George L. W. Perry's research while affiliated with University of Auckland and other places

Publications (197)

Article
Conservation decision makers must negotiate social and technical complexities to achieve desired biodiversity outcomes. Quantitative models can inform decision making, by evaluating and predicting management outcomes, so that comparisons can be made between alternative courses of action. However, whether a proposed action is appropriate for impleme...
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Long time series of temperature and rainfall grids are fundamental to understanding how these environmental variables affect environmental or ecological patterns and processes such as plant distributions, plant and animal phenology, wildfires, and hydrology. Ideally such temperature and rainfall grids are openly available and associated with uncert...
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Despite many sectors of society striving for sustainability in environmental management, humans often fail to identify and act on the connections and processes responsible for social–ecological tipping points. Part of the problem is the fracturing of environmental management and social–ecological research into ecosystem domains (land, freshwater, a...
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Eco-evolutionary priority effects, in which early arriving taxa pre-empt environmental niches and evolve to exclude or marginalise later arriving taxa, have been claimed to have influenced current vegetation communities in New Zealand. We here critically assess this claim. An examination of the entire New Zealand conifer and angiosperm flora shows...
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Careful development of place-based catenal models and their application as transferable archetypes provides an integrative and generalisable framework for scientifically-informed approaches to environmental management. A workshop and field excursion to the Source Zone of the Yellow River in western China in July 2019 brought together local experts...
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Sleeper populations of non-native species can remain at low abundance for decades before irrupting. For over a century, fallow deer (Dama dama) in the island state of Tasmania, Australia, remained at low abundance and close to the region in which they were released. Recently, there are indications the population has increased in abundance and distr...
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River networks are frequently simulated for use in the development and testing of ecological theory. Currently, two main algorithms are used, stochastic branching networks (SBNs) and optimal channel networks (OCNs). The topology of these simulated networks and “real” rivers is often quantified using graph theoretic metrics; however, to date there h...
Preprint
Long time-series of weather grids are fundamental to understanding how weather affects environmental or ecological patterns and processes such as plant distributions, plant and animal phenology, wildfires, and hydrology. Ideally such weather grids should be openly available and be associated with uncertainties so that users can understand any data...
Chapter
Predictions of sediment flux and the evolutionary trajectory of river systems cannot be conducted effectively independent from quantitative understandings of sediment (dis)connectivity. This requires analysis of structural and functional interactions within and between landscape compartments, and the way these interactions play out at the catchment...
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1. Many ecological functions, including seed dispersal, pollination and the flow of nutrients between ecosystems, result from the movement of animals. The ongoing reduction and extinction of animal populations and species means that these functions are reduced or lost. As a result, conservation and restoration activities often seek to reinstate eco...
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Human activity is changing the biosphere in unprecedented ways, and addressing this challenge will require changes in individual and community patterns of behavior. One approach to managing individual behaviors is “top-down” and involves imposing sanctions through legislative frameworks. However, of itself, a top-down framework does not appear suff...
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1. Biological invasions are a major threat to biodiversity and human well-being. Scientists and environmental managers typically seek ecological solutions to the biological invasion problem. However, micro-scale social factors, such as landowner attitudes and social interactions that underlie landowners' willingness to control invasive species, may...
Preprint
Full-text available
Sleeper populations of non-native species can remain at low abundance for decades before irrupting. For over a century, fallow deer ( Dama dama ) in the island state of Tasmania, Australia, remained at low abundance and close to the region in which they were released. Recently, there are indications the population has increased in abundance and dis...
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Understanding the function of social networks can make a critical contribution to achieving desirable environmental outcomes. Social-ecological systems are complex, adaptive systems in which environmental decision makers adapt to a changing social and ecological context. However, it remains unclear how multiple social influences interact with envir...
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The Proceedings of the Ecological Society of New Zealand (PESNZ) and its continuation, the New Zealand Journal of Ecology (NZJE), published more than 1250 articles over the 58 years from 1961–2019. Over this period, the emphasis of ecology as a science and the social context in which it is embedded have changed. Here we provide a bibliometric analy...
