ORCID Profile
0000-0002-9739-3204
Current Organisations
The University of Newcastle
,
University of Melbourne
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Publisher: Springer Science and Business Media LLC
Date: 04-07-2023
DOI: 10.1007/S10592-023-01541-2
Abstract: Targeted gene flow is an emerging conservation approach which involves introducing a cohort of in iduals with particular traits to locations where they can produce a conservation benefit. This technique is being proposed to adapt recipient populations to a known threat, but questions remain surrounding how best to maximize conservation outcomes during periods of continuous directional environmental change. Here we introduce a new management objective—to keep the recipient population extant and with maximum ersity of local alleles—and we explore how varying the timing and size of an introduction can maximise this objective. Our results reveal a trade-off between keeping a population extant and maintaining a high level of genetic ersity, but management levers can often optimize this so that nearly 100% of the allelic ersity is preserved. These optimum outcomes sets are highly sensitive to the predicted rate of environmental shift, as well as the level of outbreeding depression in the system.
Publisher: Wiley
Date: 10-2021
DOI: 10.1002/BES2.1921
Publisher: Wiley
Date: 03-06-2021
DOI: 10.1002/ECY.3363
Abstract: The arrival of novel predators can trigger trophic cascades driven by shifts in prey numbers. Predators also elicit behavioral change in prey populations, via phenotypic plasticity and/or rapid evolution, and such changes may also contribute to trophic cascades. Here, we document rapid demographic and behavioral changes in populations of a prey species (grassland melomys Melomys burtoni , a granivorous rodent) following the introduction of a novel marsupial predator (northern quoll Dasyurus hallucatus ). Within months of quolls appearing, populations of melomys exhibited reduced survival and population declines relative to control populations. Quoll‐invaded populations were also significantly shyer than nearby, quoll‐free populations of conspecifics. This rapid but generalized response to a novel threat was replaced over the following 2 yr with more threat‐specific antipredator behaviors (i.e., predator‐scent aversion). Predator‐exposed populations, however, remained more neophobic than predator‐free populations throughout the study. These behavioral responses manifested rapidly in changed rates of seed predation by melomys across treatments. Quoll‐invaded melomys populations exhibited lower per‐capita seed take rates, and rapidly developed an avoidance of seeds associated with quoll scent, with discrimination playing out over a spatial scale of tens of meters. Presumably the significant and novel predation pressure induced by quolls drove melomys populations to fine‐tune behavioral responses to be more predator specific through time. These behavioral shifts could reflect in idual plasticity (phenotypic flexibility) in behavior or may be adaptive shifts from natural selection imposed by quoll predation. Our study provides a rare insight into the rapid ecological and behavioral shifts enacted by prey to mitigate the impacts of a novel predator and shows that trophic cascades can be strongly influenced by behavioral as well as numerical responses.
Publisher: Wiley
Date: 06-07-2016
Publisher: Wiley
Date: 29-06-2022
DOI: 10.1111/GEB.13554
Abstract: Megafire plays a crucial role in driving the distribution of bio ersity around the world. Long‐term monitoring is vital for understanding how species are impacted immediately by megafire and subsequently respond over time. However, monitoring should be designed with sufficient statistical power to detect impact and recovery. In this study, we developed a simulation framework for optimizing the design of bio ersity monitoring programmes to detect population recoveries after megafire. Victoria, Australia. 2019–2020. Vertebrates. We collated species distribution models for 45 priority vertebrates most likely to respond to management after the 2019–2020 megafires in Victoria, Australia. We combined these models with fire severity maps to optimize the location of monitoring sites in and around the fire footprint. We simulated the impact of the megafires on species distributions and modelled plausible recoveries over the next 10 years. Using estimates of detectability for a suite of preferred s ling methods, we simulated monitoring at pairs of burnt and unburnt sites to evaluate the statistical power to detect the modelled recoveries. We tested the sensitivity of power to alternative monitoring designs, rates of recovery and monitoring budgets. Priority regions to establish monitoring sites varied by taxonomic group. Power to detect population recoveries increased as the monitoring budget increased, as the recovery rate increased and when the proportion of sites in burnt compared with unburnt habitat increased. According to the optimal monitoring design, an AUD $9M budget could detect 90% of recoveries to pre‐fire levels in 40% of species with % power. Power was highest for mammals, followed by birds, reptiles and hibians. Our simulation approach allowed us to test the relative performance of alternative post‐fire monitoring designs ahead of time. Although we focused on megafire, our approach could easily be applied to detect population recoveries after any large‐scale catastrophic disturbance.
