Population ecology of the nectar-feeding squirrel glider (Petaurus norfolcensis) in remnant forest in subtropical Australia

2010 ◽  
Vol 37 (2) ◽  
pp. 77 ◽  
Author(s):  
David J. Sharpe ◽  
Ross L. Goldingay
Keyword(s):  
Population Density ◽  
Population Ecology ◽  
Food Resource ◽  
First Year ◽  
Nectar Feeding ◽  
Remnant Habitat ◽  
Squirrel Glider ◽  
Remnant Forest ◽  
Nectar Availability ◽  
Natality Rate

Context. Nectar is a temporally variable food resource. However, because few studies describe the population dynamics of nectar-feeding non-flying mammals, it is unclear how such populations are influenced by resource availability. Aims. We investigated the population ecology of the squirrel glider (Petaurus norfolcensis) in remnant forest in Brisbane, Australia, where nectar was a dominant food item. Methods. We used 36 tree-mounted traps to census a squirrel glider population inhabiting a 47-ha urban remnant over a 4-year period. Key results. A total of 201 gliders was captured 705 times in 3729 trap-nights (19% trap success). Population density peaked in the first year at ~1.6 individuals ha–1, and declined down to ~0.5 individuals ha–1 by the final year. This change in population density appeared to be mediated by annual variation in flowering intensity. Births occurred from March to November, peaking between April and July. All females >1 year old bred in each year of the study, with a mean litter size of 1.7 (n = 122). The overall natality rate was 1.9, indicating that females occasionally bred twice per year. The sex ratio was at parity in the pouch and in the trappable population. Gliders first entered the trappable population at 4 months of age, and persisted for a mean of 32 months. The maximum longevity was at least 6 years. Conclusions. The demographic characteristics of this squirrel glider population within remnant forest surrounded by urban development were similar to those reported elsewhere. Variation in nectar availability appears to have a substantial influence on the dynamics of squirrel glider populations. Implications. The substantial variation in population size driven by food availability raises concerns regarding the viability of small populations of nectarivorous non-flying mammals inhabiting remnant habitat.

Population ecology of the squirrel glider (Petaurus norfolcensis) and the sugar glider (P. breviceps) (Maruspialia : Petauridae) at Limeburners Creek, on the central north coast of New South Wales

1995 ◽  
Vol 22 (4) ◽  
pp. 471 ◽  
Author(s):  
DG Quin
Keyword(s):  
Population Ecology ◽  
New South ◽  
New South Wales ◽  
Food Resource ◽  
North Coast ◽  
Juvenile Dispersal ◽  
South Wales ◽  
Sugar Glider ◽  
Timing Of Births ◽  
Squirrel Glider

The population ecology of the squirrel glider (Petaurus norfolcensis) and the sugar glider (P. breviceps) was studied at Limeburners Creek Nature Reserve, on the central north coast of New South Wales. The study was undertaken between July 1986 and November 1988. Sugar and squirrel gliders at Limeburners Creek exhibited similar home-range sizes (2.54 ha) despite considerable differences in mean mass between the species (squirrel glider 192-213 g; sugar glider, 104-119 g). Squirrel gliders existed at higher densities (049-1.54 ha-') than did sugar gliders (0.24454 ha-') and populations of both species exhibited male-biased sex ratios. The timing of births was not consistent between years and, at least in the squirrel glider, occurred in almost all months of the year over the 2.5-year study. Usually a winter peak in births that extended into spring was apparent, sometimes following an autumn peak. Mean litter size for both species (1.8-1.9) was similar to that recorded for the sugar glider in Victoria. Most adult females of both species exhibited the capacity to raise two litters in a year. Hence, natality rates (2.3-2.4 young per year) at Limeburners Creek were high relative to those recorded for the sugar glider in Victoria. Recruit persistence time (3.0-3.5 seasons) was similar between the species and recruitment appeared to be most successful during years when heavy eucalypt and Banksia flowering was recorded. Populations of both species were characterised by high rates of juvenile dispersal and mortality. Young gliders dispersed at a mean age of 10.9 and 12.5 months in the sugar glider and the squirrel glider, respecti~e1y;SquirreI gliders nested in colonies of 2-Bindividuals. Usually at least one male and two females nested together, suggesting a polygynous mating strategy. The mating system of the sugar glider at Limebumers Creek was less clear, but colonies appeared to comprise at least monogamous pairs with or without a surplus of males. Sugar glider colonies at Limebumers Creek varied in size from two to seven individuals. The larger squirrel gliders were clearly dominant to the smaller sugar gliders in interspecific behavioural interactions. Inconsistencies in body-weight fluctuations between years for both species were thought to be a consequence of the unpredictable nature of the aseasonal, coastal climates and resulting food resource abundances.

