ORCID Profile
0000-0002-4164-9047
Current Organisations
NIWA - The National Institute of Water and Atmospheric Research Ltd.
,
Manaaki Whenua - Landcare Research
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Publisher: Springer Science and Business Media LLC
Date: 08-06-2016
Publisher: Informa UK Limited
Date: 10-06-2020
Publisher: Informa UK Limited
Date: 13-05-2020
Publisher: Inter-Research Science Center
Date: 20-02-2020
DOI: 10.3354/MEPS13208
Abstract: Inter-in idual differences in demographic traits of iteroparous species can arise through learning and maturation, as well as from permanent differences in in idual ‘quality’ and sex-specific constraints. As the ability to acquire energy determines the resources an in idual can allocate to reproduction and self-maintenance, foraging behavior is a key trait to study to better understand the mechanisms underlying these differences. So far, most seabird studies have focused on the effect of maturation and learning processes on foraging performance, while only a few have included measures of in idual quality. Here, we investigated the effects of age, breeding experience, sex, and in idual breeding quality on the foraging behavior and location of 83 known-age Adélie penguins at Cape Bird, Ross Sea, Antarctica. Over a 2 yr period, we showed that (1) high-quality birds ed deeper than lower quality ones, apparently catching a higher number of prey per e and targeting different foraging locations (2) females performed longer foraging trips and a higher number of es compared to males (3) there were no significant age-related differences in foraging behavior and (4) breeding experience had a weak influence on foraging behavior. We suggest that high-quality in iduals have higher physiological ability, enabling them to e deeper and forage more effectively. Further inquiry should focus on determining the physiological differences among penguins of different quality.
Publisher: American Geophysical Union (AGU)
Date: 09-2018
DOI: 10.1029/2018WR023378
Publisher: Elsevier BV
Date: 12-2015
Publisher: Wiley
Date: 14-06-2016
DOI: 10.1111/CONL.12260
Publisher: Informa UK Limited
Date: 15-10-2019
Publisher: Public Library of Science (PLoS)
Date: 30-12-2022
DOI: 10.1371/JOURNAL.PONE.0277820
Abstract: Habitat modification and introduced mammalian predators are linked to global species extinctions and declines, but their relative influences can be uncertain, often making conservation management difficult. Using landscape-scale models, we quantified the relative impacts of habitat modification and mammalian predation on the range contraction of a threatened New Zealand riverine duck. We combined 38 years of whio ( Hymenolaimus malacorhynchos ) observations with national-scale environmental data to predict relative likelihood of occurrence (RLO) under two scenarios using bootstrapped boosted regression trees (BRT). Our models used training data from contemporary environments to predict the potential contemporary whio distribution across New Zealand riverscapes in the absence of introduced mammalian predators. Then, using estimates of environments prior to human arrival, we used the same models to hindcast potential pre-human whio distribution prior to widespread land clearance. Comparing RLO differences between potential pre-human, potential contemporary and observed contemporary distributions allowed us to assess the relative impacts of the two main drivers of decline habitat modification and mammalian predation. Whio have undergone widespread catastrophic declines most likely linked to mammalian predation, with smaller declines due to habitat modification (range contractions of 95% and 37%, respectively). We also identified areas of potential contemporary habitat outside their current range that would be suitable for whio conservation if mammalian predator control could be implemented. Our approach presents a practical technique for estimating the relative importance of global change drivers in species declines and extinctions, as well as providing valuable information to improve conservation planning.