Publisher: Authorea, Inc.
Date: 30-11-2020
DOI: 10.22541/AU.160670704.43226299/V1
Abstract: Targeted gene flow is an emerging conservation tool which involves introducing a cohort of in iduals with particular traits to locations where they can produce a conservation benefit. This approach is being proposed to adapt recipient populations to a known threat, but questions remain surrounding how best to maximize conservation outcomes during periods of continuous directional environmental change. Here we introduce a new management objective — to keep the recipient population extant and with maximum ersity of local alleles — and we explore how varying the timing and size of an introduction can achieve this. Our results reveal that management levers can often optimize this so that nearly 100% of the allelic ersity is preserved. These optimum outcome sets are robust to the shape of the environmental change but are highly sensitive to the the maximum magnitude of change and the level of outbreeding depression in the system.
Publisher: Elsevier BV
Date: 06-2022
Publisher: Cold Spring Harbor Laboratory
Date: 27-11-2019
DOI: 10.1101/856997
Abstract: The arrival of novel predators can trigger trophic cascades driven by shifts in prey numbers. Predators also elicit behavioural change in prey populations, via phenotypic plasticity and/or rapid evolution, and such changes may also contribute to trophic cascades. Here we document rapid demographic and behavioural changes in populations of a prey species (grassland melomys Melomys burtoni , a granivorous rodent) following the introduction of a novel marsupial predator (northern quoll Dasyurus hallucatus ). Within months of quolls appearing, populations of melomys exhibited reduced survival and population declines relative to control populations. Quoll-invaded populations ( n = 4) were also significantly shyer than nearby, quoll-free populations ( n = 3) of conspecifics. This rapid but generalised response to a novel threat was replaced over the following two years with more threat-specific antipredator behaviours (i.e. predator-scent aversion). Predator-exposed populations, however, remained more neophobic than predator-free populations throughout the study. These behavioural responses manifested rapidly in avoidance of seeds associated with quoll scent, with discrimination playing out over a spatial scale of tens of metres. Presumably the significant and novel predation pressure induced by quolls drove melomys populations to fine-tune behavioural responses to be more predator-specific through time. These behavioural shifts could reflect in idual plasticity (phenotypic flexibility) in behaviour or may be adaptive shifts from natural selection imposed by quoll predation. Our study provides a rare insight into the rapid ecological and behavioural shifts enacted by prey to mitigate the impacts of a novel predator and shows that trophic cascades can be strongly influenced by behavioural changed rates of seed predation by melomys across treatments. Quoll-invaded melomys populations exhibited lower per-capita seed take rates, and rapidly developed an as well as numerical responses.
Publisher: Wiley
Date: 10-2015
DOI: 10.1890/14-1751.1
Abstract: Effective management of alien species requires detecting populations in the early stages of invasion. Environmental DNA (eDNA) s ling can detect aquatic species at relatively low densities, but few studies have directly compared detection probabilities of eDNA s ling with those of traditional s ling methods. We compare the ability of a traditional s ling technique (bottle trapping) and eDNA to detect a recently established invader, the smooth newt Lissotriton vulgaris vulgaris, at seven field sites in Melbourne, Australia. Over a four-month period, per-trap detection probabilities ranged from 0.01 to 0.26 among sites where L. v. vulgaris was detected, whereas per-s le eDNA estimates were much higher (0.29-1.0). Detection probabilities of both methods varied temporally (across days and months), but temporal variation appeared to be uncorrelated between methods. Only estimates of spatial variation were strongly correlated across the two s ling techniques. Environmental variables (water depth, rainfall, ambient temperature) were not clearly correlated with detection probabilities estimated via trapping, whereas eDNA detection probabilities were negatively correlated with water depth, possibly reflecting higher eDNA concentrations at lower water levels. Our findings demonstrate that eDNA s ling can be an order of magnitude more sensitive than traditional methods, and illustrate that traditional- and eDNA-based surveys can provide independent information on species distributions when occupancy surveys are conducted over short timescales.
