Moose (Alces alces) have been re-established in much of the historic range in the northeastern United States. Recently the southern edge of the species ranges has been extended southward into southern New England and northern New York from established populations in northern New England. The southern expansion raised questions as to the ability of this northern species to cope with higher temperatures, areas densely populated by humans, and different forest types further south. In light of these recent developments, we conducted a literature search on moose in the northeastern United States and distributed a questionnaire and conducted phone interviews with biologists responsible for moose management across the region to determine the status and management of moose in New England and New York. Furthermore, in 2006 we initiated a study on the home ranges, movements, and habitat use of moose in Massachusetts. We captured and collared moose with Global Positioning System (GPS) collars to track their movements in the Commonwealth. The surveys and interviews with the state biologists revealed that moose populations appeared to be stabilizing in southern New England. However, the moose population continued to grow in northern New York. Moose populations in northern New England were managed with an annual fall harvest, but moose hunting was not allowed in southern New England or New York. Throughout the region moose vehicle collisions were a major concern (>1,000 occur each year) including several that resulted in human fatalities. The collaring study has revealed the importance of maintaining a variety of forest cover types, age classes, and wetland habitats to meet the seasonal needs of moose, including early successional habitats created by logging that appear to be important for moose. Mean home range sizes were 64.9 km2 (SE = 12.9) and 73.3 km2 (SE = 9.4), respectively, for females and males in central Massachusetts, and 164.5 km2 (SE = 62.6) for males in western Massachusetts. Moose often interacted with roads and human development on the uplands, but used less developed areas of their home ranges. This demonstrates the importance of preserving the integrity and connectivity of the forested landscape of Massachusetts.

Improperly designed road-stream crossings can fragment stream networks by restricting or preventing aquatic organism passage. These crossings may also be more vulnerable to high flow events, putting critical human infrastructure at risk. Climate change, which will require access to suitable habitat for species persistence, and is also predicted to increase the frequency and magnitude of extreme floods, underscores the importance of maintaining stream connectivity and resilient infrastructure. Given the large number of road-stream crossings and the expense of replacement, it is increasingly important to prioritize removals and account for the multiple benefits of these management actions. I developed an aquatic barrier prioritization scheme that combines potential habitat gain, stream thermal resilience, aquatic organism passage, and culvert risk of failure. To assess relative thermal resilience, I deployed paired air-water thermographs in several New England watersheds and analyzed relative thermal sensitivity (relationship of water to air temperature) and exposure (duration, frequency, and magnitude of warm stream temperature episodes) among streams. These were combined into a single metric of thermal resilience corresponding with the distance of that stream’s sensitivity and exposure from the watershed median. To test the relationship between risk of failure, culvert dimensions, and stream connectivity, I developed a logistic regression to predict risk of failure using data from two watersheds that experienced extreme flooding from Hurricane Irene (2011). Finally, I applied the resultant prioritization scheme to 66 road-stream crossings in the Westfield River watershed (MA). Thermal habitat quality varied considerably within and among watersheds. Stream sensitivity was generally lower than the widely accepted 0.8 ̊C increase in stream temperature for every 1 ̊C increase in air temperature (Westfield median sensitivity = 0.44), with substantial differences among streams. Exposure also varied widely among streams, indicating that some headwater streams in New England are more thermally resilient than previously thought. Risk of infrastructure failure was predicted with a logistic regression using culvert constriction ratio and predicted aquatic organism passage as predictors (Likelihood ratio test, X2=59.1, df=3, p- value=9.2e-13), indicating that underdesigned culverts were more likely to be barriers to passage and more likely to fail in extreme flow events. To prioritize culverts, this study ultimately used a piecewise approach that identified culverts opening the longest reaches of thermally resilient habitat, and then ranked those culverts by infrastructure replacement need. In the Westfield River, the prioritization clearly identified crossing replacements most likely to yield multiple benefits. The scheme I developed can accommodate changes in the relative weights of the different criteria, which will reflect differences in management and conservation concerns in the confidence of inputs. In conclusion, increasing connectivity by removing barriers may be one of the most effective ways to mitigate the effects of climate change on aquatic systems, but it is important to remove the right barriers.