scholarly journals POPULATION ECOLOGY OF THE NORTHERN SLIMY SALAMANDER (PLETHODON GLUTINOSUS) IN EAST-CENTRAL ILLINOIS

2015 ◽  
pp. 17-21
Author(s):  
John A. Crawford ◽  
Andrew R. Kuhns ◽  
Mathys J. Meyer
Keyword(s):  
Population Density ◽  
Population Ecology ◽  
Demographic Data ◽  
Ecosystem Integrity ◽  
East Central ◽  
Plethodon Glutinosus ◽  
Capture Success ◽  
Plethodontid Salamanders ◽  
Management Plans ◽  
Central Illinois

The importance of plethodontid salamanders in forested habitats has been recognized for decades and more recently plethodontids have been touted as a model taxon for monitoring ecosystem integrity and recovery. However, basic demographic data that are crucial to conservation and management plans are currently lacking for many species and regions. The objectives of our study were to characterize the population density, biomass, and capture success of a peripheral population of Plethodon glutinosus to provide a comparison for eastern populations and set a baseline for future monitoring of Midwestern populations. We estimated the population density of P. glutinosus at our site to be 0.41 salamanders/m2, with an estimated biomass of 0.70 g/m2. We did not find any evidence for temperature or precipitation affecting capture success. Our results showed that our density estimate falls within the range of other population ecology studies of Plethodon and sets a baseline for other peripheral Midwestern populations.

Demographic parameters of the squirrel glider (Petaurus norfolcensis) in an urban forest remnant

2017 ◽  
Vol 65 (3) ◽  
pp. 141
Author(s):  
David J. Sharpe ◽  
Ross L. Goldingay
Keyword(s):  
Urban Forest ◽  
Local Population ◽  
Adult Survival ◽  
First Year ◽  
Detailed Knowledge ◽  
Apparent Survival ◽  
Key Population ◽  
Forest Remnant ◽  
Squirrel Glider ◽  
Urban Matrix

The effective management of species requires detailed knowledge of key population parameters. A capture–mark–recapture study of the squirrel glider (Petaurus norfolcensis) was conducted in an urban forest remnant in Brisbane, south-east Queensland. A total of 187 adult gliders (96 females, 91 males) was captured 620 times, in 19 sessions over a 4-year period. A Cormack–Jolly–Seber model was employed to estimate adult survival and abundance. Factors that may affect survival (e.g. sex, year, season) were included in population models. The overall probability of annual apparent survival was 0.49 ± 0.08. The capture probability over the duration of the study was 0.38 ± 0.03. The size of the local population was highest in the first year of the study (70–113 individuals) but then declined and generally remained low in the last two years. Apparent survival may include an unknown component of dispersal. However, our study area was mostly surrounded by a hostile urban matrix, so the effect of dispersal may have been minimal. Further studies that assess the survival of squirrel gliders are needed to assess the extent to which this parameter varies among localities.

Effects of food, kinship, and density on the longevity of spiderlings

2021 ◽  
pp. 741-751
Author(s):  
Marta Luciane Fischer ◽  
Lays Cherobim Parolin ◽  
Felipe Marcel Neves ◽  
German Antonio Villanueva-Bonilla ◽  
João Vasconellos-Neto
Keyword(s):  
Population Density ◽  
Laboratory Experiments ◽  
Survival Rates ◽  
Food Resource ◽  
Behavioral Characteristic ◽  
Risk Of Predation ◽  
Large Populations ◽  
Main Factors ◽  
Conspecific Tolerance ◽  
Loxosceles Laeta

Cannibalism is a behavioral characteristic found in a wide variety of animal groups. Although the rates of cannibalism can vary from one group to another, studies indicate that the main factors contributing to an increase in the frequency of such behavior are the availability of food, population density, the behavior and availability of victims, and environmental stress. We carried out different laboratory experiments to assess whether different factors such as the presence or absence of food among siblings and non-siblings, and at different densities among conspecific and heterospecific individuals, affect longevity of recently emerged Brazilian brown recluse (Loxosceles intermedia Mello-Leitão, 1934) and Chilean recluse (Loxosceles laeta (Nicolet, 1849)) spiderlings during periods of starvation. The results revealed that the survivorship of L. laeta during starvation was significantly higher than that of L. intermedia and that the addition of conspecific individuals increased survival rates by 1.5- and 1.6-fold, respectively. The tolerance of conspecifics differed between the two species, and generally, cannibalism was not observed, probably due to the risk of predation and limited consumption by weakened spiders, which coincided with the continued availability of endogenous vitelline reserves, thus indicating that the use of these spiderlings as a food resource may act to regulate starvation in more resistant spiders. The greater longevity and conspecific tolerance of L. laeta may be important factors contributing to the establishment of large populations of this spider in restricted areas, whereas for L. intermedia, hunger probably functions as a trigger for dispersal.

