ORCID Profile
0000-0003-4597-3343
Current Organisations
University of Canterbury
,
Universiteit Utrecht
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Publisher: Elsevier BV
Date: 11-2013
Publisher: Springer Science and Business Media LLC
Date: 22-07-2012
DOI: 10.1038/NCLIMATE1627
Publisher: Springer Science and Business Media LLC
Date: 02-07-2013
Publisher: Frontiers Media SA
Date: 04-12-2019
Publisher: CSIRO Publishing
Date: 2015
DOI: 10.1071/MF14311
Abstract: Our understanding of variation in epibiota communities remains incomplete. This study relates such variability to multiple concurrent environmental factors. Specifically we determined the relative importance of salinity, depth, wave exposure, habitat and ‘shell type’ (shell type combined species, size, morphology and mobility traits) for community structure of sessile epibiota on gastropods in the Swan River Estuary, Australia. We quantified distribution, biofouling patterns, and detailed epibiota community structures on gastropod species in the estuary – the native Nassarius pauperatus and Bedeva paiva and the invasive Batillaria australis. The invasive Batillaria was much more abundant, and more biofouled, than any of the native species, thereby supporting orders of magnitude more epibiota in the estuary. Generalised linear models were used to partition variation in richness and abundance of epibiota among the above listed factors. Of the five factors were only shell type and salinity significant in 9 of 14 models. These results highlight (1) that a single invasive species can alter epibiota communities on a large system-wide scale, (2) an overwhelming importance of shell type and salinity in explaining estuarine epibiota communities, and (3) that additional environmental factors need to be included in future studies to improve predictive models of distribution for epibiota communities.
Publisher: Springer Netherlands
Date: 2014
Publisher: Wiley
Date: 07-12-2015
DOI: 10.1111/GCB.12772
Publisher: Springer Science and Business Media LLC
Date: 11-05-2022
Publisher: Springer Science and Business Media LLC
Date: 04-03-2019
Publisher: Elsevier BV
Date: 10-2011
DOI: 10.1016/J.ENVRES.2011.05.024
Abstract: Invasive species have transformed local, regional and global biotas however, few generalities about the mechanisms driving impacts of invaders have emerged. To explain variation in impacts among studies, we propose a broad framework that separates drivers of impacts into universal and unique attributes of the invasive species and the invaded habitat. Universal attributes are relevant to all invasions whereas unique attributes are distinct to a specific invasion. For ex le, impacts associated with the abundance of any invader or the properties of a specific invader (e.g., a rare toxin) represent a universal and unique impact attribute. Through meta-analyses of aquatic field experiments, we demonstrate the utility of our framework, documenting that both the abundance and the taxonomic identity of the invader significantly influence invasion outcomes for marine and freshwater plant and animal invaders. Our review also highlights that many more experiments are needed to test for universal attributes, such as priority effects, age and size, and how the attributes of the invaded habitat further modify invasion impacts. We hope that our framework will stimulate experimental invasion ecology and begin to reconcile the idiosyncrasies that currently impede the development of a unified framework for invasion impacts.
