title: Extent estimates and land cover relationships for functional indicators in non-wadeable rivers

authors: Collier, Kevin J.

subjects: metabolism

abstract: Functional indicators are being increasingly used to assess waterway health but their responses to pressure in non-wadeable rivers have not been widely documented or applied in modern survey designs that provide unbiased estimates of extent. This study tests the response of river metabolism and loss in cotton strip tensile strength across a land use pressure gradient in non-wadeable rivers of northern New Zealand, and reports extent estimates for river metabolism and decomposition rates. Following adjustment for probability of selection, ecosystem respiration (ER) and gross primary production (GPP) for the target population of order 5–7 non-wadeable rivers averaged −7.3 and 4.8 g O2 mˉ² dˉ¹, respectively, with average P/R < 1 indicating dominance by heterotrophic processes. Ecosystem respiration was <−3.3 g O2 mˉ² dˉ¹ for 75% of non-wadeable river length with around 20% of length between −10 and −20 g O2 mˉ² dˉ¹. Cumulative distribution functions of cotton strength loss estimates indicated a more-or-less linear relationship with river km reflecting an even spread of decay rates (range in k 0.0007–0.2875 dˉ¹) across non-wadeable rivers regionally. A non-linear relationship with land cover was detected for GPP which was typically <5 g O2 mˉ² dˉ¹ where natural vegetation cover was below 20% and greater than 80% of upstream catchment area. For cotton strength loss, the relationship with land cover was wedge-shaped such that sites with >60% natural cover had low decay rates (<0.02 dˉ¹) with variability below this increasing as natural cover declined. Using published criteria for assessing waterway health based on ER and GPP, 232–298 km (20–29%) of non-wadeable river length was considered to have severely impaired ecosystem functioning, and 436–530 km (42–50%) had no evidence of impact on river metabolism.

text: Extent estimates and land cover relationships for functional indicators in non-wadeable rivers Functional indicators are being increasingly used to assess waterway health but their responses to pressure in non-wadeable rivers have not been widely documented or applied in modern survey designs that provide unbiased estimates of extent. This study tests the response of river metabolism and loss in cotton strip tensile strength across a land use pressure gradient in non-wadeable rivers of northern New Zealand, and reports extent estimates for river metabolism and decomposition rates. Following adjustment for probability of selection, ecosystem respiration (ER) and gross primary production (GPP) for the target population of order 5–7 non-wadeable rivers averaged −7.3 and 4.8 g O2 mˉ² dˉ¹, respectively, with average P/R < 1 indicating dominance by heterotrophic processes. Ecosystem respiration was <−3.3 g O2 mˉ² dˉ¹ for 75% of non-wadeable river length with around 20% of length between −10 and −20 g O2 mˉ² dˉ¹. Cumulative distribution functions of cotton strength loss estimates indicated a more-or-less linear relationship with river km reflecting an even spread of decay rates (range in k 0.0007–0.2875 dˉ¹) across non-wadeable rivers regionally. A non-linear relationship with land cover was detected for GPP which was typically <5 g O2 mˉ² dˉ¹ where natural vegetation cover was below 20% and greater than 80% of upstream catchment area. For cotton strength loss, the relationship with land cover was wedge-shaped such that sites with >60% natural cover had low decay rates (<0.02 dˉ¹) with variability below this increasing as natural cover declined. Using published criteria for assessing waterway health based on ER and GPP, 232–298 km (20–29%) of non-wadeable river length was considered to have severely impaired ecosystem functioning, and 436–530 km (42–50%) had no evidence of impact on river metabolism.

year: 2013

title: Determining and testing the optimal pure-tone frequency for use in acoustic conditioning of free-ranging common carp (Cyprinus carpio)

