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Allegheny College Allegheny College DSpace Repository http://dspace.allegheny.edu Projects by Department or Interdivisional Program Academic Year 2016-2017 2017-05-02 Determining How Varying Severity of Forest Fragmentation Effect Red-backed Salamander Movement Patterns Sadler, Abrianna http://hdl.handle.net/10456/42792 All materials in the Allegheny College DSpace Repository are subject to college policies and Title 17 of the U.S. Code. Determining How Varying Severity of Forest Fragmentation Effect Red-backed Salamander Movement Patterns By Abrianna Sadler Department of Environmental Science Allegheny College Meadville, Pennsylvania April, 2017 Determining How Varying Severity of Forest Fragmentation Effect Red-backed Salamander Movement Patterns i Table of Contents Abstract ……………………………….…………… iii Introduction.………………………………………. 1 Habitat Loss…………………….………… 1 Protected Areas…...…………….………… 2 Vulnerability of Plethodontid Salamanders to Habitat Loss…………………….……... 2 Ecological Importance of Plethodontid Salamanders…………………….……........ 3 Red-Backed Salamanders……….………. 4 Forest Fragmentation Impact on RedBacked Salamanders…………….....…….. 4 Fragmentation within Pennsylvania Protected Areas…………………….…….. 6 Research Objective……………………......………… 6 Methods ……………………………………………. 7 Study Site Selection ………………..…...... 7 Quantifying Movement Data …….……… 8 Procedure …………………………..…...... 8 Statistical Analysis ………………….……. 10 Results ...…………………………………………… 10 Discussion …………………………………………. 14 Conclusion ………………………………. 17 Works Cited ...……………………………………… 20 ii Name: Abrianna Sadler Major: Environmental Science Thesis Committee: Dr. Casey Bradshaw-Wilson, Dr. Matt Venesky Date: Spring, 2017 Title: Determining How Varying Severity of Forest Fragmentation Effect Red-backed Salamander Movement Patterns Abstract Terrestrial salamanders occupy a wide range of habitats globally. Within the United States, including Northeastern forests, there is an extremely high diversity and abundance of these organisms. Typically, the most abundant species of terrestrial salamander within eastern United States forests are Red-backed salamanders (Plethodon cinereus). These salamanders are important to forest ecosystems because they play a key role in nutrient cycling and are indicators of ecosystem health. One of the most devastating threats to terrestrial salamanders is habitat loss and fragmentation due to human activity. This creates edge effects which alter and degrade terrestrial salamander habitat. Habitat fragmentation is happening globally, even in protected areas such as Woodcock Creek Lake Park in Crawford County, PA where Red-backed salamanders are abundant. This study examined the impact that fragmented forests within this protected area have on Red-backed salamander movement patterns focusing on directionality, total distance traveled, net distance, and linearity in response to three degrees of fragmentation: paved roads, hiking trails, and no fragmentation. Total distance moved was found to be greater in core sites versus trail and road sites (p < 0.05) while net distance was the same for core and trail sites but decreased for road sites (p < 0.05). No abiotic factors documented correlated with any of the three movement patterns and only soil temperature was found to differ between the three fragmentation treatments, with temperatures being lowest in core sites (p < 0.05). Individuals showed no directional avoidance of either forest fragmentation although no Red-backed salamanders attempted to cross the road or the hiking trial. Prioritizing the conservation of nonfragmented forest habitat, especially in protected areas, is essential to preserving terrestrial salamander diversity and population and intern maintaining healthy forest ecosystems. iii Introduction Habitat Loss One of the largest threats to biological diversity and wildlife populations is habitat loss, destruction, and fragmentation (Meffe et al. 1997). As human development exponentially increases, ecosystems are being severely altered. These altered habitats are unable to sufficiently provide crucial resources such as food, water, or protection and may lose the ability to harbor organisms. Habitat loss or destruction is characterized by degradation and fragmentation (Meffe et al. 1997). Fragmentation is the process by which a large continuous area of habitat is both reduced in area and divided into two or more smaller segments. These remaining segments are often isolated by highly modified or degraded landscapes. They are different from the original ecosystem in that they have a greater amount of edge per area of habitat, the center of each habitat fragment is closer to the edge, and large populations are divided into smaller ones (Primack, 2010). The edges of fragmented landscapes experience altered ecological properties coined ‘edge effects’ (Saunders, 1991). Within anthropogenically segmented forests, sites are typically divided and surrounded by habitats with low biomass and low structural complexity such as roads, fields, towns, or other types of human development exacerbating these edge effects. The altered set of conditions act as a gradient; as the distance from the fragment into core forest increases the environment becomes more suitable and stable for wildlife (Murcia, 1995). There are three types of edge effects produced on the fragment; abiotic effects, direct biological effects, and indirect biological effects. Abiotic effects are changes in a habitat that result from being close to a structurally different environment. They can also come about from the inflow of chemicals across the edge that change environmental conditions (Murcia, 1995). When a forest is cleared, the ground becomes hotter based on its exposure to direct sunlight. Reduced canopy