scholarly journals The Effects of Habitat Modification on a Spotted Frog Population in Yellowstone National Park

1993 ◽  
Vol 17 ◽  
pp. 3-13
Author(s):  
Debra Patla ◽  
Charles Peterson
Keyword(s):  
Landscape Connectivity ◽  
Habitat Destruction ◽  
Habitat Modification ◽  
Population Declines ◽  
Amphibian Species ◽  
Amphibian Population ◽  
Breeding Sites ◽  
Population Responses ◽  
Sustainable Resource Use

Declines and extinctions of many populations of amphibians have been noted worldwide in recent years (Corn and Fogelman 1984, Beiswenger 1986, McAllister and Leonard 1990, Wake and Morowitz 1990, Wake 1991, Adler 1992). Habitat modifications due to human activities may contribute to many of these declines. Habitat may be destroyed overtly, or it may be fragmented. Fragmentation results in reduced area, a differential loss of important habitat components, and increased isolation of populations (Wyman 1990). The persistence of amphibians in areas where modifications short of total habitat destruction occur depends on the preservation of essential habitat components and landscape connectivity that allows individual animals access to breeding, foraging, and wintering sites (Sinsch 1989). Long-term persistence also may rely on the immigration of individuals from other populations (Pechmann et al. 1991, Sjogren 1991). Our efforts to conserve amphibian species and to establish methods of sustainable resource use depend on our understanding of habitat fragmentation and knowledge of the behavioral and population responses to different types of habitat modifications (Gibbons 1988, Groom and Schumaker 1993). Few studies have addressed these types of questions. Notable exceptions include some studies on the effects of logging (Corn and Bury 1989) and acidification (Wyman and Hawksley-Lescault 1988, Harte and Hoffman 1989, Corn and Vertucci 1992). In Europe, researchers and wildlife conservationists are investigating the impacts of roads on amphibians and attempting to find solutions to fragmentation and mortality effects (Langton 1989), but this concern has not yet received noticeable attention in North America. We lack studies evaluating the relative importance and integration of foraging areas, hibernacula, breeding sites, areas occupied pre- and post-breeding, and dispersal routes connecting these areas. With these kinds of information, researchers and land managers will acquire the ability to better analyze, predict, and mitigate the effects of habitat modifications that are sources of amphibian population declines.

scholarly journals The Effects of Habitat Modification on a Spotted Frog Population in Yellowstone National Park

1994 ◽  
Vol 18 ◽  
pp. 135-144
Author(s):  
Debra Patla ◽  
Charles Peterson
Keyword(s):  
Landscape Connectivity ◽  
Habitat Destruction ◽  
Habitat Modification ◽  
Population Declines ◽  
Amphibian Species ◽  
Amphibian Population ◽  
Breeding Sites ◽  
Population Responses ◽  
Different Types

Declines and extinctions of many populations of amphibians have been noted worldwide in recent years (Corn and Fogelman 1984, Beiswenger 1986, McAllister and Leonard 1990, Wake and Morowitz 1990, Wake 1991, Adler 1992). Habitat modifications due to human activities may contribute to many of these declines. Habitat may be destroyed overtly, or it may be fragmented. Fragmentation results in reduced area, a differential loss of important habitat components, and increased isolation of populations (Wyman 1990). The persistence of amphibians in areas where modifications short of total habitat destruction depends on the preservation of essential habitat components and landscape connectivity that allows individual animals access to breeding, foraging, and wintering sites (Sinsch 1989). Long-term persistence also may rely on the immigration of individuals from other populations (Pechmann et al. 1991, Sjogren 1991). Although our efforts to conserve amphibian species depend on our understanding of habitat fragmentation and knowledge of the behavioral and population responses to different types of habitat modifications (Gibbons 1988, Groom and Schumaker 1993), few studies have addressed these types of questions for amphibians. Notable exceptions include some studies on the effects of logging (Corn and Bury 1989) and acidification (Wyman and Hawksley-Lescault 1988, Harte and Hoffman 1989, Corn and Vertucci 1992). In Europe, researchers and wildlife conservationists are investigating the impacts of roads on amphibians and attempting to find solutions to fragmentation and mortality effects (Langton 1989), but this concern has not yet received noticeable attention in North America. We lack studies evaluating the relative importance and integration of foraging areas, hibernacula, breeding sites, areas occupied pre- and post-breeding, and dispersal routes connecting these areas. With these kinds of information, researchers and land managers will be better able to analyze, predict, and mitigate the effects of habitat modifications that are sources of amphibian population declines.

scholarly journals Composition of symbiotic bacteria predicts survival in Panamanian golden frogs infected with a lethal fungus

