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Morris and Letnic 2017 Removal of an apex predator initiates a trophic cascade that extends from herbivores to vegetation and the soil nutrient pool

Abstract: It is widely assumed that organisms at low trophic levels, particularly microbes and plants, are essential to basic services in ecosystems, such as nutrient cycling. In theory, apex predators' effects on ecosystems could extend to nutrient cycling and the soil nutrient pool by influencing the intensity and spatial organization of herbivory. Here, we take advantage of a long-term manipulation of dingo abundance across Australia's dingo-proof fence in the Strzelecki Desert to investigate the effects that removal of an apex predator has on herbivore abundance, vegetation and the soil nutrient pool. Results showed that kangaroos were more abundant where dingoes were rare, and effects of kangaroo exclusion on vegetation, and total carbon, total nitrogen and available phosphorus in the soil were marked where dingoes were rare, but negligible where dingoes were common. By showing that a trophic cascade resulting from an apex predator's lethal effects on herbivores extends to the soil nutrient pool, we demonstrate a hitherto unappreciated pathway via which predators can influence nutrient dynamics. A key implication of our study is the vast spatial scale across which apex predators' effects on herbivore populations operate and, in turn, effects on the soil nutrient pool and ecosystem productivity could become manifest.

Jordan et al. 2017 A conservation assessment of Suricata suricatta.
Callaghan et al. 2017 A probable Australian White Ibis Threskiornis moluccus × Straw-necked Ibis T. spinicollis hybrid

Abstract. We observed a probable juvenile Australian White Ibis Threskiornis moluccus × Straw-necked Ibis T. spinicollis hybrid on the Lachlan River catchment, New South Wales, in November 2016. Photographs, combined with observations, demonstrate phenotypic characteristics of both these ibis species. The bird had a pattern on the wing similar to the Australian White Ibis but coloration on the body similar to the Straw-necked Ibis. To our knowledge, this is only the second report of a probable hybrid between these two species in the wild, and the first report documented with photographs.

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Kingsford et al. 2017 Continental impacts of water development on waterbirds, contrasting two Australian river basins: Global implications for sustainable water use


The world’s freshwater biotas are declining in diversity, range and abundance, morethan in other realms, with human appropriation of water. Despite considerable dataon the distribution of dams and their hydrological effects on river systems, there arefew expansive and long analyses of impacts on freshwater biota. We investigatedtrends in waterbird communities over 32 years, (1983–2014), at three spatial scales intwo similarly sized large river basins, with contrasting levels of water resource devel-opment, representing almost a third (29%) of Australia: the Murray–Darling Basin andthe Lake Eyre Basin. The Murray–Darling Basin is Australia’s most developed riverbasin (240 dams storing 29,893 GL) while the Lake Eyre Basin is one of the less devel-oped basins (1 dam storing 14 GL). We compared the long-term responses of water-bird communities in the two river basins at river basin, catchment and major wetlandscales. Waterbird abundances were strongly related to river flows and rainfall. For thedeveloped Murray–Darling Basin, we identified significant long-term declines in totalabundances, functional response groups (e.g., piscivores) and individual species ofwaterbird (n = 50), associated with reductions in cumulative annual flow. These trendsindicated ecosystem level changes. Contrastingly, we found no evidence of waterbirddeclines in the undeveloped Lake Eyre Basin. We also modelled the effects of the Aus-tralian Government buying up water rights and returning these to the riverine environ-ment, at a substantial cost (>3.1 AUD billion) which were projected to partly (18%improvement) restore waterbird abundances, but projected climate change effectscould reduce these benefits considerably to only a 1% or 4% improvement, withrespective annual recovery of environmental flows of 2,800 GL or 3,200 GL. Ourunique large temporal and spatial scale analyses demonstrated severe long-term eco-logical impact of water resource development on prominent freshwater animals, withimplications for global management of water resources.

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Dewhirst et al. 2017 An exploratory clustering approach for extracting stride parameters from tracking collars on free-ranging wild animals

Changes in stride frequency and length with speed are key parameters in animal locomotion research, and are commonly measured on a treadmill. We show that a clustering approach can be used to extract these variables from data collected by a tracking collar, which enables stride parameters to be measured during free-ranging locomotion in natural habitats.

