Changes in Species Composition of Floras on Islets Near Perth, Western Australia

1980 ◽  
Vol 7 (4) ◽  
pp. 399 ◽  
Author(s):  
Ian Abbott ◽  
Robert Black
Keyword(s):  
Species Composition ◽  
Western Australia

The germinable soil seedbank of Eucalyptus victrix grassy woodlands at Roy Hill station, Pilbara district, Western Australia

2004 ◽  
Vol 26 (1) ◽  
pp. 17 ◽  
Author(s):  
R. A. Graham ◽  
S. K. Florentine ◽  
J. E. D. Fox ◽  
T. M. Luong
Keyword(s):  
Species Composition ◽  
Western Australia ◽  
Perennial Grass ◽  
Summer Rainfall ◽  
Distribution Patterns ◽  
Grass Species ◽  
Surface Areas ◽  
Hill Station ◽  
Soil Seedbank ◽  
Germinable Seed

The paper reports soil seedbank species composition, of Eucalyptus victrix grassy woodlands, of the upper Fortescue River in the Pilbara District, Western Australia. In this study, our objectives were to investigate germinable soil seedbanks and species composition in response to three simulated seasons, using emergence. Variation in seed density from three depths was tested. Four field sites were sampled. Thirty samples were collected in late spring, after seed rain and before summer rainfall. From each sample spot, three soil depths (surface, 1–5, and 6–10 cm) were segregated from beneath surface areas of 100 cm2. Samples were later incubated in a glasshouse to simulate three different seasonal conditions (autumn, winter and spring). Germinating seedlings were recorded on emergence and grown until identified. Forty-one species germinated, comprising 11 grasses (7 annuals and 4 perennials), 25 annual herbs and 5 perennial herbs. Distribution patterns of germinable seed in both the important annual grass Eragrostis japonica and the perennial Eragrostis setifolia (a preferred cattle fodder species), suggest that seedbank accumulation differs among species and between sites. In part, this may be associated with the absence of grazing. Species with most total germinable seed were E. japonica (Poaceae; 603/m2), and the annual herbs Calotis multicaulis (Asteraceae; 346/m2), and Mimulus gracilis (Scrophulariaceae; 168/m2). Perennial grass seed was sparse. Spring simulation gave most germination (1059), followed by autumn (892) and winter (376) sets. Greatest species diversity was produced from the spring simulation (33 species), followed by autumn (26), and winter (22). Of the total germination, 92% came from 17 species that were represented in all three simulations. Of the 1227 grass seedlings counted, most were recruited from the surface soil (735), followed by the 5 (310) and 10 (182) cm depths. Marginally more grass seedlings germinated from the spring simulation (558) than the autumn set (523). Only 11.9% of grass germinants came from the winter simulation. All grass species recruited from the soil seedbanks had a C4 photosynthetic pathway. Except for Cenchrus ciliaris all grass species are native to Australia. Of the four sites sampled, one fenced to exclude cattle five years earlier had significantly more germination than the three unfenced sites. Seedbank sampling produced several new records for plants in the areas sampled.

Changes in an Assemblage of Small Birds in the Understorey of Dry Sclerophyll Forest in Southwestern Australia After Fire

1988 ◽  
Vol 15 (3) ◽  
pp. 331 ◽  
Author(s):  
RD Wooller ◽  
MC Calver
Keyword(s):  
Species Composition ◽  
Western Australia ◽  
Southwestern Australia ◽  
Low Intensity ◽  
Sclerophyll Forest

Changes in the numbers and types of small birds caught in mist-nets in the understorey of dry sclerophyll forest in south-western Australia were recorded for three years after a low intensity fire. There were few changes in the species composition of the assemblage but abundances of the 6-8 most numerous and relatively sedentary species were approximately halved. Many marked individuals (22%) were recaptured up to three years after the fire. After the fire, the number of prey taxa recorded from the faeces of birds caught fell from twelve to six, and the birds ate proportionately more ants and fewer beetles. Ants eaten after the fire were smaller than those eaten before it.

Catching characteristics of four fish-trap types on the North West Shelf of Australia

1991 ◽  
Vol 42 (4) ◽  
pp. 369 ◽  
Author(s):  
AW Whitelaw ◽  
KJ Sainsbury ◽  
GJ Dews ◽  
RA Campbell
Keyword(s):  
Species Composition ◽  
Western Australia ◽  
Commercial Catch ◽  
North West ◽  
Fish Trap ◽  
The North ◽  
Significant Difference ◽  
Trap Fishery ◽  
Catch Rates ◽  
North Western

