How Are Turtle Affected by Climate Change
There are many species falling prey to planetary challenges, but have you ever pondered over: How are turtles affected by climate change?
Climate change impacts turtles in profound ways. Notably, it interferes with their nesting sites, food availability, and alters the sex ratio of hatchlings due to temperature-dependent sex determination, leading to potential population imbalances.
Dive deeper with me into this topic, as we explore the startling effects of climate change on the resilient, yet vulnerable, marine and terrestrial turtles.
Unraveling the Life of Turtles
Turtles are an essential part of our planet’s diverse ecosystems. These reptiles, often characterized by a bony or cartilaginous shell, are a part of both terrestrial and aquatic habitats worldwide. From the smallest swamp to the vast ocean, turtles play a significant role in maintaining the health and balance of these ecosystems.
Turtles are recognized as both predators and scavengers. They contribute to nutrient cycling by feeding on a variety of organisms, including insects, fish, and plants. Some turtles also consume dead animal and plant material, helping to clean up the ecosystem by removing decaying matter. They also serve as prey to a range of predators, thereby aiding in maintaining the food chain.
Besides their role in food chains, turtles also play a significant role in shaping the physical landscape of their habitats. For instance, during their nesting process, they alter sand dunes’ structure, leading to a change in vegetation, which can influence the biodiversity in those areas over time.
Also, in the case of aquatic turtles, these creatures play the role of ecosystem engineers by altering aquatic habitats by their activities that usually end up changing the water’s distribution and flow. This typically affects other aquatic organisms and their habitats positively.
Transitioning from their critical roles within the ecosystem, it’s worth noting the astounding diversity in the species of turtles we have globally. There exist around 360 known species of turtles, each varying remarkably in size, lifestyle, habitat preference, and diet. For instance, the leatherback sea turtle, the largest sea turtle species, can reach up to 7 feet in length and weigh over 2,000 pounds, while the speckled cape tortoise, one of the smallest turtle species, merely maxes out at around 4 inches in length.
These species of turtles are spread globally with each geographical region hosting different specific species. Turtles inhabit all continents except Antarctica. They dwell in a variety of habitats including deserts, wetlands, forests, and even the open ocean. Some species are highly adaptable and can sustain in different environments while others are specialized and inhabit only very specific niches. Each unique turtle species holds immense ecological value and contributes to the overall biodiversity of our planet.
Understanding Climate Change
Climate change, a topic of global concern, often raises concerns for everyone. It affects every aspect of life on earth in ways we are still grappling to understand in full. To integrate this concept better, let’s start by understanding the fundamental facts about this global phenomenon and what it means for the animal kingdom – in this case, for turtles especially.
The Indisputable Facts about Global Warming
Scientific evidence for global warming is vast and undisputable. According to the National Aeronautics and Space Administration (NASA), the earth’s average surface temperature has risen by about 1.62 degrees Fahrenheit (0.9 degrees Celsius) since the late 19th century, predominantly due to the increased levels of carbon dioxide and other human-made emissions. This warming is responsible for the dramatic alteration in global climate patterns.
Commonly referred to as global warming, this increase in earth’s average temperature leads to the melting of polar ice caps and the rise in sea levels. Data from NASA’s Gravity Recovery and Climate Experiment show Greenland losing an average of 281 billion tons of ice per year between 1993 and 2016, while Antarctica lost about 119 billion tons during the same time frame.
How Human Activities Contribute to Climate Change
An essential aspect of climate change is human activity. As per the Intergovernmental Panel on Climate Change (IPCC), more than half of the temperature increase since 1950 can be attributed to human activities, particularly those involving the burning of fossil fuels and deforestation.
Mass industrialization and excessive use of fossil fuels lead to an increase in greenhouse gases. These gases trap heat from the sun within our atmosphere, resulting in a rise in global temperatures. This effect, known as the greenhouse effect, is the primary driver of the current global warming we are experiencing.
Deforestation, another crucial contributor, emboldens the harmful impacts of climate change. By removing trees – which absorb CO2, one of the main greenhouse gases – we are increasing the amount of CO2 in our atmosphere and tipping the natural balance of our ecosystem.
While these actions may seem distant and unrelated to the life of a turtle, the consequences are far-reaching and interconnected. The impact on these gentle creatures is direct and profound, something we will delve into in the subsequent sections.
