About
43
Publications
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Introduction
I’m broadly interested in the processes that structure communities and connecting basic theory of these processes to applied ecology. Plant community assembly has been a common theme throughout my research career, including both observational and experimental approaches, integrating evolutionary and ecological processes, exploring both above- and belowground drivers of species coexistence, and relating functional traits to species interactions and community structure.
Current institution
Additional affiliations
November 2013 - present
Position
- Ecologist
Description
- Projects focus on invasion biology, drivers of biodiversity, and community ecology with the aims of supporting management, environmental reporting, and sustainability.
November 2016 - present
Position
- Ecologist/Modeller
Description
- Several projects, including farm biodiversity assessment tools, the NZ Garden Bird Survey, state of environment reporting, and invasive species traits and impacts. I also lead a Marsden-funded research project on community ecology of bryophytes.
November 2013 - October 2016
Position
- PostDoc Position
Description
- Investigated how historical processes have contributed to current community structure and species distributions of the New Zealand flora, at both local and national scales.
Education
September 2005 - March 2011
August 1999 - May 2003
Publications
Publications (43)
Large scale changes in biodiversity and conservation management require long-term goals and planning across multiple sectors in the face of increasing global change. Major trends in land use and management interventions, species additions or losses, and climate are well recognized, but responses are still often short-term and fragmented across agen...
Specific leaf area (SLA) plays a critical role in carbon assimilation and nutrient cycling. While leaf habit (deciduous vs. evergreen) has often been recognized as a reliable predictor of SLA—with deciduous species typically having higher mean SLA values due to lower concentration of structural components compared to evergreens—high variation in SL...
Invasions by multiple non‐native plant species are common, but management programs often prioritize control of individual species that are expected to have the highest impacts. Multi‐species invasions could have larger or smaller impacts than single‐species invasions depending on how multiple co‐occurring invaders interact to alter their abundance...
Using biodiversity management within New Zealand's agricultural landscape as a case study, we apply ‘boundary science’ approaches to overcome two persistent deficiencies in environmental decision‐making: ‘evidence disparity’, the discrepancy between evidence desired and evidence generated, and ‘evidence complacency’, where evidence is not sought or...
Better biodiversity indicators are needed to address information gaps, describe trends accurately and robustly and be useful for decisionmakers. Citizen science's potential to help address these challenges often goes unrealized, despite promises by organizers to deliver such information.
This paper addresses these challenges by demonstrating the po...
Changing human behaviour to enhance agricultural sustainability outcomes is an ongoing challenge that urgently needs addressing. It requires identifying the mechanisms for the successful uptake and application of tools and behavioural interventions to mitigate the detrimental impacts of farm activities on the environment.
We combined a participator...
Mainstreaming biodiversity across government and society is recognised by international policy as critical to achieving positive conservation outcomes. With ‘participatory governance’ increasingly being applied to achieve collective action in conservation, there are growing calls to critically review such processes to capture their complexity and m...
Urban areas are hubs for invasive alien (non-native) species (IAS) which can cause major problems in and around urban areas. Urban conservation practitioners face complex decisions about which IAS require management, where and when these management interventions are necessary, and how to implement them effectively. While researchers increasingly ad...
Whole genome duplication or polyploidy is widespread among floras globally, but traditionally has been thought to have played a minor role in the evolution of island biodiversity, based on the low proportion of polyploid taxa present. We investigate five island systems (Juan Fernández, Galápagos, Canary Islands, Hawaiian Islands, and New Zealand) t...
The New Zealand flora has a high proportion of endemic species but has been invaded by almost the same number of non-native plant species. To support management of invasive plant species, we provide an updated inventory of New Zealand’s naturalised flora and compare it with the native flora to identify key taxonomic and functional distinctions. We...
Biological invasions are a major driver of ecosystem change but causes of variation in their environmental impacts over space and time remain poorly understood. Most approaches used to quantify the impacts of non‐native species assume there are interactions among per capita (i.e. individual level) effects, species abundance and the area occupied by...
In an era of anthropogenically altered disturbance regimes and increased nutrient loads, understanding how communities respond to these perturbations is essential for successful habitat restoration. Disturbance and resource supply can affect community diversity by altering community assembly processes, such as recruitment, mortality or competitive...
Evolutionary priority effects, where early‐arriving lineages occupy niche space via diversification and preclude dominance of later arrivals, have been observed in alpine and forest communities. However, the potential for evolutionary priority effects to persist in an era of rapid global change remains unclear.
Here, we use a natural experiment of...
Plant–soil feedbacks have been widely implicated as a driver of plant community diversity, and the coexistence prediction generated by a negative plant–soil feedback can be tested using the mutual invasibility criterion: if two populations are able to invade one another, this result is consistent with stable coexistence. We previously showed that t...
There are currently two medium-large, closely related, endemic New Zealand terebratulide brachiopod species assigned to the Southern Hemisphere genus Terebratella d’Orbigny, 1847. However, recently published molecular analyses reveal that the New Zealand Terebratella are only distantly related to southern South American Terebratella, which contains...
The ecological conditions promoting evolutionary priority effects, where the order and timing of ancestral species arrival into a new habitat influences extant community assembly, are poorly understood. Studies in the New Zealand alpine indicated that early‐arriving angiosperm lineages dominated communities via niche pre‐emption. Forests have a muc...
