Potential competition between two top-order predators following a dramatic contraction in the diversity of their prey base

2011 ◽  
Vol 61 (1) ◽  
pp. 29-47 ◽  
Author(s):  
Raylene Cooke ◽  
Rohan Bilney ◽  
John White
Keyword(s):  
Habitat Management ◽  
Mammalian Species ◽  
Dietary Overlap ◽  
Study Region ◽  
Terrestrial Mammals ◽  
Potential Competition ◽  
European Settlement ◽  
Eastern Australia ◽  
Significant Divergence ◽  
Potential Resource

AbstractTwo sympatric native top-order predators, the sooty owl (Tyto tenebricosa tenebricosa) and powerful owl (Ninox strenua) coexist throughout much of their range in south-eastern Australia. Following European settlement, however, major changes in resource availability for these predators potentially resulted in increased competition, especially for food. This study examined ecological attributes of both species, including intersexual differences in the sooty owl, potential resource partitioning and whether competition may be occurring. Dietary overlap was high between female sooty owls and powerful owls (0.90), compared to overlap between male sooty owls and powerful owls (0.67), with three mammalian species contributing over 74% of their diets. Sooty and powerful owls coexisted throughout the study region, regularly roosting within the same vegetation types, and in similar locations, although microhabitat differences were apparent. Sooty owls displayed aseasonal breeding, although a peak in fledging in spring coincided with powerful owl breeding. Both species exclusively nested in similar size mountain grey gums (Eucalyptus cypellocarpa), however, hollow characteristics differed slightly. Significant divergence along a single niche dimension was not detected between powerful and sooty owls, as they had similar diets, habitat usage and activity times, potentially resulting in competition. Reproductive output was low for both species, however, the degree to which competitive interactions influenced this remains unknown. To minimise potential competition, longterm feral predator control and improved habitat management is recommended to increase the density and diversity of small terrestrial mammals, as this should result in diversification of the sooty owl diet, reducing dietary overlap with powerful owls.

Prevalence of threatened native species in canid scats from coastal and near-coastal landscapes in south-eastern Australia

2010 ◽  
Vol 32 (2) ◽  
pp. 117 ◽  
Author(s):  
Andrew W. Claridge ◽  
Douglas J. Mills ◽  
Simon C. Barry
Keyword(s):  
Native Species ◽  
Mammal Species ◽  
Study Region ◽  
Terrestrial Mammals ◽  
South Eastern ◽  
Eastern Australia ◽  
Coastal Landscapes ◽  
Wild Dog ◽  
Wild Dogs ◽  
Prey Items

Predator scat analysis was used to infer the potential impact of wild dogs (Canis lupus dingo, C. l. familiaris and hybrids of the two) on threatened native terrestrial mammals in coastal and near-coastal southern New South Wales, Australia. Prey items recorded in wild dog scats were compared with those occurring in scats of the red fox collected at the same study sites. Six threatened mammal species were recorded in either wild dog or fox scats: eastern pygmy possum, grey-headed flying fox, long-nosed potoroo, southern brown bandicoot, white-footed dunnart and yellow-bellied glider. The prevalence of these threatened species in fox scats was significantly higher than in wild dog scats. Otherwise, wild dogs mostly consumed larger prey items such as swamp wallabies and wombats whereas foxes more heavily preyed on small mammals such as antechinus and rats. Our results suggest that foxes are the major threat to threatened mammal species in the study region. Land management agencies in south-eastern mainland Australia should therefore focus on controlling foxes for biodiversity gain.

scholarly journals Relative abundance and activity patterns of terrestrial mammals in Pacuare Nature Reserve, Costa Rica

2017 ◽  
Vol 9 (1) ◽  
pp. 15-21
Author(s):  
Stephanny Arroyo-Arce ◽  
Ian Thomson ◽  
Carlos Fernandez ◽  
Roberto Salom-Perez
Keyword(s):  
Costa Rica ◽  
Nature Reserve ◽  
Mammalian Species ◽  
Activity Patterns ◽  
Abundant Species ◽  
Camera Trap ◽  
Central American ◽  
Leopardus Pardalis ◽  
Terrestrial Mammals ◽  
History Of

