Month: April 2020

      The world around us is changing. In terms of environmentally, it is changing for the better because of the global pandemic that is occurring. Since there have been lockdowns in most of the major industrial countries, pollution levels and CO2 levels have been down significantly as pollution from cars and major industrial complex processes have decreased. Through this chaos that is going on in the world, we can not lose sight of the things that were being greatly affected by climate change and that will continue to be affected by climate change in the future if we don’t change our habits after the pandemic is over. One of the species that is greatly affected by climate change that could be negatively affected in the future is the Monarch Butterfly.

      One of the most remarkable things about the Monarch Butterfly is their migration. They have a 3,000-mile journey every year from their summer homes in the northern U.S. and Canada to their winter homes in California and Mexico. Sadly, the numbers of these beautiful monarchs are rapidly declining. The 2018 Western Monarch Thanksgiving count found that Monarch’s living in California for the winter declined to only 20,456, a 86% reduction from the previous year (Murawski). The eastern Monarchs in Mexico also declined 15% which adds up to an 80% decline over the past 20 years (Murawski).

      At first look, it might seem like the Monarch Butterfly is less affected by climate change than other animals. These types of butterflies have a high dispersal ability across large geographic ranges. Along with this trait, they have a short generation time and a high reproductive rate meaning that they have a high capacity to adapt to long term environmental changes (“Monarch Butterflies”). Although this can be a good thing, there are many characteristics that the Monarch Butterflies hold that expose them to the effects of climate change.

      Nearly all types of butterflies including Monarch Butterflies, are highly sensitive to a change in weather and climate. Like many other animals, these butterflies depend on environmental cues, like temperature, to do processes such as reproduction, migration, and hibernation (“Monarch Butterflies”). The Monarch’s overwinter habitat is also declining because of climate change, this affects their migration patterns as there are events of long droughts and extreme storms or abnormally hot and cold temperatures (“Monarch Butterflies”). “A lot of environmental threats can pile up on top of each other,” says the University of Wisconsin entomologist and director of the UW-Arboretum, Karen Oberhauser (Murawski). 

      Another negative side effect of climate change on these butterflies is on the milkweed plant. The Monarch is dependent solely on the milkweed plant as a host plant and the milkweed plant is declining throughout the monarch range as climate change increases (“Monarch Butterflies”). Increasing carbon dioxide from the burning of fossil fuels is causing the plant to become too toxic for the monarch caterpillars to eat. More specifically the molecules that are built by milkweed are being altered by the high amount of carbon (Murawski). Ecologist Leslie Decker, a postdoctoral researcher at Stanford University, explains how “milkweed produces toxic steroids called cardenolides and that the monarchs have evolved in a way that allows them to tolerate low levels of this poison, storing it in their bodies as a bitter-tasting deterrent to predators (Murawski).” These cardenolides help the Monarch Butterflies by impeding the growth of a monarch parasite called Ophryocystis elektroscirrha (Murawski). This single-celled parasite can infect newly hatched caterpillars by drilling holes in their gut to replicate. Even if the caterpillars survive this parasite, they are born with misshapen wings and lowered endurance. In a study by Decker, she grew milkweed in a greenhouse with a high level of carbon dioxide and found that the plants produce a different mix of cardenolides, a mix that was significantly less effective against the parasite (Murawski).

      Overall, many animals are being affected in so many different ways as climate change effects continue to increase throughout time. We know that the environment is dependent on each other so even if their animals are not being directly affected by global warming, they are probably being indirectly affected. For the Monarch Butterflies, they are being directly affected in more than one way and if we don’t make changes soon we will eventually see the extinction of this beautiful creature.

 

Sources:

“Monarch Butterflies and Climate Change.” WWF, World Wildlife Fund, www.worldwildlife.org/pages/monarch-butterflies-and-climate-change.

Murawski, Darlyne A., and Medford Taylor. “We’re Losing Monarchs Fast-Here’s Why.” Climate Change, Pesticides Put Monarch Butterflies at Risk of Extinction, 21 Dec. 2018, www.nationalgeographic.com/animals/2018/12/monarch-butterflies-risk-extinction-climate-change/#close.

