Vernal pools are often defined as seasonal pools that typically are inundated beginning in the winter and then drying out completely in summer. Though evidence of spatial and temporal variability in the macroinvertebrate communities of vernal pools has been found in previous studies, it has not been studied extensively. The primary objective of this study was to determine the extent of variability in the macroinvertebrate communities within vernal pools closely situated in a forested landscape. An effort was made to explain this variability with respect to certain physiochemical environmental variables of the pools. Significant variability was observed in the macroinvertebrate communities within the vernal pools both spatially and temporally. Water temperature, as an indicator of seasonal changes, was strongly correlated with the observed variations. Higher species richness and diversity were observed in the pools in winter than in spring 2007. Chironomidae was the most diverse family (8 genera) occurring in these vernal pools. At the beginning of inundation, amphipods and copepods were more abundant. β-diversity was low in both winter and spring 2007; α-diversity in winter was high and low in spring 2007.

Thesis advisor: Heather C. Olins / This study creates a protocol to investigate microplastics in local freshwater wetlands surrounding Boston College. This study also investigated potential plastic-degrading bacteria in the sediment of local freshwater wetlands. A list of potential plastic-degrading bacterial species and genera were compiled from the literature. Using these compiled lists, we searched for these potential plastic-degrading organisms in our metagenomics and 16S datasets. Looking for potential correlations between abiotic factors and the abundance of potential plastic-degrading bacteria, for both data sets, it was found that sandy sediment had a higher abundance of potential plastic-degrading bacteria than non-sandy sediment. Finally, our list of plastic-degrading bacterial species was cross-referenced with a previously compiled list of potential pathogens. Of the 26 taxa in our sites that were identified as potential plastic-degrading bacteria, 57.69% of those taxa are also potentially pathogenic to humans. / Thesis (BS) — Boston College, 2020. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: Departmental Honors. / Discipline: Earth and Environmental Sciences.

Recently the uniqueness of the vernal pool habitat has been recognized by several groups of biologists. A survey of the literature reveals that interest of botanists, but one notes a lack of information of plankton which are so fundamental in the food web. Therefore, a taxonomic survey of the plankton seems appropriate. In the present study, the abundance of the predominant species of plankton were studied during a seasonal and also diurnal cycle. A possible correlation of this information with some physicochemical factors was also tested. Because of time constraints this study was limited to one pool but hopefully other researchers will extend this work in the future.

Aquatic habitats are closely linked to surrounding terrestrial environments via reciprocal subsidies. Much of the research on these subsidies has been focused on streams, while subsidies across aquatic-terrestrial boundaries of other aquatic systems, like temporary ponds, have received little attention. Temporary ponds are seasonally inundated aquatic habitats and patterns of energy transport across transient aquatic-terrestrial boundaries are not well understood. To address the lack of information regarding these cross-habitat subsidies, I quantified: 1) leaf litter inputs, 2) amphibian egg inputs, 3) terrestrial insect inputs, 4) amphibian metamorph emergence, and 5) aquatic insect emergence for eight temporary ponds. Terrestrial insect inputs to ponds represented substantial high-quality subsidies to ponds that are generally unaccounted for in similar studies. While larger ponds produced greater total fluxes to terrestrial habitats, smaller ponds were often more productive per unit area. Therefore, a mosaic of small ponds may produce greater or equivalent subsidies and may be of greater value to terrestrial food webs than a single large pond. Resource subsidies of energy and nutrients can be transported via physical forces or biotic processes, such as animal migration or emigration. I quantified net nutrient fluxes associated with amphibian migrations across aquatic-terrestrial boundaries of eight temporary ponds in Illinois. I measured carbon (C), nitrogen (N), and phosphorus (P) subsidies from forests to ponds, in the form of eggs, and the reciprocal subsidies from ponds to forests via juvenile emigration. Juvenile emergence biomass did not resemble egg biomass, as not all species bred successfully in each pond, resulting in variability in the magnitude of nutrient fluxes both across ponds and species. The forest was not always the recipient system of net nutrient fluxes. Hydroperiod, trophic interactions, and species composition explained some dynamics of N and P subsidies. Most studies have focused on the magnitude of cross-boundary fluxes, but the impact of a subsidy is mediated by the size of the flux as well as the quality and relative abundance of similar resources in the recipient habitat. Long-chain polyunsaturated fatty acids (LC-PUFAs) are necessary for proper physiological function, are unevenly distributed across the landscape, and animals differ greatly in their ability to synthesize them de novo. This creates the potential for limitation and increases their possible importance as a subsidy. I examined LC-PUFA tissue concentration and export in eight species of emerging amphibian metamorphs across eight temporary ponds in a wetland complex. I found that tissue concentrations and export of LC-PUFAs varied across species, but were generally within the ranges of several freshwater fish and aquatic insects. Anurans exported higher amounts of LC-PUFAs than salamanders, largely due to the higher emergence biomass of anurans. Further, I explored fatty acid profiles and immune function of wolf spiders in wetland and upland habitats. Wetland spiders had higher tissue levels of aquatic-derived LC-PUFAs and elevated immune function compared to upland spiders. These patterns suggest aquatically derived nutrients, such as LC-PUFAs, may benefit organisms exploiting freshwater habitats.

