We have been hard at work testing some new designs and combinations of materials to find affordable and effective solutions for turtle tunnel systems in Ontario's Highlands. Read about our pilot work here: TT Report (2)
Turtle Route Fidelity, by Kiara Duval - November 2021
Edited by: Andrea O’Halloran and Leora Berman
Researchers have found that turtles are creatures of habit when it comes to seasonal activities. Though it is very species-dependent, the majority of turtles display some sort of fidelity (faithfulness) to their home regions. That is, they return to the same areas for various activities year after year. Studies have shown that some species of turtles have fidelity to nesting, overwintering, and foraging sites (Schofield et al., 2010; Casale et al., 2007). For a specific example, painted turtles have been observed to show fidelity to nesting areas (Roth and Krochmal, 2015). There is also another type of fidelity that turtles exhibit: route fidelity. This is defined as loyalty to migration routes used to travel between various habitat types. However, route fidelity in turtles is not as well-studied as the other types of fidelity.
Studies focused on migration routes are important for many ecological and conservative reasons. Understanding a population's distribution and habitat requirements allows us to better understand how to protect species and support their conservation (Schofield et al., 2010; Siegwalt et al., 2020). The long-term viability of different species can be directly impacted by environmental processes, human activity, and many other factors (Schofield et al., 2010). Predicting nesting sites, migratory pathways, foraging sites, and over-wintering sites are some of the main priorities when it comes to the turtle conservation effort (Broderick et al., 2007). Knowing when and where turtles spend their time can help us to understand where protection efforts are needed. These efforts can also help us to realize the effects human activities can have on their critical habitats (Casale et al., 2007). Understanding the level of fidelity that turtles have to their migratory routes when traveling between foraging, nesting, and overwintering sites is key to discerning where to focus conservation efforts (Broderick et al., 2007). For example, assessing where painted turtles nest, as it is close to the same area yearly (Rowe et al., 2005), would allow us to protect this nesting area more effectively. However, this is not as easy to assess as it may seem.
Predicting population distribution of turtles has always been difficult due to their elusivity and extensive home ranges (Horton et al., 2017). For example, Snapping Turtles have been observed to follow their migration routes very carefully, although they do periodically change their preferred sites (Keevil et al., 2018). However, there is hope for these studies with the advancements of modern technology, such as satellite tracking, which has made it possible to remotely track an animal's movement (Horton et al., 2017). This allows researchers to analyze trajectories and pinpoint patterns of navigation that different individuals use year after year (Horton et al., 2017). By being able to point out these migratory corridors, researchers can make recommendations for mitigation strategies for these regions. For example, monitoring or controlling fisheries activity during the turtle's migratory season can have a substantial impact on turtle conservation, as shown in a study done by Boderick and colleagues (2007). They showed that Green and Loggerhead sea turtles spent a lot of time resting on the seabed, making them highly susceptible to demersal (groundfish) fishing gear (Broderick et al., 2007).
The results of turtle route fidelity studies have been somewhat inconsistent. That is, there appears to be a great deal of variability in route fidelity, especially among different species of turtles. To demonstrate this, I will present examples from a few different studies.
First, for sea turtles: in a study by Schofield and contributors (2010), the movement of male Loggerhead Sea Turtles was tracked. Though these turtles did return to their original foraging sites each year, they did so by using a myriad of different routes. In a different study conducted on female Hawksbill Sea Turtles, Hawkes and contributors (2012) showed there was not always strong fidelity to migratory routes, and that routes varied in some cases by hundreds of kilometers. However, strong nest and foraging site fidelity was still observed (Hawkes et al., 2012). Further, Boderick and her colleagues (2007) were able to demonstrate some route fidelity in female Green Sea Turtles and Loggerhead Sea Turtles when examining post-nesting migration to foraging grounds. These turtles were tracked for many years and used highly similar routes to return to their foraging and over-wintering areas.
The results are a bit more regular for freshwater turtles where studies demonstrate more definitively that some species may use the same routes to get to their overwintering sites. This appears to be the case for the European Pond Turtle studied by Thienpoint and colleagues (Thienpont et al., 2004). In another study performed on Painted Turtles, a native Ontario species, incredible route precision when returning to sites was observed year after year (Ross and Krochmal, 2015).