Publisher: Informa UK Limited
Date: 03-2015
DOI: 10.1071/MU14018
Publisher: Informa UK Limited
Date: 13-05-2020
Publisher: Springer Science and Business Media LLC
Date: 13-12-2019
DOI: 10.1007/S00267-019-01235-X
Abstract: A common land and water management task is to determine where and by how much source loadings need to change to meet water quality limits in receiving environments. This paper addresses the problem of quantifying changes in loading when limits are specified in many locations in a large and spatially heterogeneous catchment, accounting for cumulative downstream impacts. Current approaches to this problem tend to use either scenario analysis or optimization, which suffer from difficulties of generating scenarios that meet the limits, or high complexity of optimization approaches. In contrast, we present a novel method in which simple catchment models, load limits, upstream/downstream spatial relationships and spatial allocation rules are combined to arrive at source load changes. The process iteratively establishes the critical location (river segment or lake) where the limits are most constraining, and then adjusts sources upstream of the critical location to meet the limit at that location. The method is demonstrated with application to New Zealand (268,000 km
Publisher: Elsevier BV
Date: 2014
Publisher: Proceedings of the National Academy of Sciences
Date: 10-12-2018
Abstract: Island biogeography theory posits that species richness increases with island size and decreases with isolation. This logic underpins much conservation policy and regulation, with preference given to conserving large, highly connected areas, and relative ambivalence shown toward protecting small, isolated habitat patches. We undertook a global synthesis of the relationship between the conservation value of habitat patches and their size and isolation, based on 31 systematic conservation planning studies across four continents. We found that small, isolated patches are inordinately important for bio ersity conservation. Our results provide a powerful argument for redressing the neglect of small, isolated habitat patches, for urgently prioritizing their restoration, and for avoiding simplistic application of island biogeography theory in conservation decisions.
Publisher: Unpublished
Date: 2017
Publisher: Elsevier BV
Date: 11-2008
Publisher: Regional Euro-Asian Biological Invasions Centre Oy (REABIC)
Date: 2021
Publisher: Springer Science and Business Media LLC
Date: 18-01-2015
Publisher: Springer Science and Business Media LLC
Date: 13-10-2013
Publisher: CSIRO Publishing
Date: 30-09-2021
DOI: 10.1071/MF21086
Abstract: Trends at 1051 river monitoring sites across New Zealand incrementing annually for time windows of 10 and 20 years over the 28-year period ending 2017 were assessed from regular observations of six water quality variables. Between-site variation in trend strength and direction was modelled as a function of an indicator based on the Southern Oscillation Index (SOI) and the mean of and changes to catchment: (1) stocking intensity associated with pastoral livestock and (2) area associated with plantation forest. The SOI indicator made consistent contributions to the models for the 10-year windows, but the land use indicators did not, indicating that land use signals were generally sw ed by the effects of climate variability at this timescale. Some land use indicators made consistent and certain contributions to the models for the 20-year time windows. Depending on the water quality variable, some land use indicators were associated with both water quality improvement and degradation. The relationships were generally consistent with plausible explanations including changes in land use, land use intensity and land management practices. Robust attribution of water quality changes to changes to specific agricultural land uses will enable the development of precise and effective policies to achieve water quality improvement.
Publisher: Wiley
Date: 03-10-2021
DOI: 10.1002/RRA.3870
Abstract: River water temperature is known to be important for water quality and ecosystem processes. We quantified the degree to which lower river flows are associated with warmer river water, after accounting for seasonality and meteorological variability. We applied a systematic methodology to analyse observed mean daily river water temperature and mean daily river flow from 47 sites draining mountain, hill, and lowland catchments across the Canterbury region of Aotearoa New Zealand. We fitted regression models to remove seasonal patterns from all variables, then removed correlations between water temperature and each of three meteorological variables (solar radiation, air temperature, and earth temperature) before quantifying water temperature‐river flow relationships. Strong seasonal patterns were present in water temperature and each meteorological variable across all sites. Many sites also showed strong seasonal patterns in river flows. We demonstrated that seasonal patterns must be accounted for before day‐to‐day associations between water temperature and meteorological variables or river flow can be characterised. Higher water temperatures were associated with lower flows for 46 of 47 sites, even after having accounted for seasonality and associations with each meteorological variable. Increases in water temperature associated with a hypothetical reduction in river flow from the median to the fifth percentile varied with the site but were 0.5°C on average. This finding has important implications for river flow management because it indicates that increased river water temperatures would accompany reduced river flows regardless of site or catchment characteristics.
