I.W. Watson et al. (1997b). Continuous and episodic demography. Appendix 3
Background (R)ecruitment and/or (M)ortality in arid zone shrub populations. (Y)es = Recruitment or mortality observed. (N)o = Recruitment or mortality not observed. Original data presented in the form of (a) densities or counts for total population, (b) actuarial (c) survivorship (d) turnover rates, (e) text or other. Table, Figure and page numbers are those of the original Reference (Appendix 6).
Species R MCountry Reference (see Appendix 6) Notes
bAcacia aneura YY Australia Cunningham & Walker 1973 (Fig. 1, Table 1) 1
aAcacia aneura, A. colletioides, Callitris columellaris (syn. glaucophylla), Dodonaea viscosa, Eucalyptus populnea, Eremophila longifolia, E. mitchellii, E. sturtii, Myoporum deserti, Olearia pimeloides (pooled) YY Australia Walker 1976 (Table 8.7)
aAcacia mellifera, Boscia albitrunca, Grewia flava, Lycium namaquense, Rhus tenuinervis, "other shrubs" YY Botswana Skarpe 1990 (Fig. 2a)
c,eArtemisia tridentata, Gutierrezia sarothrae, Leptodacylon pungens YY USAWest et al. 1979 (Fig. 1, Table 1 & P 384) 2
aAtriplex paludosa, A. rhagodiodes, Cratystylis subspinescens, Maireana (syn. Kochia) pyramidata YY Australia Wilcox 1974 (Figs 4a,b)
a,dAtriplex vesicaria YY Australia Eldridge 1989 (Figs 2.3a,b); Eldridge et al. 1990 (Figs 2 ,3, 4) 3
bAtriplex vesicaria YY Australia Graetz 1980 (Table 3)
a,c,e Atriplex vesicaria YY Australia Hall et al. 1964 (Figs 11, 12, 14), Crisp 1978 (Fig. 1 & P 527) 4
a,bAtriplex vesicaria YY Australia Hunt 1995 (Figs 5.2, 5.3, 5.5) 5
bCarnegiea gigantea, Cercidium spp. YY Mexico Turner 1990 (Tables 3 & 4) 6
b,eCassia nemophila YY Australia Silander 1983 (Table 2, P 230) 7
c,eChrysothamnus nauseosus YY USAToft 1995 (Fig. 3b & P 3) 8
aEremophila forrestii (syn. E. leucophylla), E. spectabilis, Frankenia pauciflora, Maireana glomerifolia, Ptilotus obovatus YY Australia Gardiner 1984 (Tables 12,32), 1986a (Figs 4,5), 1986b (Table 1)
a,b,dFrankenia pauciflora, Maireana georgeii, M. glomerifolia, M. pyramidata, Ptilotus beardii, P. obovatus YY Australia Yan et al. 1996 (Table 2 & Figs 2, 3, 4) 9
bLarrea tridentata YY Mexico Turner 1990 (Table 2) 10
aMaireana (syn. Kochia) sedifolia YY Australia Trumble & Woodroffe 1954 (Table 3) 11
a,dMaireana astrotricha YY Australia Eldridge 1989 (Fig. 2.5); Eldridge et al. 1990 (Table 3) 12
bMaireana pyramidata YY Australia Milthorpe 1978 (Figs 1,2)
eAcacia aneura Yn/a Australia Burrows 1973a (Pp 57, 66) 13
eBrownanthus ciliatus, Ruschia spinosa, Galenia fruticosa, Pteronia pallens, Osteospermum sinuatum Yn/a Sth Africa Wiegand et al. 1995 (Pp. 2208-2211, 2215) 14
c,eAcacia aneura NY Australia Crisp 1978 (Fig.7 & Pp. 525-6) 15
b,eAcacia victoriae NY Australia Grice et al. 1993 (Tables 3, 5 & P 15) 16
a,dMaireana pyramidata NY Australia Eldridge 1989 (Fig. 2.6); Eldridge et al. 1990 (Table 3) 12
c,eMaireana sedifolia NY Australia Crisp 1978 (Fig. 3 & P524)
cAcacia burkittii n/aN Australia Crisp & Lange 1976 (Fig. 5) 17
eAcacia victoriae n/aY Australia Reid et al. 1992 (Table 1 & P 220)
cArtemisia tridentata (ssp. tridentata) n/aY USAOwens & Norton 1990 (Table 2, Figs 1, 2) 18
cAtriplex vesicaria n/aY Australia Wilson et al. 1969 (Table 2)

Footnotes, Appendix 3 (Watson et al. 1997b)

1) Recruits were observed three times in 14.6 years (8 samplings) which included two severe droughts. The third cohort was observed at the final sampling so that it is not possible to tell whether recruits remained in the population.

2) The best-fit mortality curves for the first 11 yrs were log-log, i.e. each cohort has periods without significant mortality but the population probably experiences continuous mortality.

3) Recruitment was observed in 20 of 21 samplings (Eldridge & Westoby 1991). Mortality was observed in 20 of 21 samplings.

4) Data from Koonamore Vegetation Reserve. Most detailed data was found in Hall et al. (1964) but Crisp's (1978) paper is often cited. See also earlier, more detailed reports by Osborn et al. (1935) and Wood (1936).

5) Recruitment was observed between 7 of 12 (close to stock water) and 11 of 12 (far from stock water) samplings. Mortality was observed between 10 of 12 and 12 of 12 samplings. Sampling interval was six months, except for one period of 12 months.

6) The period 1907-1959 was excluded because interval was too long.

7) Data was from Koonamore Vegetation Reserve, but summarised as age specific life tables and transition matrices. See also Hall et al. 1964 for data summaries.

8) Recruits were observed three times in nine years (9 samplings), including one drought. The third cohort was observed at the final sampling so that it is not possible to tell whether recruits remained in the population.

9) Data for M. georgeii, M. pyramidata, Ptilotus beardii taken from Yan et al. (1996). Turnover rates only are given for F. pauciflora, M. glomerifolia and P. obovatus, more detailed data obtained from Z. Yan (pers. comm.).

10) The period 1907-1960 was excluded because sampling interval was too long.

11) Densities were estimated from 64 permanent plots each 40.5 m2 (Woodroffe 1941) rather than cartographic data. Crisp (1978) cited Burbidge (unpubl.) as expressing doubt on such high establishment.

12) Actuarial data was from Eldridge (1989). Turnover rates were from Eldridge et al. (1990).

13) Burrows (1973a) was included in this table (although not a longitudinal study and one which included regeneration on some plots following extensive mechanical disturbance) because the study was designed to investigate the ease of regeneration of A. aneura in response to concern at poor regeneration in other parts of Australia.

14) Although this study reports on a simulation model, seedling survival and establishment rules were based on empirical data. Milton (1995) studied seedling emergence and survival at the same site. In the model, mortality occurred deterministically after each plant reached its 'maximum age'.

15) Osborn et al. (1935), Wood (1936) and Hall et al. (1964) suggest that germination of A. aneura at this site is more frequent than "rare" but seedlings are killed by feral (introduced) rabbits (Oryctolagus cuniculus).

16) These data were presented as mortality by size class rather than cohort. The period 1981-1992 was excluded because the sampling interval was too long.

17) These data were from Koonamore Vegetation Reserve. Five of five individuals remained alive for >30 years. Crisp & Lange (1976) suggest that "... input to the population is continuous" but this was based on size structure determination.

18) Zero mortality was observed for the largest size category of plants in the "SDG" treatment.


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