Overall, however, there is still uncertainty in the literature with regards to turtle migratory route fidelity. However, all the information presented here was taken from studies where route fidelity was not the main focus. This highlights the need for future studies to focus specifically on turtle migratory route fidelity. This will further inform the need for conservation efforts focused specifically on turtle migration routes.
Fidelity patterns in turtles can be very important for their prolonged survival. They can also be highly variable between different species. As you may already know, many turtle species travel incredibly long distances, both by water and over land, between the sites they use for various life activities including hibernation, mating, and feeding (Shimada et al., 2020; Thienpont et al., 2004). You might be wondering: why would they spend so much time and energy going back and forth to the same spots every year? To answer this question, we will look at a few different factors.
Firstly, maintaining fidelity to specific sites is considered by many to be a low-risk strategy (Schofield et al., 2010). The turtles know that specific sites have provided them with the resources they needed in the past, and this offers them security (Schofield et al., 2010). This means that returning to a site that they’ve used previously can be much more beneficial than searching for a new, unexplored site. Most turtles will return to the same foraging sites every year and only stray if their existing site has suffered degradation and is no longer profitable (Schofield et al., 2010). Studies have also shown that both locally raised and newly released turtles show site fidelity to the area where they were released or born (Attum et al., 2013). The released turtles in particular might choose to remain in the area of their release, as this is the area that becomes familiar to them. Other factors that could impact a turtle’s fidelity to a particular site could also be related to familiarity accompanying easier defense of the territory, or the quality of the site (Broderick et al., 2007).
Turtles are incredible animals with very interesting, if variable migratory patterns. The ability of some species to pinpoint specific locations over hundreds of kilometers and return to them is a fascinating subject to many researchers. Knowing what sites they favor and when they are likely to return can facilitate our studies and present opportunities to learn more about them. Being able to study these patterns will not only increase our understanding of their behavior, but will also allow us to better guide conservation efforts to protect native turtle species.
By: Andrea O’Halloran - December 2021
Harsh Ontario winters present unique problems for non-migratory animals. Ectotherms, such as freshwater turtles, need to employ strategies to avoid freezing while living in cold conditions for extended periods of time because the external temperature determines their body temperature. There are two strategies turtles are known to use to survive severe winter conditions: freeze avoidance and freeze tolerance (Cantrell et al., 2014). Freeze avoidance is considered a behavioural strategy. Turtles will spend the winter below the water surface, in areas where temperatures do not dip below freezing, to avoid ice penetration (the entry of ice crystals from the environment into their body) (Costanzo et al., 2008; Valerio et al., 1992). All adult freshwater turtles in Ontario do this. The second strategy, freeze tolerance, is the ability to survive the physical freezing and thawing of one's body without injury or death (Costanzo & Lee, 2013). This strategy is known to be employed by Painted turtle hatchlings (Cantrell et al., 2014).
When overwintering in a body of water where the surface freezes over, oxygen availability is limited. To survive in these conditions, turtles need to find a habitat with stable oxygen supply and temperature, to which they show site fidelity (they return to the exact same sites year after year because they have these specific conditions). In addition, they shift to anaerobic metabolism. This is only practical during overwintering because metabolic rates are extremely slowed during this process, and require very little energy. However, anaerobic metabolism causes increased lactic acid production and depletion of glycogen stores, which can threaten the survival of an overwintering turtle (Cantrell et al., 2014). Additionally, oxygen dispersal (availability) is not uniform throughout the water column, so a turtles’ position in the body of water has significant effects on physiological processes such as metabolism and respiration (Cantrell et al., 2014).