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Fossilized gut contents suggest that seeds consumed by dinosaurs may have remained intact in their stomachs, and since seed dispersal distance increases with body-mass in extant vertebrates, dinosaurs may have moved seeds long distances. I simulated seed dispersal by dinosaurs across body-masses from 1 × 10 ¹ to 8 × 10 ⁴ kg using allometric random...
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As ecological patterns are scale dependent, making decisions about sampling design critical. In the context of community assembly, many metrics have been developed to quantify species segregation and aggregation, of which the checkerboard metric (C-score) and the V-ratio are widely used. Using data that describe the spatial pattern of four species-...
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Morphology and phenology influence plant–pollinator network structure, but whether they generate more stable pairwise interactions with higher pollination success remains unknown. Here we evaluate the importance of morphological trait matching, phenological overlap and specialisation for the spatio‐temporal stability (measured as variability) of pl...
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Niche and neutral processes jointly influence species interactions. Predictions of interactions based on these processes assume that they operate similarly across all species. However, species characteristics could systematically create differences in the strength of niche or neutral processes for each interspecific interaction. We used national‐le...
Article
Sustaining ecosystem services (ES) is a key interest in the management of land use in multifunctional landscapes (i.e. ES that support ecosystem function and sustain human livelihoods). In making land management decisions, it is important to understand the relationships and spatial distributions of multiple ES, and the synergies and trade-offs betw...
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Codling moth, Cydia pomonella (Lepidoptera: Tortricidae), is a phytosanitary pest of New Zealand's export apples. The sterile insect technique supplements other controls in an eradication attempt at an isolated group of orchards in Hawke's Bay, New Zealand. There has been no attempt in New Zealand to characterize potential sources of uncontrolled p...
Article
Aim Island isolation is measured in many ways. We seek to determine what the underlying latent factors characterizing these measures are, in order to understand how they mechanistically drive island biogeographical patterns and in order to recommend the most parsimonious measures. We then test the discriminatory power of the identified components a...
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Flightless birds were once the largest and heaviest terrestrial fauna on many archipelagos around the world. Robust approaches for estimating their population parameters are essential for understanding prehistoric insular ecosystems and extinction processes. Body mass and population density are negatively related for extant flightless bird species,...
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New, more socially-acceptable technologies are being developed to suppress horticultural pests, because suppression is technically difficult with current technologies, especially in urban areas. One technique involves the release of sterile insects to prevent offspring in the next generation. This technology involves aerial or ground release system...
Article
1.Forests in which conifers and angiosperms co‐exist in the canopy with a well‐developed understorey/subcanopy have often been conceptualised as three component systems. In these systems, the co‐existence and regeneration of the two canopy tree components may be mediated by a third component in the understory and/or subcanopy, e.g. palms, bamboo, o...
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Large animals provide crucial seed dispersal services, yet face continued threats and are susceptible to changes in landscape composition and configuration. Thus, there is a growing imperative to improve understanding of animal‐generated seed dispersal using models that incorporate spatial complexity in a realistic, yet tractable, way. We developed...
Article
• Some extinctions have obvious drivers (e.g. over‐harvesting), while others can be less obvious and arise from multiple interacting factors. The extinction of the New Zealand grayling (Prototroctes oxyrhynchus ) has been blamed on over‐fishing and predation by introduced trout, but these explanations fail to account for the species disappearance f...
Article
Disruption of seed dispersal processes may affect plant population spatial structure. We used a spatial simulation model and an empirical case study to assess the conditions under which the loss of seed dispersers has a detectable effect on a species' spatial pattern. Our simulation experiments suggested that detecting spatial change following disp...
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Global environmental change and humanity's growing demands for resources have generated concerns regarding how much pressure Earth systems can absorb without drastic, potentially irreversible consequences. In natural resource production systems, tipping points can generate immediate threats to human well-being. However, empirically exploiting conce...
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Metapopulation persistence depends on connectivity between habitat patches. While emphasis has been placed on the spatial dynamics of connectivity, much less has been placed on its short‐term temporal dynamics. In many terrestrial and aquatic ecosystems, however, transient (short‐term) changes in connectivity occur as habitat patches are connected...