Publisher: Elsevier BV
Date: 04-2011
Publisher: Inter-Research Science Center
Date: 29-04-2010
DOI: 10.3354/MEPS08516
Publisher: Walter de Gruyter GmbH
Date: 2004
DOI: 10.1515/BOT.2004.068
Publisher: Informa UK Limited
Date: 04-2014
DOI: 10.2216/13-197.1
Publisher: Wiley
Date: 09-2021
DOI: 10.1111/DDI.13407
Publisher: Public Library of Science (PLoS)
Date: 10-01-2012
Publisher: Wiley
Date: 07-2011
DOI: 10.1111/J.1095-8649.2011.03015.X
Abstract: In this study, fishes and habitat attributes were quantified, four times over 1 year, on three reefs within four regions encompassing a c. 6° latitudinal gradient across south-western Australia. The variability observed was partitioned at these spatio-temporal scales in relation to reef fish variables and the influence of environmental drivers quantified at local scales, i.e. at the scale of reefs (the number of small and large topographic elements, the cover of kelp, fucalean and red algae, depth and wave exposure) and at the scale of regions (mean and maximum nutrient concentrations and mean seawater temperature) with regard to the total abundance, species density, species ersity and the multivariate structure of reef fishes. Variation in reef fish species density and ersity was significant at the regional scale, whereas variation in the total abundance and assemblage structure of fishes was also significant at local scales. Spatial variation was greater than temporal variation in all cases. A systematic and gradual species turnover in assemblage structure was observed between adjacent regions across the latitudinal gradient. The cover of red algae within larger patches of brown macroalgae (a biological attribute of the reef) and the number of large topographic elements (a structural attribute of the reef) were correlated with variation observed at local scales, while seawater temperature correlated with variation at the scale of regions. In conclusion, conservation efforts on reef fishes need to incorporate processes operating at regional scales with processes that shape local reef fish communities at local scales.
Publisher: Informa UK Limited
Date: 05-09-2023
Publisher: Springer Science and Business Media LLC
Date: 09-11-2020
DOI: 10.1038/S41598-020-75445-3
Abstract: Prolonged high-temperature extreme events in the ocean, marine heatwaves, can have severe and long-lasting impacts on marine ecosystems, fisheries and associated services. This study applies a marine heatwave framework to analyse a global sea surface temperature product and identify the most extreme events, based on their intensity, duration and spatial extent. Many of these events have yet to be described in terms of their physical attributes, generation mechanisms, or ecological impacts. Our synthesis identifies commonalities between marine heatwave characteristics and seasonality, links to the El Niño-Southern Oscillation, triggering processes and impacts on ocean productivity. The most intense events preferentially occur in summer, when climatological oceanic mixed layers are shallow and winds are weak, but at a time preceding climatological maximum sea surface temperatures. Most subtropical extreme marine heatwaves were triggered by persistent atmospheric high-pressure systems and anomalously weak wind speeds, associated with increased insolation, and reduced ocean heat losses. Furthermore, the most extreme events tended to coincide with reduced chlorophyll- a concentration at low and mid-latitudes. Understanding the importance of the oceanic background state, local and remote drivers and the ocean productivity response from past events are critical steps toward improving predictions of future marine heatwaves and their impacts.
Publisher: Elsevier BV
Date: 11-2011
DOI: 10.1016/J.CUB.2011.09.028
Abstract: In recent decades, global climate change [1] has caused profound biological changes across the planet [2-6]. However, there is a great disparity in the strength of evidence among different ecosystems and between hemispheres: changes on land have been well documented through long-term studies, but similar direct evidence for impacts of warming is virtually absent from the oceans [3, 7], where only a few studies on in idual species of intertidal invertebrates, plankton, and commercially important fish in the North Atlantic and North Pacific exist. This disparity of evidence is precarious for biological conservation because of the critical role of the marine realm in regulating the Earth's environmental and ecological functions, and the associated socioeconomic well-being of humans [8]. We interrogated a database of >20,000 herbarium records of macroalgae collected in Australia since the 1940s and documented changes in communities and geographical distribution limits in both the Indian and Pacific Oceans, consistent with rapid warming over the past five decades [9, 10]. We show that continued warming might drive potentially hundreds of species toward and beyond the edge of the Australian continent where sustained retreat is impossible. The potential for global extinctions is profound considering the many endemic seaweeds and seaweed-dependent marine organisms in temperate Australia.