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Callaghan et al. 2017 Assessing the reliability of avian biodiversity measures of urban greenspaces using eBird citizen science data

ABSTRACT. Urban greenspaces are important areas for biodiversity, serving multiple uses, sometimes including conservation and biodiversity management. Citizen science provides a cheap and potentially effective method of assisting biodiversity management in urban greenspaces. Despite this potential, the minimum amount of citizen science data required to adequately represent a community is largely untested. We used eBird data to test the minimum sampling effort required to be confident in results for three biological metrics, species richness, Shannon diversity, and community composition (Bray-Curtis similarity). For our data, from 30 urban greenspaces in North America, for a 90% threshold level, a minimum mean number of 210, 33, and 58 checklists were necessary for species richness, Shannon diversity, and community composition, respectively. However, when we eliminated those species that were present in fewer than 5% of checklists at a given site, there was a marked decrease in mean minimum number of checklists required (17, 9, and 52, respectively). Depending on the ecological questions of interest, eBird data may be a potentially reliable data source in urban greenspaces. We provide a validation methodology using eBird data, with its associated code in the R statistical environment, to provide confidence for land managers and community groups managing urban greenspaces.

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Centre for Ecosystem Science 2017 Submission to drafts of the Regulations for the Biodiversity Conservation Act, the amended Local Land Services Act and supporting tools in New South Wales

Executive Summary

The Centre for Ecosystem Science (CES), UNSW Australia, supports all legislative and other instruments of government that improve effectiveness of biodiversity conservation, founded on a strong evidence base. Current rates of loss of biodiversity around the world, in Australia and in New South Wales are unprecedented. The continued loss of biodiversity in NSW indicates a clear need to assess the effectiveness of the legislative framework that governs biodiversity conservation. CES welcomes the opportunity to provide a submission to the draft Regulations for the Biodiversity Conservation Act 2016 and Local Land Services Amendment Act 2016.

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Rees et al. 2017 In the absence of an apex predator, irruptive herbivores suppress grass seed production: Implications for small granivores


Many examples exist of species disappearing shortly after the extinction of a previously co-occurring apex predator, however processes connecting these events are often obscure. In Australian deserts, dingo Canis dingo eradication is associated with declines in abundances of small granivorous birds, even though dingoes and these flying birds rarely directly interact. We hypothesised that dingoes facilitate small granivores by reducing populations of large, grazing kangaroos Macropus spp., thereby increasing grass seed production and availability. To test this prediction, we monitored kangaroo abundances and surveyed grass seed production and biomass of native pastures in matched, desert habitats with dingoes and where dingoes were functionally extinct. Dingo absence was associated with 99.9% greater abundances of kangaroos, 88% - 98% lower pasture biomasses and 85% - 97% lower densities of grass seed heads. To test that these vegetation effects were related to kangaroo grazing, we constructed large herbivore exclosures in areas where dingoes where functionally extinct and there were no grazing livestock. After three years of kangaroo exclusion, pasture biomass and grass seed production were each 87% greater than in adjacent, grazed control plots. Regeneration of vegetation within the kangaroo exclosures demonstrated that kangaroo grazing was responsible for the differences in native pastures we had observed associated with the functional extinction of dingoes. Our results indicate that reduction of grass seed availability by kangaroo grazing is a likely explanation for the relative rarity of small granivorous birds in areas where dingoes are functionally extinct. In areas where apex predators have been eradicated, reintroducing and conserving apex predators or intensively controlling mammalian herbivores would be necessary to mitigate destructive herbivory.

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Jackson et al. 2017 The effect of relatedness and pack size on territory overlap in African wild dogs.

The degree of territorial overlap between neighbouring African wild dog (Lycaon pictus) packs varies greatly, yet the role of factors potentially affecting this remain unclear. We used movement data from 20 pack dyads to calculate the extent of territory overlap, finding that related neighbours had significantly greater levels of peripheral overlap and spent significantly more time in overlap zones than did unrelated packs. Pack size appeared to have little effect on overlap between related dyads, yet among unrelated neighbours larger packs tended to overlap more onto smaller packs’ territories. This spacing may affect the carrying capacity of protected areas, and have important management implications for intensively managed populations of this endangered species.

