Within managed pine forest systems, a plethora of bird species exist throughout the lifecycle of a stand akin to what may be experienced through post-disturbance regeneration in a natural forest system. I sought to address how breeding avian communities shift across time in response to stand aging and forest management, evaluate species-specific responses to stand conditions, investigate the responses of at-risk avian species to forest management, and determine avian non-breeding, over-wintering presence in a managed loblolly pine (Pinus taeda) forest. I conducted breeding bird point count and vegetation surveys within five stands of privately owned and managed pine forest in Mississippi, each of which was split into quadrants with different management strategies implemented. I designed and executed night surveys for Chuck-will’s-widow (Antrostomus carolinensis). Lastly, I conducted winter bird banding to explore over-wintering diversity, dietary isotope assimilation, and parasite prevalence. I found evidence that the avian community shifted in response to forest stage and structure, with differences created by management practices and forest succession. Switchgrass (Panicum virgatum) intercropping allowed some grassland and early successional species to remain in forest stands with closing canopies longer than in plots with standard management, with few diversity differences between treatments. Abundance of Chuck-will’s-widow was found to relate positively with the percent cover of early successional forest stands, those which were recently harvested and replanted and were in a pine-grassland state. Over-wintering bird species richness remained relatively low, and capture rates were consistently greatest in a young open canopy stand, which contained a higher level of vegetation structure and plant abundance when compared to three older stands. This represents a limited number of studies where investigations into bird community responses to forest management took place in the same forest stands across a long temporal period. Managers in forest systems should consider the implications of management undertaken at different stages in the rotational lifetime of a forest stand. To focus on conservation of priority bird species, managers should increase heterogeneity by maintaining or creating pine-grassland and early successional forest conditions within forest stands while also ensuring stands of various ages exist concurrently within the forest ecosystem.

There is an increasing interest in the use of autonomous recording units as an alternative survey method to point count surveys conducted by human observers; however, questions remain about whether or not these recording units perform similarly to point count surveys and produce valid, comparable results. The use of individual listeners to transcribe the acoustic data collected by autonomous recording units is a common method for the analysis of recorded acoustic data, but potential variability among transcribers raises questions about the standardization of listening protocols to decrease inconsistencies in transcription results. Autonomous recording units have been used to monitor birds in and around Brimfield State Forest in Brimfield, Massachusetts since 2012, after a tornado severely damaged a large area of the forest and surrounding properties. In 2016 and 2017, I conducted 71 10-minute point count surveys while simultaneously recording the survey with an autonomous recording unit in three habitat types in and around Brimfield State Forest in Brimfield, Massachusetts. I transcribed the acoustic data from the recordings and compared it to the results of the point count surveys to determine if autonomous recording units performed as well as point count surveys. To assess variability among listeners, four listeners transcribed the same sample of 30 recordings and a sub-sample of 6 of those recordings that were created during the 2014 field season using two different listening protocols. The first protocol instructed listeners to play each recording straight through without stopping, and the second protocol instructed listeners to stop and replay any part of the recording they needed to and also use outside sources to aid in species identification. I compared the number of species, individuals, distant individuals, and mean counts (uncorrected abundance), corrected abundance and detectability of focal species between both survey methods, among all listeners using both listening protocols, and where possible between habitat types to assess differences in method performance and listener variability. I tested for correlation between autonomous recording units and point counts using the uncorrected and corrected abundance estimates. The number of species and number of individuals detected did not differ between survey methods overall and for each habitat individually; however, in each habitat type, more individuals were classified as distant by autonomous recording units overall for all habitats. The number of species detected did not differ between listeners overall and for in each habitat using either listening protocol. The number of individuals and distant individuals detected differed significantly between listeners and within certain habitats using the first listening protocol. There were no differences in the number of species, individuals, or distant individuals detected overall between listeners using the second listening protocol, but there were significant differences in individuals and distant individuals detected between habitats by listeners. Corrected and uncorrected abundance estimates between autonomous recording units and point count surveys were highly correlated, and there were no differences in detection probabilities for the focal 23 species between survey methods and among habitat types. Only 2 out of 18 focal species indicated a significant difference in detection probability between listeners using both listening protocols. Based on the results of my study, I conclude that autonomous recording units perform at least as well as human observers conducting point count surveys, and that multiple listeners transcribing the same acoustic data do not show high levels of variation in the results of their transcriptions.

