Habitat alteration (i.e. degradation, fragmentation, and destruction) is the primary driver of amphibian decline and extinction. Despite their ecological importance and threatened status, very little long-term research has been conducted on how methods of forest management impact salamanders. In this research, I examine how experimental silviculture impacts plethodontid salamander relative abundance and count, and I compare three different body condition indices. Chapter 1 focuses on plethodontid salamander relative abundance 30 years after experimental treatments (including clearcut and shelterwood harvests, understory herbicide, uneven-aged management, and an untreated control) were first applied. I found that plethodontid salamander populations in all silvicultural treatments without stand re-entry have reached pre-harvest relative abundance levels. Chapter 2 describes how artificial tip-up mounds that could be used to mimic old-growth forest characteristics impact plethodontid salamander count. Salamander count significantly declined in treatment units with artificial tip-up mounds but this could be an artifact of the heavy disturbance required for installation. Chapter 3 compares three different body condition indices for plethodontid salamanders. I found that bioelectrical impedance analysis (BIA) is likely not suitable for use with plethodontid salamanders and mass divided by snout-to-vent-length is likely a superior estimate to tail width divided by snout-to-vent-length. These findings further our understanding of how different forest management practices affect salamander populations and provide guidance for evaluating body condition. / Master of Science / Forest understory salamanders play an important role in energy transfer and their position in leaf litter food webs affects multiple ecosystem functions. Despite their ecological importance, very little long-term research has been conducted on how habitat change impacts salamanders. This research investigates how different forest management techniques influence forest-dwelling salamanders and compares three different ways to evaluate salamander health. Chapter 1 focuses on the salamanders 30 years post-harvest. I found that salamander populations in all silvicultural treatments except one had recovered. Chapter 2 described how tipping over trees to mimic old-growth forest characteristics impacts the number of forest-dwelling salamanders. There were significantly fewer salamanders in treatment units after the disturbance created by installing artificial tip-up mounds. Chapter 3 compares three different ways to evaluate forest-dwelling salamander health. I found that bioelectrical impedance analysis (BIA)is likely not suitable for forest-dwelling salamanders, and weight divided by body length is likely a superior estimate to tail width divided by body length. These findings together further our understanding of how different forest management practices affect salamander populations and provide guidance for evaluating body condition.

Bruce Peninsula National Park (BPNP) clears a 2 m swath of trees on the boundary in order to make it clear when one is entering the park from any neighbouring land; this in particular aims to protect the park and its inhabitants from illegal actions such as hunting and logging. This study looks at the ecological effects of this practice by measuring various microclimate variables and the abundance of eastern redback salamanders (Plethodon cinereus) on the boundary and comparing these measurements to parallel transects at 5, 10, 15, 20, and 40 m. Because it is a small linear development, it is then compared to other types of linear developments, such as roads, trails, and pipelines. The microclimate variables of air temperature, slug abundance, canopy cover, soil pH, total cover area, litter depth, and relative humidity were all significantly affected (p<0.05) up to 10 m into the adjacent forest, indicating that the cleared boundaries do change the surrounding microclimate. Soil pH, downed woody cover area, litter depth, and canopy cover were significantly affected (p<0.05) up to 5 m away from the boundary. Sixty hectares, or 0.4%, of the land area of BPNP is thus affected by the microclimate changes caused by the cleared boundary. These effects are similar to those found for other narrow, vegetated linear developments such as trails. Over double the number of salamanders were found on the boundary as compared to in the forest; this is due to higher cover area availability on the cleared boundary from the felled trees. Therefore, the boundary does not act as a barrier to eastern redback salamander movement, nor does it fragment the local population. Salamander abundance was best explained by the amount of cover area, snail abundance, and the dominant type of vegetation present along transects. It was also found in an additional study that salamander abundance tended to increase with increasing days since the last precipitation event, contrary to most woodland salamander monitoring protocols and methods. The boundaries were seen also to be used by hunters and recreationalists through incidental observations of human disturbance. This increased access to remote areas of the park through use of the cleared boundaries is an issue that requires further study, as the boundary itself may be leading to an increase in illegal activity. Recommendations to BPNP include leaving downed woody cover on the boundary, minimizing the boundary width, reducing lines of sight, decreasing accessibility, increasing landowner and park staff education, communicating with adjacent landowners, and securing funding to complete and maintain the boundary clearing.

Bruce Peninsula National Park (BPNP) clears a 2 m swath of trees on the boundary in order to make it clear when one is entering the park from any neighbouring land; this in particular aims to protect the park and its inhabitants from illegal actions such as hunting and logging. This study looks at the ecological effects of this practice by measuring various microclimate variables and the abundance of eastern redback salamanders (Plethodon cinereus) on the boundary and comparing these measurements to parallel transects at 5, 10, 15, 20, and 40 m. Because it is a small linear development, it is then compared to other types of linear developments, such as roads, trails, and pipelines. The microclimate variables of air temperature, slug abundance, canopy cover, soil pH, total cover area, litter depth, and relative humidity were all significantly affected (p<0.05) up to 10 m into the adjacent forest, indicating that the cleared boundaries do change the surrounding microclimate. Soil pH, downed woody cover area, litter depth, and canopy cover were significantly affected (p<0.05) up to 5 m away from the boundary. Sixty hectares, or 0.4%, of the land area of BPNP is thus affected by the microclimate changes caused by the cleared boundary. These effects are similar to those found for other narrow, vegetated linear developments such as trails. Over double the number of salamanders were found on the boundary as compared to in the forest; this is due to higher cover area availability on the cleared boundary from the felled trees. Therefore, the boundary does not act as a barrier to eastern redback salamander movement, nor does it fragment the local population. Salamander abundance was best explained by the amount of cover area, snail abundance, and the dominant type of vegetation present along transects. It was also found in an additional study that salamander abundance tended to increase with increasing days since the last precipitation event, contrary to most woodland salamander monitoring protocols and methods. The boundaries were seen also to be used by hunters and recreationalists through incidental observations of human disturbance. This increased access to remote areas of the park through use of the cleared boundaries is an issue that requires further study, as the boundary itself may be leading to an increase in illegal activity. Recommendations to BPNP include leaving downed woody cover on the boundary, minimizing the boundary width, reducing lines of sight, decreasing accessibility, increasing landowner and park staff education, communicating with adjacent landowners, and securing funding to complete and maintain the boundary clearing.