Mars was assumed to be very similar to Earth in terms of topography, water, magnetic field, and even the existence of life. However, exploration of the planet in the 1960s by the Mariner missions showed us a very different planet, one very unlike our own. The later discovery by the Mars Global Surveyor (MGS) of the lack of a globally generated magnetic field proved just how different Mars is from Earth. The discovery of strong magnetic remanence (on the order of 20 – 30 A/m) on Mars implies that at some point in Mars’ history there was a magnetic field, and therefore a dynamo. Since a globally active magnetic field is not present, it can also be assumed that the dynamo ceased generation. Basaltic rocks on Earth typically have magnetic remanences between 1 to 4 A/m and do not usually hold on to those remanences for billions of years. In this study, I utilized the information available on the geochemistry, age, and magnetics of Martian rocks in an attempt to find appropriate terrestrial analogs. Seven Earth locations of basaltic rocks (Mauna Loa, Hawaii; Eldgja and Laki eruptions, Iceland; Springerville volcanic complex, Arizona; Taos Plateau volcanic complex, New Mexico; Lascar Volcano, Chile; Tatara-San Pedro volcanic complex, Chile; Patagonia slab window, Argentina) were selected with different tectonic environments, ages, and geochemistries and their rock magnetic properties including natural remanent magnetization (NRM), susceptibility, and hysteresis properties including coercivity were analyzed. Geochemical values were plotted as averages on a silica vs. alkali graph. There was some variation in NRM and susceptibility values for each of the terrestrial locations (such as Taos Plateau), but overall the averages are a good representation of average NRM and susceptibility. None of the samples studied displayed high remanence, high susceptibility, and high coercivity that would indicate stable single-domain magnetite. Although vastly different basalt origins were studied, an analog to the highly magnetized Martian crust was not found. There are three possibilities for this. 1) A basaltic terrestrial analog does exist, yet it was not included in this study. This is a very viable possibility since there are basalts all over the Earth each with a unique origin. 2) A basaltic terrestrial analog does not exist because although the rocks on Mars are basaltic, the global magnetic field that existed billions of years ago on Mars was unlike that of Earth. Recent work (Stanley et al, 2008) has shown that the Martian magnetic field might be completely different from Earth’s, and therefore a terrestrial analog would be impossible to find. 3) A basaltic terrestrial analog does not exist, but a terrestrial analog of a different rock type does exist. The assumption that the surface rocks on Mars – which are known to be mostly basaltic – are the carrier of the high magnetism. There is the possibility that the surface may be the origin of the magnetism, and in the areas of extremely high magnetism the rocks might locally be different. Also, it may not be the surface rocks that are exhibiting the magnetism. It may be buried highly magnetic rocks under a basalt lava flows. In addition to seeking out other basalts as terrestrial analogs for to the highly magnetized Martian rocks, it would also be worthwhile to investigate the possibility of a different magnetic field for Mars and what other terrestrial rocks could display such high magnetism billions of years after the termination of the Martian magnetic field.

ABSTRACT SALT DRIVE IN THE BEAVER (Castor canadensis): AN EXPERIMENTAL ASSESSMENT WITH FIELD FEEDING TRIALS SEPTEMBER 2012 JENNIFER E. STRULES, B.M. BERKLEE COLLEGE OF MUSIC M.S., UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Stephen DeStefano Salt drive is a seasonal phenomenon common to several classes of wild herbivores. Coincident with shifts of nutrient quality when plants resume growth in the spring, sodium is secondarily lost as surplus potassium is excreted. The beaver (Castor canadensis) is an herbivore whose dietary niche closely follows that of other herbivores that are subject to salt drive, but no published studies to date have assessed the likelihood of its occurrence. To quantify if beavers experience seasonal salt drive, we designed a field experiment to measure the foraging responses of beavers to sodium-enhanced foods. We used sodium-treated (salted) and control food items (aspen [Populus tremuloides] and pine [Pinus spp.] sticks) during monthly feeding trials at beaver-occupied wetlands where water lily (Nymphaea spp. and Nuphar spp.) was present and where water lily was absent. If conventional ontogeny of salt drive was operant, we expected to observe greater utility of sodium-treated food items by beavers in May and June. Further, if water lilies supplied beavers with sodium to meet dietary requirements as is widely speculated, we expected foraging responses to sodium-treated food items at wetlands where water lilies were absent to be greater than at wetlands where water lily was present. Aspen was selected by beavers in significantly greater amounts than pine. There was no difference between the mean percent consumed of salted and control aspen sticks by beavers at lily and non-lily wetlands, and no differences in temporal consumption associated with salted or control pine sticks at either wetland type. Salted pine was consumed in greater amounts than unsalted pine. We propose that the gastrointestinal or renal physiology of beavers may predispose them to low solute loss, thereby preventing salt drive.