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Mills et al. 2017 Rewilded mammal assemblages reveal the missing ecological functions of granivores

Rewilding is a strategy for ecological restoration that uses reintroductions of animals to re-establish the ecological functions of keystone species. Globally, rewilding efforts have focused primarily on reinstating the ecological functions of charismatic megafauna. In Australia, rewilding efforts have focused on restoring the ecological functions of herbivorous and omnivorous rodents and marsupials weighing between 30-5000g inside of predator-proof exclosures.
In many arid ecosystems, mammals are considered the dominant seed predators. In Australian deserts, ants are considered to be the primary removers and predators of seeds and mammals unimportant removers and predators of seeds. However, most research on granivory in Australian deserts has occurred in areas where native mammals were functionally extinct.
Here, we compare rates of seed removal by mammals and ants on shrub seeds and abundance of shrub seedlings in two rewilded desert ecosystems (Arid Recovery Reserve and Scotia Wildlife Sanctuary) with adjacent areas possessing depauperate mammal faunas. We used foraging trays containing seeds of common native shrubs (Acacia ligulata and Dodonaea viscosa) to examine rates of seed removal by ants and mammals. We quantified the abundance of A. ligulata and D. viscosa seedlings inside and outside of rewilded areas along belt transects.
By excluding ants and mammals from foraging trays, we show that ants removed more seeds than mammals where mammal assemblages were depauperate, but mammals removed far more seeds than ants in rewilded areas. Shrub seedlings were more abundant in areas with depauperate mammal faunas than in rewilded areas.
Our study provides evidence that rewilding of desert mammal assemblages has restored the hitherto unappreciated ecological function of omnivorous rodents and bettongs as seed predators. We hypothesize that the loss of omnivorous mammals may be a factor that has facilitated shrub encroachment in arid Australia.
We contend that rewilding programs aimed at restoring ecological processes should not ignore consumers with relatively lower per capita consumptive effects. This is because consumers with low per capita consumptive effects often occur at high population densities or perform critical ecological functions and thus may have significant population level impacts that can be harnessed for ecological restoration.

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Jordan et al. 2017 Dynamics of direct inter-pack encounters in endangered African wild dogs

Aggressive encounters have important life history consequences, but little is known of their detailed dynamics, mainly due to the difficulties of directly observing encounters. We use high-resolution custom-built collars to describe detailed spatial dynamics of encounters between African wild dog packs. Surprisingly, our results indicate that encounters are lower risk than previously thought and do not appear to influence long-term ranging.

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Gordon et al. 2017 Shrub encroachment is linked to extirpation of an apex predator

Abstract The abundance of shrubs has increased throughout Earth's arid lands. This ‘shrub encroachment’ has been linked to livestock grazing, fire-suppression and elevated atmospheric CO2 concentrations facilitating shrub recruitment. Apex predators initiate trophic cascades which can influence the abundance of many species across multiple trophic levels within ecosystems. Extirpation of apex predators is linked inextricably to pastoralism, but has not been considered as a factor contributing to shrub encroachment. Here, we ask if trophic cascades triggered by the extirpation of Australia's largest terrestrial predator, the dingo (Canis dingo), could be a driver of shrub encroachment in the Strzelecki Desert, Australia. We use aerial photographs spanning a 51-year period to compare shrub cover between areas where dingoes are historically rare and common. We then quantify contemporary patterns of shrub, shrub seedling and mammal abundances, and use structural equation modelling to compare competing trophic cascade hypotheses to explain how dingoes could influence shrub recruitment. Finally, we track the fate of seedlings of an encroaching shrub, hopbush (Dodonaea viscosa angustissima), during a period optimal for seedling recruitment, and quantify removal rates of hopbush seeds by rodents from enriched seed patches. Shrub cover was 26–48% greater in areas where dingoes were rare than common. Our structural equation modelling supported the hypothesis that dingo removal facilitates shrub encroachment by triggering a four level trophic cascade. According to this model, increased mesopredator abundance in the absence of dingoes results in suppressed abundance of consumers of shrub seeds and seedlings, rodents and rabbits respectively. In turn, suppressed abundances of rodents and rabbits in the absence of dingoes relaxed a recruitment bottleneck for shrubs. The results of our SEM were supported by results showing that rates of hopbush seedling survival and seed removal were 1·7 times greater and 2·1 times lower in areas where dingoes were rare than common. Our study provides evidence linking the suppression of an apex predator to the historic encroachment of shrubs. We contend that trophic cascades induced by apex predator extirpation may be an overlooked driver of shrub encroachment.


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Kingsford 2017 The integrity of the water market in the Murray-Darling Basin View PDF
Torrents Ticó et al. 2017 On the right track? Comparing concurrent spoor and camera-traps surveys in Botswana

Spoor (track) counts and camera trapping are increasingly common survey tools used to detect the presence of species of interest in an area (occupancy). Given the significant time and financial investments in such surveys, and the management decisions based on their conclusions, it is imperative that confidence can be assigned to the results. We compared results collected simultaneously using spoor and camera-trap surveys at a human—wildlife interface in northern Botswana. While our spoor survey and camera-trap surveys detected a similar number of mammal species (17 and 15, respectively), the species detected by each method differed. Of the 21 species detected overall, only about half (52.4%) were detected by both methods, and these co-detected species had significantly higher occupancy estimates than those species detected by only one method. Moreover, the direct comparison showed that some tracks were missed or misidentified by the spoor survey. Our results suggest that over short time frames, neither method is ideal for detecting species at low densities, and that researchers should consider combining multiple methods in such circumstances.