Located in Costa Rica, Pacuare Nature Reserve has a long established history of wildlife monitoring programs primarily focused on species of nesting marine turtles and the Agami herons (Agamia agami) found within the reserve. Our research represents the first as­sessment on the local terrestrial mammal populations. Data was col­lected by using seven camera trap stations distributed within the boundaries of the reserve. From April 2015 to March 2016, and after a total of 1 643 camera trap nights, we were able to identify 11 terres­trial mammalian species distributed in six orders and nine families. The most abundant species was the common opossum (Didelphis marsu­pialis), followed by the ocelot (Leopardus pardalis). A noticeably ab­sent species, otherwise common throughout the area, was the Central American agouti (Dasyprocta punctata). Our results are similar to those from other protected areas in the Northeastern Caribbean coast of Costa Rica.

Comparative mitochondrial phylogeography of two legless lizards (Pygopodidae) from Queensland’s fragmented woodlands

2020 ◽  
Vol 66 (3-4) ◽  
pp. 142-150
Author(s):  
Jessica Worthington Wilmer ◽  
Andrew P. Amey ◽  
Carmel McDougall ◽  
Melanie Venz ◽  
Stephen Peck ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Evolutionary History ◽  
The West ◽  
European Settlement ◽  
Low Genetic Diversity ◽  
Eastern Australia ◽  
Wide Range ◽  
History Of ◽  
Open Forests ◽  
Fossorial Species

Sclerophyll woodlands and open forests once covered vast areas of eastern Australia, but have been greatly fragmented and reduced in extent since European settlement. The biogeographic and evolutionary history of the biota of eastern Australia’s woodlands also remains poorly known, especially when compared to rainforests to the east, or the arid biome to the west. Here we present an analysis of patterns of mitochondrial genetic diversity in two species of Pygopodid geckos with distributions centred on the Brigalow Belt Bioregion of eastern Queensland. One moderately large and semi-arboreal species, Paradelma orientalis, shows low genetic diversity and no clear geographic structuring across its wide range. In contrast a small and semi-fossorial species, Delma torquata, consists of two moderately divergent clades, one from the ranges and upland of coastal areas of south-east Queensland, and other centred in upland areas further inland. These data point to varying histories of geneflow and refugial persistance in eastern Australia’s vast but now fragmented open woodlands. The Carnarvon Ranges of central Queensland are also highlighted as a zone of persistence for cool and/or wet-adapted taxa, however the evolutionary history and divergence of most outlying populations in these mountains remains unstudied.

scholarly journals Predictive Ecosystem Mapping of South-Eastern Australian Temperate Forests Using Lidar-Derived Structural Profiles and Species Distribution Models

2019 ◽  
Vol 11 (1) ◽  
pp. 93 ◽  
Author(s):  
Melissa Fedrigo ◽  
Stephen B. Stewart ◽  
Stephen H. Roxburgh ◽  
Sabine Kasel ◽  
Lauren T. Bennett ◽  
...  
Keyword(s):  
Species Distribution ◽  
Vegetation Structure ◽  
Species Distribution Models ◽  
Sustainable Forest Management ◽  
Continuous Distribution ◽  
Forest Monitoring ◽  
Distribution Models ◽  
Study Region ◽  
South Eastern ◽  
Eastern Australia

