September 2019 - Geospatial Ecology of Marine Megafauna Laboratory

The significance of blubber hormone sampling in conservation and monitoring of marine mammals

By: Alexa Kownacki, Ph.D. Student, OSU Department of Fisheries and Wildlife, Geospatial Ecology of Marine Megafauna Lab

Marine mammals are challenging to study for many reasons, and specifically because they inhabit the areas of the Earth that are uninhabited by people: the oceans. Monitoring marine mammal populations to gather baselines on their health condition and reproductive status is not as simple as trap and release, which is a method often conducted for terrestrial animals. Marine mammals are constantly moving in vast areas below the surface. Moreover, cetaceans, which do not spend time on land, are arguably the most challenging to sample.

One component of my project, based in California, USA, is a health assessment analyzing hormones of the bottlenose dolphins that frequent both the coastal and the offshore waters. Therefore, I am all too familiar with the hurdles of collecting health data from living marine mammals, especially cetaceans. However, the past few decades have seen major advancements in technology both in the laboratory and with equipment, including one tool that continues to be critical in understanding cetacean health: blubber biopsies.

Biopsy dart hitting a bottlenose dolphin below the dorsal fin. Image Source: NMFS

Blubber biopsies are typically obtained via low-powered crossbow with a bumper affixed to the arrow to de-power it once it hits the skin. The arrow tip has a small, pronged metal attachment to collect an eraser-tipped size amount of tissue with surface blubber and skin. I compare this to a skin punch biopsies in humans; it’s small, minimally-invasive, and requires no follow-up care. With a small team of scientists, we use small, rigid-inflatable vessels to survey the known locations of where the bottlenose dolphins tend to gather. Then, we assess the conditions of the seas and of the animals, first making sure we are collecting from animals without potentially lowered immune systems (no large, visible wounds) or calves (less than one years old). Once we have photographed the individual’s dorsal fin to identify the individual, one person assembles the biopsy dart and crossbow apparatus following sterile procedures when attaching the biopsy tips to avoid infection. Another person prepares to photograph the animal to match the biopsy information to the individual dolphin. One scientist aims the crossbow for the body of the dolphin, directly below the dorsal fin, while the another photographs the biopsy dart hitting the animal and watches where it bounces off. Then, the boat maneuvers to the floating biopsy dart to recover the dart and the sample. Finally, the tip with blubber and skin tissue is collected, again using sterile procedures, and the sample is archived for further processing. A similar process, using an air gun instead of a crossbow can be viewed below:

GEMM Lab members using an air gun loaded with a biopsy dart to procure marine mammal blubber from a blue whale in New Zealand. Video Source: GEMM Laboratory.

Part of the biopsy process is holding ourselves to the highest standards in our minimally-invasive technique, which requires constant practice, even on land.

Alexa practicing proper crossbow technique on land under supervision. Image Source: Alexa Kownacki

Blubber is the lipid-rich, vascularized tissue under the epidermis that is used in thermoregulation and fat storage for marine mammals. Blubber is an ideal matrix for storing lipophilic (fat-loving) steroid hormones because of its high fat content. Steroid hormones, such as cortisol, progesterone, and testosterone, are naturally circulating in the blood stream and are released in high concentrations during specific events. Unlike blood, blubber is less dynamic and therefore tells a much longer history of the animal’s nutritional state, environmental exposure, stress level, and life history status. Blubber is the cribs-notes version of a marine mammal’s biography over its previous few months of life. Blood, on the other hand, is the news story from the last 24 hours. Both matrices serve a specific purpose in telling the story, but blubber is much more feasible to obtain from a cetacean and provides a longer time frame in terms of information on the past.