cover leads to increased soil temperature during the day, decreased temperatures at night and increased wind exposure which dries out soil and vegetation. The lack of canopy cover also decreases leaf litter depth and downed woody debris (Murcia, 1995). Direct biotic effects involve changes in abundance of species due to the physical conditions near the edge. Forest edges may be occupied by species of plants and animals different from those found in the forest interior. Indirect biotic effects are changes in species behavior and interaction such as competition or predation (Murcia, 1995; Gehlhausen et al., 2000). The reach of these edge effects due to 1 fragmentation vary, ranging from 20 to 80 meters from the edge (Marsh & Beckman, 2004; DeMaynadier and Hunter, 2000; Murcia, 1995). Fragmentation within Pennsylvania Protected Areas Protected areas are the most widespread and effective means of conservation to combat habitat loss (Jenkins et al., 2015). They can take on many different forms such as national parks, wilderness areas, nature reserves, and community conserved areas. Within Pennsylvania 17% of the total land area is dedicated to terrestrial protected areas (National Gap Analysis Program, 2016). The governmental implementation of protected areas started in the early 19 century with an initial goal to preserve large wild areas for wildlife protection and human recreation (Eagles et al., 2002). Today protected areas have grown to occupy about 14% of the United States total land area (National Gap Analysis Program, 2016). The purpose of these areas have also grown. They strive to achieve the long term conservation of nature, its ecosystem services, and its associated cultural values in addition to the original landscape preservation (IUCN, 2007). Terrestrial protected areas help maintain ecosystem integrity, conserve biodiversity, and prevent habitat fragmentation through the restriction of land use, extraction, and human actives (Kroner et al., 2016; Angermeier, 2000; Ridder, 2007). Although, it has recently been suggested that protected public lands within the United States may be too small and fragmented for sufficient preservation of biodiversity (Haddad et al., 2015). Protected areas contain roads and trails that are fundamental in providing access to forested ecosystems for recreation use. They allow people to experience and study nature but they also fragment the landscape (USDA, 2001). A study by Heilman et al. (2002) found that protected areas do indeed contain less fragmentation than unprotected areas. Understanding the effects roads and trails have on the forest habitat, and high importance conservation species can help make crucial decisions on whether or not to continue protecting already protected areas, a topic that has recently become a political controversy (Marsh & Beckman, 2004). Woodcock Creek Lake Park is a recreational protected area located in Crawford County, Pennsylvania with maintained trails and roads that wind throughout the park. It is the largest recreation facility managed by the county and attracts well over 13,000 visitors during peak season (i.e. Memorial to Labor day) (Recreational Areas, n.d.; Woodcock Creek Lake Park, PA, n.d.). 2 Vulnerability of Plethodontid Salamanders to Habitat Loss Plethodontid salamanders, one of the most species rich and abundant families of salamanders within the United States, are particularly vulnerable to habitat loss and alteration due to their environmental sensitivity. (Scheffers & Paszkowski, 2012; Burton and Likens, 1975). These lungless amphibians breathe via subcutaneous respiration; their skin must be kept moist to permit efficient gas exchange. The high permeability of their skin, however, leaves them susceptible to desiccation which limits their home range to moist, cool environments (Feder, 1983). It also restricts activity to times when soil moisture is high. During dry periods they are forced to remain in saturated areas beneath woody debris, under rocks or in holes for extended periods of time (Spotila, 1972; Spotila and Berman, 1976; Feder, 1983). Even when ecological conditions are suitable, terrestrial salamanders risk desiccation during movement (Feder, 1983). These specific habitat requirements in addition to their low mobility and small size make terrestrial salamanders sensitive to disturbances such as habitat alterations (DeMaynadier & Hunter, 1995; Semlitsch et al., 2007; Welsh & Droege, 2001). Ecological Importance of Plethodontid Salamanders Plethodontidae salamanders (Order: Caudata) are a vertebrate taxa that play important ecological roles in a multitude of forest ecosystems. This is because they are diverse and often abundant, occupying a widespread range of habitat types. Of the 400 species of salamanders globally, which account for 8.5% of all known living amphibian species, 127 are found within the United States (citation). Northeastern forests hold an extremely high diversity of salamanders, with the Appalachian Mountains having more than anywhere else in the world (Mathewson, 2006). Salamanders are an integral element of forest ecosystems; they occupy a vital mid trophic level position and serve as indicator species of variables related to environmental stress (Welsh and Droege, 2001; Whiles et al., 2006; DeMaynadier & Hunter, 1995; Semlitsch et al., 2007). The population density and wide distribution of terrestrial salamanders, in addition to their small size (ranging from 5 to 13cm), make them top predators in the forest floor foodweb (citation). They regulate the population of invertebrates and soil micro fauna, which are too small for birds and mammals to eat, maintaining a diverse prey population (Frasier, 1976; Jaeger, 1972). They are highly efficient at converting food into energy and are crucial in controlling leaf 3 litter