Modern approaches to predictive ecosystem mapping (PEM) have not thoroughly explored the use of ‘characteristic’ gradients, which describe vegetation structure (e.g., light detection and ranging (lidar)-derived structural profiles). In this study, we apply a PEM approach by classifying the dominant stand types within the Central Highlands region of south-eastern Australia using both lidar and species distribution models (SDMs). Similarity percentages analysis (SIMPER) was applied to comprehensive floristic surveys to identify five species which best separated stand types. The predicted distributions of these species, modelled using random forests with environmental (i.e., climate, topography) and optical characteristic gradients (Landsat-derived seasonal fractional cover), provided an ecological basis for refining stand type classifications based only on lidar-derived structural profiles. The resulting PEM model represents the first continuous distribution map of stand types across the study region that delineates ecotone stands, which are seral communities comprised of species typical of both rainforest and eucalypt forests. The spatial variability of vegetation structure incorporated into the PEM model suggests that many stand types are not as continuous in cover as represented by current ecological vegetation class distributions that describe the region. Improved PEM models can facilitate sustainable forest management, enhanced forest monitoring, and informed decision making at landscape scales.

scholarly journals A mitochondrial genetic divergence proxy predicts the reproductive compatibility of mammalian hybrids

2020 ◽  
Vol 287 (1928) ◽  
pp. 20200690 ◽  
Author(s):  
Richard Allen ◽  
Hannah Ryan ◽  
Brian W. Davis ◽  
Charlotte King ◽  
Laurent Frantz ◽  
...  
Keyword(s):  
Genetic Distance ◽  
Predictive Power ◽  
Mammalian Species ◽  
Haldane’S Rule ◽  
Terrestrial Mammals ◽  
Hybrid Offspring ◽  
Haldane's Rule ◽  
Species Pairs ◽  
Small Overlap ◽  
Relative Fertility

Numerous pairs of evolutionarily divergent mammalian species have been shown to produce hybrid offspring. In some cases, F 1 hybrids are able to produce F 2 s through matings with F 1 s. In other instances, the hybrids are only able to produce offspring themselves through backcrosses with a parent species owing to unisexual sterility (Haldane's Rule). Here, we explicitly tested whether genetic distance, computed from mitochondrial and nuclear genes, can be used as a proxy to predict the relative fertility of the hybrid offspring resulting from matings between species of terrestrial mammals. We assessed the proxy's predictive power using a well-characterized felid hybrid system, and applied it to modern and ancient hominins. Our results revealed a small overlap in mitochondrial genetic distance values that distinguish species pairs whose calculated distances fall within two categories: those whose hybrid offspring follow Haldane's Rule, and those whose hybrid F 1 offspring can produce F 2 s. The strong correlation between genetic distance and hybrid fertility demonstrated here suggests that this proxy can be employed to predict whether the hybrid offspring of two mammalian species will follow Haldane's Rule.

scholarly journals Change in the diet of sooty owls (Tyto tenebricosa) since European settlement: from terrestrial to arboreal prey and increased overlap with powerful owls

2006 ◽  
Vol 33 (1) ◽  
pp. 17 ◽  
Author(s):  
Rohan J. Bilney ◽  
Raylene Cooke ◽  
John White
Keyword(s):  
Monitoring System ◽  
Vulpes Vulpes ◽  
Control Strategies ◽  
Large Array ◽  
Dietary Overlap ◽  
Mammal Species ◽  
Critical Weight ◽  
Terrestrial Mammal ◽  
European Settlement ◽  
Fox Control

The current diet of the sooty owl (Tyto tenebricosa) was determined by analysing freshly regurgitated pellets collected beneath their roosting sites in East Gippsland, Victoria. Comparisons were then made with: (i) prehistoric and historic diet from bone deposits found in cave roosts, and (ii) diet of a sympatric owl species, the powerful owl (Ninox strenua). Sooty owls consumed a large array of terrestrial mammal species before European settlement, but only three terrestrial species were detected in their current diet, a reduction of at least eight species since European settlement. To compensate, sooty owls have increased their consumption of arboreal prey from 55% to 81% of their diet. Arboreal species are also a major component of the powerful owl diet and this prey shift by sooty owls has increased dietary overlap between these two species. Predation by foxes (Vulpes vulpes) and other feral species is likely to have reduced the amount of terrestrial prey available to sooty owls since European settlement. Investigation of changes in the diet of sooty owls may offer a unique monitoring system for evaluating the ability of fox-control strategies to influence increases in numbers of critical-weight-range mammals.

