Drought increases the impact of introduced European foxes on breeding Australian pelicans

2016 ◽  
Vol 43 (6) ◽  
pp. 507 ◽  
Author(s):  
Gregory R. Johnston
Keyword(s):  
Path Analysis ◽  
South Australia ◽  
Breeding Population ◽  
Population Declines ◽  
Egg Mortality ◽  
Eradication Program ◽  
Introduced Predators ◽  
Mammalian Predators ◽  
Colonial Waterbirds ◽  
The Impact

Context Introduced mammalian predators have been responsible for population declines in native prey species around the world. Many conservation programs rely on control or eradication of introduced mammalian predators, but the impact of environmental variation on the efficacy of this approach is rarely documented. Aims The present paper describes (1) the impact of introduced European foxes (Vulpes vulpes) on breeding Australian pelicans (Pelecanus conspicillatus) in South Australia and (2) the responses of both species to a fox-eradication program using a before-after-impact framework. Methods The impact of foxes on breeding Australian pelicans was studied on a near-shore island. An index of fox abundance and direct measurements of breeding pelicans and mortality of pelican eggs and young were compared before foxes were established on the island, while foxes were resident and during a fox-eradication program. A path analysis was used to explore the causal relationships between fox abundance and other potential covariates (e.g. rainfall) on breeding pelicans. Key results Before foxes were established on the island, the number of breeding pelicans grew and egg mortality was low. While foxes were resident, the number of breeding pelicans fell and egg mortality rose. This was followed by an increase in the number of breeding pelicans and a decrease in egg mortality during a fox-eradication program. While foxes had a clear impact on egg mortality, a period of low rainfall also occurred while foxes were resident. The path analysis showed an interaction among rainfall, size of the pelican breeding population and the impact of foxes. In drought years, fewer pelicans bred and foxes were a major cause of nest abandonment when they entered pelican breeding colonies to prey on eggs. Conclusions These results confirmed that foxes can be an important predator of ground-nesting, colonial waterbirds, and showed that the impact of foxes may be higher in drought years when prey populations are low. Implications The present study suggests that an increase in the incidence of droughts as a result of climate change may increase the impact of introduced predators on drought-sensitive waterbirds and raises the possibility of focussing predator-control efforts during droughts, as periods of particular risk to colony-breeding waterbirds.

Colony relocation of Greater Crested Terns Thalasseus bergii in Bass Strait, south-eastern Australia

2020 ◽  
Vol 37 ◽  
pp. 166-171
Author(s):  
Aymeric Fromant ◽  
◽  
Yonina Eizenberg ◽  
Rosalind Jessop ◽  
Arnaud Lec’hvien ◽  
...  
Keyword(s):  
Prey Availability ◽  
South Australia ◽  
Barrier Islands ◽  
Breeding Population ◽  
Storm Events ◽  
Jack Mackerel ◽  
Seabird Species ◽  
Eastern Australia ◽  
Environmental Variations ◽  
The Impact

A newly established Greater Crested Tern Thalasseus bergii colony was observed on Kanowna Island, northern Bass Strait, in December 2019 and was monitored through January 2020. A maximum of 532 ± 28 nests was counted,representing ~15–20% of the known northern Bass Strait breeding population. Resightings of 69 leg-banded individuals (from 3 to 24 years of age) demonstrated that founding individuals originated from colonies in Victoria [The Nobbies on Phillip Island (54%), Corner Inlet Barrier Islands (39%), Mud Islands in Port Phillip Bay (6%)] and one individual from South Australia. Breeding began 2 months later than usual for northern Bass Strait, perhaps because the birds only moved to Kanowna Island after failed nesting attempts elsewhere (Corner Inlet and Phillip Island). Individuals were observed to mainly feed their chicks with Barracouta Thyrsites atun and Jack Mackerel Trachurus declivis, contrasting with the usual predominance of Australian Anchovy Engraulis australis in the diet of this species in the Bass Strait region. This relocation may result from local changes in prey availability and/or a combination of potential human disturbance, predation and storm events. The recent 50% decrease in the number of breeding Greater Crested Terns in Victoria suggests substantial changes in the regional environmental conditions, highlighting the importance of understanding the impact of environmental variations on seabird species.

