Listen to Margie Mayfield talk about her research into plant communities

Listen to the podcast from Margie Mayfield’s seminar on 17 April about plant communities in a changing world.

The Environment Institute’s Global Ecology Laboratory presented Dr Margie Mayfield, Senior Lecturer in Plant Ecology at the University of Queensland on Wednesday 17 April 2013. Her research broadly focuses on how plant and insect communities reassemble, persist and function following human land-use change.

ABSTRACT

Human activities are increasingly driving the development of novel plant communities worldwide. These stable mixes of resident native, range-expanded native and exotic plant species have become more common than most truly “natural” plant communities in many areas. Interestingly, novel communities are often interspersed with much more severally degraded communities (all exotics) and areas that support largely native communities. This begs the question, why do novel communities form in some places but not others? Despite the increasing commonality of novel communities and their potential role in conservation, we have a poor understanding of how these communities differ from those they replace and what drives and prevents their assembly. Identifying drivers of novel community development is increasingly important for many conservation and restoration efforts. In this talk I will discuss the theoretical expectations of how we expect communities to change in response large-scale environmental change and what processes should mediate where and when native-dominated communities should be resilient or susceptible to novel community development. I will then discuss several of the projects coming out of my lab looking at novel community assembly in the York Gum woodlands of SW Western Australia, where my group has been studying the mechanisms of novel community assembly over the last several years. Specifically, I will discuss the role of biotic interactions in mediating community wide responses to land use change and species invasions across environmental gradients.

Download the podcast from this seminar.

 

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New paper: Spatial and temporal predictions of inter-decadal trends in Indian Ocean whale sharks

A new paper involving Environment Institute member Corey Bradshaw has recently been published in the journal Marine Ecology Progress Series.

The paper, titled Spatial and temporal predictions of inter-decadal trends in Indian Ocean whale sharks, examines the movement patterns of whale sharks in the Indian Ocean and the effect of climate variations on sightings.

ABSTRACT

Image: Whale Shark, coutesy of KAZ2.0/Flickr

The processes driving temporal distribution and abundance patterns of whale sharks Rhincodon typus remain largely unexplained. We present an analysis of whale shark occurrence in the western Indian Ocean, incorporating both spatial and temporal elements. We tested the hypothesis that the average sighting probability of sharks has not changed over nearly 2 decades, and evaluated whether variance in sightings can be partially explained by climate signals. We used a 17 yr dataset (1991 to 2007, autumn only) of whale shark observations recorded in the logbooks of tuna purse-seiners. We randomly generated pseudo-absences and applied sequential generalized linear mixed-effects models within a multi-model information-theoretic framework, accounting for sampling effort and random annual variation, to evaluate the relative importance of temporal and climatic predictors to sighting probability. After accounting for seasonal patterns in distribution, we found evidence that sighting probability increased slightly in the first half of the sampling interval (1991−2000) and decreased thereafter (2000−2007). The model including a spatial predictor of occurrence, fishing effort, time2 and a random spatial effect explained ~60% of the deviance in sighting probability. After including climatic predictors, we found that sighting probability increased slightly with rising temperature in the central Pacific Ocean and reduced temperatures in the Indian Ocean. The declining phase of the peak, concurrent with recent accounts of declines in population size at near-shore aggregations and with the most pronounced global warming, deserves continued investigation. Teasing apart the legacy effects of past exploitation and those arising from on-going climate changes will be a major challenge for the successful long term management of the species.

Visit Inter-Research Science Centre to find out more.

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Biosecurity: Climate change and environmental uncertainty

Climate change, extreme weather events and increasing habitat modification are acting together to have a detrimental effect on the range and spread of animal pests, weeds and pathogens in Australia. Coupled with this, increasing human population size, shifting demographics and changing land-use is straining the environment. This pressure complicates pest management and dramatically increases the risk of multi-species diseases occurring.

Experts currently believe that the majority of emerging diseases are of a multi-species, or zoonotic, nature, meaning they are transferred from animals to humans. Powerful examples of zoonotic diseases include; rabies, plague and a variety of intestinal parasites.

This type of biosecurity threat has been featured in the news recently after a large proportion of Asian tiger mosquitoes were discovered in northern Queensland. This breed of mosquito can carry diseases such as dengue fever and yellow fever and poses a threat to the Australian public.

By investigating the timing and magnitude of the tropical mosquito population decision-makers can determine the optimal level of mosquito control to reduce the risk of disease outbreaks in human populations. For example in 2009, Environment Institute members Professor Barry Brook and Professor Corey Bradshaw conducted a study which investigated the mosquito population in northern Australia. They suggested that targeted control, such as spraying in early September, of mosquito breeding areas may allow for more effective control of mosquitoes close to human settlement, and therefore reduce the likelihood of disease outbreaks amongst humans.

Environment Institute member Associate Professor Phillip Cassey, an expert in biosecurity, believes that Australia needs to take notice of the research at the forefront of developing climate-change forecasting methods. This type of research can downscale data from global climate material to a scale that is ecologically beneficial for Australia.

Using climate and ecological data, Professor Cassey believes it is vitally important that Australia looks to:

• Develop user-friendly simulations to predict responses, and changes in distribution, of existing invasive species, emergence of new invasive ‘sleeper’ species, and the spread and transmission of diseases in Australia under likely scenarios of climate change and habitat modification.
• Contribute specialist expertise in information technologies such as, the use of remote sensing in combination with current data and models to identify and monitor for emerging diseases and habitat pests.
• Investigate the adoption of current techniques for tracking changes in mating systems, increasing genetic diversity, or shifts in gene patterns that could indicate the imminent risk of shifting from a ‘sleeper’ pest or weed to a problematic invasive species.