Preprint
Global environmental change and humanity's growing demands for resources have generated concerns regarding how much pressure Earth systems can absorb without drastic, potentially irreversible consequences. In natural resource production systems, tipping points can generate immediate threats to human well-being. However, empirically exploiting conce...
Data
Overview, Design Concepts, Details and Preliminary testing and parameterisation of the dispersal model
Data
Model verification via independent analysis of each biological trait and its interactions with landscape structure
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Dispersal is fundamental to population dynamics and hence extinction risk. The dispersal success of animals depends on the biophysical structure of their environments and their biological traits; however, comparatively little is known about how evolutionary trade-offs among suites of biological traits affect dispersal potential. We developed a spat...
Article
Forest community assembly is usually framed in terms of sporophyte dynamics; however, the recruitment and maintenance of fern populations, frequently influential in forest composition and structure, are initially determined by gametophytes. Sporophytes of three Cyathea tree fern species show habitat partitioning along gradients of phosphorus and li...
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Increasing evidence indicates that forest disturbances are changing in response to global change, yet local variability in disturbance remains high. We quantified this considerable variability and analyzed whether recent disturbance episodes around the globe were consistently driven by climate, and if human influence modulates patterns of forest di...
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Advances in data acquisition and statistical methodology have led to growing use of machine-learning methods to predict geomorphic disturbance events. However, capturing the data required to parameterize these models is challenging because of expense or, more fundamentally, because the phenomenon of interest occurs infrequently. Thus, it is importa...
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There is a growing use of bottom-up simulation models to reconstruct past human-environment interactions. Such detailed representations pose difficult questions not only in their design (the generality-realism trade-off) but also about the inferences that are made from them. The historical sciences are faced with seeking to make robust inferences f...
Article
Large areas of alpine meadow across the Qinghai-Tibet Plateau (QTP), western China, are undergoing degradation. Drawing upon field and remotely sensed data we develop a spatially explicit grid-based simulation model to explore the long-term dynamics of alpine meadow communities in this area. Our model represents the spatial dynamics of four plant f...
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Invasive species can cause shifts in vegetation composition and fire regimes by initiating positive vegetation-fire feedbacks. To understand the mechanisms underpinning these shifts, we need to determine how invasive species interact with other species when burned in combination and thus how they may influence net flammability in the communities th...
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Biodiversity assets often require conservation management, which, in turn, necessitates decisions about which ecosystem, community or species should be prioritised to receive resources. Population viability analysis (PVA) uses a suite of quantitative methods to estimate the likelihood of population decline and extinction for a given species, and ca...
Article
Questions Large pteridophytes frequently co‐occur with conifers and angiosperms in the understorey of temperate broadleaved‐podocarp forests but interactions between them are poorly understood. We evaluated the impact of tree ferns on the regeneration niche of vascular woody species to determine whether tree ferns function as niche modifiers and in...
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Abstract 1. In the context of ongoing climatic warming, forest landscapes face increasing risk of conversion to non-forest vegetation through alteration of their fire regimes and their post-fire recovery dynamics. However, this pressure could be amplified or dampened, depending on how fire-driven changes to vegetation feed back to alter the extent...
Article
The dietary breadth of invaders can influence their success, and having a wide dietary niche can facilitate the spread and survival of invaders under a variety of resource scenarios. The western mosquitofish (Gambusia affinis) is a globally distributed freshwater invasive fish. The spread of G. affinis is associated with agricultural land use, alth...
Article
The rent gap is the difference between the actual and potential ground rent of a site. This paper estimates the rent gap into two ways: gaps estimated using actual and potential ground rents at the same scale, and those based on different scales, and unpacks the relationship between renovation and both of these rent gaps via logistic regression. Us...
Article
Landscape connectivity estimates are widely used to inform species conservation management. However, although many landscapes and species behaviours change over time, such as between seasons, the vast majority of studies view connectivity as static. Calls have therefore been made to use multiple connectivity estimates to adequately capture periodic...
