Elucidating dingo’s ecological roles: contributions from the Pelorus Island feral goat biocontrol project

2020 ◽  
Author(s):  
Benjamin L. Allen ◽  
Lee R. Allen ◽  
Michael Graham ◽  
Matt Buckman
Keyword(s):  
Native Vegetation ◽  
Apex Predators ◽  
Top Predators ◽  
Goat Population ◽  
Manipulative Experiments ◽  
Ecological Roles ◽  
Important Field ◽  
Small Livestock ◽  
Introduction Experiment ◽  
Feral Goat

ABSTRACT Understanding the ecological roles of apex predators remains an important field of study. The influence of apex predators on ecosystems can be either profound or negligible in different situations, and uncertainty still exists about the ecological roles of most top-predators, including Australian dingoes. This uncertainly is maintained by a dearth of experimental evidence investigating their roles. Such evidence is indispensable if dingo management is to be evidence-based. In this report, we discuss a recent experiment where dingoes were released on to an island as vertebrate biocontrol tools intended to eradicate feral goats and restore native vegetation being threatened by the goats. The experiment was successful, and the dingoes reduced the goat population to one or perhaps two male goats within ~2 years. This predator introduction experiment elucidated dingo’s effects on small livestock, their per capita predation rates, and their invasiveness or their ability to adapt and change their environment. The experiment confirmed that dingoes have the capacity to decimate populations of small livestock species and trigger a trophic cascade by reducing herbivory on vegetation. We encourage further manipulative experiments to explore the ubiquity of these results in different contexts.

scholarly journals Mesopredators change temporal activity in response to a recolonizing apex predator

2019 ◽  
Vol 30 (5) ◽  
pp. 1324-1335 ◽  
Author(s):  
Carolyn R Shores ◽  
Justin A Dellinger ◽  
Eric S Newkirk ◽  
Shannon M Kachel ◽  
Aaron J Wirsing
Keyword(s):  
Activity Patterns ◽  
Niche Overlap ◽  
Lynx Rufus ◽  
Gray Wolf ◽  
Apex Predator ◽  
Apex Predators ◽  
Anthropogenic Landscapes ◽  
Mediated Effects ◽  
Top Predators ◽  
Temporal Overlap

Abstract Apex predators can influence ecosystems through density and behaviorally mediated effects on herbivores and mesopredators. In many parts of the world, apex predators live in, or are returning to, landscapes that have been modified by people; so, it is important to understand their ecological role in anthropogenic landscapes. We used motion-activated game cameras to compare the activity patterns of humans and 2 mesopredators, coyotes (Canis latrans) and bobcats (Lynx rufus), in areas with and without an apex predator, the gray wolf (Canis lupus), in a multiuse landscape of the northwestern United States. In areas with wolves, there was a significant increase in temporal niche overlap between the mesopredators owing to higher levels of coyote activity at all time periods of the day. Temporal overlap between mesopredators and humans also increased significantly in the presence of wolves. Coyotes exposed to wolves increased their activity during dawn, day, and dusk hours. The increase in coyote activity was greatest during the day, when wolves were least active. The direction of change in bobcat activity in areas with wolves was opposite to coyotes, suggesting a behaviorally mediated cascade between wolves, coyotes, and bobcats, although these findings would need to be confirmed with further research. Our findings suggest that mesopredators in human-dominated systems may perceive humans as less dangerous than apex predators, that humans may be more likely to encounter mesopredators in areas occupied by top predators, and that behaviorally mediated effects of apex predators on mesopredators persist in human-dominated landscapes.

Conserving ecological roles of top predators in isolated mountains

2019 ◽  
Vol 30 (1) ◽  
Author(s):  
John F. Benson ◽  
Peter J. Mahoney ◽  
T. Winston Vickers ◽  
Jeff A. Sikich ◽  
Paul Beier ◽  
...  
Keyword(s):  
Top Predators ◽  
Ecological Roles

Distribution and Relative Abundance of Feral Goats in the Rangelands of Eastern Australia.

1993 ◽  
Vol 15 (2) ◽  
pp. 331 ◽  
Author(s):  
C Southwell ◽  
K Weaver ◽  
N Sheppard ◽  
P Morris
Keyword(s):  
Relative Abundance ◽  
New South ◽  
New South Wales ◽  
Aerial Survey ◽  
South Wales ◽  
Eastern Australia ◽  
Goat Population ◽  
Arid Rangelands ◽  
Feral Goat ◽  
Semi Arid

An aerial survey of 966,000 km2 of the arid/semi-arid rangelands of Queensland and New South Wales in the winter of 1992 indicated a minimum feral goat population of almost 1 million animals (density 0.97�0.12/km2). Observed density (f standard error) was higher in New South Wales (1.51�0.23/km2) than in Queensland (0.47�0.09/km2).

scholarly journals Switching from mesopredator to apex predator: how do responses vary in amphibians adapted to cave living?