Find out more about the work of Assoc. Prof. Phillip Cassey and his team at the Cassey Invasion Ecology Group

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New Paper: Using census data and history to assess evolution and population

Salvador Herrando-Pérez

A new paper titled ‘Strength of density feedback in census data increases from slow to fast life histories‘ investigates the idea that examining the life history of species through the collection of census data can provide an evolutionary signal. According to the research this data can provide valuable feedback regarding evolution and long-term population trends.

The paper involves Environment Institute members Salvador Herrando-Pérez, Dr Steven Delean, Barry Brook and Corey Bradshaw (also of the South Australian Research and Development Institute) and has been published in Ecology and Evolution.

Download the paper to read about their findings

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New Paper: Avoiding a biodiversity collapse in tropical forest areas

Please visit senior author Corey Bradshaw’s blog

A new paper titled ‘Averting a biodiversity collapse in tropical forest protected areas‘ investigates the plight of the protected tropical reserves around the planet. The researchers argue that while most tropical reserves were helping with protection of their forest, approximately half were struggling to maintain their original biodiversity. The researchers say that a better job needs to be done defending the protected areas.

The paper featuring Environment Institute member Corey Bradshaw as a senior author, along with over 200 researchers from around the world, has been published in Nature. The lead author of paper is William Laurance (James Cook University).

Download the paper to read about their findings

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New Report: A stock assessment and future management report on the Australian Sardine

Professor Bronwyn Gillanders

A new report titled ‘Movement patterns and stock structure of Australian sardine, Sardinops sagax, off South Australia and the East Coast: implications for future stock assessment and management‘ helps to determine the structure and movement of sardines off South Australia and the east coast of Australia to provide advice to stakeholders. By analysing the facts relevant stakeholders and the industry can decide on the future of the Australian Sardine.

The report involving Environment Institute members Bronwyn Gillanders, Dr Christopher Izzo (also of South Australian Research and Development Institute) as well as Tim Ward (South Australian Research and Development Institute) has been published in SARDI Research Report Series.

Download the paper to read about their findings

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New Paper: Identification through DNA Barcoding – a powerful oppurtunity for ecologists

Professor Corey Bradshaw

A new paper titlted ‘Identification of Rays through DNA Barcoding: An Application for Ecologists‘ investiges DNA barcoding and its use as a potentially powerful ecological tool to support and confirm species identifications and to highlight species complexities. DNA Barcoding is used to investigate tropical rays as part of the ecological study.

The paper involves Environment Institute member Corey Bradshaw as well as Florencia Cerutti-Pereyra (Charles Darwin University), Mark Meekan (Australian Institute of Marine Science), Nu-Wei Wei (Charles Darwin University), Owen O’Shea (Murdoch University), Chris Austin (School of Science Monash University Sunway Campus) and has been published in PLoS ONE.

Download the paper to read about their findings

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New Paper: Anthropogenic landscape change promotes asymmetric dispersal and limits regional patch occupancy in a spatially structured bird population

Professor Andrew Lowe

A new paper involving Environment Institute member Andrew Lowe as well as David Pavlacky Jr (University of Queensland), Hugh Possingham (University of Queensland), Peter Prentis (Queensland University of Technology), David Green (Simon Fraser University) and Anne Goldizen (University of Queensland) has been published in the Journal of Animal Ecology.

The paper titled ‘Anthropogenic landscape change promotes asymmetric dispersal and limits regional patch occupancy in a spatially structured bird population‘ investigates using patch occupancy surveys and molecular data for a rainforest bird, the logrunner (Orthonyx temminckii), to determine (i) the effects of landscape change and patch structure on local extinction; (ii) the asymmetry of emigration and immigration rates; (iii) the relative influence of local and between-population landscapes on asymmetric emigration and immigration; and (iv) the relative contributions of habitat loss to asymmetric emigration and immigration.

Download the paper to read about their findings

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New Paper: Climatic effects on the growth of a temperate reef fish from the Southern Hemisphere: a biochronological approach

Professor Bronwyn Gillanders

A new paper involving Environment Institute member Bronwyn Gillanders as well as Bryan Black (Oregon State University), Dr Mark Meekan (Australian Institute of Marine Science) and Mark Morrison (National Institute of Water and Atmospheric Research Ltd) has been published in Marine Biology.

The paper titled ‘Climatic effects on the growth of a temperate reef fish from the Southern Hemisphere: a biochronological approach‘  illustrates how otolith chronologies provide quality records of annual growth patterns over decadal time scales that can be useful for forecasting the likely effects of climate change on marine ecosystems.

Download the paper to read about their findings

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New Paper: High-Resolution Coproecology: Using Coprolites to Reconstruct the Habits and Habitats of New Zealand’s Extinct Upland Moa (Megalapteryx didinus)

Alan Cooper

A new paper involving Environment Institute members Nicolas Rawlence and Alan Cooper as well as Jamie Wood,  Janet Wilmshurst, Steven Wagstaff (all of Landcare Research, New Zealand) and Trevor Worthy (University of New South Wales) has been published in PLoS ONE.

The paper titled ‘High-Resolution Coproecology: Using Coprolites to Reconstruct the Habits and Habitats of New Zealand’s Extinct Upland Moa (Megalapteryx didinus)‘ investigates the diet and ecology of extinct herbivores and its important implications for understanding the evolution of plant defence structures, establishing the influences of herbivory on past plant community structure and composition, and identifying pollination and seed dispersal syndromes.

Download the paper to read about their findings

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