A simplified depiction of marine mammal blubber starting from the top (most exterior surface) being the skin surface down to the muscle (most interior). Image Source: schoolnet.org.za

I use blubber biopsies for assessing cortisol, testosterone, and progesterone in the bottlenose dolphins. Cortisol is a glucocorticoid that is frequently associated with stress, including in humans. Marine mammals utilize the same hypothalamic-pituitary-adrenal (HPA) axis that is responsible for the fight-or-flight response, as well as other metabolic regulations. During prolonged stressful events, cortisol levels will remain elevated, which has long-term repercussions for an animal’s health, such as lowered immune systems and decreased ability to respond to predators. Testosterone and progesterone are sex hormones, which can be used to indicate sex of the individual and determine reproductive status. This reproductive information allows us to assess the population’s composition and structure of males and females, as well as potential growth or decline in population (West et al. 2014).

Alexa using a crossbow from a small boat off of San Diego, CA. Image Source: Alexa Kownacki

The coastal and offshore bottlenose dolphin ecotypes of interest in my research occupy different locations and are therefore exposed to different health threats. This is a primary reason for conducting health assessments, specifically analyzing blubber hormone levels. The offshore ecotype is found many kilometers offshore and is most often encountered around the southern Channel Islands. In contrast, the coastal ecotype is found within 2 kilometers of shore (Lowther-Thieleking et al. 2015) where they are subjected to more human exposure, both directly and indirectly, because of their close proximity to the mainland of the United States. Coastal dolphins have a higher likelihood of fishery-related mortality, the negative effects of urbanization including coastal runoff and habitat degradation, and recreational activities (Hwang et al. 2014). The blubber hormone data from my project will inform which demographics are most at-risk. From this information, I can provide data supporting why specific resources should be allocated differently and therefore help vulnerable populations. Further proving that the small amount of tissue from a blubber biopsy can help secure a better future for population by adjusting and informing conservation strategies.

Literature Cited:

Hwang, Alice, Richard H Defran, Maddalena Bearzi, Daniela. Maldini, Charles A Saylan, Aime ́e R Lang, Kimberly J Dudzik, Oscar R Guzo n-Zatarain, Dennis L Kelly, and David W Weller. 2014. “Coastal Range and Movements of Common Bottlenose Dolphins (Tursiops Truncatus) off California and Baja California, Mexico.” Bulletin of the Southern California Academy of Sciences 113 (1): 1–13. https://doi.org/10.3390/toxins6010211.

Lowther-Thieleking, Janet L., Frederick I. Archer, Aimee R. Lang, and David W. Weller. 2015. “Genetic Differentiation among Coastal and Offshore Common Bottlenose Dolphins, Tursiops Truncatus, in the Eastern North Pacific Ocean.” Marine Mammal Science 31 (1): 1–20. https://doi.org/10.1111/mms.12135.

West, Kristi L., Jan Ramer, Janine L. Brown, Jay Sweeney, Erin M. Hanahoe, Tom Reidarson, Jeffry Proudfoot, and Don R. Bergfelt. 2014. “Thyroid Hormone Concentrations in Relation to Age, Sex, Pregnancy, and Perinatal Loss in Bottlenose Dolphins (Tursiops Truncatus).” General and Comparative Endocrinology 197: 73–81. https://doi.org/10.1016/j.ygcen.2013.11.021.

What does it mean to be an effective science communicator?

By Dominique Kone, Masters Student in Marine Resource Management

To succeed as a scientist, you not only need to be well-trained in the scientific method, but also be familiar with the standards and practices in your discipline. While many scientists are skilled in the production of scientific information, fewer are as well-prepared to disseminate and communicate that information to diverse audiences. As a graduate student, learning effective science communication is one of my top priorities because I believe scientific information can and should be accessible to everyone. As I’ve been building and expanding upon my own communication toolbox, I constantly ask myself, what is effective science communication?

Simply put, communication can be thought of as the two-way transfer of information and knowledge. On one side, information is broadcasted and amplified out into the world, and on the other side, that information is received and understood, ideally. If communicating were this easy, people would never have to worry about being misinterpreted. Yet, this ideal is far from reality, and information is oftentimes misconstrued and/or ignored. This scenario is quite common when scientists communicate technical concepts or findings to non-scientists, either due to differences in communication styles or terminology use. In connecting with these types of audiences, I think effective science communication is a function of three key qualities: intentionality, creativity, and knowledge.

