Status of warru (Petrogale lateralis MacDonnell Ranges race) in the Anangu Pitjantjatjara Yankunytjatjara Lands of South Australia. 2. Population dynamics

2011 ◽  
Vol 33 (2) ◽  
pp. 142 ◽  
Author(s):  
Matthew J. Ward ◽  
Laura Ruykys ◽  
Jason van Weenen ◽  
Siobhan de Little ◽  
Anika Dent ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Red Fox ◽  
South Australia ◽  
Free Water ◽  
Juvenile Survival ◽  
Winter Rainfall ◽  
Population Sizes ◽  
Access To Water ◽  
Survey Results ◽  
Reproductive Rates

The population dynamics of warru (Petrogale lateralis MacDonnell Ranges race) were studied in the Anangu Pitjantjatjara Yankunytjatjara Lands, South Australia, in order to inform management and better understand the race’s conservation ecology. Mark–recapture between 2005 and 2010 at the three largest known remaining colonies, followed by POPAN modelling, indicated that population sizes were 23 at New Well and 24 at Alalka in the Musgrave Ranges, and 14 at Kalka in the Tomkinson Ranges. Taking into account recent survey results, the study confirmed that warru are ‘Endangered’ in South Australia. However, there is potential for the recovery of the race, with high average reproductive rates (in the Musgrave Ranges >90% of reproductively active females had pouch young), even sex ratios and relatively high adult survivorship (>75%). Juvenile survival (51%), however, was significantly lower than that of adults. Given that red fox (Vulpes vulpes) numbers are low at these sites, this is possibly due to predation by feral cats (Felis catus), although this needs further investigation. Juvenile survival was also positively correlated with winter rainfall, possibly indicating that access to water is important during the drier winter months. In light of these observations, it is proposed that management of remaining warru colonies focus on cat control and consider providing access to free water during winter, as well as addressing landscape-scale threats such as wildfire and the spread of exotic plants.

scholarly journals Red fox sex ratio and changes in the number in the Krasnoarmeisky District of the Samara Region

2018 ◽  
Vol 7 (2) ◽  
pp. 111-115
Author(s):  
Olga Aleksandrovna Sklueva ◽  
Valeriy Vitalyevich Sklyuev ◽  
Rafik Ibragimovich Khakimov
Keyword(s):  
Population Dynamics ◽  
Sex Ratio ◽  
Vulpes Vulpes ◽  
Red Fox ◽  
Direct Impact ◽  
Age Composition ◽  
Behavioral Adaptations ◽  
Epizootic Process ◽  
Males And Females ◽  
Homeostatic State

The paper presents some data on the red fox ( Vulpes vulpes , Linnaeus, 1758) sex ratio in the Krasnoarmeysky District of the Samara Region. The results of winter trails traces of mammals show the placement of individual sites of males and females. The authors consider relationship between the population dynamics, sex and age composition and the placement of individual sites. Some aspects of behavioral adaptations and causes of changes in the number of animals in the study area are considered. The influence of a poaching factor on the dynamic indicators of the studied population and the possible danger of the epizootic process is described. A comparative analysis with the previously obtained data on the ratio of males and females in the litter is carried out. The paper indicates possible causes of animals number changes in the study areas. Poaching has a direct impact on the studied population homeostatic state maintaining mechanisms. There is also a forecast of poaching influence on deterioration of epidemiological and epizootic situation in the investigated region. In this paper we give recommendations to minimize possible damage by human activities.

Population Dynamics of White Sharks in Spencer Gulf, South Australia

1996 ◽  
pp. 401-414 ◽  
Author(s):  
WESLEY R. STRONG ◽  
DONALD R. NELSON ◽  
BARRY D. BRUCE ◽  
RICHARD D. MURPHY
Keyword(s):  
Population Dynamics ◽  
South Australia

Population Dynamics and Movement Patterns of Bolam's Mouse, Pseudomys bolami, at Roxby Downs, South Australia.

