Radiata pine (Pinus radiata D.Don) and red beech (Nothofagus fusca (Hook. f.) Oerst.) were grown for over 1 year at elevated (ELEV, 64 Pa) and ambient (AMB, 38 Pa) CO2 partial pressure in open-top chambers. Springtime measurements of overwintering leaves showed that light- and CO2-saturated photosynthetic rates (Amax) of pine leaves were similar for the two treatments (AMB: 6.7 � 1.08 μmol m-2 s-1, mean � 1 s.e.; ELEV: 6.6 � 0.47) but, for beech leaves, Amax was greater for AMB plants (8.8 � 0.90 μmol m-2 s-1) than for ELEV plants (6.10 � 0.71). Summertime measurements of leaves grown that spring showed that for pine, Amax was similar in the two CO2 treatments (AMB 14.9 μmol m-2 s-1 � 0.80; ELEV: 13.5 � 1.9) while, for beech, Amax was higher in AMB plants (21.0 � 1.1) than in ELEV plants (17.2 � 1.9), although the difference was not statistically significant. These results indicate downregulation of photosynthetic capacity of beech but not pine. Vcmax did not differ between treatments within species, suggesting that there was no acclimation of rubisco activity. Triose phosphate utilisation limitation may have contributed to the downregulation of Amax in beech. For pine, photosynthesis at treatment CO2 partial pressures was greater in ELEV plants in both spring and summer. For beech measured at treatment CO2 partial pressures, photosynthesis was greater in ELEV plants in summer, but was similar between treatments in the springtime.

The dynamics of populations of black beetle, Heteronychus arator (F.), in plots of paspalum (Paspalum dilatatum Poir), ryegrass (Lolium perenne L.), and ryegrass/white clover (Trifolium repens L.) pastures were studied. Life tables were constructed which quantified individual and generation mortalities and identified the key factors causing population change. The important components were variation in natality, summer mortality, and winter-spring disappearance. Investigation of the density relationships ofthe mortalities revealed possible density dependence in the variation in natality. Two very different types of population dynamics were evident. Populations in paspalum pastures were relatively stable, but in ryegrass pastures large population decreases between autumn and spring suggested that these pastures are favourable habitats during spring and summer only. Examination of the possible components of population mortalities revealed significant relationships between key mortalities and the level of population development. Evidence for the role of soil temperature and moisture levels, disease, adult migration, and combat mortality in influencing population change is presented.

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