Intentionality

When scientists communicate information, being intentional with what they say and when they say it, can greatly influence how messages resonate with their audience. There’s often a big disconnect between the very specific scientific terms scientists use and the terms their non-technical audiences use. One way scientists can bridge this disconnect and be more intentional (thoughtful), is with word-choice. When scientists change their words, this doesn’t mean they “dumb down” their presentations; rather, they substitute words to better explain concepts in terms the audience easily understands. For example, if I tell the public “I’m predicting sea otter populations at carrying capacity in Oregon using a Bayesian habitat model”, this sentence has three jargon words (carrying capacity, Bayesian, model) that likely mean nothing to this audience. Instead, what I say is, “I’m predicting how many sea otters could live in Oregon based on available habitat”. Now I’m speaking in terms that resonate with my audience, and I have effectively made the same point. An intentional science communicator knows how to deliver information to meet their audience’s ability to take in and process that information.

Creativity

Scientists typically follow structured and defensible protocols when conducting analyses. Far fewer standards apply to how they communicate that research, which can free them up to be more creative in their delivery. One way scientists can be both intentional and creative is by using analogies, examples, or metaphors. When I give talks, I always talk about the high metabolism of sea otters (30% of their own body weight in food, daily) (Costa 1978, Riedman & Estes 1990). Most researchers seem intrigued by this fact, but anyone younger than the age of 10, honestly, could care less. To catch their attention, I always follow up this fact by estimating how many pizza slices I would need to eat to reach that daily food requirement, based on my own weight (230 pizza slices, if you’re curious). By using this analogy, my young audience not only understands my point, but they’re now way more interested because they can’t fathom a human eating that much pizza. It’s a simple comparison, but effective.

Creativity can also be applied to the different ways scientific information is delivered. Scientists regularly publish their work in peer-review scientific journals to reach other scientists. But they also produce short reports and fact sheets to briefly summarize studies for managers or policy-makers. They hold events or workshops to engage stakeholders. They use blogs, webpages, and YouTube to reach the broader public. They even use Twitter to share papers! Scientists do so much more than just publishing their work, and they have several options for delivering and communicating their research. All these different options create more opportunities for scientists to experiment and find new and exciting ways to deliver their science.

A stoic scientist communicating to the masses. Source: Dave Allen via NIWA.

Knowledge

It’s important for scientists to be knowledgeable about their subjects when communicating, but they can’t know everything. Rather, I think a more reasonable goal is for scientists to be comfortable and prepared to say what they know and what they don’t know. Scientists have a thirst for knowledge, but some communicate false information because they have a drive to answer every question they’re asked. They can sometimes get into trouble when they’re asked to talk about something they’re less familiar with. When asked a difficult question, I’ve witnessed a lot of scientists say, “I don’t know”, or, “I don’t know, but I could speculate [insert answer] based on other information”. This response allows them to answer the question, while also being truthful. The alternative could have real negative implications (e.g. a certain President spreading false information about a dangerous hurricane).

Aside from factual knowledge, contextual knowledge is underappreciated in science communication, but can be vitally important. Some management issues are politically contentious, and effective science communicators can play vital roles in those management processes or actions. One study found that by scientists engaging with stakeholders in the planning process for renewable energy development along the coast of Maine, community members felt the development planning process was being conducted in the most effective manner (Johnson et al. 2015). In this example, a seemingly contentious situation was defused because scientists understood the political and social landscape, and were able to carefully communicate with stakeholders before any management actions took place. Scientists are not required to engage with stakeholders to this degree, but being sensitive to the broader (political, social, cultural, economic) environment in which those stakeholders live and operate can help them better target your messages and relieve potential tension.

GEMM Lab booth at Hatfield Marine Science Day! Source: Leila Lemos.

