2020 Seminar Series

Wednesday, 05th August 2020 | Presented by Distinguished Prof Bill Laurance |James Cook University - Cairns campus

Tropical forests, the world’s most biologically diverse ecosystems, are being felled and fragmented at rates that lack historical precedent. I will describe the dynamics and shifting composition of fragmented forests in central Amazonia, using a 40-year dataset from the Biological Dynamics of Forest Fragments Project. Surprisingly few aspects of rainforest ecology are unaffected by fragmentation. Edge effects, rare weather events and changes in the composition of modified vegetation surrounding fragments have had strong effects on fragment ecology. In general, populations and communities of species in fragments are hyperdynamic relative to nearby intact forest. The effects of fragmentation appear to interact synergistically with other anthropogenic threats such as logging, hunting, fire and large-scale climate change, creating an even greater peril for the Amazonian biota.

Watch the recording

Wednesday, 20th May 2020 | Presented by Prof John Terborgh|Duke University

Large herbivores, such as elephants, rhinos, and hippos, are known as “ecosystem engineers” for their capacity to transform vegetation. Such animals have been amply studied in savanna environments in Africa and South Asia where they can be observed and their activities quantified. But large herbivorous mammals are not restricted to open environments; they also occur in closed-canopy forests where direct observations are precluded, making their impacts difficult to study. A better understanding of the role of megaherbivores in tall forests is of more than academic interest because the ecological roles of such animals is being lost to poaching, logging, land clearing, and other human activities almost everywhere they still persist. Does the loss of large herbivores pose a threat to forest ecosystem diversity and stability? If their impacts are large, their loss could have consequences that cascade through the ecosystem, perhaps to the detriment of a broader slice of biodiversity. For the last decade, my wife, Lisa Davenport, and I have been evaluating the impacts of elephants and other large herbivores in equatorial forests in Africa (Gabon) and Asia (Malaysia). As is true in savannas, elephants and other large herbivores exert profound effects on the structure and species diversity of these forests, reducing stem counts, altering diversity in some surprising ways, and effectively eliminating whole categories of species, at least on local scales. The effect of large herbivores on plant species diversity is thus strongly negative, but in a curious twist, forests in which such animals have been extirpated experience diversity bounce-back. Is there a conservation message in this? Yes, but it has as much to do with other aspects of herbivore ecology as with their direct effects on plant species diversity. If you come to the talk, you’ll find out why.

Watch the recording

Wednesday, 13th May 2020 | Presented by Dr Tobin Northfield| Assistant Professor (WSU) and Adjunct Senior Lecturer (JCU)

Working to produce food for nearly 8 billion people globally amidst rampant evidence of a sixth mass extinction is enough to stimulate an existential crisis. Conservation biologists work to reduce the environmental impacts of food production, while agroecologists work to maximize the ecosystem services often encouraged by those same conservation activities. Unfortunately, the keys to balancing conservation and food production are likely dependent on the types of agriculture, including the environment in which it occurs and the types of ecosystem services that it depends on. Here, I will discuss the impacts of agriculture on conservation of animals such as birds and butterflies, as well as conservation activities that improve ecosystem services such as pollination and pest control. Finally, I will discuss global trends in the impacts of farm management strategies on the consistency of each, environmental impact reduction and agricultural production.

Watch the recording

Wednesday, 6th May 2020 | Presented by Prof Jeff Sayers|Adjunct Professor (JCU)

I will present our experiences of engaging in long-term research to support biodiversity conservation in a set of “Sentinel Landscapes” in Indonesia and Central Africa. This work now involves several scientists from JCU and UBC who collaborate with universities, conservation NGOs and local people in the host countries. We are working in biodiverse tropical forest areas where there are also high levels of human poverty. Land uses are changing rapidly in these areas and presenting trade-offs between improving livelihoods of the people and maintaining biodiversity. These are the frontier areas where the struggle to conserve the world’s tropical biodiversity will be won or lost. We advocate for “Transdisciplinary” research that draws upon knowledge and skills from a diversity of scientific disciplines but also engages strongly with local resource users and decision makers. We do not attempt to produce plans or blue-prints for conservation – instead we seek to “nudge” the behaviour of the people whose decisions determine the future of the landscapes. We would like to use this seminar to reinforce the collaboration between JCU, UBC and our colleagues in Indonesia.