breakdown and nutrient cycling on the forest floor. Sixty percent of their total consumption is converted into biomass, increasing protein, making them a high quality prey item for snakes, birds and small mammals (Burton & Likens, 1975; Wyman, 1998, Rooney et al.,2000, Walton et al.,2006, Walton, 2013; Best & Welsh, 2014). Red-backed Salamanders The most abundant Plethodontid salamander within eastern United States forest are Redbacked salamanders (Plethodon cinereus) (Marsh et al., 2005). This generalist species is a fully terrestrial salamander that can be found in high densities of 0.2–8.2 m−2 throughout its range (Noel et al., 2007; Bailey, Simons, & Pollock, 2004). They breed and nest terrestrially under rocks, woody debris, and within the soil (Lynn & Dent, 1941; Ng and Wilbur, 1995). Their home ranges are near 13m2 for males and juveniles and 24m2 for females (Kleeberger & Werner, 1982). During wet periods, Red-backed salamanders avoid over saturated soils by escaping to the forest floor. Characteristics that allow them to display such a wide habitat range include their ability to survive in dry areas for a longer length of time than other salamander species and their typically solitary and nocturnal nature, although they will forage during the day in in the leaf litter and under cover objects staying in cool and sheltered environments (Burton, 1976; Burger, 1935). Worldwide, Red-backed salamanders have been known to climb vegetation and trees, burrow into soil, and move horizontally throughout forest habitat (Roberts & Liebgold, 2008). This species is extremely territorial of the cover objects they occupy and have been known to ram the canthus rostralis of other salamanders (Gergits, 1982). In Pennsylvania, fully terrestrial juveniles become active by the end of September, after hatching in late august (Sayler, 1966). Overall, Red-backed are a relatively immobile species, as are most within the Plethodontidae family. Forest Fragmentation Impact on Red-backed Salamanders Studies support forest fragmentations impact on Red-backed salamanders’ abundance, genetic diversity, and potentially, movement. Consistently, a greater abundance of terrestrial salamanders is linked to a wealth of leaf litter coverage and depth, high soil moisture, high percentage of canopy cover, and moderate soil temperatures all of which decline within fragmented habitat (Faccio, 2003; Regosin et al., 2005; Rittenhouse and Semlitsch, 2006). 4 Specific characteristics make them hypersensitive to direct effects produced by forest fragmentation including their permeable skin, low dispersal ability, and constant contact with the forest floor (Feder, 1983; Stebbins & Cohen, 1995; DeMaynadier & Hunter, 1998). There have also been genetic implications from forest fragmentation identified in Redbacked salamanders. Following a sharp reduction in population size and inter-population connectivity due to human activity, such as fragmentation, populations may experience loss of rare alleles and diminished heterozygosity through genetic drift. Inbreeding can also occur, increasing the chance offspring will be affected by recessive or damaging traits (Noel et al., 2007). Genetic drift and inbreeding cause loss of genetic diversity and can lead to lowered fitness and an increased risk of extinction (Reed & Frankham, 2003). One study found that populations of Red-backed salamanders in fragmented habitats are genetically differentiated from those living in core areas and have lowered genetic diversity (Noel et al., 2007). Since genetic diversity leads to greater fitness and increased ability to adapt to changing environments, survival of Redbacked salamanders may be at risk (Young et al., 1996; Reed & Frankham, 2003). Research has indicated that there are direct impacts from forest fragmentation on terrestrial salamanders as well. When crossing over open habitat caused by fragmentation there are increased risks of desiccation, predation, and mortality from road vehicle collisions (Carr & Fahrig 2001; Murcia, 1995). Species with high vagility are strongly affected by these factors because they cross open habitats more frequently (Carr & Fahrig, 2001). The intensity of edge effects on terrestrial salamanders along different severities of fragmentation has produced conflicting results. In a study by Marsh (2007) examining the effect of wide ungated and narrow gated roads on salamander abundance, researchers found consistent edge effects on ungated roads that were not detectable along gated roads (Marsh 2007). Contrarily, other studies have found that forest roads have degraded habitat characteristics independent of traffic intensity or public access (Marsh & Beckman, 2004; Semlitsch et al., 2007). While Marsh et al. (2005) found evidence that gravel recreational roads and small paved roads are minor barriers to salamander movement, showing that the smallest amount of fragmentation may change behavior contradictory to his later findings that narrow roads create no significant biotic changes. Many studies examine how edge effect impacts terrestrial salamander abundance, but not how it directly impacts their behavior (Gibbs, 1998; Marsh & Beckman, 2004; Semlitsch et al., 5 2007; Test and Bingham, 1948; Jaeger, 1980; Taub, 1961). Few discuss movement in response to fragmentation while most that do use abundance or displacement experiments to infer movement. A small number of studies observe direct behavioral impacts of fragmented areas. When Red-backed salamanders were displaced, roads significantly reduced return rates by an average of 51% and the type of road substrate did not seem to impact movement. Return rates were the same for open fields and forest habitat (Marsh et al., 2005). Terrestrial salamanders within previously clear-cut habitat were found to have smaller home ranges