The movements of Western Chorus Frogs (Pseudacris, triseriata triseriata) were studied from March, 1970, to March, 1971, at the Robert H. and Esther L. Cooper Woodland Area near Muncie, Delaware County, Indiana. The objectives of the study were to determine: (1) the time and rate of dispersal from the breeding pool; (2) the day-to-day movements, including the time and minimal distance traveled; (3) the preferred cover or microhabitat; and (4) the site of hibernation.Seventy-three Chorus Frogs were tagged with approximately 50 μc Co60 and toe-clipped, and each was released at its capture site. The frogs were then sought at intervals by surveying the area with a portable survey meter equipped with a scintillation probe. The location of each recovered specimen and a description of the recapture site was recorded.Sixty-two individual specimens were recaptured at least one time. The number of recaptures for each specimen was variable, and the maximum number of recaptures for a single specimen was 26 times. In all, 324 recoveries of tagged specimens were made. The tagged specimens graduallybecame lost to the investigator, and the last specimen was found on August 4. The longest period of contact for an individual frog was 134 days.Some Chorus Frogs began leaving the breeding pools soon after the first eggs were observed on April 1. The exodus appeared to be gradual as a few (one to eight) additional tagged specimens were found out of the pools throughout April and early May. Four of these specimens returned at least once to their original pool and seventeen frogs entered a second pool.From a single attempt to monitor the overnight activities of these frogs, it appears that they remain quiescent during the daylight hours and become active between dusk and dawn.The minimal distances traveled by the tagged, specimens during the study are more a function of the length of the contact period and the number of recaptures than of the activity of the frogs. The average rate of movement for all of the specimens over the entire study period was 11.3 feet/day. However, the fastest observed rate of movement for a single specimen between two recapture sites was 138 feet/day. The greatest straight distance any specimen was found from its original pool was 700 feet. Most recaptures were within 500 feet of the pools where the specimens were tagged.In 213 (91.3%) of the 234 recaptures made daylight hours after the frogs left the breeding pools,the frogs were hidden in the leaf litter of the woods or dead grasses of the grassland. In the remaining recaptures the frogs were hidden under small objects. The frogs seemed to prefer moist rather than dry or wet cover, but this is possibly more a reflection of conditions at the time of the study than a preference on the part of the frogs.The gradual disappearance of the tagged frogs from the study area, the woodland situation of the breeding pools, and the concentration of searching efforts in the vicinity of the pools prevented the determination of the preferred habitat type (woodland or grassland). Also, because of the loss of all tagged specimens by the end of summer, hibernating sites were not located.There is evidence that the gradual disappearance of tagged specimens may be explained by predation or movement of the frogs underground or out of the study area. Other frogs lost their cobalt wires and could no longer be located.

The relationship between habitat preferences and rates of dispersal and directional orientation across different vegetations was investigated using captures from an array of drift fences for Pseudacris triseriata , at a breeding pond near Boucherville, Quebec. Growth rates for juveniles were similar across the study area, suggesting that food was not limiting and movement is related to habitat preference. Frog residence time in habitat enclosures, and between fence arrays was significantly longer for frogs in humid prairie vegetation compared to those in shrubby vegetation. The number of frogs caught per metre of fence in humid prairies was also on average higher than either shrubby or arid prairie vegetations. Together both migration rates and captures per metre of fence suggest that the preferred habitat for P. triseriata is humid prairie vegetation (e.g. Phalaris grass). Target-oriented dispersal may explain why similar numbers of P. triseriata were captured in both shrubby and humid prairie vegetation, despite the perceived preference for humid prairies over shrubby vegetation. The continued persistence of this population appears to be based on the recruitment of juveniles from the larval stage, and is also sensitive to the fecundity of the first time breeders.

No description available.

The movements of Western Chorus Frogs, Pseudacris triseriata triseriata, were studied from May 1, 1975, to May 16, 1975, on the Robert H. and Esther L. Cooper Woodland Area near Muncie, Delaware County, Indiana. The purpose of the study was to obtain detailed information on the day-to-day and hour-to-hour movements and habitat selection of the species immediately following the breeding season.Five Chorus Frogs were tagged with approximately 50 μc Co60 , and were released at a common point near a forest grassland interface. Study frogs were then located at two hour intervals for several 24-hour or 48-hour periods by searching the area of previous contact with a portable survey meter equipped with a scintillation probe.Horizontal movements are apparently random in direction and not influenced by habitat or meteorologic conditions other than moisture. They occur during daylight hours and at night and seem only to be influenced by moisture conditions of the microhabitat.Vertical movements are also influenced by moisture conditions, and occur primarily just before and after dawn.Chorus Frog preference for either a grassland or forest habitat was not determined by this study.Ball State UniversityMuncie, IN 47306

