ORCID Profile
0000-0001-7827-1028
Current Organisation
University of Adelaide
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Publisher: Wiley
Date: 04-08-2019
DOI: 10.1111/AVSC.12448
Abstract: Niche complementarity is often invoked to explain co‐existence between native and alien plant species in grasslands. However, positive correlations between native and alien plant ersity observed in recent studies could mask the displacement of particular native species and functional groups or the negative effects of particular alien species. We asked: do alien species alter the species composition or proportions of growth forms in grasslands? Do particular alien species decrease native plant ersity? South Australian grasslands. We performed RDA ordination on growth form abundances or Hellinger‐transformed species abundances obtained from plot‐based surveys, constrained by alien species richness and cumulative cover. Control variables (climate, soil, land use and geographic space) were partialled out. We related in idual alien species abundances to native richness, ersity and cover. We tested for functional differences between coexisting growth forms using trait hypervolumes. While alien richness and cover explained just 2% of variance in native species composition (control variables 17%), aliens explained 18% of variance in native growth form abundance (control variables 33%), and were associated with increased herb and grass cover. Few in idual alien species were associated with strong negative or positive differences in native richness, ersity or cover: correlations followed a Gaussian distribution with near‐zero mean. Trait hypervolumes differed between native and alien herbs with an overlap of 0.44, indicating substantial, but not complete, functional differences. Given environmental context, alien cover was a good predictor of native herb and grass abundance relative to woody growth forms, but not of species composition per se. While the direction of causality is equivocal, aliens may facilitate native grasses and herbs, and niche complementarity may be involved. Due to functional redundancy across the species pool, the resulting species composition appears to be spatially contingent. Importantly for management, we identify alien species associated with reduced native ersity.
Publisher: Inter-Research Science Center
Date: 20-02-2020
DOI: 10.3354/MEPS13221
Abstract: Quantifying the trophic structure and interactions of deepwater ( m depth) elasmobranch assemblages is required to improve our understanding of deepwater ecosystems and the impacts of increased deepwater exploitation. To this end, we investigated the trophic ecology of deepwater elasmobranchs on the Great Barrier Reef (GBR) using a stable isotope (δ 13 C and δ 15 N) approach. Our study included 4 species captured in the southern GBR deepwater eastern king prawn trawl fishery: the eastern spotted gummy shark Mustelus walkeri , the piked spurdog Squalus megalops , the pale spotted catshark Asymbolus pallidus , and the Argus skate Dentiraja polyommata. The δ 13 C and δ 15 N values of all 4 species ranged from -18.6 to -16.2‰ and 8.3 to 13.8‰, respectively. The small δ 13 C range was likely due to the limited number of unique carbon baseline sources typically found in deepwater environments. Despite this, 3 of the 4 species exhibited relatively low core (40% SEA b ) isotopic niche overlap ( to 44%). Isotopic niche separation may be driven by multiple interacting factors including morphology, feeding strategies, or resource partitioning to reduce competition. Isotope analysis also provided evidence for intraspecific variation S. megalops, D. polyommata and M. walkeri exhibited significant increases in δ 15 N (~3‰) and δ 13 C (~2‰) with size. Latitude, longitude, and depth had statistically significant but comparatively minor effects on isotope values (≤1‰) of the 4 species. Cumulatively, our results indicate that isotopic variation among deepwater elasmobranchs on the GBR is principally driven by size and species-level differences in resource use.
Publisher: California Digital Library (CDL)
Date: 15-12-2020
Publisher: Springer Science and Business Media LLC
Date: 30-09-2021
DOI: 10.1038/S41597-021-01006-6
Abstract: We introduce the AusTraits database - a compilation of values of plant traits for taxa in the Australian flora (hereafter AusTraits). AusTraits synthesises data on 448 traits across 28,640 taxa from field c aigns, published literature, taxonomic monographs, and in idual taxon descriptions. Traits vary in scope from physiological measures of performance (e.g. photosynthetic gas exchange, water-use efficiency) to morphological attributes (e.g. leaf area, seed mass, plant height) which link to aspects of ecological variation. AusTraits contains curated and harmonised in idual- and species-level measurements coupled to, where available, contextual information on site properties and experimental conditions. This article provides information on version 3.0.2 of AusTraits which contains data for 997,808 trait-by-taxon combinations. We envision AusTraits as an ongoing collaborative initiative for easily archiving and sharing trait data, which also provides a template for other national or regional initiatives globally to fill persistent gaps in trait knowledge.
