Loss of Nutrients from Catchments and Their Ecological Impacts in the Peel-Harvey Estuarine System, Western Australia

Estuaries ◽  
1992 ◽  
Vol 15 (4) ◽  
pp. 529 ◽  
Author(s):  
Arthur J. McComb ◽  
Robert Humphries
Keyword(s):  
Western Australia ◽  
Ecological Impacts ◽  
Estuarine System

Phosphorus export from coastal plain drainage into the Peel-Harvey estuarine system of Western Australia

1982 ◽  
Vol 33 (1) ◽  
pp. 23 ◽  
Author(s):  
PB Birch
Keyword(s):  
Western Australia ◽  
Coastal Plain ◽  
Dairy Farms ◽  
Dairy Farming ◽  
Benthic Alga ◽  
Clay Soils ◽  
Estuarine System ◽  
Phosphorus Export ◽  
Alluvial Clay

Excessive growth of the benthic alga Cladophora aff. albida in the Peel-Harvey estuarine system has coincided with greatly increased inputs of phosphorus from rivers over the last 20-25 years. At present, about 90%, of phosphorus input is derived from rural coastal plain catchments, where use of superphosphate increased fourfold over the period 1945-1975. The present export of phosphorus from these catchments was found to be positively correlated with rates of superphosphate application, dairy farming, and presence of alluvial clay soils, and negatively correlated with beef farming. Reduction of phosphorus input to the estuary from the coastal plain, therefore, could be achieved by reducing or modifying the present use of superphosphate, and reducing runoff from dairy farms into waterways.

A small dasyurid predator (Sminthopsis virginiae) rapidly learns to avoid a toxic invader

2011 ◽  
Vol 38 (8) ◽  
pp. 726 ◽  
Author(s):  
Jonathan K. Webb ◽  
David Pearson ◽  
Richard Shine
Keyword(s):  
Western Australia ◽  
Small Sample ◽  
Ecological Impacts ◽  
Population Declines ◽  
Cane Toad ◽  
Taste Aversion Learning ◽  
The North ◽  
Formidable Challenge ◽  
Mammalian Predators ◽  
Small Sample Sizes

Context Invasive species are a leading cause of extinctions, yet predicting their ecological impacts poses a formidable challenge for conservation biologists. When native predators are naïve to invaders, they may lack appropriate behaviours to deal with the invader. In northern Australia, the invasion of the highly toxic cane toad (Rhinella marina) has caused serious population declines of reptilian and mammalian predators that are ill equipped to deal with toad toxins. Cane toads recently invaded the Kimberley region of Western Australia, where they potentially threaten several species of small dasyurid predators. Aims We investigated whether red-cheeked dunnarts (Sminthopsis virginiae) attack cane toads, and if so, whether individuals subsequently learn to avoid toads as prey. Methods We quantified feeding and learning behaviours in toad-naïve red-cheeked dunnarts from the north Kimberley in Western Australia. Key results All toad-naïve dunnarts attacked toads during their first encounter. Most dunnarts bit the toad on the snout, killed it by biting the cranium, and consumed the toad snout-first, thereby initially avoiding the toad’s parotoid glands. Most dunnarts partially consumed toads before discarding them, and only one animal showed visible signs of toad poisoning. All dunnarts rapidly learnt to avoid toads as prey after one or two encounters. Predators rejected toads as prey for the duration of the study (22 days), suggesting long-term retention of the knowledge that toads are noxious. Conclusions Our results show that red-cheeked dunnarts rapidly learn to avoid cane toads as prey. Implications Our study was limited by small sample sizes, but our results suggest that small dasyurids can adapt to the cane toad invasion via taste aversion learning.

Eutrophication in the Peel-Harvey Estuarine System, Western Australia

1981 ◽  
pp. 323-342 ◽  
Author(s):  
A. J. McComb ◽  
R. P. Atkins ◽  
P. B. Birch ◽  
D. M. Gordon ◽  
R. J. Lukatelich
Keyword(s):  
Western Australia ◽  
Estuarine System

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.

High predatory efficiency and abundance drive expected ecological impacts of a marine invasive fish

2020 ◽  
Vol 637 ◽  
pp. 195-208 ◽  
Author(s):  
EM DeRoy ◽  
R Scott ◽  
NE Hussey ◽  
HJ MacIsaac
Keyword(s):  
Invasive Species ◽  
Native Species ◽  
Ecological Impact ◽  
Marine Species ◽  
Ecological Impacts ◽  
Negative Effects ◽  
Marine Predator ◽  
Eastern Gulf Of Mexico ◽  
Red Grouper ◽  
Per Capita

The ecological impacts of invasive species are highly variable and mediated by many factors, including both habitat and population abundance. Lionfish Pterois volitans are an invasive marine species which have high reported detrimental effects on prey populations, but whose effects relative to native predators are currently unknown for the recently colonized eastern Gulf of Mexico. We used functional response (FR) methodology to assess the ecological impact of lionfish relative to 2 functionally similar native species (red grouper Epinephelus morio and graysby grouper Cephalopholis cruentata) foraging in a heterogeneous environment. We then combined the per capita impact of each species with their field abundance to obtain a Relative Impact Potential (RIP). RIP assesses the broader ecological impact of invasive relative to native predators, the magnitude of which predicts community-level negative effects of invasive species. Lionfish FR and overall consumption rate was intermediate to that of red grouper (higher) and graysby grouper (lower). However, lionfish had the highest capture efficiency of all species, which was invariant of habitat. Much higher field abundance of lionfish resulted in high RIPs relative to both grouper species, demonstrating that the ecological impact of lionfish in this region will be driven mainly by high abundance and high predator efficiency rather than per capita effect. Our comparative study is the first empirical assessment of lionfish per capita impact and RIP in this region and is one of few such studies to quantify the FR of a marine predator.

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