Density estimates of cane toads from native populations based on mark-recapture data

1996 ◽  
Vol 23 (3) ◽  
pp. 305 ◽  
Author(s):  
M Lampo ◽  
P Bayliss
Keyword(s):  
Air Temperature ◽  
Native Species ◽  
Population Estimates ◽  
Cane Toad ◽  
Potential Threat ◽  
Density Estimates ◽  
Mark Recapture ◽  
Climate Conditions ◽  
Wide Range ◽  
Native Populations

The cane toad (Bufo marinus) has received considerable attention because of its rapid spread in Australia and the potential threat it may represent to native species. Although the introduction of pathogens from native populations is now being considered to control this species, population estimates based on comparable methods that demonstrate that native populations are in fact less dense than the introduced ones are not available. Accurate population estimates are necessary to evaluate potential techniques for the control of the cane toad. We estimated population densities of cane toads over a wide range of habitat types and climate conditions by means of mark-recapture data. The capture history and location of toads each night were analysed to explore the validity of some of the assumptions of mark-recapture models. Because migrations, deaths and recruitment over three nights appear to be unimportant, populations may be legitimately regarded as closed for that period. However, cane toads seem highly sensitive to disturbance effects due to trapping andlor handling. Consequently, density estimates based on removal methods seem the most reliable because they are not sensitive to handling and trapping effects. Similarly, analyses of residuals of regressions between 1-night counts and density estimates suggested that toad nightly activity is affected by the air temperature during sampling. However, only 60% of the variation in estimated densities can be predicted by 1-night counts and air temperature. Estimates of population density over a wide range of habitats in South America were one order of magnitude lower than estimates in Australia. We speculate on the possible factors that may account for the lower densities in populations in the native range of the species.

scholarly journals The impacts of an introduced mammalian predator (Mus musculus) on tree weta (Hemideina trewicki) and skinks (Oligosoma polychroma, Oligosoma infrapunctatum and Oligosoma lineoocellatum) in Cape Sanctuary, Hawkes Bay

2021 ◽  
Author(s):  
◽  
Emma Dent
Keyword(s):  
Native Species ◽  
Conservation Management ◽  
Limiting Factor ◽  
Pitfall Traps ◽  
Mark Recapture ◽  
Introduced Predators ◽  
Native Populations ◽  
Mammalian Predator ◽  
Tree Weta ◽  
The Impact

<p>The introduction of exotic species, particularly predators, into new ecosystems is one of the biggest causes of loss of biodiversity across the globe. Understanding the impacts that introduced species have on native species is crucial in conservation management, particularly for those species that are conservation-reliant. I examined the impact that an introduced mammalian predator (Mus muscularus) had on native prey populations of common (Oligosoma polychroma), speckled (Oligosoma infrapunctatum) and spotted (Oligosoma lineoocellatum) skinks and Hawkes Bay tree weta (Hemideina trewicki). I conducted a mark-recapture study using pitfall traps to examine the impact of mice on skink populations. I conducted a mark-recapture study through manual counts to examine the impact of mice on tree weta. I also examined occupancy of weta refuges while in the presence of mice. There were no captures of spotted skinks, and very low captures of common skinks. There was no significant change in capture numbers for speckled skink, however observed numbers did decline from November 2013 to November 2014. There was a significant decline in capture rates for tree weta over the course of my study. It was difficult to establish mice as the sole cause of any observed changes, however it is likely that they are a limiting factor for skink and weta populations, and have the potential to be a major factor in the observed decline in the tree weta population. My results highlight the importance of monitoring native populations, particularly those that are small and are in the presence of introduced predators. By monitoring native populations conservation management can make better informed decisions to work towards populations not being ‘conservation-reliant’.</p>

scholarly journals The impacts of an introduced mammalian predator (Mus musculus) on tree weta (Hemideina trewicki) and skinks (Oligosoma polychroma, Oligosoma infrapunctatum and Oligosoma lineoocellatum) in Cape Sanctuary, Hawkes Bay

