CIE Spotlight: Accelerometers can measure total and activity-specific energy expenditures in free-ranging marine mammals only if linked to time-activity budgets

John A.

Authors: Jeanniard-du-Dot, Tiphaine; Guinet, Christophe; Arnould, John P. Y.; Speakman, John R.; Trites, Andrew W.

Source: FUNCTIONAL ECOLOGY, 31 (2):377-386, FEB 2017

Brief summary of the paper: Energy expenditure is an important component of foraging ecology, but is extremely difficult to estimate in free-ranging animals and depends on how animals partition their time between different activities during foraging. Acceleration data have emerged as a new way to determine energy expenditure at a fine scale but this needs to be tested and validated in wild animals.

This study investigated whether vectorial dynamic body acceleration (VeDBA) could accurately predict the energy expended by marine predators during a full foraging trip. We also aimed to determine whether the accuracy of predictions of energy expenditure derived from acceleration increased when partitioned by different types of at-sea activities (i.e. diving, transiting, resting and surface activities).

To do so, we equipped 20 lactating northern (Callorhinus ursinus) and 20 lactating Antarctic fur seals (Arctocephalus gazella) with GPS, time-depth recorders and tri-axial accelerometers and obtained estimates of field metabolic rates using the doubly labelled water (DLW) method. VeDBA was derived from tri-axial acceleration, and at-sea activities (diving, transiting, resting and surface activities) were determined using dive depth, tri-axial acceleration and travelling speed.

We found that VeDBA did not accurately predict the total energy expended by fur seals during their full foraging trips (R2 = 0·36). However, the accuracy of VeDBA as a predictor of total energy expenditure increased significantly when foraging trips were partitioned by activity and when activity-specific VeDBA was paired with time-activity budgets (R2 = 0·70). Activity-specific VeDBA also accurately predicted the energy expenditures of each activity independent of each other (R2 > 0·85).

Our study confirms that acceleration is a promising way to estimate energy expenditures of free-ranging marine mammals at a fine scale never attained before. However, it shows that it needs to be based on the time-activity budgets that make up foraging trips rather than being derived as a single measure of VeDBA applied to entire foraging trips. Our activity-based method provides a cost-effective means to accurately calculate energy expenditures of fur seals using acceleration and time-activity budgets, that can be transfered to studies on other species.

 

 

CIE Seminar Series 2017 – Surprises from space: evolutionary insights from spatial reasoning

SPEAKER: Dr Ben Phillips, ARC Future Fellow, School of BioSciences, Faculty of Science, University of Melbourne

DATE: Friday, 18th August 2017
LOCATION: Geelong Campus at Waurn Ponds- room ka4.207
TIME: 1:30pm

Seminar will also be video linked to the following campuses: Melbourne Campus at Burwood – Burwood Corporate Centre (attendees-please report to reception for room details on the day); and Warrnambool Campus, Room J2.22

External visitors – wish to join us and connect to our seminars?
External parties may connect to the live seminar via *N SEBE VMP LES Seminars 52236958@deakin.edu.au [ID.36958] via the methods listed below:

  • For external guests, you can connect as a web guest by clicking HERE. If using Chrome you it will prompt you to install the Cisco Jaba Plugin, then it will prompt you to download the extension which you will need to install. Once this has been installed, you will have a black screen with a call button. You will just need to click call and it should connect into the VMP.
  • For Deakin staff and students, please join via Skype for Business (Lync) – if you have office installed you may already have Skype for business or Lync installed. You just need to look for it on the start menu. If you find it, you can log into skype using your Deakin email and password and then dial 36958.
  • Could not log in? More info on how to connect is available HERE or HERE.
  • Please note that connection is only available while a seminar is taking place.

As a courtesy, we request that when connecting to the seminar that you mute your microphone unless you are required to speak, this would ensure that the sound from the speaker to the audience is not disrupted by feedback from your microphone – thank you!

