O’Donnell, C. F. J. 2001. Home range and use of space by Chalinolobus tuberculatus, a temperate rainforest bat from New Zealand. Journal of Zoology (London) 253: 253–264.
Home range sizes in long-tailed bats were among the largest published for Microchiroptera. These bats were highly mobile. One colony ranged over 100 km² and range size varied among age and sex classes (medians = 237–2,006 ha; max 5629 ha). A prediction that these bats have large ranges to minimise overlap between foraging bats, reflecting scarcity of food, requires testing. Large range size and the degree of individual spacing implies that conservation areas designed for bats should be large.
02 December, 2001
Kelly et al. (2001): Evaluating the wind-pollination benefits of mast seeding.
Kelly, D., Hart, D.E. & Allen, R.B. 2001. Evaluating the wind-pollination benefits of mast seeding. Ecology 82: 117-126.
A model for when plants gain pollination benefits from mast seeding shows that the greatest benefits go to species with low pollination success at the long term mean flowering effort. Tests of this model in Chionochloa, Nothofagus, Dacrydium and Betula alleghaniensis show a range of benefits from trivial in Chionochloa to very strong in N. solandri. This suggests that the pronounced masting seen in Nothofagus is attributable to pollination efficiencies. The model also explains the stronger masting seen at higher elevation sites, and predicts that habitat fragmentation could disrupt mast seeding benefits to pollination.
A model for when plants gain pollination benefits from mast seeding shows that the greatest benefits go to species with low pollination success at the long term mean flowering effort. Tests of this model in Chionochloa, Nothofagus, Dacrydium and Betula alleghaniensis show a range of benefits from trivial in Chionochloa to very strong in N. solandri. This suggests that the pronounced masting seen in Nothofagus is attributable to pollination efficiencies. The model also explains the stronger masting seen at higher elevation sites, and predicts that habitat fragmentation could disrupt mast seeding benefits to pollination.
Keedwell (2001): Evaluation of radio transmitters for measuring chick mortality in the banded dotterel.
Keedwell, R. 2001. Evaluation of radio transmitters for measuring chick mortality in the banded dotterel. Waterbirds 24: 217–223.
Details the results of a trial using elastic harnesses to attach radio transmitters to banded dotterel chicks in order to determine rates and causes of mortality. The technique only had limited application to young chicks because the harness occasionally fell off or entangled small chicks but the transmitters remained attached to chicks older than one week. Most mortality occurred in the first week, and predators were responsible for a minimum of 18% of deaths.
Details the results of a trial using elastic harnesses to attach radio transmitters to banded dotterel chicks in order to determine rates and causes of mortality. The technique only had limited application to young chicks because the harness occasionally fell off or entangled small chicks but the transmitters remained attached to chicks older than one week. Most mortality occurred in the first week, and predators were responsible for a minimum of 18% of deaths.
Wells et al. (2001): Forest dynamics in Westland, New Zealand: the importance of large, infrequent earthquake-induced disturbance.
Wells, A.; Duncan, R.P.; Stewart, G.H. 2001. Forest dynamics in Westland, New Zealand: the importance of large, infrequent earthquake-induced disturbance. Journal of Ecology 89: 1006-1018.
A reconstruction of forest disturbance history in a Westland catchment over the last 700 years reveals that, during this period, the catchment was affected by four massive episodes of landslipping and flooding, with up to 50% of the forested area of the catchment destroyed in a single episode. These episodes dominate the disturbance regime and were triggered by earthquakes, the three largest (dated c. 1460, 1620 and 1717 AD) caused by the last three major movements of the Alpine Fault. Much of the present forest structure in Westland reflects the impact of these major earthquakes.
A reconstruction of forest disturbance history in a Westland catchment over the last 700 years reveals that, during this period, the catchment was affected by four massive episodes of landslipping and flooding, with up to 50% of the forested area of the catchment destroyed in a single episode. These episodes dominate the disturbance regime and were triggered by earthquakes, the three largest (dated c. 1460, 1620 and 1717 AD) caused by the last three major movements of the Alpine Fault. Much of the present forest structure in Westland reflects the impact of these major earthquakes.
Wardle et al. (2001): Introduced browsing mammals in natural New Zealand forests: aboveground and belowground consequences.
Wardle, D. A.; Barker, G. M.; Yeates, G. W.; Bonner, K. I.; Ghani, A. 2001. Introduced browsing mammals in natural New Zealand forests: aboveground and belowground consequences. Ecological Monographs 71: 587–614.
The effects of browsing mammals (deer and goats) on plant and soil microbial and invertebrate communities was assessed for each of 30 long term exclosure plots in forests located throughout New Zealand. While browse layer vegetation density and diver-sity was consistently adversely affected by herbivores, the soil biota showed varied responses, and only invertebrates with larger body sizes were consistently adversely affected. There were also several instances in which browsers affected decomposer diversity, key soil processes and soil carbon and nitrogen sequestration. Frequently below-ground effects of these mammals were more severe than we would predict based on the response of vegetation.
The effects of browsing mammals (deer and goats) on plant and soil microbial and invertebrate communities was assessed for each of 30 long term exclosure plots in forests located throughout New Zealand. While browse layer vegetation density and diver-sity was consistently adversely affected by herbivores, the soil biota showed varied responses, and only invertebrates with larger body sizes were consistently adversely affected. There were also several instances in which browsers affected decomposer diversity, key soil processes and soil carbon and nitrogen sequestration. Frequently below-ground effects of these mammals were more severe than we would predict based on the response of vegetation.
Standish et al. (2001): The impact of an invasive weed Tradescantia fluminensis on native forest regeneration.
Standish, R.J.; Robertson, AW.; & Williams, P.A. 2001. The impact of an invasive weed Tradescantia fluminensis on native forest regeneration. Journal of Applied Ecology 38: 1253-1263.