Kingsford 2017 Submission on proposed Basin Plan amendments for the Northern Basin

Scientific evidence supports an increase in environmental flows to achieve sustainability for the environmental assets of the Northern Basin and the Murray-Darling Basin, beyond the 390GLs per year. The proposed reduction of 70 GL per year will continue to drive ongoing degradation of northern basin environmental values and ecosystem services provided by rivers, requiring future adjustments to provide more water for the rivers, particularly with the increasing effects of climate change of increasing temperatures and potential changes to run-off. This submission identifies eight major concerns which clearly show there is insufficient evidence for a recommendation to reduce the environmental flow target of the Northern Basin of the Murray-Darling Basin. The submission provides 10 reasons for supporting this position of rejecting the recommendations for reductions in water recovery.

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Callaghan et al. 2017 Travelling birds generate eco-travellers: The economic potential of vagrant birdwatching

Avitourism is one of the faster growing subsectors of ecotourism, recognized for its economic value. Much of our current understanding of the economic value of avitourism revolves around bird festivals, migration events, or well-known birdwatching sites. Birdwatchers are a diverse group, some of whom competitively seek vagrant birds (i.e., birds outside their normal geographic range). The economic value from these unpredictable and transient birdwatching events remains poorly known. Using the travel cost method in a readily-quantifiable environment, we estimated that a vagrant Black-backed Oriole in Pennsylvania, United States of America, stimulated travel activity valued at about $223,000 USD or about $3,000 per day over 67 days. Some birdwatchers value rare birds, contributing significant time and financial resources to their viewing. Identifying such significant real economic value from avitourism can help to evaluate competing costs in debate over human land-use scenarios.

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Walker et al. 2017 Sneeze to leave: African wild dogs (Lycaon pictus) use variable quorum thresholds mediated by sneezes in collective decisions

We demonstrated the importance of signals in collective decision-making and movement and showed for the first time that decisions to move-off were mediated by sneezes in African wild dogs; a first for any species. We showed that responses to these signals varied depending on dominant motivation, which illustrates how signals allow for negotiation (in effect, voting) that shapes decision-making in a wild, socially complex canid.

Purwandana et al. 2016 Ecological allometries and niche use dynamics across Komodo dragon ontogeny

Ontogenetic allometries in ecological habits and niche use are key responses by which individuals maximize lifetime fitness. Moreover, such allometries have significant implications for how individuals influence population and community dynamics. Here, we examined howbody size var- iation in Komodo dragons (Varanus komodoensis)influenced ecological allometries in their: (1) prey size preference, (2) daily movement rates, (3) home range area, and (4) subse- quent niche use across ontogeny. With increased body mass, Komodo dragons increased prey size with a dramatic switch from small (≤10 kg) to large prey (≥50 kg) in lizards heavier than 20 kg. Rates of foraging movement were described by a non-linear concave down response with lizard increasing hourly movement rates up until ∼20 kg body mass before decreasing daily movement suggesting reduced foraging ef- fort in larger lizards. In contrast, home range area exhibited a sigmoid response with increased body mass. Intrapopulation ecological niche use and overlap were also strongly structured by body size. Thus, ontogenetic allometries suggest Komodo dragon’s transition from a highly active foraging mode exploiting small prey through to a less active sit and wait feeding strategy focused on killing large ungulates. Further, our results suggest that as body size increases across ontogeny, the Komodo dragon exhibited marked ontogenetic niche shifts that enabled it to function as an entire vertebrate predator guild by by exploiting prey across multiple trophic levels.


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Parr et al 2016 Cranial Shape and the Modularity of Hybridization in Dingoes and Dogs; Hybridization Does Not Spell the End for Native Morphology

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Abrahms et al. 2016 Does wildlife resource selection accurately inform corridor conservation?

