scholarly journals Are invasive populations characterized by a broader diet than native populations?

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3250 ◽  
Author(s):  
Julien Courant ◽  
Solveig Vogt ◽  
Raquel Marques ◽  
John Measey ◽  
Jean Secondi ◽  
...  
Keyword(s):  
Invasive Species ◽  
Xenopus Laevis ◽  
Selection Index ◽  
Trophic Relationships ◽  
Generalist Predator ◽  
Ecological Traits ◽  
Prey Category ◽  
Animal Populations ◽  
Wide Range ◽  
Native Populations

Background Invasive species are among the most significant threats to biodiversity. The diet of invasive animal populations is a crucial factor that must be considered in the context of biological invasions. A broad dietary spectrum is a frequently cited characteristic of invasive species, allowing them to thrive in a wide range of environments. Therefore, empirical studies comparing diet in invasive and native populations are necessary to understand dietary requirements, dietary flexibility, and the associated impacts of invasive species. Methods In this study, we compared the diet of populations of the African clawed frog, Xenopus laevis in its native range, with several areas where it has become invasive. Each prey category detected in stomach contents was assigned to an ecological category, allowing a comparison of the diversity of ecological traits among the prey items in the diet of native and introduced populations. The comparison of diets was also performed using evenness as a niche breadth index on all sampled populations, and electivity as a prey selection index for three out of the six sampled populations. Results Our results showed that diet breadth could be either narrow or broad in invasive populations. According to diet and prey availability, zooplankton was strongly preferred in most cases. In lotic environments, zooplankton was replaced by benthic preys, such as ephemeropteran larvae. Discussion The relative proportions of prey with different ecological traits, and dietary variability within and between areas of occurrence, suggest that X. laevis is a generalist predator in both native and invasive populations. Shifts in the realized trophic niche are observed, and appear related to resource availability. Xenopus laevis may strongly impact aquatic ecosystems because of its near complete aquatic lifestyle and its significant consumption of key taxa for the trophic relationships in ponds.

The Biology of Mediterranean-Type Ecosystems

2018 ◽  
Author(s):  
Karen J. Esler ◽  
Anna L. Jacobsen ◽  
R. Brandon Pratt
Keyword(s):  
Climate Change ◽  
South Africa ◽  
Invasive Species ◽  
Habitat Loss ◽  
Endemic Species ◽  
Geographic Area ◽  
Cutting Edge ◽  
Wide Range ◽  
The Mediterranean ◽  
Mediterranean Type Ecosystems

The world’s mediterranean-type climate regions (including areas within the Mediterranean, South Africa, Australia, California, and Chile) have long been of interest to biologists by virtue of their extraordinary biodiversity and the appearance of evolutionary convergence between these disparate regions. Comparisons between mediterranean-type climate regions have provided important insights into questions at the cutting edge of ecological, ecophysiological and evolutionary research. These regions, dominated by evergreen shrubland communities, contain many rare and endemic species. Their mild climate makes them appealing places to live and visit and this has resulted in numerous threats to the species and communities that occupy them. Threats include a wide range of factors such as habitat loss due to development and agriculture, disturbance, invasive species, and climate change. As a result, they continue to attract far more attention than their limited geographic area might suggest. This book provides a concise but comprehensive introduction to mediterranean-type ecosystems. As with other books in the Biology of Habitats Series, the emphasis in this book is on the organisms that dominate these regions although their management, conservation, and restoration are also considered.

scholarly journals Effects of Temperature on Anoplophora chinensis (Coleoptera: Cerambycidae) Adult Survival, Reproduction, and Egg Hatch

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 432 ◽  
Author(s):  
Melody A. Keena ◽  
Paul M. Moore ◽  
Gregg Bradford
Keyword(s):  
Invasive Species ◽  
Tree Species ◽  
Adult Survival ◽  
Optimum Temperature ◽  
Egg Hatch ◽  
Laboratory Conditions ◽  
Wide Range ◽  
Survival And Reproduction ◽  
Summer Temperatures ◽  
Effects Of Temperature