abstract: Infectious diseases have emerged as a significant threat to wildlife. Environmental change is often implicated as an underlying factor driving this emergence. With this recent rise in disease emergence and the acceleration of environmental change, it is important to identify the environmental factors that alter host-pathogen dynamics and their underlying mechanisms. The emerging pathogen Batrachochytrium dendrobatidis (Bd) is a clear example of the negative effects infectious diseases can have on wildlife. Bd is linked to global declines in amphibian diversity and abundance. However, there is considerable variation in population-level responses to Bd, with some hosts experiencing marked declines while others persist. Environmental factors may play a role in this variation. This research used populations of pond-breeding chorus frogs (Pseudacris maculata) in Arizona to test if three rapidly changing environmental factors nitrogen (N), phosphorus (P), and temperature influence the presence, prevalence, and severity of Bd infections. I evaluated the reliability of a new technique for detecting Bd in water samples and combined this technique with animal sampling to monitor Bd in wild chorus frogs. Monitoring from 20 frog populations found high Bd presence and prevalence during breeding. A laboratory experiment found 85% adult mortality as a result of Bd infection; however, estimated chorus frog densities in wild populations increased significantly over two years of sampling despite high Bd prevalence. Presence, prevalence, and severity of Bd infections were not correlated with aqueous concentrations of N or P. There was, however, support for an annual temperature-induced reduction in Bd prevalence in newly metamorphosed larvae. A simple mathematical model suggests that this annual temperature-induced reduction of Bd infections in larvae in combination with rapid host maturation may help chorus frog populations persist despite high adult mortality. These results demonstrate that Bd can persist across a wide range of environmental conditions, providing little support for the influence of N and P on Bd dynamics, and show that water temperature may play an important role in altering Bd dynamics, enabling chorus frogs to persist with this pathogen. These findings demonstrate the importance of environmental context and host life history for the outcome of host-pathogen interactions. / Dissertation/Thesis / Ph.D. Biology 2012

Many prey species lack innate recognition of their potential predators. Hence, learning is required for them to recognize and respond to predation threats. When wild-caught, these same species may show amazing sophistication in their responses to predator cues. They are able to adjust the intensity of their antipredator responses to a particular predator according to the degree of threat posed by that predator. This ability is therefore acquired through learning. While many studies have shown that prey can learn to respond to predator cues through different learning modes, little is known about what the prey are actually learning. The results presented in this thesis show that learned predator recognition goes beyond the simple labelling of predators as dangerous. Using fathead minnows (Pimephales promelas), woodfrog (Rana sylvatica) tadpoles and boreal chorus frog (Pseudacris maculata) tadpoles, I demonstrated that a one time learning event, either through pairing with alarm cues or through social learning, was enough for prey to learn the level of threat associated with the novel predator cues. I showed that the level of danger associated with the predator cues was determined by the concentration of alarm cues when learning through pairing of alarm cues, or by the intensity of antipredator response displayed by the tutors and by the tutor-to-observer ratio when learning occurred through cultural transmission. Moreover, when subsequently exposed to predator cues, prey adjusted their antipredator responses according to the change in concentration of predator cues between the learning event and the subsequent exposure. Prey displayed stronger antipredator responses when exposed to higher concentrations of predator cues and vice versa. When minnows were provided with conflicting information about the danger level associated with a predator, they displayed a safety strategy and used the most recent information available to respond to predation threats. On a longer time scale, the data also suggest that woodfrog tadpoles are able to learn to respond to predation threats according to the risk posed by the predator at different times of day. Finally, I showed that prey learn to recognize particular characteristics of predators and can generalize their antipredator responses to novel species sharing those characteristics. However, generalization of predator recognition is dependent on the level of risk associated with the predator. Threat-sensitive learning is an extremely complex process shaped by the millions of years of selection imposed by predators on prey.

