CIE Spotlight: Ecological research questions to inform policy and the management of sandy beaches

Authors: Alan R. Jones, Thomas A. Schlacher, David S. Schoeman, Michael A. Weston, Geoffrey M. Withycombe

Source: Ocean & Coastal Management

Brief summary of the paper: 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.

CIE Spotlight: Effects of invasion history on physiological responses to immune system activation in invasive Australian cane toads

Authors: Daniel Selechnik​, Andrea J. West, Gregory P. Brown, Kerry V. Fanson, BriAnne Addison, Lee A. Rollins, Richard Shine

Source: PeerJ

Brief summary of the paper: 

The cane toad (Rhinella marina) has undergone rapid evolution during its invasion of tropical Australia. Toads from invasion front populations (in Western Australia) have been reported to exhibit a stronger baseline phagocytic immune response than do conspecifics from range core populations (in Queensland). To explore this difference, we injected wild-caught toads from both areas with the experimental antigen lipopolysaccharide (LPS, to mimic bacterial infection) and measured whole-blood phagocytosis. Because the hypothalamic-pituitary-adrenal axis is stimulated by infection (and may influence immune responses), we measured glucocorticoid response through urinary corticosterone levels. Relative to injection of a control (phosphate-buffered saline), LPS injection increased both phagocytosis and the proportion of neutrophils in the blood. However, responses were similar in toads from both populations. This null result may reflect the ubiquity of bacterial risks across the toad’s invaded range; utilization of this immune pathway may not have altered during the process of invasion. LPS injection also induced a reduction in urinary corticosterone levels, perhaps as a result of chronic stress.

CIE Spotlight: Climate change and temperature-linked hatchling mortality at a globally important sea turtle nesting site

Authors: Jacques-Olivier Laloë, Jacquie Cozens, Berta Renom, Albert Taxonera, Graeme C. Hays

Source: Global Change Biology

Brief summary of the paper: The study of temperature-dependent sex determination (TSD) in vertebrates has attracted major scientific interest. Recently, concerns for species with TSD in a warming world have increased because imbalanced sex ratios could potentially threaten population viability. In contrast, relatively little attention has been given to the direct effects of increased temperatures on successful embryonic development. Using 6603 days of sand temperature data recorded across 6 years at a globally important loggerhead sea turtle rookery—the Cape Verde Islands—we show the effects of warming incubation temperatures on the survival of hatchlings in nests. Incorporating published data (n = 110 data points for three species across 12 sites globally), we show the generality of relationships between hatchling mortality and incubation temperature and hence the broad applicability of our findings to sea turtles in general. We use a mechanistic approach supplemented by empirical data to consider the linked effects of warming temperatures on hatchling output and on sex ratios for these species that exhibit TSD. Our results show that higher temperatures increase the natural growth rate of the population as more females are produced. As a result, we project that numbers of nests at this globally important site will increase by approximately 30% by the year 2100. However, as incubation temperatures near lethal levels, the natural growth rate of the population decreases and the long-term survival of this turtle population is threatened. Our results highlight concerns for species with TSD in a warming world and underline the need for research to extend from a focus on temperature-dependent sex determination to a focus on temperature-linked hatchling mortalities.

CIE Spotlight: Seasonal reproductive tactics: annual timing and the capital-to-income breeder continuum

Authors: Cory T. Williams, Marcel Klaassen, Brian M. Barnes, C. Loren Buck, Walter Arnold, Sylvain Giroud, Sebastian G. Vetter, Thomas Ruf

Source: Philosophical Transactions of the Royal Society B: Biological Sciences

Brief summary of the paper: Tactics of resource use for reproduction are an important feature of life-history strategies. A distinction is made between ‘capital’ breeders, which finance reproduction using stored energy, and ‘income’ breeders, which pay for reproduction using concurrent energy intake. In reality, vertebrates use a continuum of capital-to-income tactics, and, for many species, the allocation of capital towards reproduction is a plastic trait. Here, we review how trophic interactions and the timing of life-history events are influenced by tactics of resource use in birds and mammals. We first examine how plasticity in the allocation of capital towards reproduction is linked to phenological flexibility via interactions between endocrine/neuroendocrine control systems and the sensory circuits that detect changes in endogenous state, and environmental cues. We then describe the ecological drivers of reproductive timing in species that vary in the degree to which they finance reproduction using capital. Capital can be used either as a mechanism to facilitate temporal synchrony between energy supply and demand or as a means of lessening the need for synchrony. Within many species, an individual’s ability to cope with environmental change may be more tightly linked to plasticity in resource allocation than to absolute position on the capital-to-income breeder continuum.