Anoplophora chinensis (Forster) is an invasive species that can damage many tree species in orchard, urban, and forested habitats. Adult survival, reproduction, and egg hatch of A. chinensis from Italy and China are evaluated at eight constant temperatures (5, 10, 15, 20, 25, 30, 35, and 40 °C) under laboratory conditions. The estimated Tmax for longevity was 42 and 33 °C for females and 42 and 39 °C for males from China and Italy, respectively. The estimated Tmax, Tmin, and optimum temperature for fecundity were 35, 9, and 29 °C, respectively. Females laid eggs at 15–30 °C and eggs hatched at 15–35 °C. Days to first oviposition increased exponentially from 13 days at 30 °C to >300 days near 10 °C. The estimated Tmin for egg hatch was 13 °C, the Tmax at 38 °C, and the optimum 29 °C. Percentage hatch was estimated to be highest at 26 °C and have a Tmax of 31 °C and Tmin of 10 °C. These results indicate that summer temperatures over a wide range of latitudes should support beetle survival and reproduction, but at temperatures ≥35 °C, oviposition ceases, and adult survivorship declines. In addition, females may survive into the fall, but lay fewer eggs that may not hatch. These responses of A. chinensis to temperature can be used for developing phenological models to predict the timing of stages for management or eradication efforts.

The Mode of Excretion of Ammonia and Urea in Xenopus Laevis

1961 ◽  
Vol 38 (4) ◽  
pp. 695-705
Author(s):  
J. B. BALINSKY ◽  
E. BALDWIN
Keyword(s):  
Xenopus Laevis ◽  
Blood Concentration ◽  
Concentration Ratio ◽  
Ammonia Excretion ◽  
Ammonia Concentration ◽  
Mean Value ◽  
Urea Excretion ◽  
Wide Range ◽  
Glomerular Filtrate ◽  
The Mean

1. Eighty-two single determinations of ammonia and urea excretion by Xenopus laevis indicated that the percentage of ammonia varied from 40 to 80%, with a mean value of 62%. 2. Measurements of excretion on successive days after feeding showed that a large amount of ammonia was produced soon after feeding, but that ammonia excretion declined rapidly. Urea excretion, not so high initially, remained more or less constant until the third or fourth day, often exceeding ammonia excretion at that time. Thereafter, it also declined and the excretion of both substances reached a constant starvation level by the fifteenth day. 3. Both ammonia and urea excretion were equally affected by temperature. The Q10's were near 2 in the range 20-30° C., but greater in the range 10-20° C. 4. At least 86% of ammonia, and 81% of urea were excreted through the cloaca. 5. The mean 24 hr. urine output of Xenopus at 20% C. was 23.6 ml. per 100 g. body weight. 6. Although the blood ammonia concentration did not appear to be zero, the urine/blood concentration ratio of ammonia was greater than 100. The urine/blood concentration ratio of urea was not significantly different from unity, and constant over a very wide range of concentrations. 7. The above result is interpreted to indicate passive glomerular filtration of urea, and little or no tubular reabsorption of water. 8. It is suggested that ammonia is formed in the kidney, and actively secreted into the glomerular filtrate.

scholarly journals Use of environmental DNA (eDNA) in streams to detect feral swine (Sus scrofa)

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8287
Author(s):  
Amberly N. Hauger ◽  
Karmen M. Hollis-Etter ◽  
Dwayne R. Etter ◽  
Gary J. Roloff ◽  
Andrew R. Mahon
Keyword(s):  
Invasive Species ◽  
Water Temperature ◽  
Linear Model ◽  
Detection Probability ◽  
Generalized Linear Model ◽  
Environmental Dna ◽  
The United States ◽  
Stream Data ◽  
Feral Swine ◽  
Animal Populations

