The number of Vespula wasp workers in a colony can be predicted from the mean of !-minute counts of wasps entering or leaving the colony (traffic rate). The predictive equation (Adjusted R 2 = 0.87) is: number of workers= 32.243 X traffic rate per minute and is independent of species, time of year, or location. However, we mainly measured mature colonies. The equation may overestimate the number of workers in spring colonies, because a greater proportion of workers forage then. Traffic rate can also predict the biomass of a V. vulgaris colony (Adjusted R 2 = 0.90) by allowing for season. Colonies measured after mid May generally had a larger biomass for any given traffic rate than those measured earlier. There were too few data from V. germanica colonies to evaluate the relationship between traffic r~ and biomass for this species.
Recreational hunters are concerned that aerial 1080 operations in New Zealand's forests may adversely affect deer hunting, but data are rarely gathered in a way that enables such effects to be assessed. Between 2011 and 2015, we recorded two relevant indicators of the recreational hunting experience -number of red deer (Cervus elaphus) encounters, and number of individual red deer seen -in 865 person days of quarterly surveys across seven blocks of native forest in South Westland, New Zealand. Four blocks were treated with aerial 1080 before and during the study, and three were untreated. Generalised linear mixed effects models provide no evidence that aerial 1080 treatments reduced numbers of red deer encounters or numbers of individual red deer seen over time. There were no overall trends in numbers of deer encounters and deer seen per person day in either treated or untreated blocks over the study period, and average numbers of deer encounters and deer seen in treated and untreated blocks were similar. Models fitted to data from the 1080-treated forest blocks alone showed that numbers of deer encounters and numbers of deer seen per person day were highest in the period immediately following an aerial 1080 operation and declined over the following 2-3 years. This pattern is likely to result from a change in deer behaviour rather than in deer numbers, and its cause is unknown.
The introduction of mammalian predators, particularly stoats (Mustela erminea), to New Zealand led to the decline in whio (Hymenolaimus malacorhynchos), an endemic riverine duck. Stoat control for whio in the South Island has focused on valley floor trapping along waterway margins but increasing survival and productivity for whio using this method is complicated by irruptive predator dynamics caused by occasional masting of beech species (Nothofagaceae). We investigated the effect of integrating stoat trapping with pulsed aerial 1080 toxin operations to counter predator irruptions on whio survival and productivity in c. 40 000 ha of beech dominated Kahurangi National Park. We collected data on adult female whio survival, probability of breeding, nesting success, and duckling survival for seven years through two full beech mast events. We found a positive relationship between distance into the interior of the treatment block and whio population growth, nesting success, duckling, and adult survival. Heavy female whio were more likely to breed than light ones, and adult female survival was higher during the breeding season than during non-breeding. Nesting success was greatest in the breeding season following a 1080 operation. Duckling survival was higher at lower river flows. Positive population growth was only predicted near the centre of the study area (c. 13 km from the edge) with both traps and 1080. We conclude that in the centre of treatment blocks at least as large as our study block, integrated pest control should be enough to ensure long-term population persistence of whio in a beech-dominated system.
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