CIE Spotlight: Managing the Risks of Sea Lice Transmission Between Salmon Aquaculture and Wild Pink Salmon Fishery

Authors: Biao Huang, Charles Perrings

Source: Ecological Economics

Brief summary of the paper: A common external effect of aquaculture is the transmission of infectious diseases to wild fish stocks. A frequently cited example of this is the infection of wild salmon by sea lice from salmon farms. Management of the disease risk to wild salmon populations requires an understanding both of the disease transmission mechanisms and the control incentives faced by fish farmers. In this paper we develop a bioeconomic model that integrates sea lice population dynamics, fish population dynamics, aquaculture, and wild capture salmon fisheries. Using an optimal control framework, we investigate options for managing the sea lice infection externality. We pay particular attention to the role of sea lice management on the stability of wild stocks, and the sensitivity of sea lice effects on wild fisheries. We find that the stability of wild stocks is related to sea-lice-induced mortality (inversely) and the value of wild fishery.

CIE Spotlight: The impact of burial on the survival and recovery of the subtidal seagrass Zostera nigricaulis

Authors: A.J. Hirst, S. McGain, G.P. Jenkins

Source: Aquatic Botany

Brief summary of the paper: Many seagrass beds are exposed to environmental stresses from waves, dune migration, bioturbation and storms that lead to burial events. The impact of burial on the subtidal seagrass Zostera nigricaulis growing in Port Phillip Bay, south-eastern Australia, was examined through experimental manipulation of sediment burial height (6.25, 12.5, 25, 50 and 100% of canopy height) in the field over 14 days. The seagrass Z. nigricaulis withstood burial up to a depth of 12.5% canopy height (2 cm burial), but suffered significant reduction in seagrass biomass between 41 and 68% when buried at 25–50% canopy height (4–8 cm burial). We attributed this pattern to the presence of a modified vertical, wiry stem that allows Z. nigricaulis to tolerate low levels of burial. However, above 25% canopy height, sediment increasingly covers areas of photosynthetic leaf tissue resulting in increasing and significant levels of mortality. In a separate experiment, recovery following burial at 100% canopy height was assessed by analyzing changes in seagrass cover, maximum leaf length and canopy height during high and low growth periods. Seagrass failed to recover fully following burial after 30 weeks during winter/spring and showed no sign of recovery 6–8 weeks after burial during summer/autumn (after which the loss of the seagrass bed made interpretation difficult). The results indicate that the tolerance of Z. nigricaulis to burial is greater than other Zostera species, most likely because the vertical rhizome (wiry stem) characteristic of this species offers a degree of resilience to burial.

CIE Spotlight: Costs of immune responses are related to host body size and lifespan

Authors: Amber J. Brace, Marc J. Lajeunesse, Daniel R. Ardia, Dana M. Hawley, James S. Adelman, Katherine L. Buchanan, Jeanne M. Fair, Jennifer L. Grindstaff, Kevin D. Matson, Lynn B. Martin

Source: Ecological and Integrative Physiology

Brief summary of the paper: A central assumption in ecological immunology is that immune responses are costly, with costs manifesting directly (e.g., increases in metabolic rate and increased amino acid usage) or as tradeoffs with other life processes (e.g., reduced growth and reproductive success). Across taxa, host longevity, timing of maturity, and reproductive effort affect the organization of immune systems. It is reasonable, therefore, to expect that these and related factors should also affect immune activation costs. Specifically, species that spread their breeding efforts over a long lifetime should experience lower immune costs than those that mature and breed quickly and die comparatively early. Likewise, body mass should affect immune costs, as body size affects the extent to which hosts are exposed to parasites as well as how hosts can combat infections (via its effects on metabolic rates and other factors). Here, we used phylogenetic meta-regression to reveal that, in general, animals incur costs of immune activation, but small species that are relatively long-lived incur the largest costs. These patterns probably arise because of the relative need for defense when infection risk is comparatively high and fitness can only be realized over a comparatively long period. However, given the diversity of species considered here and the overall modest effects of body mass and life history on immune costs, much more research is necessary before generalizations are appropriate.