Invasive feral swine can damage ecosystems, disrupt plant and animal populations, and transmit diseases. Monitoring of feral swine populations requires expensive and labor-intensive techniques such as aerial surveys, field surveys for sign, trail cameras, and verifying landowner reports. Environmental DNA (eDNA) provides an alternative method for locating feral swine. To aid in detection of this harmful invasive species, a novel assay was developed incorporating molecular methods. From August 2017 to April 2018, water samples and stream data were collected along 400 m transects in two different stream types where swine DNA was artificially introduced to investigate potential factors affecting detection. A generalized linear model (family binomial) was used to characterize environmental conditions affecting swine DNA detection; detection was the dependent variable and stream measurements included stream type, distance downstream, water temperature, velocity, turbidity, discharge, and pH as independent variables. Parameters from the generalized linear model were deemed significant if 95% confidence intervals did not overlap 0. Detection probability for swine DNA negatively related to water temperature (β =  − 0.21, 95% CI [−0.35 to −0.09]), with the highest detection probability (0.80) at 0 °C and lowest detection probability (0.05) at 17.9 °C water temperature. Results indicate that sampling for swine eDNA in free-flowing stream systems should occur at lower water temperatures to maximize detection probability. This study provides a foundation for further development of field and sampling techniques for utilizing eDNA as a viable alternative to monitoring a terrestrial invasive species in northern regions of the United States.

scholarly journals Climate structuring of Batrachochytrium dendrobatidis infection in the threatened amphibians of the northern Western Ghats, India

2018 ◽  
Vol 5 (6) ◽  
pp. 180211 ◽  
Author(s):  
Christopher J. Thorpe ◽  
Todd R. Lewis ◽  
Matthew C. Fisher ◽  
Claudia J. Wierzbicki ◽  
Siddharth Kulkarni ◽  
...  
Keyword(s):  
Western Ghats ◽  
Batrachochytrium Dendrobatidis ◽  
Coastal Region ◽  
First Record ◽  
Climatic Conditions ◽  
Ecological Traits ◽  
Temperature Changes ◽  
Reverse Pattern ◽  
Wide Range ◽  
The Western Ghats

Batrachochytrium dendrobatidis ( Bd ) is a pathogen killing amphibians worldwide. Its impact across much of Asia is poorly characterized. This study systematically surveyed amphibians for Bd across rocky plateaus in the northern section of the Western Ghats biodiversity hotspot, India, including the first surveys of the plateaus in the coastal region. These ecosystems offer an epidemiological model system since they are characterized by differing levels of connectivity, edaphic and climatic conditions, and anthropogenic stressors. One hundred and eighteen individuals of 21 species of Anura and Apoda on 13 plateaus ranging from 67 to 1179 m above sea level and 15.89 to 17.92° North latitude were sampled. Using qPCR protocols, 79% of species and 27% of individuals tested were positive for Bd . This is the first record of Bd in caecilians in India, the Critically Endangered Xanthophryne tigerina and Endangered Fejervarya cf. sahyadris . Mean site prevalence was 28.15%. Prevalence below the escarpment was 31.2% and 25.4% above. The intensity of infection (GE) showed the reverse pattern. Infection may be related to elevational temperature changes, thermal exclusion, inter-site connectivity and anthropogenic disturbance. Coastal plateaus may be thermal refuges from Bd . Infected amphibians represented a wide range of ecological traits posing interesting questions about transmission routes.

scholarly journals Eastern Coyotes (Canis latrans var.) consuming large ungulates in a multi-ungulate system

2020 ◽  
Vol 134 (1) ◽  
pp. 45-51
Author(s):  
Juliana Balluffi-Fry ◽  
Liane B. Nowell ◽  
Murray M. Humphries
Keyword(s):  
Prey Species ◽  
Canis Latrans ◽  
Feeding Habits ◽  
Castor Canadensis ◽  
Generalist Predators ◽  
Generalist Predator ◽  
Wide Range ◽  
Game Reserve ◽  
Varied Diet ◽  
American Beaver