Adult turtles are known to adjust their position in the water, despite choosing the same sites each year (hibernation site fidelity), in order to avoid freezing temperatures (Bodie & Semlitsch, 2000) and to minimize acidosis (excess acid present in body fluids) (Greaves & Litzgus, 2008). Taylor and Nol (1989) observed multiple occasions where three Painted turtles readjusted their positioning after ice formed over their overwintering pond. They also found that an individual moved within the water column to an area of higher oxygen availability when the environment became anoxic (void of sufficient oxygen levels), suggesting that turtles, despite their vulnerability and slowed movements are capable of relocating from a low to high quality area within their dedicated hibernation site, however, scientists did not observe such adjustments (of greater than 1 m) after ice cover developed over the water bodies (Edge et al., 2009). Unfortunately, hatchlings and juveniles tend to occupy shallower overwintering grounds and readjust less often than adults. Because young turtles are less able to adjust to changing conditions, they are sometimes unable to respond accordingly, and do not survive through the winter (Bodie & Semlitsch, 2000). Some hatchlings are able to forgo the dangerous search for an ideal overwintering location and instead wait out the winter in their nest cavity (Ultsch, 2006); Painted turtle hatchlings are known to employ this freeze tolerance strategy (Cantrell et al., 2014), while snapping turtles are not known for this adaptation. Adult turtles also have a bit of an edge over juveniles, as their shells are a source of calcium which act to remove some lactic acid build up during hibernation, while hatchlings don’t have the same advantage (Ultcsh, 2006).
However, there are other reasons for adult turtle mortality in winter such as anoxia (the loss of oxygen), predation, freezing temperatures (Ultcsh, 2006), and immunosuppression (Refsnider et al., 2015) where, because temperatures determine both metabolic processes and immune system function, turtles may succumb to disease or infections during hibernation. Surprisingly, however, winter turtle mortality rates are lower than mortality rates in spring and summer.
The ability for a species to survive in an environment with very low oxygen availability is called anoxia-tolerant. Different species of turtles have varying degrees of tolerance/intolerance; some turtles are anoxia-intolerant, while others are anoxia-tolerant. For example, Western Painted turtles are considered the tetrapod with the best anoxia-tolerance, while Map and Wood turtles are considered anoxia-intolerant. For this reason, Map and Wood turtles are known to select hibernation sites where dissolved oxygen is elevated and the water surface does not completely freeze over (such as flowing streams and lakes) (Cantrell et al., 2014); These environments allow them to maintain aerobic respiration while hibernating (Reese et al., 2002). Anoxia-intolerant turtles need to overwinter in an area with a higher partial pressure of oxygen, which would restrict the number of overwintering sites a turtle can occupy.
Regardless of the level of tolerance a species has to low oxygen conditions, all turtles are immuno-supressed during the winter, and also are unable to use their lungs to acquire oxygen during hibernation, and instead, will use either their cloaca (end of digestive tract) or skin for respiration (Edge et al., 2009).
Hibernation site fidelity (the returning to the same hibernation sites annually) is high for both anoxia tolerant and intolerant turtles, because the site must have very specific conditions for overwintering. Therefore the conversion, contamination, or loss of small wetland habitats and shoreland areas threatens turtle survival and therefore the success of future generations. Without access to crucial habitats, turtles are unable to survive the cold winter months. A lack of information and attention to these areas, and increased land development means that turtles will have little hope moving forward.
Another threat to overwintering adults is predation; in a study of intact hibernation sites conducted by Brooks and colleagues (1991), it was found that the majority of turtles that did not survive the winter were casualties of predation. This was deduced because turtle carcasses that were found were mutilated and had wounds indicating that they had been attacked by a predator. Predation is a threat to turtles in the spring as well; when emerging from overwintering grounds, turtles are at an elevated risk of predation because hypoxia (insufficient oxygen available for body tissues) (Newton & Herman, 2009) and related metabolic acidosis which make them sluggish and slow moving. They are therefore less able to avoid predators at this time by fleeing (Greaves & Litzgus, 2007). Again in the late autumn before ice over, turtles are again at an increased risk of predation (Greaves & Litzgus, 2007). During this stage, the water’s temperatures are low and therefore turtles are less able to mobilize; the cold initiates a torpor (inactivity) state (Newton & Herman, 2009).
Another threat to the health of turtles during hibernation is immune system depression which is exacerbated by low energy reserves. Again, when emerging from overwintering grounds there can be a delay in the immune system “rebooting” as this depends on body temperature. At this time turtles will be more susceptible to infection. In an overwintering study, Brown & Brooks (1994) found that of the four turtles that died after emergence, two of them had succumbed to bacterial infections most likely due to their lowered immune function.