Impact of rabbit haemorrhagic disease on introduced predators in the Flinders Ranges, South Australia

2002 ◽  
Vol 29 (6) ◽  
pp. 615 ◽  
Author(s):  
C. Holden ◽  
G. Mutze
Keyword(s):  
Population Dynamics ◽  
Physical Condition ◽  
South Australia ◽  
Feral Cats ◽  
Flinders Ranges ◽  
Introduced Predators ◽  
Rabbit Haemorrhagic Disease ◽  
Haemorrhagic Disease ◽  
The Impact

The impact of rabbit haemorrhagic disease (RHD) on the population dynamics and diet of foxes and feral cats was studied in the Flinders Ranges, South Australia. Populations of both foxes and cats decreased substantially some 6–10 months after the advent of RHD, when rabbit numbers were reduced by 85%. The diet of foxes changed as a result of reduced rabbit numbers, with much less rabbit and more invertebrates and carrion being eaten. The physical condition of foxes showed little change after RHD. The diet of cats did not change markedly, but their physical condition was substantially poorer than before RHD. Total predation on native fauna is considered to have decreased after RHD.

The impact of mammalian insectivores Rattus rattus (Rat), Mus musculus (Mouse) & Erinaceus europeus (Hedgehog) on the size and abundance of mainland Coleoptera and Orthoptera

2021 ◽  
Author(s):  
◽  
Thomas Hewitt
Keyword(s):  
Mus Musculus ◽  
Rattus Rattus ◽  
Temporal Analysis ◽  
Invertebrate Communities ◽  
Introduced Predators ◽  
Mammalian Predators ◽  
Study Sites ◽  
Tree Weta ◽  
Occupancy Rates ◽  
The Impact

<p>The impact of introduced mammalian predators on indigenous vertebrates is relatively well documented, however the general responses of indigenous invertebrate communities is less well known. Many indigenous invertebrates, particularly the large flightless species such as those in the genus Deinacrida (Orthoptera) and Anagotus (Curculionidae) have been extirpated from much of their range due largely to the impacts of introduced predators. Despite these well-known examples very little is known about the general impact of introduced predators on invertebrate communities. Beginning in 2012 pitfall traps and artificial wētā motels were established across seven study sites in the Aorangi and Remutaka ranges east of Wellington alternately baited with squid and monitored two to three times annually. Mammal tracking took place in the form of tracking tunnels giving three mammal indexes for rats (Rattus rattus), mice (Mus musculus) and hedgehogs (Erinaceus europeus). Cavity dwelling wētā in wētā motels were measured and counted in situ whilst pitfall trapped Coleoptera and Orthoptera were transported to the lab for measuring and identification. Linear mixed effects model, type 3 ANOVAS and generalised linear mixed models were used to examine whether mammal index had any impact on the size and the catch or occupancy of invertebrates. Increased rat and mouse tracking was associated with reduced coleoptera catch whilst increased hedgehog tracking was correlated with increases in Coleoptera catch. Pitfall trapped wētā (Hemiandrus spp) showed strong negative responses to increased rat tracking, neutral responses to mice and positive responses to hedgehogs. Tree wētā (Hemideina crassidens) occupancy rates declined in response to increased mouse abundance whilst the mean size of tree wētā residing in wētā motels showed an increase in response to rats and mice. These results show the complexity of understanding mammal invertebrate interactions which cannot be expected to be the same in all environments or across all taxa. Environmental factors typically impact far more strongly on invertebrate populations than they do on vertebrates and can obscure the impacts of top down predation in such studies. The results reported in this study only became apparent after 5+ years of sampling, demonstrating the importance of long-term temporal analysis of invertebrate communities in response to mammals before trends start to emerge. More research is required into the basic ecology and population dynamics of invertebrate communities before more general trends can be discerned.</p>

Mouse plagues in South Australia cereal-growing areas III. Changes in mouse abundance during plague and non-plague years, and the role of refugia

