title: The Potential for Re-Invasion by Mammalian Pests at Maungatautari Ecological Island

authors: Connolly, Trevor Allan

subjects: Maungatautari

abstract: Mammalian pests are excluded from Maungatautari Ecological Island by an XcluderTM pest-proof fence. Inevitably, the fence integrity will be compromised at some point by mechanisms such as treefall and flood-scour: such events could lead to pest re-invasion. Knowledge of pest activity directly outside the reserve would assist reserve managers in developing optimal breach-response procedures. This thesis described baseline data on the presence, timing of activity and behaviour of mammalian pest animals found directly at the Maungatautari fence. Two seasonal video studies investigated the effects of season (summer and winter), exterior habitat (forest and pasture) and simulated breach type ('tree-fall' and 'flood scour') on the number of pest sightings. Significantly more sightings were recorded in summer (788) than in winter (428), particularly for rodents. Rabbits were sighted significantly more often at pasture sites, but habitat type did not significantly affect sightings of any other species; nor did breach type affect sightings of any species. Ship rats were commonly sighted within the fence hood gutter. Overall, rodent, possum and cat sightings were very high, and mustelid sightings extremely low, in both seasons. Over 95% of non-lagomorph sightings were nocturnal, and the greatest threat of invasion was found to come nocturnally, from mice, and in the summer. A probability model showed that although the cumulative probability of a mammalian pest encountering a fence breach increases dramatically after dark, in reality there is always a threat of encounter, and this is always increasing with time. Over the same two studies, the behaviour of pest mammals sighted was also described. Pests were found to show interest in and enter summer breaches more often than winter breaches (p lt 0.001). Simulated breaches were encountered by pests within the first 24 hours at a very high rate (95% summer, 92.5% winter), and most likely to enter a breach were rodents. Over 7 days, breaches were encountered and entered by increasing numbers of species and possibly by more individuals; all species were shown to be willing to enter. The threat of invasion by ship rats was probably underestimated because of their higher activity within the fence hood than at the fence base; mustelids may also offer a greater threat than the results suggest, because they almost always entered a breach. It was strongly recommended that when the fence integrity is compromised, physical response should be as quick as possible, especially at night. Future research was strongly encouraged, particularly to understand invasion behaviour of animals such as ship rats and stoats, and to describe pest behaviour at real breach events.

text: The Potential for Re-Invasion by Mammalian Pests at Maungatautari Ecological Island Mammalian pests are excluded from Maungatautari Ecological Island by an XcluderTM pest-proof fence. Inevitably, the fence integrity will be compromised at some point by mechanisms such as treefall and flood-scour: such events could lead to pest re-invasion. Knowledge of pest activity directly outside the reserve would assist reserve managers in developing optimal breach-response procedures. This thesis described baseline data on the presence, timing of activity and behaviour of mammalian pest animals found directly at the Maungatautari fence. Two seasonal video studies investigated the effects of season (summer and winter), exterior habitat (forest and pasture) and simulated breach type ('tree-fall' and 'flood scour') on the number of pest sightings. Significantly more sightings were recorded in summer (788) than in winter (428), particularly for rodents. Rabbits were sighted significantly more often at pasture sites, but habitat type did not significantly affect sightings of any other species; nor did breach type affect sightings of any species. Ship rats were commonly sighted within the fence hood gutter. Overall, rodent, possum and cat sightings were very high, and mustelid sightings extremely low, in both seasons. Over 95% of non-lagomorph sightings were nocturnal, and the greatest threat of invasion was found to come nocturnally, from mice, and in the summer. A probability model showed that although the cumulative probability of a mammalian pest encountering a fence breach increases dramatically after dark, in reality there is always a threat of encounter, and this is always increasing with time. Over the same two studies, the behaviour of pest mammals sighted was also described. Pests were found to show interest in and enter summer breaches more often than winter breaches (p lt 0.001). Simulated breaches were encountered by pests within the first 24 hours at a very high rate (95% summer, 92.5% winter), and most likely to enter a breach were rodents. Over 7 days, breaches were encountered and entered by increasing numbers of species and possibly by more individuals; all species were shown to be willing to enter. The threat of invasion by ship rats was probably underestimated because of their higher activity within the fence hood than at the fence base; mustelids may also offer a greater threat than the results suggest, because they almost always entered a breach. It was strongly recommended that when the fence integrity is compromised, physical response should be as quick as possible, especially at night. Future research was strongly encouraged, particularly to understand invasion behaviour of animals such as ship rats and stoats, and to describe pest behaviour at real breach events.

year: 2008

title: Publishing panel: Book proposals and environmental history journals

authors: Beattie, James John

abstract: This presentation was associated with the conference held at Macquarie University, 'Foreign Bodies, Intimate Ecologies: Transformations in Environmental History' (10-13 February 2016), at which James Beattie presented a paper entitled, ' "Hungry dragons" in the South Pacific: Chinese resource frontiers, environmental change, and entrepreneurship'

text: Publishing panel: Book proposals and environmental history journals This presentation was associated with the conference held at Macquarie University, 'Foreign Bodies, Intimate Ecologies: Transformations in Environmental History' (10-13 February 2016), at which James Beattie presented a paper entitled, ' "Hungry dragons" in the South Pacific: Chinese resource frontiers, environmental change, and entrepreneurship'

year: 2016

title: Comparative fish abundance in the shallow Waikato lakes Whangape and Hakanoa

authors: Hicks, Brendan J.

