Studies of an Island Population of Rattus hscipes 



hv 



R \> ll.mMs 



VfiTJ little in vet known about the 

 ecology 61 thtC BfX^dJ mammals on 



Che islands of Bass Stiatt Some 



islands maintain only a population of 

 rabbits while olhei.s support tialivo 

 SpftcW TWO species of small mam- 

 mals inhabit Greater Glenn te Hand 

 the muiid rodent Riittm- fotsctpes »n<l 

 the ilasyuiid AiUirhinus minimus 



munthnux. 



In December I4b7. the Monash 

 UlMVeisity Biological Society Kuan a 

 studS of & fWUW which hail four 

 basic arms; — 



1. lo compare the morphological 

 characteristics with those of two 

 mainland populations of R. (ns~ 

 fipes. 



2. lo establish the densiiv of the 

 population and to compare il with 

 that normally occurring on ihc 

 mainland. 



3. lo determine the effect ol the 

 high population density on home 

 range. 



4. To establish the age structure 

 of the population with a view lo 

 linding out when the breeding 

 season was. 



Vu,i unON 



The majority of the Happing area 

 was covered in low scrub, varying 

 from two to six feet in height and 

 forming a dense canopy, the ground 

 cover in (his area was not very dense 

 but was composed ol decaying plant 

 material. I his was quite dry in the 

 summer. Interspersed among the 

 scrub were patches of tussock grass. 



The south-western section of the 

 trapping area was at a higher eleva- 



32 



tion I he vegetation there wis ( „ 1( ,. 

 urinu. In this section the y i man! 

 cover was also light. Toward die 

 lower section in the north . u -,i „ ( 

 the trapping area, were exposed 

 rocky patches with a mixed unci 0 | 

 tussock grass, low scrub and some 

 pig-face succulent. 



I he western section was exposed lo 

 strong winds carrying salt spray 

 However, only the extreme western 



began a tfappfog stations could he affected 



lad four by ,his as the sctub formed such 

 a dense canopy. 



Ml limns 



The trapping area lor intimation 

 of populalion density and rHNl S uir 

 was 3 d acres ( 14,600 square metrest 

 fighty trapping stations were marked 

 out. in ten rows of eight, each station 

 being fifty feci distant f:om i Is 

 nearest netghboui . 



The traps used were sitnilat to 

 National collapsible cage traps. 

 Twenty traps were used each trapping 

 night and were distributed over the 

 grid in three different ways; — 



1. The traps were evenly distn 

 butcd, each being two station- 

 distant from the" next. Every 

 night, they were rotated so that 

 after four successive nights, all 

 stations had been Happed. 



2. One quarter of the grid was 

 trapped in a block. The traps wen 

 shifted as a block SO lhat til 

 stations hail been trapped in tout 

 niehtv 



3 Random uumbcrs vseie chosen 

 each night. 



Vict N* V«l 88 



