Climate Change: Vulnerability Based on Ecological Habitat

Climate change is today’s political hot button. But make no mistake, the threat to our species is real due to rapid temperature changes. It is estimated that by 2050, even with minimal climate-warming changes, 18% of terrestrial species will be committed to extinction due to global temperature change (Thomas et al., 2004). As I have discussed in my previous blog post, species which have short life history characteristics (quick to sexual maturity, high fecundity, smaller body size) are species which are able to respond and adapt the most quickly to climate change (Perry, Low, Ellis, & Reynolds, 2005). This means that most bony fishes are able to respond relatively quickly to changes in climate.

Coral Reef Fishes
Coral Reef Fishes [Digital Image] Retrieved from https://cdn.pixabay.com/photo/2015/09/23/16/49/coral-reef-954057_960_720.jpg

Elasmobranchs, however, do not exhibit the same life history characteristics as bony reef fishes, which leaves them more vulnerable to climate change affects (Perry, et al., 2005). Climate change effects can be exerted on sharks and rays in two distinct ways: as Direct Effects and Indirect Effects (Chin, Kyne, Walker, & McAuley, 2010). Direct Effects influence the physiochemical environment a shark or ray inhabits, including temperature changes, freshwater input from streams or rainfall, and ocean acidification (Chin, et al., 2010)

Distant Rain
Inaglory, B. (Photographer). (2006). Distant Rain [Digital Image] Retrieved from https://upload.wikimedia.org/wikipedia/commons/e/e2/Rain_ot_ocean_beach.jpg

Indirect Effects influence the geophysical, ecological, or biological processes that occur within a habitat. These can influence the health of the environment. Indirect Effects can include factors under Direct Effects, such as temperature changes or freshwater input, if they influence the processes within the environment (Chin, et al., 2010). Indirect Effects also include air temperature, sea level rise, severe weather events, ultraviolet and light radiation, and ocean circulation (Chin, et al., 2010).

Labrador Current
Schwen, D. (Photographer). (2008, April 6). Labrador Current [Digital Image] Retrieved from https://upload.wikimedia.org/wikipedia/commons/e/e2/Labrador_Current.jpg

Direct and Indirect effects can have profound impacts on elasmobranchs. It has been suggested that some species, like round stingrays (Urobatis halleri) and leopard sharks (Triakis semifasciata), use behavioral thermoregulation, aggregating in warmer water in order to optimize metabolic and physiological processes, including reproduction (Hight & Lowe, 2007; Hoisington & Lowe, 2005). If thermal conditions are not able to be met for these species due to changing climate, they are not able to meet their physiological requirements necessary for reproduction and other processes. This can be detrimental for their populations.

Urobatis halleri
Ilyes, L. (Photographer). (2007, November 19). Urobatis halleri [Digital Image] Retrieved from https://upload.wikimedia.org/wikipedia/commons/e/e7/Urobatis_halleri.jpg

In 2010, a study of elasmobranchs on the Great Barrier Reef in Australia concluded that the most significant factors due to climate change to affect all marine ecological groups were temperature, freshwater input, and ocean circulation (Chin, et al., 2010). The study divided marine habitats in six ecological groups:

  • Freshwater/Estuarine- Rivers & streams, intertidal zones of estuaries and bays, mangroves and salt marshes, intertidal grasses, foreshores and mudflats
  • Coastal/Inshore- Extending from subtidal to mid-shelf platform or ribbon reefs
  • Reef- On or immediately adjacent to mid-shelf and outer shelf coral reefs
  • Shelf- Deeper water and seabeds between the mid-self and outer reefs, extending to the continental slope edge. Includes waters from surface to 200m
  • Pelagic- Open ocean waters extending from the edge of the outer reefs and beyond into the Coral Sea
  • Bathyal- Benthic habitats of the continental slope and beyond, extending down to 2000m depth
Analysing the vulnerability of sharks and rays
Chin, A., Kyne, P. M., Walker, T. I., & McAuley, R. B. (2010). An integrated risk assessment for climate change: Analysing the vulnerability of sharks and rays on Australia’s Great Barrier Reef. Global Change Biology, 16(7), 1936–1953.