An investigation into the spatial ecology and effects of catch-and-release angling on the physiology and behavior of striped bass was conducted. Fine-scale behavior was assessed by tagging fish with acoustic transmitters equipped with pressure and tri-axial accelerometer sensors and tracking them within a fixed array (n=34 receivers) in a Massachusetts estuary. Activity space changed significantly over the course of the season and increased with water temperature. Striped bass most frequently exhibited low levels of locomotory activity representing 67% of total activity measurements, with occasional high activity and burst swimming, often within the upper 3 m of the water column. Depth distribution of striped bass remained shallower when temperatures peaked at over 21 oC. Diel vertical migration was present with shallowest depths observed during the day and greatest depths during high tide. To investigate catch-and-release consequences, 102 striped bass were angled and blood sampled between July and November 2011. A subsample of 35 striped bass (July n=11, August n=11, September n=13) were implanted with tri-axial acoustic accelerometers to assess relative behavior and survival post-release. Results from principle component analyses produced five factors describing 72.7% of the variance for blood physiology parameters, total length, and water temperature. Subsequently, only eigenvalues from PC1, with high loading for blood lactate, plasma sodium and chloride, and total length, were significantly correlated with fight time. Eight individual fish were detected within 12 hours of release and exhibited their greatest mean daily activity space estimate within that time (1.5 km2 ± 0.6, 50%; 5.6 km2 ± 2.2, 95%). Depth ranged from 0-6.15 m (1.89±1.3 m) and acceleration ranged from 0.095-3.51 ms-2 (0.95±0.33). In summary, no observed mortality suggests that fish were able to recover from the physical and physiological impacts of angling. This thesis has increased the understanding of striped bass ecology and will help promote future conservation and management initiatives for striped bass and facilitate additional research.

Populations of anadromous brook trout can be found from northern Canada into New England. It is believed that the extent of anadromy exhibited by coastal brook trout populations decreases with latitude, but the ecology and movements of the more southern populations are less studied. A 33-month acoustic telemetry study of anadromous brook trout (Salvelinus fontinalis) was conducted in a restored coastal stream and adjacent marine system in southeastern Massachusetts. Movement and migration patterns of 54 brook trout were investigated for individual differences and common features. Individuals exhibited a range of movement patterns. Some were more resident and only moved short distances, while others moved great distances covering the entire stretch of the stream (7.25 km) and moving into the marine environment. General Additive Mixed Models revealed that date was the major influence on brook trout movement between habitats and predicted peaks in movement in the spring and fall. Downstream movement peaked in the spring and in the fall, suggesting post-spawning feeding migration. Fish transitioned between habitats more often at new and full moons and when stream temperature was between 8 and 12 °C. Upstream transitions peaked as temperatures declined in winter 2011. Fifty percent of tagged brook trout were detected in the estuary during the study, suggesting that it is an important habitat for the population. In summer 2012, 14 tagged brook trout (20% of active tags) resided near one receiver at the head of the tide, which contained a thermal refugium in the form of a cold-water spring seep. Of the 84 tagged brook trout, 9.5% moved to the marine environment. Warm temperatures in saline Buttermilk Bay in the summer and cold temperatures in winter probably discourage some individuals from entering the marine environment. Compared to more northern coastal populations of brook trout, the Red Brook population appears to be less anadromous.