The vulnerability of turtles due to cold temperatures is an issue of growing concern as climate change affects seasonal temperatures, and where unusual temperature fluctuations are becoming more common. Therefore, the chances of a turtle emerging early (when ambient temperatures are too low to kick-start immune function) are increasing, and especially as the spring migration to return to home ranges elevates a turtle’s exposure to risks of infection. Furthermore, the undulating weather patterns in late autumn also make the onset of freezing temperatures dramatic and erratic. (Refsnider et al., 2015).
Ontario turtles face many challenges including habitat loss, contamination, and alterations; and anoxia, predation, and immune suppression when overwintering. Identifying and conserving critical hibernation sites is essential for turtle survival. Understanding the effects habitat destruction and climate change on turtle overwintering sites and behaviours, especially here in The Land Between bioregion (the northern range of many species’ habitats) will have important influence on conservation strategies to protect turtle overwintering areas and turtle populations as a whole (Litzgus et al., 1999).
Sources:
Bodie, J. R., & Semlitsch, R. D. (2000). Size-specific mortality and natural selection in
freshwater turtles. Copeia, 2000(3), 732-739.
Brooks, R. J., Brown, G. P., & Galbraith, D. A. (1991). Effects of a sudden increase in natural
mortality of adults on a population of the common snapping turtle (Chelydra serpentina).
Canadian Journal of zoology, 69(5), 1314-1320.
Brown, G. P., & Brooks, R. J. (1994). Characteristics of and fidelity to hibernacula in a northern
population of snapping turtles, Chelydra serpentina. Copeia, 1994(1), 222-226.
Cantrell, E. A., Dong, C. M., Hill, C. A., & Warren, D. E. (2014). Buoyancy control in
cold-submerged painted turtles: implications for overwintering physiology and behavior. Herpetologica, 70(4), 388-394.
Costanzo, J. P., & Lee Jr, R. E. (2013). Avoidance and tolerance of freezing in ectothermic
vertebrates. Journal of Experimental Biology, 216(11), 1961-1967.
Costanzo, J. P., Lee Jr, R. E., & Ultsch, G. R. (2008). Physiological ecology of overwintering in
hatchling turtles. Journal of Experimental Zoology Part A: Ecological Genetics and
Physiology, 309(6), 297-379.
Edge, C. B., Steinberg, B. D., Brooks, R. J., & Litzgus, J. D. (2009). Temperature and site
selection by Blanding’s Turtles (Emydoidea blandingii) during hibernation near the species’ northern range limit. Canadian Journal of Zoology, 87(9), 825-834.
Greaves, W. F., & Litzgus, J. D. (2007). Overwintering ecology of wood turtles (Glyptemys insculpta) at the species' northern range limit. Journal of herpetology, 41(1), 32-40.
Greaves, W. F., & Litzgus, J. D. (2008). Chemical, thermal, and physical properties of sites
selected for overwintering by northern wood turtles (Glyptemys insculpta). Canadian
Journal of Zoology, 86(7), 659-667.
Litzgus, J. D., Costanzo, J. P., Brooks, R. J., & Lee, Jr, R. E. (1999). Phenology and ecology of
hibernation in spotted turtles (Clemmys guttata) near the northern limit of their range. Canadian Journal of Zoology, 77(9), 1348-1357.
Newton, E. J., & Herman, T. B. (2009). Habitat, movements, and behaviour of overwintering
Blanding’s turtles (Emydoidea blandingii) in Nova Scotia. Canadian Journal of Zoology,
87(4), 299-309.
Refsnider, J. M., Palacios, M. G., Reding, D. M., & Bronikowski, A. M. (2015). Effects of a
novel climate on stress response and immune function in painted turtles (Chrysemys picta). Journal of Experimental Zoology Part A: Ecological Genetics and Physiology, 323(3), 160-168.
Reese, S. A., Jackson, D. C., & Ultsch, G. R. (2002). The physiology of overwintering in a turtle that occupies multiple habitats, the common snapping turtle (Chelydra serpentina). Physiological and Biochemical Zoology, 75(5), 432-438.
Taylor, G. M., & Nol, E. (1989). Movements and hibernation sites of overwintering painted
turtles in southern Ontario. Canadian Journal of Zoology, 67(8), 1877-1881.
Ultsch, G. R. (2006). The ecology of overwintering among turtles: where turtles overwinter and its consequences. Biological reviews, 81(3), 339-367.
