Factors affecting pitfall capture rates of small ground vertebrates in arid South Australia. II. Optimum pitfall trapping effort

2001 ◽  
Vol 28 (1) ◽  
pp. 61 ◽  
Author(s):  
K. E. Moseby ◽  
J. L. Read

Pitfall trapping is widely used for sampling small terrestrial vertebrates. This study investigated the influence of trapping period, number of trap sites and drift fences on the capture rates of small vertebrates in order to ascertain optimum pitfall trapping efficiency. Capture rates at fenced pits were five times higher than at unfenced pits. Our study indicates that one fenced site established in chenopod shrubland in the Olympic Dam region and trapped for four nights yielded less than one third of the local chenopod shrubland reptile inventory. Capture rates of reptiles at Olympic Dam in arid South Australia were significantly higher on the first three nights of trapping than on the seven subsequent nights. The most efficient number of trap nights for maximising the number of reptile species captured was five nights. Trapping only a single pitfall site per habitat type for 5 nights captured approximately 30% of the reptile species in that habitat compared with 55%, 65% and 73% for three, five and ten sites respectively. Typically, approximately 70% of the reptile species in chenopod shrubland were captured by trapping 5 sites for 7 nights, a method recommended for thorough surveys of species present in chenopod shrublands. Captures of mammals were more variable than those of reptiles and, as a result, sampling of mammal species benefited from more trapping nights than did sampling of reptiles. New mammal species continued to be recorded at a high rate for 8 nights and even 10 sites trapped for 10 nights typically yielded only 60–80% of the species present in chenopod shrubland. Standard 4-night trapping periods adopted by most surveys will fail to detect many rare species, or those that are difficult to trap. Repeated 7-night trapping sessions for up to 21 nights are recommended for surveys where more accurate species inventories are required.

1992 ◽  
Vol 14 (2) ◽  
pp. 143 ◽  
Author(s):  
JL Read

Small mammals, reptiles and amphibians were trapped in pitfalls in a range of habitats around the Olympic Dam Operations mine in central South Australia over a five year period (1987-91) to assess the impacts on these groups of climate, mining and grazing. Neobatrachus centralis, a frog, was the most abundant vertebrate in the region but was only recorded after heavy rains. Reptiles were both diverse and abundant in summer samples and in general maintained their population sizes during droughts. Mammals, however, exhibited considerable fluctuations in population size which were associated with climatic cycles. Sites within the mining lease consistently yielded higher species diversities and capture rates of reptiles than sites in pastoral land, but this could not be related directly to land use.


2015 ◽  
Vol 37 (2) ◽  
pp. 212 ◽  
Author(s):  
John L. Read ◽  
Matthew J. Ward ◽  
Katherine E. Moseby

Optimised detection and sensitivity of fauna-monitoring programs is essential for the adaptive management of threatened species. We describe the influence of trap type, trapping duration and timing on the detection rates of small vertebrates, in particular the nationally endangered sandhill dunnart (Sminthopsis psammophila) in its two primary populations in South Australia. A total of 118 and 155 sandhill dunnarts were captured from the Middleback and Yellabinna regions, respectively, from five trapping sessions between 2008 and 2012. Wide deep pitfall traps (225 mm diameter × 600–700 mm deep) captured significantly more adult sandhill dunnarts than shorter, narrower pitfalls (150 mm diameter × 500 mm deep) or Elliott traps. Deep pitfall traps also captured significantly more hopping mice (Notomys mitchellii) but smaller mammal species were equally trapable in deep or short pitfall traps. Capture rates declined through successive nights of trapping. Capture rates of sandhill dunnarts were greatest in one study region when the moon illumination was less than 40% compared with fuller moon phases but were not affected by moon illumination in the other study region. The results suggest that higher capture rates of sandhill dunnarts will be achieved when using wide, deep pitfall traps on dark nights during the first two nights of trapping. Trapping in summer detected more juvenile sandhill dunnarts than trapping in winter.


