scholarly journals Amphibian Declines in the Greater Yellowstone Ecosystem: Toads with Protection from Bacterial Disease

1997 ◽  
Vol 21 ◽  
pp. 81-98
Author(s):  
Jeremy Hawk ◽  
Charles Peterson
Keyword(s):  
Synergistic Effects ◽  
Large Population ◽  
Disease Process ◽  
Abundant Species ◽  
Amphibian Declines ◽  
Bacterial Disease ◽  
Population Declines ◽  
Amphibian Species ◽  
Endangered Status ◽  
Abundance And Distribution

During the past forty years, biologists have become increasingly concerned about the decline and disappearance of various amphibian species throughout the world (Wyman 1990, Wake 1991). An example of an amphibian decline in western North America is that of the Boreal Toad (Bufo boreas). A previously widespread and abundant species, the Boreal Toad has undergone large population declines and is now a candidate for threatened and endangered status in the eastern half of its range (Stebbins and Cohen 1995, Federal Register 1995). Decreases in Boreal Toad abundance and distribution have been observed in Colorado, eastern Wyoming, and eastern Utah (Com et al. 1989). From 1971-82, eleven Boreal Toad populations disappeared from the West Elk Mountains of Colorado (Carey 1993). During this eleven-year period, numerous individuals were observed exhibiting symptoms of redleg, a well­documented disease in amphibians caused by the bacterium Aeromonas hydrophila (Russel 1898, Emerson and Norris 1905, Kulp and Borden 1942, Reed and Toner 1942, Dusi 1949, Hunsaker and Potter 1960, Hird et. al. 1981, Nyman 1986, Carey 1993). This disease was considered responsible for the decline and ultimate extinction of these eleven toad populations. These extinctions led Carey to propose a hypothesis regarding the disease process which is stated as follows: (1) Some environmental factor or synergistic effects of more than one factor changes sufficiently to cause sublethal "stress;" (2) This stress directly causes suppression of the immune system, or indirectly causes immunosuppression by effecting elevated secretion of adrenal cortical hormones; (3) Immunosuppression, coupled with the apparent effect of cold body temperatures on the ability of immune systems of ectothermic animals to fight disease, leads to infection by Aeromonas or other infectious agents, and to subsequent death of individuals and extinction of populations.

scholarly journals Inconsistent effects of urbanization on amphibian genetic diversity

2020 ◽  
Author(s):  
Chloé Schmidt ◽  
Colin J Garroway
Keyword(s):  
Genetic Diversity ◽  
Population Size ◽  
Effective Population Size ◽  
Habitat Loss ◽  
Gene Diversity ◽  
Amphibian Declines ◽  
Population Declines ◽  
Effective Population ◽  
Negative Effects ◽  
Amphibian Species

AbstractHabitat loss and fragmentation are leading causes of vertebrate population declines. These declines are thought to be partly due to decreased connectivity and habitat loss reducing population sizes in human transformed habitats. With time this can lead to reduced effective population size and genetic diversity which restricts the ability of wildlife to cope with environmental change through genetic adaptation. However, it is not well understood whether these effects are generally applicable across taxa. Here, we repurposed and synthesized raw microsatellite data from online repositories from 19 amphibian species sampled at 554 sites in North America. For each site, we estimated gene diversity, allelic richness, effective population size, and population differentiation. Using binary urban-rural census designations, and continuous measures of human population density and the Human Footprint Index, we tested for generalizable effects of human land use on amphibian genetic diversity. We found no consistent relationships for any of our genetic metrics. While we did not detect directional effects for most species, a few generalist species responded positively to urbanization. These results contrast with consistent negative effects of urbanization in mammals and species specific positive and negative effects in birds. In the context of widespread amphibian declines, our results suggest that habitat loss in human transformed habitats is a more immediate concern than declining genetic diversity in populations that persist.

Polyphenol intake is associated with low-grade inflammation, using a novel data analysis from the Moli-sani study

2016 ◽  
Vol 115 (02) ◽  
pp. 344-352 ◽  
Author(s):  
George Pounis ◽  
Marialaura Bonaccio ◽  
Augusto Di Castelnuovo ◽  
Simona Costanzo ◽  
Amalia De Curtis ◽  
...  
Keyword(s):  
Synergistic Effects ◽  
Dietary Assessment ◽  
Large Population ◽  
Total Content ◽  
Holistic Approach ◽  
Population Based ◽  
Low Grade ◽  
Polyphenol Content ◽  
Negatively Associated ◽  
Low Grade Inflammation