2021 ◽  
Author(s):  
◽  
Emma Dent
Keyword(s):  
Native Species ◽  
Conservation Management ◽  
Limiting Factor ◽  
Pitfall Traps ◽  
Mark Recapture ◽  
Introduced Predators ◽  
Native Populations ◽  
Mammalian Predator ◽  
Tree Weta ◽  
The Impact

<p>The introduction of exotic species, particularly predators, into new ecosystems is one of the biggest causes of loss of biodiversity across the globe. Understanding the impacts that introduced species have on native species is crucial in conservation management, particularly for those species that are conservation-reliant. I examined the impact that an introduced mammalian predator (Mus muscularus) had on native prey populations of common (Oligosoma polychroma), speckled (Oligosoma infrapunctatum) and spotted (Oligosoma lineoocellatum) skinks and Hawkes Bay tree weta (Hemideina trewicki). I conducted a mark-recapture study using pitfall traps to examine the impact of mice on skink populations. I conducted a mark-recapture study through manual counts to examine the impact of mice on tree weta. I also examined occupancy of weta refuges while in the presence of mice. There were no captures of spotted skinks, and very low captures of common skinks. There was no significant change in capture numbers for speckled skink, however observed numbers did decline from November 2013 to November 2014. There was a significant decline in capture rates for tree weta over the course of my study. It was difficult to establish mice as the sole cause of any observed changes, however it is likely that they are a limiting factor for skink and weta populations, and have the potential to be a major factor in the observed decline in the tree weta population. My results highlight the importance of monitoring native populations, particularly those that are small and are in the presence of introduced predators. By monitoring native populations conservation management can make better informed decisions to work towards populations not being ‘conservation-reliant’.</p>

Effects of Air Temperature on Combustion Characteristics of LPG Diffusion Flame

2020 ◽  
Vol 1008 ◽  
pp. 128-138
Author(s):  
Ahmed M. Salman ◽  
Ibrahim A. Ibrahim ◽  
Hamada M. Gad ◽  
Tharwat M. Farag
Keyword(s):  
Air Temperature ◽  
Diffusion Flame ◽  
Nitrogen Addition ◽  
Flame Length ◽  
Combustion Characteristics ◽  
Operating Conditions ◽  
Low Oxygen ◽  
Air Temperatures ◽  
Air Stream ◽  
Wide Range

In the present study, the combustion characteristics of LPG gaseous fuel diffusion flame at elevated air temperatures were experimentally investigated. An experimental test rig was manufactured to examine a wide range of operating conditions. The investigated parameters are the air temperatures of 300, 350, 400, 450, and 500 K with constant percentage of nitrogen addition in combustion air stream of 5 % to give low oxygen concentration of 18.3 % by mass at constant air swirl number, air to fuel mass ratio, and thermal load of 1.5, 30, and 23 kW, respectively. The gaseous combustion characteristics were represented as axial and radial temperatures distributions, temperatures gradient, visible flame length and species concentrations. The results indicated that as the air temperature increased, the chemical reaction rate increased and flame volume decreased, the combustion time reduced leading to a reduction in flame length. The NO concentration reaches its maximum values near the location of the maximum centerline axial temperature. Increasing the combustion air temperature by 200 K, the NO consequently O2 concentrations are increased by about % 355 and 20 % respectively, while CO2 and CO concentrations are decreased by about % 21 and 99 % respectively, at the combustor end.

scholarly journals Transferability Intercomparison: An Opportunity for New Insight on the Global Water Cycle and Energy Budget

2007 ◽  
Vol 88 (3) ◽  
pp. 375-384 ◽  
Author(s):  
E. S. Takle ◽  
J. Roads ◽  
B. Rockel ◽  
W. J. Gutowski ◽  
R. W. Arritt ◽  
...  
Keyword(s):  
Energy Budget ◽  
Climate Models ◽  
Climate Model ◽  
Water Cycle ◽  
Regional Climate ◽  
Climate Conditions ◽  
Continental Scale ◽  
Global Water Cycle ◽  
Wide Range ◽  
Global Water