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The New Zealand conifers (20 species of trees and shrubs in the Araucariaceae, Podocarpaceae, and Cupressaceae) are often regarded as ancient Gondwanan elements, but mostly originated much later. Often thought of as tall trees of humid, warm forests, they are present throughout in alpine shrublands, tree lines, bogs, swamps, and in dry, frost-prone...
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Background Ecologists fiercely debate the role of soil conditions and fire regimes in controlling forest – savanna boundaries. A prominent component of this debate centres on the plausibility and existence of fire-mediated alternative stable state dynamics (FMASS), a model first proposed by the Tasmanian ecologist WD Jackson in 1968. The FMASS mode...
Article
Due to increasing habitat fragmentation and concern about its ecological effects, there has been an upsurge in the use of landscape connectivity estimates in conservation planning. Measuring connectivity is challenging, resulting in a limited understanding of the efficacy of connectivity estimation techniques and the conditions under which they per...
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Cyathea medullaris (Cyatheaceae) is a frequent pioneer of disturbed areas (e.g. landslides) or edge environments, sometimes forming near continuous canopies. We test the hypothesis that colonisation by this species as a pioneer alters the seedling assemblage to favour more shade-tolerant broadleaved trees than that beneath another common native pio...
Article
Fire regimes are powerful selective filters. In New Zealand, fire activity was rare before human settlement, and New Zealand’s indigenous woody flora shows little adaptation to frequent fire. One of the few woody indigenous species to show adaptation to frequent fire is Leptospermum scoparium (Myrtaceae), a Plio-Pleistocene immigrant from Australia...
Article
Individual-based models (IBMs) are increasingly used to explore ecological systems and, in particular, the emergent outcomes of individual-level processes. A major challenge in developing IBMs to investigate the movement ecology of animals is that such models must represent and parameterise unobserved behaviours occurring at multiple hierarchical l...
Article
Understanding the interactive effects of fragmentation and invasive species on forest dynamics requires a long-term perspective because they are difficult to assess in the medium- to long-term using observational or experimental data alone. In such settings ecological models have an important role to play. Here we describe the implementation of a s...
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Deterministic and stochastic factors interact to generate biogeographic patterns in fungal communities, challenging efforts to predict which fungal assemblages will develop in association with introduced plants. The coastal dune grass Ammophila arenaria has been moved around the world. We sampled A. arenaria roots in its native range in the United...
Article
Immigrant floras often have distinctive traits, well suited to the host region but absent from the autochthonous flora. An example is serotiny in the New Zealand (NZ) small tree, Leptospermum scoparium (Myrtaceae) belonging to a strongly fire-adapted Australian clade. Serotiny in L. scoparium has been attributed either to strong selection by fire s...
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Land-use change and invasive species pose major threats to ecosystems globally. These stressors can act together, with disturbance due to changes in land-use facilitating invasion. We examined the potential for agricultural land use to facilitate the establishment and population growth (abundance) of a globally invasive fish (Gambusia affinis). To...
Article
Plant regeneration strategies are commonly dichotomised as ‘resprouter’ v. ‘non-resprouter’, but this fails to recognise that the extent and type of resprouting following fire disturbance vary within species. Here, we report a case of widespread mortality of resprouters following a fire that burnt 98% of an 80-km² island in Bass Strait, Australia....
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Altered fire regimes in the face of climatic and land-use change could potentially transform large areas from forest to shorter-statured or open-canopy vegetation. There is growing concern that once initiated, these nonforested landscapes could be perpetuated almost indefinitely through a suite of positive feedbacks with fire. The rapid deforestati...
Article
Estimates of landscape connectivity are routinely used to inform decision-making by conservation biologists. Most estimates of connectivity rely on cost-surfaces: raster representations of landscapes in which cost values represent the difficulty involved with traversing an area. However, there is considerable uncertainty in the generation of cost-s...
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We propose the use of archetypes as a way of moving between conceptual framings, empirical observations and the dichotomous classification rules upon which maps are based. An archetype is a conceptualisation of an entire category or class of objects. Archetypes can be framed as abstract exemplars of classes, conceptual models linking form and proce...