The feeding habits of generalist predators often vary among populations and regions. For example, Coyote (Canis latrans), which is a generalist predator distributed across North America, occupies a wide range of habitats and has a highly varied diet. In this observational study, we quantified the presence of mammalian prey items in 50 Eastern Coyote (Canis latrans var.) scats collected in late spring and summer in a private game reserve in southwestern Quebec. Nearly all scats contained hair of White-tailed Deer (Odocoileus virginianus; 44%), Moose (Alces americanus; 38%), or American Beaver (Castor canadensis; 38%). Although all three species are known to be consumed by coyotes, such a high proportion of Moose and White-tailed Deer simultaneously occurring in the diet of coyotes has not been previously reported. The uniqueness of the study area, with its relatively high abundance of all three prey species, may account for the uniqueness of the diet of Eastern Coyotes living there.

scholarly journals Signals and Spite in Fluctuating Populations

2019 ◽  
Vol 2 (1) ◽  
pp. 137-146
Author(s):  
Rory Smead ◽  
Patrick Forber
Keyword(s):  
Recent Work ◽  
Computational Methods ◽  
Social Behaviors ◽  
Small Populations ◽  
Stochastic Effects ◽  
Animal Populations ◽  
Wide Range ◽  
Fluctuating Populations

AbstractSpite (in the biological or evolutionary sense) is behavior that harms others at a cost to the actor. The presence of spite in human and animal populations presents an evolutionary puzzle. Recent work has suggested small populations and pre-play signaling can have a significant effect on the evolution of spite. Here, we use computational methods to explore these factors in fluctuating populations that may go extinct. We find that the presence of spite can make a population significantly more likely to go extinct, but that this does not preclude the possibility of spite reliably evolving. Additionally, we find that the stochastic effects of small fluctuating populations allow for the evolution and predominance of signal-mediated conditional spite across a wide range of conditions. These results suggest that directed harm, even if costly, can play a significant early role in the evolution of social behaviors and this provides a possible origin for punishment.

scholarly journals Rapid climate-driven evolution of the invasive species Mytilus galloprovincialis over the past century

2020 ◽  
Vol 3 (1) ◽  
pp. 14-29
Author(s):  
Guo-Dong Han ◽  
Yun-Wei Dong
Keyword(s):  
Invasive Species ◽  
Genetic Variation ◽  
Mytilus Galloprovincialis ◽  
Climatic Factors ◽  
Northwestern Pacific ◽  
Past Century ◽  
Nucleotide Polymorphisms ◽  
Adaptive Genetic Variation ◽  
The Past ◽  
Wide Range

Climate-driven adaptive genetic variation is one of the most important ways for organisms to tolerate environmental change and succeed in altered environments. To understand rapid climate-driven evolution, and how this evolution might shift biogeographic distributions in response to global change, we measured the adaptive genetic variation to the local environment of a marine invasive species Mytilus galloprovincialis. The genetic structure of eight populations from the Mediterranean Sea, northeastern Atlantic, northeastern Pacific, and northwestern Pacific were determined using genome-wide screens for single nucleotide polymorphisms. The relationships of genetic variation to environmental (seawater and air) temperature were analyzed using redundancy analysis and BayeScEnv analysis to evaluate the impacts of temperature on the genetic divergences among these eight populations. We found that the genetic compositions were significantly different among populations and the adaptive genetic variation was associated with temperature variables. Further, we identified some genetic markers exhibiting signatures of divergent selection in association with environmental features that can be used in the future to closely monitor adaptive variation in this species. Our results suggest that divergent climatic factors have driven adaptive genetic variation in M. galloprovincialis over the past century. The rapid evolutionary adaptation has played a pivotal role in enabling this species to invade a wide range of thermal habitats successfully. Species like M. galloprovincialis that possess high levels of genetic variation may not only be especially capable of invading new habitats with different environmental conditions, but also poised to cope rapidly and successfully with rising global temperatures.