A major effect of Tradescantia in forest is the suppression of seedlings. Data from two Manawatu/Horowhenua forest remnants showed that Tradescantia biomass reaches a maximum at edges and under canopy gaps. In these areas, Tradescantia biomass becomes so thick that very little light penetrates to the soil and almost all woody seedlings are suppressed. In shadier spots, the Tradescantia is not as thick, more light reaches the forest floor and more shade tolerant seedlings like kohekohe establish. These results suggest that imposing shade by establishing a subcanopy through planting may allow the natural regeneration cycle to be partly restored.
A major effect of Tradescantia in forest is the suppression of seedlings. Data from two Manawatu/Horowhenua forest remnants showed that Tradescantia biomass reaches a maximum at edges and under canopy gaps. In these areas, Tradescantia biomass becomes so thick that very little light penetrates to the soil and almost all woody seedlings are suppressed. In shadier spots, the Tradescantia is not as thick, more light reaches the forest floor and more shade tolerant seedlings like kohekohe establish. These results suggest that imposing shade by establishing a subcanopy through planting may allow the natural regeneration cycle to be partly restored.
Sinclair et al. (2001): Microhabitat selection and seasonality of alpine invertebrates.
Sinclair, B.J.; Lord, J.M.; Thompson, C.M. 2001. Microhabitat selection and seasonality of alpine invertebrates. Pedobiologia 45: 107-120.
This study examined the invertebrate fauna under rock slabs in summer and winter on Rock and Pillar Range, Otago. Rock size and season were the most important determinants of species presence. Species examined in detail were the cockroach Celatoblatta quinquemaculata, alpine weta Hemideina maori, and a spider Neoramia childi. We found evidence of positive interactions between weta and cockroach independent of rock size, but negative interactions between these species and spiders. The amount of vegetation around the rock was positively associated with cockroaches but negatively with weta. Adjacent vegetation composition had no effect.
This study examined the invertebrate fauna under rock slabs in summer and winter on Rock and Pillar Range, Otago. Rock size and season were the most important determinants of species presence. Species examined in detail were the cockroach Celatoblatta quinquemaculata, alpine weta Hemideina maori, and a spider Neoramia childi. We found evidence of positive interactions between weta and cockroach independent of rock size, but negative interactions between these species and spiders. The amount of vegetation around the rock was positively associated with cockroaches but negatively with weta. Adjacent vegetation composition had no effect.
Sinclair (2001): On the distribution of terrestrial invertebrates at Cape Bird, Ross Island, Antarctica.
Sinclair, B.J. 2001. On the distribution of terrestrial invertebrates at Cape Bird, Ross Island, Antarctica. Polar Biology 24: 394-400.
In this paper the terrestrial fauna of the Cape Bird Ice-Free Area is surveyed. Little relationship was found between the presence of macroscopic vegetation and invertebrates. This has important conservation implications, because many Antarctic protected areas are currently designated on the basis of vegetation, under the assumption that this preserves a representative terrestrial community, while this paper shows that this is not the case.
In this paper the terrestrial fauna of the Cape Bird Ice-Free Area is surveyed. Little relationship was found between the presence of macroscopic vegetation and invertebrates. This has important conservation implications, because many Antarctic protected areas are currently designated on the basis of vegetation, under the assumption that this preserves a representative terrestrial community, while this paper shows that this is not the case.
Sinclair (2001): Field ecology of freeze tolerance: the alpine cockroach Celatoblatta quinquemaculata.
Sinclair, B.J. 2001. Field ecology of freeze tolerance: interannual variation in cooling rates, freeze-thaw and thermal stress in the microhabitat of the alpine cockroach Celatoblatta quinquemaculata. Oikos 93: 286-293.
This paper takes laboratory data on the low temperature thermal biology of an alpine cockroach, and applies it to the interpretation of field microclimate data spanning 4 years. During the 1998 El Nino winter a lack of snow cover (and therefore insulation) resulted in much more extreme winter temperatures and many more freeze thaw events. This situation is used as an analogue for predicted climate change, and suggests that an alpine zone community may be maintained at low(ish) altitudes by severe frost events in this scenario.
This paper takes laboratory data on the low temperature thermal biology of an alpine cockroach, and applies it to the interpretation of field microclimate data spanning 4 years. During the 1998 El Nino winter a lack of snow cover (and therefore insulation) resulted in much more extreme winter temperatures and many more freeze thaw events. This situation is used as an analogue for predicted climate change, and suggests that an alpine zone community may be maintained at low(ish) altitudes by severe frost events in this scenario.
Sinclair (2001): Biologically relevant environmental data: Macros to make the most of microclimate recordings.
Sinclair, B.J. 2001. Biologically relevant environmental data: Macros to make the most of microclimate recordings. Cryo-Letters 22: 125-134.
Automated data loggers make it possible to gather vast quantities of environmental data, but the quantity can be overwhelming, limiting interpretation to means, rather than the biologically relevant thresholds. This paper presents macros for Microsoft Excel that calculate rates of change of a data series that has crossed a threshold; it will count the number of times a threshold is crossed (and allows for the decreasing threshold being different from the increasing threshold), and for calculating the amount of time that a threshold is exceeded. These macros are available electronically from the author bjs@sun.ac.za.
Automated data loggers make it possible to gather vast quantities of environmental data, but the quantity can be overwhelming, limiting interpretation to means, rather than the biologically relevant thresholds. This paper presents macros for Microsoft Excel that calculate rates of change of a data series that has crossed a threshold; it will count the number of times a threshold is crossed (and allows for the decreasing threshold being different from the increasing threshold), and for calculating the amount of time that a threshold is exceeded. These macros are available electronically from the author bjs@sun.ac.za.
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