Diet of two fossorial herbivores in a seasonally snow-covered environment

2017 ◽  
Vol 39 (2) ◽  
pp. 169 ◽  
Author(s):  
K. Green ◽  
N. E. Davis ◽  
W. A. Robinson
Keyword(s):  
Range Expansion ◽  
Oryctolagus Cuniculus ◽  
Habitat Modification ◽  
Alpine Treeline ◽  
Winter Snow ◽  
Anthropogenic Habitat ◽  
Eastern Australia ◽  
European Rabbits ◽  
Elevational Range

To understand the recent elevational range expansion of European rabbits (Oryctolagus cuniculus) with declining snow cover and earlier snow thaw we examined their diet in relation to that of long-term residents, common wombats (Vombatus ursinus). The colonisation of eastern Australia by rabbits was effectively completed by 1910 when they reached an elevation of 1500 m (the winter snowline). Rabbits began to penetrate higher elevations only from the 1970s in association with anthropogenic habitat modification. Since 2011, rabbits have occupied elevations to the alpine treeline (~1850 m) throughout the year without the ameliorating presence of infrastructure or anthropogenically modified vegetation. Rabbits and wombats are both grazers preferring grasses (largely inaccessible beneath winter snow) and are spatially restricted in their foraging by their need to return to their burrows. Wombats used a much wider foraging range, enabling them to select preferred food. Rabbits, with a much smaller range, were constrained in their choice of forage mainly to plants that projected above the snow. Unexpectedly, rabbits fed intensively on leaves of eucalypts, food not typically consumed in substantial quantities by this species. These leaves, on stems regenerating after fire, will diminish in availability as stems mature, possibly halting the range expansion of rabbits.

scholarly journals Urbanization and Population Genetic Structure of the Panama City crayfish (Procambarus econfinae)

2019 ◽  
Vol 111 (2) ◽  
pp. 204-215
Author(s):  
Sarah I Duncan ◽  
Ellen P Robertson ◽  
Robert J Fletcher ◽  
James D Austin
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Habitat Loss ◽  
Legal Protection ◽  
Habitat Modification ◽  
Panama City ◽  
Habitat Patches ◽  
Anthropogenic Habitat ◽  
Habitat Loss And Fragmentation

Abstract For species with geographically restricted distributions, the impacts of habitat loss and fragmentation on long-term persistence may be particularly pronounced. We examined the genetic structure of Panama City crayfish (PCC), Procambarus econfinae, whose historical distribution is limited to an area approximately 145 km2, largely within the limits of Panama City and eastern Bay County, FL. Currently, PCC occupy approximately 28% of its historical range, with suitable habitat composed of fragmented patches in the highly urbanized western portion of the range and managed plantations in the more contiguous eastern portion of the range. We used 1640 anonymous single-nucleotide polymorphisms to evaluate the effects of anthropogenic habitat modification on the genetic diversity and population structure of 161 PCC sampled from across its known distribution. First, we examined urban habitat patches in the west compared with less-developed habitat patches in the east. Second, we used approximate Bayesian computation to model inferences on the demographic history of eastern and western populations. We found anthropogenic habitat modifications explain the genetic structure of PCC range-wide. Clustering analyses revealed significant genetic structure between and within eastern and western regions. Estimates of divergence between east and west were consistent with urban growth in the mid-20th century. PCC have low genetic diversity and high levels of inbreeding and relatedness, indicating populations are small and isolated. Our results suggest that PCC have been strongly affected by habitat loss and fragmentation and management strategies, including legal protection, translocations, or reintroductions, may be necessary to ensure long-term persistence.

scholarly journals Linking population size structure, heat stress and bleaching responses in a subtropical endemic coral

Coral Reefs ◽  
2021 ◽  
Author(s):  
Liam Lachs ◽  
Brigitte Sommer ◽  
James Cant ◽  
Jessica M. Hodge ◽  
Hamish A. Malcolm ◽  
...  
Keyword(s):  
Heat Stress ◽  
Size Structure ◽  
Temporal Trends ◽  
Early Recovery ◽  
Size Frequency Distribution ◽  
Frequency Distributions ◽  
Community Organisation ◽  
Size Frequency ◽  
Eastern Australia