Publisher: Springer Science and Business Media LLC
Date: 19-02-2016
Publisher: Wiley
Date: 07-2018
DOI: 10.1002/LOM3.10258
Publisher: Elsevier BV
Date: 09-2015
Publisher: Public Library of Science (PLoS)
Date: 14-12-2022
DOI: 10.1371/JOURNAL.PONE.0278833
Abstract: Monitoring shifts in vegetation composition over time is essential for tracking bio ersity changes and for designing ecosystem management strategies. In Australia, the Terrestrial Ecosystem Research Network (TERN) provides a continent-wide network of monitoring sites (AusPlots) that can be used to assess the shifts in vegetation composition and structure of Australian Major Vegetation Groups (MVGs). Here we use time-series site data to quantify the extent and rate of MVG shifts between repeat visits and to recommend the most appropriate s ling frequency for specific MVGs. The research area spans a ~1,500 km latitudinal gradient within south/central Australia from arid rangelands in the north to Mediterranean vegetation in the south. The standardized AusPlots protocol was employed to repeatedly survey 103 one-hectare plots, assessed between 2011 and 2019. Floristic and growth form dissimilarities between visits were calculated with distance metrics and then regressed against survey interval. Multivariate ordination was used to explore temporal floristic shifts. Rank-dominance curves were used to display variations in species’ importance. Between repeated visits, sites exhibited high variability for all vegetation parameters and trajectories. However, several trends emerged: (a) Species composition moved away from baseline linearly with intervals between surveys. (b) The rate of species turnover was approximately double in communities that are herbaceous versus woody-dominated. (c) Species abundances and growth forms shift at different speeds. All floristic and structural metrics shifted between re-visits, with varying magnitude and speed, but herbaceous-dominated plots showed higher floristic dynamism. Although the expanse, logistics, and the short time between visits constrained our analysis and interpretation, our results suggest that shorter revisit intervals may be appropriate for herbaceous compared to woody systems to track change most efficiently.
Publisher: Canadian Science Publishing
Date: 03-2014
Abstract: Shark dietary patterns can determine how they will respond to changes in prey availability and bio ersity. Geographic variation in diet can also indicate if species have unique structuring roles or feeding strategies in different environments. Unfortunately, little is known about the diet of most shark species and how diet varies over time and space. This study used stable isotope analysis to assess the diet of the Australian sharpnose shark (Rhizoprionodon taylori). Plasma and muscle δ 13 C and δ 15 N of R. taylori were compared with δ 13 C and δ 15 N baselines from multiple embayments to determine the isotopic niche, trophic position, and benthic and pelagic contributions to diet over time and space. Overall, R. taylori had a wide trophic position range and consumed prey from benthic and pelagic sources. However, there was geographic and temporal variation in trophic position and benthic and pelagic contributions. These findings indicate R. taylori is a dietary generalist, but different populations may have unique effects on distinct ecosystems. Geographic variation in diet also suggests R. taylori may be adaptive to changes in prey availability.