Recent years have seen an explosion of interest in the use of freely available DNA present in aquatic systems, otherwise known as environmental DNA (eDNA), as a tool for monitoring aquatic organisms. However, much remains unknown about the behavior of eDNA over a range of environmental conditions. This is particularly true in high gradient headwater streams, which have received less attention than other types of water bodies. In the summer of 2011, a headwater stream system with well established species distributions was sampled using eDNA techniques. Though species were detected where known to be present, detections also occurred where traditional techniques failed to detect species. This suggests that a cautious approach to positive eDNA detections is advisable. In 2012 a second study was conducted to better understand the dynamics of eDNA concentration in lotic systems. Caged brook trout (Salvelinus fontinalis) were introduced into two otherwise fishless headwater streams, and eDNA samples were collected at evenly spaced intervals downstream of the cage. This was repeated 19 times from mid-summer through autumn, over flows ranging from approximately 1 to 96 l/sec. Quantitative PCR was used to relate DNA copy number to distance from source for each of these 19 sampling events. In all cases, DNA was detectable at 239.5 m from the cage. Increasing flows generally decreased eDNA copy number near the cage but had relatively little effect at downstream sites. Additionally, the presence of leaf biomass during the fall period had the potential to completely erase otherwise high DNA levels.

Human disturbance is becoming an ever-bigger threat to biodiversity across the globe and should continue to be a field of conservation priority. Urbanisation, research and tourism put unavoidable pressure on the surrounding flora and fauna, therefore we need to gain knowledge on how to reduce future harm. Here we investigated the effects of human presence on medium-large terrestrial mammals in the south-eastern Peruvian Amazon, using camera traps to measure the number of human and mammal observations at varying distances from our research centre and the hiking trails. Species richness and the Shannon and Inverse Simpson diversity indices were also calculated during the four-month study period. Nineteen species were detected across fourteen camera sites. Distance from camp was positively correlated with species richness and the diversity indices, but showed no correlation with total mammal observations. Distance from nearest trail was negatively correlated with species richness, total mammal observations and the diversity indices. Total human observations was negatively correlated with species richness and the diversity indices, but had no impact on total mammal observations. Nevertheless, these results often had high p-values and low sample size and therefore should be interpreted with caution. Omnivores were the most sensitive trophic guild, showing a statistically significant negative correlation with total human observations, and a statistically significant positive correlation with distance from nearest trail. It is important then to assess these responses to human disturbance at the community and species level, as to truly understand the impact we are having.

Spotted Salamanders, Ambystoma maculatum, are a widely distributed pond-breeding amphibian that spends an estimated 95% of its life in woodlands surrounding breeding ponds. Their terrestrial ecology remains poorly understood. Few studies have tracked the movement patterns of Spotted Salamanders, and they have given limited information on fine scale patterns. Studies of distribution around vernal pool environments have brought increased attention to their terrestrial ecology. To this end I tracked a sample of Passive Integrated Transponder (PIT) tagged animals with a Radio Frequency Identification Device (RFID). Quadrat-variance methods and a Poisson distribution were used to analyze spatial distribution patterns over 2 years. The home range size of 10 Spotted Salamanders was calculated using the revised minimum area method. A clumped distribution was found at larger spatial scales, except in the first year of the study. Home range size was shown to be limited and highly variable among 10 individuals (Mean=4.29m2, Standard Deviation=6.25).

The Hermit Thrush is a new breeding bird in the Southern Appalachian high-elevation mountains, having expanded its range southward over the last few decades. Here it is sympatric with the Veery, a congeneric breeding resident. In order to more fully understand why the range expansion took place and to understand more about the local ecology of the newly arrived bird, I measured several habitat variables in 30 Hermit Thrush and 24 Veery territories. Principal Components Analysis and Cluster Analysis brought to light several patterns of habitat preferences for these 2 species. Hermit Thrushes prefer territories with more leaf litter on the ground and less shrub density than Veery territories. Competition between these species should remain low, as their niche differences brought to light in this study should enable them to breed in close proximity to each other in these high-elevation mountains.