ABSTRACT: This is a homily to the role of space in evolution, in three parts.  First I will look at expanding range edges and use the cane toad system to explore the evolutionary implications of range advance.  Second, I will look at geographic variation in a much more stable system.  Using data from climate-relevant traits of a rainforest lizard, I will argue that we can use spatial reasoning to identify when geographic variation is caused by local adaptation (as opposed to plasticity).  Finally, I will head back to the toad system to float an adventurous idea for how we might use evolution to stop their invasion.

BIO: Ben Phillips spent most of the last 12 years working across northern Australia on a range of evolutionary and ecological questions.  Ben has worked on toads, snakes, mammals, beetles, and even simulated organisms. He is particularly interested in how spatial processes change evolutionary and ecological dynamics.  Ben is an ARC Future Fellow and a Senior Lecturer in the School of BioSciences.

Appointments with guest speaker may be made via lee.rollins@deakin.edu.au.

CIE Spotlight: Deimatism: a neglected component of antipredator defence

John E.

Authors: Umbers, Kate D. L.; De Bona, Sebastiano; White, Thomas E.; Lehtonen, Jussi; Mappes, Johanna; Endler, John A.

Source: BIOLOGY LETTERS, 13 (4), APR 2017

Brief summary of the paper: Deimatic or ‘startle’ displays cause a receiver to recoil reflexively in response to a sudden change in sensory input.

Deimatism is sometimes implicitly treated as a form of aposematism (unprofitability associated with a signal). However, the fundamental difference is, in order to provide protection, deimatism does not require a predator to have any learned or innate aversion. Instead, deimatism can confer a survival advantage by exploiting existing neural mechanisms in a way that releases a reflexive response in the predator.

We discuss the differences among deimatism, aposematism, and forms of mimicry, and their ecological and evolutionary implications. We highlight outstanding questions critical to progress in understanding deimatism.

CIE Spotlight: A Global Assessment of the Chemical Recalcitrance of Seagrass Tissues: Implications for Long-Term Carbon Sequestration

Stacey T. T. and Peter M.

Authors: Trevathan-Tackett, Stacey M.; Macreadie, Peter I.; Sanderman, Jonathan; Baldock, Jeff; Howes, Johanna M.; Ralph, Peter J.

Source: FRONTIERS IN PLANT SCIENCE, 8, JUN 13 2017

Brief summary of the paper: Seagrass ecosystems have recently been identified for their role in climate change mitigation due to their globally-significant carbon sinks; yet, the capacity of seagrasses to sequester carbon has been shown to vary greatly among seagrass ecosystems. The recalcitrant nature of seagrass tissues, or the resistance to degradation back into carbon dioxide, is one aspect thought to influence sediment carbon stocks.

In this study, a global survey investigated how the macromolecular chemistry of seagrass leaves, sheaths/stems, rhizomes and roots varied across 23 species from 16 countries. The goal was to understand how this seagrass chemistry might influence the capacity of seagrasses to contribute to sediment carbon stocks.

Three non-destructive analytical chemical analyses were used to investigate seagrass chemistry: thermogravimetric analysis (TGA) and solid state 13C-NMR and infrared spectroscopy. A strong latitudinal influence on carbon quality was found, whereby temperate seagrasses contained 5% relatively more labile carbon, and tropical seagrasses contained 3% relatively more refractory carbon. Sheath/stem tissues significantly varied across taxa, with larger morphologies typically containing more refractory carbon than smaller morphologies.

Rhizomes were characterized by a higher proportion of labile carbon (16% of total organic matter compared to 8–10% in other tissues); however, high rhizome biomass production and slower remineralization in anoxic sediments will likely enhance these below-ground tissues’ contributions to long-term carbon stocks.

Our study provides a standardized and global dataset on seagrass carbon quality across tissue types, taxa and geography that can be incorporated in carbon sequestration and storage models as well as ecosystem valuation and management strategies.

CIE Spotlight: Permian-Triassic boundary microbialites at Zuodeng Section, Guangxi Province, South China: Geobiology and palaeoceanographic implications

Mao L.

