Center for Integrative Ecology

Warrnambool, Australia

Center for Integrative Ecology

Warrnambool, Australia
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Chivers W.J.,University of Newcastle | Walne A.W.,Sir Alister Hardy Foundation for Ocean Science | Hays G.C.,Deakin University | Hays G.C.,Center for Integrative Ecology
Nature Communications | Year: 2017

The response of marine plankton to climate change is of critical importance to the oceanic food web and fish stocks. We use a 60-year ocean basin-wide data set comprising >148,000 samples to reveal huge differences in range changes associated with climate change across 35 plankton taxa. While the range of dinoflagellates and copepods tended to closely track the velocity of climate change (the rate of isotherm movement), the range of the diatoms moved much more slowly. Differences in range shifts were up to 900 km in a recent warming period, with average velocities of range movement between 7 km per decade northwards for taxa exhibiting niche plasticity and 99 km per decade for taxa exhibiting niche conservatism. The differing responses of taxa to global warming will cause spatial restructuring of the plankton ecosystem with likely consequences for grazing pressures on phytoplankton and hence for biogeochemical cycling, higher trophic levels and biodiversity. © The Author(s) 2017.


Esteban N.,University of Swansea | Mortimer J.A.,Turtle Action Group of Seychelles | Mortimer J.A.,University of Florida | Hays G.C.,Deakin University | Hays G.C.,Center for Integrative Ecology
Proceedings of the Royal Society B: Biological Sciences | Year: 2017

Estimating the absolute number of individuals in populations and their fecundity is central to understanding the ecosystem role of species and their population dynamics as well as allowing informed conservation management for endangered species. Estimates of abundance and fecundity are often difficult to obtain for rare or cryptic species. Yet, in addition, here we show for a charismatic group, sea turtles, that are neither cryptic nor rare and whose nesting is easy to observe, that the traditional approach of direct observations of nesting has likely led to a gross overestimation of the number of individuals in populations and underestimation of their fecundity. We use high-resolution GPS satellite tags to track female green turtles throughout their nesting season in the Chagos Archipelago (Indian Ocean) and assess when and where they nested. For individual turtles, nest locations were often spread over several tens of kilometres of coastline. Assessed by satellite observations, a mean of 6.0 clutches (range 2-9, s.d. = 2.2) was laid by individuals, about twice as many as previously assumed, a finding also reported in other species and ocean basins. Taken together, these findings suggest that the actual number of nesting turtles may be almost 50% less than previously assumed. © 2017 The Author(s) Published by the Royal Society. All rights reserved.


Hays G.C.,Deakin University | Hays G.C.,Center for Integrative Ecology | Mazaris A.D.,Aristotle University of Thessaloniki | Schofield G.,Deakin University | And 2 more authors.
Proceedings of the Royal Society B: Biological Sciences | Year: 2017

For species with temperature-dependent sex determination (TSD) there is the fear that rising temperatures may lead to single-sex populations and population extinction. We show that for sea turtles, a major group exhibiting TSD, these concerns are currently unfounded but may become important under extreme climate warming scenarios. We show how highly female-biased sex ratios in developing eggs translate into much more balanced operational sex ratios so that adult male numbers in populations around the world are unlikely to be limiting. Rather than reducing population viability, femalebiased offspring sex ratios may, to some extent, help population growth by increasing the number of breeding females and hence egg production. For rookeries across the world (n ¼ 75 sites for seven species), we show that extreme female-biased hatchling sex ratios do not compromise population size and are the norm, with a tendency for populations to maximize the number of female hatchlings. Only at extremely high incubation temperature does high mortality within developing clutches threaten sea turtles. Our work shows how TSD itself is a robust strategy up to a point, but eventually high mortality and female-only hatchling production will cause extinction if incubation conditions warm considerably in the future. © 2017 The Author(s) Published by the Royal Society. All rights reserved.


Jones A.R.,Australian Museum Research Institute | Schlacher T.A.,University of The Sunshine Coast | Schoeman D.S.,University of The Sunshine Coast | Schoeman D.S.,Nelson Mandela Metropolitan University | And 3 more authors.
Ocean and Coastal Management | Year: 2017

Sandy beach ecosystems have various ecocentric and anthropocentric values. These values are under multiple, increasing pressures from diverse human activities and, in particular, from the consequences of climate-change. The conservation of these values requires evidence-based policy formulation and management strategies that address societal goals such as those set by the United Nations (2012). Here, we use these goals, pressures, knowledge gaps and our combined judgement to nominate important policy- and management-orientated research questions. These are grouped under five broad topics: natural condition; protecting ecosystem health; conservation of biodiversity; sustaining ecosystem goods and services; and climate change. The last is particularly important since it threatens both services to society and the ecological integrity of beach ecosystems at great spatial and temporal scales. Further, humans are likely to respond to climate change in the urban coastal zone with large-scale engineering projects (e.g., nourishment, seawalls) which will have substantial ecological effects. The resolution of these questions should inform evidence-based policies and strategies to manage the pressures faced by ocean beaches. © 2017