SummaryThe association of polyphenol content of human diet with low-grade inflammation is not yet fully understood. It was the objective of this study to evaluate the association of flavonoid and lignan intake with frequently used and easily applicable in clinical practice low-grade inflammation biomarkers, in a novel holistic approach. A total of 5,948 women and 5,965 men (aged ≥ 35years) were analysed from the Moli-sani cohort, randomly recruited from the general population. The EPIC-FFQ was used for dietary assessment. Flavonol, flavone, flavanone, flavanol, anthocyanin, isoflavone and lignan intakes were calculated using Eurofir eBASIS and the polyphenol antioxidant content (PAC)-score was constructed to assess the total content of diet in these nutrients. CRP levels, WBC and PLT count and granulocyte to lymphocyte ratio were conceived as low-grade inflammation biomarkers. INFLA-score was constructed summarizing synergistic effects of these biomarkers. The INFLA-score was negatively associated with PAC-score in different levels of adjustment, in both genders (for all β-coef< 0, P< 0.05). 10 units increase in PAC-score was associated with 5–8 % decrease in the likelihood of higher low-grade inflammation status (i. e. higher quartile of INFLA-score) in men and women (odds ratio [ORs] 0.92 to 0.95, p< 0.05). The total variation of INFLA-score that was explained by PAC-score was estimated to be 16.7 % in women and 9.1 % in men (%R2=16.7 and 9.1). In conclusion, polyphenol content of diet evaluated in a holistic approach was negatively associated with a score of low-grade inflammation biomarkers in a large population based study. For the first time low-grade inflammation was evaluated in a holistic way through INFLA-score and was associated with polyphenol content of diet.Supplementary Material to this article is available online at www.thrombosis-online.com.

scholarly journals Status, Appropriate Sampling Scheme, and Movement in the Tiger Salamander (Ambystoma tigrinum) in Yellowstone National Park

2002 ◽  
Vol 26 ◽  
pp. 80-81
Author(s):  
Charles Peterson ◽  
Stephen Spear
Keyword(s):  
Spatial Scale ◽  
Average Distance ◽  
Current Trend ◽  
Amphibian Declines ◽  
Current Status ◽  
Ambystoma Tigrinum ◽  
Terrestrial Habitat ◽  
Amphibian Species ◽  
Core Habitat ◽  
Breeding Pond

Due to the current trend of amphibian declines (Wake 1998, Alford and Richards 1999, Semlitsch 2000), the monitoring and study of amphibian populations has become increasingly necessary. To properly do such studies, we must consider several issues. Some of these include the detectability of the species at a site, current status of the population, and the spatial scale for sampling of a population. Determining the detectability of a species is important to consider because some amphibian species may have different difficulties of detection. Therefore, if a species is difficult to observe, it may occupy a greater number of sites than a survey indicates (MacKenzie et al. 2002). The appropriate spatial scale is also important for monitoring studies. For example, in a pond breeding amphibian, do one or two breeding ponds with the appropriate terrestrial habitat constitute the correct sampling area for a population, or does a population utilize multiple ponds within a larger terrestrial area? If the sampling scale is not appropriate, then any conclusions made may be inaccurate (Wiens 1989). In addition, understanding the terrestrial habitat use of pond breeding amphibians is important for both monitoring and conservation reasons. Many pond-breeding amphibians use the ponds for breeding and then utilize terrestrial zones around the pond for the rest of the year. The total area that is encompassed by these terrestrial zones is known as the terrestrial "buffer zone" or core habitat area for that population (Semlitsch 1998). To identify these core habitat areas, we must know not only the distance that the amphibians physically move from the breeding pond, but also the type of habitat that they will use. For example, short, steep slopes or rivers can serve as a barrier to amphibian movement (Laan and Verboom 1990, Storfer 1999), even if they are within the movement range of a population. Understanding individual movement may also give insights into the spatial population structure of the species. If we can identify the average distance of movement, we can then extrapolate if a breeding pond is likely to have an isolated subpopulation based on its distance from other ponds.

scholarly journals Fungal infection, decline and persistence in the only obligate troglodytic Neotropical salamander

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9763
Author(s):  
Mizraim Olivares-Miranda ◽  
Vance T. Vredenburg ◽  
Julio C. García-Sánchez ◽  
Allison Q. Byrne ◽  
Erica B. Rosenblum ◽  
...  
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Infection Intensity ◽  
Sampling Technique ◽  
Sympatric Species ◽  
Amphibian Declines ◽  
Small Range ◽  
Museum Specimens ◽  
Amphibian Species ◽  
Extant Population ◽  
Epidemic Wave