Valerio, P. F., Kao, M. H., & Fletcher, G. L. (1992). Fish skin: an effective barrier to ice crystal
propagation. Journal of Experimental Biology, 164(1), 135-151.
A great article to understand what, why, and how...https://academic.oup.com/bioscience/article/50/8/653/243214
DYK- ALL TURTLES IN ONTARIO ARE PROTECTED UNDER LAW
All turtles in Ontario are protected under legislation. Turtle populations are at risk of extinction and are considered “Species at Risk” in Canada, which means each turtle is important to maintain populations. Turtles are protected under the Fish and Wildlife Conservation Act, Endangered Species Act, the federal Species at Risk Act, and turtle habitats may also be protected under these pieces of legislation as well as municipal laws in most jurisdictions.
Direct harm to a turtle and also to their habitat features can carry fines of up to $25,000 or one year in jail. If someone kills a turtle, removes it from the wild or removes turtle eggs; or if someone buys or sells a turtle or their eggs, fines can be as much as $100,000.
If you witness a turtle being harmed, or if you see evidence of poaching, take pictures or videos of the incident if possible and if it is safe to do so. It is helpful to have proof of the harm or which documents the intent to harm a turtle, and therefore pictures or video footage can be vital to a case.
On roads it may be difficult to avoid turtles, however, if you see a vehicle swerve to hit a turtle that is on a yellow or white line, or a turtle on the road shoulder,, or if there are few vehicles on the road and the car has ample opportunity but still doesn’t avoid the turtle, these situations can be evidence of intentional harm. In these cases, get the license plate of the vehicle involved.
At the time of the incident, call 911, or if you have evidence of an infraction but are not on the scene, you can call Ontario’s conservation officers at 1-877-TIPS-MNR (847-7667). If you wish to remain anonymous, you can also call Crime Stoppers at 1-800-222-TIPS (8477).
Please remember to be cautious and do not approach if you feel unsafe. Also do not trespass on private property to gather evidence. Instead call one of the hotline numbers and stay turtley cool and turtley safe too!
Turtle species across Ontario are under threat, and it’s up to us to save them
Turtle species across Ontario are facing multiple threats to their survival. The two biggest threats are habitat loss and road mortality.
Many of their habitats, like marshes and swamps, have been altered by humans.
“So, in terms of what we’re seeing, of course, in especially in the last four years, is land conversion at a rate that has been unprecedented without sufficient planning tools,” said Leora Berman, Chief operating officer for the conservation organization The Land Between.
The Land Between is a bioregion extending from Ottawa Valley to Georgian Bay. It is home to 1/3 of Ontario’s turtle population and has seven to eight of Ontario’s turtle species. The Land Between is the last refuge for many turtles.
All eight turtle species in Ontario are classified as “species at risk.” Many are classified as endangered.
“Over 70% of wetlands in southern Ontario have been lost over the past century. This has removed the required habitat for many turtles and many other species of wildlife,” said David Seburn, Freshwater Turtle Specialist at the Canadian Wildlife Federation.
Wetlands are crucial for the survival of turtles and other important species.
Sadly, southern Ontario has the highest density of roads, which results in turtles getting run over by cars. Road mortality, along with habitat loss and other factors, contributes to the 50% decline in Ontario’s turtles.
Experts say if we lose another 20% of snapping turtles, they could be extinct in twenty years.
Around the time Grace was born, Ukrainian scientist Wademar Haffkine had just created a vaccine in record time to combat bubonic plague and was testing it on himself, the first human trial in history.
As Grace took her first steps in the world, future prime minister Lester B. Pearson was born and Queen Victoria became the first monarch to mark 60 years on England’s throne. Dracula by Bram Stoker was published and Thomas Edison’s kinetoscope device that produced moving pictures was patented.
Grace is older than any living human being, which makes sense because she’s a snapping turtle. The species can live over 275 years and, based on the size of her shell, Grace is at least 125 years old. She lives in Haliburton County, Ont., in a wetland next to three lakes, a hospital, a high school and an elementary school.
Hibernation is commonly observed in many species of animals, especially those inhabiting Northern regions where there are significant drops in temperature during the winter months. In Ontario, freshwater turtles are ectotherms (their internal temperatures mimic the external temperatures) which make them “unequipped” to directly face the ruthlessness of winter conditions. For this reason, they stow away in the winter to avoid the unfavourable conditions of the colder months. Scientists have found that some turtles overwinter close together in groups, and this practice is called communal hibernation (Edge et al., 2009; Litzgus et al., 1999; Brown & Brooks, 1994).