AbstractAnthropocene coral reefs are faced with increasingly severe marine heatwaves and mass coral bleaching mortality events. The ensuing demographic changes to coral assemblages can have long-term impacts on reef community organisation. Thus, understanding the dynamics of subtropical scleractinian coral populations is essential to predict their recovery or extinction post-disturbance. Here we present a 10-yr demographic assessment of a subtropical endemic coral, Pocillopora aliciae (Schmidt-Roach et al. in Zootaxa 3626:576–582, 2013) from the Solitary Islands Marine Park, eastern Australia, paired with long-term temperature records. These coral populations are regularly affected by storms, undergo seasonal thermal variability, and are increasingly impacted by severe marine heatwaves. We examined the demographic processes governing the persistence of these populations using inference from size-frequency distributions based on log-transformed planar area measurements of 7196 coral colonies. Specifically, the size-frequency distribution mean, coefficient of variation, skewness, kurtosis, and coral density were applied to describe population dynamics. Generalised Linear Mixed Effects Models were used to determine temporal trends and test demographic responses to heat stress. Temporal variation in size-frequency distributions revealed various population processes, from recruitment pulses and cohort growth, to bleaching impacts and temperature dependencies. Sporadic recruitment pulses likely support population persistence, illustrated in 2010 by strong positively skewed size-frequency distributions and the highest density of juvenile corals measured during the study. Increasing mean colony size over the following 6 yr indicates further cohort growth of these recruits. Severe heat stress in 2016 resulted in mass bleaching mortality and a 51% decline in coral density. Moderate heat stress in the following years was associated with suppressed P. aliciae recruitment and a lack of early recovery, marked by an exponential decrease of juvenile density (i.e. recruitment) with increasing heat stress. Here, population reliance on sporadic recruitment and susceptibility to heat stress underpin the vulnerability of subtropical coral assemblages to climate change.

Long-term stress level in a small mammal species undergoing range expansion

Mammalia ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Adrien André ◽  
Johan Michaux ◽  
Jorge Gaitan ◽  
Virginie Millien
Keyword(s):  
Stress Level ◽  
Species Distribution ◽  
Small Mammal ◽  
Range Expansion ◽  
Mammal Species ◽  
Distribution Ranges ◽  
Northern Edge ◽  
Small Mammal Species ◽  
White Footed Mouse

Abstract Rapid climate change is currently altering species distribution ranges. Evaluating the long-term stress level in wild species undergoing range expansion may help better understanding how species cope with the changing environment. Here, we focused on the white-footed mouse (Peromyscus leucopus), a widespread small mammal species in North-America whose distribution range is rapidly shifting northward. We evaluated long-term stress level in several populations of P. leucopus in Quebec (Canada), from the northern edge of the species distribution to more core populations in Southern Quebec. We first tested the hypothesis that populations at the range margin are under higher stress than more established populations in the southern region of our study area. We then compared four measures of long-term stress level to evaluate the congruence between these commonly used methods. We did not detect any significant geographical trend in stress level across our study populations of P. leucopus. Most notably, we found no clear congruence between the four measures of stress level we used, and conclude that these four commonly used methods are not equivalent, thereby not comparable across studies.

scholarly journals Reassortment and persistence of influenza A viruses from diverse geographic origins within Australian wild birds: evidence from a small, isolated population of Ruddy turnstones

2021 ◽  
Author(s):  
Bethany J. Hoye ◽  
Celeste M. Donato ◽  
Simeon Lisovski ◽  
Yi-Mo Deng ◽  
Simone Warner ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Wild Birds ◽  
Influenza Viruses ◽  
Low Density ◽  
Isolated Population ◽  
Influenza A Viruses ◽  
Geographic Origins ◽  
Eastern Australia