The fungal pathogen Batrachochytrium dendrobatidis (Bd) is implicated in global mass die-offs and declines in amphibians. In Mesoamerica, the Bd epidemic wave hypothesis is supported by detection of Bd in historic museum specimens collected over the last century, yet the timing and impact of the early stages of the wave remain poorly understood. Chiropterotriton magnipes, the only obligate troglodytic Neotropical salamander, was abundant in its small range in the decade following its description in 1965, but subsequently disappeared from known localities and was not seen for 34 years. Its decline is roughly coincident with that of other populations of Neotropical salamanders associated with the invasion and spread of Bd. To determine the presence and infection intensity of Bd on C. magnipes and sympatric amphibian species (which are also Bd hosts), we used a noninvasive sampling technique and qPCR assay to detect Bd on museum specimens of C. magnipes collected from 1952 to 2012, and from extant populations of C. magnipes and sympatric species of amphibians. We also tested for the presence of the recently discovered Batrachochytrium salamandivorans (Bsal), another fungal chytridiomycete pathogen of salamanders, using a similar technique specific for Bsal. We did not detect Bd in populations of C. magnipes before 1969, while Bd was detected at low to moderate prevalence just prior to and during declines. This pattern is consistent with Bd-caused epizootics followed by host declines and extirpations described in other hosts. We did not detect Bsal in any extant population of C. magnipes. We obtained one of the earliest positive records of the fungus to date in Latin America, providing additional historical evidence consistent with the Bd epidemic wave hypothesis. Genotyping results show that at least one population is currently infected with the Global Panzootic Lineage of Bd, but our genotyping of the historical positive samples was unsuccessful. The lack of large samples from some years and the difficulty in genotyping historical Bd samples illustrate some of the difficulties inherent in assigning causality to historical amphibian declines. These data also provide an important historical baseline for actions to preserve the few known remaining populations of C. magnipes.

scholarly journals Ancestral chytrid pathogen remains hypervirulent following its long coevolution with amphibian hosts

2019 ◽  
Vol 286 (1904) ◽  
pp. 20190833 ◽  
Author(s):  
Minjie Fu ◽  
Bruce Waldman
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Population Declines ◽  
Amphibian Species ◽  
South Korean ◽  
Global Pandemic ◽  
Litoria Caerulea ◽  
Experimental Treatments ◽  
Amphibian Chytrid Fungus ◽  
Genomic Recombination ◽  
Blank Solution

Many amphibian species around the world, except in Asia, suffer morbidity and mortality when infected by the emerging infectious pathogen Batrachochytrium dendrobatidis (Bd). A lineage of the amphibian chytrid fungus isolated from South Korean amphibians (BdAsia-1) is evolutionarily basal to recombinant global pandemic lineages (BdGPL) associated with worldwide amphibian population declines. In Asia, the Bd pathogen and its amphibian hosts have coevolved over 100 years or more. Thus, resilience of Asian amphibian populations to infection might result from attenuated virulence of endemic Bd lineages, evolved immunity to the pathogen or both. We compared susceptibilities of an Australasian amphibian, Litoria caerulea , known to lack resistance to BdGPL, with those of three Korean species, Bufo gargarizans , Bombina orientalis and Hyla japonica , after inoculation with BdAsia-1, BdGPL or a blank solution. Subjects became infected in all experimental treatments but Korean species rapidly cleared themselves of infection, regardless of Bd lineage. They survived with no apparent secondary effects. By contrast, L. caerulea , after infection by either BdAsia-1 or BdGPL, suffered deteriorating body condition and carried progressively higher Bd loads over time. Subsequently, most subjects died. Comparing their effects on L. caerulea , BdAsia-1 induced more rapid disease progression than BdGPL. The results suggest that genomic recombination with other lineages was not necessary for the ancestral Bd lineage to evolve hypervirulence over its long period of coevolution with amphibian hosts. The pathogen's virulence may have driven strong selection for immune responses in endemic Asian amphibian host species.

Genetic markers reveal high PIT tag retention rates in giant salamanders (Cryptobranchus alleganiensis)

2012 ◽  
Vol 33 (2) ◽  
pp. 313-317 ◽  
Author(s):  
Shem D. Unger ◽  
Nicholas G. Burgmeier ◽  
Rod N. Williams
Keyword(s):  
Cost Effective ◽  
Retention Rates ◽  
Population Declines ◽  
Pit Tag ◽  
Amphibian Species ◽  
Pit Tags ◽  
Tag Retention ◽  
Cryptobranchus Alleganiensis ◽  
Genetic Tagging ◽  
Secondary Methods