1991 ◽  
Vol 18 (5) ◽  
pp. 593 ◽  
Author(s):  
GJ Mutze
Keyword(s):  
Survival Rates ◽  
South Australia ◽  
Breeding Population ◽  
Early Spring ◽  
Late Spring ◽  
Late Winter ◽  
Population Declines ◽  
Population Changes ◽  
Railway Line ◽  
Large Numbers

Mouse populations were monitored at 15 sites between 1980 and 1990, during which time one severe mouse plague, in 1980, and one minor outbreak, in 1984, were recorded. Smaller annual peaks in autumn to early winter were followed by winter population declines. Crops were colonised each year in late winter or early spring by mice from winter refuge habitats with dense, low vegetation, including roadsides and grassland along a railway line. In most years mouse numbers in crops declined during summer, but in 1983-84 they rose continuously during summer and autumn, and reached very high levels. Crops planted in 1984 were invaded by large numbers of mice which had survived through winter in the paddocks, but population levels again crashed in late spring and summer. Recorded population changes were generally consistent with plague probabilities predicted from environmental variables, except in 1985 when numbers failed to reach the predicted high levels at most sites. Population changes in crops during late spring appear to be critical in the development of mouse plagues. Large litter sizes and pregnancy rates, and variable survival rates and size of the breeding population, appear to be important factors at that time.

scholarly journals The impact of mammalian insectivores Rattus rattus (Rat), Mus musculus (Mouse) & Erinaceus europeus (Hedgehog) on the size and abundance of mainland Coleoptera and Orthoptera

2021 ◽  
Author(s):  
◽  
Thomas Hewitt
Keyword(s):  
Mus Musculus ◽  
Rattus Rattus ◽  
Temporal Analysis ◽  
Invertebrate Communities ◽  
Introduced Predators ◽  
Mammalian Predators ◽  
Study Sites ◽  
Tree Weta ◽  
Occupancy Rates ◽  
The Impact

<p>The impact of introduced mammalian predators on indigenous vertebrates is relatively well documented, however the general responses of indigenous invertebrate communities is less well known. Many indigenous invertebrates, particularly the large flightless species such as those in the genus Deinacrida (Orthoptera) and Anagotus (Curculionidae) have been extirpated from much of their range due largely to the impacts of introduced predators. Despite these well-known examples very little is known about the general impact of introduced predators on invertebrate communities. Beginning in 2012 pitfall traps and artificial wētā motels were established across seven study sites in the Aorangi and Remutaka ranges east of Wellington alternately baited with squid and monitored two to three times annually. Mammal tracking took place in the form of tracking tunnels giving three mammal indexes for rats (Rattus rattus), mice (Mus musculus) and hedgehogs (Erinaceus europeus). Cavity dwelling wētā in wētā motels were measured and counted in situ whilst pitfall trapped Coleoptera and Orthoptera were transported to the lab for measuring and identification. Linear mixed effects model, type 3 ANOVAS and generalised linear mixed models were used to examine whether mammal index had any impact on the size and the catch or occupancy of invertebrates. Increased rat and mouse tracking was associated with reduced coleoptera catch whilst increased hedgehog tracking was correlated with increases in Coleoptera catch. Pitfall trapped wētā (Hemiandrus spp) showed strong negative responses to increased rat tracking, neutral responses to mice and positive responses to hedgehogs. Tree wētā (Hemideina crassidens) occupancy rates declined in response to increased mouse abundance whilst the mean size of tree wētā residing in wētā motels showed an increase in response to rats and mice. These results show the complexity of understanding mammal invertebrate interactions which cannot be expected to be the same in all environments or across all taxa. Environmental factors typically impact far more strongly on invertebrate populations than they do on vertebrates and can obscure the impacts of top down predation in such studies. The results reported in this study only became apparent after 5+ years of sampling, demonstrating the importance of long-term temporal analysis of invertebrate communities in response to mammals before trends start to emerge. More research is required into the basic ecology and population dynamics of invertebrate communities before more general trends can be discerned.</p>

A Study On Impact Of Work Life Related Factors On Employee Engagement In Health Care Sector Workers In Dindigul District.