Myers first identified the world’s 25 biodiversity hotspots and pioneered innovative ideas about the usefulness of biodiversity models for establishing long-term resource conservation strategies at global scales. Since Myers, most of the subsequent studies using hotspot science for biodiversity modeling have used large spatial scales like countries, provinces or states, and other biogeoraphic regions. The California Floristic Province continues to be one of the recognized global biodiversity hotspots. Our study site, San Luis Obispo County is within this hotspot and we created a map of plant biodiversity hotspots at the county scale using GIS technology. We wanted to determine the effectiveness and applicability of biodiversity hotspot mapping at this scale with anticipation that the map will serve as a new tool for establishing long-term resource conservation strategies in the County. Our plant biodiversity hotspot map is based on distribution data collected from herbarium specimens of San Luis Obispo County’s rare flora. These data were extracted from the Hoover Herbarium at Cal Poly and manually digitized into GIS. We built a model with GIS to identify, locate, and quantify the resultant hotspots from the data. The overall approach was successful at identifying and quantifying the attributes and geographic extents of plant biodiversity hotspots at the county scale. Our results are highly applicable for establishing local and regional plant conservation priorities at lower resolutions, which is frequently where land acquisition and reserve establishment occurs. We conclude that biodiversity hotspot modeling with GIS is an effective tool that can be applied to many other finer-scale biological inventories for conservation purposes.

This thesis is composed of two chapters. Chapter one reviews what is known about adaptive plasticity in response to predators, describes the physiological systems involved in such plasticity, and outlines the evolutionary consequences of adaptive plasticity. Chapter two describes a scientific experiment that investigates how malathion may impact adaptive plasticity in the Sierran Treefrog, Pseudacris sierra. Anuran tadpoles suffer high mortality rates due to predation. In response to strong selective forces relating to these high predation rates, tadpoles evolved the ability to adaptively respond to predators through morphological and behavioral plasticity. The morphological and behavioral responses are varied and depend on the hunting strategy of the predator, and the adaptive responses may be influenced by other biotic and abiotic factors. Tadpoles detect alarm cues released from tadpoles being eaten and kairomones that are released by predators. Tadpoles respond to these signals by changing tail and body shape along with a reduction of activity level, which enables tadpoles to escape predators more effectively. These changes in morphology can occur within a week, and behavioral changes can occur within 15 minutes. The adaptive responses are critical for increasing survival rates of tadpoles to metamorphosis and may have important evolutionary consequences for anurans. Amphibians are in decline worldwide, and pollutants are considered to be a major contributor to these declines. Every year 5.2 billion pounds of active ingredients of pesticides are applied worldwide, and these application rates have led to ubiquitous low-level contamination of aquatic ecosystems. How low-level contamination of pesticides directly and indirectly affect how tadpoles respond to their predators is poorly understood. One potential indirect effect of pesticides is the inhibition of adaptive plasticity. Pesticides have been shown to modulate corticosterone levels in tadpoles. Corticosterone is the most likely mediator of the physiological response that results in adaptive morphological change. If the physiological system of tadpoles relies on corticosterone as the mediator of adaptive response, and pesticides can modulate corticosteone levels, then pesticides may inhibit or negatively impact adaptive responses to important biotic factors, like predators. Pesticides have been shown to weaken immune systems, affect developmental and physiological pathways that lead to malformations, and cause direct mortality in anurans. Little research has investigated the effect of pesticides on adaptive morphological and behavioral plasticity in response to predators. Adaptive phenotypic responses to predators increase survival rates to metamorphosis and are important in stabilizing amphibian populations through time. If pesticides influence the ecological interactions of tadpoles and their predators, this could play a part in amphibian declines. In the experiment explained in Chapter two, I tested the hypothesis that malathion at a concentration of 0.1 mg/L inhibits anti-predator morphological and behavioral responses of Pseudacris sierra to the predatory dragonfly larvae Anax junius. The results of this experiment show that malathion alone caused the tail muscle depth to increase to the same magnitude as tadpoles that only experienced a predator’s presence. Malathion also caused a significant increase in tail depth, demonstrating that malathion directly causes morphological change. The experiment did not support the hypothesis that malathion inhibits adaptive plasticity, and malathion had no impact on behavioral plasticity. The results from this experiment give evidence that an ecologically relevant concentration of malathion can influence morphological components that are critical in escaping depredation events, which could affect predator-prey interactions.