Estimation of population size using mark-recapture (MRR) methods are based on the fundamental assumption that individuals retain their marks throughout the course of study. Passive Integrated Transponder (PIT) tags are useful as a cost effective, reliable marking method in many amphibian and reptile species. Few studies however, use secondary methods to evaluate tag retention rates. Failure to do so can lead to biased population estimates, erroneous conclusions, and thus poor management decisions. Surprisingly, estimates of PIT tag retention are currently lacking for the majority of amphibian species, many of which are experiencing population declines. Herein, we use genetic tagging to assess the retention of PIT tags of the eastern hellbender (Cryptobranchus alleganiensis alleganiensis). We captured and tagged 78 individuals across 35 sites. Recapture rate was 24% and genetic tagging revealed 100% tag retention across all recaptured individuals.

scholarly journals Recovery and resiliency of skin microbial communities on the southern leopard frog (Lithobates sphenocephalus) following two biotic disturbances

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Denita M. Weeks ◽  
Matthew J. Parris ◽  
Shawn P. Brown
Keyword(s):  
Microbial Communities ◽  
Fungal Pathogen ◽  
Bacterial Species ◽  
Leopard Frog ◽  
Multiple Time ◽  
Population Declines ◽  
Community Interactions ◽  
Amphibian Species ◽  
Functional Relationships ◽  
Species Specific

Abstract Background Microorganisms have intimate functional relationships with invertebrate and vertebrate taxa, with the potential to drastically impact health outcomes. Perturbations that affect microbial communities residing on animals can lead to dysbiosis, a change in the functional relationship, often associated with disease. Batrachochytrium dendrobatidis (Bd), a fungal pathogen of amphibians, has been responsible for catastrophic amphibian population declines around the globe. Amphibians harbor a diverse cutaneous microbiome, including some members which are known to be antagonistic to Bd (anti-Bd). Anti-Bd microorganisms facilitate the ability of some frog populations to persist in the presence of Bd, where other populations that lack anti-Bd microorganisms have declined. Research suggests disease-antagonistic properties of the microbiome may be a function of microbial community interactions, rather than individual bacterial species. Conservation efforts have identified amphibian-associated bacteria that exhibit anti-fungal properties for use as ‘probiotics’ on susceptible amphibian populations. Probiotic application, usually with a single bacterial species, may benefit from a greater understanding of amphibian species-specific microbiome responses to disturbances (e.g. dysbiosis vs. recovery). We assessed microbiome responses to two microbial disturbance events over multiple time points. Results Exposing Lithobates sphenocephalus (southern leopard frog) adults to the biopesticidal bacteria Bacillus thuringiensis, followed by exposure to the fungal pathogen Bd, did not have long term impacts on the microbiome. After initial shifts, microbial communities recovered and returned to a state that resembled pre-disturbance. Conclusions Our results indicate microbial communities on L. sphenocephalus are robust and resistant to permanent shifts from some disturbances. This resiliency of microbial communities may explain why L. sphenocephalus is not experiencing the population declines from Bd that impacts many other species. Conservation efforts may benefit from studies outlining amphibian species-specific microbiome responses to disturbances (e.g. dysbiosis vs. recovery). If microbial communities on a threatened amphibian species are unlikely to recover following a disturbance, additional measures may be implemented to ameliorate the impacts of physical and chemical stressors on host-associated microbial communities.

Human-provoked amphibian decline in central Italy and the efficacy of protected areas

2010 ◽  
Vol 37 (7) ◽  
pp. 547 ◽  
Author(s):  
Manuela D'Amen ◽  
Biancamaria Pietrangeli ◽  
Marco A. Bologna
Keyword(s):  
Protected Areas ◽  
Multiple Stressors ◽  
Population Decline ◽  
Central Italy ◽  
Negative Relationship ◽  
Climatic Conditions ◽  
Amphibian Declines ◽  
Additive Models ◽  
Management Approach ◽  
Amphibian Species

Context Today, more than 32% of amphibian species are threatened and more than 43% face a steep decline in numbers. Most species are being affected simultaneously by multiple stressors and habitat protection is often inadequate to prevent declines. Aims The main goal of the present research was to understand the consequences of alternative human land use in producing landscape disturbance for amphibians. At the same time, we also evaluated the effect of changing climatic conditions as additional potential drivers of population decline. Another goal was to determine whether and to what extent the existing nature reserves have been effective in protecting species in recent decades. Methods We used generalised additive models (GAMs) to investigate the association between the state (stable/decline) of amphibian populations in 5 × 5 km cells in central Italy and proxies of different typology of anthropogenic stressors, climatic variables and protection measures. Key results We found a significant association between anthropogenic landscape modifications and species decline. This negative relationship was revealed with agricultural predictors for the majority of the species, whereas urban fabrics had a slightly smaller impact. We found significant associations between amphibian declines and climatic variation, particularly the increasing number of dry days. Protected areas protected declines of two species only. Conclusions Our results showed that the status of amphibians in this region warrants greater attention than has been given previously. The detrimental effect of agricultural practices, combined with increasing aridity, makes amphibian populations particularly susceptible to extinction, and the conservation measures applied till now are inadequate for species protection in this region. Implications Our results should stimulate the implementation of environmental policies that focus not only on the protection of single habitats, but also on ensuring the environmental quality of the surrounding landscapes. Moreover, an adaptive management approach should be applied to take into account future modification of hydrology and climate.

