Population dynamics of three species of dasyurid marsupials in arid central Australia: a 10-year study

2001 ◽  
Vol 28 (5) ◽  
pp. 493 ◽  
Author(s):  
Christopher R. Dickman ◽  
Adele S. Haythornthwaite ◽  
Gayle H. McNaught ◽  
Paul S. Mahon ◽  
Bobby Tamayo ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Life Histories ◽  
Arid Zone ◽  
Early Spring ◽  
Early Summer ◽  
Late Winter ◽  
Sand Ridge ◽  
Red Foxes ◽  
Central Australia ◽  
Simpson Desert

This study investigated the population dynamics of three species of dasyurid marsupials in sand ridge habitat of the Simpson Desert, western Queensland, over a 10-year period between March 1990 and December 1999. The lesser hairy-footed dunnart (Sminthopsis youngsoni), was captured most consistently over the period of study, followed by the wongai ningaui (Ningaui ridei), and the mulgara (Dasycercus cristicauda). Rates of recapture were low (4.5–22.2%), probably because individuals of each species are very mobile. All species bred in late winter or early spring when animals were aged at least 8–10 months, and independent juveniles first appeared usually in summer. S. youngsoni reared a second litter in late spring or early summer in 3 of the 10 years studied, when the availability of food was likely to have been high; neither N. ridei nor D. cristicauda were known to attempt a second litter within a season. To explore factors that might influence population dynamics, we compared capture rates of each species with measures of rainfall, temperature, vegetation cover, abundance of predators [feral cats (Felis catus), red foxes (Vulpes vulpes), and goannas (Varanus spp.)], dragons, other dasyurids and indices of food abundance. The abundance of S. youngsoni appeared to depend primarily on the cover of spinifex 7–9 months earlier, that of D. cristicauda was related most strongly to rainfall 7–9 months earlier, while that of N. ridei was related to minimum temperature lagged by 1–3 months. While the dynamics of other arid-zone mammals are driven demonstrably by interactions between rainfall, resource availability and predation, our findings suggest that dasyurids have limited flexibility in their life histories and are influenced more subtly and by factors such as facilitation that are just beginning to become apparent.

Life cycle, population dynamics and productivity of Ventrosia maritima in the Evros Delta (northern Aegean Sea)

2005 ◽  
Vol 85 (2) ◽  
pp. 375-382 ◽  
Author(s):  
Theodoros Kevrekidis ◽  
Thomas Wilke
Keyword(s):  
Population Dynamics ◽  
Life Cycle ◽  
Outer Part ◽  
Dry Weight ◽  
Early Summer ◽  
Late Winter ◽  
Published Data ◽  
Annual Life Cycle ◽  
Frequency Method ◽  
Innermost Part

Life cycle, population dynamics and productivity of the larviparous mudsnail species Ventrosia maritima were investigated at low salinities (0·3–6 psu) in differentiated parts of a Mediterranean lagoon (Monolimni Lagoon). Monthly samples were collected during the period from February 1998 to February 1999 in both parts of the lagoon. Ventrosia maritima displayed an annual life cycle. Recruitment occurred in summer and autumn at the outer part of the lagoon and additionally in late winter at the innermost part. A positive correlation was found between the percentages of small individuals and salinity or sediment organic matter at the outer part. Growth practically ceased in winter. The mudsnail displayed remarkable densities and an increase in growth in spring at <1 psu indicating that it is highly tolerant to extremely low salinities. Population density showed a significant seasonal variation; it increased from early summer to autumn (30,000–40,000 individuals m−2) following the summer and autumn recruitment. No significant correlation between the density of V. maritima and several examined physicochemical variables was found; a negative correlation was observed between the density of the mudsnail and that of the co-occurring polychaete Streblospio shrubsolii. Secondary production calculated by the size–frequency method gave a mean annual density (N) of 9740 ind m−2, a mean biomass (B) of 1·66 g ash-free dry weight (AFDW) m−2 y−1, a production (P) of 4·51 g m−2 y−1 and a P:B ratio of 2·72 at the outer part of the lagoon and a N of 14,570 ind m−2, a B of 3·2 g AFDW m−2 y−1, a P of 9·9 g m−2 y−1 and a P:B ratio of 3·09 at the innermost part. At the innermost part of the lagoon, where the seawater renewal rate and hydro-dynamism were lower and the sediment finer and organically richer, V. maritima displayed more recruitment pulses, a larger body size and a denser and more productive population than the one at the outer part. Our findings are compared to published data for the direct-developing congeners V. ventrosa and V. truncata.