Publisher: Wiley
Date: 11-03-2014
DOI: 10.1111/COBI.12257
Abstract: The consideration of information on social values in conjunction with biological data is critical for achieving both socially acceptable and scientifically defensible conservation planning outcomes. However, the influence of social values on spatial conservation priorities has received limited attention and is poorly understood. We present an approach that incorporates quantitative data on social values for conservation and social preferences for development into spatial conservation planning. We undertook a public participation GIS survey to spatially represent social values and development preferences and used species distribution models for 7 threatened fauna species to represent biological values. These spatially explicit data were simultaneously included in the conservation planning software Zonation to examine how conservation priorities changed with the inclusion of social data. Integrating spatially explicit information about social values and development preferences with biological data produced prioritizations that differed spatially from the solution based on only biological data. However, the integrated solutions protected a similar proportion of the species' distributions, indicating that Zonation effectively combined the biological and social data to produce socially feasible conservation solutions of approximately equivalent biological value. We were able to identify areas of the landscape where synergies and conflicts between different value sets are likely to occur. Identification of these synergies and conflicts will allow decision makers to target communication strategies to specific areas and ensure effective community engagement and positive conservation outcomes.
Publisher: Wiley
Date: 03-07-2020
DOI: 10.1111/COBI.13524
Publisher: Wiley
Date: 28-10-2010
Publisher: Springer Science and Business Media LLC
Date: 08-2020
DOI: 10.1007/S10745-020-00170-4
Abstract: The global emphasis on stakeholder engagement in protected area management has increased over the last three decades. Here we present key values of statutory and non-statutory stakeholder groups as they relate to their relationship with the former Te Urewera National Park (NP), New Zealand, which is now recognised as “a legal entity” with “all the rights , powers, duties, and liabilities of a legal person.” Non-statutory stakeholders conveyed a close, personal connection to Te Urewera NP in terms of heritage and legacy, which include both consumptive (e.g., hunting fishing) and non-consumptive use (e.g., sight-seeing, hiking, boating). In contrast, statutory stakeholders expressed a more distant and procedural relationship with the park. Both stakeholder groups perceived the possible transfer of ownership or governance of Te Urewera NP to Tūhoe (the Indigenous Māori peoples of the Te Urewera region) favourably and expressed a desire to be engaged in the future stewardship of the NP. Stakeholders considered the fostering of relations with Tūhoe and other stakeholder groups as important to nurturing and maintaining their links with the area in future. Importantly, common interests that emerge from these relationships can increase mutual understanding between cultures and willingness to collaborate. Moreover, we posit that the legal personhood status for protected areas will be a powerful tool for reconciling pluralistic values and enable deliberative processes and flexible modes of collaboration between Indigenous peoples and non-indigenous stakeholders.
Publisher: Elsevier BV
Date: 12-2022
Publisher: Unpublished
Date: 2017
Publisher: Inter-Research Science Center
Date: 16-03-2015
DOI: 10.3354/MEPS11130
Publisher: Inter-Research Science Center
Date: 09-07-2020
DOI: 10.3354/MEPS13370
Abstract: Intraspecific competition for food can be especially high in colonial breeding seabirds. To minimize colony-induced or annual foraging challenges, diet may vary among in iduals, but few studies have simultaneously investigated the effects of both extrinsic conditions (e.g. colony or year effects) and parameters of an in idual (e.g. sex, age or in idual quality) on diet in seabirds. Using stable isotope analyses, we studied the diet of 214 Adélie penguins Pygoscelis adeliae of known sex, age and breeding quality, nesting in 2 colonies on Ross Island, Antarctica, over 3 breeding seasons. During the study, δ 15 N and δ 13 C isotope values were lower in penguins breeding at Cape Crozier compared to those at Cape Bird, revealing a difference in prey proportions. Cape Bird penguins were estimated to consistently consume more energy-rich silverfish Pleuragramma antarctica , while birds at Cape Crozier ate more crystal krill Euphausia crystallorophias . We also found inter-annual differences in diet, with a higher dietary fish proportion in both colonies during 2011. Males had significantly higher δ 15 N values, indicating a higher fish consumption than females. This sexual segregation in diet was particularly pronounced at Cape Bird, where the overall isotopic niche was wider than at Cape Crozier. Differences in diet among adults of varying ages only existed at Cape Bird, where middle-aged penguins consumed more fish than old and young penguins. This study provides evidence that Adélie penguin diet is largely driven by annual, seasonal and local abundances of prey, with only some in iduals selectively foraging for more nutritional prey if prey choices are present.
Publisher: Unpublished
Date: 2017
Location: New Zealand
Location: New Zealand
Start Date: 2018
End Date: 2022
Funder: Ministry of Business, Innovation and Employment
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