Publisher: Elsevier BV
Date: 02-2022
Publisher: California Digital Library (CDL)
Date: 22-11-2020
Publisher: California Digital Library (CDL)
Date: 19-04-2022
Publisher: Public Library of Science (PLoS)
Date: 22-08-2022
DOI: 10.1371/JOURNAL.PONE.0271603
Abstract: Numerous studies have analysed the relationship between C 4 plant cover and climate. However, few have examined how different C 4 taxa vary in their response to climate, or how environmental factors alter C 4 :C 3 abundance. Here we investigate (a) how proportional C 4 plant cover and richness (relative to C 3 ) responds to changes in climate and local environmental factors, and (b) if this response is consistent among families. Proportional cover and richness of C 4 species were determined at 541 one-hectare plots across Australia for 14 families. C 4 cover and richness of the most common and abundant families were regressed against climate and local parameters. C 4 richness and cover in the monocot families Poaceae and Cyperaceae increased with latitude and were strongly positively correlated with January temperatures, however C 4 Cyperaceae occupied a more restricted temperature range. Seasonal rainfall, soil pH, soil texture, and tree cover modified proportional C 4 cover in both families. Eudicot families displayed considerable variation in C 4 distribution patterns. Proportional C 4 Euphorbiaceae richness and cover were negatively correlated with increased moisture availability (i.e. high rainfall and low aridity), indicating they were more common in dry environments. Proportional C 4 Chenopodiaceae richness and cover were weakly correlated with climate and local environmental factors, including soil texture. However, the explanatory power of C 4 Chenopodiaceae models were poor, suggesting none of the factors considered in this study strongly influenced Chenopodiaceae distribution. Proportional C 4 richness and cover in Aizoaceae, Amaranthaceae, and Portulacaceae increased with latitude, suggesting C 4 cover and richness in these families increased with temperature and summer rainfall, but s le size was insufficient for regression analysis. Results demonstrate the unique relationships between different C 4 taxa and climate, and the significant modifying effects of environmental factors on C 4 distribution. Our work also revealed C 4 families will not exhibit similar responses to local perturbations or climate.
Publisher: Wiley
Date: 11-11-2021
DOI: 10.1002/ECE3.8344
Abstract: In an era of unprecedented ecological upheaval, monitoring ecosystem change at large spatial scales and over long‐time frames is an essential endeavor of effective environmental management and conservation. However, economic limitations often preclude revisiting entire monitoring networks at high frequency. We aimed here to develop a prioritization strategy for monitoring networks to select a subset of existing sites that meets the principles of complementarity and representativeness of the whole ecological reality, and maximizes ecological complementarity (species accumulation) and the spatial and environmental representativeness. We applied two well‐known approaches for conservation design, the “minimum set” and the “maximal coverage” problems, using a suite of alpha and beta bio ersity metrics. We created a novel function for the R environment that performs bio ersity metric comparisons and site prioritization on a plot‐by‐plot basis. We tested our procedures using plot data provided by the Terrestrial Ecosystem Research Network (TERN) AusPlots, an Australian long‐term monitoring network of 774 vegetation and soil monitoring plots. We selected 250 plots and 80% of the total species recorded as targets for the maximal coverage and minimum set problems, respectively. We compared the subsets selected by the different bio ersity metrics in terms of complementarity and spatial and environmental representativeness. We found that prioritization based on species turnover (i.e., iterative selection of the most dissimilar plot to a cumulative s le in terms of species replacement) maximized ecological complementarity and spatial representativeness, while also providing high environmental coverage. Species richness was an unreliable metric for spatial representation. Selection based on range‐rarity‐richness was balanced in terms of complementarity and representativeness, whereas its richness‐corrected implementation failed to capture ecological and environmental variation. Prioritization based on species turnover is desirable to cover the maximum variability of the whole network. Synthesis and applications: Our results inform monitoring design and conservation priorities, which can benefit by considering the turnover component of beta ersity in addition to univariate metrics. Our tool is computationally efficient, free, and can be readily applied to any species versus sites dataset, facilitating rapid decision‐making.
Publisher: Springer Science and Business Media LLC
Date: 04-2021
DOI: 10.1038/S41597-021-00877-Z
Abstract: The photosynthetic pathway of plants is a fundamental trait that influences terrestrial environments from the local to global level. The distribution of different photosynthetic pathways in Australia is expected to undergo a substantial shift due to climate change and rising atmospheric CO 2 however, tracking change is hindered by a lack of data on the pathways of species, as well as their distribution and relative cover within plant communities. Here we present the photosynthetic pathways for 2428 species recorded across 541 plots surveyed by Australia’s Terrestrial Ecosystem Research Network (TERN) between 2011 and 2017. This dataset was created to facilitate research exploring trends in vegetation change across Australia. Species were assigned a photosynthetic pathway using published literature and stable carbon isotope analysis of bulk tissue. The photosynthetic pathway of species can be extracted from the dataset in idually, or used in conjunction with vegetation surveys to study the occurrence and abundance of pathways across the continent. This dataset will be updated as TERN’s plot network expands and new information becomes available.