Communal hibernation is thought to have many benefits, but not in the way you’re used to hearing about. As ectotherms (where their temperature is determined by their environment), huddling together does not provide individuals with a rise in body heat like it does for endotherms such as humans and even penguins who may gather together for warmth (Duncan, 2016). Rather, the benefits of gathering together present themselves in less obvious ways. Some of these benefits include using group “signals” which would increases the chance of leaving hibernation sites at the same time (Litzgus et al., 1999), or as signifiers for a safe place to go when available hibernation sites become a limited resource (Greaves & Litzgus, 2007). Group hibernation may however, simply be a result of a group of individuals having overlapping home ranges (Edge et al., 2009). But there are some indications that there is more to this story:
Interestingly, aggregations at overwintering sites are more common in Northern ranges. This observation indicates that overwintering areas may, in fact, be a limiting resource to turtle survival there and that may be why turtles overwinter in groups (Newton & Herman, 2009).
Additionally, increased mating opportunities are thought to result in congregations of turtles. People may think that turtles mate in the early spring before nesting season begins. While this can be the case, turtles also perform courtship and mating at overwintering sites late into the fall before stowing away from the cold. This is possible for most turtle species (Pearse & Avise, 2001) because most females can physically store sperm in their bodies for future use (Environment Canada, 2015). In turtles, tubules in the oviduct that are specialized to store sperm are generally observed, indicating that this may be a common component of their reproductive behaviour (Pearse & Avise, 2001). Repeated paternity was commonly found in a study on Blanding’s turtles, displaying that females could use stored sperm over subsequent years from the same male to produce her eggs (Henning & Hinz, 2016). Amazingly, there have been instances where female turtles in care (captive turtles) have been isolated from males, and yet, astonishingly, the females continue to produce offspring (Pearse & Avise, 2001). Therefore, hibernating where other turtles are found has advantages; the increased likelihood of finding a mate! Should a female be unable to find a mate in the spring, she can find a mate in the winter, and still successfully lay eggs during the nesting season using stored sperm (Carrière et al., 2009).
Another benefit: males generally move great distances during the typical spring mating season to seek out females (Buchanan, 2017). However, if males mate at overwintering sites, they are less motivated to seek out mates and thus, able to spare energy during this active season, because, at times, female mates may be hard to find. Therefore, communal overwintering also allows a male turtle to save energy and yet increase success, by mating at the same site he overwinters (Carrière et al., 2009).
In a study investigating hibernation site selection of Blanding’s turtles, Christopher Edge and collaborators (2009) discovered multiple Blanding’s turtles copulating and hibernating together (≥ 5m) in Algonquin park. At these sites, groups of turtles ranged from two to seven individuals, with both sexes present in all scenarios. This could suggest that communal areas are promoted by the mating opportunities related to grouping together, or it may simply be because habitat destruction has limited the number of overwintering sites available for the population (Edge et al., 2009).
In a study conducted to investigate courtship and mating behaviours of Northern Map turtles, results suggested that communal hibernation was widely displayed in this population. In Lake Opinicon, 75% of studied males ventured near two popular turtle overwintering sites throughout the course of the study. The scientists were able to track the movement of these individuals using radio-telemetry. This tool uses radio signals and transmitters attached to animals (in the case of turtles it is typically attached at the rear-end of their shell) (Litzgus et al., 1999)) to observe their movement while off site. The data did not indicate what percent of males successfully completed overwintering at these sites. However, the results suggest that the majority of males in the area do travel close to communal sites to reap the benefits of group mating (Bulté et al., 2021).
Alternatively, in a study on Wood turtles conducted in Sudbury, Greaves and Litzgus (2007) did not find any evidence to support the idea that turtles overwinter in groups. This places some doubt on the general view that all turtles have a tendency to behave this way. The study was run using visual observation and tracker data. Although the general consensus was that turtles did not overwinter in groups, a pair was documented mating at the overwintering sites before separating for the winter. This supports the idea that turtles may use opportunistic fall mating interactions to increase their fitness (Greaves & Litzgus, 2007).