scholarly journals Reversed sexual dimorphism and altered prey base: the effect on sooty owl (Tyto tenebricosa tenebricosa) diet

2011 ◽  
Vol 59 (5) ◽  
pp. 302 ◽  
Author(s):  
Rohan J. Bilney ◽  
John G. White ◽  
Raylene Cooke
Keyword(s):  
Sexual Dimorphism ◽  
Small Mammals ◽  
Prey Availability ◽  
Mammalian Species ◽  
Control Programs ◽  
European Settlement ◽  
Mammal Conservation ◽  
Reversed Sexual Dimorphism ◽  
Conservation Concern ◽  
And Function

The ecology and function of many Australian predators has likely been disrupted following major changes in prey base due to declines in distribution and abundance of small mammals following European settlement. This study investigated various aspects of the dietary ecology of sooty owls (Tyto tenebricosa tenebricosa), including sexual variation as they potentially exhibit the greatest degree of reversed sexual dimorphism of any owl species worldwide. Sooty owls are highly opportunistic predators of non-volant small mammals, consuming most species known to exist in the region, so their diet fluctuates seasonally and spatially due to varying prey availability, and is particularly influenced by the breeding cycles of prey. Significant intersexual dietary differences existed with female sooty owls predominantly consuming much larger prey items than males, with dietary overlap at 0.62. The current reliance on relatively few native mammalian species is of conservation concern, especially when mammal declines are unlikely to have ceased as many threatening processes still persist in the landscape. Sooty owl conservation appears inextricably linked with small mammal conservation. Conservation efforts should be focussed towards improving prey densities and prey habitat, primarily by implementing control programs for feral predators and preventing the loss of hollow-bearing trees throughout the landscape.

scholarly journals Camera-trapping survey to assess diversity, distribution and photographic capture rate of terrestrial mammals in the aftermath of the ethnopolitical conflict in Manas National Park, Assam, India

2018 ◽  
Vol 10 (8) ◽  
pp. 12008 ◽  
Author(s):  
Dipankar Lahkar ◽  
M. Firoz Ahmed ◽  
Ramie H. Begum ◽  
Sunit Kumar Das ◽  
Bibhuti Prasad Lahkar ◽  
...  
Keyword(s):  
National Park ◽  
Mammalian Species ◽  
Capture Rate ◽  
Political Conflict ◽  
Camera Trapping ◽  
Terrestrial Mammals ◽  
Independent Events ◽  
Key Species ◽  
Almost All ◽  
Capture Rates

 Information on the presence and distribution of species is crucial for conservation planning and management within a region.  Documentation of species assemblages in Manas National Park (MNP) in the aftermath of conflict is critical for informed conservation interventions.  For nearly two decades (1990–2010), conservation efforts in MNP were compromised by ethno−political conflict.  We conducted camera trapping surveys of terrestrial mammals across three administrative forest ranges (Panbari, Bansbari and Bhuyanpara) of MNP in 2017.  A systematic survey with 118 trap locations accumulated data over 6,173 trap-days.  We obtained 21,926 photographs of mammals belonging to 13 families and 25 species, of which 13 are threatened.  We calculated photographic capture rate index (PCRI) using independent events.  Trap specific PCRI’s were used to map the spatial variation in capture rates.  We observed variation in capture rate between Bansbari-Bhuyanpara where conflict ended in 2003 and has remained peaceful, and Panbari, a forest range where conflict ended later in 2016.  Our results further indicate lower capture rates of mammalian prey species and small felids, but higher capture rates of four large carnivores in Panbari as opposed to Bansbari-Bhuyanpara.  These results highlighted the fact that despite a history of ethno-political conflict in the region, although almost all mammalian species expected to occur in the park were detected and confirmed, present evidence indicated ethno-political conflict influences the distribution of several key species.  In depth studies assessing mammalian prey densities, distribution and density are required to further understand the effects of conflict. 