Publisher: Wiley
Date: 09-07-2020
DOI: 10.1111/BRV.12636
Publisher: California Digital Library (CDL)
Date: 24-03-2021
Publisher: Springer Science and Business Media LLC
Date: 27-04-2015
Publisher: Springer Science and Business Media LLC
Date: 22-11-2014
Publisher: American Society of Parasitologists
Date: 06-2011
DOI: 10.1645/GE-2592.1
Publisher: Wiley
Date: 07-04-2015
DOI: 10.1111/JFB.12660
Abstract: This study used stable-isotope analysis to define the nearshore regional residency and movements of the small-bodied Australian sharpnose shark Rhizoprionodon taylori. Plasma and muscle δ(13) C and δ(15) N of R. taylori were collected from across five embayments and compared with values of seagrass and plankton from each bay. Linear distances between adjacent bays ranged from 30 to 150 km. There was a positive geographic correlation between R. taylori tissue and environmental δ(13) C values. Populations with the highest tissue δ(15) N were collected from bays that had the highest environmental δ(15) N values. These results suggest that R. taylori did not forage more than 100 km away from their capture location within 6 months to 1 year. The successful application of isotope analysis to define R. taylori movement demonstrates that this technique may be used in addition to traditional methods to study the movement of sharks, even within similar habitats across regionally small spatial scales (<100 km).
Publisher: California Digital Library (CDL)
Date: 28-11-2019
Publisher: Springer Science and Business Media LLC
Date: 18-01-2018
DOI: 10.1038/S41559-017-0432-Z
Abstract: Sharks are a erse group of mobile predators that forage across varied spatial scales and have the potential to influence food web dynamics. The ecological consequences of recent declines in shark biomass may extend across broader geographic ranges if shark taxa display common behavioural traits. By tracking the original site of photosynthetic fixation of carbon atoms that were ultimately assimilated into muscle tissues of 5,394 sharks from 114 species, we identify globally consistent biogeographic traits in trophic interactions between sharks found in different habitats. We show that populations of shelf-dwelling sharks derive a substantial proportion of their carbon from regional pelagic sources, but contain in iduals that forage within additional isotopically erse local food webs, such as those supported by terrestrial plant sources, benthic production and macrophytes. In contrast, oceanic sharks seem to use carbon derived from between 30° and 50° of latitude. Global-scale compilations of stable isotope data combined with biogeochemical modelling generate hypotheses regarding animal behaviours that can be tested with other methodological approaches.
Publisher: Springer Science and Business Media LLC
Date: 05-07-2022
DOI: 10.1007/S10980-022-01476-Y
Abstract: Maps of C 3 and C 4 plant abundance and stable carbon isotope values (δ 13 C) across terrestrial landscapes are valuable tools in ecology to investigate species distribution and carbon exchange. Australia has a predominance of C 4 -plants, thus monitoring change in C 3 :C 4 cover and δ 13 C is essential to national management priorities. We applied a novel combination of field surveys and remote sensing data to create maps of C 3 and C 4 abundance in Australia, and a vegetation δ 13 C isoscape for the continent. We used vegetation and land-use rasters to categorize grid-cells (1 ha) into woody (C 3 ), native herbaceous, and herbaceous cropland (C 3 and C 4 ) cover. Field surveys and environmental factors were regressed to predict native C 4 herbaceous cover. These layers were combined and a δ 13 C mixing model was used to calculate site-averaged δ 13 C values. Seasonal rainfall, maximum summer temperature, and soil pH were the best predictors of C 4 herbaceous cover. Comparisons between predicted and observed values at field sites indicated our approach reliably predicted generalised C 3 :C 4 abundance. Southern Australia, which has cooler temperatures and winter rainfall, was dominated by C 3 vegetation and low δ 13 C values. C 4 -dominated areas included northern savannahs and grasslands. Our isoscape approach is distinct because it incorporates remote sensing products that calculate cover beneath the canopy, the influence of local factors, and extensive validation, all of which are critical to accurate predictions. Our models can be used to predict C 3 :C 4 abundance under climate change, which is expected to substantially alter current C 3 :C 4 abundance patterns.
