The spiny softshell turtle and the effects of habitat loss and fragmentation

The spiny softshell turtle (Apalone spinifera):

The spiny softshell turtle is often also referred to as the “pancake turtle” (2).  Using the first image above, I’m sure that you can understand how this nickname came about.  Their carapace is smooth, leathery and flat, which is atypical of most turtle species.  What’s especially cool about softshell turtles is that they rely, to some degree, on cutaneous respiration (1).  In other words, they can breathe through their skin!  This is a characteristic that is probably most recognizable with frogs and other amphibians, but now you know that turtles can do it too.  Another really neat, distinguishing feature of this “pancake turtle” can be seen in the second picture, which illustrates its pointy snout clearly.  If you want to see a spiny softshell in action, here is a brief video:


Credit YouTube user: nemastoma2
I plan to post several videos this week, so I would like to make one point very clear: I do not condone going out of your way to film these animals as such actions may cause disturbances.  I do not know how these videos were obtained, and I can only hope that they were filmed by happenstance or for research purposes.  I want to post videos because  I am appreciative of what they provide, which is a good idea of what these animals are like in real life.

Are you paying attention at moment 0:50?  A red blur swims by.  I will address this red blur on Thursday, so keep it in mind!

The spiny softshell likes to munch particularly on crayfish and molluscs (2).  Females sexually mature at around 12 years of age, and eggs are laid during June and July in sand or gravel nesting areas.  Other necessities include shallow muddy or sandy areas to bury in, deep pools for hibernation in the winter, and basking areas (2).  Females can grow up to a length of half a meter and weigh 12 kg, males tend to be a tad smaller.  Baby spiny softshells are roughly the size of a toonie (2).  The distribution of these turtles in Ontario can be seen below:

Spiny softshell turtles were last assessed as Threatened in May 2002 by both the Species at Risk Act (SARA) and the Committee on the Status of Endangered Wildlife in Canada (COSEWIC), they have been considered as such since 1991 (2).  In terms of conservation status lingo, “Threatened” is the status below “Endangered”.  According to COSEWIC, the definition of “Threatened” is as follows: “A wildlife species that is likely to become endangered if nothing is done to reverse the factors leading to its extirpation or extinction”.  In Ontario, these turtles are “specially protected” species under Ontario’s Fish and Wildlife Conservation Act.  This means that they are protected from being hunted, trapped, held in captivity, or traded without a license (2).  Unfortunately, this has not saved the spiny softshell from one of the number one contributors to its decline: habitat loss (3).

Habitat loss and fragmentation:

Traditionally, habitat loss has been blamed as the number one cause for population decline in the spiny softshell turtle.  These days, habitat degradation and direct human contact is becoming an increasing cause for concern (3).  However, I will address issues of habitat degradation on Thursday.  Now you may be drawn to ask, “What’s the difference between habitat loss, fragmentation, and degradation?”  Well, habitat loss is the total disappearance of areas for animals to live, whereas habitat degradation is the decrease in quality of the areas that are left.  Habitat fragmentation occurs when large habitable areas have been divided up into smaller areas.  For the purposes of this chat, we will consider human development (such as roads and urban planning) as the main obstruction between these subdivided areas.

I hope you can understand the metaphor of the green and dead leaves. It’s also important to remember that these habitat issues aren’t mutually exclusive, and often appear concurrently.

I have learned from conservation biology that habitat loss and issues regarding habitat quality are generally considered as the leading cause for wildlife decline.  As the world’s population increases and more countries become industrialized, it can only be expected that there will be an increased demand for land and resources.  Sadly, Ontario’s turtles have fallen victim to this dilemma, as indicated by COSEWIC reports (3)(4)(5)(6)(7).  Habitat loss and fragmentation have been implicated as an underlying factor for the decline in all five of my focal species.  Prime wetland habitat is destroyed for urban and shoreline development (3)(4)(6)(7).  The effects of habitat loss should be clear.  If there are less places to live and less resources available, there will be a decline in the animals that live in these places as well.  As stated previously, this is not an isolated problem (8)(9)(10)(11).

In terms of fragmentation, even simple roads built for human traffic have been found to cause high mortality rates in turtles (4)(5)(12)(13).  Perhaps what is even more interesting is the discovery that female turtles are more prominent in road mortality statistics due to their nesting behaviours (they like to nest in the gravel and sandy road side) (14)(15).  This really hurts reproductive output (i.e. number of babies) since turtles don’t give birth as often or as quickly as other animals.  Turtles tend to be long lived species, so they take many years to sexually mature and produce offspring.

I initially thought this mortality may have been solely due to turtles crossing the road too slowly, but then my wonderful classmate provided me with some useful insight that he gained through his field experience.  Rather than actually crossing the road (which I’m sure is problematic in and of itself), turtles apparently like to sit in the middle of the road because it’s warmer (the black cement absorbs heat from the sun).

