Journal Articles
Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915
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Item Micro Gondwana: soil and litter mesofauna in the subalpine and alpine of North-West Nelson, southern New Zealand(Taylor and Francis Group on behalf of the Royal Society of New Zealand, 2025-05-21) Minor MA; Robertson AW; Ashwood FAlpine ecosystems are vulnerable to the warming climate, yet alpine soil mesofauna remains the less studied part of NZ biodiversity. Here we present a survey of soil mesofauna communities of three mountain peaks in the Nelson-Tasman and Marlborough regions of the South Island of New Zealand. We assessed changes in abundance, diversity and trophic composition along the elevational gradient from subalpine forests to alpine herb fields (800–1600 m a.s.l.) and analysed the influence of selected environmental factors on mesofauna. Taxon richness was expected to decrease and the proportion of predators to increase in alpine habitats, as has been observed elsewhere. Sub-alpine beech forests harboured a high diversity of soil mesofauna, many of which are Gondwanan relics. There was a decline in abundance and taxonomic richness of mesofauna with increasing elevation. However, no proportional increase in predators with increasing elevation was seen–alpine mesofauna assemblages had lower predator-to-herbivore ratios than upland forests. Several interesting taxa–harpacticoid copepods, moss bugs (Hemiptera: Peloridiidae), unique-headed bugs (Hemiptera: Enicocephalomorpha), micro-spiders, mite harvestmen, Neelidae springtails and acarifauna are discussed in more detail. Baseline data such as these advance the knowledge of native fauna and provide a baseline for ecological monitoring in the alpine zone.Item Density matters: How population dynamics of house mice (Mus musculus) inform the epidemiology of Leptospira(John Wiley & Sons Ltd on behalf of British Ecological Society, 2024-07-22) Moinet M; Abrahão CR; Gasparotto VPO; Wilkinson DA; Vallée E; Benschop J; Russell JC; Elderd B1. Rodents are maintenance hosts of numerous pathogens, and both their density and the pathogen prevalence determine the risk they pose to other animals or humans. However, density is often overlooked. We investigated a capture-mark-recapture-sampling strategy to study introduced mice (Mus musculus) and Leptospira as a model and demonstrate the advantages of a combined approach. 2. We estimated population density and Leptospira prevalence in mice in a replicated longitudinal survey conducted between 2016 and 2018. Capture-mark-recapture sessions were undertaken at two sites in Spring and Autumn and blood and kidney samples were collected at the end of each session. Mouse density and areas of activity were estimated using spatially explicit capture–recapture (SECR) models and both were compared between Leptospira positive and negative mice. Leptospira exposure and shedding status were estimated using Microscopic Agglutination Test, and a combination of culture and lipL32 PCR on kidneys. 3. Leptospira prevalence was higher in spring (83%–86%) than in autumn (31%–37%) and mouse densities simultaneously varied from 3.6 to 55.9/ha. However, despite these variations in prevalence and density, the density of infected animals remained relatively constant over time (3–8/ha). Shedding or being seropositive was also associated with the activity of mice. Shedding or seropositive mice had a larger activity area, and seropositive mice were trapped on average 1 day earlier than seronegative mice. 4. Synthesis and applications: Our results show how understanding the population dynamics of pathogen-carrying rodents is critical in epidemiology. The wider movement patterns and easier encounters of positive mice highlight the possibility of biases in classical prevalence surveys and have implications for disease transmission within and between species. Importantly, and quite counter-intuitively, Leptospira prevalence was negatively associated with mouse density, resulting in a constant density of shedders that contradicts the conventional view of higher exposure risk at high rodent density. More broadly, such sampling designs can improve animal and disease control policies and better inform modelling studies by providing more parameter estimates than classical prevalence surveys.Item Earthquake impacts on a protected pinniped in New Zealand(John Wiley and Sons, Inc., 2024-01-03) Hall AA; Chilvers BL; Weir JS; Boren LJThe impacts of natural disasters on marine mammals are poorly understood and difficult to study, which can hamper management responses following such events. This study provides the first distribution and abundance assessment of New Zealand fur seal (NZFS: Arctocephalus forsteri) colonies around Kaikōura, New Zealand, since a 7.8 magnitude earthquake in November 2016 caused substantial changes to both the local marine and terrestrial environments, and led to the reconstruction of a major highway that runs adjacent to NZFS colonies. Mark–recapture and direct counts in the 2022–2023 breeding season estimated pup production for NZFS breeding colonies along the Kaikōura coast. Using established multipliers, pup estimates were used to provide the first comprehensive population estimate for Kaikōura's NZFS population since the earthquake. Three new colonies and three new subcolonies were assessed and recorded, additional to reassessments of two established colonies. Overall, Kaikōura's NZFS population has grown and spread post-earthquake, with an upper total population estimate of between 21,560 and 28,327 animals in the 2022–2023 breeding season. Some sites, such as Lynch's Reef, appear to have benefited from earthquake-induced coastal uplift, with pup production increasing. Contrastingly, the estimated 2,401 (±99) pups produced at Ōhau Point in 2023 is similar to pre-earthquake estimates. This indicates that the earthquake has disrupted previously documented growth at this site. The distribution of NZFS breeding at Ōhau Point has also changed substantially since the last pre-earthquake assessment. From these findings, alterations to the Ōhau Point New Zealand Fur Seal Sanctuary and similar protections at other locations on the Kaikōura coast are suggested, as greater numbers of NZFSs are now accessible to human interaction and disturbance. The results demonstrate both how natural disasters and subsequent infrastructure modifications can impact coastal species and how conservation measures may need to be amended accordingly.Item Non-linear models of species' responses to environmental and spatial gradients(John Wiley and Sons Ltd, 2022-12) Anderson MJ; Walsh DCI; Sweatman WL; Punnett AJSpecies' responses to broad-scale environmental or spatial gradients are typically unimodal. Current models of species' responses along gradients tend to be overly simplistic (e.g., linear, quadratic or Gaussian GLMs), or are suitably flexible (e.g., splines, GAMs) but lack direct ecologically interpretable parameters. We describe a parametric framework for species-environment non-linear modelling (‘senlm’). The framework has two components: (i) a non-linear parametric mathematical function to model the mean species response along a gradient that allows asymmetry, flattening/peakedness or bimodality; and (ii) a statistical error distribution tailored for ecological data types, allowing intrinsic mean–variance relationships and zero-inflation. We demonstrate the utility of this model framework, highlighting the flexibility of a range of possible mean functions and a broad range of potential error distributions, in analyses of fish species' abundances along a depth gradient, and how they change over time and at different latitudes.