As part of our summer-long blog series, Kirstin Silvera, a member of the CC-RAI team will be discussing climate change and its impact on coral reefs, biodiversity and more from a research placement in Costa Rica. Kirstin is currently a graduate student in the Faculty of Environmental Studies at York University and will begin her Law degree this coming fall. In the final blog of the series, Kirstin outlines the impact climate change could have already dangerous endangered sea turtle species.

A young turtle 'coming home' to the sea - a new and dangerous journey.

Tortuguero, a small village located on the northern Caribbean coast of Costa Rica is the most important nesting beach for green turtles (Chelonia mydas) in the western hemisphere (STC, 2011). The beach is also an important nesting site for leatherback (Dermochelys coriacea), hawksbill (Eretmochelys imbricata) and loggerhead turtles (Caretta caretta). Of these species, greens and loggerheads are listed by the IUCN as endangered, while leatherbacks and hawksbills are listed as critically endangered. This makes Tortuguero a crucial player in the successful nesting of these species, and therefore an important factor for their continued existence.

This summer I was working for an organization around Tortuguero, collecting data on nesting sea turtles. In preparing my final blog for the summer I thought it might be interesting to explore how climate change may impact these already endangered species.

Up to and including the point at which sea turtles reach sexual maturity they face many natural and anthropogenic threats including, human development and subsequent habitat destruction, by-catch threats, pollution, and a range of natural predators(Hawkes, Broderick, Godfrey, and Godley, 2009). Sea turtles are one of the oldest species on the planet and “have evolved with continuous habitat alteration through natural coastal processes such as seasonal erosion, accretion and high-tide flooding. The extensive coastal development seen in the last 30 years on many Caribbean islands, however, has occurred within the time required by some turtle species to reach maturity, and then impacts of rapid habitat modification are only now starting to emerge” (Fish, Cote, Gill, Jones, Renshoff, and Watkinson, 2003).

Other climatic factors that could be affected by climate change, “such as extreme weather events, precipitation, ocean acidification and sea level rise also have potential to affect marine turtle populations” (Hawkes, Broderick, Godfrey, and Godley, 2009). Because of this, as climate change alters sea turtle habitats, impacts from natural and anthropogenic sources could be exacerbated. Of particular importance are 3 key characteristics that make sea turtles vulnerable to climate change impacts.

A diagram that illustrates the feedback loops in which climate change could impact sea turtles in their breeding and nesting phases. The + and – indicate the likely direction of the effect (Diagram from: Hawkes, Broderick, Godfrey, and Godley, 2007).

1. Turtles are loyal to their nesting sites

Beaches are essential habitat for nesting sea turtles (Fish et al, 2003). Recent studies suggest that marine turtles return to the same beaches where they were born to nest –  year after year. As a result it is critically important that these beaches remain intact. Climate change and associated sea level rise has the potential to have serious impacts. As sea levels rise, the natural shoreline becomes more eroded than usual (Fish, Cote, Gill, Jones, Renshoff, and Watkinson, 2003). Due to development associated with tourism on many parts of the Caribbean coast, nesting beaches could be lost. In addition to threats from erosion and development nests are also at risk from inundation, thereby resulting in increased hatchling mortality and an overall decrease in the success of nesting females (Robinson et al, 2005; Fish et al, 2003).

2. Sexual determination is temperature dependent

Temperature dependent sex determination means that for species, such as turtles that lay their eggs in the ground, the sex of the offspring depends on the temperature of the eggs during incubation (Hawkes, Broderick, Godfrey, and Godley, 2007). Even if the temperature of the nest changes as little as 1 degree Celsius, the sex ratios of offspring could be altered. As the climate changes and the temperatures of nesting locations change, sex ratios can become skewed either towards males or females (Hawkes, Broderick, Godfrey, and Godley, 2007; Janzen, 1994). If clutches become female biased, there may not be enough males to fertilize eggs in the future, and if clutches become male biased, populations may not have enough females to continue to reproduce successfully.

3. The range of sea turtles is growing

New hatchlings getting acquainted with their new surroundings.