Reproductive barriers are vital to generating new species as well as maintaining distinct species. Investigating reproductive barriers between closely related plant taxa helps us to understand how these barriers are maintained, particularly between rare and widespread relatives. Layia jonesii, a rare San Luis Obispo County serpentine endemic, and L. platyglossa, a common coastal species, co-occur on serpentine derived hillsides and are interfertile. At these locations, L. jonesii is isolated to dry soils near serpentine rock outcrops and L. platyglossa is located on slightly deeper grassland soils surrounding the rock outcrops. On hillsides where they co-occur, I observe two morphologically distinct species, therefore the two species must be maintaining reproductive barriers, yet mechanisms that maintain this isolation are unknown. I studied this system to investigate possible mechanisms contributing to the maintenance of reproductive barriers. I hypothesize prezygotic reproductive isolation in this system is due to (1) habitat isolation due to local adaptation to differential edaphic environments on the hillside, (2) flowering time differences, and (3) reduced seed set resulting from hybrid crosses. To investigate the local adaptation of L. jonesii and L. platyglossa, I reciprocally transplanted both species into the center of each species’ distribution. I also conducted a competition experiment to determine if L. jonesii is sensitive to resource competition beyond its natural distribution. To investigate flowering time differences, I tracked flowering time of both wild and reciprocally transplanted populations. I also performed controlled crosses to determine if heterospecific, or hybrid crosses, result in lowered seed set than conspecific crosses. The reciprocal transplants showed L. platyglossa is locally adapted to the grassland habitat. Local adaptation likely prevents L. playtyglossa from dispersing into the rock outcrop habitat. Results of the competition experiment revealed L. jonesii is sensitive to competition and this may contribute to its constrained distribution to shallow soils. Local adaptation and competition likely contribute to habitat isolation between the two species. I also documented stark differences in flowering time between the species which contributes to reproductive isolation by reducing pollen flow. Hybrid crosses also resulted in lowered seed set than conspecific crosses. These results suggest prezygotic barriers to reproduction likely maintain the majority of isolation between the two species. These results provide insight into mechanisms that maintain reproductive barriers between closely related taxa existing in similar habitats. The results also contribute to our understanding of how rare plants preserve genetic integrity near common and interfertile relatives.

In the Arctic, brown algae (kelps) and seaweeds are ecologically important: providing habitat, protection, and nutrients for invertebrate and vertebrate species living in nearshore environments. Migrations of biota between the North Pacific and North Atlantic Oceans have occurred periodically during Earth’s history leading to colonization of the Arctic Ocean. Around 3.5 Mya the “Great Trans-Arctic Biotic Interchange” occurred and the Laminariales order of kelp, thought to be of North Pacific origin, underwent a massive radiation and speciation event around the Arctic Ocean. Phylogenetic analysis performed on “Laminaria-like” specimens collected from six sampling locations around the Svalbard Archipelago identified both the presence of Saccharina groenlandica and Laminaria digitata. This research represents new records for the presence of S. groenlandica around the Svalbard Archipelago. S. groenlandica and L. digitata exhibit phenotypic similarities such that these two species can be difficult to tell apart in the field. In this study we have shown that the COI gene region can be used for DNA barcoding and can provide species level resolution between these two cryptic species. Prior to this study and Lund (2014), a number of biodiversity studies conducted around the Svalbard Archipelago identified the presence of L. digitata in a number of locations around the archipelago, however S. groenlandica was not identified in any of these prior studies. Phylogenetic analysis conducted here showed that all Svalbard specimens of S. groenlandica had identical COI sequences and up to 0.30% sequence diversity with S. groenlandica specimens from other parts of the Arctic Ocean. Further analysis is needed to understand the abundance of this newly recorded species around the archipelago and to investigate both the timing of arrival and mechanisms of colonization.

