ORCID Profile
0000-0001-7103-5153
Current Organisation
UNSW Sydney
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Publisher: Wiley
Date: 28-07-2023
Abstract: The ranges of many species globally have already shifted to maintain climatic equilibrium in the face of climate change. Biocrusts—soil surface dwelling communities of lichens, bryophytes and microbes—play important functional roles in many ecosystems, particularly in drylands. Compared to better studied animal and plant taxa, dryland biocrusts have different establishment requirements and have never been assessed for historical range shifts. Here, we revisited the sites ( N = 204) of a 25‐year‐old biocrust survey across a large area (400,000 km 2 ) of drylands in south‐eastern Australia. We used quadratic models to quantify changes in the climate niches of 15 lichen, eight moss and five liverwort taxa, as well as biocrust cover and richness. Our models showed that the observed climatic niches of most taxa have become hotter and drier in the past quarter century, yet the responses of the vast majority of taxa are consistent with remaining in the same geographic space. A similar pattern was observed at the community level, where the peak of biocrust cover and richness now occurs in a hotter, drier environment. Notable exceptions were the liverwort Riccia lamellosa and lichens in the genera Cladonia and Xanthoparmelia , which showed signs of contraction at their arid range edges. Unlike more mobile taxa, most biocrust species have yet to shift geographically and may already be lagging behind the pace of climate change. One explanation for the mortality lag is that long‐term climate variability in the system is extensive, which may have selected for the ability to withstand multi‐year warm periods as long as there is an eventual return to milder conditions. However, no forecasts of future climate include a return to milder conditions, suggesting there will be an eventual loss of ecosystem multifunctionality at the contracting front. Expansion lags are most likely due to delays in the mortality of competing vascular plants. Synthesis : Our study provides a valuable contribution to the knowledge of range shifts in understudied taxa and highlights a future need to promote the expansion of biocrusts to maintain the provision of ecosystem functions and services across their range.
Publisher: California Digital Library (CDL)
Date: 22-05-2023
DOI: 10.32942/X2QS36
Abstract: When a plant is introduced to a new ecosystem it may escape from some of its coevolved herbivores. Reduced herbivore damage, and the ability of introduced plants to allocate resources from defence to growth and reproduction can increase the success of introduced species. This mechanism is known as enemy release and is known to occur in some species and situations, but not in others. Understanding the conditions under which enemy release is most likely to occur is important, as this will help us to identify which species and habitats may be most at risk of invasion. We compared in-situ measurements of herbivory on 16 plant species at 12 locations within their native European and introduced Australian ranges to quantify their level of enemy release and understand the relationship between enemy release and time, space, and climate. Overall, plants experienced approximately seven times more herbivore damage in their native range than in their introduced range. We found no evidence that enemy release was related to time since introduction, introduced range size, temperature, precipitation, humidity, or elevation. From here, we can explore whether traits such as leaf defences, or phylogenetic relatedness to neighbouring plants, are stronger indicators of enemy release across species.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 18-03-2022
Abstract: Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by s ling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale.
Publisher: Wiley
Date: 21-12-2022
Abstract: Plants lose a remarkable amount of energy to herbivorous animals, and this damage has substantial impacts on plant fitness and species' distributions. There are many ways ecologists can measure leaf damage, with some methods being more time‐consuming than others. Due to a high variance in herbivory, accurate quantification of damage at the population level requires s ling of many leaves. A simple yet effective solution to this problem is to estimate leaf damage visually. Visually estimating leaf damage may be less accurate than scanning methods, but visual estimates of leaf damage are much faster than digital measurements. Using simulations, we show that gathering larger quantities of data at a slightly higher level of inaccuracy gives a more accurate estimate of a population's overall leaf damage than fewer, exact measurements. We then introduce the ZAX Herbivory Trainer, a free online application that teaches researchers to accurately visually estimate leaf damage. On average, users took ~9 min and 48 images to complete our trainer which significantly decreased their estimate inaccuracy from 13.2% to 6%. This low level of inaccuracy can be retained up to 3 months post‐training so researchers can use the ZAX Herbivory Trainer once prior to short fieldwork or every 3 months for extensive fieldwork. We also recommend a cut‐off point, whereby if a person has not completed the app in 17.5 min or 85 images (90th percentile), they may not be suitable to estimate herbivory for research purposes. The ZAX Herbivory Trainer will allow researchers of any experience level to assess herbivory quickly and accurately in a globally standardised way. International collaborators, students and citizen scientists can all find use in this app, no matter the scale of their projects. From this we can gather better data to address big picture questions in ecology such as patterns in herbivory relating to latitude or climate change.