2020 ◽  
Vol 74 (10) ◽  
Author(s):  
Raoul Manenti ◽  
Andrea Melotto ◽  
Olivier Guillaume ◽  
Gentile Francesco Ficetola ◽  
Enrico Lunghi
Keyword(s):  
Predator Recognition ◽  
Predatory Fish ◽  
Apex Predators ◽  
Fish Prey ◽  
Predator Cues ◽  
Top Predators ◽  
Novel Approach ◽  
Proteus Anguinus ◽  
History Of ◽  
Behavioural Experiments

Abstract The effective detection of both prey and predators is pivotal for the survival of mesopredators. However, the condition of being a mesopredator is strongly context dependent. Here we focus on two aquatic caudate species that have colonised caves: the Pyrenean newt (Calotriton asper) and the olm (Proteus anguinus). The former maintains both surface and subterranean populations, while only cave-adapted populations of the latter exist. Both species are apex predators in underground waterbodies, while the Pyrenean newt is a mesopredator in surface waterbodies. Shifting to a higher level of the trophic web through colonising caves may promote the loss of anti-predator response against surface apex predators, and an increase in the ability to detect prey. To test these two non-exclusive hypotheses, we integrated classical behavioural characterisations with a novel approach: the assessment of lateralisation (i.e. preference for one body side exposure). Behavioural experiments were performed using laboratory-reared individuals. We performed 684 trials on 39 Pyrenean newts and eight olms. Under darkness and light conditions, we tested how exposure to different chemical cues (predatory fish, prey and unknown scent) affected individuals’ activity and lateralisation. Both cave and surface Pyrenean newts responded to predator cues, while olms did not. In Pyrenean newts, predator cues reduced the time spent in movement and time spent in lateralisation associated with hunting. Our results show that predator recognition is maintained in a species where recently separated populations inhabit environments lacking of higher predators, while such behaviour tends to be lost in populations with longer history of adaptation. Significance statement Predator recognition can be maintained in animals adapted to predator free habitats, but varies with their history of adaptation. Species that are not at the apex of the food web can become top predators if they colonise subterranean environments. We compared the behavioural responses of the olm, a strictly cave species with a long underground evolutionary history, and of the Pyrenean newt, a facultative cave species that also has stream-dwelling populations. Moreover, we integrated a classical behavioural characterisation, such as movement detection, with a novel approach: the assessment of lateralisation. While olms do not respond to external predators scent, cave-dwelling newts still recognise it. This clearly indicates that predator recognition is still maintained in species that have colonised predator-free environments more recently.

scholarly journals Direct evidence of a prey depletion “halo” surrounding a pelagic predator colony

2021 ◽  
Vol 118 (28) ◽  
pp. e2101325118
Author(s):  
Sam B. Weber ◽  
Andrew J. Richardson ◽  
Judith Brown ◽  
Mark Bolton ◽  
Bethany L. Clark ◽  
...  
Keyword(s):  
Direct Evidence ◽  
Environmental Variability ◽  
Dispersion Model ◽  
Central Place ◽  
Natural World ◽  
Model Systems ◽  
Apex Predators ◽  
Top Predators ◽  
Global Positioning System Tracking ◽  
Prey Depletion

Colonially breeding birds and mammals form some of the largest gatherings of apex predators in the natural world and have provided model systems for studying mechanisms of population regulation in animals. According to one influential hypothesis, intense competition for food among large numbers of spatially constrained foragers should result in a zone of prey depletion surrounding such colonies, ultimately limiting their size. However, while indirect and theoretical support for this phenomenon, known as “Ashmole’s halo,” has steadily accumulated, direct evidence remains exceptionally scarce. Using a combination of vessel-based surveys and Global Positioning System tracking, we show that pelagic seabirds breeding at the tropical island that first inspired Ashmole’s hypothesis do indeed deplete their primary prey species (flying fish; Exocoetidae spp.) over a considerable area, with reduced prey density detectable >150 km from the colony. The observed prey gradient was mirrored by an opposing trend in seabird foraging effort, could not be explained by confounding environmental variability, and can be approximated using a mechanistic consumption–dispersion model, incorporating realistic rates of seabird predation and random prey dispersal. Our results provide a rare view of the resource footprint of a pelagic seabird colony and reveal how aggregations of these central-place foraging, marine top predators profoundly influence the oceans that surround them.

scholarly journals All the better to see you with: eyes and claws reveal the evolution of divergent ecological roles in giant pterygotid eurypterids