Kangaroo rats (Dipodomys spp.) are frequently characterized as keystone species for their role in altering soil characteristics, changing habitat structure through seed consumption and dispersal, and being important primary consumers in their ecosystem. They are arid adapted and known to forage in areas with sparse vegetation. Studies suggests densely vegetated habitat to be unsuitable for kangaroo rats because plants are an impediment to their locomotion and predator avoidance behaviors. This study focuses on an invasive grass, South African Veldt (Ehrharta calycina), that converts landscapes with sparse vegetation into dense grassland habitats, and the Lompoc kangaroo rat (Dipodomys heermanni arenae) that occupies some of those modified landscapes. I explored the proximate effects of Veldt grass by assessing the locomotion of D.h. arenae in three Veldt grass densities. I hypothesized that Veldt grass influences kangaroo rat locomotion, but that performance could also be influenced by experience with the grass. Kangaroo rats with long-term experience with Veldt grass (i.e., those occupying a habitat containing Veldt grass) and short-term experience (two-night habituation in an artificial Veldt grass patch) were tested by pursing the animals through runways of different grass densities and measuring the amount of time spent crossing the runway, amount of time spent stopped, average velocity, and amount of motivation required to initiate and sustain movement. I also monitored habitat use during the two-night habituation period in order to assess habitat utilization among three Veldt grass density habitat patches. I hypothesized that Veldt grass may influence normal habitat utilization patterns in D.h. arenae: specifically, the avoidance of the densest habitats and preference or disproportionate utilization of the most open habitat. I found, when the animals were left alone to forage and explore, they spent significantly more time in habitat patches containing Veldt grass than in a control patch containing zero percent cover. However, in locomotion trials, Veldt grass had a negative effect on locomotory performance. These effects seem to scale with grass density, and were ameliorated to some degree by familiarization: animals from a Veldt grass habitat of origin performed better in novel Veldt grass templates than animals from a non-Veldt habitat of origin; however, both groups performed equally well after two nights’ habituation to the templates. These results suggest that learning occurred in two nights and that it increased the kangaroo rats’ ability to locomote through the grass when pursued. I note that performance studies often do not take into account the amount of motivation employed to initiate and sustain running of the test animals, and suggest that this be considered in future studies. Furthermore, the learning capacity of a kangaroo rat, as well as a community level perspective that considers neutral or even positive trophic interactions among natives and invasives, must be considered in conservation and management decisions in the future.

Sensory pollutants such as anthropogenic noise and night lighting now expose much of the world to evolutionarily novel sound and night lighting conditions, which can have detrimental effects on humans and wildlife. In my first chapter, we exposed wild Western Bluebird (Sialia mexicana) nestlings to noise, light, and combination (i.e., noise and light) treatments. Nests exposed to noise and light together experienced less predation than control and light-exposed nests, and noise-exposed nests experienced less predation than control nests, yet overall nest success was only higher in noise-exposed nests compared to light-exposed nests. Although exposure to light decreased nestling body condition and evidence was mixed for the singular effects of noise or light on nestling size, those exposed to noise and light together were smaller across several metrics than nestlings in control nests. Our results support previous research on the singular effects of either stimuli, including potential benefits, such as reduced nest predation with noise exposure. However, our results also suggest that noise and light together can negatively affect some aspects of reproduction more strongly than either sensory pollutant alone. This finding is especially important given that these stimuli tend to covary and are projected to increase dramatically in the next several decades. In my second chapter, we used a field-based manipulation to explore the role of audition in biodiversity perception and self-reported well-being of hikers. We used a “phantom chorus” consisting of hidden speakers playing bird vocalizations to experimentally increase audible birdsong biodiversity during “on” and “off” blocks on two hiking trails and surveyed hikers to record their self-reported perceptions of avian biodiversity and concepts reflective of attention restoration. We found that hikers exposed to the phantom chorus reported higher levels of restorative effects compared to those that experienced ambient conditions on both trails, although the causal relationships differed for each trail. Specifically, increased restorative effects were directly linked to the phantom chorus on one trail and indirectly linked to the phantom chorus on the other trail through perceptions of avian biodiversity. Our findings add to a growing body of evidence linking mental health improvements to nature experiences and, via our field-based manipulation, we identified audition as an important modality by which natural environments confer well-being. Finally, our results suggest that maintaining or improving natural soundscapes within protected areas may be an important component to maximizing human experiences, especially as tourism and noise pollution in protected areas grow.

