ORCID Profile
0000-0002-0718-0257
Current Organisations
University of Colorado at Boulder
,
University of Oregon
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Population Ecology | Ecology | Community Ecology | Invasive Species Ecology |
Ecosystem Adaptation to Climate Change | Expanding Knowledge in the Biological Sciences | Forest and Woodlands Flora, Fauna and Biodiversity
Publisher: Wiley
Date: 05-07-2022
DOI: 10.1002/EAP.2649
Abstract: Restoration ecology commonly seeks to re‐establish species of interest in degraded habitats. Despite a rich understanding of how succession influences re‐establishment, there are several outstanding questions that remain unaddressed: are short‐term abundances sufficient to determine long‐term re‐establishment success, and what factors contribute to unpredictable restorations outcomes? In other words, when restoration fails, is it because the restored habitat is substandard, because of strong competition with invasive species, or alternatively due to changing environmental conditions that would equally impact established populations? Here, we re‐purpose tools developed from modern coexistence theory to address these questions, and apply them to an effort to restore the endangered Contra Costa goldfields ( Lasthenia conjugens ) in constructed (“restored”) California vernal pools. Using 16 years of data, we construct a population model of L. conjugens , a species of conservation concern due primarily to habitat loss and invasion of exotic grasses. We show that initial, short‐term appearances of restoration success from population abundances is misleading, as year‐to‐year fluctuations cause long‐term population growth rates to fall below zero. The failure of constructed pools is driven by lower maximum growth rates compared with reference (“natural”) pools, coupled with a stronger negative sensitivity to annual fluctuations in abiotic conditions that yield decreased maximum growth rates. Nonetheless, our modeling shows that fluctuations in competition (mainly with exotic grasses) benefit L. conjugens through periods of competitive release, especially in constructed pools of intermediate pool depth. We therefore show how reductions in invasives and seed addition in pools of particular depths could change the outcome of restoration for L. conjugens . By applying a largely theoretical framework to the urgent goal of ecological restoration, our study provides a blueprint for predicting restoration success, and identifies future actions to reverse species loss.
Publisher: Wiley
Date: 25-04-2014
DOI: 10.1111/EMR.12110
Publisher: Wiley
Date: 12-2014
DOI: 10.1890/130300
Publisher: Routledge
Date: 18-05-2017
Publisher: Wiley
Date: 09-05-2014
DOI: 10.1111/DDI.12220
Publisher: Wiley
Date: 31-01-2013
Publisher: Wiley
Date: 08-07-2020
DOI: 10.1111/REC.13211
Abstract: Professor Richard Hobbs has had a profound influence on the development of the discipline of restoration ecology. With more than 300 publications spanning a broad scope of applied ecological sciences, he has collaborated with hundreds of researchers. His sometimes‐provocative insights, balanced by extensive empirical research, will have a lasting impact by encouraging people to think more broadly about the science and practice of ecological restoration. Here, on the eve of his retirement, some of his staff and students, past and present, take a retrospective look at his contributions to restoration ecology both as a scientist and as a mentor.
Publisher: Wiley
Date: 02-02-2022
DOI: 10.1111/ELE.13977
Abstract: Modelling species interactions in erse communities traditionally requires a prohibitively large number of species‐interaction coefficients, especially when considering environmental dependence of parameters. We implemented Bayesian variable selection via sparsity‐inducing priors on non‐linear species abundance models to determine which species interactions should be retained and which can be represented as an average heterospecific interaction term, reducing the number of model parameters. We evaluated model performance using simulated communities, computing out‐of‐s le predictive accuracy and parameter recovery across different input s le sizes. We applied our method to a erse empirical community, allowing us to disentangle the direct role of environmental gradients on species’ intrinsic growth rates from indirect effects via competitive interactions. We also identified a few neighbouring species from the erse community that had non‐generic interactions with our focal species. This sparse modelling approach facilitates exploration of species interactions in erse communities while maintaining a manageable number of parameters.