Publisher: Cambridge University Press
Date: 18-06-2015
Publisher: Elsevier BV
Date: 05-2010
Publisher: Springer Netherlands
Date: 2016
Publisher: Walter de Gruyter GmbH
Date: 19-01-2001
DOI: 10.1515/BOT.2001.005
Publisher: Inter-Research Science Center
Date: 29-03-2012
DOI: 10.3354/MEPS09552
Publisher: Informa UK Limited
Date: 05-2005
Publisher: Elsevier BV
Date: 04-2011
Publisher: Wiley
Date: 18-05-2010
DOI: 10.1111/J.1461-0248.2010.01466.X
Abstract: Successful mitigation of negative effects of global warming will depend on understanding the link between physiological and ecological responses of key species. We show that while metabolic adjustment may assist Australasian kelp beds to persist and maintain abundance in warmer waters, it also reduces the physiological responsiveness of kelps to perturbation, and suppresses canopy recovery from disturbances by reducing the ecological performance of kelp recruits. This provides a warning not to rely solely on inventories of distribution and abundance to evaluate ecosystem function. The erosion of resilience is mediated by a shift in adult-juvenile interactions from competitive under cool to facilitative under warm conditions, supporting the prediction that positive interactions may become increasingly important in a warmer future. Kelp beds may remain intact but with a lower threshold for where additional impacts (e.g., extreme storms or reduced water quality) will lead to persistent loss of habitat and ecological function.
Publisher: Springer Netherlands
Date: 2016
Publisher: Wiley
Date: 08-2009
DOI: 10.1111/J.1529-8817.2009.00709.X
Abstract: Invasions by nonindigenous macroalgal species (NIMS) potentially cause severe impacts on native species. We conducted a meta-analysis of 18 field-based manipulative experiments to quantify the direction and magnitude of impacts (Hedges effect size d, hereafter ES). We found significant small-to-medium negative effects on "macrophyte abundance" (cover, biomass of native taxa EScumulative = -0.30) and medium-to-large negative effects on "macrophyte assemblages" (richness, ersity, total abundance EScumulative = -0.70). In contrast, EScumulative were not significant for "macrophyte processes" (growth, mortality EScumulative = -0.39), "animal abundance" (densities EScumulative = -0.13), or "animal assemblages" (richness, ersity EScumulative = 0.75). The nonsignificant effect sizes were characterized by low s le sizes and should be interpreted with caution. Three study-specific effect sizes were particularly large (<-2.0), showing that, in specific cases, impacts can be highly negative. From a conservation perspective, focus could be on such worst-case scenarios. Still, the reported EScumulative are likely biased toward larger effects because only the most conspicuous NIMS have been tested and because nonsignificant results are less likely to be published. To better understand the impacts of NIMS, more manipulative experiments are needed, testing more species and under contrasting environmental conditions. Future studies should include procedural control treatments and report the abundance of the NIMS to avoid ambiguous interpretations. In conclusion, current experimental evidence shows that NIMS have, on average, small-to-large negative impacts on native plant species and assemblages. It is possible that these effects can result in severe consequences when accumulated over long time periods and large spatial scales.
Publisher: Wiley
Date: 26-09-2018
DOI: 10.1111/DDI.12767
Publisher: Springer Science and Business Media LLC
Date: 14-04-2020
DOI: 10.1038/S41598-020-63429-2
Abstract: The impacts invasive species have on bio ersity and ecosystem function globally have been linked to the higher abundances they often obtain in their introduced compared to native ranges. Higher abundances of invaders in the introduced range are often explained by a reduction in negative species interactions in that range, although results are equivocal. The role of positive interactions in explaining differences in the abundance of invaders between native and invasive ranges has not been tested. Using biogeographic surveys, we showed that the rocky shore porcelain crab, Petrolisthes elongatus , was ~4 times more abundant in its introduced (Tasmania, Australia) compared to its native (New Zealand) range. The habitat of these crabs in the invaded range (underside of intertidal boulders) was extensively covered with the habitat-forming tubeworm Galeolaria caespitosa . We tested whether the habitat provided by the tubeworm facilitates a higher abundance of the invasive crab by creating mimics of boulders with and without the tubeworm physical structure and measured crab colonisation into these habitats at three sites in both Tasmania and New Zealand. Adding the tubeworm structure increased crab abundance by an average of 85% across all sites in both ranges. Our intercontinental biogeographic survey and experiment demonstrate that native species can facilitate invader abundance and that positive interactions can be important drivers of invasion success.