Connecting the Dots: Turtles and Climate Change
Turtles are remarkable creatures, and yet, they are one of the most affected by climate change. Let’s take a deeper look at how turtles and climate change intersect, and why these effects are a concern for them.
Temperature-Dependent Sex Determination
Unlike many species, the sex of a turtle is not necessarily determined at the time of fertilization. Instead, it is influenced by the temperature at which the eggs are incubated. This is known as temperature-dependent sex determination. When the eggs are incubated at warmer temperatures, more female turtles are produced; cooler temperatures result in more males.
With rising global temperatures due to climate change, there is a grave concern that populations could become heavily female-biased, threatening genetic diversity and long-term survival of certain turtle species.
Rising Sea Levels: A Threat to Nesting Sites
Sea-level rise, another consequence of climate change, also poses a threat to turtle populations. Many sea turtle species depend on sandy beaches for their nesting sites. As sea levels rise, many of these beaches are at risk of disappearing. This could force turtles to nest in less-than-ideal locations, threatening the survival of hatchlings.
How Beach Erosion Affects Turtle Nesting Success
In addition to inundation, rising sea levels can also lead to increased coastal erosion. This not only reduces the available nesting habitat but can also expose and destroy turtle nests buried within the sand. According to a 2013 study, beach erosion could reduce hatching success by up to 50% in certain populations.
Ocean Acidification: A Double-Edged Sword
Ocean acidification is another alarming consequence of climate change. As the amount of CO2 in the atmosphere increases, more is absorbed by our oceans, leading them to become more acidic. This altered ocean chemistry can harm not only coral reefs, which are crucial habitats for many species of sea turtles, but can also affect the turtles themselves.
Changes in ocean chemistry can deter growth and increase the vulnerability of sea turtles, making it harder for them to survive. Similarly, ocean acidification also affects the abundance and quality of the turtles’ main food sources, further endangering their survival.
Zooming In: Case Studies of Turtles Affected by Climate Change
The challenges faced by the world’s largest sea turtle, the Leatherback Turtles, are indicative of the broader impacts of climate change on turtles. The Leatherbacks have been around for more than 100 million years; however, this ancient species is struggling to adapt to the rapidly changing climate.
One of the most significant impacts of climate change on these marine giants is the alteration in their nesting sites. With sea levels rising, the beaches where the Leatherbacks lay their eggs are shrinking, minimizing the areas where they can nest. Additionally, the increase in temperature causes a gender shift in these turtles. The sex in many turtle species, including Leatherbacks, is determined by the temperature of the incubating egg – warmer temperatures produce more females, while cooler ones yield more males. Climate change-induced temperature spikes could lead to skewing of sex ratios and eventually, population decline.
In 2018, a study published in the journal Nature Climate Change revealed that more than 96% of the hatchlings from northern Great Barrier Reef’s Green Turtles were females; this is twice the number of female hatchlings as compared to just two decades ago. This displays the alarming impact of climate change on the population dynamics of these turtles.
The Green Turtles, so-named for the color of their cartilage and fat, are also vulnerable to rising sea temperatures as they change their feeding behavior and migration patterns. These shifts can heavily affect their health and reproductive capabilities. Additionally, ocean acidification, another symptom of climate change, affects the growth of seagrass, a primary food source for Green Turtles. Their nutritional health, therefore, is directly dependent on the health of the seagrass meadows.
Climate change also affects the Green Turtles in a more cruel way. They are ectothermic, which means their body temperature is determined by their surroundings. When turtles experience ‘cold-stunning’ – a hypothermic reaction to cold water temperatures – they can become lethargic, stop eating, or even die if the temperature does not rise quickly enough.
In conclusion, whether it is the Leatherback Turtles or the Green Turtles, they are on the front line of the threats posed by climate change. These challenges compel us to mitigate our impact on the environment and work towards a sustainable future to ensure the survival of such essential species.
Scientific Forecasts: A Bumpy Road Ahead for Turtles
Climate change presents a grave challenge to the survival of many species, and turtles are no exception. Many of the documented and projected impacts are alarming, especially given the slow pace at which turtles can adapt to changes in their environment.