2017 ◽  
Vol 39 (2) ◽  
pp. 205 ◽  
Author(s):  
Elizabeth Thornett ◽  
Bertram Ostendorf ◽  
David A. Taggart

Burrows can provide refuge for both burrowing and non-burrowing species within harsh environments through protection from climatic extremes, water loss and predation. In Australia, however, despite having a rich diversity of burrowing mammals, little is known about the use of burrows by non-burrowing species. This study aimed to identify the extent of co-use of southern hairy-nosed wombat (Lasiorhinus latifrons) burrows on Wedge Island off the coast of South Australia. Burrow use was monitored using 34 motion-activated cameras placed outside wombat burrows between March and September 2015. Eleven species were found to use burrows, with six commensal species observed using burrows on numerous occasions. These included two mammal species (black-footed rock-wallaby, Petrogale lateralis pearsoni; brush-tailed bettong, Bettongia penicillata), three reptile species (peninsula dragon, Ctenophorus fionni; southern sand-skink, Liopholis multiscutata; White’s skink, Liopholis whitii), and one avian species (little penguin, Eudyptula minor). The most common species observed using burrows was the black-footed rock-wallaby, which was recorded using burrows 1795 times. Observations of wombats using burrows were made 1674 times. The prevalent use of burrows on Wedge Island by species other than wombats is an observation with potentially important and broad ecological, conservation, and management implications across Australia’s arid and semiarid zones.


2020 ◽  
Vol 47 (8) ◽  
pp. 570
Author(s):  
David A. Roshier ◽  
Felicity L Hotellier ◽  
Andrew Carter ◽  
Leah Kemp ◽  
Joanne Potts ◽  
...  

Abstract ContextThe success of conservation fences at protecting reintroduced populations of threatened mammals from introduced predators has prompted an increase in the number and extent of fenced exclosures. Excluding introduced species from within conservation fences could also benefit components of insitu faunal assemblages that are prey for introduced predators, such as reptiles and small mammals. Conversely, reintroduced mammals may compete with smaller mammals and reptiles for resources, or even prey on them. AimsIn a 10-year study from 2008, we examine how small terrestrial vertebrates respond to the exclusion of introduced predators, the feral cat (Felis catus) and red fox (Vulpes Vulpes), introduced herbivores and the reintroduction of regionally extinct mammal species. MethodsDifferences in the yearly relative abundance of reptiles and mammals according to habitat type and whether sites were fenced or not, were tested using multivariate generalised linear models. Next, we calculated univariate P-values to identify individual species that showed significant relationships, positive and negative, with any of the explanatory variables. Key resultsTotal captures of reptiles were lower inside the conservation fence in all years, whereas total captures of small mammals were markedly higher inside the fenced area, notably in dasyurids. ConclusionOur results showed that conservation fences can deliver benefits for some fauna (but not all) beyond facilitating the reintroduction of highly threatened mammals. ImplicationsOur results demonstrated the consequential impacts of introduced predators on the Australian small mammal fauna, and showed that predator-exclusion fences can be an effective conservation intervention for this guild.


2018 ◽  
Vol 11 (1) ◽  
pp. 14-24
Author(s):  
Chabi A.M.S. Djagoun ◽  
Etotépé A. Sogbohossou ◽  
Barthélémy Kassa ◽  
Christian B. Ahouandjinou ◽  
Hugues A. Akpona ◽  
...  

Background: The habitat degradation together with fragmentation and illegal hunting represent a major threat for biodiversity conservation in Lama protected areas. Method: We used a combination of questionnaire survey with local communities for ranking the hunted mammal species as bushmeat and track surveys in gridded-cell system of 500x500 m2 (n=268) to assess at what extend the management design, the anthropogenic factors and habitat type affect the occupancy model of those mammal species. Results: Twenty mammal species have been predominantly reported by the local inhabitants to consume bushmeat species and 5 of them have been identified as the most preferable as hunted game mammals. The selection of the preferred habitat among the swampy forest, the dense forest, the tree plantations and cropland for the prioritized game species varies between species but looks similar when grouping in different orders. Some bushmeat species were found to select the more secure habitat (natural forest); suggesting the zoning system in the Lama forest can passively protect those species. However, some species such as T. swinderianus although highly hunted showed preference to anthropogenic habitat, avoiding the well secured core zone in Lama Forest. Conclusion: Our findings highlighted the importance of the zoning system with different management objectives in the habitat occupancy model of the highly hunted wildlife species.


Oryx ◽  
2005 ◽  
Vol 40 (1) ◽  
pp. 95-102 ◽  
Author(s):  
Richard Engeman ◽  
Desley Whisson ◽  
Jessica Quinn ◽  
Felipe Cano ◽  
Pedro Quiñones ◽  
...  