Australian lineages of avian influenza A viruses (AIVs) are thought to be phylogenetically distinct from those circulating in Eurasia and the Americas, suggesting the circulation of endemic viruses seeded by occasional introductions from other regions. However, processes underlying the introduction, evolution and maintenance of AIVs in Australia remain poorly understood. Waders (Order Charadriiformes, Family Scolopacidae) may play a unique role in the ecology and evolution of AIVs, particularly in Australia, where ducks, geese and swans (Order Anseriformes, Family Anatidae) rarely undertake intercontinental migrations. Across a five-year surveillance period (2011–2015), Ruddy turnstones (Arenaria interpres) that ‘overwinter’ during the Austral summer in south eastern Australia showed generally low levels of AIV prevalence (0–2%). However, in March 2014 we detected AIVs in 32% (95% CI; 25–39%) of individuals in a small, low-density, island population 90km from the Australian mainland. This epizootic comprised three distinct AIV genotypes, each of which represent a unique reassortment of Australian, recently introduced Eurasian, and recently introduced American-lineage gene segments. Strikingly, the Australian-lineage gene segments showed high similarity to H10N7 viruses isolated in 2010 and 2012 from poultry outbreaks 900–1500km to the north. Together with the diverse geographic origins of the American and Eurasian gene segments, these findings suggest extensive circulation and reassortment of AIVs within Australian wild birds over vast geographic distances. Our findings indicate that long-term surveillance in waders may yield unique insights into AIV gene flow, especially in geographic regions like Oceania where Anatidae do not display regular inter- or intracontinental migration. IMPORTANCE High prevalence of avian influenza viruses (AIVs) was detected in a small, low-density, isolated population of Ruddy turnstones in Australia. Analysis of these viruses revealed relatively recent introductions of viral gene segments from both Eurasia and North America, as well as long-term persistence of introduced gene segments in Australian wild birds. These data demonstrate that the flow of viruses into Australia may be more common than initially thought and that, once introduced, these AIVs have the potential to be maintained within the continent. These findings add to a growing body of evidence suggesting Australian wild birds are unlikely to be ecologically-isolated from the highly pathogenic H5Nx viruses circulating among wild birds throughout the northern hemisphere.

Crop responses to lime in long-term pasture-crop rotations in a high rainfall area in south-eastern Australia

2001 ◽  
Vol 52 (3) ◽  
pp. 329 ◽  
Author(s):  
G. D. Li ◽  
K. R. Helyar ◽  
M. K. Conyers ◽  
B. R. Cullis ◽  
P. D. Cregan ◽  
...  
Keyword(s):  
Crop Production ◽  
Acid Soils ◽  
Crop Rotations ◽  
Severe Drought ◽  
High Rainfall ◽  
South Eastern ◽  
Permanent Pasture ◽  
Eastern Australia ◽  
South Eastern Australia

A long-term trial, known as ‘managing acid soils through efficient rotations’ (MASTER), commenced in 1992 to develop and demonstrate a cropping system that is economically viable on the highly acid soils of the traditional permanent pasture region in south-eastern Australia, so that their fertility is sustained or improved. There were 2 permanent pasture systems and 2 pasture–crop rotations, each with and without lime. This paper reports the effect of lime on crop production over the first cycle (6 years). On annual pasture–crop rotations, lime significantly increased the dry matter production at anthesis and grain yields of wheat (cv. Dollarbird) compared with the unlimed treatments. Averaged across years from 1992 to 1997 (excluding the severe drought year 1994), wheat crops produced 1.6 t/ha more grain on the limed treatments than on the unlimed treatments (3.6 v. 2.0 t/ha). On perennial pasture–crop rotations, the lime effects varied with crops grown at each phase and year. For example, despite being tolerant of acidity, oats (cv. Yarran) responded to lime in 1996. Likewise, triticale (cv. Abacus) responded to lime in 1997. Wheat (cv. Dollarbird) that is moderately tolerant to acidity responded to lime in phase 6 from 1992 to 1997 excluding 1994 (3.5 v. 1.7 t/ha). Acid-tolerant wheat varieties, triticale, and narrow-leaf lupins are considered the most viable crops for the soil and climatic conditions encountered in this high rainfall (5000—800 mm per annum) area of south-eastern Australia.

scholarly journals Spatial genetic analysis and long-term mark–recapture data demonstrate male-biased dispersal in a snake

2006 ◽  
Vol 3 (1) ◽  
pp. 33-35 ◽  
Author(s):  
J. Scott Keogh ◽  
Jonathan K Webb ◽  
Richard Shine
Keyword(s):  
Demographic Data ◽  
Molecular Data ◽  
Life History Trait ◽  
Eastern Australia ◽  
Powerful Approach ◽  
Adult Dispersal ◽  
Spatial Genetic Analysis ◽  
Polygynous Mating System ◽  
Important Life History Trait

Dispersal is an important life-history trait, but it is notoriously difficult to study. The most powerful approach is to attack the problem with multiple independent sources of data. We integrated information from a 14-year demographic study with molecular data from five polymorphic microsatellite loci to test the prediction of male-biased dispersal in a common elapid species from eastern Australia, the small-eyed snake Rhinoplocephalus nigrescens . These snakes have a polygynous mating system in which males fight for access to females. Our demographic data demonstrate that males move farther than females (about twice as far on average, and about three times for maximum distances). This sex bias in adult dispersal was evident also in the genetic data, which showed a strong and significant genetic signature of male-biased dispersal. Together, the genetic and demographic data suggest that gene flow is largely mediated by males in this species.