scholarly journals The challenge of setting ‘climate ready’ ecological targets for environmental flow planning

2021 ◽  
Author(s):  
Meegan Judd ◽  
Nicholas Bond ◽  
Avril Horne
Keyword(s):  
Water Availability ◽  
Climate Adaptation ◽  
Environmental Flows ◽  
Large River ◽  
Study Region ◽  
Run Off ◽  
Eastern Australia ◽  
Management Plans ◽  
Ecological Objectives ◽  
Adaptation Options

Implementing environmental flows has emerged as a major restoration tool for addressing the impacts of hydrologic alteration in large river systems. The ‘natural flow paradigm’ has been a central guiding principle for determining important ecohydrological relationships. Yet, climate change and associated changes in rainfall run off relationships, seasonality of flows, disruptions to food webs and species life cycle cues mean these existing relationships will, in many circumstances, become obsolete. Revised thinking around setting ecological objectives is required to ensure restoration targets are achievable, particularly in regions where water scarcity is predicted to increase. Through this lens ‘climate ready’ targets are those that are robust to changing water availability or incorporate future adaptation options. Future objective setting should be based around the inclusion of changing climate and water availability, and the associated species and ecosystem vulnerabilities, and expected outcomes under different policy and adaptation options. This paper uses south eastern Australia as a case study region to review the extent to which current water management plans include climate considerations and adaptation in objective setting. Results show untested climate adaptation inclusions, and a general lack of acknowledgement of changing hydrological and ecological conditions in existing management plans. In response this paper presents a process for setting objectives so they can be considered ‘climate ready’.

scholarly journals Montane mire vegetation of the New England Tablelands Bioregion of Eastern Australia

2020 ◽  
Vol 1 ◽  
pp. 37-51 ◽  
Author(s):  
John T. Hunter ◽  
Vanessa H. Hunter
Keyword(s):  
Multidimensional Scaling ◽  
New England ◽  
Profile Analysis ◽  
Classification Systems ◽  
Current Conservation ◽  
Study Region ◽  
Mire Vegetation ◽  
Threat Status ◽  
Metric Multidimensional Scaling ◽  
Eastern Australia

Aims: To use unsupervised techniques to produce a hierarchical classification of montane mires of the study region. Study area: New England Tablelands Bioregion (NETB) of eastern Australia. Methods: A dataset of 280 vascular floristic survey plots placed across the variation in montane mires of the NETB was collated. Vegetation types were identified with the aid of a clustering method based on group averaging and tested using similarity profile analysis (SIMPROF) and through ordinations using Bray-Curtis similarity and non-metric multidimensional scaling (NMDS). A hierarchical schema was developed based on EcoVeg hierarchy and was circumscribed using positive and negative diagnostic taxa via similarity percentage analysis (SIMPER) and importance based on summed cover scores and frequency. Results: We defined one macrogroup to include all montane mire vegetation of the NETB and within these two groups and twelve alliances. Conclusions: Our study re-enforced the separation of bogs from other montane mire systems and confirmed the separation of fens and wet meadows, a distinction that previously had not been independently tested. Based on our results many existing montane mire communities of the NETB have been ill-defined at multiple hierarchical levels, leading to confusion in threat status and mapping. Additionally, nearly half of the alliances we recognise were found to have no correlates within current classification systems, which necessarily has implications for the effectiveness of current conservation planning. Taxonomic reference: PlantNET (http://plantnet.rbgsyd.nsw.gov.au/, accessed June 2016). Abbreviations: BC Act = Biodiversity Conservation Act; EPBC Act = Environmental Protection and Biodiversity Act; NETB = New England Tablelands Bioregion; NMDS = non-metric multidimensional scaling; PCT = plant community type; RE = regional ecosystem; SIMPER = similarity percentage analysis; SIMPROF = similarity profile analysis.

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