Ecological iSuccKssioN Observed During KegeneraTton 
OF Tkiodia Puxgens H.Br. After Burning, 15o 
Warrajong- and on adjoining- ]>i’o|)crli(‘s, whore major changes in the vege- 
tation can he recognised. The Triodia on these -areas has l)een destroyed 
aiifl re])laeed with an Erafjvosfi.'^ eripoda-douunixni association. This dis- 
turbance of tile normal se(]uence is not- merely a retrogressive change in the 
succession and it seems best to define it as a di'iclim(f r. That the disclimax 
is a “permanent” change is indicated l)y the fact that in one place the coarse 
Avoolly bases so chai’acteristic of Eracjrosii-^ eripoda averaged 20 cm. in 
diameter. A<'cording to report this ret)i'('sented more than fifteen v(‘ars of 
growth. The basic causes of the change seem to lx* burning followe<l by 
prolonged and h(‘avy stocking. Whether burning was a i>rimary cause in 
all cases could not be proved. In this Kraprostis association seedlings of 
Triodia puugevi^ were absent and it is doubtful if they could establish them- 
selves against the ti(‘rce competition. That the country formerly ('arried 
Triodia pnngem^ is known from rcj^ort and from the e.xistence of isolated 
tussocks of this sp(‘cies among the Krarp-ostis; plants. Other jdants ])resent, 
both ephemeral and perennial, were the same as those in a normal Triodia 
p H nge n .9- a sso c i a t i o n . 
In one ai'i'a, on the adjoining propei’ty of Kginbah, there were indica- 
tions that the Eragrostifi cf/;;ode-association was being removed in its turn 
by the grazing animal. The result was a growth of annuals in which MoUugo 
mollaginis, Aristida aremtria, A. Inpjroiactrira and Polaniria icosandra were 
the most ini])ortant species. This repi'esents a retui’ii to the condition seen 
in the early stages of the sere on a bai’e area. 
SUMMARY. 
Burning of Triodia pangens results in either the destruction of the 
tussock with regeneration from seedlings or a viable butt remains whiidi 
spi’outs again almost immediately. 
In the coastal region, l)etween Port lledland and the northern end of 
the 80-Mile Beach, a viable butt is left, but inland along the Shaw, Coongan, 
and I)e Grey Rivers the tussocks are usually destroyed. 
Quadrats showing stages in i-egeneration after burning are figured and 
discussed. These were mai)[)ed in or u(*ar the experimental plots at Warra- 
long Station. 
A s(‘re is delined. The climax is one in which small trc(‘s and shrubs 
are associated with the dominant Triodia pnnfjavs. Ephemeral gi’owth is 
scanty in the mature stage. 
A permanent change in tin* vegetation, diu' to tire and the grazing 
animals, is des{'rib(*d. 
ACKNtnV LE I )G MENTS. 
The work desci'ibeil in this ])aj)er was mad(‘ j^ossible by the granting 
of the use of certain facilities by Professor G. A. (hxrrie and Mi*. A. M. 
Stewart of the Institute of Agricultui'e, University of Western Australia. 
The author also wishes to ex]>ress hex- ap])reciation of the hospitality of Mr. 
and Mrs. Eraxd<. Ilardie of Warralong Station, also for assistanct' in the 
Held from Mi’. Frank i\rel\ille of the Institute of Agriculture, 