Schofield G.,Deakin University | Schofield G.,Center for Integrative Ecology | Papafitsoros K.,Weierstrass Institute for Applied Analysis And Stochastics | Haughey R.,Deakin University | And 2 more authors.
Marine Ecology Progress Series | Year: 2017

Many animals invest time and energy in removing unwanted organisms from their body surface; however, the benefits of symbiotic cleaning associations to 'clients' are disputed. We used aerial (unmanned aerial vehicles, UAVs) and underwater surveys to investigate whether loggerhead sea turtles Caretta caretta actively or incidentally invested in using fish-cleaning stations at a temperate breeding area (Zakynthos, Greece), although they are expected to minimize movement to divert energy to egg development. If the former, we hypothesized that turtles would swim into the station (UAV surveys), visit multiple times and compete for access (underwater surveys). Underwater surveys showed that station location changed annually, ruling out usage of a longterm cognitive memory. UAV surveys showed that turtles began using the station immediately after mating activity decreased (mid-May), with use remaining high until females departed (July). Wind direction (primarily southerly) was correlated with the frequency of use (UAV and under - water surveys) and direction of movement through the station (from upwind to downwind); however, turtles swam actively (i.e. did not simply drift). Of the unique turtles photo-identified during underwater surveys, 25 and 18% of individuals were detected multiple times within and across surveys, respectively, with at least 2 turtles competing for access to cleaner fish in most surveys. UAV surveys showed that more turtles were present within 100 m of the station compared to the turtles detected by underwater surveys at the station, suggesting individuals may visit the station repeatedly through the day. We conclude that turtles might initially find a station incidentally; however, repeated visits and competition for access suggest that turtles receive direct (stress relief, epibiont removal) and/or indirect (health, fitness, migratory) benefits. © Inter-Research 2017.


McDonald P.G.,University of New England of Australia | McDonald P.G.,University of Wales | Rollins L.A.,Deakin University | Rollins L.A.,Center for Integrative Ecology | And 2 more authors.
Behavioral Ecology and Sociobiology | Year: 2016

Many hypotheses have been proposed to account for cooperative behaviour, with those favouring kin selection receiving the greatest support to date. However, the importance of relatedness becomes less clear in complex societies where interactions can involve both kin and non-kin. To help clarify this, we examined the relative effect of indirect versus key direct benefit hypotheses in shaping cooperative decisions. We assessed the relative importance of likely reciprocal aid (as measured by spatial proximity between participants), kin selection (using molecular-based relatedness indices) and putative signals of relatedness (vocal similarity) on helper/helper cooperative provisioning dynamics in bell miners (Manorina melanophrys), a species living in large, complex societies. Using network analysis, we quantified the extent of shared provisioning (helping at the same nests) among individual helpers (excluding breeding pairs) over three seasons and 4290 provisioning visits, and compared these with the location of individuals within a colony and networks built using either genetic molecular relatedness or call similarity indices. Significant levels of clustering were observed in networks; individuals within a cluster were more closely related to each other than other colony members, and cluster membership was stable across years. The probability of a miner helping at another’s nest was not simply a product of spatial proximity and thus the potential for reciprocal aid. Networks constructed using helping data were significantly correlated to those built using molecular data in 5 of 10 comparisons, compared to 8 of 10 comparisons for networks constructed using call similarity. This suggests an important role of kinship in shaping helping dynamics in a complex cooperative society, apparently determined via an acoustic ‘greenbeard’ signal in this system. © 2015, Springer-Verlag Berlin Heidelberg.


Cardilini A.P.A.,Deakin University | Buchanan K.L.,Deakin University | Sherman C.D.H.,Deakin University | Cassey P.,University of Adelaide | Symonds M.R.E.,Center for Integrative Ecology
Oecologia | Year: 2016

The capacity of non-native species to undergo rapid adaptive change provides opportunities to research contemporary evolution through natural experiments. This capacity is particularly true when considering ecogeographical rules, to which non-native species have been shown to conform within relatively short periods of time. Ecogeographical rules explain predictable spatial patterns of morphology, physiology, life history and behaviour. We tested whether Australian populations of non-native starling, Sturnus vulgaris, introduced to the country approximately 150 years ago, exhibited predicted environmental clines in body size, appendage size and heart size (Bergmann’s, Allen’s and Hesse’s rules, respectively). Adult starlings (n = 411) were collected from 28 localities from across eastern Australia from 2011 to 2012. Linear models were constructed to examine the relationships between morphology and local environment. Patterns of variation in body mass and bill surface area were consistent with Bergmann’s and Allen’s rules, respectively (small body size and larger bill size in warmer climates), with maximum summer temperature being a strongly weighted predictor of both variables. In the only intraspecific test of Hesse’s rule in birds to date, we found no evidence to support the idea that relative heart size will be larger in individuals which live in colder climates. Our study does provide evidence that maximum temperature is a strong driver of morphological adaptation for starlings in Australia. The changes in morphology presented here demonstrate the potential for avian species to make rapid adaptive changes in relation to a changing climate to ameliorate the effects of heat stress. © 2016 Springer-Verlag Berlin Heidelberg