A new approach, called transferability intercomparisons, is described for advancing both understanding and modeling of the global water cycle and energy budget. Under this approach, individual regional climate models perform simulations with all modeling parameters and parameterizations held constant over a specific period on several prescribed domains representing different climatic regions. The transferability framework goes beyond previous regional climate model intercomparisons to provide a global method for testing and improving model parameterizations by constraining the simulations within analyzed boundaries for several domains. Transferability intercomparisons expose the limits of our current regional modeling capacity by examining model accuracy on a wide range of climate conditions and realizations. Intercomparison of these individual model experiments provides a means for evaluating strengths and weaknesses of models outside their “home domains” (domain of development and testing). Reference sites that are conducting coordinated measurements under the continental-scale experiments under the Global Energy and Water Cycle Experiment (GEWEX) Hydrometeorology Panel provide data for evaluation of model abilities to simulate specific features of the water and energy cycles. A systematic intercomparison across models and domains more clearly exposes collective biases in the modeling process. By isolating particular regions and processes, regional model transferability intercomparisons can more effectively explore the spatial and temporal heterogeneity of predictability. A general improvement of model ability to simulate diverse climates will provide more confidence that models used for future climate scenarios might be able to simulate conditions on a particular domain that are beyond the range of previously observed climates.

Galapagos Tortoises and Sea Turtles in Gold Rush-Era California

2014 ◽  
Vol 91 (2) ◽  
pp. 20-39 ◽  
Author(s):  
Cyler Conrad ◽  
Allen Pastron
Keyword(s):  
San Francisco ◽  
Native Species ◽  
Sea Turtles ◽  
Rare Event ◽  
Legal Protection ◽  
Sea Turtle ◽  
Gold Rush ◽  
Late Nineteenth Century ◽  
Scientific Curiosity ◽  
Native Populations

Spotting a sea turtle or Galapagos tortoise on the early wharfs and streets of San Francisco or Sacramento, California during the Gold Rush (1848-1855) would not have been a rare event. Massive population influx into the San Francisco Bay region during this time resulted in substantial impacts to native species and habitats of all taxa, but the demand for food resulted in many resources, turtles and tortoises included, being imported into the cities. Providing a fresh and delectable food source, these terrapin were brought to San Francisco and Sacramento to feed the hungry Gold Rush populous. Their taste, popularity and demand also resulted in small numbers being imported into gold mining towns in the San Joaquin Valley and foothills of the Sierra Nevada’s. Remarkable as this process was, the consumption and importation of both sea turtles and Galapagos tortoises during the Gold Rush pushed native populations of these species to the brink of extinction during the mid to late-nineteenth century. Declining numbers of terrapin and increased scientific curiosity, with a desire to safeguard these creatures for future generations, resulted in their eventually legal protection and conservation. In many ways the impacts of the decimation of terrapin in the eastern Pacific during the Gold Rush are still felt today, as conservation and breeding efforts continue in an attempt to return native turtle and tortoise populations to pre-Euro-American contact levels. This research describes the historical, and new archaeofaunal, evidence of the terrapin import market in San Francisco, Sacramento and beyond during the dynamic period of the California Gold Rush.

scholarly journals North American channel catfish, Ictalurus punctatus: a neglected but potentially invasive freshwater fish species?