Like other reptiles, turtles are cold blooded. They rely on their environment to moderate their body temperature. If ocean temperatures warm as a result of climate change, the range for various turtle species may expand. Many turtle species have very large ranges. (Hawkes, Broderick, Godfrey, and Godley, 2009). As the ranges expand, it will becomes increasingly difficult to make sure that they are protected in different locations. Climate change could also disrupt food chains as well as surface currents, all of which could have a profound impact on sea turtle species (Hawkes, Broderick, Godfrey, and Godley, 2009).

Like many species already facing threats from climate change a wide array of potentially detrimental factors are in play. As many species of sea turtle are already critically endangered the risk a changing climate could have is extremely worrying. In order to maintain, sustain and protect this ancient species will necessitate new research and a renewed commitment to the species currently and potentially at risk.

References:

Fish, M.R., Cote, I.M., Gill, J.A., Jones, A.P., Renshoff, S., and Watkinson, A.R. (2005). Predicting the Impact of Sea-Level Rise on Caribbean Sea Turtle Nesting Habitat. Conservation Biology, 19, 482-491.

Hawkes, L.A., Broderick, A.C., Godfrey, M.H. and Godley, B.J. (2009). Climate change and marine turtles. Endangered Species Research, 7, 137-154.

Hawkes, L.A., Broderick, A.C., Godfrey, M.H. and Godley, B.J. (2007). Investigating the potential impacts of climate change on a marine turtle population. Global Change Biology, 12, 923-932.

Hays, G.C., Broderick, A.C., Glen, F. and Godley, B.J. (2003). Climate change and sea turtles: a 150-year reconstruction of incubation temperatures at a major marine turtle rookery. Global Change Biology, 9, 642-646.

Janzen, F.J. (1994). Climate change and temperature-dependent sex determination in reptiles. Proc. Natl. Acad. Sci. USA, 91, 7487-7490.

Robinson, R.A., Learmonth, J.A., Hutson, A.M., Macleod, C.D., Sparks, T.H., Leech, D.L., Pierce, G.J., Rehfisch, M.M., and Crick, H.Q.P. (2005). Climate Change and Migratory Species. A Report for Defra Research Contract CR0302.

Sea Turtle Conservancy (STC). (2011). Tortuguero National Park, Costa Rica. Retrieved from: http://www.conserveturtles.org/volunteer-research-programs.php?page=tortnp.

Weishampel, J.F., Bagley, D.A., and Ehrhart, L.M. (n.d.). Earlier Nesting of Loggerhead Sea Turtles Following Sea Surface Warming. Department of Biology, University of Central Florida.

Witt, M.J., Hawkes, L.A., Godfrey, M.H., Godley, B.J., and Broderick, A.C. (2010). Predicting the impacts of climate change on a globally distributed species: the case of the loggerhead turtle. The Journal of Experimental Biology, 213, 901-911.

Costa Rica's Cloud Forests (Flickr gwegner.de | Creative Commons)

As part of our summer-long blog series, Kirstin Silvera, a member of the CC-RAI team will be discussing climate change and its impact on coral reefs, biodiversity and more from a research placement in Costa Rica. Kirstin is currently a graduate student in the Faculty of Environmental Studies at York University and will begin her Law degree this coming fall. In the second of her blog series, Kirstin outlines the impact of climate change Costa Rica’s cloud forests.

Costa Rica is home to a rich amount of species diversity contained in each of its many ecosystems. It is one of the top 20 most biodiverse countries in the world, due in part to its varied geography which provides essential microclimates for many of its endemic species (INBio, 2012). Costa Rica’s landscape spans both the Caribbean and Pacific coastline that begin at sea level and leads into the central mountain range, which rises to over 3000 metres above sea level (University of Massachusetts Amherst, 2008). These changes in elevation cause differences in temperature and moisture which allow for a wide variety of distinct ecosystems and endemic species to exist (University of Massachusetts Amherst, 2008). Of particular importance are Costa Rica’s montane cloud forests that support many endemic species.