Many prey species lack innate recognition of their potential predators. Hence, learning is required for them to recognize and respond to predation threats. When wild-caught, these same species may show amazing sophistication in their responses to predator cues. They are able to adjust the intensity of their antipredator responses to a particular predator according to the degree of threat posed by that predator. This ability is therefore acquired through learning. While many studies have shown that prey can learn to respond to predator cues through different learning modes, little is known about what the prey are actually learning. The results presented in this thesis show that learned predator recognition goes beyond the simple labelling of predators as dangerous. Using fathead minnows (Pimephales promelas), woodfrog (Rana sylvatica) tadpoles and boreal chorus frog (Pseudacris maculata) tadpoles, I demonstrated that a one time learning event, either through pairing with alarm cues or through social learning, was enough for prey to learn the level of threat associated with the novel predator cues. I showed that the level of danger associated with the predator cues was determined by the concentration of alarm cues when learning through pairing of alarm cues, or by the intensity of antipredator response displayed by the tutors and by the tutor-to-observer ratio when learning occurred through cultural transmission. Moreover, when subsequently exposed to predator cues, prey adjusted their antipredator responses according to the change in concentration of predator cues between the learning event and the subsequent exposure. Prey displayed stronger antipredator responses when exposed to higher concentrations of predator cues and vice versa. When minnows were provided with conflicting information about the danger level associated with a predator, they displayed a safety strategy and used the most recent information available to respond to predation threats. On a longer time scale, the data also suggest that woodfrog tadpoles are able to learn to respond to predation threats according to the risk posed by the predator at different times of day. Finally, I showed that prey learn to recognize particular characteristics of predators and can generalize their antipredator responses to novel species sharing those characteristics. However, generalization of predator recognition is dependent on the level of risk associated with the predator. Threat-sensitive learning is an extremely complex process shaped by the millions of years of selection imposed by predators on prey.

The conservation of aquatic-breeding amphibian populations and their habitats is increasingly challenged by urban and rural development, which is occurring more intensively and more rapidly than ever before. Some species are now impacted by development throughout their range. This has forced a re-evaluation of the potential of developed landscapes for providing habitat and contributing to regional conservation strategies. For many amphibians, little is known about the criteria necessary for persistence in a developed landscape. Considerable variation in the physiology, habitat requirements, and movement behaviour of amphibians suggests that responses to habitat loss, alteration, and fragmentation are species-specific. In this thesis, I investigate species-habitat relationships for the northern red-legged frog (Rana aurora) and the Pacific chorus frog (Pseudacris regilla) in a mixed urban-rural landscape in southwestern British Columbia to evaluate the potential for species persistence despite urban and rural development throughout their range. I used repeat auditory surveys of the species’ breeding chorus to determine presence or absence at potential breeding wetlands. I then related species occurrence and abundance to characteristics of the aquatic and terrestrial environment measured at multiple spatial scales. Both species were found to use rural and urban wetlands, though R. aurora were rarely detected while P. regilla were common. Occurrence was best explained by characteristics of the terrestrial environment, rather than within-wetland characteristics, though influential terrestrial characteristics and their scale of impact differed between species. Within the context of the developed landscape, I identify species-specific positive and negative habitat associations and suggest the spatial scales at which management of these habitat characteristics will be most effective. These criteria may help to explain the species’ current distribution, prioritize management strategies, predict the effectiveness of habitat conservation and restoration projects, and inform development in municipalities seeking to maintain or enhance amphibian diversity. / Graduate / 2019-09-11

Understanding how migration, genetic drift, and natural selection interact to maintain the genetic and phenotypic variation we observe in natural populations is a central goal of population genetics. Amphibians provide excellent model organisms for investigating the interplay between these evolutionary forces because amphibians are generally characterized by limited dispersal abilities, high philopatry, and are obligately associated with the areas around suitable habitats (e.g. breeding ponds). Thus, on relatively small geographic scales, the relative effects of all of these evolutionary forces can be studied together. Here, we study the interaction of migration, genetic drift, natural selection, and historical process in the ornate chorus frog (Pseudacris ornata). We report the development and characterization of 10 polymorphic microsatellite genetic markers. Number of alleles per locus ranged from 2 to 21 averaging 9.2 and expected heterozygosities ranged from 0.10 to 0.97 averaging 0.52. However, in an analysis of two populations, three locus-by-population comparisons exhibited significant heterozygote deficiencies and indicated that null alleles may be present some loci. Furthermore, we characterized genetic structure and historical biogeographic patterns in P. ornata using these microsatellite markers along with mitochondrial DNA sequence data. Our data indicate that in these frogs, migration may play a large role in determining population structure as pairwise estimates of FST were relatively small ranging from 0.04 to 0.12 (global FST = 0.083). Additionally, we observed an overall pattern of isolation-by-distance in neutral genetic markers across the species range. Moreover, our data suggest that the Apalachicola River basin does not impede gene flow in P. ornata as it does in many vertebrate taxa. Interestingly, we identified significant genetic structure between populations separated by only 6 km. However, this fine scale genetic structure was only present in the more urbanized of two widespread sampling localities. Finally, in this study, we demonstrated that there was a significant correlation between the frequency of green frogs and latitude. There was a higher frequency of green frogs in southern samples and a lower frequency of green frogs in northern samples. However, when we interpreted this phenotypic cline in light of the overall pattern of isolation-by-distance, it was apparent that the neutral evolutionary forces of genetic drift and migration could explain the cline, and the invocation of natural selection was not necessary.