These three qualities (intentionality, creativity, and knowledge) are not meant to serve as hard, fast science communication rules. Instead, these are simply some qualities I’ve observed in other scientists skilled in effective communication. Scientists don’t automatically enter this space as expert communicators. For those that are great at it, it probably took some time and practice to hone their skills and find their own voice. It might come more naturally to some scientists, but I would argue most – like myself – have to work really hard to develop those skills. As I progress through my career, I’m excited to develop my own skills in effective science communication, and perhaps discover new and exciting approaches along the way.

References:

Costa, D. P. 1978. The ecological energetics, water, and electrolyte balance of the California sea otter (Enhydra lutris). Ph.D. dissertation, University of California, Santa Cruz.

Reidman, M. L. and J. A. Estes. 1990. The sea otter (Enhydra lutris): behavior, ecology, and natural history. United States Department of the Interior, Fish and Wildlife Service, Biological Report. 90: 1-126.

Johnson, T. R., Jansujwiez, J. S., and G. Zydlewski. 2015. Tidal power development n Maine: stakeholder identification and perceptions of engagement. Estuaries and Coasts 38: S266-S278.

The Seascape of Fear: What are the ecological implications of being afraid in the marine environment?

By Dawn Barlow, PhD student, OSU Department of Fisheries and Wildlife, Geospatial Ecology of Marine Megafauna Lab

In the GEMM Lab, our research focuses largely on the ecology of marine top predators. Inherent in our work are often assumptions that our study species—wide-ranging predators including whales, dolphins, otters, or seabirds—will distribute themselves relative to their prey. In order to make a living in the highly patchy and dynamic marine environment, predators must find ways to predictably locate and exploit prey resources.

But what about the prey? How do the prey structure themselves relative to their predators? This question is explored in depth in a paper titled “The Landscape of Fear: Ecological Implications of Being Afraid” (Laundre et al. 2010), which we discussed in our most recent lab meeting. When wolves were re-introduced in Yellowstone, the elk increased their vigilance and altered their grazing patterns. As a result, the plant community was altered to reflect this “landscape of fear” that the elk move through, where their distribution not only reflected opportunities for the elk to eat but also the risk of being eaten.

Translating the landscape of fear concept to the marine environment is tricky, but a fascinating exercise in ecological theory. We grappled with drawing parallels between the example system of wolves, elk, and vegetation and baleen whales, zooplankton, and phytoplankton. Relative to grazing mammals like elk, the cognitive abilities of zooplankton like krill, copepods, and mysid might pale in comparison. How could we possibly measure “fear” or “vigilance” in zooplankton? The swarming behavior of mysid and krill into dense patches is a defense mechanism—the strategy they have evolved to lessen the likelihood that any one of them will be eaten by a predator. I would posit that the diel vertical migration (DVM) of zooplankton is a manifestation of fear, at least on some level. DVM occurs over the course of each day, with plankton in pelagic ecosystems migrating vertically in the water column to avoid predators by hiding at depth during the daylight hours, and then swimming upward to feed on phytoplankton under the cover of darkness. I won’t speculate any further on the intelligence of zooplankton, but the need to survive predation has driven them to evolve this effective evolutionary strategy of hiding in the ocean’s twilight zone, swimming upward to feed only after dark so that they’re less likely to linger in spaces occupied by predators.

A swarm of mysid along the Oregon Coast. How does fear of predation by gray whales or rockfish drive the distribution of zooplankton in this shallow, nearshore system? Photo by Dawn Barlow.
A rock covered in purple urchin on the Oregon Coast. In the absence of their major predators (sea otters and sea stars), are urchins able to thrive in an environment with less fear of predation? Photo by Dawn Barlow.
A blue whale lunges on a dense aggregation of krill in New Zealand. In this image, you can actually see the krill “fleeing”, jumping out of the water in an attempt to escape the whale’s mouth. Drone piloted by Todd Chandler.