and spent more time under cover objects and burrowed in the soil. Studies tended to examine biological factors such as snout vent length, body mass, and sex rather than abiotic factors (Marsh et al., 2005; Marsh & Beckman, 2004; Cosentino & Droney, 2016). Research Objective The objective of this study was to determine the impact forest fragmentation within Woodcock Creek Lake Park, a protected area in Crawford County, PA with an abundance of Red-backed salamanders, has on Red-backed salamander movement patterns. Movements were recorded in two categories total distance moved and net distance moved. Three fragmentation types found throughout Woodcock Creek Lake Park were examined, hiking trails, paved roads, and non-fragmented areas. It was hypothesized that the highest degree of fragmentation (i.e., paved roads) would have the most severe edge effects and a negative impact on salamander movement. Decreased canopy cover and increased soil temp along roads would force Redbacked salamanders to take refugee within cooler soils. They would also show an avoidance of net movement towards fragmentation. The hiking trail would still impede movement but to a lesser degree. Non-fragmented areas would have unrestricted movement, and salamanders would have the ability to remain above ground for longer distances due to habitat suitability increasing total movement. They would have ideal habitat characteristics so net displacement would be greatest in these areas allowing for a larger range. Methods Study Site Selection Research was conducted at Woodcock Creek Lake Park and State Game Lands #435 in Crawford County, PA (Figure 1). Three types of forest fragmentation were examined; paved 6 road fragmentation, gravel hiking trail fragmentation, and no fragmentation. This was assessed at seven sites; two gravel hiking trails, two paved roads and three core sites. Previous studies have shown edge effects do not reach past 80 m from the forest edge for Red-backed salamanders; therefore, sites were established based on an 85 m distance between each site and any outside type of fragmentation (Marsh & Beckman 2004; DeMaynadier and Hunter 1998). Potential site locations were initially chosen using google maps to estimate the distance between fragmented habitat before physically visiting Woodcock Creek Lake Park and State Game Lands #435 (Google Search, 2015). The sites were ground-truthed by manually walking to the predetermined spots, in no particular order, and measuring distance between potential research locations and the nearest outside type of fragmentation. Once one of the final seven sites was chosen, abiotic factors were measured at five geographical points within the surrounding continuous forest, to confirm that sites were ecologically similar between one another. This was done only one time during the study and included leaf litter depth (cm), percent canopy cover, soil temperature (C), and average number of cover objects taken within a 2-meter square at each point. Canopy cover was measured by placing a 5 by 5 square grid on the forest floor and counting the number of squares shaded by vegetation (PA DEP 2010). This was multiplied by four to get a canopy cover percentage. Leaf litter depth was measured from the bare soil to the top of the uncompressed leaf litter using a ruler. Soil temperature was determined using a soil thermometer that was inserted into the ground at a standardized depth. This data was collected from each of the seven sites within a 12 hour period. Hiking trails were located off Half Rite Trail (HS1 and HS2) and road trails were off Boat Launch Road (RS1 and RS2). Two core transects were located within Woodcock Creek Lake Park and one in State Game Lands #435. Figure 1: Satellite map identifying sites surveyed in Woodcock Lake Park, Crawford County PA for Plethodon Cinereus movement where CS (core site) represents no fragmentation, RS (road site) represents most severe fragments, and HS (hiking trail site) represents less fragmentation (Google Search 2015) 7 Quantifying Movement Data ZQ Pigment powder (DayGlo Co. Columbus, OH) was used, which is a noninvasive method used to track movements of small organisms in this case to mark and follow salamander trails (Miloski, 2010). It has been determined that the powder is harmless to small mammals and amphibians and can be repeatedly applied without negative side effects (Lemen and Freeman, 1985; Orlofske et al., 2009). This technique provides information similar to radio tracking, but with better spatial accuracy (Eggert, 2002). Additionally, it highlights the paths traveled both horizontally and vertically, which may be an important component of certain salamander species’ movements including Red-backed. The use of different colored pigment powder on multiple individuals in the same site enabled trails to be distinguishable from one another (Eggert, 2002). This allowed for the collection of data from every individual found within a transect in a single day. The pigment powder tracking method is inexpensive, easy to use, applicable to all salamander sizes, and provides an exact record of movement when there is minimal rain. Procedure Data collection spanned from October 8, 2016 until November 22, 2016. Percent canopy cover, leaf litter depth, and soil temperature were taken at one point from each the left, center, and right regions of the transect to compute average abiotic factors of that transect every time a site was visited. These variables were recorded the same way as previously outlined. Air temperature, obtained from AccuWeather, and hours since last rainfall were also documented. At each site, all cover objects within the 50 by 5 meter transect were turned to search for salamanders. The total number and the type of cover object (i.e. log or rock) were recorded. 