Publisher: Public Library of Science (PLoS)
Date: 11-10-2018
Publisher: Wiley
Date: 05-2021
DOI: 10.1111/JVS.13046
Abstract: The Terrestrial Ecosystem Research Network (TERN), Australia's national land ecosystem monitoring programme, measures critical environmental attributes from local to continental scale and generates quality data for research and land management. Since 2011, TERN has performed standardised field surveys and s ling across a national plot network. At each plot, TERN records vegetation structure, composition and ersity, soil characteristics, and collects plant and soil s les for analysis. At the time of submission, TERN has established over 750 plots and performed over 1,000 plot surveys across Australia. Here we present ausplotsR , an R package for the R statistical computing environment that provides a user‐friendly interface to rapidly import, visualise, and analyse TERN plot data. Easy‐to‐use functions extract the data and compile data tables that can be incorporated into a variety of statistical analysis, most notably multivariate applications requiring plant community data with standardised relative abundances. ausplotsR includes functions to calculate useful vegetation metrics, such as species presence/absence, cover, and basal area. The package also provides information on TERN’s extensive soil and plant s le collection. We expect ausplotsR will help facilitate and advance ecological research and management throughout Australia and provide useful data for vegetation modellers globally.
Publisher: California Digital Library (CDL)
Date: 26-04-2022
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/MF13272
Abstract: Shark resource-use strategies affect how they will respond to changes within their environment and, as such, may be important to consider in conservation and management. Movement data on sharks that use nearshore areas is particularly valuable because these habitats are highly dynamic. The present study used passive acoustic telemetry to examine the space-use, habitat-selection and habitat-specialisation patterns of the Australian sharpnose shark, Rhizoprionodon taylori, in a nearshore area. Habitat selectivity and specialisation were assessed across five benthic habitat types, including outer bay, seagrass, reef, sandy inshore and intertidal mudflats. The majority of R. taylori sharks were present for short periods of time, ranging from 1 to 112 days (mean ± s.e. = 16.9 ± 4.9). Activity-space analysis indicated that R. taylori roamed widely, but monthly activity-space size was consistent among in iduals and through time. Both the population and in iduals displayed wide habitat niches, indicating that the species may be resilient to environmental change. However, R. taylori consistently selected for seagrass over other habitats, potentially for feeding. Therefore, declines in seagrass availability may reduce R. taylori presence in nearshore areas and may be relevant to spatial management of this species.
Publisher: Springer Science and Business Media LLC
Date: 09-05-2019
Publisher: Center for Open Science
Date: 14-01-2021
Abstract: Numerous studies have analysed the relationship between C4 plant cover and climate. However, few have examined how different C4 taxa vary in their response to climate, or how environmental factors alter C4:C3 abundance. Here we investigate (a) how proportional C4 plant cover and richness (relative to C3) responds to changes in climate and local environmental factors, and (b) if this response is consistent among families. Proportional cover and richness of C4 species were determined at 541 one-hectare plots across Australia for 14 families. C4 cover and richness of the most common and abundant families were regressed against climate and local parameters. C4 cover and richness in Poaceae and Cyperaceae were strongly positively correlated with January temperatures, however C4 Cyperaceae occupied a more restricted temperature range. C4 Poaceae cover was also correlated with seasonal rainfall, but no such trends were identified in Cyperaceae. Soil pH and tree cover modified relative C4 cover in these families. Proportional C4 Euphorbiaceae and Chenopodiaceae cover and richness were weakly correlated with climate, but were more strongly influenced by local environmental factors, including tree cover and soil texture. However, the explanatory power of C4 Euphorbiaceae and Chenopodiaceae models were poor. Results demonstrate the unique relationships between different C4 taxa and climate, and the significant modifying effects of environmental factors on C4 distribution. Our work also reveals C4 families will not exhibit consistent responses to perturbations in climate or local conditions. These results have substantial implications for predicting C4 cover over global, continental and regional areas. This preprint is current under review following revisions with the journal Oecologia.
No related grants have been discovered for Samantha Munroe.