McLeod E.M.,Victoria University of Melbourne | Guay P.-J.,Victoria University of Melbourne | Taysom A.J.,Victoria University of Melbourne | Robinson R.W.,Victoria University of Melbourne | Weston M.A.,Center for Integrative Ecology
PLoS ONE | Year: 2013

One way to manage disturbance to waterbirds in natural areas where humans require access is to promote the occurrence of stimuli for which birds tolerate closer approaches, and so cause fewer responses. We conducted 730 experimental approaches to 39 species of waterbird, using five stimulus types (single walker, three walkers, bicycle, car and bus) selected to mimic different human management options available for a controlled access, Ramsar-listed wetland. Across species, where differences existed (56% of 25 cases), motor vehicles always evoked shorter flight-initiation distances (FID) than humans on foot. The influence of stimulus type on FID varied across four species for which enough data were available for complete cross-stimulus analysis. All four varied FID in relation to stimuli, differing in 4 to 7 of 10 possible comparisons. Where differences occurred, the effect size was generally modest, suggesting that managing stimulus type (e.g. by requiring people to use vehicles) may have species-specific, modest benefits, at least for the waterbirds we studied. However, different stimulus types have different capacities to reduce the frequency of disturbance (i.e. by carrying more people) and vary in their capacity to travel around important habitat. © 2013 McLeod et al.


Ekanayake K.B.,Deakin University | Ekanayake K.B.,Center for Integrative Ecology | Sutherland D.R.,Phillip Island Nature Parks | Dann P.,Phillip Island Nature Parks | And 2 more authors.
Wildlife Research | Year: 2015

Context Egg depredation is a major cause of reproductive failure among birds and can drive population declines. In this study we investigate predatory behaviour of a corvid (little raven; Corvus mellori) that has only recently emerged, leading to widespread and intense depredation of eggs of a burrow-nesting seabird (little penguin; Eudyptula minor). Aims The main objective of this study was to measure the rate of penguin egg depredation by ravens to determine potential threat severity. We also examined whether penguin burrow characteristics were associated with the risk of egg depredation. Ravens generally employ two modes of predatory behaviour when attacking penguin nests; thus we examined whether burrow characteristics were associated with these modes of attack. Methods Remote-sensing cameras were deployed on penguin burrows to determine egg predation rates. Burrow measurements, including burrow entrance and tunnel characteristics, were measured at the time of camera deployment. Key results Overall, clutches in 61% of monitored burrows (n≤203) were depredated by ravens, the only predator detected by camera traps. Analysis of burrow characteristics revealed two distinct types of burrows, only one of which was associated with egg depredation by ravens. Clutches depredated by ravens had burrows with wider and higher entrances, thinner soil or vegetation layer above the egg chamber, shorter and curved tunnels and greater areas of bare ground and whitewash near entrances. In addition, 86% were covered by bower spinach (Tetragonia implexicoma), through which ravens could excavate. Ravens used two modes to access the eggs: they attacked through the entrance (25% of burrow attacks, n≤124); or dug a hole through the burrow roof (75% of attacks, n≤124). Burrows that were subject to attack through the entrance had significantly shorter tunnels than burrows accessed through the roof. Conclusions The high rates of clutch loss recorded here highlight the need for population viability analysis of penguins to assess the effect of egg predation on population growth rates. Implications The subterranean foraging niche of a corvid described here may have implications for burrow-nesting species worldwide because many corvid populations are increasing, and they exhibit great capacity to adopt new foraging strategies to exploit novel prey. Journal compilation © CSIRO 2015.


PubMed | Center for Integrative Ecology and Victoria University of Melbourne
Type: Journal Article | Journal: PloS one | Year: 2013

One way to manage disturbance to waterbirds in natural areas where humans require access is to promote the occurrence of stimuli for which birds tolerate closer approaches, and so cause fewer responses. We conducted 730 experimental approaches to 39 species of waterbird, using five stimulus types (single walker, three walkers, bicycle, car and bus) selected to mimic different human management options available for a controlled access, Ramsar-listed wetland. Across species, where differences existed (56% of 25 cases), motor vehicles always evoked shorter flight-initiation distances (FID) than humans on foot. The influence of stimulus type on FID varied across four species for which enough data were available for complete cross-stimulus analysis. All four varied FID in relation to stimuli, differing in 4 to 7 of 10 possible comparisons. Where differences occurred, the effect size was generally modest, suggesting that managing stimulus type (e.g. by requiring people to use vehicles) may have species-specific, modest benefits, at least for the waterbirds we studied. However, different stimulus types have different capacities to reduce the frequency of disturbance (i.e. by carrying more people) and vary in their capacity to travel around important habitat.

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