POPULATION CHANGE IN AN OUTBREAK OF THE DOUGLAS-FIR TUSSOCK MOTH, ORGYIA PSEUDOTSUGATA (LEPIDOPTERA: LYMANTRIIDAE), IN CENTRAL ARIZONA

1974 ◽  
Vol 106 (11) ◽  
pp. 1171-1174 ◽  
Author(s):  
Richard R. Mason
Keyword(s):  
Population Density ◽  
Population Change ◽  
Larval Density ◽  
Douglas Fir ◽  
First Year ◽  
Tussock Moth ◽  
The Third ◽  
Orgyia Pseudotsugata ◽  
Early Instar ◽  
Central Arizona

AbstractChanges in population density were evaluated over an outbreak cycle of the Douglas-fir tussock moth. Growth rate of populations was independent of larval density in the first year, but thereafter became a reciprocal function of density, terminated by complete population collapse at the end of the third year. Through correlation analyses, it was found that density of small larvae accounted for a large proportion of the change in population density between years. This suggests that the local infestations developed largely from resident populations of at least 2 years and not from spread of early instar larvae during the outbreak.

The population ecology of the squirrel glider (Petaurus norfolcensis) within a network of remnant linear habitats

2002 ◽  
Vol 29 (4) ◽  
pp. 329 ◽  
Author(s):  
Rodney van der Ree
Keyword(s):  
Agricultural Landscape ◽  
South Eastern ◽  
Linear Habitats ◽  
Continuous Forest ◽  
Eastern Australia ◽  
Squirrel Glider ◽  
Density Population ◽  
Natality Rate ◽  
South Eastern Australia

The geographic range of the squirrel glider (Petaurus norfolcensis) in south-eastern Australia largely corresponds with fertile soils highly suited for agriculture. As a consequence of extensive clearing for agriculture, the conservation of P. norfolcensis in south-eastern Australia is now reliant on a mosaic of many fragmented and isolated patches of woodland and forest. In this study, I investigated the population dynamics of P. norfolcensis in an agricultural landscape where most remnant woodland occurs as linear strips along roadsides, unused road reserves and watercourses. A total of 251 gliders were trapped 1343 times within the linear habitats between December 1996 and November 1998. Gliders were resident within the linear strips at 0.95–1.54 individuals ha–1, a density equal to, or greater than, that recorded elsewhere for the species in continuous forest. All adult females were reproductively active and the mean natality rate was 1.9 young per adult female per year. Overall, the population age-structure appeared to be stable. While currently supporting a stable, high-density population, the long-term viability of these remnants as habitat is not assured because roadside reserves are narrow, easily fragmented and subjected to a host of deleterious processes causing ongoing habitat loss and degradation.

Space use by female agile antechinus: are teat number and home-range size linked?

2016 ◽  
Vol 43 (4) ◽  
pp. 348 ◽  
Author(s):  
Juliey Beckman ◽  
Alan Lill
Keyword(s):  
Population Density ◽  
Home Range ◽  
Food Resource ◽  
Food Abundance ◽  
Energetic Cost ◽  
Home Ranges ◽  
Female Population ◽  
Eastern Australia ◽  
Minimal Convex ◽  
Teat Number