Background/Question/Methods
Little is known about the ecological conditions promoting evolutionary priority effects, when the order of ancestral species arrival into a new habitat influences extant community structure. Evidence suggests that evolutionary priority effects operate through niche pre-emption, where occupation of niche space by early-ar...
Phenotypic plasticity, the expression of traits dependent on an individual's environment, should increase the range of communities in which a plant can establish, potentially influencing community assembly. Plasticity may be induced by either the mean or variance in conditions; however, plant responses to variance in the environment remain largely...
Plant radiations are widespread but their influence on community assembly has rarely been investigated. Theory and some evidence suggest that radiations can allow lineages to monopolize niche space when founding species arrive early into new bioclimatic regions and exploit ecological opportunities. These early radiations may subsequently reduce nic...
Trait divergence between co-occurring individuals could decrease the strength of competition between these individuals, thus promoting their coexistence. To test this hypothesis, we manipulated establishment timing for four congeneric pairs of perennial plants and assessed trait plasticity. Because soil conditions can affect trait expression and co...
Background/Question/Methods
Plants experience changing environments in space and time, or environmental heterogeneity. This environmental heterogeneity may play a pivotal role in influencing invasibility, the ability of a population to grow from low density, and may assist in understanding coexistence. Early verbal theory suggested that environme...
Background/Question/Methods
The order in which species colonize a community can influence community structure, with priority effects over both ecological and evolutionary timescales often resulting in communities dominated by early colonizers. However, the strength of priority effects in plant communities varies across environmental gradients, at...
Understanding the mechanisms governing coexistence is a central goal in ecology and has implications for conserving and restoring communities, yet the high diversity in many plant communities is difficult to explain. Theory suggests that plant–soil feedbacks ( PSF ) can lead to frequency‐dependent coexistence by suppressing conspecifics more than h...
Coexistence theory has often treated environmental heterogeneity as being independent of the community composition; however biotic feedbacks such as plant-soil feedbacks (PSF) have large effects on plant performance, and create environmental heterogeneity that depends on the community composition. Understanding the importance of PSF for plant commu...
Background/Question/Methods
The outcome of competition in plants is dependent on individuals’ responses to their environment, including phenotypic trait expression. The expression of different leaf or root traits amongst individuals of the same genotype across environments could influence the outcome of competition. For example, phenotypic plasti...
Background/Question/Methods
The effects of environmental heterogeneity on plant populations are important for understanding the mechanisms governing invasibility and thus coexistence. In theory, environmental heterogeneity should interact with species’ life history to influence invasibility. Spatial heterogeneity in the soil microbiota, especiall...
Background/Question/Methods
Intraspecific variation in functional traits can affect the strength of species interactions and may ultimately affect processes of community assembly. The role of trait plasticity in mediating competition may depend on how trait expression responds to environmental conditions. Separate studies have shown that plant co...
Most studies of soil heterogeneity have focused on underlying abiotic factors such as soil nutrients. However, increasing recognition of plant–soil feedback ( PSF ) effects on plant growth, combined with the observation that PSF s operate at small spatial scales, suggests that heterogeneity due to PSF could affect plant population and community dyn...
Background/Question/Methods
Community assembly theory postulates that species will be able to coexist if they can invade one another's populations when rare--the criterion of mutual invasibility. Phenotypic plasticity in trait expression could facilitate mutual invasibility, potentially contributing to species coexistence. For example, if plastici...
The effects of exotic species invasions on biodiversity vary with spatial scale, and documentation of local-scale changes in biodiversity following invasion is generally lacking. Coupling long-term observations of local community dynamics with experiments to determine the role played by exotic species in recruitment limitation of native species wou...
Background/Question/Methods
Disturbance and resource supply can increase or decrease species diversity by altering the relative roles of community assembly mechanisms. Examining these effects is important to understand patterns of diversity, as well as how anthropogenic impacts on disturbance regimes and nutrient cycling will affect communities a...
Coexistence through a variety of mechanisms is possible for species with differential responses to environmental conditions. Understanding the role of environmental heterogeneity in mediating coexistence of species of different provenance (i.e., native vs. exotic) has important implications for theory and management. We used two California grasslan...
Biological invasions pose one of the greatest threats to global biodiversity, but many naturalized invaders coexist with the native community. Community ecology theory provides a framework for understanding the mechanisms by which invaders might coexist with native species or exclude them from the community, thus informing management practices to m...
Background/Question/Methods
Effects of biological invasions on community diversity vary with spatial scale, but temporal changes in native and exotic diversity over a range of scales are rarely documented. Understanding the cause of localized native species declines is essential to predicting effects of invaders and successfully restoring natives....
Background/Question/Methods
Heterogeneous habitats are predicted to have higher species diversity, suggesting they may be more susceptible to exotic invasions. However, native species may take advantage of habitat heterogeneity to coexist with invaders. Examining spatial and temporal variability in the composition of invaded plant communities can...
Plant-soil feedbacks can affect plant community dynamics by influencing processes of coexistence or invasion, or by maintaining alternate stable states. Darwin's naturalization hypothesis suggests that phylogenetic relatedness should be a critical factor governing such feedbacks in invaded communities but is rarely considered in soil feedback studi...
Changes in pattern of activity may help shrews survive harsh winter conditions. In particular, shrews may become less active and less nocturnal during winter. To better understand the mechanisms underlying the shrew response to winter conditions we measured several kinds of activity and an index of nocturnality (night-day ratio) for six northern sh...