Publisher: Cold Spring Harbor Laboratory
Date: 12-06-2018
DOI: 10.1101/344796
Abstract: Islands are increasingly used to protect endangered populations from the negative impacts of invasive species. Quarantine efforts are particularly likely to be undervalued in circumstances where a failure incurs non-economic costs. One approach to ascribe value to such efforts is by modeling the expense of restoring a system to its former state. Using field-based removal experiments on two very different islands off northern Australia separated by 400 km, we estimate cane toad densities, detection probabilities, and the resulting effort needed to eradicate toads from an island, and use these estimates to examine the financial benefit of cane toad quarantine across offshore islands prioritized for conversation management by the Australian federal government. We calculate density as animals per km of freshwater shoreline, and find striking concordance of density across our two island study sites: a mean density of 353 [286, 446] in idual toads per kilometer on one island, and a density of 366 [319, 343] on the second. Detection probability differed between the two islands. Using a removal model and the financial costs incurred during toad removal, we estimate that eradicating cane toads would, on average, cost between $9444 (based on Horan Island high detectability) and $18093 AUD (Indian Island low detectability) per km of available freshwater shoreline. Across islands that have been prioritized for conservation benefit within the toads’ predicted range, we provide an estimate of the value of toad quarantine on each island, and estimate the net value of quarantine efforts to be between $27.25 – $52.20 Million AUD. We explore a proposed mainland cane toad containment strategy – to prevent the spread of cane toads into the Pilbara Bioregion, and estimate its potential value to be between $33.79 – $64.74 M AUD. Synthesis and applications . We present a modelling framework that can be used to estimate the value of preventative management, via estimating the length and cost of an eradication program. Our analyses suggest that there is substantial economic value in cane toad quarantine efforts across Australian offshore islands and a proposed mainland toad containment strategy.
Publisher: Springer Science and Business Media LLC
Date: 20-10-2020
Publisher: Springer Science and Business Media LLC
Date: 22-05-2015
Publisher: Pensoft Publishers
Date: 10-2020
DOI: 10.3897/NEOBIOTA.60.34941
Abstract: Islands are increasingly used to protect endangered populations from the negative impacts of invasive species. Quarantine efforts on islands are likely to be undervalued in circumstances in which a failure incurs non-economic costs. One approach to ascribe monetary value to such efforts is by modeling the expense of restoring a system to its former state. Using field-based removal experiments on two different islands off northern Australia separated by & 400 km, we estimate cane toad densities, detection probabilities, and the resulting effort needed to eradicate toads from an island. We use these estimates to conservatively evaluate the financial benefit of cane toad quarantine across offshore islands prioritized for conservation management by the Australian federal government. We calculate density as animals per km of freshwater shoreline, and find striking concordance of density estimates across our two island study sites: a mean density of 352 [289, 466] adult toads per kilometre on one island, and a density of 341 [298, 390] on the second. Detection probability differed between our two study islands (Horan Island: 0.1 [0.07, 0.13] Indian Island: 0.27 [0.22, 0.33]). Using a removal model and the financial costs incurred during toad removal, we estimate that eradicating cane toads would, on average, cost between $22 487 [$14 691, $34 480] (based on Horan Island) and $39 724 [$22 069, $64 001] AUD (Indian Island) per km of available freshwater shoreline. We estimate the remaining value of toad quarantine across islands that have been prioritized for conservation benefit within the toads’ predicted range, and find the net value of quarantine efforts to be $43.4 [28.4–66.6] – $76.7 [42.6–123.6] M depending on which island dataset is used to calibrate the model. We conservatively estimate the potential value of a mainland cane toad containment strategy – to prevent the spread of toads into the Pilbara Bioregion – to be $80 [52.6–123.4] – $142 [79.0–229.0] M. We present a modeling framework that can be used to estimate the value of preventative management, via estimating the length and cost of an eradication program. Our analyses suggest that there is substantial economic value in cane toad quarantine efforts across Australian offshore islands and in a proposed mainland containment strategy.
No related grants have been discovered for Adam Smart.