Stand dynamics and species composition control long-term post-fire trends in evapotranspiration and streamflow from South-eastern Australia’s Temperate Eucalyptus forests

2021 ◽  
Author(s):  
Assaf Inbar ◽  
Richard Benyon ◽  
Patrick Lane ◽  
Shyanika Lakmali ◽  
Shane Haydon ◽  
...  
Keyword(s):  
Species Composition ◽  
Forest Dynamics ◽  
Simulation Analysis ◽  
Stocking Density ◽  
Climatic Conditions ◽  
Water Yield ◽  
Multiple Sources ◽  
Acacia Dealbata ◽  
Eastern Australia

<p>Most of the water that ends up in Melbourne’s water supply catchments originates from wet Eucalyptus forests that are dominated by Eucalyptus regnans, the tallest known angiosperm on earth. Studies had shown that catchments that are dominated by these forests can experience a significant long-term (>100 years) reduction in streamflow after a stand-replacing fire, which was attributed to higher water-use of the dense overstory regrowth. However, despite several lines of evidence, the direction, extent and duration of post-fire hydrological behaviour vary significantly between catchments and between fire events. Here we propose that this variability is caused by initial stocking density and species composition after the fire, and the climatic conditions that prevail during forest regeneration that affect tree growth and mortality rates. In order to test the hypothesis, we formulated an ecohydrological model that simulates hydrology, growth and forest dynamics of E. regnans and Acacia dealbata, which are known to compete for resources during the initial stages of vegetation recovery. The new model shows high skill in predicting long-term streamflow when compared to observations using multiple sources of data. Simulation analysis shows that the direction, extent and duration of post-fire hydrological behaviour are sensitive to initial stocking density and to the relative abundance of species that regenerate after the fire, which influence the rate of self-thinning during stand development. Furthermore, simulation results show that the observed long-term reduction in streamflow is less likely to occur when the forest would have been less dense before the fire, which theoretically could only occur when a high proportion of the short-lived A. Dealbata regenerated after the previous fire. This highlights the importance of including mechanisms that control the effect of species composition on forest dynamics when modelling the effect of possible future climatic scenarios on water yield.</p>

Soil organic matter in rainfed cropping systems of the Australian cereal belt

Soil Research ◽  
2001 ◽  
Vol 39 (3) ◽  
pp. 435 ◽  
Author(s):  
R. C. Dalal ◽  
K. Y. Chan
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Management Practices ◽  
Performance Indicator ◽  
Annual Rainfall ◽  
Soil Productivity ◽  
Organic C ◽  
Soil C ◽  
Eastern Australia

The Australian cereal belt stretches as an arc from north-eastern Australia to south-western Australia (24˚S–40˚S and 125˚E–147˚E), with mean annual temperatures from 14˚C (temperate) to 26˚C (subtropical), and with annual rainfall ranging from 250 mm to 1500 mm. The predominant soil types of the cereal belt include Chromosols, Kandosols, Sodosols, and Vertosols, with significant areas of Ferrosols, Kurosols, Podosols, and Dermosols, covering approximately 20 Mha of arable cropping and 21 Mha of ley pastures. Cultivation and cropping has led to a substantial loss of soil organic matter (SOM) from the Australian cereal belt; the long-term SOM loss often exceeds 60% from the top 0–0.1 m depth after 50 years of cereal cropping. Loss of labile components of SOM such as sand-size or particulate SOM, microbial biomass, and mineralisable nitrogen has been even higher, thus resulting in greater loss in soil productivity than that assessed from the loss of total SOM alone. Since SOM is heterogeneous in nature, the significance and functions of its various components are ambiguous. It is essential that the relationship between levels of total SOM or its identif iable components and the most affected soil properties be established and then quantif ied before the concentrations or amounts of SOM and/or its components can be used as a performance indicator. There is also a need for experimentally verifiable soil organic C pools in modelling the dynamics and management of SOM. Furthermore, the interaction of environmental pollutants added to soil, soil microbial biodiversity, and SOM is poorly understood and therefore requires further study. Biophysically appropriate and cost-effective management practices for cereal cropping lands are required for restoring and maintaining organic matter for sustainable agriculture and restoration of degraded lands. The additional benefit of SOM restoration will be an increase in the long-term greenhouse C sink, which has the potentialto reduce greenhouse emissions by about 50 Mt CO2 equivalents/year over a 20-year period, although current improved agricultural practices can only sequester an estimated 23% of the potential soil C sink.

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