Aside from road mortality, the issue with habitat fragmentation is that it severely hinders the ability of populations to deal with disturbances.  They are confined to what small territories they have with no way out.  Imagine your house being on fire and not being able to run outside – a scary thought.  In addition, adaptability is low since they are mating within a very small population.  In other words, the same tools are being passed around over and over, despite the fact that these tools may not be right for the job.  Perhaps as evidence for this fact, studies have shown that artificial corridors (think of them as bridges) can improve turtle survival under the stress of short-term disturbances since they provide a means for escape (16).

What can I do?

  • Unfortunately, there is not much that regular people can do to stop development.  I don’t expect you to walk into the wetlands and lobby, however, it may interest you to join some wildlife conservation groups!  I will discuss this in detail on Friday.
  • Please consider that an ecocentric approach must be taken in order to stop habitat destruction.  In order words, there must be concern for the whole environment that turtles lives in, and not just the turtles themselves.
  • Remember to be mindful if you are buying property in a developing area.  It is important to be aware of the environment being sacrificed.
  • If you live in an area with lots of wildlife, refrain from constructing artificial obstructions such as fences, as this would further fragment the habitat
  • In terms of road mortality, stay alert when you are driving through areas that are abundant in wildlife.  Also, studies using drift fences to direct wildlife traffic through extensive highway systems have proved to be effective (17), so take that into consideration if you are ever conversing with your pals (or maybe even people in high places) about conservation issues!  If anything, at least you will sound smart 🙂
  • Tell people about what you’ve learned!

As I stated before, what I really want is to raise awareness and to spread awareness.  If you have learned anything cool from my blog today, please feel free to bring it up for discussion with others!

References

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12 thoughts on “The spiny softshell turtle and the effects of habitat loss and fragmentation

  1. Yes, I did read through all of that.

    Not gonna lie, that turtle got shafted in the turtle gene pool.

    It was surprisingly interesting, I did enjoy reading some of the tidbits about the turtles like how they like to sit on the road; reminds me of your squirrel sunbathing. And I thought your diagrams described the terms about habitat really well. your illustration skills need help though cheryl lol

    Just curious, what are the statuses between threatened and endangered?

  2. according to COSEWIC
    the definition of endangered is:
    “A wildlife species facing imminent extirpation or extinction.”
    while the definition of threatened is:
    “A wildlife species that is likely to become endangered if nothing is done to reverse the factors leading to its extirpation or extinction.”

    generally speaking, i think between them there should be “Vulnerable”, but not by COSEWIC designations.

    if you are interested in knowing more on conservation status in general, feel free to check out the wikipedia entry
    http://en.wikipedia.org/wiki/Conservation_status

    here is more specifically a COSEWIC answer: http://www.cosewic.gc.ca/eng/sct0/assessment_process_e.cfm#tbl2

    do you not like my leaves? i thought that i did a pretty good job. i’m glad that the diagram has aided in your understanding of the subject. after finishing tomorrow’s post i plan to watch BOF

  3. Hello!
    Very Interesting post! Thank you for such interesting resource!
    PS: Sorry for my bad english, I’v just started to learn this language 😉
    See you!
    Your, Raiul Baztepo

  4. What can we do to improve the wetland situation if we own property? Are there plants we should re-plant, trees, etc?

  5. Michelle, that is a great question! The only real suggestion that I have is to prevent development and traffic through the area, or to research some plants native to your property area and maybe replant them. Unfortunately, wetland habitats are very delicate and have intricate natural rhythms that can be difficult to restore if previously destroyed.

  6. Hi-
    Recently I was on a bike ride and I came across two of these guys! I moved the one that was on the path back to the small concrete river where the other one was hanging out. I don’t know that that is the best area for them. Is there a turtle resuce?

  7. hi there! first off, thanks so much for taking the time to read my blog!
    i would like to say that i think that you did the right thing
    you may have noticed the turtle on your ride, but another hiker or biker may not have – it’s good that you got that turtle out of harm’s way
    i also think that you did the right thing by moving it to an area where you saw another spiny softshell, since this would indicate that it’s probably not a problematic location.
    it would be best not to move the little guy too far, since then you could risk taking it out of its “home range”, if you get my drift.
    i am not quite sure what you mean by resuce?

  8. Pingback: The spiny softshell turtle and the effects of habitat loss and … | Pro Earth Forsyth

  9. Hi, i have notices for the last few days that there is a large spiny soft shelled turtle living in a drainage ditch that runs to the pollution plant. It is a pretty shallow ditch. I was wondering how it could have gotten there and if it will survive there?It is right in town. I am from Leamington Ontario and it is the first one of its kind I’ve ever seen here.

  10. haha pancake turtle with the musical nose. This thing gets me every time, too bad their endangered though, that sucks raw eggs man!

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