1998 ◽  
Vol 20 (3) ◽  
pp. 353
Author(s):  
K.E. Moseby ◽  
J.L. Read
Keyword(s):  
Arid Zone ◽  
Sand Dunes ◽  
South Australia ◽  
Breeding Strategy ◽  
Early Summer ◽  
Ecological Data ◽  
Winter Rainfall ◽  
Land Systems ◽  
Single Night ◽  
Time Of Year

Basic ecological data were collected on Bolam's mouse, Pseudomys bolami, during a six year trapping study at Roxby Downs in northern South Australia. Pseudomys bolami inhabited mixed arid land systems in the Roxby Downs area, sheltering in the longitudinal orange sand dunes but foraging at night principally on the adjacent chenopod swales. Distances of up to 334m were traversed in a single night and recapture rates were high within trapping sessions but low between sessions suggesting wide-ranging movements and short-term residency. Dietary observations imply an omnivorous diet. Whilst the closely related P. hermannsburgensis is regarded as having an opportunistic breeding strategy, P. bolami reproduced opportunistically but also regularly in spring and early summer. Different reproductive strategies may be influenced by the latitudinal distribution of P. bolami near the southern margin of the arid-zone, where rainfall can occur at any time of year but winter rainfall is more predictable. This contrasts with P. hermannsburgensis, which inhabits more northerly arid areas where rainfall is erratic and unpredictable. There was a 10 fold fluctuation in P. bolami captures over the trapping period with numbers of P. bolami and house mice, Mus domesticus peaking 12 months after above average rains during 1992. Rodent captures remained high for two years afterwards. Although P. bolami persisted throughout the study period, M. domesticus was only present when conditions were above average. Trap success of P. bolami or M. domesticus did not vary between the five sub habitats at the 1 ha study site. However, trap success of P. bolami was positively related to vegetation cover, particularly cover of low bluebush, Maireana astrotricha. Maireana astrotricha may be important in providing both food and cover for P. bolami, a scenario consistent with the utilisation of spinifex, Triodia spp. by P. hermannsburgensis in the northern arid-zone. Past over- grazing of chenopod shrublands may have reduced cover and contributed to the suggested decline in the distribution of P. bolami.

Dormancy in Caladenia: a Bayesian approach to evaluating latency

2009 ◽  
Vol 57 (4) ◽  
pp. 340 ◽  
Author(s):  
Raymond L. Tremblay ◽  
Maria-Eglée Perez ◽  
Matthew Larcombe ◽  
Andrew Brown ◽  
Joe Quarmby ◽  
...  
Keyword(s):  
Bayesian Approach ◽  
Transition Probabilities ◽  
South Australia ◽  
C Elegans ◽  
Emergent Plants ◽  
Terrestrial Orchids ◽  
State Capture ◽  
Population Sizes ◽  
Capture Recapture ◽  
One Year

Dormancy is common in many terrestrial orchids in southern Australia and other temperate environments. The difficulty for conservation and management when considering dormancy is ascertaining whether non-emergent plants are dormant or dead. Here we use a multi-state capture–recapture method, undertaken over several seasons, to determine the likelihood of a plant becoming dormant or dying following its annual emergent period and evaluate the frequency of the length of dormancy. We assess the transition probabilities from time series of varying lengths for the following nine terrestrial orchids in the genus Caladenia: C. amoena, C. argocalla, C. clavigera, C. elegans, C. graniticola, C. macroclavia, C. oenochila, C. rosella and C. valida from Victoria, South Australia and Western Australia. We used a Bayesian approach for estimating survivorship, dormancy and the likelihood of death from capture–recapture data. Considering all species together, the probability of surviving from one year to the next was ~86%, whereas the likelihood of observing an individual above ground in two consecutive years was ~74%. All species showed dormancy of predominantly 1 year, whereas dormancy of three or more years was extremely rare (<2%). The results have practical implications for conservation, in that (1) population sizes of Caladenia species are more easily estimated by being able to distinguish the likelihood of an unseen individual being dormant or dead, (2) population dynamics of individuals can be evaluated by using a 1–3-year dormancy period and (3) survey effort is not wasted on monitoring individuals that have not emerged for many years.

Effects of Sheep Grazing Astrebla Grasslands in Central Western Queensland. Iii. Dynamics of Astrebla Spp. Under Grazing and Exclosure Between 1975 and 1986.

