... (Apis mellifera) in Tongariro National Park Claire Murphy and Alastair Robertson ... Figure 5... more ... (Apis mellifera) in Tongariro National Park Claire Murphy and Alastair Robertson ... Figure 5. Nectar standing crops in flax (mean ± standard error) expressed as milligrams sugar equivalents at seven study sites in Tongariro National Park (see Fig. 2 for site details). ...
A bioassay tested how long after application that residual herbicides used in forestry continue t... more A bioassay tested how long after application that residual herbicides used in forestry continue to suppress or kill broom (Cytisus scoparius) seedlings. Eleven herbicide treatments were applied to small plots of Tokomaru silt loam soil near Palmerston North on 4 December 2008. Soil samples were taken fortnightly until herbicide residues no longer affected broom seedlings. The samples were placed into pots and sown with scarified viable broom seeds within a heated glasshouse. Herbicide effects were determined by scoring the severity of damage to seedlings and measuring seedling dry weight; these were compared with broom seedlings established at the same time in untreated soil. The most persistent residues came from triclopyr/picloram applications, which killed broom seedlings for 5 months after application, and then suppressed growth of seedlings for a further 7 months. Broom seedling death also continued for 4-5 months for hexazinone application, for 2 months with clopyralid and ter...
Broom (Cytisus scoparius (L.) Link) is an invasive weed in many commercial radiata pine (Pinus ra... more Broom (Cytisus scoparius (L.) Link) is an invasive weed in many commercial radiata pine (Pinus radiata D.Don) plantations throughout New Zealand. As broom competes strongly with newly planted pine seedlings and has an abundant seed bank that persists longer than the forest rotation cycle, ongoing broom control is essential to prevent significant loss of production. A variety of herbicides are available to selectively control the established broom seedlings during the first year after planting pines but there is little published information describing which are saf-est for pines and most effective as the broom grows older. In this study, we evaluated the efficacy of six selective herbicides: (1) 450/300 g a.i. ha í1 clopyralid/ picloram, (2) 1500/300 g a.i. ha í1 clopyralid/triclopyr, (3) 1500/50/4/150 g a.i. ha í1 clopyralid/picloram/ triclopyr/aminopyralid, (4) 500 g a.i. ha í1 fluroxypyr, (5) 10 kg a.i. ha í1 terbuthylazine, and (6) 6 kg a.i. ha í1 hexazinone, applied at three rat...
Interactions between species are especially sensitive to environmental changes. The interaction b... more Interactions between species are especially sensitive to environmental changes. The interaction between plants and pollinators is of particular interest given the potential current global decline in pollinators. Reduced pollinator services can be compensated for in some plant species by self-pollination. However, if inbreeding depression is high, selfed progeny could die prior to reaching adulthood, leading to cryptic recruitment failure. To examine this scenario, pollinator abundance, pollen limitation, selfing rates and inbreeding depression were examined in 12 populations of varying disturbance levels in Sophora microphylla (Fabaceae), an endemic New Zealand tree species. High pollen limitation was found in all populations (average of 58 % reduction in seed production, nine populations), together with high selfing rates (61 % of offspring selfed, six populations) and high inbreeding depression (selfed offspring 86 % less fit, six populations). Pollen limitation was associated with lower visitation rates by the two endemic bird pollinators. The results suggest that for these populations, over half of the seeds produced are genetically doomed. This reduction in the fitness of progeny due to reduced pollinator service is probably important to population dynamics of other New Zealand species. More broadly, the results suggest that measures of seed production or seedling densities may be a gross overestimate of the effective offspring production. This could lead to cryptic recruitment failure, i.e. a decline in successful reproduction despite high progeny production. Given the global extent of pollinator declines, cryptic recruitment failure may be widespread.
Worldwide declines in bird numbers have recently renewed interest in how well bird-plant mutualis... more Worldwide declines in bird numbers have recently renewed interest in how well bird-plant mutualisms are functioning. In New Zealand, it has been argued that bird pollination was relatively unimportant and bird- pollination failure was unlikely to threaten any New Zealand plants, whereas dispersal mutualisms were widespread and in some cases potentially at risk because of reliance on a single large
... (Apis mellifera) in Tongariro National Park Claire Murphy and Alastair Robertson ... Figure 5... more ... (Apis mellifera) in Tongariro National Park Claire Murphy and Alastair Robertson ... Figure 5. Nectar standing crops in flax (mean ± standard error) expressed as milligrams sugar equivalents at seven study sites in Tongariro National Park (see Fig. 2 for site details). ...