2015 ◽  
Vol 11 (8) ◽  
pp. 20150564 ◽  
Author(s):  
Victoria E. McCoy ◽  
James C. Lamsdell ◽  
Markus Poschmann ◽  
Ross P. Anderson ◽  
Derek E. G. Briggs
Keyword(s):  
Visual System ◽  
Sister Taxon ◽  
Characteristic Morphology ◽  
Visual Systems ◽  
Top Predators ◽  
Representative Species ◽  
Ecological Roles ◽  
High Level ◽  
Predatory Arthropods

Pterygotid eurypterids have traditionally been interpreted as active, high-level, visual predators; however, recent studies of the visual system and cheliceral morphology of the pterygotid Acutiramus contradict this interpretation. Here, we report similar analyses of the pterygotids Erettopterus, Jaekelopterus and Pterygotus , and the pterygotid sister taxon Slimonia . Representative species of all these genera have more acute vision than A. cummingsi . The visual systems of Jaekelopterus rhenaniae and Pterygotus anglicus are comparable to that of modern predatory arthropods. All species of Jaekelopterus and Pterygotus have robust crushing chelicerae, morphologically distinct from the weaker slicing chelicerae of Acutiramus . Vision in Erettopterus osiliensis and Slimonia acuminata is more acute than in Acutiramus cummingsi , but not to the same degree as in modern active predators, and the morphology of the chelicerae in these genera suggests a grasping function. The pterygotids evolved with a shift in ecology from generalized feeder to specialized predator. Pterygotid eurypterids share a characteristic morphology but, although some were top predators, their ecology differs radically between genera.

scholarly journals The Tankwa Karoo National Park feral goat population: A unique genetic resource

2014 ◽  
Vol 44 (1) ◽  
pp. 43 ◽  
Author(s):  
A Kotzé ◽  
JP Grobler ◽  
E Van Marle-Köster ◽  
T Jonker ◽  
DL Dalton
Keyword(s):  
National Park ◽  
Genetic Resource ◽  
Goat Population ◽  
Feral Goat

scholarly journals Resource partitioning among top predators in a Miocene food web

2013 ◽  
Vol 280 (1750) ◽  
pp. 20122138 ◽  
Author(s):  
M. Soledad Domingo ◽  
Laura Domingo ◽  
Catherine Badgley ◽  
Oscar Sanisidro ◽  
Jorge Morales
Keyword(s):  
Resource Partitioning ◽  
Prey Capture ◽  
Tooth Enamel ◽  
Isotope Analysis ◽  
The Other ◽  
Tree Cover ◽  
Apex Predators ◽  
Top Predators ◽  
Body Sizes ◽  
Open Woodland

The exceptional fossil sites of Cerro de los Batallones (Madrid Basin, Spain) contain abundant remains of Late Miocene mammals. From these fossil assemblages, we have inferred diet, resource partitioning and habitat of three sympatric carnivorous mammals based on stable isotopes. The carnivorans include three apex predators: two sabre-toothed cats (Felidae) and a bear dog (Amphicyonidae). Herbivore and carnivore carbon isotope ( δ 13 C) values from tooth enamel imply the presence of a woodland ecosystem dominated by C 3 plants. δ 13 C values and mixing-model analyses suggest that the two sabre-toothed cats, one the size of a leopard and the other the size of a tiger, consumed herbivores with similar δ 13 C values from a more wooded portion of the ecosystem. The two sabre-toothed cats probably hunted prey of different body sizes, and the smaller species could have used tree cover to avoid encounters with the larger felid. For the bear dog, δ 13 C values are higher and differ significantly from those of the sabre-toothed cats, suggesting a diet that includes prey from more open woodland. Coexistence of the sabre-toothed cats and the bear dog was likely facilitated by prey capture in different portions of the habitat. This study demonstrates the utility of stable isotope analysis for investigating the behaviour and ecology of members of past carnivoran guilds.

Small Group Research in Europe

2002 ◽  
Vol 7 (4) ◽  
pp. 265-274 ◽  
Author(s):  
Francisco Gil Rodríguez ◽  
Carlos María Alcover de la Hera
Keyword(s):  
Social Psychology ◽  
Work Teams ◽  
Rapid Development ◽  
Spanish History ◽  
Organizational Contexts ◽  
Scarce Resources ◽  
Long Period ◽  
Group Research ◽  
Important Field ◽  
Scientific Results

After a long period of scarce resources and a long delay in new scientific results suffered as a consequence of recent Spanish history, research concerning groups has experienced a rapid development over the last 15 years of the 20th century—the result of the late but then clear institutionalization of psychology into university structure. Although most research has been carried out at the very heart of social psychology and along the traditional lines of the field, a significant growth in the study of groups and work teams in organizational contexts can now be highlighted, coinciding with the tendency detected internationally during the last years. Beyond the normalization of group research in Spain, it is necessary to point out its excessive dependency in both theory and methodology on models and tools elaborated throughout North America and Europe. The present review closes with the proposal of creating a European formative curriculum for group psychologists in order to unify and promote research within this active and important field of psychology.

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