Laundre et al. (2010) present a visual representation of the landscape of fear (Fig. 1, reproduced below), where as an animal moves through space (represented as distance in meters or kilometers, for example), they also move through varying levels of predation risk. Environmental gradients (temperature, for example) tend to be much more stable across space in terrestrial ecosystems such as in the Yellowstone example from the paper. I wonder whether the same concept and visual depiction of a landscape of fear could be translated as risk across various environmental gradients, rather than geographic distances? In this proposed illustration, a landscape of fear would vary based on gradients of environmental conditions rather than geographic space. Such a shift in spatial reference —from geographic to environmental space—might make the model more applicable in the dynamic ocean ecosystems that we study.

What about cases when the predators we study become prey? One example we discussed was gray whales migrating from breeding lagoons in Mexico to feeding grounds in the Bering Sea. Mother-calf pairs hug the coastline tightly, by no means taking the most direct route between locations and adding considerable travel distance to their migration. The leading hypothesis is that mother gray whales take the coastal route to minimize the risk that their calves will fall prey to killer whale attacks. Are there other cases where the predators we study operate in a seascape of fear that we do not yet understand? Likely so, and the predators’ own seascape of fear may account for cases when we cannot explain predator distribution simply by their prey and their environment. To take this a step further, it might be beneficial not only to think of predation risk as only the potential to be eaten, but expand our definition to include human disturbance. While humans may not directly prey on marine predators, the disturbance from human activity in the ocean likely creates a layer of fear which animals must navigate, even in the absence of actual predation.

Our lively lab meeting discussion prompted me to look into how the landscape of fear model has been applied to the highly dynamic and intricate marine environment. In a study examining predator-prey dynamics of three species of marine mammals—bottlenose dolphins, harbor seals, and dugongs—Wirsing et al. (2007) found that in all three cases, the study species spent less time in more desirable prey patches or decreased riskier behavior in the presence of predators. Most studies in marine ecology are observational, as we rarely have the opportunity to manipulate our study system for experimental design and hypothesis testing. However, a study of coral reefs in the Florida Keys conducted by Catano et al. (2015) used fabricated predators—decoys of black grouper, a predatory fish—to investigate the influence of fear of predation on the reef system. What they found was that herbivorous fish consumed significantly less and fed at a much faster rate in the presence of this decoy predator. The grouper, even in decoy form, created a “reefscape of fear”, altering patterns in herbivory with potential ramifications for the entire ecosystem.

My takeaway from our discussion and my musings in this week’s blog post is that predator and prey distribution and behavior is highly interconnected. While predators distribute themselves to maximize their ability to find a meal, their prey respond accordingly by balancing finding a meal of their own with minimizing the risk that they will be eaten. Ecology is the study of an ecosystem, which means the questions we ask are complicated and hierarchical, and must be considered from multiple angles, accounting for biological, environmental, and behavioral elements to name a few. These challenges of studying ecosystems are simultaneously what make ecology fascinating, and exciting.

References:

Laundré, J. W., Hernández, L., & Ripple, W. J. (2010). The landscape of fear: ecological implications of being afraid. Open Ecology Journal, 3, 1-7.

Catano, L. B., Rojas, M. C., Malossi, R. J., Peters, J. R., Heithaus, M. R., Fourqurean, J. W., & Burkepile, D. E. (2016). Reefscapes of fear: predation risk and reef hetero‐geneity interact to shape herbivore foraging behaviour. Journal of Animal Ecology, 85(1), 146-156.

Wirsing, A. J., Heithaus, M. R., Frid, A., & Dill, L. M. (2008). Seascapes of fear: evaluating sublethal predator effects experienced and generated by marine mammals. Marine Mammal Science, 24(1), 1-15.

Burning it down

By Leila S. Lemos, PhD Candidate in Wildlife Sciences, Fisheries and Wildlife Department, OSU

As you might know, the GEMM Lab (Geospatial Ecology of MARINE Megafauna Laboratory) researches the marine environment, but today I am going to leave the marine ecosystem aside and I will discuss the Amazon biome. As a Brazilian, I cannot think of anything else to talk about this week than the terrifying fire that is burning down the Amazon forest in this exact minute.

