Turtles: Warriors of Biodiversity

By Ananya Malik, Junior Researcher , India Water Foundation

Turtles are reptiles that have been roaming the earth for over 150 million years. Turtles have played and still play an important role in our oceans by maintaining the ecosystem and keeping it in balance. They are very unique vertebrates that have an incorporated shell in their skeleton, made of a fused spine and ribcage which provides it with protection. There are approximately 310 species of turtles living in the world and are divided into 3 major groups- tortoises, freshwater turtles and marine turtles. Sea turtles play an important part in the marine food web. Some of these adaptations can also be found in terrapins and freshwater turtles, while others are specific to marine animals only.They are one of the oldest reptile groups, more ancient than snakes and crocodilians.They are an integral part of interspecies interaction of the marine ecosystem.

Many turtles are scavengers who get their nutrients from eating dead things, in addition to eating living plants and animals. They effectively act like the waterbody’s cleaning crew removing sources of harmful bacteria from the waterbody. This “nutrient” cycling keeps all of the living things in those ecosystems, including us, healthy. Because turtles travel between both aquatic and terrestrial ecosystems they are a major source of energy transfer between the two. Turtles’ diets and unique digestive systems mean that they carry and deliver the seeds, bacteria and nutrients from one habitat to another. They essentially leave the gift of restoration. Turtles help new plants grow and ecosystems thrive.

Reasons why marine turtles are so important –

• Economy- Marine turtles help the economy especially in developing countries through tourism. Marine turtle tourism brings about 3 times more money than selling turtle products, according to an economic study by the WWF.
• Climate change mitigation- another important aspect of sea turtles is that they can help prevent some impacts of Climate Change in coastal communities. Having strong and healthy dune systems and coral reefs will prevent coastal areas to get flooded due to sea level rise and due to an increase of extreme weather events like hurricanes
• Ecology- Sea turtles are very important for different ecosystems and many other species depend on them.
• Control prey- some turtles like the leatherbacks help to control the amount of jellyfish in the ocean while other species help reefs by consuming sponges that would otherwise compete for space.
• Turtle nesting sites help beaches- the nutrients that is left behind from the un-hatched or the hatchlings that don’t survive provide an important source of nutrients for the costal vegetation.
• Hatchlings as a food source- many of the hatchlings provide an important food source for the coastal animals.
• Tourism- Turtles help to increase the economy of local people through tourism.
• Green turtles help to maintain the sea grass levels and making sure that sea grass beds are healthy.

The continued decline of sea turtle populations will have serious economic consequences, particularly for coastal communities in developing countries, said Dr Susan Lieberman, Director WWF’s global Species Programme.Today 6 out of the 7 species of sea turtles are threatened with extinction. With poaching being the most blamed there are many other anthropogenic threats that are the main cause for their decline in population –

• Fisheries: Sea turtles virtually everywhere are affected by fisheries, especially longlines, gill nets, and trawls. The most severe of these impacts are death after entanglement, habitat destruction and food web changes.
• Direct Take: Sea turtles and their eggs are killed by people throughout the world for food, and for products including oil, leather and shell.
• Coastal Development: Sea turtle habitats are degraded and destroyed by coastal development. This includes both shoreline and seafloor alterations, such as nesting beach degradation, seafloor dredging, vessel traffic, construction, and alteration of vegetation.
• Pollution: Plastics, discarded fishing gear, petroleum by-products, and other debris harm and kill sea turtles through ingestion and entanglement. Light pollution disrupts nesting behaviour and causes hatchling death by leading them away from the sea. Chemical pollutants can weaken sea turtles’ immune systems, making them susceptible to disease.
• Climate Change: Climate change will increase the frequency of extreme weather events, result in loss of nesting beaches, and cause other alterations to critical sea turtle habitats and basic oceanographic processes. It may impact natural sex ratios of hatchlings and increase the likelihood of disease outbreaks for sea turtles.

Here is how we can contribute to save turtles bysupport conservation of sea turtles-

• Reduce marine debris that may entangle or be accidentally eaten by sea turtles.
• Participate in coastal clean-ups and reduce plastic use to keep our beaches and ocean clean. Trash in the ocean can harm sea turtles and other creatures that live there.
• Carry reusable water bottles and shopping bags. Refrain from releasing balloons, they’ll likely end up in the ocean where sea turtles can mistake them for prey and consume them.
• Keep nesting beaches dark and safe for sea turtles. Turn off, shield, or redirect lights visible from the beach. Lights disorient hatchling sea turtles and discourage nesting females from coming onto the beach to lay their eggs.
• Do not disturb nesting turtles, nests, or hatchlings.
• Don’t buy souvenirs or other items made from critically endangered hawksbill shell.

Links for more information:

Websites:

• https://www.worldwildlife.org/species/sea-turtle
• https://www.usgs.gov/centers/sbsc/science/turtle-ecology?qt-science_center_objects=0#qt-science_center_objects
• https://www.projectbiodiversity.org/sea-turtles
• https://www.seeturtles.org/why-are-sea-turtles-important
• https://oliveridleyproject.org/ufaqs/why-are-sea-turtles-important-to-the-environment
• https://www.conserveturtles.org/information-about-sea-turtles-why-care/
• https://www.turtleguardians.com/2020/01/turtles-our-heroes-super-power-agents-of-the-earths-biodiversity/

Research articles:

• Aguirre, A. Alonso, and Peter L. Lutz. “Marine turtles as sentinels of ecosystem health: is fibropapillomatosis an indicator?.” EcoHealth1, no. 3 (2004): 275-283.
• Boyer, Don R. “Ecology of the basking habit in turtles.” Ecology46, no. 1-2 (1965): 99-118.
• Murthy, T. S. N. “Turtles: Their natural history, economic importance and conservation.” Published: February, 1982(1981): 57.
• Lovich, Jeffrey E., Joshua R. Ennen, Mickey Agha, and J. Whitfield Gibbons. “Where have all the turtles gone, and why does it matter?.” BioScience68, no. 10 (2018): 771-781.
• Stanford, Craig B., John B. Iverson, Anders GJ Rhodin, Peter Paul van Dijk, Russell A. Mittermeier, Gerald Kuchling, Kristin H. Berry et al. “Turtles and tortoises are in trouble.” Current Biology30, no. 12 (2020): R721-R735.
• Santori, Claudia,. “Scavenging by threatened turtles regulates freshwater ecosystem health during fish kills.” Scientific reports10, no. 1 (2020): 1-7.