Costa Rica - Cloud Forests of the Montane (Flickr davidgordillo | Creative Commons)

The Importance of Costa Rican Cloud Forests

Cloud forests rely on regular cloud immersion in order to maintain their unique ecosystem (Foster, 2001). Because of its mountainous landscape, Costa Rica is home to several cloud rainforests (INBio, 2012). These cloud forests exist above 1000 metres because of continuous horizontal circulation of precipitation, and are highly dependent on the height at which the clouds form for their existence (University of Massachusetts Amherst, 2008). Recent climate models are however predicting that with climate change, Costa Rican cloud forests could be negatively affected as they become warmer and drier (University of Massachusetts Amherst, 2008).  If the predicted rise in temperature happens, species ranges in temperate zones are expected to shift upwards of 600 metres in elevation (University of Connecticut, 2008). With many species in these regions of Costa Rica having very limited altitudinal ranges, a 600 metre shift in elevation would put them in an ecosystem that they had not previously inhabited. These changes would consequently force other species to move out of their natural habitats.

Tropical regions may not be the first concern when one thinks about the effects of climate change, however, studies have shown a rise of approximately 0.75 degrees Celsius in the tropics since 1975. Climate change models are also predicting a further rise of 3 degrees Celsius in the next 100 years in Central and South America (University of Connecticut, 2008). “According to Karmalkar, as temperatures rise, various ecosystems will try to migrate to where they are comfortable, moving in an upslope direction in this case. As they migrate, plants and animals will disturb other species, and eventually run out of space as they reach the top of the mountains. The result may be a loss of many species that can’t survive the new conditions.” (University of Massachusetts Amherst, 2008). Preliminary studies have shown that the cloud bank around Monteverde Cloud Forest in Costa Rica is rising due to climate change (Pounds, Fodgen and Campbell, 1999).

Costa Rica - Endemic species rely of the cloud forests for survival (Flickr Erik B | Creative Commons|

Some researchers have gone as far as to say that “endemic species may provide early warning signals for climate change as an extinction driver because they will be the first to move outside their modeled climatic envelope” (Schwartz et al., 2006). Climate change caused changes to bird and lizard populations in Monteverde in the past which rebounded to cause extinction of other species (Pounds, Fogden and Campbell, 1999), making understanding and mitigating climate change all the more important for sensitive ecosystems such as the cloud forests of Costa Rica.

Other interesting resources:

La Selva Biological Station: La Selva Holds Two Workshops Addressing Climate Change

Área de Conservación Guanacaste (iACG): Climate Change and Biodiversity Workshop

References

September 27^th was Earth Overshoot Day, which marked the day that humans had used all the resources the earth could replenish for 2011. In other words, we utilized a year of resources in just nine months. If everyone in the world lived like North Americans, it would take approximately five planet earths or five times the resources that the earth can provide to sustain the global population.

In a video, the Global Footprint Network explains the overshoot concept and how the process of consuming more than what is naturally available to humans has developed over time.

Ecological overshoot and footprint are terms that are often used in a complementary manner. Ecological footprint is an accounting tool that represents how much we use compared to how much we have. Overshoot denotes the amount by which we are over how much we have versus how much we utilize.

Ecological footprint can be used for a wide variety of conservation measures, one of which is helping to protect valuable biodiversity and ecosystem services provided by our natural landscape.  This tool allows us to understand which sectors are placing the most pressure on our environment and significantly contributing to biodiversity loss. This knowledge enables us to take action to address the concern.

Similarly, this concept can illustrate the impacts of pollution and greenhouse gas emissions in the atmosphere and the need for different sources to reduce their contributions.

The idea of using footprints to account for how much pressure humans put on the earth can help us become more conscious about what we use, how much we consume, and where our products originate. Inherently, it encourages us to be more sustainable.

Yasuni National Park, Ecuador

Hundreds of millions of barrels of oil are believed to exist underground  Yasuni National Park, a UNESCO world biosphere reserve in eastern Ecuador. As one can imagine, there has been some interest in extracting these reserves. According to national and international scientists, this park is home to the greatest biodiversity on earth. The region is also the home to the Huaorani, Tagaeri and Taromenane indigenous peoples, who live sustainably within the confines of this park. Given the incredible value of the commodity that lies beneath the forests, there is significant economic pressure to uproot people, animals and earth. That is unless the Ecuadorian government can raise enough money to justify leaving the oil in the ground. The Ecuadorian government is hoping to be compensated for 50% of the income it will forgo by leaving the oil in the ground. This amounts to US$ 3.6 billion over a 13 year period, which is no small sum. However, the value of reserve, the ecosystem services it provides, and the greenhouse gases it keeps out of the atmosphere are equally valuable.