Watch the recording

Wednesday, 29th April 2020 | Presented by Dr Ashley Field |Senior Botanist (Queensland Herbarium, Department of Environment and Science; Australian Tropical Herbarium)

Phlegmariurus is an ancient genus in the family Lycopodiaceae with a modern diversity of 250 species spread across the wet tropics, wet subtropics and wet temperate zones globally. We explore hypotheses about the biogeographic radiation, biome shifts and transitions between the epiphytic and terrestrial niches in Phlegmariurus using phylogenetic data from Sanger-sequencing and Target-sequence capture from a comprehensive global sampling. We infer that Phlegmariurus is most likely of Gondwanan origin, and that it diverged from the Laurasian Huperzia and Gondwawan Phylloglossum in the Mesozoic. Phlegmariurus has subsequently diverged into a Neotropical and Palaeotropical radiations in the Eocene, with the Neotropical radiation repeatedly dispersing both eastwards and westwards into the Palaeotropics to the present. Conversely, the Palaeotropical radiation has dispersing into the Neotropics only once. The orogenesis of the Andes is likely to have been a primary driver of the shift of Phlegmariurus back into the terrestrial niche and its subsequent hyperdiversification and local endemism in the montane Neotropics. In contrast, the Palaeotropical radiation remains predominated by epiphytes from tropical rainforests, with secondary terrestrialisation being comparatively rare and restricted to a few facultative species in the temperate zones. Long distance dispersal and specialisation within the epiphytic habitat appear to be important factors in the diversification of Phlegmariurus in the Palaeotropics with multiple dispersals reaching even the most remote forested Oceanic islands of the Pacific.

Watch the recording

Wednesday, 8th April 2020 | Presented by Dr Lisa Davenport | University of Florida

Shallow lakes possess a well-known propensity to change states in response to experimental manipulations of top predators. In most such experiments to date, the top piscivore in the system has been a fish, e. g., largemouth bass (Micropterus salmoides). However, warm temperate and tropical lakes typically support non-piscine piscivores, including mammals, birds and reptiles. The roles of these air-breathing piscivores has been little investigated and whether, individually or collectively, the consumption of fish prey by these groups exceeds that of piscine piscivores remains unknown. We report on both a longitudinal (2001 – 2018) and a cross-sectional (2012) study of the bird, caiman and giant otter populations of floodplain lakes in the Manu National Park in Peru. We compare the roles of the three groups, after removing the effects of taxonomic status and body mass, using allometric equations to estimate FMR (field metabolic rate) for each group in each lake. Giant otters emerge as the dominant piscivore in lakes that support a resident group with an energy requirement more than twice that of all piscivorous birds and more than 7 times that of caiman. However, giant otters were resident in only 8 of 27 surveyed lakes in the Río Manu Basin. Indirect evidence suggests that these 8 lakes are more productive than lakes not occupied by otters, and they are characteristically green (i.e. dominated by phytoplankton rather than submerged or floating aquatic plants). We propose that enhanced productivity of these lake ecosystems may be facilitated by the presence of otters, with an underlying 5-tiered trophic structure.

Watch the recording

Wednesday, 1st April 2020 | Presented by Dr Ariana Lambrides | Post Doctoral Research Fellow-JCU

Marine fisheries have been central to Aboriginal and Torres Strait Islander people’s connection to sea country in Queensland for millennia. Archaeological approaches are well suited to explore these human-environmental relationships across broad temporal and spatial scales, extending well beyond historical fisheries data routinely used to inform contemporary fisheries management. In recent years there has been increasing use of archaeological data-sets to inform marine resource management and food security, and importantly enhance social resilience through Indigenous community partnerships.