Publisher: Springer Science and Business Media LLC
Date: 28-03-2022
Publisher: Inter-Research Science Center
Date: 13-12-2012
DOI: 10.3354/AB00471
Publisher: Springer Science and Business Media LLC
Date: 07-2003
Publisher: Wiley
Date: 05-12-2013
DOI: 10.1002/ECE3.893
Publisher: Springer Science and Business Media LLC
Date: 07-08-2009
Publisher: Springer Science and Business Media LLC
Date: 07-03-2016
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/MF09184
Abstract: Understanding patterns of species richness is a major goal for ecologists, especially in space-limited habitats where many organisms live on top of others (epibiosis, e.g. by algae growing on gastropods in marine environments). We tested the hypotheses that species richness of epiflora on the gastropod Turbo torquatus would not differ between regions with similarly rich algal floras, and that epifloral richness would increase with increasing gastropod size. Macroalgal floras of Hamelin Bay (HB), Marmion (M), Jurien Bay (JB) and Kalbarri (K), Western Australia, ranged from ∼20 to 40 species reef–1 (JB = HB = M ≥ K). Epiflora on small T. torquatus (shell area cm2) did not differ among regions but epifloral richness increased with increasing basibiont size. Large T. torquatus ( cm2) were only found in Hamelin Bay and Marmion, where epifloral richness differed substantially. Epifloral richness was positively related to basibiont size in Marmion but not in Hamelin Bay. However, densities of patellid limpets on large T. torquatus were ∼4× higher in Hamelin Bay than in Marmion, implying that limpet grazing suppresses epifloral richness. Epifloral richness on turbinids is not simply associated with regional species pools or gastropod size rather, biological interactions at the scale of in idual basibionts apparently govern broad scale patterns of epibiosis.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 08-07-2016
Abstract: Ecosystems over time have endured much disturbance, yet they tend to remain intact, a characteristic we call resilience. Though many systems have been lost and destroyed, for systems that remain physically intact, there is debate as to whether changing temperatures will result in shifts or collapses. Wernburg et al. show that extreme warming of a temperate kelp forest off Australia resulted not only in its collapse, but also in a shift in community composition that brought about an increase in herbivorous tropical fishes that prevent the reestablishment of kelp. Thus, many systems may not be resilient to the rapid climate change that we face. Science , this issue p. 169
Publisher: The Oceanography Society
Date: 06-2018
Publisher: Elsevier BV
Date: 09-2005
Publisher: Elsevier BV
Date: 09-2005
Publisher: Elsevier BV
Date: 04-2012
Publisher: Oxford University Press (OUP)
Date: 11-05-2010
DOI: 10.1093/ICB/ICQ042
Abstract: The importance of positive interactions is increasingly acknowledged in contemporary ecology. Most research has focused on direct positive effects of one species on another. However, there is recent evidence that indirect positive effects in the form of facilitation cascades can also structure species abundances and bio ersity. Here we conceptualize a specific type of facilitation cascade-the habitat cascade. The habitat cascade is defined as indirect positive effects on focal organisms mediated by successive facilitation in the form of biogenic formation or modification of habitat. Based on a literature review, we demonstrate that habitat cascades are a general phenomenon that enhances species abundance and ersity in forests, salt marshes, seagrass meadows, and seaweed beds. Habitat cascades are characterized by a hierarchy of facilitative interactions in which a basal habitat former (typically a large primary producer, e.g., a tree) creates living space for an intermediate habitat former (e.g., an epiphyte) that in turn creates living space for the focal organisms (e.g., spiders, beetles, and mites). We then present new data on a habitat cascade common to soft-bottom estuaries in which a relatively small invertebrate provides basal habitat for larger intermediate seaweeds that, in turn, generate habitat for focal invertebrates and epiphytes. We propose that indirect positive effects on focal organisms will be strongest when the intermediate habitat former is larger and different in form and function from the basal habitat former. We also discuss how humans create, modify, and destroy habitat cascades via global habitat destruction, climatic change, over-harvesting, pollution, or transfer of invasive species. Finally, we outline future directions for research that will lead to a better understanding of habitat cascades.