For some context, the Amazon biome is known as the biome with the highest biodiversity in the world (ICMBio, 2019). It is the largest biome in Brazil, accounting for ~49% of the Brazilian territory. This biome houses the biggest tropical forest and hydrographic basin in the world. The Amazon forest also extends through eight other countries: Bolivia, Colombia, Ecuador, Guiana, French Guiana, Peru, Suriname and Venezuela. To date, at least 40,000 plant species, 427 mammals, 1,300 birds, 378 reptiles, more than 400 amphibians, around 3,000 freshwater fishes, and around 100,000 invertebrate species have been described by scientists in the Amazon, comprising more than 1/3 of all fauna species on the planet (Da Silva et al. 2005, Lewinsohn and Prado 2005). And, these numbers are likely to increase; According to Patterson (2000), one new genus and eight new species of Neotropical mammals are discovered each year in the region.

I feel very connected to the Amazon as I worked as an environmental consultant and field coordinator in 2014 and 2015 (Figs. 1 and 2) along the Madeira river (or “Wood” river) in Rondonia, Brazil (Fig. 3). I monitored Amazon river dolphins (Inia geoffrensis; Fig. 4), a species considered endangered by the IUCN Red List in 2018 (Da Silva et al. 2018). The Madeira river originates in Bolivia and flows into the great Amazon river, comprising one of its main tributaries (Fig. 3).

Figure 1: Me, working along the Madeira river, Rondonia, Brazil, in 2015.
Source: Laura K. Honda, 2015.

Figure 2: Me, helping to rescue a sloth from the Madeira river, Rondonia, Brazil, in 2014.
Source: Roberta Lanziani, 2014.

Figure 3: The Amazon hydrographic basin, with the Madeira river highlighted.
Source: Wikipedia, 2019.

Here is also a video where you can see some Amazon river dolphins along the Madeira river:

Source: Leila S. Lemos, 2014; 2015.

In addition to the dolphins, I witnessed the presence of many other fauna specimens like birds (including macaws and parrots), monkeys, alligators and sloths (Fig. 5). The biodiversity of the Amazon is unquestionable.

Figure 5: Macaws (Ara chloropterus), parrots (Amazona sp.) and the Guariba monkey or brown howler (Allouatta guariba) along the Madeira river, Rondonia, Brazil.
Source: Leila S. Lemos

Other than its great biodiversity, the Amazon is known as the “lungs of the Earth”, which is an erroneous statement since plants consume as much oxygen as they produce (Malhi et al. 2008, Malhi 2019). But still, the Amazon forest is responsible for 16% of the oxygen produced by photosynthesis on land and 9% of the oxygen on the global scale (Fig. 6). This seems a small percentage, but it is still substantial, especially because the plants use carbon dioxide during photosynthesis, which accounts for a 10% reduction of atmospheric carbon dioxide. Thus, imagine if there was no Amazon rainforest. The rise in carbon dioxide would be enormous and have serious implications on the global climate, surpassing safe temperature boundaries for many regions.

Figure 6: Total photosynthesis of each major land biome. This value is multiplied by 2.67 to convert to total oxygen production. Hence total oxygen production by photosynthesis on land is around 330 Pg of oxygen per year. The Amazon (just under half of the tropical forests) is around 16% of this, around 54 Pg of oxygen per year.
Source: Malhi 2019.

Unfortunately, this scenario is not really far from us. Even though deforestation indices have fallen in the last 15 years, fire incidence associated with droughts and carbon emissions have increased (Aragão et al. 2018; Fig. 7).

Figure 7: Linear trends (2003–2015) of annual (a) deforestation rates, and (b) active fires counts in the Brazilian Amazon. Red circles indicate the analyzed drought years by Aragão et al. (2018).
Source: Aragão et al. 2018.

Since August 2019, the Amazon forest has experienced extreme fire outbreaks (Figs. 8 and 9). Around 80,000 fires occurred only in 2019. Despite 2019 not being an extreme drought year, the period of January-August 2019 is characterized by an ~80% increase in fires compared to the previous year (Wagner and Hayes 2019). The intensification of the fires has been linked to the Brazilian President’s incentive to “open the rainforest to development”. Leaving politics aside, the truth is that the majority of these fires have been set by loggers and ranchers seeking to clear land to expand the agro-cattle area (Yeung 2019).