2019 ◽  
Vol 118 (7) ◽  
pp. 20-26
Author(s):  
S. JAYARAMAN ◽  
R. Sindhya ◽  
P. Vijiyalakshmi
Keyword(s):  
Health Care ◽  
Path Analysis ◽  
Employee Engagement ◽  
Health Care Workers ◽  
Health Care Sector ◽  
Work Life ◽  
Primary Data ◽  
Related Factors ◽  
Care Workers ◽  
The Impact

this research aims to find out the intensity of Employee Engagement of the health care sector workers and the relationship between the Work life factors and Employee Engagement of Health care sector workers in Dindigul District. Primary data were used in this research, were collected from 298 Health care workers from Dindigul District. Questionnaire was the major tool used to gather the primary data from the selected sample respondents. For this purpose, a well structured questionnaire was constructed with the help of professionals and the practiced employees of various health care units in Dindigul District. The health care employees were chosen by simple random sampling method. The investigative measures of regression Path analysis, and simple percentage analysis were utilized to find the impact of work life related factors with the Employee Engagement. The maximum Health care workers were generally satisfied with their jobs. The analytical procedure of path analysis multiple regressions was utilized to determine the predicting strength among Work life factors and the employee engagement. This study provides an another view about the importance of Work life factors and Employee engagement for organizational effectiveness and performance .

Pengaruh Employee Engagement dan Employee Value Proposition terhadap Kinerja

2020 ◽  
Vol 13 (2) ◽  
Author(s):  
Murti Sumarni
Keyword(s):  
Regression Analysis ◽  
Path Analysis ◽  
Employee Engagement ◽  
Reliability And Validity ◽  
Value Proposition ◽  
Validity Test ◽  
Employee Value ◽  
Branch Office ◽  
The Impact ◽  
Research Analysis

The aim of this research was focused to determine the impact of Employee Engagement and Employee Value Proposition to Performance. The reliability and validity test was conducted to 30 respondents and the result showed that all questions item were proven valid and reliable to be used in further research analysis. Populations in this research were the employees of PT. Bank Mega, Tbk. Branch Office Semarang. Questionnaire wasused to collect the data in the amount of 50 respondents. This research used SPSS to analyze and the result of the regression analysis indicated that the Employee Engagement and Employee Value Proposition had a significant effect to Performance. The result of Path Analysis indicated that Employee Value Proposition could be a moderating variable between the impact of Employee Engagement to Performance.

scholarly journals Indicators of Land, Water, Energy and Food (LWEF) Nexus Resource Drivers: A Perspective on Environmental Degradation in the Gidabo Watershed, Southern Ethiopia

2021 ◽  
Vol 18 (10) ◽  
pp. 5181
Author(s):  
Zinabu Wolde ◽  
Wu Wei ◽  
Haile Ketema ◽  
Eshetu Yirsaw ◽  
Habtamu Temesegn
Keyword(s):  
Population Growth ◽  
Path Analysis ◽  
Driving Factors ◽  
Consumption Patterns ◽  
Southern Ethiopia ◽  
Driving Factor ◽  
Path Coefficients ◽  
Resource Degradation ◽  
The Impact ◽  
Land Water

In Ethiopia, land, water, energy and food (LWEF) nexus resources are under pressure due to population growth, urbanization and unplanned consumption. The effect of this pressure has been a widely discussed topic in nexus resource literature. The evidence shows the predominantly negative impact of this; however, the impact of these factors is less explored from a local scale. As a result, securing nexus resources is becoming a serious challenge for the country. This necessitates the identification of the driving factors for the sustainable utilization of scarce LWEF nexus resources. Our study provides a systemic look at the driving factor indicators that induce nexus resource degradation. We use the Analytical Hierarchical Process (AHP) to develop the indicators’ weights, and use a Path Analysis Model (PAM) to quantitatively estimate the effect of the driving factor indicators on the LWEF nexus resources. The results indicate that social (48%), economic (19%), and policy and institutional changes (14%) are the major nexus resource driving factor indicators. The path analysis results indicate that among the social driving factor indicators, population growth and consumption patterns have a significant direct effect on the LWEF nexus, with path coefficients of 0.15 and 0.089, respectively. Similarly, the potential of LWEF nexus resources is also influenced by the institutional and policy change drivers, such as outdated legislation and poor institutional structure, with path coefficients of 0.46 and 0.39, respectively. This implies that population growth and consumption patterns are the leading social drivers, while outdated legislation and poor institutional structures are the institutional and policies change drivers which have a potential impact on LWEF nexus resource degradation. Similarly, other driving factors such as environmental, economic and technological factors also affect nexus resources to varying degrees. The findings of our study show the benefits of managing the identified driving factors for the protection of LWEF nexus resources, which have close links with human health and the environment. In order to alleviate the adverse effects of driving factors, all stakeholders need to show permanent individual and collective commitment. Furthermore, we underline the necessity of applying LWEF nexus approaches to the management of these drivers, and to optimize the environmental and social outcomes.