PhD position to study the coastal protection services provided by coastal ecosystems in south eastern Australia

Please click here for full project details and the application process.

This project will: 1) employ field techniques to estimate and monitor wave and erosion reduction through vegetated coastal ecosystems, and 2) incorporate remote sensing and land use data to quantify and map the avoided erosion and storm surge reduction services of these ecosystems in south eastern Australia. This project will provide key information for industry project partners and coastal zone managers in coastal risk assessment and management in south eastern Australia.

Project partners: Deakin University, The Nature Conservancy, Department of Environment Land Water and Planning, Parks Victoria, New South Wales Department of Primary Industries

Value: AUD$26,681 per annum tax free, project support (incl. computer, travel) plus other benefits: http://www.deakin.edu.au/courses/scholarships/find-a-scholarship/rtp-and-duprs

Supervisory team: The project is supervised by academics from Deakin University (A/Prof. Peter Macreadie, Dr Clare Duncan, Dr Paul Carnell, A/Prof. Daniel Ierodiaconou, and Dr Emily Nicholson).

Closing date: The position will remain open until filled. A first assessment of applications will be conducted in late December 2017

CIE Spotlight: Feeding the world’s largest fish: highly variable whale shark residency patterns at a provisioning site in the Philippines

Authors: Jordan A. Thomson, Gonzalo Araujo, Jessica Labaja, Emer McCoy, Ryan Murray, Alessandro Ponzo

Source: Royal Society Open Science

Brief summary of the paper: Provisioning wildlife for tourism is a controversial yet widespread practice. We analysed the residency patterns of juvenile whale sharks (Rhincodon typus) in Oslob, Philippines, where provisioning has facilitated a large shark-watching operation since 2011. We identified 208 individual sharks over three years, with an average of 18.6 (s.d. = 7.8, range = 6–43) individuals sighted per week. Weekly shark abundance varied seasonally and peak-season abundance (approx. May–November) increased across years. Whale sharks displayed diverse individual site visitation patterns ranging from a single visit to sporadic visits, seasonal residency and year-round residency. Nine individuals became year-round residents, which represents a clear response to provisioning. The timing of the seasonal peak at Oslob did not align with known non-provisioned seasonal aggregations elsewhere in the Philippines, which could suggest that seasonal residents at Oslob exploit this food source when prey availability at alternative sites is low. Since prolonged residency equates to less time foraging naturally, provisioning could influence foraging success, alter distributions and lead to dependency in later life stages. Such impacts must be carefully weighed against the benefits of provisioning (i.e. tourism revenue in a remote community) to facilitate informed management decisions.

CIE Spotlight: Shifting public values and what they mean for increasing democracy in wildlife management decisions

 

Authors: Lily M. van Eeden, Chris R. Dickman, Euan G. RitchieThomas M. Newsome

Source: Biodiversity and Conservation

Brief summary of the paper: Over the last century, changing public attitudes about the value of wildlife have triggered substantial changes in species management that have both benefited and hindered conservation efforts. Understanding and integrating contemporary public values is therefore critical for effective conservation outcomes. Using historic and contemporary examples, we highlight how public attitudes—expressed through the media and campaigns—are shaping the management of introduced and native species, as values shift towards animal welfare and mutualism. We focus on the issue of deliberate human-caused killing of wildlife, because protests against such management have disrupted traditional political and management structures that favoured eradication of wildlife across many jurisdictions and ecological contexts. In doing so, we show that it is essential to work with multiple stakeholder interest groups to ensure that wildlife management is informed by science, while also supported by public values. Achieving this hinges on appropriate science communication to build a better-informed public because management decisions are becoming increasingly democratised.