Authors: Fang, Yuheng; Chen, Zhong-Qiang; Kershaw, Stephen; Yang, Hao; Luo, Mao

Source: GLOBAL AND PLANETARY CHANGE, 152 115-128, MAY 2017

Brief summary of the paper: A previously unknown microbialite bed in the Permian–Triassic (P–Tr) boundary beds of Zuodeng section, Tiandong County, Guangxi, South China comprises a thin (5 cm maximum thickness) stromatolite in the lower part and the remaining 6 m is thrombolite.

The Zuodeng microbialite has a pronounced irregular contact between the latest Permian bioclastic limestone and microbialite, as in other sites in the region. The stromatolite comprises low-relief columnar and broad domal geometries, containing faint laminations. The thrombolite displays an irregular mixture of sparitic dark coloured altered microbial fabric and light coloured interstitial sediment in polished blocks.

Abundant microproblematic calcimicrobe structures identified here as Gakhumella are preserved in dark coloured laminated areas of the stromatolite and sparitic areas in thrombolites (i.e. the calcimicrobial part, not the interstitial sediment) and are orientated perpendicular to stromatolitic laminae. Each Gakhumella individual has densely arranged segments, which form a column- to fan-shaped structure.

Single segments are arch-shaped and form a thin chamber between segments. Gakhumella individuals in the stromatolite and thrombolite are slightly different from each other, but are readily distinguished from the Gakhumella– and Renalcis-like fossils reported from other P–Tr boundary microbialites in having a smaller size, unbranching columns and densely arranged, arch-shaped segments. Renalcids usually possess a larger body size and branching, lobate outlines. Filament sheath aggregates are also observed in the stromatolite and they are all orientated in one direction. Both Gakhumella and filament sheath aggregates may be photosynthetic algae, which may have played an important role in constructing the Zuodeng microbialites.

Other calcimicrobes in the Zuodeng microbialite are spheroids, of which a total of five morphological types are recognized from both stromatolite and thrombolite: (1) sparry calcite spheroid without outer sheaths, (2) a large sparry calcite nucleus coated with a thin sparry calcite sheath, (3) a large nucleus of micrite framboid aggregates rimmed by a thin sparry calcite sheath (bacterial clump-like spheroids), (4) a large nucleus of micrite framboid aggregates coated with a thin micritic sheath, and (5) a small sparry nuclei rimmed by coarse-grained, radiated euhedral rays.

The irregular contact beneath the Zuodeng microbialites is interpreted as a subaerial exposure surface due to regional regression in South China. The demise of the Zuodeng microbialites may have been due to rapid rise in sea-level because they grew in relatively shallow marine conditions and are overlain by muddy limestones containing pelagic conodonts. Also siliciclastic content increases above the microbialite, suggesting a possible climate-related increase in weathering as the transgression progressed.

CIE Spotlight: Dietary flexibility in small carnivores: a case study on the endangered northern quoll, Dasyurus hallucatus

Pic by Wildlife Explorer (Picasa Web Albums)

Authors: Dunlop, Judy A.; Rayner, Kelly; Doherty, Tim S.

Source: JOURNAL OF MAMMALOGY, 98 (3):858-866, MAY 29 2017

Brief summary of the paper: The endangered northern quoll (Dasyurus hallucatus) is a predatory marsupial with a wide and disjointed distribution across northern Australia. The disjunct Pilbara population occurs in a uniquely arid area, and faces different threatening processes to populations elsewhere.

To better understand the ecology of this small carnivore, we undertook a dietary analysis of 498 scats collected across ~100,000 km2. We calculated dietary composition and niche breadth and modeled these against biogeophysical factors (latitude, longitude, rainfall, elevation, and distance to coast) for 10 study landscapes.

We also conducted pairwise comparisons of diet groups to evaluate regional dietary differences. Quolls were highly omnivorous, consuming at least 23 species of vertebrates (mammals, birds, reptiles, frogs), as well as arthropods, molluscs, fruit, and carrion.