Much of the world’s aquatic food webs and nutritional relationships have been blurred by the ever-increasing evidence that many phytoplankton are not exclusively heterotrophic or autotrophic, but instead mixotrophic. Mixotrophy is a continuum of different energy and carbon-acquisition mechanisms utilizing both autotrophy and heterotrophy which distorts the concept of single trophic tier modality. This makes mixotrophs flexible to adapt to environmental pressures and is becoming more the rule than the exception in many aquatic ecosystems. One unique environmental setting where mixotrophy could be highly beneficial to food web stability is in seasonally occurring ephemeral pools – aka vernal pools. Mid-Atlantic vernal pools are biodiverse biogeochemical hotspots and critical breeding habitats for a diverse number of endemic taxa including many endangered amphibian species. Vernal pools are not permanent standing bodies of water and have fluxes in hydrology, temperatures, nutrients, and irradiance to name a few. These extremes make vernal pools an ideal setting for mixotrophic phytoplankton, however it’s never been investigated. Our survey found mixotrophy in every vernal pool sampled, as well as elevated grazing rates in pools experiencing nontypical seasonal conditions. From these small-scale forest pools to the world’s oceans mixotrophy is a widespread nutritional strategy. The Southern Ocean is essential for powering worldwide ocean circulation, regional biogeochemical cycles, and global climate. One of the major hurdles with understanding mixotrophy is identifying the phytoplankton capable of shifting nutritional strategies. While many Southern Ocean plankters have been properly identified as mixotrophic, one such keystone species has gone mislabeled until now. Phaeocystis antarctica is a well-studied Haptophyte algae that plays major roles in the global carbon and sulfur cycles. This species has been historically labeled as an obligate phototroph, but contradictory survives the long dark Antarctic winter without any known evidence of encystment. We suspect that this highly abundant species is in fact mixotrophic, capable of phagocytosis to supplement the irradiance shortcomings of the Antarctic dark. We experimented with varying degrees of light and nutrient limitations to determine possible triggers for P. antarctica grazing. Our results showed P. antarctica ingesting in every treatment, but its highest grazing rates corresponded with limitations to its primary photosynthetic mode. Apart from the newly realized complexity P. antarctica brings to the Southern Ocean food web, it is an environment that suffers from microplastic pollution that can impede these mixotrophic species. Mismanaged plastic waste around the world, especially microfiber discharge from laundered synthetic textiles, escape into the natural environment, and eventually concentrate in the oceans. The Southern Ocean can become disproportionately polluted in regions due to microfibers becoming sequestered once crossing the Antarctic circumpolar current and even becoming trapped in sea-ice formations. While it is easy to see the devastation plastic waste has on megafauna (i.e. turtles, fish, birds, and whales), its microscopic devastation is less obvious. Plastic waste comes in many forms and one less researched form is buoyant polyester microfibers <1mm that interact with colony forming algae. We utilized different concentrations of polyester microfibers and mixing speeds to determine if microfiber interactions with colony formations increases or decreases overall colony buoyancy. Smaller concentrations of polyester microfibers can impart a positively buoyant effect onto P. antarctica colonies regardless of mixing speed, however larger concentrations negatively affected colony buoyancy regardless of mixing speed. / Biology

In the Southern Appalachians, there are growing concerns about Spotted Salamanders (Ambystoma maculatum) due to habitat destruction and the uncertain future of their forested riparian habitat. In this study, I establish baseline data of a population of Spotted Salamanders so future monitoring of this population can be performed. The study site is located in northeastern Tennessee, just east of the city of Bristol. It is a vernal pond at the Osceola Island Recreation Area one mile below the South Holston Dam on Holston View Dam road. A drift fence was established completely around the perimeter of the vernal pond to capture Spotted Salamanders entering and exiting the study pond. Individual Spotted Salamanders were identified using spot pattern recognition. An estimated population size of 2,449 Spotted Salamanders was determined to utilized the pond for breeding for the spring of 2003.

