A BTUJlY ON SOlIS EGOLOGICJIL ASP.o;CTS Ob' THE GIAWJ: HOI)l~ ... R~'.'r T.'\CHYOnYC~E's HACnOCEPHALUS (nUPPEI,L,184z). IN lYILic HOUNTJ\INS, ETHIOPIA A Thesis Presented to School of Graduate Studies Addis Ababa University In Partial Fulfillment of tho Requirement for the Degree Muater of Sci onCe in Biology By Shimelis Beyene June 1986 i endemic to Ethiopia, waG 13i~u'li2d in two ohservutio!l llre~s at Bale Mountains National I'&lk i]l south eastern Ethiopia~ The burrow system 8Y.:cavated revBaled extensive underground tunnels, material consisting exclusively of grasses knitted into a hollow ball. One to several blind tlmnels ;iere found filled with foods to res and faec BE>. rJ~he underground tunnel SYR tems \'Jere marked by soil moundG, Garth plugs, foraging holes and haypiles resembled those of pocket gophers. Mole-rats spent an ave~Rge of about 70 minlltes a day on the surface, mainly foraL:inp; tut £1.1so observing ana. digging Q The time spent on the surface by mole-rats at high altitude was significantly greater thc1.n that spent by mole-rats .:;l.t low al ti tude. This difference appea.red to be related to the difference in vegetation cover. The populatiDn d(.nc;i ty of mole-rats 'lias estimated to be about 6000 mole-rats per kr/ at Sanetti and 570 mole-rats per 2 km at Badeae 0 l'his difference in population donai ty ;\'a8 probably due to differences in [;oil and vegetation types, it CompGtion with dom;)stic live stock at lovler al ti tudes might have also contributed. Mole-rats restricted their activities to the parts of their burrow system at higher ground in the vIet season and became freq~ently active in t11e tunnels at lower ground in the dry season. ii The major pr8datQ~ nrpc~rJd to be the Simioll fox (Canis .~ .. ----. Comparison '.';i th ot.'iel" rodent moles (Bathyergidae, Spalacidae Geomyidae) showed many conver~~ailt characteristics as a result of . t' the1r suberrane~n arlaptD.tion,s 0;> iii I wou].d like to express my deepest gratitude to my advisor Dr. J.G. Hillman whose extremely valuable advice and assistance made this study possible, I thank Dr, Hillman also for his permission to use his laboratory facilities at Dinsho and his equipment in the field, Dr. Hillman also offered helpful criticism of this manuscript. I am deeply indepted to Dr. Shibru Tedla, who suggested the title of this study, for his unfailing encouragement and for solving administrative problems. I would like to express illy sincere appreciation to Ato. Afework Bakele for his valuable advice and Dr. Amha Belay for his encouragement and f~r solving administrative problems. I am very grateful to Mr. 11. 'fakeishi, Kyushu Uni versi ty, Japan; Prof, D.'''. Yalden, Hanchester University, England; Prof. J.U.H.'Jarvis, University of Gape Town, South Africa; Prof. E. Neva, University of Haifa, Israel and Dr•. i,R., Arieli t , .Tel' A11i1l University, Israel for their important advice, suggestions and for sending me reprints. ~!y deep gratitude is extended to Dr, D, Humber and Wrt. Elizabeth Kebede for critically reading this manuscript. Hy sincere thanks must go to Dr. Zerihun Woldu who determined the cover abundance of plants and identified the plants. iv I would like to thank the staff of the Ethiopian ~ildlife Conservation Organization. In particular, Ato Teshome Ashine for his permission to work in Bale Mountains National Park, Ato Leyikun Abune, Ato TOflf3_ye Hundessa, Ato Abdu Mv.hamuod and Ato Tadesse Gebre Hichael for their encouragement and help. I am also grateful to Dr. Ermias Bakele, Ato T"shome Demssie and Ato loIulugata Ayele for havine facilitated the permission and to get attached to the ~'lildlife Conservation Organization. Ny thanks must go to the staff of Bale Nountains National Park. In particular, Ato Yitayale Kebede, Ato Hohamed Abdi, Ato Petros Andamo and Ato Neseret for their kind help in the field and for allowing me to use the park facilities. I gratefully acknowledge the Swedish Agency for Research Cooperation (SAREC) for financial support used to cover part of the expenses incurred in tllis work. Finally, I would like to express my warmest appreciation to all my friends who helped in this work in one way or another. v l~BSTRi\CT ..•.•..•.•••••••.••••••••.•••••••••••••••••..••••• ACKNOiILEDGEf.lENTS ..•..••••..•.•..•••••••..•.•••..••.•••.••• TJ-,\BLE OF CONTEt~~rS ••••••.•••••••••••••••••.•••••••.••.••••. LIST OF TABLES •.•..•••••.••.•••.•••••..•••.••..•...•..•.•. LI.:3T OF FIGURES ......•.••..•..•........................... INTRODUCTION .• . .. .............................. 1 THE STUDY Al'Ef, ....•••••• 5 Sanetti plateauo ..... ~." ...... o •••• o •• ~................. 5 Badeae .•.. ~ ........ t ... " I> 0 ..... 0 •• 0 .. .. .. • • • • .. • • • • • • • • • • • .. • • • • 6 DISTRIBUTION .... ' ........................... 