Critically Endangered Puerto Rican parrots Amazona vittata are one of the rarest birds in the world. Several exotic mammal species capable of preying on Puerto Rican parrots cohabit the Caribbean National Forest with the only wild population of these parrots. We used tracking plates, monitoring blocks and trapping to index black rats, small Indian mongooses and feral cats in parrot habitat and in public-use areas in the same habitat type. We had high trap success for black rats at all sites (42% of all sites combined), among the highest reported in the world. Rat response to monitoring (nontoxic bait) blocks was universally high, regardless of ground or tree placement. Mongooses were present at all sites, with a greater proportion of plates tracked within the forest than at public-use sites. Cats were present at all forest sites and one of the public-use sites. Presence of the three species did not appear to be linked to human disturbance. Because only 30–40 Puerto Rican parrots survive in the wild, with as few as three pairs nesting in 2002, we concluded that the abundance and pervasiveness of exotic mammalian predators poses a greater threat to the parrots than has been generally acknowledged. This is evidenced by mammalian predation during recent parrot breeding seasons, including six fledglings taken by mongooses and one nest failure from rats during 2000–2003.


1998 ◽  
Vol 46 (6) ◽  
pp. 617 ◽  
Author(s):  
J. L. Read

Ctenotus skinks are the most diverse and abundant diurnal reptile genus at Olympic Dam, in the South Australian arid zone. The home range, demography, reproduction and diet of five syntopic Ctenotus species was studied over a 6-year period in chenopod shrubland. Longevity frequently exceeded three years in C. regius, four years in C. schomburgkii and five years in C. leonhardii, with a 7-year-old specimen of C. leonhardii being recorded. Females of most species tended to be larger and lived longer than males. Two eggs were typically laid by each species in early summer. Annual reproductive effort, particularly in C. leonhardii, varied considerably depending upon the prevailing environmental conditions. All local species apparently occupied home ranges, with maximum recapture radii in different species of 40–60 m. Ctenotus appear to be unspecialised insectivores, although plant material and lizards are sometimes eaten by the larger species.


2020 ◽  
Vol 115 (8) ◽  
pp. 1855-1870 ◽  
Author(s):  
Liam Courtney-Davies ◽  
Cristiana L. Ciobanu ◽  
Simon R. Tapster ◽  
Nigel J. Cook ◽  
Kathy Ehrig ◽  
...  

Abstract Establishing timescales for iron oxide copper-gold (IOCG) deposit formation and the temporal relationships between ores and the magmatic rocks from which hydrothermal, metal-rich fluids are sourced is often dependent on low-precision data, particularly for deposits that formed during the Proterozoic. Unlike accessory minerals routinely used to track hydrothermal mineralization, iron oxides are dominant components of IOCG systems and are therefore pivotal to understanding deposit evolution. The presence of ubiquitous, magmatic-hydrothermal U-(Pb)-W-Sn-Mo–bearing zoned hematite resolves a range of geochronological issues concerning formation of the ~1.6 Ga Olympic Dam IOCG deposit, South Australia, at up to ~0.05% precision (207Pb/206Pb weighted mean; 2σ) using isotope dilution-thermal ionization mass spectrometry (ID-TIMS). Coupled with chemical abrasion-ID-TIMS zircon dates from host granite and volcanic rocks within and enclosing the ore-body, a confident magmatic-hydrothermal chronology is defined. The youngest zircon date from the granite intrusion hosting Olympic Dam indicates magmatism was occurring up until 1593.28 ± 0.26 Ma. The orebody was principally formed during a major mineralizing event following granite uplift and during cupola collapse, whereby the hematite with the oldest age is recorded in the outer shell of the deposit at 1591.27 ± 0.89 Ma, ~2 m.y. later than the youngest documented magmatic zircon. Hematite dates captured throughout major lithologies, different ore zones, and the ~2-km vertical extent of the deposit support ~2 m.y. of hydrothermal activity. New age constraints on the spatial-temporal evolution of the formation of Olympic Dam are considered with respect to a mantle to crustal continuum model. Cyclical tapping of magma reservoirs to maintain crystal mushes for extended time periods and incremental building of batholiths on the million-year scale prior to main mineralization pulses can explain the ~2-m.y. temporal window temporal window inferred from the data. Despite the challenge of reconciling such an extended window with contemporary models for porphyry deposits (≤1 m.y.), formation of Proterozoic ore deposits has been addressed at high-precision and supports the case that giant IOCG deposits may form over millions of years.


Sign in / Sign up

Export Citation Format

Share Document