We undertook a meta-analysis of archaeological evidence of fish exploitation along the eastern Queensland coast to explore geographic variability in the role of fish within subsistence regimes and changes in targeted fish species through time. Results indicate the occurrence of mixed species fisheries, which were locally and regionally variable in terms of the fish species captured and habitats exploited. In some cases, an increase through time in the range of fish species targeted was reported. While resource selection was likely mediated by local ecological knowledge and cultural preferences, these outcomes importantly support existing archaeological models for the region, including documented shifts in subsistence regimes during the mid-to-late Holocene, and associated increased reliance on marine resources and expansion in diet breadth. While gaps in our knowledge remain, particularly the exploitation of islands along the length of the Great Barrier Reef, current research in partnership with traditional owners in the Lizard Island Group has returned a large fish bone assemblage. This record will provide an unparalleled opportunity to assess the dynamic role of fish and fishing practices throughout the Holocene in this region.

Watch the recording

Wednesday, 25th March 2020 | Presented by Dr Daniel Montesinos | Senior Research Fellow ATH/JCU

Ecological intensification aims to counter-balance the negative impacts of agriculture and forestry intensification by promoting management interventions that maximize ecosystem services. Ecological intensification is a knowledge intensive process that requires optimal management of nature’s ecological functions and biodiversity to improve agricultural system performance, efficiency and farmers’ and foresters’ livelihoods. This approach intends to harness the benefits of increasing ecosystem services and biodiversity in a way that maximizes production, but minimizes environmental impacts by decreasing, but not excluding, the use of synthetic fertilizers, pesticides, or energy. Ecological intensification is gaining popularity due to its down-to-earth results-based approach, and includes practices that are generally recognized as good practices in both agriculture and forestry, such as: conservation tillage, crop rotation, and mixed cropping.

Watch the recording

Wednesday, 18th March 2020 | Presented by A/Prof Paul Nelson|James Cook University

Efficient production of food entails raising nitrogen concentrations in soil and water above levels found in natural ecosystems. Some nitrogen is inevitably lost from the paddock or pond, especially in high rainfall environments. We are testing the ability of ‘denitrification bioreactors’ to remove nitrogen from water leaving sugarcane and fish farms, in a first for the tropics. We are testing various configurations of bioreactors in various situations, and testing the effects of factors such as nutrient concentration, water salinity and retention time. This talk will present interim results of the research.

Watch the recording

Wednesday, 11th March 2020 | Presented by Dr Cath Moran (ecologist, CSIRO) A/Prof Lori Lach (JCU) Mr Andrew Robinson (Earth Guardians)

How we manage for biosecurity in the Wet Tropics with a changing climate (Cath Moran):

Increasing temperatures, changing rainfall patterns, rising sea levels and higher levels of carbon dioxide in the atmosphere are changing the conditions that affect the growth and survival of invasive species. These changes benefit some invasive species and disadvantage others. It is likely that increasing climate-driven disturbance will advantage many invasive species, and powerful cyclones, widespread and intense bushfires, and frequent floods are expected to create more opportunities for pest plants and animals to invade new areas. New invasive species are also being dispersed in floodwaters, changing ocean currents and wind patterns and via human population movements. Adapting management of invasive species to the impacts of climate change will involve re-assessing the risk from introduced species under changing conditions, increasing vigilance for emerging problems and possibly re-defining our concept of what is ‘natural’

Invasive ants and climate change—what we know and what we need to know to understand future threats (Lori Lach):

