title: The extrapolation of social landscape values to a national level in New Zealand using landscape character classification

authors: Brown, Greg

subjects: character

abstract: The human perception and valuation of landscapes is a complex process but has been pragmatically advanced through public participation GIS (PPGIS). PPGIS methods have the capacity to generate spatial data to empirically examine relationships between human landscape values and physical landscape character. In 2011, PPGIS methods were used to identify a range of social landscape values for two regions in southern New Zealand, Otago and Southland. Seven of these landscape values were analysed to identify significant relationships with physical landscape character from the New Zealand Landscape Classification system. In this paper we examine methods to extrapolate landscape values from this regional data set to a national level using these landscape value and character relationships. In the absence of empirical value data at a national level, we examine two quantitative approaches for extrapolating landscape values: (1) landscape component weights based on the percentage of value counts found within landscape components, and (2) landscape component weights based on the ratio of landscape values to the landscape area. We prepare and present maps of seven landscape values for the entire country of New Zealand to demonstrate the method. We conclude that landscape value extrapolation can assist impact assessment for land use change but should be kept simple for decision support.

text: The extrapolation of social landscape values to a national level in New Zealand using landscape character classification The human perception and valuation of landscapes is a complex process but has been pragmatically advanced through public participation GIS (PPGIS). PPGIS methods have the capacity to generate spatial data to empirically examine relationships between human landscape values and physical landscape character. In 2011, PPGIS methods were used to identify a range of social landscape values for two regions in southern New Zealand, Otago and Southland. Seven of these landscape values were analysed to identify significant relationships with physical landscape character from the New Zealand Landscape Classification system. In this paper we examine methods to extrapolate landscape values from this regional data set to a national level using these landscape value and character relationships. In the absence of empirical value data at a national level, we examine two quantitative approaches for extrapolating landscape values: (1) landscape component weights based on the percentage of value counts found within landscape components, and (2) landscape component weights based on the ratio of landscape values to the landscape area. We prepare and present maps of seven landscape values for the entire country of New Zealand to demonstrate the method. We conclude that landscape value extrapolation can assist impact assessment for land use change but should be kept simple for decision support.

year: 2012

title: Control of macrophytes by grass carp (ctenopharyngodon idella) in a Waikato drain, New Zealand

authors: Wells, R.D.S.

subjects: biology

abstract: Hornwort (Ceratophyllum demersum L.) and other aquatic macrophytes have historically been mechanically removed from the Rangiriri drain and Churchill East drain to maintain drain efficiency. As an alternative control method for the high plant biomass that accumulates at the end of summer, the effect of stocking diploid grass carp (Ctenopharyngodon idella L.) on the aquatic vegetation was evaluated in these Waikato drainage systems. At the start of the trial, both drains had a low diversity of aquatic macrophytes, and of the nine species (including the emergents), seven were exotic. Two months after grass carp were released to Churchill East drain (the treated drain) the four submerged and floating macrophyte species became scarce in the main drain. Over the same period, these species increased in biomass in Rangiriri drain (the untreated drain), where hornwort became dense and surface-reaching and remained so for the duration of the trial. However, grass carp did not control submerged vegetation in smaller side drains or the shallow, upper parts of the main drain, or the marginal sprawling species and emergent species. The cost of leasing the grass carp was similar to the cost of clearing the drains mechanically, but grass carp provided continuous weed control. However, subsequent to this trial, 62 dead grass carp were found in Churchill East drain in February 2001, and weed cover subsequently increased. This illustrates that grass carp management in New Zealand agricultural drains can be problematic due to periodic fish kills.

text: Control of macrophytes by grass carp (ctenopharyngodon idella) in a Waikato drain, New Zealand Hornwort (Ceratophyllum demersum L.) and other aquatic macrophytes have historically been mechanically removed from the Rangiriri drain and Churchill East drain to maintain drain efficiency. As an alternative control method for the high plant biomass that accumulates at the end of summer, the effect of stocking diploid grass carp (Ctenopharyngodon idella L.) on the aquatic vegetation was evaluated in these Waikato drainage systems. At the start of the trial, both drains had a low diversity of aquatic macrophytes, and of the nine species (including the emergents), seven were exotic. Two months after grass carp were released to Churchill East drain (the treated drain) the four submerged and floating macrophyte species became scarce in the main drain. Over the same period, these species increased in biomass in Rangiriri drain (the untreated drain), where hornwort became dense and surface-reaching and remained so for the duration of the trial. However, grass carp did not control submerged vegetation in smaller side drains or the shallow, upper parts of the main drain, or the marginal sprawling species and emergent species. The cost of leasing the grass carp was similar to the cost of clearing the drains mechanically, but grass carp provided continuous weed control. However, subsequent to this trial, 62 dead grass carp were found in Churchill East drain in February 2001, and weed cover subsequently increased. This illustrates that grass carp management in New Zealand agricultural drains can be problematic due to periodic fish kills.

year: 2003

title: Waitangi Soda Springs alum dosing – Bioavailability of aluminium 2011-2020

authors: Ling, Nicholas

abstract: Continuous alum dosing of the Waitangi Soda Springs at Lake Rotoehu commenced in 2011 to reduce inflows of dissolved reactive phosphorus to Lake Rotoehu. Analyses of bioaccumulation in the tissues of kōura and goldfish from Lake Rotoehu were undertaken on animals collected annually since 2013 to determine the bioavailability and bioaccumulation of aluminium. Lake Rotoehu kōura and goldfish collected in 2013 showed slightly elevated aluminium concentrations in the gills indicating enhanced exposure to aluminium but little evidence for significant bioaccumulation in tissues. Concentrations in goldfish liver and gills were highest in 2016, but not significantly different to goldfish collected from Lake Rotorua in 2013 and flesh concentrations were low. Analyses of animals collected in 2020 confirm these earlier findings with no evidence of enhanced bioaccumulation of aluminium in Lake Rotoehu biota.

text: Waitangi Soda Springs alum dosing – Bioavailability of aluminium 2011-2020 Continuous alum dosing of the Waitangi Soda Springs at Lake Rotoehu commenced in 2011 to reduce inflows of dissolved reactive phosphorus to Lake Rotoehu. Analyses of bioaccumulation in the tissues of kōura and goldfish from Lake Rotoehu were undertaken on animals collected annually since 2013 to determine the bioavailability and bioaccumulation of aluminium. Lake Rotoehu kōura and goldfish collected in 2013 showed slightly elevated aluminium concentrations in the gills indicating enhanced exposure to aluminium but little evidence for significant bioaccumulation in tissues. Concentrations in goldfish liver and gills were highest in 2016, but not significantly different to goldfish collected from Lake Rotorua in 2013 and flesh concentrations were low. Analyses of animals collected in 2020 confirm these earlier findings with no evidence of enhanced bioaccumulation of aluminium in Lake Rotoehu biota.

year: 2021