Publisher: The Royal Society
Date: 03-2020
Abstract: Many taxa show substantial differences in lifespan between the sexes. However, these differences are not always in the same direction. In mammals, females tend to live longer than males, while in birds, males tend to live longer than females. One possible explanation for these differences in lifespan is the unguarded X hypothesis, which suggests that the reduced or absent chromosome in the heterogametic sex (e.g. the Y chromosome in mammals and the W chromosome in birds) exposes recessive deleterious mutations on the other sex chromosome. While the unguarded X hypothesis is intuitively appealing, it had never been subject to a broad test. We compiled male and female longevity data for 229 species spanning 99 families, 38 orders and eight classes across the tree of life. Consistent with the unguarded X hypothesis, a meta-analysis showed that the homogametic sex, on average, lives 17.6% longer than the heterogametic sex. Surprisingly, we found substantial differences in lifespan dimorphism between female heterogametic species (in which the homogametic sex lives 7.1% longer) and male heterogametic species (in which the homogametic sex lives 20.9% longer). Our findings demonstrate the importance of considering chromosome morphology in addition to sexual selection and environment as potential drivers of sexual dimorphism, and advance our fundamental understanding of the mechanisms that shape an organism's lifespan.
Publisher: Wiley
Date: 04-05-2022
DOI: 10.1111/GEB.13522
Abstract: Eucalypts have a widespread global distribution owing to their popularity for agroforestry and as environmental plantings. Despite an abundance of site‐specific evidence that eucalypts modify soils and soil processes, we lack a quantitative synthesis of their overall effects at the global scale. This limits our capacity to assess the likely impacts of future introductions in any given region of the world. Global. 1986–2021. Eucalyptus , Angophora and Corymbia . We used a systematic search to derive a database of empirical data from 227 studies across 33 countries ( n effect size = 2,806) and tested three predictions about the effects of eucalypts on soil properties and whether these effects varied with plantation age and soil depth. Compared with (non‐eucalypt) native vegetation, eucalypts significantly reduced soil moisture, microbial abundance, nitrogen, cations and anions. Relative reductions in soil microbes and ions were stronger in older eucalypt plantations. A comparison of eucalypts with (non‐eucalypt) silvicultural and agropastoral systems revealed similar effects on most soil properties, although eucalypts tended to reduce potassium and enhance carbon to a greater extent than other managed systems. We found no consistent effects of eucalypts on soil pH. Our study provides the first extensive global meta‐analysis of the effects of eucalypts on soil properties and processes and demonstrates that effects are highly dependent on the community with which they are compared (i.e., natural or managed). In general, our findings reinforce the widely held belief that eucalypts deplete soil nutrients and dominate water resources. Understanding how eucalypts affect soils allows us to assess their global suitability for agroforestry, soil rehabilitation and soil carbon enhancement, while considering the potential environmental costs.
Publisher: The Royal Society
Date: 16-08-2023
Abstract: When a plant is introduced to a new ecosystem it may escape from some of its coevolved herbivores. Reduced herbivore damage, and the ability of introduced plants to allocate resources from defence to growth and reproduction can increase the success of introduced species. This mechanism is known as enemy release and is known to occur in some species and situations, but not in others. Understanding the conditions under which enemy release is most likely to occur is important, as this will help us to identify which species and habitats may be most at risk of invasion. We compared in situ measurements of herbivory on 16 plant species at 12 locations within their native European and introduced Australian ranges to quantify their level of enemy release and understand the relationship between enemy release and time, space and climate. Overall, plants experienced approximately seven times more herbivore damage in their native range than in their introduced range. We found no evidence that enemy release was related to time since introduction, introduced range size, temperature, precipitation, humidity or elevation. From here, we can explore whether traits, such as leaf defences or phylogenetic relatedness to neighbouring plants, are stronger indicators of enemy release across species.
Publisher: Springer Science and Business Media LLC
Date: 20-10-2022
No related grants have been discovered for Zoe Xirocostas.