Species within the freshwater/estuarine habitats were considered to be the most vulnerable to the effects of climate change. These species experience extremes in water quality and rising temperatures more than the other ecological habitats, which could negatively impact habitats such as salt marshes, mangroves, and sea grasses   (Chin, et al., 2010).  These habitats are also likely to be impacted by increased physical disturbance from severe storms and changes in salinity due to alteration in rainfall and changing sea levels (Chin, et al., 2010).

Salt Marsh
Hartmann, T. (Photographer). (2012, April 22). Salt Marsh [Digital Image] Retrieved from https://upload.wikimedia.org/wikipedia/commons/9/97/Salt_marsh_Georgia_US.jpg

Reef species were considered to have moderate to high vulnerability to climate change factors, including increased UV and light radiation, increased storm activity, ocean acidification,and rising temperatures (Chin, et al., 2010). Species with the lowest vulnerability to climate change factors were species found in deeper or more open water environments such as coastal, pelagic, shelf, and bathyal habitats (Chin, et al., 2010). These species have relatively few factors which alter their physiochemical environment or processes, however temperature remains their greatest threat (Chin, et al., 2010).

Oceanic White Top Shark
Vasenin, A. (Photographer) (2016, November 6). Oceanic White Top Shark [Digial Image] Retrieved from https://upload.wikimedia.org/wikipedia/commons/4/4f/Oceanic_whitetip_shark_at_Elphinstone_Reef.jpg

Species which live in pelagic or shelf habitats may also be affected by changing ocean currents. It has been suggested that changes in ocean currents can alter patterns of upwellings. These upwellings bring nutrient rich waters from the deep, which in turn drive productivity at the surface and ultimately leads to prey availability for meso- and apex predators like sharks and rays (Chin, et al., 2010). In recent years, changes in the El Niño and La Niño cycles in the Pacific Ocean have led to significant biological productivity and prey availability alterations (Kingsford & Welch, 2007).

Whale Shark Eating Plankton
Jaontiveros (Photographer). (2010, August 27). Whale Shark Eating Plankton [Digital Image] Retrieves from https://upload.wikimedia.org/wikipedia/commons/3/3a/Whale_shark_eating_plankton.JPG

You have the ability to make change. By making small changes in your daily routine, such as reducing emissions, saving energy, and recycling, you are supporting climate change initiatives.

Climate Change
Sustainability for All [Digital Image] (n.d.) retrieved from http://www.activesustainability.com/climate-change/6-actions-to-fight-climate-change/

But it is going to take social and political changes to bring about global changes needed to save species from extinction. The best thing you can do at any time is call your Congress man or woman and tell them that you care about climate change initiatives and keeping sharks in our oceans!

Next time we will continue our exploration of climate change effects on elasmobranchs by taking a closer look at how rising temperatures can impact seasonal migration patterns.

As always I welcome your comments and feedback! Thanks for joining me!

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Featured Image Source

Geralt (Creator). Earth. {Digital Image}. Retrieve from https://pixabay.com/p-216834/?no_redirect

Literature Cited

Chin, A., Kyne, P. M., Walker, T. I., & McAuley, R. B. (2010). An integrated risk assessment for climate change: Analysing the vulnerability of sharks and rays on Australia’s Great Barrier Reef. Global Change Biology, 16(7), 1936–1953.

Hight, B. V., & Lowe, C. G. (2007). Elevated body temperatures of adult female leopard sharks, Triakis semifasciata, while aggregating in shallow nearshore embayments: Evidence for behavioral thermoregulation? Journal of Experimental Marine Biology and Ecology, 352(1), 114–128.

Hoisington IV, G., & Lowe, C. G. (2005). Abundance and distribution of the round stingray, Urobatis halleri, near a heated effluent outfall. Marine Environmental Research, 60(4), 437–453.

Kingsford, M. J., & Welch, D. J. (2007). Vulnerability of pelagic systems of the Great Barrier Reef to climate change. Climate Change and the Great Barrier Reef: A Vulnerability Assessment, 555–592.

Perry, A. L., Low, P. J., Ellis, J. R., & Reynolds, J. D. (2005). Climate change and distribution shifts in marine fishes. Science, 308(5730), 1912–1915.

Thomas, C. D., Cameron, A., Green, R. E., Bakkenes, M., Beaumont, L. J., Collingham, Y. C., … Williams, S. E. (2004). Extinction risk from climate change. Nature, 427(6970), 145–8.

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8 thoughts on “Climate Change: Vulnerability Based on Ecological Habitat

Add yours

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