Mole salamanders (Ambystoma) and woodfrogs (Lithobates sylvaticus) are abundant in New England and depend on ephemeral wetlands for breeding. Their aquatic habitats have been well studied and are protected by several local and regional regulations. State endangered species laws also protect mabled salamanders (A. opacum), Jefferson salamanders (A. jeffersonianum), and blue-spotted salamanders (A. laterale). However, these amphbibians spend most of their adult lives in terrestrial habitats that remain poorly protected and elusive to researchers. In chapter 1, I developed a novel technique using passive integrated transponders for tracking small animals. I used this technique to track marbled salamanders walking up to 200 m from their breeding pond during post-breeding migrations. In Chapter 2, I examined the importance of multiple habitat variables for predicting the distributions of woodfrogs and spotted salamanders at 455 ponds in western Massachusetts. Based on a variable-comparison technique I developed, the best predictor for either species of amphibian was the amount of forest in the surrounding vii landscape. Both species were found more frequently in upland forests where the ponds are least protected by state and federal wetland regulations. In chapter 3, I used my data from chapter 2 and three other similar data sets to conduct an analysis of spatial scale and to parameterize a recently published resistant kernel model. The complex model parameterized by an expert panel did significantly worse than the null model. The distributions of both amphibians were best predicted by measuring the landscape at very large scales (over 1000 m). The most effective scales for conservation may be largest for organisms of intermediate dispersal capability. In chapter 4, I explored the evolution and genetics of the Jefferson/blue-spotted/unisexual salamander complex. I framed research into the fascinating unisexual reproductive system with a model that relates nuclear genome replacement, positive selection on hybrids, and biogeography of the species complex. I parameterized this model using genetic data taken from salamanders spanning Massachusetts and an individual-based breeding simulation. If paternal genomes are transmitted to offspring with the frequencies reported from laboratory experiments, then my model suggests that there must be strong selection favoring unisexuals with hybrid nuclei.

Vernal pools are essential breeding habitat for amphibians - the vertebrates most at-risk across the globe. Unfortunately, due to their small sizes and temporary nature, vernal pools are prone to indiscriminate destruction. This is the case in southern Ontario as most vernal pools have already been destroyed by human development. As such there is an urgent need to map remaining vernal pools in relatively undeveloped forested regions, such as the District Municipality of Muskoka in South-Central Ontario. This thesis aims to head-start the creation of a community-based vernal pool mapping project using LiDAR in South-Central Ontario. This goal has been broken down into two chapters with their own sub-objectives. In one chapter, we implemented a pilot study for integrating community involvement in potential vernal pool mapping across the Muskoka River Watershed (i.e., the major watershed of the District of Muskoka). We built a protocol and survey based on past vernal pool projects and studies which effectively integrated citizen involvement and also implemented novel online components (e.g., a portal) for vernal pool field-work. Our efforts were successful with positive feedback for the online components and a majority of the potential vernal pools located by our volunteers were probable vernal pools. In the other chapter, we developed two potential vernal pool mapping protocols using LiDAR based on regional characteristics of pools across the District of Muskoka in the Muskoka River Watershed and Coastal Georgian Bay. We demonstrated that the best mapping protocol for each of the two regions were associated with the protocol that was based on their respective pool characteristics. Moreover, we determined that while LiDAR can increase the accuracy of vernal pool mapping efforts, this is not always the case, especially when mapping vernal pools that occur in expansive bedrock laden regions. / Thesis / Master of Science (MSc) / Vernal pools, small forested temporary wetlands, provide essential breeding habitat for amphibians - the most threatened vertebrate group across earth. Unfortunately, most vernal pools in southern Ontario have been destroyed by human development, and there is an urgent need to map remaining vernal pools in relatively undeveloped forested regions, such as the District Municipality of Muskoka in South-Central Ontario. We implemented a pilot study for integrating community involvement in potential vernal pool mapping and developed two potential vernal pool mapping protocols using LiDAR based on regional pool characteristics. With successful integration of volunteers and mapping accuracies above 80%, we hope our findings will aid future vernal pool conservation, especially by head-starting the creation of a community-based vernal pool mapping project using LiDAR in South-Central Ontario.

No description available.

Zugl.: Freiburg (Breisgau), Univ., Diss.