No description available.

Behavioral fever is an essential coping mechanism across ectothermic phyla to aid in combating pathogenic threats. Ectotherms lack internal temperature regulation associated with fever in endotherms; thus, ectotherms can exhibit a behavioral fever response when immunocompromised to thermoregulate by moving to warmer locations. The salamander order Caudata, tend to be keystone species in their resident ecosystems through their role as secondary consumers of invertebrates to maintain the food chain. With growing interest about ecology and conservation of salamanders as species diversity declines, this study was designed to determine if salamanders use their environment to take advantage of behavioral fever. The lungless salamander, Plethodon glutinosus, was used to investigate behavioral fever through exposure to the synthetic viral pyrogen polyinosinic:polycytidylic acid (Poly (I:C)) at doses of 15 µg/g by live wet weight. After 24 hours, the induced fever specimens were placed in a linear temperature gradient with a controlled humidity of 95% throughout. Average temperature preferences were then monitored over a 12-hour period and resulted in control animals preferring cold and moderate temperatures between 15-19 °C while all poly (I:C) injected animals preferred higher temperatures from 19-21°C (p<<0.0001). This result supports that P. glutinous responds to immunocompromising threats such as presented by synthetic viral pyrogen Poly (I:C) through use of behavioral fever.

No description available.

Sexual selection can influence the mating system of an organism through multiple mechanisms. These mechanisms result in variation in reproductive success among individuals, and include scramble competition, endurance rivalries, contests, mate choice and cryptic choice, and sperm competition. Understanding the mating system of a species requires the identification of which processes are occurring, and to what degree. In this thesis, I explored the influence of mate choice mechanisms on the mating system of the terrestrial red-legged salamander, Plethodon shermani. I also documented the potential for post-copulatory processes (such as sperm competition and cryptic choice) to influence mating system dynamics. The evolution of mate choice requires (among other factors) variation in the reproductive value of potential mates. This variation is made apparent to choosy individuals through cues. Most animals use multiples cues incorporating many modalities to assess the reproductive quality of potential mates. In Chapter 2, I tested the contribution of two cues (chemical and visual) to mate choice by female P. shermani. I found that a male visual cue ("foot-dancing") increased courtship success. In contrast, delivery of non-volatile pheromones during courtship did not influence courtship success in the laboratory setting, but did affect the duration of one of the courtship stages. In Chapter 4, I identified a tactile cue that was significantly correlated with male reproductive success. Thus, P. shermani females could use at least three modalities to assess the reproductive quality of potential mates. Mate choice can also evolve in males. In Chapter 3, I tested this possibility in P. shermani. I found that males vary the reproductive effort they invest in a particular courtship based on the reproductive value of their partner, indicating male mate choice is occurring. A male invested most when paired with a female with large, well developed ova, and invested less with females that were non-gravid or had small ova. In addition to documenting male mate choice, I showed that the male visual display ("foot-dancing") that affected female mate choice was correlated with male condition, implying foot-dancing may be an honest indicator of male quality. Finally, in Chapter 5, I explored the potential for post-copulatory processes to influence the P. shermani mating system. The opportunity for sperm from multiple males to overlap in the female reproductive tract (i.e., the opportunity for females to mate multiply) is necessary for post-copulatory processes such as cryptic choice and sperm competition. The capacity for long-term sperm storage by females can increase the likelihood that this overlap in sperm from multiple males will occur. I found that females can store viable sperm for at least 9 months and in some cases beyond oviposition. In addition, I documented one female with sperm in her sperm storage organ from a mating that occurred 17 months earlier. Such lengthy sperm storage allows the possibility of sperm from one breeding season to interact with sperm from a subsequent season. Thus, the potential for post-copulatory sexual selection within this salamander system is high. / Graduation date: 2012

Habitat fragmentation can influence the genetics of a population through the direct loss of genetic diversity, and by the genetic processes that occur as a result of small remnant populations or the geographic isolation of populations. I examined the population genetics of two woodland amphibian species in localities with different land-use histories. The wood frog (Rana sylvatica) and the red-backed salamander (Plethodon cinereus) use the same general habitat but differ with respect to a few key life-history characteristics relating to dispersal. I then compared between species the relative influence each land-use scenario had on the population genetic structure. I found that habitat fragmentation affected the population genetics of the two amphibians and did so differently for each species. The differential population genetic response of these two amphibians to habitat fragmentation reinforces the important role of life-history characteristics in how the genetic structure of a population is shaped over time.

No description available.

No description available.