 

Although it is a time of crisis with the global pandemic of COVID-19 it is important to not forget the problems that can inevitably destroy us in the future. Climate change, an ever-growing risk to the human race and the environment that surrounds us, is still rapidly increasing due to blind ignorance by those in charge. Not only is the human race threatened by global warming and climate change, but the other animals are also very vulnerable to the changes in our environment. One reptile that roams the seas and land, has found itself in great danger in the face of climate change, then green sea turtles.

 

One of the main characteristics of the green sea turtle is the main reason that climate change is threatening the species. The green sea turtle uses both marine and terrestrial habitats during their life cycle which means they are affected by all kinds of changes. On the marine side of things, sea turtles are greatly damaged by changing environments.

 

As global warming rapidly melts ice caps, the global sea level rises. As this level rises the sea turtles nesting beaches are affected. To lay eggs to where the sea turtles’ offspring will hatch, the sea turtles have a strong memory of the beaches and spots where they lay their eggs to hatch every time (Information About). As the sea levels rise these beaches disappear and offspring production is affected.

 

Climate change also affects the nesting beach temperatures for the sea turtles. Since the sea turtles’ are reptiles, they rely on the nest temperature to determine the gender of the hatchling in the nest. Usually, eggs that are in the lower, cooler part of the nest will become males and eggs that are in the upper, warmer part of the nest becoming females (Information About). “With increasing nest temperatures, scientists predict that there will be more female than male hatchlings, creating a significant threat to genetic diversity (Information About). In terms of sea turtle gender-ratio, the beaches at Playa Grande on Costa Rica’s Pacific coast are already producing nests that are 70 percent to 90 percent female, depending on the year (Information About).”

 

Higher ocean temperatures will also negatively impact the food sources for sea turtles. Coral reefs, which are an important food source to the sea turtles, have and will continue to be destroyed due to the “bleaching” effect (Information About). “Since 2005, the Caribbean region has lost 50 percent of its corals, largely because of rising sea temperatures. From 1997 to 1998 alone, mass bleaching is estimated to have caused serious mortality to 16 percent of the world’s coral reefs (Information About).” Another source of food for the sea turtles is prey, and for sea turtles, they have to travel to hunt their prey (Global Warming). Warming ocean temperatures are affecting this migratory species by altering currents and impacting the distribution and abundance of prey species (Global Warming).

 

A lot is affecting the sea turtles species, but the problem of creating mainly female sea turtles is the worst. The problem is rapidly increasing and scientists are trying to find ways to reverse it. One of the solutions that scientists came up with is using shading and relocation techniques. In a study, a mitigation matrix shows that artificial shading and nest relocation can be effective, low-cost, low-technology conservation strategies to mitigate impacts of climate change on sea turtles (Mitigating the …). Marjolijn Christianen, a collaborator from Wageningen University & Research says, “The results of the study surprised us. They show that simple measures can be very effective in preventing a female-only turtle population. The most effective shading material is palm leaves, decreasing temperature by a mean of 0.6 °C. The variation between beaches that are only 1 km apart was an average of 1.9 °C. Relocation between beaches and shading could shift hatchling sex ratio from the current ranges (97-100% female) to 60-90% female — a big difference. (Mitigating the …)”

 

Eventually, the coronavirus pandemic will pass and after a while, we will recover, the economy will be back, and life will return to normal. As normalcy sets back in the push for climate change will have to continue even harder than before. Every year we wait for the planet to change in negative ways and species like the green sea turtle cannot adapt fast enough to survive. The movement for climate change relief must continue if we want to ensure the safety of our planet.

 

“Global Warming & Sea Turtles.” SEE Turtles, www.seeturtles.org/global-warming.

 

“Information About Sea Turtles: Threats from Climate Change.” Sea Turtle Conservancy,

conserveturtles.org/information-sea-turtles-threats-climate-change/.

 

“Mitigating the Effect of Climate Change on Sea Turtles.” ScienceDaily, ScienceDaily, 6 Dec.

2018, www.sciencedaily.com/releases/2018/12/181206115929.htm.