In Georgian Bay Ontario, a four-year hibernation study on Spotted turtles noted that communal hibernation was commonly found. The researchers again employed the use of radio-telemetry to track the locations of Spotted turtles over the years as well as visual observations to supplement this data. The primary purpose of this study was to assess the ecology and typical hibernation behaviours of Northern Spotted turtles. In the process the scientists also made other remarks. Of the eleven hibernation sites monitored, seven were found to be used for communal hibernation of turtles (≤ 9). This region is, however, considered to be the northern range of a Spotted turtles territory suggesting that this observation could be due to limited hibernation site availability, as previously discussed (Litzgus et al., 1999).
While hibernating in groups seems to have many upsides, this behaviour can nevertheless be dangerous for vulnerable subpopulations of freshwater turtles because grouping together can increase the risk of extirpation (a subpopulation being completely wiped out in an area). In cases where large groups of turtles come together, the increased activity can attract predators (Litzgus et al., 1999). Related is that during the winter, turtles are in a state of inactivity under the water because the low temperature causes metabolic depression and physiologically, metabolic depression limits an individual's ability to move (Newton & Herman, 2009; Edge et al., 2009). Therefore turtles cannot escape attacks by predators at this stage. These situations can be particularly detrimental to unstable subpopulations as it can result in a huge loss of reproductive adults, and potentially result in extirpation (Litzgus et al., 1999).
But also, habitat destruction or alteration can affect overwintering populations; The viability of typical overwintering sites can be changed and make that area unsuitable for overwintering (Litzgus et al., 1999). Examples include when wetlands and shorelands are “filled in '' or drained, or water levels are changed, most often, artificially. Typically, turtles select a pond or water body for overwintering, where there is the potential for a barrier to form between the turtle and the ambient air temperature. The barrier produces a comparatively warmer environment (Ross and Anderson, 1990). Some wetlands may be quite small with stable water levels, a thick warm substrate, also where a layer of ice may become the needed boundary between the water and the air. Without this stable underwater refuge, a turtle’s risk of desiccation and encountering freezing temperatures is significantly elevated (Markle et al., 2020). Unexpected changes in habitat conditions often result in indirect changes to the hydrological condition and water temperatures of the area (Bodie & Semlitsch, 2000) which then can result in many unintended deaths. Therefore, turtles grouping together for the winter, means that more individuals are vulnerable to negative events, and which may increase the chance of local extirpations. In other words, many adults can be killed off because of human alterations to habitats or during a particularly difficult winter (White, 2013).
It is accepted that communal hibernation is exercised by freshwater turtles, however, researchers have not concluded that it is employed in every turtle species. Future studies may aim to determine whether this phenomena exists reliably in all turtle populations, and should also aim to assess the patterns of this behaviour based on the spatial ecology of areas. Doing so, will help to inform attuned policies and improved conservation measures.
Generally, conservation of all hibernation areas (chiefly wetland habitats) is of the utmost importance because death of adult breeding turtles individually will destabilize local populations, but also where there may be communal groups, local extirpations of turtle populations is an immediate concern. As habitat areas and their quality are compromised by human activity, and as temperatures become more inconsistent due to climate change, the threat to turtle populations is an increasing reality for Ontario freshwater turtles. Human development with subsequent habitat loss may also increase communal hibernation, and then in addition to the vulnerabilities from more destruction or climate change, increased threat from predation events is added to the mix. For all these reasons, continued efforts to preserve wetlands and surrounding areas are vital to the protection and longevity of freshwater turtles in Ontario.
Written by Andrea O'Halloran, edited by Leora Berman and Kiara Duval
Sources:
This is a vulnerable time for turtles, not only because they are using less oxygen, but because their immune systems are also "on low" , and because, while they may need less oxygen, they still need consistent and reliable supplies of oxygen to stay alive through the winter. For these reasons, turtles often choose smaller wetlands or lakes where the water is filtered by lots of vegetation and where water levels are stable. These sites can be the most unremarkable areas and areas we least expect turtles to have chosen, but yet each site is extremely important to the survival of turtles- Also because turtles are loyal to their winter sites and return to within 1 metre of where they did the year before. Therefore, turtles cannot be "relocated" to new sites easily or at all, because adult turtles cannot readily make new memories of routes and places. If they are moved or if their chosen-wetland sites are lost, turtles are unlikely to survive away from their natural-given areas and territories. At The Land Between we have wonderful staff members and volunteers who dedicate their time to protecting the region’s turtles. Today I am going to give you a sneak peek into what a day in the life of a field technician looks like. It’s different every day, and the name of the survey game is flexibility!