Figure 8: The Amazon in July 28: just clouds; and in August 22: choked with smoke.
Source: NOAA, in: Wagner and Hayes, 2019.

Figure 9: Images showing some of the destruction caused by the fires in the Amazon region in 2019.
Source: Buzz Feed News 2019, Sea Mashable 2019.

Here you can see some videos showing the extension of the problem:

Video 1 – by NBC News:

Video 2 – a drone footage by The Guardian:

I consider myself lucky for the opportunity to have worked in the Amazon rainforest before these chaotic fires have destroyed so much biodiversity. The Amazon is a crucial home for countless animal and plant species, and to ~900,000 indigenous individuals that live in the region. They are all at risk of losing their homes and lives. We are all at risk of global warming.

References

Aragão LEOC, Anderson LO, Fonseca MG, Rosan TM, Vedovato LB, Wagner FH, Silva CVJ, Silva Junior CHL, Arai E, Aguiar AP, Barlow J, Berenguer E, Deeter MN, Domingues LG, Gatti L, Gloor M, Malhi Y, Marengo JA, Miller JB, Phillips OL, and Saatchi S. 2018. 21^stCentury drought-related fires counteract the decline of Amazon deforestation carbon emissions. Nature Communications 9(536):1-12.

Buzz Feed News. 2019. These Heartbreaking Photos Show The Devastation Of The Amazon Fires. Retrieved 1 September 2019 from https://www.buzzfeednews.com/article/gabrielsanchez/photos-trending-devastation-amazon-wildfire

Da Silva JMC, Rylands AB, and Da Fonseca GAB. 2005. The Fate of the Amazonian Areas of Endemism. Conservation Biology 19(3):689-694.

Da Silva V, Trujillo F, Martin A, Zerbini AN, Crespo E, Aliaga-Rossel E, and Reeves R. 2018. Inia geoffrensis. The IUCN Red List of Threatened Species 2018: e.T10831A50358152. http://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T10831A50358152.en. Downloaded on 27 August 2019.

ICMBio. 2019. Amazônia. Retrieved 26 August 2019 from http://www.icmbio.gov.br/portal/unidades deconservacao/biomas-brasileiros/amazonia

Lewinsohn TM, and Prado PI. 2005. How Many Species Are There in Brazil? Conservation Biology 19(3):619.

Malhi Y. 2019. does the amazon provide 20% of our oxygen? Travels in ecosystem science. Retrieved 29 August 2019 from http://www.yadvindermalhi.org/blog/does-the-amazon-provide-20-of-our-oxygen

Malhi Y., Roberts JT, Betts RA, Killeen TJ, Li W, Nobre CA. 2008. Climate Change, Deforestation, and the Fate of the Amazon. Science 319:169-172.

Patterson BD. 2000. Patterns and trends in the discovery of new Neotropical mammals. Diversity and Distributions, 6, 145-151.

Sea Mashable. 2019. The Amazon forest is burning to the ground. Here’s how it happened and what you can do to help. Retrieved 1 September 2019 from https://sea.mashable.com/culture/5813/the-amazon-forest-is-burning-to-the-ground-heres-how-it-happened-and-what-you-can-do-to-help

Wagner M, and Hayes M. 2019. Wildfires rage in the Amazon. CNN. Retrieved 26 August 2019 from https://www.cnn.com/americas/live-news/amazon-wildfire-august-2019/index.html

Wikipedia. 2019. Madeira river. Retrieved 29 August 2019 from https://en.wikipedia.org/wiki/Madeira_River

Yeung J. 2019. Blame humans for starting the Amazon fires, environmentalists say. CNN. Retrieved 26 August 2019 from https://www.cnn.com/2019/08/22/americas/amazon-fires-humans-intl-hnk-trnd/index.html

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