Commercial catch rates for the North West Shelf trap fishery, at up to 10 kg trap-1 h-1, are considerably greater than those reported for similar trap fisheries elsewhere. Two fish-trapping experiments were conducted off Lowendal Island (north-western Australia) to study the catch rates of four trap types (O-, S- and Z-shaped and rotational) and two bait types (pilchard, Sardinops neopilchardus, and emperor, Lethrinus choerorynchus) over various soak times (ranging from 1 to 24 h). Total catches varied significantly with soak time. Catches increased rapidly for the first 3 h, levelled off, and then decreased steadily to 16 h; there was a slight increase at 24 h. The species composition of the catch did not vary significantly with soak time. There was no significant difference in catch rates between trap types. The traps did not appear to cause fish to die by being confined in the traps for extended periods. A fairly large amount of suitable bait (about 4 kg) was necessary for effective trapping of fish. The catch rates of the pilchard bait were significantly higher than those of the emperor bait. Over extended soak times (more than 3 h), pilchard bait was lost at a rate of about 6% h-1. whereas there was no detectable loss of emperor bait.

Geology is a significant indicator of algal cover and invertebrate species composition on intertidal reefs of Ngari Capes Marine Park, south-western Australia

2019 ◽  
Vol 70 (2) ◽  
pp. 270 ◽  
Author(s):  
C. Bessey ◽  
M. J. Rule ◽  
M. Dasey ◽  
A. Brearley ◽  
J. M. Huisman ◽  
...  
Keyword(s):  
Species Composition ◽  
Western Australia ◽  
Rocky Intertidal ◽  
Underlying Structure ◽  
Effective Management ◽  
Bare Rock ◽  
Marine Park ◽  
Invertebrate Biodiversity ◽  
Invertebrate Composition ◽  
Number Of Individuals

Effective management of rocky intertidal reefs requires an understanding of spatial variation in species composition and abundance, and the identification of high biodiversity areas. This study identified patterns of invertebrate biodiversity on intertidal reefs of differing underlying structure within Ngari Capes Marine Park, south-west Western Australia. Intertidal reef surveys were conducted at 12 limestone and 9 granite sites throughout the park. Geology was a significant indicator of variation in percentage cover of substrate and invertebrate composition, which covaried with rugosity and complexity. Limestone reefs were characterised by a combination of high and low branching algae and a sand–turf matrix, whereas granite reefs consisted of bare rock. A total of 15772 individual invertebrates representing 10 phyla, 16 classes, 60 families and 121 species was recorded. A high abundance of dove (Family Columbellidae) and jewel top snails (Family Trochidae) characterised limestone reefs, whereas an assortment of limpets and chitons characterised granite reefs. Granite reefs contained more species (92v. 63) and a higher mean (±s.d.) number of individuals (119±58v. 42±79m–2) than did limestone reefs. These findings emphasise the effect of underlying geology on the distribution of intertidal invertebrates and the need for management programs to accommodate different habitat types to effectively conserve biodiversity.

Keeping children at home safely: A statutory agency's quest in Western Australia

2013 ◽  
Author(s):  
Helen McMahon ◽  
Katherine Fendley
Keyword(s):  
Western Australia ◽  
At Home

Persistence of giants: population dynamics of the limpet Scutellastra laticostata on rocky shores in Western Australia

2020 ◽  
Vol 646 ◽  
pp. 79-92
Author(s):  
RE Scheibling ◽  
R Black
Keyword(s):  
Population Dynamics ◽  
Western Australia ◽  
Size Structure ◽  
Survival Rates ◽  
Maximum Size ◽  
High Rate ◽  
Adult Survival ◽  
Rocky Shores ◽  
Adult Size ◽  
Decadal Time Scale

Population dynamics and life history traits of the ‘giant’ limpet Scutellastra laticostata on intertidal limestone platforms at Rottnest Island, Western Australia, were recorded by interannual (January/February) monitoring of limpet density and size structure, and relocation of marked individuals, at 3 locations over periods of 13-16 yr between 1993 and 2020. Limpet densities ranged from 4 to 9 ind. m-2 on wave-swept seaward margins of platforms at 2 locations and on a rocky notch at the landward margin of the platform at a third. Juvenile recruits (25-55 mm shell length) were present each year, usually at low densities (<1 m-2), but localized pulses of recruitment occurred in some years. Annual survival rates of marked limpets varied among sites and cohorts, ranging from 0.42 yr-1 at the notch to 0.79 and 0.87 yr-1 on the platforms. A mass mortality of limpets on the platforms occurred in 2003, likely mediated by thermal stress during daytime low tides, coincident with high air temperatures and calm seas. Juveniles grew rapidly to adult size within 2 yr. Asymptotic size (L∞, von Bertalanffy growth model) ranged from 89 to 97 mm, and maximum size from 100 to 113 mm, on platforms. Growth rate and maximum size were lower on the notch. Our empirical observations and simulation models suggest that these populations are relatively stable on a decadal time scale. The frequency and magnitude of recruitment pulses and high rate of adult survival provide considerable inertia, enabling persistence of these populations in the face of sporadic climatic extremes.

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