When climate change and invasive species are mentioned together, it is usually in the context of predicting whether a given species would be able to establish in a given area under future climate scenarios. But abiotic suitability as it affects establishment is only one aspect of invasive species ecology that might be affected by climate change. The spread, impact, and management of invasive species will also be affected by changes to temperature and rainfall patterns. Ants are among the most formidable of invasive species, and Australia spends millions of dollars annually attempting to eradicate some of the worst. In my talk, I’ll focus on how current and predicted changes to our climate may affect ant abundance, which underpins both the spread and impact of these invaders. ’ll also describe how increased variability in seasonal weather patterns is already vexing invasive ant management programs, and, overlain with potential changes to ant biology, will make eradication or containment even more challenging. Throughout my talk, I will highlight the many gaps in our knowledge that prevent us from making strong predictions, as well as point out where there is cause for optimism.

The Role of Citizen Science in Invasive Species and Climate Change (Andrew Robinson):

As the impact of climate change increases before our eyes, established scientific practice is struggling even more to protect biodiversity and agriculture from invasive species. Institutional science, weighed down in Australia by 250 years of colonial history, lacks the necessary resource, trust and nimbleness to make meaningful, long-term change in the face of the current climate crisis. A solution lies in a transformation of scientific practice itself - something which is becoming more possible these days due to the latest developments in citizen science practice and the latest technologies being produced right here in Australia. I’ll be talking about how, if we hope to reduce the impact of invasive species and climate change in Australia, it's both necessary and easy to start moving rigorous scientific practice out of traditional science institutions and into the hands of local communities, indigenous scientists, young people and anyone who wishes to be part of saving life on Earth.

Watch the recording

Wednesday, 4th March 2020 | Presented by A/Prof Kerrylee Rogers |University of Wollongong

Abstract: Mangroves occur at the coast and will be central to any discussion regarding the implications of sea-level rise for coastal communities. As mangrove forests provide crucial ecosystem services for people in coastal communities, there is an immediate and critical need to understand and project the capacity of mangrove forests to adapt to anticipated accelerating sea-level rise. Improved access to spatial data has facilitated the application of spatial models that project changes to mangrove accommodation space with sea-level rise. Scientists presently have relatively good understanding of the behaviour of mangrove forests at millennial timescales, and processes operating at contemporary timescales. However, there is less certainty about the response of mangrove forests at decadal to century timescales. It is now time for mangrove scientists to integrate data across spatial scales and prioritise accuracy over precision when undertaking projections. These challenges are discussed in the context of lessons learnt whilst researching mangrove forests in Australia and elsewhere. This research emphasises the need for cross-disciplinary research projects and international collaboration between physical and social scientists.

Watch the recording

Wednesday, 26th February 2020 | Presented by Distinguished Professor Michael Bird|JCU

The peopling of Sahul (the combined landmass of Australia and New Guinea) represents the earliest trans-oceanic migration event in human history. Archaeological data and demographic modelling suggest that the peopling of the continent required substantial populations, occurred within a few thousand years, and encompassed environments ranging from hyper-arid deserts to temperate uplands and tropical rainforests. How this migration through an empty continent occurred, or how humans responded to the physical environment they encountered has, however, remained largely speculative. By constructing a new, fine-scale (250m resolution) digital elevation model for Sahul, coupled with a fine-scale viewshed analysis of landscape prominence for the entire continent, we developed a point process-to-network function whereby the most parsimonious routes these first people likely traversed emerge.

Out of ~125 billion created paths, our analysis revealed a small number of major pathways - super-highways - transecting the continent, validated against archaeological data, suggesting that the early Sahulians adopted a set of fundamental rules for physiological capacity, attraction to landscape features and freshwater distribution to ensure survival and success. This early continental peopling can be described by basic rules of adaptation to local landscape features, with people minimizing the likelihood of failure, even without previous experience of novel landscapes. Results demonstrate the extraordinary cultural plasticity of humans to adapt to novel and challenging environments. Our analyses provide targets for future archaeological investigation, as well as informing current policy makers planning for present day migration as a result of climate disruption, and methods to more robustly interrogate current Out-of-Africa debates.

Watch the recording