Biology and population dynamics of the black-flanked rock-wallaby (Petrogale lateralis lateralis) in the central wheatbelt of Western Australia

2011 ◽  
Vol 33 (2) ◽  
pp. 117 ◽  
Author(s):  
Nicole Willers ◽  
Peter Mawson ◽  
Keith Morris ◽  
Roberta Bencini
Keyword(s):  
Population Dynamics ◽  
Body Condition ◽  
Resource Competition ◽  
Condition Index ◽  
Early Summer ◽  
The Body ◽  
Conservation Strategies ◽  
Late Winter ◽  
Body Condition Index ◽  
Males And Females

Through a mark–recapture study, we explored aspects of the biology and population dynamics in the largest known population of the black-flanked rock-wallaby (Petrogale lateralis lateralis) at Mt Caroline Nature Reserve, in the Western Australian wheatbelt in 2007–10. The body condition index of males and females varied significantly over time but fluctuated similarly for both sexes. Males and females followed a pattern of best condition in early summer, declining through autumn and reaching their poorest condition in early spring. Body condition was closely related to rainfall in the period ~3–6 months before trapping sessions. Births occurred throughout the year with two reproductive peaks, in autumn and late winter/spring. Reproductive rates averaged over 90% annually, except in 2007 when they averaged 76%. Significantly fewer females bred during 2007, and those females were in poorer body condition. Females with a higher body condition index were more likely to reproduce (P = 0.003) but body condition did not influence the sex of offspring. The sex ratio of offspring did not differ significantly from parity and did not support either the Trivers–Willard or local resource competition hypotheses. This information should help to predict population trends and develop appropriate conservation strategies for this threatened species.

Seasonal dynamics of Proteocephalus sagittus in the stone loach Barbatula barbatula from the Haná River, Czech Republic

2004 ◽  
Vol 78 (3) ◽  
pp. 225-229 ◽  
Author(s):  
J. Jarkovský ◽  
B. Koubková ◽  
T. Scholz ◽  
M. Prokeš ◽  
V. Baruš
Keyword(s):  
Czech Republic ◽  
Seasonal Cycle ◽  
Early Spring ◽  
Early Summer ◽  
Fish Host ◽  
Late Winter ◽  
Stone Loach ◽  
Barbatula Barbatula ◽  
Infection Parameters ◽  
First Time

AbstractThe seasonal cycle of the cestode Proteocephalus sagittus (Cestoda: Proteocephalidae) was studied for the first time in the stone loach Barbatula barbatula from the Haná River, Czech Republic. A total of 180 loaches were examined monthly from January to December 2001. The parasite occurred in loaches throughout the year but infection parameters differed significantly among seasons, with the highest values of prevalence and abundance from the late winter to the early summer. Parasite recruitment took place in the winter and early spring and the worms sexually matured in the late spring and early summer. In contrast to P. torulosus, the gravid worms of which laid eggs only at the end of the spring/beginning of the summer, gravid worms of P. sagittus were also found, although in low numbers, in the autumn and early winter. The rate of infection of loach with P. sagittus was neither dependent on the sex nor on the size of its fish host.

Ability to recover overrides the negative effects of flooding on growth of tropical grasses Chloris gayana and Panicum coloratum

2015 ◽  
Vol 66 (1) ◽  
pp. 100 ◽  
Author(s):  
José A. Imaz ◽  
Daniel O. Giménez ◽  
Agustín A. Grimoldi ◽  
Gustavo G. Striker
Keyword(s):  
Recovery Period ◽  
Growth Period ◽  
Early Spring ◽  
Early Summer ◽  
Late Winter ◽  
Negative Effects ◽  
Tropical Grasses ◽  
Panicum Coloratum ◽  
Flooding Event ◽  
Chloris Gayana

This study assessed the flooding tolerance of the tropical grasses Chloris gayana Kunth and Panicum coloratum L. at different times of the year: (i) late winter flooding for 50 days (WF), (ii) early spring flooding (SF) for 20 days, and (iii) long-term flooding covering both periods (WF + SF, 70 days). A growth period under well-watered conditions was allowed after each flooding event to assess recovery of plant species. Plants were harvested after each flooding event and at the end of the recovery period. Panicum coloratum had higher tolerance to WF than C. gayana. Treatment WF did not affect biomass in P. coloratum, whereas it reduced biomass of flooded plants by 38% in C. gayana. Treatment SF did not differentiate the species for tolerance; both registered moderate reduction in their growth (20–30%). Under WF + SF, C. gayana showed additional reduction in its growth over that observed when subjected separately to either WF or SF, whereas P. coloratum did not. Both species displayed remarkably fast recovery from flooding when temperatures rose during early summer, attaining biomass equivalent to that of non-flooded plants 1 month after water subsided. Therefore, although P. coloratum appears slightly more tolerant during flooding than C. gayana, both species are promising for introduction in temperate lowland grasslands.