8 Figure 2: Diagram illustrating how transects were constructed at all the sites. Each transect was 5m by 50m and at least 85m from any other form of forest fragmentation. When a Red-backed was found, its head direction was recorded using a compass. They were placed in a Tupperware container for pigmentation. This was done outside of the transect to prevent contamination. A paint brush was dipped into either the Aurora Pink or Horizon Blue pigment powder and dusted onto the front and back of each salamander. Pigmentation was most effective when powder was on the base of Tupperware before the salamanders were placed inside. This allowed for coating of the underneath, sides, and top of the body as recommended by Fellers and Drost (1989). The pigmented Red-backed was returned to the exact location of collection and placed in the same head direction to prevent influence on direction of movement. The cover object was placed back on top and the site was marked with a numbered flag to allow for identification and following. Latex gloves were worn and disposed of in between each salamander to prevent transfer of any potential pathogens. Leaf litter depth, soil temperature, and time of pigment were also recorded at each point where a salamander was found (Miloski, 2010). After twenty-four hours, to allow enough time for salamander movement, transects were revisited and distance moved by each salamander was recorded (Graeter et al,. 2007; Miloski, 2010). As each Red- backed moved, the applied powder brushed off onto the soil, leaf litter, trees, and cover objects leaving a trail. This trail was followed using an ultraviolet flashlight until the path went into a burrow hole or disappeared, or when the salamander was found. Each turning point was marked with a flag and then the path was traced using string. The trails each 9 individual left were mapped on graph paper using a tape measure and compass (Roe and Grayson, 2008). Total distance traveled was determined by summing the distances individuals moved after each change in direction. Net distance was determined by measuring from the start to end point of each path. Linearity was computed by dividing net displacement by total path length. From this information, how edge effect influenced salamander movement could be qualified by comparing total distance, net distance, and path linearity of species found along the edge versus species found within a core area (Cline & Hunter 2016). Statistical Analysis F-test was used to determine variance and then two sample T-test was used to test between the three movement variables (total distance, net distances, and linearity), and the three fragmentation treatments (road, hiking trial, and non-fragmented sites), as well as the three movement variables and the abiotic factors of each transect (leaf litter, soil temperature, and canopy cover). These were the average measurements found for an entire transect on a single day. Regression plots with trendlines were produced to note any correlation among the recorded abioitic factors and the total distance traveled, the net distance traveled, and the tortuousity of each individual followed. Results One hundred and forty-one Red-backed salamanders were found within transects and pigmented. Of the 141 salamanders, 17 pigmented trails were lost due to excessive rainfall or wet ground cover, while 5 of the trails were successfully followed back to the initially pigmented salamander. The remaining 120 movement trails (53 at core sites, 42 at trail sites, and 25 at road sites) ended with individual salamanders retreating into the ground. When light rain persisted in the 24 hour period between pigmentation and tracking, trails were still able to be successfully followed to either the pigmented individual or into the ground. Only when heavy rain occurred did trails become washed out and unable to follow. The total movement of Red-backed salamanders was significantly different when comparing the three fragmentation treatments (Figure 3A and 3B). Individual salamanders moved a greater distance in the core sites as opposed to trail sites (p = 0.016). They also moved more in core sites in comparison to road sites (p = 0.001). Although total distance traveled at trail 10 sites was greater than road sites, no significant difference was found between the two fragmentation types (p = 0.10). A 120 A 100 1 Core 6 Trail 11 16 21 26 31 36 41 46 51 Total Distance Moved (cm) Total Distance Moved (cm) B 500 450 400 350 300 250 200 150 100 50 0 80 B B 60 40 20 Salamander Number Road 0 Core Trail Road Figure 3: Total distance moved between the core, trail, and road fragmentation treatment. A: Number of salamanders followed into burrows categorized by site type. Shows total distance moved for each individual. B: Differences in average total movement between each fragmentation treatment. A and B labels show significance between the Core, Trail, and Road in respect to total distance moved. When examining net movement (Figure 4A and 4B), road sites showed decreased distances when compared to both core sites (p < 0.001) and trail sites (p < 0.008). Core sites did not have a significantly greater average net movement than trail sites (p = 0.16). A A 50 A 200 150 100 50 0 1 Core 6 Trail 11 Road 16 21 26 31 36 41 46 51 Net Distance Moved (cm) Net Distance Moved (cm) B 250 40 B 30 20 10 Salamander Number 0 Core Trail Road Figure 4: Net distance moved between the core, trail, and road fragmentation types. A: Number of salamanders followed into the ground categorized by site type. Shows net distance moved for each individual. B: Differences in average net movement between each site type. A and B labels show significance between the Core, Trail, and Road in respect to net distance moved. Among the three sites, no differences were found in linearity. Percent canopy cover and number of cover objects flipped illustrated no significant distinctions between any of the three fragmentation types (p > 0.05). There were more overall cover objects flipped in core transects versus trail transects and more in trail transects versus road transects. When comparing soil temperatures (Figure 5A) and leaf litter depths (Figure 5B) of each individual Red-backed 11 followed among treatments, soil temperature was least at core sites when compared to road sites (p < 0.001) and trail sites (p < 0.001). Trail sites had warmer soils on average, but not to a notable degree. Leaf litter depth showed no significant difference regardless of fragmentation type, however, when examining core and road habitats, leaf litter depth was notably less along the road (p = 0.072). 