2015 ◽  
Vol 282 (1805) ◽  
pp. 20142881 ◽  
Author(s):  
Matthew H. Becker ◽  
Jenifer B. Walke ◽  
Shawna Cikanek ◽  
Anna E. Savage ◽  
Nichole Mattheus ◽  
...  
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Population Declines ◽  
Amphibian Species ◽  
Amphibian Population ◽  
New Approach ◽  
Skin Bacteria ◽  
Probiotic Treatment ◽  
Host Health ◽  
The Face ◽  
Inhibitory Bacteria

Symbiotic microbes can dramatically impact host health and fitness, and recent research in a diversity of systems suggests that different symbiont community structures may result in distinct outcomes for the host. In amphibians, some symbiotic skin bacteria produce metabolites that inhibit the growth of Batrachochytrium dendrobatidis (Bd), a cutaneous fungal pathogen that has caused many amphibian population declines and extinctions. Treatment with beneficial bacteria (probiotics) prevents Bd infection in some amphibian species and creates optimism for conservation of species that are highly susceptible to chytridiomycosis, the disease caused by Bd. In a laboratory experiment, we used Bd-inhibitory bacteria from Bd-tolerant Panamanian amphibians in a probiotic development trial with Panamanian golden frogs, Atelopus zeteki , a species currently surviving only in captive assurance colonies. Approximately 30% of infected golden frogs survived Bd exposure by either clearing infection or maintaining low Bd loads, but this was not associated with probiotic treatment. Survival was instead related to initial composition of the skin bacterial community and metabolites present on the skin. These results suggest a strong link between the structure of these symbiotic microbial communities and amphibian host health in the face of Bd exposure and also suggest a new approach for developing amphibian probiotics.

scholarly journals Infectious disease threats to amphibian conservation

2018 ◽  
Vol 27 (Supplement) ◽  
pp. 81-90
Author(s):  
A.A. Cunningham
Keyword(s):  
Infectious Disease ◽  
Batrachochytrium Dendrobatidis ◽  
Biodiversity Loss ◽  
Amphibian Conservation ◽  
Disease Spread ◽  
Population Declines ◽  
Amphibian Species ◽  
Late 20Th Century ◽  
Amphibian Population ◽  
In The Wild

The unexplained decline of amphibian populations across the world was first recognised in the late 20th century. When investigated, most of these “enigmatic” declines have been shown to be due to one of two types of infectious disease: ranavirosis caused by infection with FV3-like ranavirus or with common midwife toad virus, or chytridiomycosis caused by infection with Batrachochytrium dendrobatidis or B. salamandrivorans. In all cases examined, infection has been via the human-mediated introduction of the pathogen to a species or population in which it has not naturally co-evolved. While ranaviruses and B. salamandrivorans have caused regionally localised amphibian population declines in Europe, the chytrid fungus, B. dendrobatidis, has caused catastrophic multi-species amphibian population declines and species extinctions globally. These diseases have already caused the loss of amphibian biodiversity, and over 40% of known amphibian species are threatened with extinction. If this biodiversity loss is to be halted, it is imperative that regulations are put in place – and enforced – to prevent the spread of known and yet-to-be discovered amphibian pathogens. Also, it is incumbent on those who keep or study amphibians to take measures to minimise the risk of disease spread, including from captive animals to those in the wild.

scholarly journals Forecasting changes in amphibian biodiversity: aiming at a moving target

2005 ◽  
Vol 360 (1454) ◽  
pp. 309-314 ◽  
Author(s):  
James P Collins ◽  
Tim Halliday
Keyword(s):  
Time Series ◽  
Population Size ◽  
Single Species ◽  
High Rate ◽  
Population Declines ◽  
Amphibian Species ◽  
Statistical Designs ◽  
Millennium Assessment ◽  
The Tropics

Amphibian population declines and sudden species' extinctions began to be noted at the beginning of the 1980s. Understanding the causes of the losses is hampered by our poor knowledge of the amphibian fauna in many parts of the world. Amphibian taxa are still being described at a high rate, especially in the tropics, which means that even quantifying species lost as a percentage of the current fauna can be a misleading statistic in some parts of the globe. The number of species that have gone missing is only one measure of the loss of biodiversity. Long-term studies of single-species populations are needed, but this approach has its limits. Amphibian populations often show great annual variation in population size making it difficult, if not impossible, to use short-term studies as a basis for deciding if a population is increasing or decreasing in the long term. Aggregating single studies into databases and searching for patterns of variation is a way of overcoming this limitation. Several databases on species and population time series are available or in development. These records show that declines are continuing worldwide with some species and populations, especially in the tropics and at higher elevations, at greater risk of extinction than others. Unfortunately, amphibian databases with population time series have much less information for the tropics compared to the temperate zone, and less for Africa and Asia compared with Europe and North America. Focusing limited resources using comprehensive statistical designs is a way to maximize the efficiency and effectiveness of monitoring efforts. It is clear that, in the first decades of the twenty-first century, the regions of the globe with the highest diversity of amphibian species will experience the greatest rates of decrease of forests and increase in human population size, fertilizer use, agricultural production, creation of new croplands and irrigation. Many of these changes are likely negatively to affect amphibian species diversity, and their influence must be understood before concluding, at least for amphibians, that the 2010 millennium assessment goal of significantly reversing the rate of loss of Earth's biodiversity can be met.