Context The number of teats that a female agile antechinus (Antechinus agilis) possesses effectively determines her initial litter size. In the Otway Ranges, south-eastern Australia, numerous separate populations in which all females have either six or 10 teats occur fairly close together in similar, contiguous forest at comparable altitudes and latitudes. Six-teat and 10-teat females have a similar mean mass, but the latter have a 1.7 × greater reproductive potential and so should have a greater nutritional requirement while raising young than do six-teat females. Theoretically, they could meet this requirement by occupying larger and/or more exclusive home ranges during breeding than do six-teat females do (provided that their food-resource abundance is comparable), albeit at a greater energetic cost. Aims The aim of the study was to determine whether 10-teat A. agilis females occupied larger and less overlapping home ranges than did six-teat females. To interpret the findings more meaningfully, it was necessary to compare food abundance and habitat characteristics in areas occupied by the two phenotypes. Methods The investigation was conducted in six-teat and 10-teat A. agilis areas in cool temperate forest over 22 months. Population density was determined by mark–recapture methods and arthropod prey biomass and abundance by pitfall trapping. Vegetation structure and plant-taxa abundance and diversity were determined by standard plant-survey methods. Female home-range estimates determined by radio-tracking were based on 95% minimal convex polygons (MCP) and kernel analysis. Home-range overlap was based on 80% MCP range determinations and core areas were calculated from utilisation plots. Key results Female population density was 2.5 × lower in exclusively 10-teat than in exclusively six-teat populations. Radio-tracked 10-teat females’ home ranges less commonly overlapped those of identified female neighbours and, on average, were 1.5 × larger than ranges of six-teat females. Food abundance and composition was similar in six-teat and 10-teat areas, but ground cover was denser and more complex in the latter areas. Conclusions Food-resource availability was similar in the six-teat and 10-teat phenotype areas, so the larger, and probably more exclusive, home ranges of 10-teat females could reflect greater nutritional requirements resulting from having larger litters, and account for their lower population density. Implications The A. agilis teat-number variation pattern in the Otways may be a rare, visible example of ongoing incipient speciation. This makes it of great scientific and conservation value and it is important to document how the phenomenon operates.

Population density ofDiabrotica virgifera virgiferaLeConte beetles in Serbian first year and continuous maize fields

2009 ◽  
Vol 133 (6) ◽  
pp. 430-437 ◽  
Author(s):  
I. Sivcev ◽  
S. Stankovic ◽  
M. Kostic ◽  
N. Lakic ◽  
Z. Popovic
Keyword(s):  
Population Density ◽  
First Year ◽  
Continuous Maize

scholarly journals Biological and ecological aspects of Bathygobius soporator (Valenciennes, 1837) (Perciformes, Gobiidae) from Santa Catarina, Southern Brazil

2021 ◽  
Vol 61 ◽  
pp. e20216115
Author(s):  
Germano Henrique Costa Barrilli ◽  
Julia Gomes do Vale ◽  
Gabriela Stahelin ◽  
Joaquim Olinto Branco
Keyword(s):  
Sexual Dimorphism ◽  
Trophic Ecology ◽  
Food Resource ◽  
First Year ◽  
Southern Brazil ◽  
Santa Catarina ◽  
Main Food ◽  
Ecological Aspects ◽  
Fast Development ◽  
First Year Of Life

Bathygobius soporator (popularly known as "Maria da toca") is a species that, although abundant, is little studied in aspects regarding growth, feeding and reproduction in southern Brazil. Studies on trophic ecology still raise questions on the species’ actual diet, especially in the context of algae participating as a food resource or an accidental intake. Thus, this study aims to fill this gap, evaluating the growth, feeding, and reproduction of this species. Monthly samples from two periods (1997-1998 and 2005-2006) were analyzed for growth, feeding, and reproduction parameters, totalizing 1177 individuals evaluated. Our results demonstrate that Bathygobius soporator is a species of fast development, reaching the age of first maturation before the first year of life. It presents a sexual dimorphism, being males larger than females. Reproductive peaks occur in the spring and summer months. The species presented a broad trophic spectrum, including algae as the main food resource, not just an accidental intake. The omnivorous-opportunistic trophic ecology of this species is emphasized, agreeing with the information of previous studies.

scholarly journals Non-linear relationship between food resource exploitation and population density of stored-product pests

2000 ◽  
Vol 18 (No. 3) ◽  
pp. 81-85 ◽  
Author(s):  
V. Stejskal
Keyword(s):  
Population Density ◽  
Food Resource ◽  
Food Products ◽  
Population History ◽  
Resource Exploitation ◽  
Pest Population ◽  
Critical Thresholds ◽  
Pest Infestation ◽  
Stored Product Pests ◽  
Food Commodities

  The main current strategies (IPM, HACCP) to control pests in stored food products are based on critical thresholds derived from pest population density. These thresholds usually do not consider cumulative effects of earlier pest infestation although injuries caused by biotic pest organisms to stored food commodities are irreversible. We present conceptual and illustrative models showing that population size indices, in contrast to cumulative (population history) indices, could (i) underestimate critical thresholds if pest population can grow exponentially and (ii) provide incorrect information about the level of stored food damage if pest population density can fluctuate. The importance of entomological food microanalysis and continual “cumulative monitoring” based on trapping is discussed with respect to HACCP and IPM programmes in stored food products.

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