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The home range, activity and habitat use of wild European rabbits in northern South Australia were compared during winter and summer, and results used to suggest improvements to control techniques. Average home range was significantly smaller in summer (2.1 ha) than winter (4.2 ha) and there was no significant difference between the sexes. Rabbits used both dune and swale habitat but most warrens and more surface fixes were recorded in dune habitat in both seasons. Proportionally more surface fixes were found in swale habitat at night than during the day. The proportion of diurnal fixes on the surface was not significantly influenced by season, averaging 47% in winter and 62% in summer. Only 30% of radio-collared rabbits flushed by humans retreated to warrens. Comparable levels of diurnal surface activity in both winter and summer suggest that the death rate from fumigation or warren destruction may be similar in both seasons. High levels of diurnal surface activity suggest that warren fumigation may be ineffective unless rabbits can first be flushed to their warrens. The use of dogs to flush rabbits before fumigation or ripping should increase the efficacy of control. Activity data suggest that fumigation or ripping should be conducted between 0900 and 1600 hours in winter and 1100 and 1800 hours in summer when radio-collared rabbits were most likely to be down their warrens. Home-range data suggest that the effectiveness of poison baiting may be increased by placing bait lines closer together in summer and, although bait lines should be concentrated in dune habitat, some poison should also be placed in swale feeding areas remote from warrens. The most successful control method for radio-collared rabbits was fumigation with phosphine gas tablets, with 10 of 11 rabbits successfully killed. Pressure fumigation with chloropicrin was also successful but 1080 poisoning and warren destruction using shovels were all relatively unsuccessful.

Degradation of organic matter (OM) is generally considered to be primarily governed by biotic factors in aquatic environments. However, a number of abiotic processes also play key roles in mediating OM-degradation. Sunlight can act as a principal abiotic driver of the degradation of terrestrial organic matter, but its importance for freshwater ecosystems and possible interactions with biotic drivers remains poorly understood. We carried out two microcosm experiments which focused on the role of sunlight on microbial and invertebrate-mediated OM degradation using two species of plant leaves and the aquatic invertebrate Asellus aquaticus. Results indicated that sunlight was the primary driver of leaf mass loss during the early stages of decomposition, whereas microbial communities had a negligible effect. Sunlight was observed to strongly affect invertebrate behavior as invertebrates avoided direct illumination. This alteration of behavior resulted in a reduction in the consumption of a leaf surrogate (DECOTAB) by A. aquaticus. Together, these results indicate that sunlight has the potential to strongly influence structural and functional attributes of shallow freshwater systems, and hence serve as an appraisal to consider sunlight as a significant direct and indirect physical driver governing OM degradation in shallow aquatic systems.

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