9.4 4 B Soil Temperature (C) 9 B 8.8 8.6 8.4 A 8.2 8 3.5 Leaf Litter Depth (cm) 9.2 7.8 3 2.5 2 1.5 1 0.5 7.6 0 7.4 Core Trail Core Road Trail Road Figure 5: Differences in abiotic data collected at core, trail, and road sites. A: Average soil temperature (C) recorded at each site type B: Average leaf litter depth (cm) collected at each site type. The A and B labels show significance between the Core, Trail, and Road in respect to soil temperature. Regression plots comparing net distance traveled (Figure 6), total distance traveled (Figure 6), and linearity (Figure 7) to the recorded abiotic factros revealed R2 values below one. This data presents no statistically significant pattern between abiotic factors and movement of Red-backed salamanders. Note that both net distance and total distance travled had positive correlations with increase in percent canopy cover and increase in soil temperature. Both movmenet behaviors had negative correlations with number of cover objects and leaf litter depth. 12 A B 300 300 250 250 200 200 Total Distance Moved (cm) Total Distance Moved (cm) 150 R² = 0.1718 Net Distance Moved (cm) R² = 0.0899 Net Distance Moved (cm) 100 R² = 0.0972 150 100 50 50 0 0 0 2 4 6 0 20 Leaf Litter Depth (cm) C D 300 80 100 250 200 200 Total Distance Moved (cm) 150 R² = 0.1428 Net Distance Moved (cm) 60 300 250 Total Distance Moved (cm) 40 Percent Canopy Cover R² = 0.0592 Net Distance Moved (cm) R² = 0.077 100 R² = 0.0757 150 100 50 50 0 0 0 50 100 150 200 250 0 5 Number of Cover Objects 10 15 Soil Temperature (C) Figure 6: Regression plots examining the relationship between leaf litter depth (cm) (A), percent canopy cover (B), number of cover objects (C), and soil temperature (Celsius) (D) versus total distance and net distance moved by each Red-backed salamander followed into the ground. 0.9 0.9 0.8 0.8 0.7 0.7 0.6 0.6 0.5 0.5 0.4 Linearity 0.3 R² = 0.0088 0.2 0.4 Linearity 0.3 R² = 0.017 0.2 0.1 0.1 0 0 0 1 2 3 4 5 6 0 Leaf LItter Depth (cm) Linearity R² = 0.2587 20 40 60 80 100 Percent Canopy Cover 0.9 0.9 0.8 0.8 0.7 0.7 0.6 0.6 0.5 0.5 0.4 0.2 0.4 Linearity 0.3 R² = 0.001 0.2 0.1 0.1 0.3 0 0 0 50 100 150 200 250 0 Number of Cover Objects 5 10 15 Soil Temperature (C) Figure 7: Regression plots examining the relationship between leaf litter depth (cm) (A), percent canopy cover (B), number of cover objects (C), and soil temperature (Celsius) (D) versus linearity of each Red-backed salamander followed into the ground. Discussion 13 Studies have shown large dominant male Red-backed salamanders stake the most “ideal” habitat and the territory size is congruent with the size of the individual (Holman, 2012; Mathis, 1991). It may be that these larger individuals are monopolizing core habitat forcing juveniles, who tend to have little or no territoriality, out to the less hospitable road habitat (Jaeger et al., 1995). In other words, decreased movements within road side habitats could occur due to the potentially more prominent presence of juveniles. Cosentino & Droney (2016) found costly tradeoffs between movement and desiccation. Juveniles, who are at a greater risk of desiccation because of their bodies low surface area to volume ratio, in these areas compared to larger territorial individuals that reside in core habitats, may be moving lesser distances overall because of their increased risk of drying out (Grover, 1998; Cosentino & Droney, 2016). This displacement of juveniles to poor quality habitat could have effects on both the organism’s and ecosystem’s health. There is an increased fitness provided to individuals who have prominent home ranges, but staking these home ranges requires energy. Total distance and net distance moved were longer at core sites and shorter at road sites in this study. Evidence of home ranges following similar patterns have been seen in clear cut habitats versus core habitats in a study by Marsh & Beckman (2004) The trade-off of asserting dominance over a home range energetically pays off, but some smaller individuals or those in non-hospitable habitats may be unable to expend the initial costs it would take to establish a large home range (Jaeger, 1981). Diminished home ranges within road site habitats would have negative biological effects. A study completed in New Hampshire found that terrestrial salamanders with limited home range showed a significantly decreased contribution to the nutrient cycling of forests floor ecosystems (Burton & Likens, 1975). Nutrient cycling is one of the major ecological roles that terrestrial salamanders play in the ecosystem; without their contribution, the productivity of the system would decrease. A possible factor contributing to the displacement of the subservient individuals by those that are dominant could be prey competition. There is a large food niche overlap between juveniles and adults. It is presumed that P. cinereus is a superior competitor of food in soil compared to other terrestrial salamanders; this could potentially be the same for adult versus juvenile Red-backed (Jaeger, 1972). Previous studies have used activity as a relative measure for foraging of terrestrial salamanders (Jaeger 1978, 1980; Pough et al., 2004). Although, amount of prey within each fragmentation type was not recorded during this study, greater movement, like that documented within core sites, could indicate an increase in foraging efforts, so a lower prey 14 abundance. This lower prey abundance could have contributed to larger individuals edging out small juveniles. It would follow that individuals moving short distances along fragmented habitat were doing so because they had sufficient prey and did not need to leave the safety of moist refuge to forage. Although, as habitats are degraded Fraser (1976) projected that competition for food items may increase forcing organisms to expend more energy searching for prey but that is not what was observed in my study. A future study could examine if prey abundance increases with degraded forest habitat at Woodcock Creek Lake Park in comparison to sites with no fragmentation to determine if food competition is a factor impacting movement. Movement on the forest floor increases vulnerability to predation (Jaeger, 1978). The decrease in both total and net distance moved along road habitats may also be explained by the increased predation characteristics associated with forest fragmentation and edge effects(Murcia, 1995; Marsh & Beckman, 2004; Turton & Freiberger, 1997). This could be tested by documenting the automized tails of individuals captured to quantify attempted predation risk (Roberts & Liebgold, 2008). Numerically, trail sites had more leaf litter and medium canopy cover which may allow individuals residing there to avoid the desiccation that would normally threaten them due to the increased soil temperatures seen at this type of fragmentation in this study. Red-backed salamanders may be able to move out from under refuge because a high number of cover objects shade and maintain cool temperature retreats. Leaf litter and cover objects also hold moisture well, decreasing risk of drying out (Woolbright & Martin, 2014). These habitat characteristics could enable Red-backed salamanders residing near trail fragmentation to consistently travel short distances over multi-day periods, allowing longer net distance movements that mitigate the negative effects of fragmentation on total distance moved. This is also supported by the negative relationship seen in this study between both movement variables and leaf litter depth (cm) and both movement variables and number of cover objects. The lack of correlation in this study between movement patterns including total distance moved, net distance moved, and linearity, in correlation to abiotic edge effects of percent canopy cover, number of cover objects, and leaf litter depth aligns with the consistently concluded idea that ability to retain water, and therefore soil moisture and temperature, is the major characteristic influencing Plethodontid movement. As stated earlier, soil moisture has been shown to be a key characteristic affecting Red-backed salamander population and latency (Marsh 15 & Beckman, 2004; Yeager 1980) and studies suggest that soil moisture is most likely a key determinant of movement as well. Others state that cool soil temperatures have more of an impact on movement behavior due to its larger role in potential desiccation (Rothermel & Luhring, 2005; Keen, 1984). Although this study did not find any correlation between soil temperature and either net distance or total distance traveled, it demonstrated that temperatures were significantly higher along road sites versus both core and trail sites. This temperature difference aligns with net movement, where road fragmented sites showed decreased net displacement when compared to trail and core habitat. These findings, in conjunction with the confounding literature suggest soil temperature and soil moisture are important aspects that needs to be studied further in future research when examining movement behavior. Red-backed salamanders are found to be either absent from the habitat or remain within soil to maintain amiable temperatures when soil temperatures are below 5 or above 25 degrees Celsius (Taub, 1961). Within this study, soil temperatures remained within the range of known abundance with week relationship found between movement variables and soil temperatures. This may be due to the fact that temperatures were recorded during the day and not at night, when temperatures are likely to drop. This is also when Red-backed salamanders are most active. Nighttime soil temperatures could have a stronger correlation with the movement variables than daytime due to the nocturnal nature of this terrestrial salamander. A weakness of this study was the time constraint resulting in an incapability to record soil moisture. From observations made in the field, habitat near road fragment appeared to have severely inconsistent moisture levels. Following bouts of rain, edge habitat retained excessive amounts of soil moisture, with puddling in areas for over 24-hour periods while sites within forest appeared to steadily wet and drain. RBS cannot forage in extremely dry soils nor can they do so in inundated soils (Taub, 1961). Soil moisture noted along road side habitat (dry to overtly saturate) inhibits salamander movement which aligns with this study’s findings of decreased movement along fragmentation and increased along core habitat. In future studies, soil moisture should be documented to test correlation between movement variables. It was believed individuals would avoid traveling in the direction of fragmentation due to its assumed degraded habitat quality. Physical characteristics associated with fragmentation create an unfavorable habitat for terrestrial salamanders decreasing