combinations of removal treatment and grazing regime combination in Adulam 50 Figure 4.6 – Effect of removal treatment on woody-open sunfleck contrast in Adulam 51 Figure 4.7 – Woody-open Sunfleck contrast values for each treatment combination in Avdat