Living Planet?

Biodiversity is the totality of all inherited variation in the life forms of Earth, of which we are one species. We study and save it to our great benefit. We ignore and degrade it to our great peril.” — E.O. Wilson

State of global biodiversity

Today the World Wildlife Fund - Living Planet Report 2014 - was released. This latest edition shows that since 1970 population sizes of vertebrates (mammals, birds, reptiles, amphibians and fish) have dropped by 52%. Many see this as yet another sign of that we might be in the middle of a sixth mass extinction event in Earth’s history. This post will therefore deal with the topic of biodiversity.

What is biodiversity?

Biological diversity (i.e. biodiversity) reflects the number, variety and variability of living organisms. It includes diversity within species, between species, and among ecosystems. The concept also covers how this diversity changes from one location to another and over time. Indicators such as the number of species in a given area can help in monitoring certain aspects of biodiversity. When one wants to understand the health of an entire ecosystem, however, some species may be more important than others in the sense that they provide a key function within the entire system. Ecologist often refer to such species as keystone species. Take for example the otter. They are considered a keystone species because of their critical importance to the health and stability of nearshore marine ecosystems. Otters eat sea urchins and other invertebrates that graze on giant kelp. Without sea otters, these grazing animals can destroy kelp forests and consequently the wide diversity of animals that depend upon kelp habitat for survival (Fig. 1). Additionally, kelp forests protect coastlines from storm surge and absorb carbon dioxide from the atmosphere.

Fig. 1 The difference in a marine ecosystem with and without Sea otters


Some of the main threats to biodiversity include: invasive species, climate change, nutrient loading and pollution, habitat change, and overexploitation. These are direct drivers of change, but there are also indirect drivers of change. Such as demographics, urbanization, transportation, agriculture, trade and many more. With higher interconnectivity on the planet, species loss may occur at a faster rate. In a recent study Lenzen et al. (2012) showed that some 30% of biodiversity threats could be attributed to international trade by mapping out supply chains around the globe (Fig. 2).

Fig. 2 Example of flow map of species threats caused by trade

Source: Lenzen et al. 2012

What defines a mass extinction?

Of the four billion species estimated to have evolved on the Earth over the last 3.5 billion years, some 99% died out (Novacek, 2001). Extinctions are common but normally it is balanced by speciation. Sometimes, however, the balance wavers such that extinction rates become elevated. Palaeontologists characterize mass extinctions as times when the Earth loses more than 75% of its species in a geologically short interval (due to e.g. super-eruptions, impacts of asteroids, global climate changes, continent drifts), as has happened only five times in the past 540 million years (Barnosky et al., 2011). Lately biologists have been suggesting that a sixth mass extinction may be under way. By comparing the rates and amounts of extinction during those earlier events with the range of species losses over the past few centuries in human times, scientist find a similar trend. According to evolutionists like E.O. Wilson and N. Eldredge we thus have evidence that humans are now causing a mass extinction. Through a mix of impacting activities such as habitat destruction, overpopulation, chemical pollution, overexploitation of resources etc. humans have produced the conditions for a serious biodiversity crisis. According to an article in Nature (2011), Earth could reach the mass extinction levels (75%) within just a few centuries if current threats to many species are not alleviated (Barnosky et al., 2011).

Fig. 3 Graphic illustration of threatened species globally
graphics biodiversity loss
Source: NYT graphics editor Bill Marsh


Here I want to make a case for the amphibians of the planet since they are some of the most vulnerable and endangered, and people generally ignore them. The latest figures from the International Union Conservation of Nature (IUCN) Red List of Threatened Species show that there are nearly as many threatened species of amphibians (30%) as birds (12.5%) and mammals (20.6%) combined ( Most of the world’s amphibian species are located in tropical regions, especially the Amazon Rainforest (Fig. 4). In the past three decades declines in populations of amphibians have occurred worldwide due to for example: habitat destruction, pollution & pesticides, disease, and changing precipitation patterns.

Fig. 4 Global assessment (2004)

In Sweden all native amphibians and reptiles are protected by law (2007:845) with the conditions not to kill, harm, capture or destroy their habitat. Naturskyddsföreningen and SLU have nominated 2014 to be the year of the frog, focusing on collecting data on amphibians and educating the public. Many of our frogs in the South are critically endangered while others can be found nation wide.

Why it matters

Biodiversity underpins ecosystem functioning and the provision of ecosystem services. Ecosystem services such as water purification, pollination, storm protection, nutrient cycling, and climate regulation are essential for human well-being. Undermining diversity of life on Earth thus implies undermining our own well-being. Moreover, according to some studies (e.g. TEEB, 2010) there is a strong link between biodiversity loss and poverty. Why? Because the world’s poor, especially subsistence farmers and pastoralists are the first to suffer from the loss of free services provided by ecosystems and biodiversity. In rich countries people substitute natural nutrient cycling, pest control and pollination by buying expensive fertilizers, pesticides and renting bees/pollinating by hand. Because we don't value the services nature provides for us we often end up in a position where we have to pay more to restore ecosystems than if we had used preventive measures from the beginning. This is the case with the Baltic Sea which is today home to seven of the world's 10 largest marine dead zones due to eutrophication and overfishing leading to hypoxia. Trying to restore parts of the Baltic Sea to it's former conditions is a complex issue and attempts have yet to succeed. And for those who think Sweden is such a environmentally sound country, perhaps you should read the Living Planet Report (2014) which states that Sweden climbed from place 13 to 10 on the list over countries average ecological footprint in the world. Now Swedes need 3,7 planets to satisfy their lifestyle.


Out of the ashes into the fire

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