Chapter 1: Animals can respond to extreme climate by behaviorally avoiding it, or by physiologically coping with it. We understand behavioral thermoregulation and physiological thermal tolerances, but water balance has largely been neglected. Climate change includes both global warming and changes in precipitation regimes, so improving our understanding of organismal water balance is increasingly urgent. We assessed the hydric physiology of endangered Blunt-nosed Leopard Lizards (Gambelia sila) by measuring cutaneous evaporative water loss (CEWL), plasma osmolality, body mass, and body condition throughout their active season. On average, G. sila had low CEWL that is likely desert-adaptive, and high plasma osmolality that is indicative of dehydration. Given that our study was in a drought year, it is reasonable to believe that every lizard measured was dehydrated to a degree. We hypothesized that throughout the G. sila active season, as their habitat got hotter and drier, G. sila would become increasingly dehydrated and watertight. Instead, CEWL and plasma osmolality showed minimal change for females and nonlinear change for males, which we hypothesize is connected to sex-specific reproductive behaviors and changes in food availability. We also measured thermoregulation and microhabitat use, expecting that more hydrated lizards would have higher body temperature, better thermoregulatory accuracy, and spend more time aboveground. However, we found no effect of CEWL, plasma osmolality, body mass, or body condition on these thermal and behavioral metrics. We posit either that G. sila tolerate dehydration to maintain activity during their brief active season, or that because every lizard was dehydrated due to the drought, they all experienced equally constrained thermoregulation and microhabitat use. Finally, G. sila spend considerable time underground in burrows, and we believe burrows serve as essential hydric, not only thermal, refugia. Our findings suggest that these lizards might benefit from artificial humid refugia and supplemental hydration, especially during drought. Chapter 2: Testing acclimation plasticity informs our understanding of functional biodiversity and applies to conservation management amidst our rapidly changing climate. While there is a wealth of research on the plasticity of thermal and hydric physiology in response to temperature acclimation, there is a comparative gap for research on acclimation to different hydric regimes, as well as the interaction between water and temperature. We sought to fill this gap by acclimating Western Fence Lizards (Sceloporus occidentalis) to experimental climate conditions (crossed design of Hot or Cool, Dry or Humid) for eight days, and measuring cutaneous evaporative water loss (CEWL), plasma osmolality, hematocrit, and body condition before and after acclimation under common conditions. CEWL changed plastically in response to the different climates, with lizards acclimated to Hot Humid conditions experiencing the greatest increase in CEWL. Change in CEWL among individuals was negatively related to treatment vapor pressure deficit. Plasma osmolality, hematocrit, and body condition all showed greater changes in response to temperature than to humidity or vapor pressure deficit. CEWL and plasma osmolality were positively related across treatment groups before acclimation and within treatment groups after acclimation, but the two variables showed different responses to acclimation, suggesting that they are interrelated but governed by different mechanisms. This study is among just a small number of studies that assess more than one metric of hydric physiology and that test the interactive effects of temperature and humidity. Such measurements will be essential for predictive models of activity and survival for animals under climate change.

This project used molecular genetic markers (microsatellites) to determine the amount of genetic diversity within populations and whether significant differentiation exists among Florida populations of the long-spined sea urchin, Diadema antillarum. Specifically, this project aimed to (1) compare genetic diversity of D. antillarum from six populations in south Florida ranging from Biscayne Bay, the Florida Keys, and Dry Tortugas, and (2) determine whether two broodstock populations of D. antillarum contain variation indicative of native Florida populations. Together, these questions can address whether broodstock populations contain the genetic variation necessary to meet the Florida Fish and Wildlife Conservation Commission’s (FWC’s) genetic policies for reintroduction throughout south Florida. Global FST among native populations was 0.0004 with a highest pairwise FST of 0.0025 between the Upper Keys and the area west of Key West, showing an overall trend of little natural differentiation between populations. Global FST for all populations inclusive of the broodstock samples was 0.0019 with a highest pairwise FST between a native population and broodstock of 0.0066 between Dry Tortuga and Mote’s broodstock, indicating little differentiation resulting from captive breeding. Average allelic richness and heterozygosity ranged from 22.6–24.4 and 0.937–0.956, respectively, for each population. Two-way ANOVAs comparing genetic diversity between native and broodstock populations showed no statistical difference in allelic richness (F= 3.892, p= 0.0535) or heterozygosity (F=1.43, p=0.237). The computer program STRUCTURE estimated the most likely number of genetic clusters to be k=1, inclusive of broodstock populations, further indicating a lack of differentiation either among native populations or between native and broodstock populations. These data suggest that captive-bred individuals of D. antillarum could be used for reintroduction as part of a plan to re-establish healthy urchin populations throughout the Florida Keys.