1991 ◽  
Vol 13 (1) ◽  
pp. 36 ◽  
Author(s):  
DM Orr ◽  
CJ Evenson
Keyword(s):  
Population Dynamics ◽  
Seed Production ◽  
Basal Area ◽  
Summer Rainfall ◽  
High Variability ◽  
Plant Population ◽  
Sheep Grazing ◽  
Plant Population Dynamics ◽  
Winter Rainfall ◽  
Plant Populations

The basal area, yield and plant populations of Astrebla spp. were monitored under grazing and exclosure in Astrebla grasslands between 1975 and 1986. This study was undertaken to develop an understanding of how Astrebla spp. respond to grazing, particularly in relation to the high variability of rainfall. Basal area and yield of Astrebla spp. varied widely between years in response to summer rainfall, with few differences between exclosure and grazing. The failure of summer rainfall resulted in increased utilization of Astrebla spp. but this effect was partially offset in some years by the growth of forb species following winter rainfall. Grazing stimulated the recruitment of Astrebla spp. seedlings by increasing the density of inflorescences which, in turn, increased seed production. Survival of seedling cohorts depended on adequate summer rainfall and grazing tended to enhance cohort survival. There was a greater plant flux under grazing than under exclosure. It was concluded that rainfall is the major factor influencing the biomass and plant population dynamics of Astrebla spp. and that grazing up to about 30% utilization is not detrimental to Astrebla spp.

scholarly journals The Influence of Climate on Foliar Symptoms of Eutypa Dieback in Grapevines

2007 ◽  
Vol 97 (10) ◽  
pp. 1284-1289 ◽  
Author(s):  
M. R. Sosnowski ◽  
D. Shtienberg ◽  
M. L. Creaser ◽  
T. J. Wicks ◽  
R. Lardner ◽  
...  
Keyword(s):  
Climatic Factors ◽  
Disease Incidence ◽  
South Australia ◽  
Symptom Expression ◽  
Winter Rainfall ◽  
Eutypa Lata ◽  
Eutypa Dieback ◽  
Foliar Symptoms ◽  
Geographical Regions ◽  
Very High

Foliar symptoms of Eutypa dieback, caused by Eutypa lata, in grapevines, cv. Shiraz, varied from year to year in a 6-year study conducted in South Australia and, although trends were similar for vineyards within geographical regions, differences were observed between regions. We attempted to elucidate the causes underlying this variation and hypothesized that it was influenced by climatic factors. A number of possible relationships were identified between climate and symptom expression: (i) increased symptom expression was related to increased winter rainfall 18 months earlier, (ii) decreased disease incidence and prevalence were related to increased temperature in spring, and (iii) a reduction in disease incidence was related to both very high and very low rainfall in October. Theories for these relationships are proposed and require further investigation. A conceptual model was developed which requires validation and has the potential to predict the incidence of foliar symptoms of Eutypa dieback. Information from this study could lead to an improved integrated pest management system to suppress foliar symptoms and sustain productivity of vines infected with E. lata.

scholarly journals Cyclic dynamics of snowshoe hares on a small island in the Yukon

2002 ◽  
Vol 80 (8) ◽  
pp. 1442-1450 ◽  
Author(s):  
Charles J Krebs ◽  
Todd N Zimmerling ◽  
Claire Jardine ◽  
Kim A Trostel ◽  
Alice J Kenney ◽  
...  
Keyword(s):  
Population Decline ◽  
Survival Rates ◽  
Ground Squirrels ◽  
Adult Survival ◽  
Small Island ◽  
Juvenile Survival ◽  
Lower Amplitude ◽  
Arctic Ground Squirrels ◽  
Reproductive Rates ◽  
Survival Differences

Snowshoe hare (Lepus americanus) populations were monitored from 1977 to 2001 on Jacquot Island (5 km2) in Kluane Lake, southwestern Yukon, and on nearby mainland sites. Jacquot Island hares averaged twice the density of mainland control populations and, although they show 10-year cycles, fluctuate with much lower amplitude than mainland populations. Three separate intensive studies over 6 years attempted to determine what caused these differences. We tested two hypotheses to explain the dynamics. Reproductive rates of hares were similar on Jacquot Island and the mainland. Adult survival rates were higher on the island in most years, with the exception of years of population decline. Juvenile survival rates from 0 to 30 days of life were much higher on the island than on the mainland except for decline summers. The adult- and juvenile-survival differences between the island and the mainland were explained most consistently by predation. Improved survival on the island is correlated with a reduction in the numbers and types of predators found on Jacquot Island compared with the mainland. In particular, red squirrels were rare on Jacquot Island, arctic ground squirrels were absent, and the larger predators, like lynx and great-horned owls, were sporadic in occurrence on this small island.

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