scholarly journals Snake charming and the exploitation of snakes in Morocco

Oryx ◽  
2016 ◽  
Vol 52 (2) ◽  
pp. 374-381 ◽  
Author(s):  
Juan M. Pleguezuelos ◽  
Mónica Feriche ◽  
José C. Brito ◽  
Soumía Fahd
Keyword(s):  
Reproductive Output ◽  
Surveys And Questionnaires ◽  
Market Price ◽  
Tourism Industry ◽  
Cultural Dimensions ◽  
Population Declines ◽  
Field Surveys ◽  
Focal Species ◽  
The Impact ◽  
Naja Haje

AbstractTraditional activities that potentially threaten biodiversity represent a challenge to conservationists as they try to reconcile the cultural dimensions of such activities. Quantifying the impact of traditional activities on biodiversity is always helpful for decision making in conservation. In the case of snake charming in Morocco, the practice was introduced there 500 years ago by the religious order the Aissawas, and is now an attraction in the country's growing tourism industry. As a consequence wild snake populations may be threatened by overexploitation. The focal species for snake charming, the Egyptian cobra Naja haje, is undergoing both range and population declines. We estimated the level of exploitation of snakes based on field surveys and questionnaires administered to Aissawas during 2003–2014, and compared our results with those of a study conducted 25 years previously. Aissawas use four venomous and four non-venomous species for snake charming and we estimate they harvest a minimum of 4,500 individuals annually, mostly venomous snakes. For exhibition purposes they selectively remove the largest specimens from the wild (i.e. those that could have the highest reproductive output). Compared to the previous data, we detected (1) a reduction in the number of species collected, (2) an increased distance to collecting fields, and (3) an increase in the market price for snakes, after correction for accumulated inflation, signifying a higher demand for these animals.

scholarly journals DAMPAK BPNT TERHADAP KONSUMSI RUMAH TANGGA DAN POLA KONSUMSI RUMAH TANGGA PENERIMA BPNT, KECAMATAN MENGWI

2021 ◽  
pp. 839
Author(s):  
Luh Ade Yumita Handriani ◽  
Sudarsana Arka
Keyword(s):  
Path Analysis ◽  
Sample Size ◽  
Direct Effect ◽  
Indirect Effect ◽  
Household Consumption ◽  
Consumption Patterns ◽  
Consumption Pattern ◽  
Large Sample Size ◽  
Analysis Techniques ◽  
The Impact

This study aims to analyze the impact of the BPNT program on household consumption and consumption patterns of BPNT recipient households in Mengwi District, Badung Regency. This research was conducted in Mengwi District, Badung Regency using a questionnaire distributed to respondents with a large sample size of 96 KPM. This study uses path analysis techniques to analyze the direct effect and Sobel test to analyze the indirect effect. Based on path analysis, the results of the study concluded that the BPNT variable had a positive and significant effect on the consumption of BPNT recipient households in Mengwi District, Badung Regency. The BPNT variable has no effect on the consumption pattern of BPNT recipient households in Mengwi District, Badung Regency. The household consumption variable has a negative and significant effect on the consumption pattern of BPNT recipient households in Mengwi District, Badung Regency. The household consumption variable did mediate the effect of the BPNT Program on the consumption pattern of BPNT recipient households in Mengwi District, Badung Regency

Sign in / Sign up

Export Citation Format

Share Document