2021 ◽  
Vol 23 (5) ◽  
pp. 1563-1576 ◽  
Author(s):  
Phillip J. Haubrock ◽  
Gordon H. Copp ◽  
Iva Johović ◽  
Paride Balzani ◽  
Alberto F. Inghilesi ◽  
...  
Keyword(s):  
North America ◽  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
North American ◽  
Disease Transmission ◽  
Native Species ◽  
Assessment Protocol ◽  
South Italy ◽  
Wide Range ◽  
North And South

AbstractThe North American channel catfish Ictalurus punctatus has been introduced to several locations in Europe but has received little or no scientific study despite its invasive attributes, including prolific reproduction, tolerance to a wide range of conditions, opportunistic feeding, at least partial ‘predator release’, and some evidence of environmental impacts (e.g. disease transmission). To assess the species’ potential invasiveness and the likely risks to native species and ecosystems in Europe, available literature from both North America and Europe was reviewed and used to carry out risk screenings of the species for the risk assessment areas, North and South Italy, using the Aquatic Invasiveness Screening Kit (AS-ISK), which was followed by a more detailed evaluation (for both North America and Europe) of the species’ potential impacts using the Environmental Impact Classification of Alien Taxa (EICAT) assessment protocol. The AS-ISK score indicated that channel catfish is likely to pose a high risk of being invasive in both North and South Italy, with EICAT scores indicating “Major” impacts for both North America and Europe, at high and medium confidence levels, respectively. The present results emphasise the urgent need to carry out in-depth studies on introduced populations of this species to understand better its invasive potential so as to inform management decisions on the appropriate control or eradication measures for invaded water bodies.

scholarly journals Onorchard habitats for Nysius huttoni an important kiwifruit passenger pest

2014 ◽  
Vol 67 ◽  
pp. 326-326
Author(s):  
C.A. Rowe ◽  
M.G. Hill ◽  
D.P. Logan
Keyword(s):  
Native Species ◽  
Host Plants ◽  
Ground Vegetation ◽  
Preliminary Survey ◽  
Weed Species ◽  
Quarantine Pest ◽  
Polygonum Aviculare ◽  
Brassica Crops ◽  
Wide Range ◽  
High Incidence

Nysius huttoni is a native species of wheat bug which is an occasional quarantine pest on export kiwifruit Wheat bug has a wide range of host plants including wheat and brassica crops as well as many weed species The kiwifruit harvest of 2013 had a high incidence of wheat bug finds on fruit in packhouses In response an orchard survey was undertaken to identify orchard habitats used by wheat bug Twentyfive orchards where wheat bug was found during packing in 2013 were surveyed from the Te Puke area from February to March At each orchard four habitats were searched (1) ground vegetation under the kiwifruit canopy (2) the loadout zone (3) edge of the loadout zone and (4) grassland surrounding the was found in and around the loadout zone associated with weed species notably Polygonum aviculare the dominant weed species in loadout zones No wheat bug was found under the kiwifruit canopy and the remaining 4 were found in grassland This preliminary survey suggests that the risk of wheat bug infestation can be reduced considerably by keeping loadout zones free of weeds during spring and summer

scholarly journals Does the punishment fit the crime? Consequences and diagnosis of misspecified detection functions in Bayesian spatial capture-recapture modelling

2021 ◽  
Author(s):  
Soumen Dey ◽  
Richard Bischof ◽  
Pierre P. A. Dupont ◽  
Cyril Milleret
Keyword(s):  
Home Range ◽  
Space Use ◽  
Relative Bias ◽  
Diagnostic Tools ◽  
List Type ◽  
Detection Function ◽  
Density Estimates ◽  
Use Patterns ◽  
Wide Range ◽  
Capture Recapture