Publisher: Wiley
Date: 30-11-2022
Abstract: Declines in grassland ersity in response to nutrient addition are a general consequence of global change. This decline in species richness may be driven by multiple underlying processes operating at different time‐scales. Nutrient addition can reduce ersity by enhancing the rate of local extinction via competitive exclusion, or by reducing the rate of colonization by constraining the pool of species able to colonize under new conditions. Partitioning net change into extinction and colonization rates will better delineate the long‐term effect of global change in grasslands. We synthesized changes in richness in response to experimental fertilization with nitrogen, phosphorus and potassium with micronutrients across 30 grasslands. We quantified changes in local richness, colonization, and extinction over 8–10 years of nutrient addition, and compared these rates against control conditions to isolate the effect of nutrient addition from background dynamics. Total richness at steady state in the control plots was the sum of equal, relatively high rates of local colonization and extinction. On aggregate, 30%–35% of initial species were lost and the same proportion of new species were gained at least once over a decade. Absolute turnover increased with site‐level richness but was proportionately greater at lower‐richness sites relative to starting richness. Loss of total richness with nutrient addition, especially N in combination with P or K, was driven by enhanced rates of extinction with a smaller contribution from reduced colonization. Enhanced extinction and reduced colonization were disproportionately among native species, perennials, and forbs. Reduced colonization plateaued after the first few ( ) years after nutrient addition, while enhanced extinction continued throughout the first decade. Synthesis . Our results indicate a high rate of colonizations and extinctions underlying the richness of ambient communities and that nutrient enhancement drives overall declines in ersity primarily by exclusion of previously established species. Moreover, enhanced extinction continues over long time‐scales, suggesting continuous, long‐term community responses and a need for long‐term study to fully realize the extinction impact of increased nutrients on grassland composition.
Publisher: Wiley
Date: 19-01-2017
DOI: 10.1111/ECOG.02383
Publisher: Cold Spring Harbor Laboratory
Date: 26-07-2021
DOI: 10.1101/2021.07.23.453227
Abstract: 1 Modeling species interactions in erse communities traditionally requires a prohibitively large number of species-interaction coefficients, especially when considering environmental dependence of parameters. We implemented Bayesian variable selection via sparsity-inducing priors on non-linear species abundance models to determine which species-interactions should be retained and which can be represented as an average heterospecific interaction term, reducing the number of model parameters. We evaluated model performance using simulated communities, computing out-of-s le predictive accuracy and parameter recovery across different input s le sizes. We applied our method to a erse empirical community, allowing us to disentangle the direct role of environmental gradients on species’ intrinsic growth rates from indirect effects via competitive interactions. We also identified a few neighboring species from the erse community that had non-generic interactions with our focal species. This sparse modeling approach facilitates exploration of species-interactions in erse communities while maintaining a manageable number of parameters.
Publisher: Springer Science and Business Media LLC
Date: 12-04-2011
Publisher: Proceedings of the National Academy of Sciences
Date: 19-08-2019
Abstract: Accurate prediction of community responses to global change drivers (GCDs) is critical given the effects of bio ersity on ecosystem services. There is consensus that human activities are driving species extinctions at the global scale, but debate remains over whether GCDs are systematically altering local communities worldwide. Across 105 experiments that included over 400 experimental manipulations, we found evidence for a lagged response of herbaceous plant communities to GCDs caused by shifts in the identities and relative abundances of species, often without a corresponding difference in species richness. These results provide evidence that community responses are pervasive across a wide variety of GCDs on long-term temporal scales and that these responses increase in strength when multiple GCDs are simultaneously imposed.
Publisher: Cold Spring Harbor Laboratory
Date: 10-2021
Publisher: Wiley
Date: 03-2022
DOI: 10.1111/JVS.13115
Publisher: Wiley
Date: 09-07-2021
DOI: 10.1111/ELE.13838
Abstract: The effects of altered nutrient supplies and herbivore density on species ersity vary with spatial scale, because coexistence mechanisms are scale dependent. This scale dependence may alter the shape of the species–area relationship (SAR), which can be described by changes in species richness ( S ) as a power function of the s le area ( A ): S = cA z , where c and z are constants. We analysed the effects of experimental manipulations of nutrient supply and herbivore density on species richness across a range of scales (0.01–75 m 2 ) at 30 grasslands in 10 countries. We found that nutrient addition reduced the number of species that could co‐occur locally, indicated by the SAR intercepts (log c ), but did not affect the SAR slopes ( z ). As a result, proportional species loss due to nutrient enrichment was largely unchanged across s ling scales, whereas total species loss increased over threefold across our range of s ling scales.
Publisher: Wiley
Date: 31-01-2013
Start Date: 06-2021
End Date: 06-2024
Amount: $470,000.00
Funder: Australian Research Council
View Funded Activity