Detection of a global aquatic invasive amphibian, Xenopus laevis, using environmental DNA

2016 ◽  
Vol 37 (1) ◽  
pp. 131-136 ◽  
Author(s):  
Jean Secondi ◽  
Tony Dejean ◽  
Alice Valentini ◽  
Benjamin Audebaud ◽  
Claude Miaud
Keyword(s):  
Invasive Species ◽  
Xenopus Laevis ◽  
Dna Amplification ◽  
Control Program ◽  
Environmental Dna ◽  
Climatic Conditions ◽  
Low Density ◽  
African Species ◽  
A Site ◽  
And Control

Detection is crucial in the study and control of invasive species but it may be limited by methodological issues. In amphibians, classical survey techniques exhibit variable detection probability depending on species and are often constrained by climatic conditions often requiring several site visits. Furthermore, detection may be reduced at low density because probability capture (passive traps), or activity (acoustic surveys) drop. Such limits may impair the study of invasive species because low density is typical of the onset of colonisation on a site. In the last few years, environmental DNA (eDNA) methods have proved their ability to detect the presence of aquatic species. We developed here an eDNA method to detectXenopus laevisin ponds. This austral African species is now present worldwide because of its use in biology and as a pet. Populations have settled and expanded on several continents so that it is now considered as one of the major invasive amphibians in the World. We detected the presence ofX. laevisat density as low as 1 ind/100 m2and found a positive relationship between density in ponds and rate of DNA amplification. Results show that eDNA can be successfully applied to survey invasive populations ofX. laeviseven at low density in order to confirm suspected cases of introduction, delimit the expansion of a colonized range, or monitor the efficiency of a control program.

Present and Future Use of Fencing in the Management of Larger African Mammals

1992 ◽  
Vol 19 (2) ◽  
pp. 160-164 ◽  
Author(s):  
Richard E. Hoare
Keyword(s):  
Land Use ◽  
Systematic Investigation ◽  
Current Evidence ◽  
Ecological Knowledge ◽  
Dispersal Patterns ◽  
Wild Mammals ◽  
Domestic Species ◽  
Animal Populations ◽  
African Mammals ◽  
Wide Range

The varying reasons are outlined for needing to control the movements or otherwise manage a wide range of African animal wildlife species by means of fencing. In all cases there is an underlying conflict of interest between people and animals — principally the larger mammals. Fencing is seen as the most powerful tool in this process of land-use division, and high expectations of fences are held by people who are adversely affected by wildlife activities and similarly by many conservationists. To date the main determinants in the siting and construction of fences have been political pressure or the availability of funds; wildlife fencing is perhaps the only factor having a substantial influence on ecosystems and animal populations that has remained virtually devoid of any serious input of ecological knowledge, of systematic investigation, or of environmental legislation.The wild species requiring management are many and varied in individual size, group size, and dispersal patterns; they also exhibit an array of special behaviours when confronted with a barrier. This means that any barrier will come under very variable levels and types of challenge, and that the effects of it on the biology of both target and non-target species must be carefully considered.Research on the behaviour of animals at fences has been limited, being mostly confined to domestic species or non-African wildlife. Certainly, very little systematic investigation has been carried out to determine whether fences have achieved their objectives or been economically justified, and to what extent they have caused environmental side-effects on the population dynamics of animals or the disturbance of plant communities.Current evidence suggests that electric or power fences are an increasingly efficient way of managing wild mammals and that fencing programmes should become more deflecting than encircling. Fences create ‘hard edges’ between dissimilar forms of land-use and cause long-term inflexibility that limits planning and forecloses options. As the pressure for land becomes more and more acute, the control of wildlife with the help of fences needs to develop into a specialized field of its own, based on sounder ecological, sociological, and economic, principles than hitherto, within the expanding scope of adaptive wildlife management.

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