Diet varied widely across the region, with up to 3-fold differences in dietary niche breadth between study landscapes. We found few clear environmental drivers of the diet of D. hallucatus. The most frequently consumed food type was insects, but their occurrence in diets decreased as that of rodents and vegetation increased, indicating potential dietary preferences.

The broad and variable diet of D. hallucatus indicates opportunism similar to that of other small carnivores. Given this broad dietary niche, conservation managers will need a priori knowledge of local prey abundance if they are to accurately predict the composition of D. hallucatus diets.

Australian Science Superheroes – Euan Ritchie

“During National Science Week in August 2016, Australia’s Chief Scientist launched the #5ScientistPledge to recognise Australian Scientists. Now, we’re shining a light on some of these Australian science superheroes with a new tag – #AusScienceHeroes.”

 

Our own Dr Euan Ritchie was featured as a Science Superhero and you can read the full profile here!

CIE Spotlight: Global patterns in mangrove soil carbon stocks and losses

Paul C., Carolyn E. and Peter M.

Authors: Trisha B. Atwood, Rod M. Connolly, Hanan Almahasheer, Paul E. Carnell, Carlos M. Duarte, Carolyn J. Ewers Lewis, Xabier Irigoien, Jeffrey J. Kelleway, Paul S. Lavery, Peter I. Macreadie, Oscar Serrano, Christian J. Sanders, Isaac Santos, Andrew D. L. Steven & Catherine E. Lovelock

Source: Nature Climate Change 7, 523–528 (Published online 26 June 2017)

Brief summary of the paper: Mangrove soils represent a large sink for otherwise rapidly recycled carbon (C). However, widespread deforestation threatens the preservation of this important C stock. It is therefore imperative that global patterns in mangrove soil C stocks and their susceptibility to remineralization are understood.

Here, we present patterns in mangrove soil C stocks across hemispheres, latitudes, countries and mangrove community compositions, and estimate potential annual CO2 emissions for countries where mangroves occur. Global potential CO2 emissions from soils as a result of mangrove loss were estimated to be ~7.0TgCO2eyr−1. Countries with the highest potential CO2 emissions from soils are Indonesia (3,410GgCO2eyr−1) and Malaysia (1,288GgCO2eyr−1).

The patterns described serve as a baseline by which countries can assess their mangrove soil C stocks and potential emissions from mangrove deforestation.

CIE Seminar Series 2017 – Island eradications: prioritisations, bioindicators and ecosystem monitoring

SPEAKER: Dr Justine Shaw, Research Fellow, Centre for Biodiversity and Conservation Science, University of Queensland

DATE: Friday, 11th August 2017
LOCATION: Melbourne Campus at Burwood – Burwood Corporate Centre (attendees-please report to reception for room details on the day)
TIME: 1:30pm
Seminar will also be video linked to the following campuses: Geelong Campus at Waurn Ponds – room ka4.207; and Warrnambool Campus – room J2.22

External visitors – wish to join us and connect to our seminars?
External parties may connect to the live seminar via *N SEBE VMP LES Seminars 52236958@deakin.edu.au [ID.36958] via the methods listed below:

  • For external guests, you can connect as a web guest by clicking HERE. If using Chrome you it will prompt you to install the Cisco Jaba Plugin, then it will prompt you to download the extension which you will need to install. Once this has been installed, you will have a black screen with a call button. You will just need to click call and it should connect into the VMP.
  • For Deakin staff and students, please join via Skype for Business (Lync) – if you have office installed you may already have Skype for business or Lync installed. You just need to look for it on the start menu. If you find it, you can log into skype using your Deakin email and password and then dial 36958.
  • Could not log in? More info on how to connect is available HERE or HERE.
  • Please note that connection is only available while a seminar is taking place.

As a courtesy, we request that when connecting to the seminar that you mute your microphone unless you are required to speak, this would ensure that the sound from the speaker to the audience is not disrupted by feedback from your microphone – thank you!