authors: Mahoney, Brennan Andrew

subjects: carp

abstract: Pure-tone frequencies of 400, 700, and 1000 Hz were tested to determine which achieved the strongest response when used in conditioning experiments on captive common carp (Cyprinus carpio) for the purpose of determining the most effective frequency to use in conditioning experiments on free-ranging common carp. Captive common carp were shown to have the strongest response to the 400 Hz frequency after training that associated sound with food. Response was quantified as moving into a feeding arena when the sound was broadcast, and all frequencies achieved conditioning within five days. Secondly, the attenuation of the three frequencies were compared in a Waikato lake (Lake Kaituna) containing common carp. The ability to maintain signal strength over distance is necessary for frequencies used in the acoustic conditioning of free-ranging common carp due to the potentially large distances involved. Attenuation of the 400 Hz and 700 Hz pure tone frequencies were not significantly different but were both lower than that of the 1000 Hz frequency. The 400 Hz pure tone frequency was used in subsequent experiments on the acoustic conditioning of free-ranging common carp in Lake Kaituna because of superior performance in acoustic conditioning of captive common carp and low attenuation in a natural water body containing free-ranging common carp,. Thirdly, the 400 Hz pure tone was evaluated for its ability to be associated with food by free-ranging common carp. Capture rates at treatment sites where 400 Hz pure tone was broadcast compared to control sites where no sound was broadcast following a five-day training phase and 24 h of no sound or food, were 2.1 times greater during a three-day capture phase. This study demonstrates the trainability of common carp, a trait that can be used to improve control of wild common carp populations.

text: Determining and testing the optimal pure-tone frequency for use in acoustic conditioning of free-ranging common carp (Cyprinus carpio) Pure-tone frequencies of 400, 700, and 1000 Hz were tested to determine which achieved the strongest response when used in conditioning experiments on captive common carp (Cyprinus carpio) for the purpose of determining the most effective frequency to use in conditioning experiments on free-ranging common carp. Captive common carp were shown to have the strongest response to the 400 Hz frequency after training that associated sound with food. Response was quantified as moving into a feeding arena when the sound was broadcast, and all frequencies achieved conditioning within five days. Secondly, the attenuation of the three frequencies were compared in a Waikato lake (Lake Kaituna) containing common carp. The ability to maintain signal strength over distance is necessary for frequencies used in the acoustic conditioning of free-ranging common carp due to the potentially large distances involved. Attenuation of the 400 Hz and 700 Hz pure tone frequencies were not significantly different but were both lower than that of the 1000 Hz frequency. The 400 Hz pure tone frequency was used in subsequent experiments on the acoustic conditioning of free-ranging common carp in Lake Kaituna because of superior performance in acoustic conditioning of captive common carp and low attenuation in a natural water body containing free-ranging common carp,. Thirdly, the 400 Hz pure tone was evaluated for its ability to be associated with food by free-ranging common carp. Capture rates at treatment sites where 400 Hz pure tone was broadcast compared to control sites where no sound was broadcast following a five-day training phase and 24 h of no sound or food, were 2.1 times greater during a three-day capture phase. This study demonstrates the trainability of common carp, a trait that can be used to improve control of wild common carp populations.

year: 2012

title: Kia reo Māori anahe te reo karanga

authors: Puke, Haupai

subjects: Karanga

abstract: Mā taku karanga o runga ake nei tēnei tuhinga e wāwāhi. Ahakoa he aha te ahurea ōna tikanga me ōna kawa, kua hurihia i roto i ngā rautau. Ko ngētehi kei te pupuruhia tonutia hāunga anō he hou ōna āhuatanga. Ko te kaupapa rangahau o tēnei tuhinga ko te karanga me ngētehi āhuatanga ōna hei tautoko i te whakahau kia noho reo Māori anahe te reo karanga. He aha e pēnei na ai te whakaaro mō tēnei o ngā tikanga o te ao Māori? I runga anō i ngā āhuatanga hou, i ngā whakarerekētanga tikanga o te karanga i roto i tēnei ao hurihuri kāore e tautāwhina te take. Ko ngā kōrero, ngā whakaaro hoki e whai ake nei e wānangahia ai hei tautoko i tēnei whakapae āku.

text: Kia reo Māori anahe te reo karanga Mā taku karanga o runga ake nei tēnei tuhinga e wāwāhi. Ahakoa he aha te ahurea ōna tikanga me ōna kawa, kua hurihia i roto i ngā rautau. Ko ngētehi kei te pupuruhia tonutia hāunga anō he hou ōna āhuatanga. Ko te kaupapa rangahau o tēnei tuhinga ko te karanga me ngētehi āhuatanga ōna hei tautoko i te whakahau kia noho reo Māori anahe te reo karanga. He aha e pēnei na ai te whakaaro mō tēnei o ngā tikanga o te ao Māori? I runga anō i ngā āhuatanga hou, i ngā whakarerekētanga tikanga o te karanga i roto i tēnei ao hurihuri kāore e tautāwhina te take. Ko ngā kōrero, ngā whakaaro hoki e whai ake nei e wānangahia ai hei tautoko i tēnei whakapae āku.

year: 2012-05