abstract: The Waikato-Tainui College for Research and Development contracted the University of Waikato to conduct boat electrofishing estimates of the fish abundance in lakes Whangape and Hakanoa; both are shallow, riverine lakes in the lower Waikato River floodplain and are about 2,000 years old. Lake Whangape (latitude 37.46853°S, longitude 175.05120°W) is a large (1,450 ha), shallow (maximum depth 2.7 m) lake to the west of the Waikato River; Lake Hakanoa (latitude 37.55258°S, longitude 175.16859°W) is a 52-ha lake in suburban Huntly with a maximum depth of 2.5 m.
We fished 10 sites for 10 mins in both lakes Whangape and Lake Hakanoa; sites fished were 253-609 m long (1,012-2,436 m² in area) in Lake Whangape and 125-276 m long (500-1,104 m² in area) in Lake Hakanoa.
No submerged aquatic macrophytes were seen in either lake. Fishing was conducted close to the water's edge in Lake Hakanoa, but the shallow margins in Lake Whangape restricted fishing at most sites to 30-70 m from the shoreline. The shoreline was much more accessible in Lake Hakanoa, and was dominated by raupo (Typha orientalis) with willows (Salix spp.) in places. Submerged tree trunks and logs in Lake Hakanoa made navigation difficult in parts of the lake margins.
We caught a total of 118 fish in Lake Whangape, where shortfin eels (Anguilla australis) were the most abundant fish, and 594 fish in Lake Hakanoa, where gambusia (Gambusia affinis) the most abundant species. In Lake Whangape, shortfin eels comprised the greatest total biomass (12.4 kg), with koi carp (Cyprinus carpio) almost equally abundant (11.4 kg). In Lake Hakanoa, koi carp were most abundant (74.4 kg), followed by shortfin eels (22.1 kg).
Fish were unevenly spread among sites in Lake Whangape and koi carp were relatively sparsely among sites. In Lake Hakanoa, in contrast, fish were more evenly spread among sites, but with higher concentrations of catfish (Ameiurus nebulosus) and goldfish (Carassius auratus) at a few sites. Biomass of fish caught in each of the ten 10-min fishing shots reflected the numerical distributions, with some wide variations between sites. Fish densities were generally lower in Lake Whangape than in Lake Hakanoa; however, common smelt (Retropinna retropinna) and grey mullet (Mugil cephalus) occurred in Whangape but not in Hakanoa. Areal fish biomass was dominated by shortfin eels and koi carp in Lake Whangape, but koi carp dominated the fish biomass in Lake Hakanoa, despite the smaller number of carp than eels. This was because of the large mean weight of koi carp (about 1,000 g) compared to the smaller shortfin eels (mean weight about 200 g in both lakes).

text: Comparative fish abundance in the shallow Waikato lakes Whangape and Hakanoa The Waikato-Tainui College for Research and Development contracted the University of Waikato to conduct boat electrofishing estimates of the fish abundance in lakes Whangape and Hakanoa; both are shallow, riverine lakes in the lower Waikato River floodplain and are about 2,000 years old. Lake Whangape (latitude 37.46853°S, longitude 175.05120°W) is a large (1,450 ha), shallow (maximum depth 2.7 m) lake to the west of the Waikato River; Lake Hakanoa (latitude 37.55258°S, longitude 175.16859°W) is a 52-ha lake in suburban Huntly with a maximum depth of 2.5 m.
We fished 10 sites for 10 mins in both lakes Whangape and Lake Hakanoa; sites fished were 253-609 m long (1,012-2,436 m² in area) in Lake Whangape and 125-276 m long (500-1,104 m² in area) in Lake Hakanoa.
No submerged aquatic macrophytes were seen in either lake. Fishing was conducted close to the water's edge in Lake Hakanoa, but the shallow margins in Lake Whangape restricted fishing at most sites to 30-70 m from the shoreline. The shoreline was much more accessible in Lake Hakanoa, and was dominated by raupo (Typha orientalis) with willows (Salix spp.) in places. Submerged tree trunks and logs in Lake Hakanoa made navigation difficult in parts of the lake margins.
We caught a total of 118 fish in Lake Whangape, where shortfin eels (Anguilla australis) were the most abundant fish, and 594 fish in Lake Hakanoa, where gambusia (Gambusia affinis) the most abundant species. In Lake Whangape, shortfin eels comprised the greatest total biomass (12.4 kg), with koi carp (Cyprinus carpio) almost equally abundant (11.4 kg). In Lake Hakanoa, koi carp were most abundant (74.4 kg), followed by shortfin eels (22.1 kg).
Fish were unevenly spread among sites in Lake Whangape and koi carp were relatively sparsely among sites. In Lake Hakanoa, in contrast, fish were more evenly spread among sites, but with higher concentrations of catfish (Ameiurus nebulosus) and goldfish (Carassius auratus) at a few sites. Biomass of fish caught in each of the ten 10-min fishing shots reflected the numerical distributions, with some wide variations between sites. Fish densities were generally lower in Lake Whangape than in Lake Hakanoa; however, common smelt (Retropinna retropinna) and grey mullet (Mugil cephalus) occurred in Whangape but not in Hakanoa. Areal fish biomass was dominated by shortfin eels and koi carp in Lake Whangape, but koi carp dominated the fish biomass in Lake Hakanoa, despite the smaller number of carp than eels. This was because of the large mean weight of koi carp (about 1,000 g) compared to the smaller shortfin eels (mean weight about 200 g in both lakes).

year: 2016