AbstractSpatial capture-recapture (SCR) is now used widely to estimate wildlife densities. At the core of SCR models lies the detection function, linking individual detection probability to the distance from its latent activity center. The most common function (half-normal) assumes a bivariate normal space use and consequently detection pattern. This is likely an oversimplification and misrepresentation of real-life animal space use patterns, but studies have reported that density estimates are relatively robust to misspecified detection functions. However, information about consequences of such misspecification on space use parameters (e.g. home range area), as well as diagnostic tools to reveal it are lacking.We simulated SCR data under six different detection functions, including the half-normal, to represent a wide range of space use patterns. We then fit three different SCR models, with the three simplest detection functions (half-normal, exponential and half-normal plateau) to each simulated data set. We evaluated the consequences of misspecification in terms of bias, precision and coverage probability of density and home range area estimates. We also calculated Bayesian p-values with respect to different discrepancy metrics to assess whether these can help identify misspecifications of the detection function.We corroborate previous findings that density estimates are robust to misspecifications of the detection function. However, estimates of home range area are prone to bias when the detection function is misspecified. When fitted with the half-normal model, average relative bias of 95% kernel home range area estimates ranged between −25% and 26% depending on the misspecification. In contrast, the half-normal plateau model (an extension of the half-normal) returned average relative bias that ranged between −26% and −4%. Additionally, we found useful heuristic patterns in Bayesian p-values to diagnose the misspecification in detection function.Our analytical framework and diagnostic tools may help users select a detection function when analyzing empirical data, especially when space use parameters (such as home range area) are of interest. We urge development of additional custom goodness of fit diagnostics for Bayesian SCR models to help practitioners identify a wider range of model misspecifications.

scholarly journals Current Trends in the Development of Public Administration in the Security Field: National and Global Aspects

2020 ◽  
Vol 47 (4) ◽  
pp. 13-22
Author(s):  
Anatolii KALIAIEV
Keyword(s):  
Public Administration ◽  
Historical Memory ◽  
National Level ◽  
Political Life ◽  
Potential Threat ◽  
Active Involvement ◽  
Current Trends ◽  
Wide Range ◽  
Military Conflicts ◽  
European Values

Current trends in public administration are considered in the context of national security imperatives, in particular regarding prevention and elimination of military conflicts, achievement of international understanding and formation of a global security environment. In recent decades, military conflicts of varying intensity and scale, both in Europe and beyond the continent, have remained a potential threat to Ukraine and all European countries. The research methodology is based on a systematic approach, which, in particular, summarizes modern interpretations of public administration and identifies problematic aspects of reforming modern governance structures amid globalization, informatization and democratization of the society and government. The position on the effectiveness and political perspective of democratic reforms is substantiated. Similar processes are observed in public administration in the security field within the democratic trend aimed at developing a dialogue between society and government through the active involvement of a wide range of non-state actors. On the basis of the dialectical method the trends of public administration development in the field of military security are researched and their ambivalence is argued. The global context of the new consolidated view on the protection of the common future of humanity is noted. The axiological method has provided an opportunity to characterize the processes of securitization of socio-political life and to determine the prospects for reducing its conflictogenity. It is consistently held that the most effective and efficient is the combination of three levels of identity in integrated European societies: maintaining strong positions of the customary national level of self-identification, transnational level of common European values and ethnic level of identity - preservation of historical memory.

scholarly journals Predicting Current Potential Distribution and the Range Dynamics of Pomacea canaliculata in China under Global Climate Change

Biology ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 110
Author(s):  
Yingxuan Yin ◽  
Qing He ◽  
Xiaowen Pan ◽  
Qiyong Liu ◽  
Yinjuan Wu ◽  
...  
Keyword(s):  
Climate Change ◽  
Native Species ◽  
Potential Distribution ◽  
Global Climate ◽  
Social Economy ◽  
Maximum Temperature ◽  
Pomacea Canaliculata ◽  
Climate Conditions ◽  
Jackknife Test ◽  
Recent Climate

Pomacea canaliculata is one of the 100 worst invasive alien species in the world, which has significant effects and harm to native species, ecological environment, human health, and social economy. Climate change is one of the major causes of species range shifts. With recent climate change, the distribution of P. canaliculata has shifted northward. Understanding the potential distribution under current and future climate conditions will aid in the management of the risk of its invasion and spread. Here, we used species distribution modeling (SDM) methods to predict the potential distribution of P. canaliculata in China, and the jackknife test was used to assess the importance of environmental variables for modeling. Our study found that precipitation of the warmest quarter and maximum temperature in the coldest months played important roles in the distribution of P. canaliculata. With global warming, there will be a trend of expansion and northward movement in the future. This study could provide recommendations for the management and prevention of snail invasion and expansion.

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