Habitat use, population dynamics and species identification of mulgara, Dasycercus blythi and D. cristicauda, in a zone of sympatry in central Australia

2011 ◽  
Vol 59 (3) ◽  
pp. 156 ◽  
Author(s):  
Chris R. Pavey ◽  
Catherine E. M. Nano ◽  
Steven J. B. Cooper ◽  
Jeff R. Cole ◽  
Peter J. McDonald
Keyword(s):  
Population Dynamics ◽  
Habitat Use ◽  
Species Identification ◽  
Capture Rate ◽  
Habitat Types ◽  
Red Foxes ◽  
Sympatric Populations ◽  
Size Dimorphism ◽  
Sand Plain ◽  
Central Australia

Dasycercus cristicauda and Dasycercus blythi are significant mesopredators in arid Australia and both species are threatened nationally. We investigated size dimorphism, habitat use, and population dynamics of sympatric populations during a low rainfall period in central Australia and examined congruence between morphological and molecular methods of species identification. Our molecular analyses confirmed the presence of two Dasycercus species in sympatry and showed that the descriptions of Woolley (2005) allowed confident identification of the two species in the field. We captured 23 D. cristicauda and 55 D. blythi over 39 months on 20 monitoring plots and another 49 survey sites stratified across five habitat types within a 7000 km2 area. Both species showed sexual dimorphism in body mass with males being significantly heavier. The species typically occupied non-overlapping habitat; D. cristicauda was restricted to sandridges (n = 4 sites) with an understorey dominated by spinifex (Triodia), whereas D. blythi occupied sand plain and gibber plain, the latter being a new habitat for the species. Capture rate of D. cristicauda peaked in autumn-winter 2008 and winter 2009. D. blythi exhibited similar variability with peaks in winter 2009 and summer-autumn 2010. We consider that the relatively low abundance of each species during low rainfall periods makes them vulnerable to predation by feral house cats and European red foxes.

Late winter – early spring sedimentation off the Great Whale River, southeastern Hudson Bay

1988 ◽  
Vol 25 (6) ◽  
pp. 930-933 ◽  
Author(s):  
B. d'Anglejan ◽  
G. Biksham
Keyword(s):  
Algal Biomass ◽  
Sediment Traps ◽  
Early Spring ◽  
Early Summer ◽  
Late Winter ◽  
Hudson Bay ◽  
Sedimentation Rates ◽  
Summer Period ◽  
The Mean ◽  
Peak Runoff

Sediment traps were used to measure particle-settling fluxes in serial moorings offshore of Great Whale River (Hudson Bay), both under the late winter sea-ice cover and during and after breakup. Before breakup, the settling fluxes ranged between 0.25 and 2 g cm−2 100 a−1, increasing from April to May in response to the progressively larger under-ice algal biomass. Fluxes also increased with depth. During and after breakup, including the early summer period of peak runoff, sedimentation rates increased to values of up to 33 g cm−2100 a−1. These fluxes agree with the mean sedimentation rate determined from 210Pb activities in the underlying sediments.

Sea ice conditions during an early spring voyage in the eastern Weddell Sea, Antarctica

Polar Record ◽  
1988 ◽  
Vol 24 (148) ◽  
pp. 49-54 ◽  
Author(s):  
H. Eicken ◽  
T. C. Grenfell ◽  
B. Stonehouse
Keyword(s):  
Open Water ◽  
Early Spring ◽  
Early Summer ◽  
Weddell Sea ◽  
Late Winter ◽  
Main Body ◽  
Pack Ice ◽  
Large Populations ◽  
Differential Expansion ◽  
Ice Pack

AbstractDuring a late winter and early spring oceanographic voyage south into the Weddell Sea the icebreaker RV Polarstern first encountered patches and bands of loose floes in 58°S; these increased over the next 150 km to form closed ice pack which extended 1000 km to the coast. Along the coast the ship encountered almost continuous shore leads and polynyas that formed repeatedly despite persistently low air and sea temperatures. These areas of open water, which are generally visible in USA NOAA and USSR METEOR satellite photographs, form under the action of strong offshore winds that carry the main body of pack ice west and southwest. Grease ice, pancake ice and nilas spreading over the open water are rafted and ridged by windgenerated stresses to double thickness or more; these kinds of ice were continually driven westward, accumulating in a distinctive zone along the eastern edge of the pack ice. Polynyas and leads narrow and disappear temporarily only when winds with northerly or westerly components bring the pack ice toward the land, and reform as soon as offshore winds predominate. Open water, often more than 15 km wide, was present close to the ship throught the spring voyage, facilitating oceanographic work as far south as 77°S. Polarstern's full icebreaking capacity was needed only occasionally when winds temporarily pressed the pack ice against the coast. The presence throughout early spring of both fast and pack ice, separated by a zone of thin ice or open water, is essential to large populations of Weddell seals, emperor penguins and whales in the area. The transect from the continent included ice pack that was undergoing early summer decay, characterized by differential expansion and melting which brought about a gradual decrease in concentration toward the ice edge.