9 HATERIALS AND Hj'THODS. • • • • . • • • . • • • • • • • • • • • • . • • . • . • • . • • 12 Trapping 0 • 00 ... 0 ...... " .... "" ... " ....... " ..... ~ .......... '"'' •• 16 ) LITERATUllE REVIK!I. ..00.·.0 ...... 00 ...................... 17 Burrow System. 00 ... 0 •••••••••••••••••••• 17 Mole-hill (Soil wound). .o •.• o.~.· ......... · ..•. o 18 Hay pile ........... 0 ....... 0 .. .. • • • • • .. • .. .. • .. .. • .. • • • .. .. • .. .. • • • 19 Foraging tunnels .......... "~~ ....... " •• o,, ........... , 19 Nest .......... " ......... oo ......... 0 ......... o" •• • ••••••••• 20 Food stor~ chambers .. .0" .... 0 ................. " ...... 22 Bolt-hrle. ...... ~ ...... o .... " •• ooo ... " •••••• o ••••• oo ..... 22 Sani tory ch[unbers .. " .. <> " ............................................ ~ 23 Empty chambers ....... " .. 0 .... ~ ...... 0 .. .. .. .. .. .. .. .. .. .. • • .. .. .. .. .. .. 24 vi Page Activi ty llbvoe Ground" ........ 0" ••• • ..... 0 ••••••••• 24 Observing 0 • ...... 000 ......................... 25 :F'oragi11g........................................... .................... ........ 26 Digging • ••••• _0 ................................ 2\l Feeding •.••• ....................................... 27 Population Density ..................... " .............................. .. 27 Predation . •••••• 00.0" ............................ 29 RESULTS III ............ .. ••••••••••••••••• 0.00 •••••••••••••••••• 31 Trapping ........... " ............................. 31 Burrow System. ••••••••• 00 •••••••••••••• , •••••••• 31 Soil mound • ................. 00 .................... 32 Hay pile" ............. .. • ., .. 00" ••••••• " ••••••••••••••••.• 32 Foraging tunnels • ................................ 0 .••• 35 Nest •• " •••••••• , ••••• " ................................. 35 Food store. •••• 0 •••• 0 ..... 00 ...................... ,. 35 Exposed parts of burrow system.".""."." ••••• "" _.. 38 vii Activity Above Ground ......... "." ................ "..... 24 Observing" ..................... " •• " ............ " • • • • 25 }'ora,gill(~ ....... 0 ........ " ... II •• " ••••• , ••• <> • • • .. • • • • • 26 Digging ........................................... 26 Feeding" ..... " ••• " .... " ........... , ................ " ••• " • • 27 Population Density. <I" ....... """" ..... " ...... " •• ",, ... ,,""" 27 Predation ••••• , ................................. ~ ••••• 29 RES ULTS •• " •• " .. " • " " ............ " ... " .......... " • " •• , ........ , " .• , • • • 31 Trapping .... " .. " " ••• " • " ...... 0 " ••• 0 " 0 " " " ••• " ... " " " • " .... " , 31 Burro\'1 System""" .. " ................ " ...................... ""... 31 Soil Inound .... " ............. ~ ................. "..... 32 Hay pi 1 e ....... , ....... " ..................... " . • • .. • • • 32 }l'oraging tunnels ...................... "............ 35 Nest ......... ........... 0 .... ., .................... 35 Food store •••• 0 .......... , ........... .. .. .. .. ... .. .. " 35 Exposed parts of burrow system ••••••• o......... 38 Activity Above Ground • .................................. o.~ 44 Observing" ................ 0 ........................... 44 Foraging ... ••••••• 00 ............................. " ••• 44 Digging, •• .......................................... 0 ••• 46 Total a.ctivity, ..... " ................................. 49 Po pula tion Densi ty, , ··.·0' .......... 00 •• " ............... 53 Predation, 0 •••••••••• 00 ......................... ••• 0 53 Breeding. 0' .... 00 ...................................... 54 viii Social Organization ......... ~ • 0 ........ o ......... ~ ...... Season3.1 l1igration ........................ 0 • • • • •• • • • • • •• • 56 Estimation of Cover JlbundnncG of plants.............. 57 DISCUSSION ••..•.••••••••••••••••••••.••••••....•••••.•...• 61 Burro\v Syst81n ~ ......................... " • • • • • •• • • • •• •• • 61 Soil mounds .................... 0 ............. ,. .. • •• ••• 61 Hay pile ..... 0 ....................................' • • • • 62 Foraging tunnels ~. , ..... 0 ........ 0 • 0 ......... " •• 0.. .. 63 Nest D.nd nesting Hl.:1torials ~.......................... 67 }c'ood store ........................ 0 • .. • • • • • • • • • • • • • • • • • 69 Bolt-hole ............................................ 70 Exposed parts of burrow system....................... 71 Activi ty Above Ground·••••••••••• 0.. •• • • • •• • • •••• .... .... 72 Observing ..................- ............... '" •• '" •• • • • 72 Foraging ................... ~ •••.•.•.•• 5 ............. 73 Digging ......... " ........................................... 74 Total activity........................................... 75 'Population Density... ••••••••••••.••••..• ••.••.••••••