What We Do:
Conservation technicians work in pairs 5 days a week and conduct road surveys and wetland surveys. Essentially, we are looking for turtles, frogs, and snakes. “Ewww” for most people, but fun for us because we are very dedicated to this work. For road surveys, we drive slowly along roads with high turtle mortality rates. When we are driving and come across a wetland, we will safely pull over and walk along that wetland looking for turtles, frogs, and snakes.
Start time:
Our survey schedule depends on weather and temperature. If it’s not raining, we start around 4:30. If it is a rainy morning then we will head out at 8 am and if it continues to rain throughout the day, we take a late afternoon break and then go out surveying again. Sometimes we have been out until 2 am with nesting turtles. These are very long days for us, but we know the work is important so we do it gladly. If the temperature reaches below 12 degrees turtles won’t be out so if a day is ever that cold, we usually spend it catching up on data entry or writing blog articles like this one.
What we do when we find a turtle:
If the turtle is on the road, we will pull over safely and then help it cross the road in the direction it was moving to…unless it is nesting. If nesting, when the turtle is finished she usually heads back to the wetland from where she came.
If the turtle is basking on the side of the road we will first make sure that it isn’t nesting. When a turtle is nesting you must never bother it because it could get spooked and might not finish laying.
If we find a nesting turtle, we will stay with it until it is done (Hence, the 2 am nights mentioned earlier.) Once the mother is done we will weigh and measure her and then excavate the nest. We have received specialized training in
excavation and TLB has permits to excavate nests.
Turtle processing:
When we find a turtle that is not nesting or finished nesting we will weigh them, give them a special name, measure the carapace (upper shell) and plastron (lower shell), then we take a photo with a special code including the turtles’ name, age/sex, action (i.e. basking/traveling), and the date of capture. We will also write 2021 on their plastron so we know if we ever get a recapture. If you ever find a turtle with 2021 on it contact us at The Land Between. Once we are done processing the turtle, we will release it back in the direction it was going but safely off the road- and again, it if was nesting, we help her to the wetland behind her. Otherwise, after the turtle is moved, we will watch the turtle until we are certain it isn’t going to head back onto the road.
Our staff is vigilant in sanitizing equipment between each turtle we process to ensure diseases won’t be spread.
Sometimes we get calls from members of the public when they see a turtle on the road or nesting and
if one of our teams is close by, they will head over to help.
Whenever we find a nesting turtle it is very exciting. Especially when it is a Blanding’s turtle since they are a more threatened species. If we find a turtle that has just started nesting it means we may be watching it for a few hours. The turtle needs to pick a spot they like, dig deep enough to lay her eggs, and then cover it back up. When the turtle is done laying, we will capture her and process her and then we will excavate the eggs. Turtle eggs are usually predated within the first 24 hours of laying. We excavate eggs in high risk areas such as roadsides or driveways, to help avoid predations, giving them a much higher rate of survival. Also because the hatchlings can be released where they were laid, but we can help ensure they can avoid being injured on the roads or eaten by predators by bringing them to the nearest wetland/water area.
Once a team has completed their route they will head back to The Land Between headquarters (if their route is close by) where we have an incubator set up to keep the turtle eggs. The eggs will be transferred carefully to a container with vermiculite, weighed, then put safely into the incubator. All data, including the nest ID, coordinates of the nest location, and details are recorded carefully.
Once the hatchlings start emerging in August, the team who excavated the nest has the privilege of releasing the hatchling back to the closest wetland to where they were found. Also, we call anyone who helped us save the nest to be witness to the release. So cute!
Every day is different. Some days may be slower and end at 10 pm and some may be longer and end at 2 am. We let the turtles determine that and we are good with that.
If you would like to learn more or become a Turtle Guardian you can visit the Turtle Guardian website here https://www.turtleguardians.com/the-land-between-ontarios-turtle-country/
Written by: Nadia Pagliaro, Conservation Technician