Modeling Future Impacts of Climate Change on Turtle Populations
Modeling potential future impacts and predicting their consequences can provide valuable insights to shape conservation efforts. A 2018 study conducted by scientists at the University of Exeter discovered that for some turtle populations, more than 90% of the hatchlings are female, all because of changing climate conditions. Turtles have temperature-dependent sex determination, where warm incubation temperatures yield more females, while cooler temperatures yield more males. As global temperatures rise, turtle populations might end up having far more females than males, that may cause instability in their diversity and reproduction.
Predicting the Potential Extinction of Certain Turtle Species
The risk of extinction is true and troubling. For instance, the painted turtles in North America are at risk. According to a report published in the journal American Naturalist, It was found that if current global warming trends continue, no male painted turtles could be born by 2100. This is due to the rising temperatures leading to huge female biases in the newborns, which could drive the species to extinction.
Moreover, sea level rise, another consequence of climate change, threatens the nesting sites of marine turtles. As stated in a report by the World Wildlife Fund (WWF), almost 90% of the most important beaches for loggerhead turtles will be seriously affected by coastal erosion by 2100. This not only threatens turtles’ nesting habitats, but it also makes the nests absolutely susceptible to flooding. Baby turtles, therefore, could drown even before they have a chance to hatch.
With these forecasts, it’s crucial to acknowledge the inherently turbulent future that lies ahead for turtles, as we continue to grapple with the persisting and extensive impacts of climate change.
What Can We Do: Conservation Efforts to Save Our Turtles
Climate change poses an existential threat to turtles, but several innovative solutions can help protect their nesting sites. One of them is the establishment of “turtle sanctuaries”. These are marked areas where the eggs are relocated to, offering them protection against erosion, inundation and human interference. Their effectiveness is backed by data, for instance, a study carried out in Florida showed a significant increase in hatchling production at relocated nests (321 hatchlings per nest) compared to those left in situ (180 hatchlings per nest).
Another effective solution that has found success involves the some usage of technology. For example, 3D printed decoy turtle eggs equipped with GPS trackers have been used to infiltrate the illegal trade and find out where the eggs are being sold. A successful pilot study carried out in Costa Rica enabled law enforcement to track the routes of poachers and this resulted in a marked decline in egg poaching in the following year.
Policy Changes and How They Help
On a larger scale, policy changes also play a crucial role in turtle conservation. For instance, laws that strictly regulate beachfront lighting can help prevent disorientation of hatchlings that often mistake artificial lights for the natural moonlight they are instinctually drawn to. In Melbourne Beach, Florida, lighting ordinances have resulted in successful nesting for the local loggerhead turtle population. A study published in the Journal of Wildlife Management indicated that the hatchling orientation success rate improved from 35% to more than 85% with these new laws in place.
Furthermore, policies that restrict shoreline armoring (the practice of hardening the shoreline to prevent erosion) also benefit turtle conservation efforts. Shoreline armoring interferes with the turtles’ natural nesting process and policy changes towards this can help prevent the decline of suitable nesting habitats. For example, in South Carolina, after a policy which limited the use of seawalls was implemented, there was a marked increase in leatherback turtle nests.
Individual Actions: Small Steps for Big Impacts
While the previous measures largely rely on authorities and organizations, individuals too can make significant contributions. Simple actions like cleaning up beach litter can protect turtles from injury and prevent the contamination of their habitats. In 2020, the Ocean Conservancy’s International Coastal Cleanup reported that volunteers collected over 20.8 million pounds of trash worldwide, including common items that can harm turtles, such as plastic bags and fishing nets.
Individuals can also support turtle-friendly businesses, such as those that adhere to sustainable fishing methods that minimize bycatch and those that do not use turtle shells or other parts in their products. Such actions can have a direct effect on market demands and can motivate other businesses to adopt turtle-friendly practices. Lastly, support for organizations that are actively involved in turtle conservation can be an impactful step. In 2019, the Sea Turtle Conservancy reported that through their adopt-a-turtle program, they were able to protect more than 1 million turtle hatchlings.
Resources
- https://climate.nasa.gov/news/2879/climate-change-puts-pressure-on-sea-turtles/
- https://ncseagrant.ncsu.edu/hooklinescience/is-climate-change-affecting-baby-sea-turtles/
- https://pubmed.ncbi.nlm.nih.gov/19895975/