scholarly journals Forest fragmentation in the temperate zone and its effects on migratory songbirds

1994 ◽  
Vol 4 (2-3) ◽  
pp. 233-249 ◽  
Author(s):  
Scott K. Robinson ◽  
David S. Wilcove
Keyword(s):  
Forest Fragmentation ◽  
Tropical Deforestation ◽  
Temperate Zone ◽  
Breeding Habitat ◽  
Neotropical Migrants ◽  
Population Declines ◽  
Migratory Songbirds

SummaryAlthough much attention has been paid to the impacts of tropical deforestation on populations of Neotropical migrants, fragmentation of breeding habitat may be an equally serious problem for many of these birds. Populations of many migrant songbirds have been declining in recent decades, especially within small woodlots. Censuses from woodlots of different sizes also consistently show that many migrant songbirds are area-sensitive, i.e. they are absent from all but the largest woodlots in a region. In contrast, long-term censuses from large, unfragmented forests show few consistent patterns of decline in Neotropical migrants. Population declines are therefore linked to forest fragmentation because they are most pronounced in small, isolated woodlots.

Amphibian Population Declines and Climate Change

2011 ◽  
pp. 29-54 ◽  
Author(s):  
Andrew Blaustein ◽  
Catherine Searle ◽  
Betsy Bancroft ◽  
Joshua Lawler
Keyword(s):  
Climate Change ◽  
Population Declines ◽  
Amphibian Population

Acidic deposition as an unlikely cause for amphibian population declines in the Sierra Nevada, California

1994 ◽  
Vol 69 (2) ◽  
pp. 155-161 ◽  
Author(s):  
David F. Bradford ◽  
Malcolm S. Gordon ◽  
Dale F. Johnson ◽  
Russel D. Andrews ◽  
W.Bryan Jennings
Keyword(s):  
Sierra Nevada ◽  
Acidic Deposition ◽  
Population Declines ◽  
Amphibian Population

scholarly journals Urbanization and Population Genetic Structure of the Panama City crayfish (Procambarus econfinae)

2019 ◽  
Vol 111 (2) ◽  
pp. 204-215
Author(s):  
Sarah I Duncan ◽  
Ellen P Robertson ◽  
Robert J Fletcher ◽  
James D Austin
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Habitat Loss ◽  
Legal Protection ◽  
Habitat Modification ◽  
Panama City ◽  
Habitat Patches ◽  
Anthropogenic Habitat ◽  
Habitat Loss And Fragmentation

Abstract For species with geographically restricted distributions, the impacts of habitat loss and fragmentation on long-term persistence may be particularly pronounced. We examined the genetic structure of Panama City crayfish (PCC), Procambarus econfinae, whose historical distribution is limited to an area approximately 145 km2, largely within the limits of Panama City and eastern Bay County, FL. Currently, PCC occupy approximately 28% of its historical range, with suitable habitat composed of fragmented patches in the highly urbanized western portion of the range and managed plantations in the more contiguous eastern portion of the range. We used 1640 anonymous single-nucleotide polymorphisms to evaluate the effects of anthropogenic habitat modification on the genetic diversity and population structure of 161 PCC sampled from across its known distribution. First, we examined urban habitat patches in the west compared with less-developed habitat patches in the east. Second, we used approximate Bayesian computation to model inferences on the demographic history of eastern and western populations. We found anthropogenic habitat modifications explain the genetic structure of PCC range-wide. Clustering analyses revealed significant genetic structure between and within eastern and western regions. Estimates of divergence between east and west were consistent with urban growth in the mid-20th century. PCC have low genetic diversity and high levels of inbreeding and relatedness, indicating populations are small and isolated. Our results suggest that PCC have been strongly affected by habitat loss and fragmentation and management strategies, including legal protection, translocations, or reintroductions, may be necessary to ensure long-term persistence.

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