A bioassay tested how long after application that residual herbicides used in forestry continue t... more A bioassay tested how long after application that residual herbicides used in forestry continue to suppress or kill broom (Cytisus scoparius) seedlings. Eleven herbicide treatments were applied to small plots of Tokomaru silt loam soil near Palmerston North on 4 December 2008. Soil samples were taken fortnightly until herbicide residues no longer affected broom seedlings. The samples were placed into pots and sown with scarified viable broom seeds within a heated glasshouse. Herbicide effects were determined by scoring the severity of damage to seedlings and measuring seedling dry weight; these were compared with broom seedlings established at the same time in untreated soil. The most persistent residues came from triclopyr/picloram applications, which killed broom seedlings for 5 months after application, and then suppressed growth of seedlings for a further 7 months. Broom seedling death also continued for 4-5 months for hexazinone application, for 2 months with clopyralid and ter...
Broom (Cytisus scoparius (L.) Link) is an invasive weed in many commercial radiata pine (Pinus ra... more Broom (Cytisus scoparius (L.) Link) is an invasive weed in many commercial radiata pine (Pinus radiata D.Don) plantations throughout New Zealand. As broom competes strongly with newly planted pine seedlings and has an abundant seed bank that persists longer than the forest rotation cycle, ongoing broom control is essential to prevent significant loss of production. A variety of herbicides are available to selectively control the established broom seedlings during the first year after planting pines but there is little published information describing which are saf-est for pines and most effective as the broom grows older. In this study, we evaluated the efficacy of six selective herbicides: (1) 450/300 g a.i. ha í1 clopyralid/ picloram, (2) 1500/300 g a.i. ha í1 clopyralid/triclopyr, (3) 1500/50/4/150 g a.i. ha í1 clopyralid/picloram/ triclopyr/aminopyralid, (4) 500 g a.i. ha í1 fluroxypyr, (5) 10 kg a.i. ha í1 terbuthylazine, and (6) 6 kg a.i. ha í1 hexazinone, applied at three rat...
Interactions between species are especially sensitive to environmental changes. The interaction b... more Interactions between species are especially sensitive to environmental changes. The interaction between plants and pollinators is of particular interest given the potential current global decline in pollinators. Reduced pollinator services can be compensated for in some plant species by self-pollination. However, if inbreeding depression is high, selfed progeny could die prior to reaching adulthood, leading to cryptic recruitment failure. To examine this scenario, pollinator abundance, pollen limitation, selfing rates and inbreeding depression were examined in 12 populations of varying disturbance levels in Sophora microphylla (Fabaceae), an endemic New Zealand tree species. High pollen limitation was found in all populations (average of 58 % reduction in seed production, nine populations), together with high selfing rates (61 % of offspring selfed, six populations) and high inbreeding depression (selfed offspring 86 % less fit, six populations). Pollen limitation was associated with lower visitation rates by the two endemic bird pollinators. The results suggest that for these populations, over half of the seeds produced are genetically doomed. This reduction in the fitness of progeny due to reduced pollinator service is probably important to population dynamics of other New Zealand species. More broadly, the results suggest that measures of seed production or seedling densities may be a gross overestimate of the effective offspring production. This could lead to cryptic recruitment failure, i.e. a decline in successful reproduction despite high progeny production. Given the global extent of pollinator declines, cryptic recruitment failure may be widespread.
Worldwide declines in bird numbers have recently renewed interest in how well bird-plant mutualis... more Worldwide declines in bird numbers have recently renewed interest in how well bird-plant mutualisms are functioning. In New Zealand, it has been argued that bird pollination was relatively unimportant and bird- pollination failure was unlikely to threaten any New Zealand plants, whereas dispersal mutualisms were widespread and in some cases potentially at risk because of reliance on a single large
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