Publisher: Frontiers Media SA
Date: 13-12-2019
Publisher: Public Library of Science (PLoS)
Date: 08-11-2013
Publisher: Oxford University Press (OUP)
Date: 14-10-2009
Publisher: Springer Science and Business Media LLC
Date: 22-10-2005
Publisher: Springer Science and Business Media LLC
Date: 09-06-2004
Publisher: Wiley
Date: 02-03-2012
Publisher: American Association for the Advancement of Science (AAAS)
Date: 22-10-2021
Abstract: Extreme warming events in the world’s oceans are becoming more widespread and frequent 8 of the 10 most severe recorded events have taken place in the past decade. Smith et al . review how these marine heatwaves are severely altering ecosystem service provision, with widespread socioeconomic impacts. Heatwave effects, including range shifts and mass mortality of marine species and harmful algal blooms, have knock-on economic consequences that already run into billions of US dollars. As well as reviewing the impacts of these events, the authors discuss the mitigation and adaptation measures that are needed to alleviate the risks and damaging impacts. —AMS
Publisher: Springer Science and Business Media LLC
Date: 04-06-2020
Publisher: Springer Science and Business Media LLC
Date: 11-11-2008
Publisher: The Royal Society
Date: 22-02-2014
Publisher: Wiley
Date: 25-11-2010
Publisher: Springer Science and Business Media LLC
Date: 30-01-2018
DOI: 10.1038/S41598-018-20009-9
Abstract: Genetic ersity confers adaptive capacity to populations under changing conditions but its role in mediating impacts of climate change remains unresolved for most ecosystems. This lack of knowledge is particularly acute for foundation species, where impacts may cascade throughout entire ecosystems. We combined population genetics with eco-physiological and ecological field experiments to explore relationships among latitudinal patterns in genetic ersity, physiology and resilience of a kelp ecosystem to climate stress. A subsequent ‘natural experiment’ illustrated the possible influence of latitudinal patterns of genetic ersity on ecosystem vulnerability to an extreme climatic perturbation (marine heatwave). There were strong relationships between physiological versatility, ecological resilience and genetic ersity of kelp forests across latitudes, and genetic ersity consistently outperformed other explanatory variables in contributing to the response of kelp forests to the marine heatwave. Population performance and vulnerability to a severe climatic event were thus strongly related to latitudinal patterns in genetic ersity, with the heatwave extirpating forests with low genetic ersity. Where foundation species control ecological structure and function, impacts of climatic stress can cascade through the ecosystem and, consequently, genetic ersity could contribute to ecosystem vulnerability to climate change.