abundance among fragmented habitat, specifically, volume of cover objects, soil temperature, percent canopy 16 cover, leaf litter depth, and soil moisture (Grove, 1998; Bobka et al., 1981). Within this study, there was a lack of variation in percent canopy cover, cover objects, or leaf litter depth between treatment types. The consistent quality of these characteristics may prevent organisms from delineating among fragmented and non-fragmented areas within Woodcock Creek Lake Park. Habitat alterations associated with fragmentation were not strongly differentiated so individuals are not avoiding fragmentation during short term movement. Long term movement studies, covering multiday periods, sampling at increasing distances from fragmentation may express the typical gradient of increasing abiotic factors away from fragment and a net movement away from fragmentation (Chen et al., 1995). One of the largest limitations of this study was the inability to identify individuals as recaptured. It is unknown whether the same organisms were captured each time the site was visited or if new salamanders were found and pigmented each time. Knowing this could provide multi-day movement data of individuals as well as verify or expand the sample size of the study. This type of knowledge should be addressed in future research. A noninvasive technique to do this is through computer vision software. Through photographs taken of the salamanders as they are found, the software will allow researchers to identify Red-backed salamanders by their specific coloring and markings. Computer identification was attempted during this study although it was unsuccessful at identifying individuals. In the future for greatest success, salamanders should be rinsed using either rain or DI water and then placed in a shadowed boxed to prevent glare from the sun. By standardizing the background each photo is taken and the camera it is take with, the percent error of this computer vision software greatly decreases. This is an extremely user friendly software proven to be ideal for the sample sizes of this type of study (Gamble et al. 2008). A future study branching from results found at Woodcock Creek Lake Park would continue to look at the impact forest fragmentation has on Red-backed movement using fluorescent pigment powder. Photo ID software would be used to identify individuals and collect information about home range size in addition to movement data. Soil moisture and soil temperature would be documented as well as snout vent length and total length. This would help determine if adults are more common in the core habitat and if juveniles are potentially more abundant near fragmented habitat. 17 Conservation With the impact that fragmentation has on Red-backed salamander movement patterns, it is likely that this fragmentation will affect the movement of specialist species who typically have a limited habitat and low tolerance to altered environmental conditions (Scheffers & Paszkowski, 2012). Because of the risks associated with fragmentation for terrestrial salamanders, protection of road-less areas is an important and effective conservation strategy (Semlitsch, 2000; Blaustein et al., 2000; Gucinski et al., 2001). Protected areas have more road less spaces with less habitat fragmentation. To preserve terrestrial salamanders, protection of areas like Woodcock Creek Lake Park is both vital and most effective since these areas already have larger un-inhibited habitats compared to other public and private lands (Haddad et al., 2015; Gucinski et al., 2001). It is important to note that during this study it was difficult to find patches of habitat greater than or at least eighty meters apart, which is the furthest distance edge effects are determined to affect for this species. Research had to extend out to nearby state game lands to find additional uninterrupted core sites with eighty meters of buffer on all sides. Woodcock Creek Lake Park is a protected area and even then it was challenging to find habitat that was not effected by some degree of fragmentation. This trend has been seen in other national forests identifying a need for stringent protection of these areas (Gucinski et al., 2001). It has been suggested that traffic density plays a large role in the impact of edge effects for organisms (Fahrig et al., 1995; Hels & Buchwalk 2001; Mazerolle, 2004). Woodcock Creek Lake Park is a relatively low traffic zone, with less than 15,000 visitors during peak summer season. The impacts of forest fragmentation on Red-backed movement may be increased and exacerbated during peak season and movement may be more affected at larger well-known parks that attract a greater amount of activity. These two findings combined suggest that the current conservation of road less areas in national parks, even though it is greater than non-protected lands, is still not sufficient. Management practices should focus on creating road ways and hiking trails that maximize the inner forest habitat between anthropogenic transportation pathways to decreases the amount of fragmentation and net impact of traffic density on edge effects associated with forest fragmentation. This study supports the claim that habitat destruction and fragmentation negatively impacts movement of Red-backed salamanders. This coupled with their declining populations and lack of abundance along fragmented habitat, both documented in the literature, demonstrates their need to be a focus of conservation. Decreasing the number of individuals within these areas 18 as well as limiting the range they affect within their habitat could impede the keystone predatory role they play in the forest floor ecosystem. Terrestrial salamanders mainly feed on soil micro fauna and invertebrates. 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