EPIPELAGIC EUPHAUSIDS (EUPHAUSIACEA) AND SPRING MESOSCALE FEATURES IN THE GULF OF MEXICO

Crustaceana ◽  
1999 ◽  
Vol 72 (4) ◽  
pp. 391-404 ◽  
Author(s):  
◽  
Keyword(s):  
Gulf Of Mexico ◽  
Surface Waters ◽  
Abundant Species ◽  
Time Of Day ◽  
Migratory Behaviour ◽  
The Third ◽  
Density Values ◽  
Hydrographic Features ◽  
Anticyclonic Eddies ◽  
Abundance And Distribution

AbstractThe abundance and distribution of 21 species of euphausids collected in surface waters (0-200 m) at 69 stations of the Gulf of Mexico and the Yucatan Shelf was analyzed. Zooplankton samples were taken during the JS8601 cruise on board the R/V "Justo Sierra" of the UNAM, in April-May, 1986. During this survey mesoscale hydrographic features such as anticyclonic and cyclonic gyres, and upwelling, were detected in the area. The most abundant species was Stylocheiron carinatum (29.86%), followed by Euphausia tenera (19.97%) and S. suhmi (15.18%). Species richness increased at night: densities were 3.07 times higher then. Apparently, the migratory behaviour, of euphausids buffered the expected effect of the mesoscale features in the local euphausid community. The Bray-Curtis Index revealed three clusters of stations. The first one represented the influence of coastal and shelf waters on the euphausid community. The second group is a mixed oceanic-shelf community, and the third one was related to the Gulf oligotrophic oceanic waters. A fourth group included shallow areas in which no euphausids occurred. The relatively poor anticyclonic eddies did not influence the local euphausid community although low euphausid densities were expected. The relatively richer features, the cyclones, showed higher average densities. Euphausid densities related to the influence of upwelling areas showed density values similar to those recorded in the anticyclones. Two species (S. suhmi and S. carinatum) occurred in all the Gulf of Mexico regardless of the mesoscale environments or the time of day. L'abondance et la repartition de 21 especes d'Euphausiaces recoltes dans les eaux de surface (0-200 m) sur 69 stations du Golfe du Mexique et du plateau du Yucatan ont ete analysees. Les echantillons de zooplancton ont ete preleves au cours de la campagne JS8601 a bord du R/V "Justo Sierra" de l'UNAM, en avril-mai 1986. Au cours de cette mission, de variations hydrographiques d'amplitude moyenne comme les phenomenes cycloniques et anticycloniques, ainsi que l'upwelling, ont ete detectees dans la region. Les especes les plus abondantes etaient Stylocheiron carinatum (29,86%) suivie de Euphausia tenera (19,97%) et S. suhmi (15,18%). La richesse specifique augmentait dans les echantillons nocturnes; les densites etaient 3,07 fois plus elevees la nuit. Apparemment le comportement migratoire des Euphausiaces compensait l'effet attendu des particularites hydrographiques dans la communaute locale d'Euphausiaces. L'indice de Bray-Curtis a revele trois groupes de stations. Le premier representait l'influence des eaux cotieres et de la plate-forme continentale sur la communaute des Euphausiaces. Le second groupe etait une communaute mixte oceanique-plate-forme et le troisieme se rapportait aux eaux oceaniques oligotrophes du Golfe. Un quatrieme groupe incluait les zones peu profondes sans Euphausiaces. Les phenomenes anticycloniques relativement faibles n'avaient pas d'influence sur la communaute locale des Euphausiaces, bien que l'on se soit attendu a des densites d'Euphausiaces basses. Les phenomenes relativement plus marques, les cyclones, ont montre des densites moyennes plus elevees. Les densites d'Euphausiaces liees a l'influence des zones d'upwelling ont indique des valeurs similaires a celles relevees pour les anticyclones. Deux especes (S. suhmi and S. carinatum) sont presentes dans tout le Golfe du Mexique independamment des environnements consideres et du moment de la journee.

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