Publisher: Elsevier BV
Date: 09-2018
DOI: 10.1016/J.GAITPOST.2018.07.172
Abstract: Musculoskeletal models do not include patient-specific muscle forces but rely on a scaled generic model, with muscle forces left unscaled in most cases. However, to use musculoskeletal simulations to inform clinical decision-making in children with cerebral palsy (CP), inclusion of subject-specific muscle forces is of utmost importance in order to represent each child's compensation mechanisms introduced through muscle weakness. The aims of this study were to (i) evaluate if maximum isometric muscle forces (MIMF) in musculoskeletal models of children with CP can be scaled based on strength measurements obtained with a hand-held-dynamometer (HHD), (ii) evaluate the impact of the HHD based scaling approach and previously published MIMF scaling methods on computed muscle forces during gait, and (iii) compare maximum muscle forces during gait between CP and typically developing (TD) children. Strength and motion capture data of six CP and motion capture data of six TD children were collected. The HHD measurements to obtain hip, knee and ankle muscle strength were simulated in OpenSim and used to modify MIMF of the 2392-OpenSim model. These muscle forces were compared to the MIMF scaled on the child's body mass and a scaling approach, which included the body mass and muscle-tendon lengths. OpenSim was used to calculate peak muscle forces during gait. Ankle muscle strength was insufficient to reproduce joint moments during walking when MIMF were scaled based on HHD. During gait, peak hip and knee extensor muscle forces were higher and peak ankle dorsi-flexor forces were lower in CP compared to TD participants. HHD measurements can be used to scale MIMF for the hip and knee muscle groups but underestimate the force capacity of the ankle muscle groups during walking. Muscle-tendon-length and mass based scaling methods affected muscle activations but had little influence on peak muscle forces during gait.
Publisher: Regional Euro-Asian Biological Invasions Centre Oy (REABIC)
Date: 06-2008
Publisher: Springer Science and Business Media LLC
Date: 31-01-2022
DOI: 10.1038/S41467-022-28194-Y
Abstract: Habitat heterogeneity is considered a primary causal driver underpinning patterns of ersity, yet the universal role of heterogeneity in structuring bio ersity is unclear due to a lack of coordinated experiments testing its effects across geographic scales and habitat types. Furthermore, key species interactions that can enhance heterogeneity, such as facilitation cascades of foundation species, have been largely overlooked in general bio ersity models. Here, we performed 22 geographically distributed experiments in different ecosystems and biogeographical regions to assess the extent to which variation in bio ersity is explained by three axes of habitat heterogeneity: the amount of habitat, its morphological complexity, and capacity to provide ecological resources (e.g. food) within and between co-occurring foundation species. We show that positive and additive effects across the three axes of heterogeneity are common, providing a compelling mechanistic insight into the universal importance of habitat heterogeneity in promoting bio ersity via cascades of facilitative interactions. Because many aspects of habitat heterogeneity can be controlled through restoration and management interventions, our findings are directly relevant to bio ersity conservation.
Publisher: Wiley
Date: 02-2006
Publisher: Springer Science and Business Media LLC
Date: 05-03-2018
DOI: 10.1038/S41559-018-0487-5
Abstract: It has long been recognized that primary foundation species (FS), such as trees and seagrasses, enhance bio ersity. Among the species facilitated are secondary FS, including mistletoes and epiphytes. Case studies have demonstrated that secondary FS can further modify habitat-associated organisms ('inhabitants'), but their net effects remain unknown. Here we assess how inhabitants, globally, are affected by secondary FS. We extracted and calculated 2,187 abundance and 397 richness Hedges' g effect sizes from 91 and 50 publications, respectively. A weighted meta-analysis revealed that secondary FS significantly enhanced the abundance and richness of inhabitants compared to the primary FS alone. This indirect facilitation arising through sequential habitat formation was consistent across environmental and experimental conditions. Complementary unweighted analyses on log response ratios revealed that the magnitude of these effects was similar to the global average strength of direct facilitation from primary foundation species and greater than the average strength of trophic cascades, a widely recognized type of indirect facilitation arising through sequential consumption. The finding that secondary FS enhance the abundance and richness of inhabitants has important implications for understanding the mechanisms that regulate bio ersity. Integrating secondary FS into conservation practice will improve our ability to protect bio ersity and ecosystem function.
Publisher: Inter-Research Science Center
Date: 09-01-2014
DOI: 10.3354/MEPS10566
Publisher: Elsevier BV
Date: 07-2008
Publisher: Informa UK Limited
Date: 20-04-2007
Publisher: Inter-Research Science Center
Date: 09-12-2008
DOI: 10.3354/MEPS07718
Publisher: Cambridge University Press (CUP)
Date: 22-07-2020
No related grants have been discovered for Mads Thomsen.