Long distance movements and the use of fire mosaics by small mammals in the Simpson Desert, central Australia..

2001 ◽  
Vol 23 (2) ◽  
pp. 125 ◽  
Author(s):  
M Letnic
Keyword(s):  
Small Mammals ◽  
Arid Zone ◽  
Radio Telemetry ◽  
Movement Patterns ◽  
Long Distance ◽  
Habitat Mosaics ◽  
Central Australia ◽  
Single Night ◽  
Simpson Desert

Using recapture data and radio-telemetry, the movement patterns of small mammals occupying burned and unburned habitats in the Simpson Desert, western Queensland were investigated. Long-term, between trap sessions, recapture rates of small mammals ranged from 7.3 % for Sminthopsis youngsoni to less than 1 % for Pseudomys desertor. Seventeen individuals including Pseudomys hermannsburgensis, S. youngsoni and Notomys alexis were observed to make longdistance movements (> 500 m). The longest recorded movement in this study was 5.7 km by a male S. youngsoni. Telemetry and recapture data indicate that individual P. hermannsburgensis, S. youngsoni and N. alexis can move more than 700 m and up to 2 km in a single night. Radiotracked P. hermannsburgensis and N. alexis utilised a mosaic of burned and unburned habitats in a single night of foraging. Low rates of recapture for small mammals in the Australian arid zone suggest that the populations of many species consist largely of transient individuals. Some species of small mammals appear to have sufficient mobility to locate resource rich patches and utilise habitat mosaics along a continuum of scales. These range from long-distance and presumably unidirectional migrations of 10 km or more, through to nightly movements in the order of several hundred metres to 1 - 2 km.

Life-history strategies and population dynamics of abomasal nematodes in Svalbard reindeer (Rangifer tarandus platyrhynchus)

Parasitology ◽  
2000 ◽  
Vol 120 (3) ◽  
pp. 297-311 ◽  
Author(s):  
R. J. IRVINE ◽  
A. STIEN ◽  
O. HALVORSEN ◽  
R. LANGVATN ◽  
S. D. ALBON
Keyword(s):  
Population Dynamics ◽  
Life History ◽  
Life Histories ◽  
Rangifer Tarandus ◽  
Host Population ◽  
The Arctic ◽  
Life History Strategies ◽  
Late Winter ◽  
Svalbard Reindeer ◽  
Marshallagia Marshalli

The observation that the total abundance of adult nematodes in the abomasum of Svalbard reindeer increases between October and April suggests adaptation to cope with the Arctic winter. Here we investigate the extent to which selection has led to similar life-history strategies in the 3 most numerous trichostrongyle species. The life-histories are found to differ markedly. We use flexible statistical models for the abundance and dispersion of parasites in the host population. One of the taxa, Marshallagia marshalli, was most abundant and had its highest egg output in the winter. In contrast, the abundance of the most common taxa, Ostertagia gruehneri, m. gruehneri was stable or declined from autumn to late winter, and the closely related taxa, O. gruehneri, m. arcticus, showed a similar over winter drop. The faecal egg output of these 2 taxa was highest in summer, as found in temperate trichostrongyle species. Despite the apparent contamination of summer pastures with O. gruehneri, calves showed negligible burdens until their second summer and the abundance of infection reached an asymptote within their third year. In contrast, the abundance of M. marshalli in calves showed a rapid increase over the first summer and by late winter was similar to peak levels found in adults (8000 worms). This increase could not be accounted for by the developing abomasum larvae population and is therefore evidence for transmission over the winter for this taxa. While M. marshalli showed little between-year variation, O. gruehneri showed 2-fold fluctuation in the abundance of infection. O. gruehneri may therefore play a role in the fluctuating population dynamics of the host. Since there was no apparent decline in abundance with host age in any of the 3 taxa there was no evidence of reindeer mounting an immune response.

Sign in / Sign up

Export Citation Format

Share Document