ABSTRACT: Island eradications are becoming more common and more successful. Pest eradications have been undertaken on over 700 islands globally. More and more species are benefitting from these conservation actions. As technological abilities increase, decision science and ecosystem monitoring need to expand and improve to effectively implement large-scale and complex island management. I will present some of my recent work on prioritizing actions for islands, principally “which island do we choose, and what do we target?” I’ll summarize some preliminary findings on island prioritizations involving multiple target species across hundreds of islands.

Once projects have been chosen and successfully implemented we are then faced with evaluating their efficacy in restoring ecosystem structure and function.  Our recent work on Macquarie Island is a good example of this process, where we are utilizing existing long-term datasets (some over 30 years old) and are undertaking new fieldwork. We’ve identified sites, species and environmental parameters for tracking ecosystem change into the future including habitat recovery and prey switching following rabbit, cat, mouse and rat eradication. I’ll highlight one of our biggest challenges in this work – how to address shifting baselines and their role in monitoring large scale conservation projects. Human-induced ecological change spans much longer periods of time than most formal monitoring data. Therefore, to understand the magnitude and dynamics of past ecosystem change, we need to seek data on past change from alternative sources.

BIO: Justine Shaw is a Research Fellow at the Centre for Biodiversity and Conservation Science, The University of Queensland. Her research focus is the conservation of island ecosystems and terrestrial Antarctica. Justine is interested in understanding the way in which species interact with each other and their role in ecosystem function. She is currently examining the risks posed by non-native species to Antarctic protected areas, examining the interactions between indigenous and non-native species and investigating how invasive species influence island ecosystems, in particular the impacts on threatened species. Her research focuses on informing management.  She is interested in ways of dealing with ecosystem uncertainty in large scale eradication attempts.  Justine has been working on sub-Antarctic islands for 19 years.  Her current research is funded through the National Environmental Science Program, Threatened Species Recovery Hub.

Appointments with guest speaker may be made via Tim Doherty.

 

 

CIE Spotlight: Activity-specific metabolic rates for diving, transiting, and resting at sea can be estimated from time-activity budgets in free-ranging marine mammals

John A.

Authors: Jeanniard-du-Dot, Tiphaine; Trites, Andrew W.; Arnould, John P. Y.; Speakman, John R.; Guinet, Christophe

Source: ECOLOGY AND EVOLUTION, 7 (9):2969-2976, MAY 2017

Brief summary of the paper: Time and energy are the two most important currencies in animal bioenergetics. How much time animals spend engaged in different activities with specific energetic costs ultimately defines their likelihood of surviving and successfully reproducing. However, it is extremely difficult to determine the energetic costs of independent activities for free-ranging animals.

In this study, we developed a new method to calculate activity-specific metabolic rates, and applied it to female fur seals. We attached biologgers (that recorded GPS locations, depth profiles, and triaxial acceleration) to 12 northern (Callorhinus ursinus) and 13 Antarctic fur seals (Arctocephalus gazella), and used a hierarchical decision tree algorithm to determine time allocation between diving, transiting, resting, and performing slow movements at the surface (grooming, etc.).

We concomitantly measured the total energy expenditure using the doubly-labelled water method. We used a general least-square model to establish the relationship between time–activity budgets and the total energy spent by each individual during their foraging trip to predict activity-specific metabolic rates.

Results show that both species allocated similar time to diving (~29%), transiting to and from their foraging grounds (~26–30%), and resting (~8–11%). However, Antarctic fur seals spent significantly more time grooming and moving slowly at the surface than northern fur seals (36% vs. 29%). Diving was the most expensive activity (~30 MJ/day if done non-stop for 24 hr), followed by transiting at the surface (~21 MJ/day). Interestingly, metabolic rates were similar between species while on land or while slowly moving at the surface (~13 MJ/ day). Overall, the average field metabolic rate was ~20 MJ/day (for all activities combined).

The method we developed to calculate activity-specific metabolic rates can be applied to terrestrial and marine species to determine the energetic costs of daily activities, as well as to predict the energetic consequences for animals forced to change their time allocations in response to environmental shifts.