Identifying and protecting wildlife corridors are key conservation challenges. We reviewed connectivity studies employing resource selection analysis and present an empirical case study to test behaviour-specific predictions of connectivity. Our results, using African wild dogs as a case study, suggest that resource selection analyses that fail to consider an animal’s behavioural state are insufficient in targeting movement pathways and corridors for protection. This failure may result in misidentification of wildlife corridors and misallocation of limited conservation resources. Our findings underscore the need for considering patterns of animal movement in appropriate behavioural contexts to ensure the effective application of resource selection analyses for corridor planning

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Clarke-Wood et al. 2016 The ecological response of insectivorous bats to coastal lagoon degradation

Coastal lagoons provide key habitat for a wide range of biota but are often degraded by intense urbanization pressures. Insectivorous bats use these highly productive ecosystems and are likely to be impacted by their decline in quality. We compared bat activity and richness and invertebrate biomass and richness across a gradient of lagoon quality (9 lagoons) in the Greater Sydney region, Australia to determine the extent to which bats and their prey were impacted by lagoon degradation. Bats were more diverse and 19 times more active at higher quality lagoons. The trawling bat, Myotis macropus, was absent from all low quality lagoons, but these lagoons were used by other species such as Miniopterus schreibersii oceanensis. Invertebrate richness and biomass did not differ significantly across lagoon quality. We examined potential mechanisms of insectivorous bat decline at degraded lagoons by measuring toxic metal concentrations in bat fur, invertebrates and sediment. Lead and zinc were detected at environmentally significant levels in the sediments of lower quality lagoons. Furthermore, lead concentrations were 6 times the lowest observable adverse effects level for small mammals in the hair of one individual M. macropus. The present study demonstrates that coastal lagoons support a rich bat community, but ongoing development and pollution of these habitats is likely to negatively impact on insectivorous bat species, especially trawling species.


Jordan et al. 2016 Pair-specific scents in African wild dogs, Lycaon pictus, and an example of a potential method to identify signals within complex mixtures

Identifying the specific cues within complex signals is a key problem in animal communication research. We used a novel multivariate statistical approach to identify 19 candidate signals from almost 1000 candidate components within African wild dog urine. Testing the territorial function of these key chemicals is now feasible in the field, and is a critical stage in developing synthetic territorial signals for conservation management.

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Hubel et al. 2016 Energy cost and return for hunting in African wild dogs and cheetahs

African wild dogs are reported to hunt with energetically costly long chase distances. We recorded 1,119 high-speed chases of all members of a pack using custom-built collars, and showed that dogs ran multiple short, high-speed, mostly unsuccessful chases to capture prey. Modeling showed that the energy return of this approach substantially outweighs the cost of multiple short chases, suggesting that African wild dogs are more energetically robust than previously believed.

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Hubel et al. 2016 Additive opportunistic capture explains group hunting benefits in African wild dogs

This paper uses high-resolution GPS collar technology to challenge popular perceptions of African wild dogs collaborating to run down their prey over long-distances. African wild dogs actually owe their hunting success to short high-speed runs, undertaken during hunts that typically lack high-level coordination between dogs.

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Letnic et al. 2016 The crest-tailed mulgara (Dasycercus cristicauda) in the south-eastern Strzelecki Desert

Our survey trips always uncover something surprising. Recently we observed a range extension of the crest-tailed mulgara or ampurta, (Dasycercus cristicauda), which was very exciting! We discuss our observations in an article published in Australian Mammalogy. The article can be accessed here: 

The abstract of this article is reproduced below.

We report observations of the crest-tailed mulgara (Dasycercus cristicauda) in the south-eastern Strzelecki Desert. Our observations, made during spotlight surveys and using infrared cameras, extend the contemporary range of D. cristicauda to the east by 180 km but subfossil records show that these observations are within the pre-European-settlement range of the species. Whether our observations represent a range expansion or localised population irruption of a previously unknown refuge population is not known. Future studies are recommended to establish the distribution of D. cristicauda in the region and the factors determining its distribution and abundance

Rodríguez et al. 2015 A practical guide to the application of the IUCN Red List of Ecosystems criteria

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Baker et al 2015 A composite annual-resolution stalagmite record of North Atlantic climate over the last three millennia

Research on limestone formations in a remote Scottish cave has produced a unique 3000-year-long record of climatic variations that may have influenced historical events including the fall of the Roman Empire and the Viking Age of expansion. For full publication click here

Keith et al. 2015 The IUCN red list of ecosystems: Motivations, challenges and applications

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Murray et al. 2015 Tidal flats of the Yellow Sea: A review of ecosystem status and anthropogenic threats

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Skidmore et al. 2015 Environmental science: Agree on biodiversity metrics to track from space

Conservation scientists should collaborate more with space agencies, such as NASA and the European Space Agency (ESA), on identifying measures to help track biodiversity declines around the world. For full publication click here.


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