Spider monkeys and fungus flourish in Yasuni National Park - a UNESCO biosphere reserve

Following the disaster in the Gulf of Mexico in 2010 (among others), the costs of exploiting oil and the impact that a major incident could have on people and their livelihoods, the oceans and the species that share them is increasingly and viscerally understood. The reality remains that the world relies of fossil fuels – and our appetite for them continues to increase. While we continue to pursue the expansion of renewable energy, the global economy is still very much tied to oil. While as a society we try to decrease our reliance on this form of energy and the impact it has on our climate, we can take bold, innovative and creative steps to protecting the environment. An investment in the Yasuni ITT Trust Fund represents an opportunity for individuals around the world to stake a claim for conservation. If it is pursued, oil exploration is expected to create several social and environmental concerns, including the contamination of land, destruction of forests and extinction of local cultures, or at the very least, the social fabric of the area. By keeping the oil in the ground, Ecuador stands to protect its indigenous peoples, conserve its valuable biodiversity and limit its future contributions to greenhouse gas emissions. At the same time, the world benefits from the preservation of biodiversity and the substantial amount of carbon that will not be released into the atmosphere.

Yasuni National Park is one of the most biologically diverse regions on the planet. A untold species - and homo sapiens as well

In 2007, Rafael Correa, President of Ecuador, agreed with a civil society proposal that the oil of Yasuni should remain underground. Since then, efforts have been underway to find a way to fund the initiative. However, time is running out. Despite some major donations, Ecuador needs to raise $100 million dollars by December 31, 2011. Approximately $60 million dollars is still outstanding. Working with the United Nation Development Program’s Multi Partner Trust Fund Office, the Equadorian government hopes to raise millions to protect Yasuni with the help of other governments, NGOs, and the global community.

While the debate rages over the development of newly discovered oil reserves in the Arctic, large companies like Shell are dealing with oil spills in the North Sea and lawsuits in Nigeria. The economic costs associated with the Deepwater Horizon spill are estimated well into the billions. The compensation fund BP had to establish has swelled to $20 billion dollars.

Admittedly, a lot of money may lie underneath the Yasuni reserve. However, an equally significant amount stands to be saved by keeping it there. It’s a carbon piggybank with an incredible value – keeping all that CO2 underground seems like a steal for $3.2 billion over 13 years. With the direct and indirect costs of climate change impacting nations and peoples around the world, protecting Yasuni seems like a sound economic investment if you value the atmosphere.

I was grateful to attend the Charles Sauriol Environmental Dinner for the  Living City alongside David Phipps, Director of Knowledge Mobilization at York University.  The event hosted by the Conservation Foundation of Greater Toronto, the Oak Ridges Moraine Land Trust, and Toronto and Region Conservation is an annual event celebrating the conservationist Charles Sauriol. The event aims not only to raise funds for conservation, but also raise awareness of the importance of conservation.

The event  recognized the Living City Award Winners of 2010. These included the Greenspace Award winners, the Glassco Family for their work focused on preserving the Oak Ridges Moraine as well as other environmental initiatives including the planting of over 1,000,000 trees and a commitment to sustainable agriculture. The Living City Award for Healthy Rivers and Shorelines was presented to Waterfront Toronto for the East Bayfront Integrated Stormwater Management System at Sherbourne Park.  The award for Sustainable Communities was presented to LoyaltyOne for their leadership in Partners in Project Green, and last, but certainly not least the W. Garfield Weston Foundation was recognized with the Living City Award for Regional Biodiversity for their support of the Monarch butterfly Teacher Network.

CC-RAI and myself would like to congratulate all the award winners and recognize the incredible job the TRCA Foundation did in hosting a fabulous event.