Biodiversity (Variety) is the spice of life

In his encyclical, Laudato Sí, Pope Francis speaks of the loss of biodiversity in the world today. Biodiversity refers to the number of different species of living organisms that inhabit our planet. 

More than 1.5 million species are known to science. Estimates of the number of species actually on the planet range from 10 to 100 million. New species are being discovered daily. In fact, about 18,000 new species were discovered last year. Many are found in remote areas of rainforests and the oceans, but some are found through new fossil discoveries, and even in existing collections of organisms that haven’t been analyzed yet. New species begin to appear through the processes of evolution and speciation while extinction has always occurred as well. 

According to the Smithsonian Institute 99.9 percent of all species that have lived on the earth are now extinct. Their demise has been brought about by floods, volcanoes, earthquakes, sea level rise, changes in climate, and even, in the case of the dinosaurs, meteoric impacts. Studies of the past have revealed evidence of five mass extinctions over the past 400 million years. In each event we have lost between 76 percent and 96 percent of the species living on the planet.

Since the last glaciation period about 20,000 to 10,000 years ago, it is humans who have become the dominant factor in the loss of species due to over-hunting, habitat destruction, pollution and competition resulting from the introduction of non-native, or invasive species into an area which outcompete the native species for available resources. What the pope wants us to be aware of is that, “the Earth’s resources are being plundered due to our short-sighted approaches to the economy, commerce, and production.” We are currently losing species to extinction at a rapid rate.

So why is biodiversity so important? In the natural world, the larger the number of species the more resilient the ecosystem is to the effects of environmental changes. If the changes cause the loss of some species, the genetic variation in other species may allow them to now prosper and take the place of the lost species in the food web. In ecosystems with low biodiversity the ecosystem can collapse if another species cannot take over the ecological niche, or role in the ecosystem, of the lost species. 

Ecosystems in areas that are stable over long periods of time with few major environmental changes, such as rainforests, tend to have developed more niches, and have greater biodiversity. Areas that experience geological changes, such as earthquakes, floods, fires, ice formation, and isolation create situations where only a few species can survive the stresses of these changes or fewer species inhabit an area, as in the case of islands. Under these conditions biodiversity is lower. 

The pope expresses his concern for the loss of species that we have yet to discover because they could hold valuable genetic traits that would have made them valuable as human resources for food, or for medicines, or other uses. He wants us to see that these species have value in themselves, whether or not they are of direct use to us as resources. The pope states that “each year sees the disappearance of thousands of plant and animal species which we will never know, which our children will never see, because they have been lost forever. The great majority became extinct for reasons related to human activity. Because of us, thousands of species will no longer give glory to God by their very existence, nor convey their message to us. We have no such right.”

The pope emphasizes the need for much forethought when we look to change an existing natural area to one that suits our particular economic needs. He states that, “a sober look at our world shows that the degree of human intervention, often in the service of business interests and consumerism, is actually making our earth less rich and beautiful, ever more limited and grey, even as technological advances and consumer goods continue to abound limitlessly. We seem to think that we can substitute an irreplaceable and irretrievable beauty with something that we have created ourselves.” Our urban sprawl into undisturbed areas and pollution give testimony to this. The current destruction of the rich biodiverse rainforests in Borneo to create plantations to grow a single crop, or monoculture, for the production of palm oil, is an example of this. This is one of the few remaining wild habitats of the orangutan, considered the most intelligent of the great apes. They, along with their habitat, are being lost. Our own early agricultural techniques and monoculture of corn and wheat decimated the great plains species. The dust bowl conditions of the 1930s were the result.

The pope tells us that we need to learn how to lessen our negative impact on habitats. When we divide up areas so that animals, which once freely roamed across a region, are now cut off from other members of their species, their populations suffer due to a reduction in genetic diversity, loss of area to gather food, and lower numbers available for reproductive success. “Biological Corridors” can be created which allow the organisms to migrate from one area to another and stay connected. Tunnels under highways can also achieve this. 

In our own area Massachusetts has created the 14,000-acre Southeastern Massachusetts Bioreserve precisely for the purpose of providing connected habitat for the rich populations of organisms that live there. Our National Park Service, celebrating 100 years of existence this year, has set aside millions of acres in 59 national parks, to try to preserve areas so that we can see the beauty and majesty of these natural areas and allow the plants and animals to live as they always have. The Wilderness Act, passed in 1964, offers the highest degree of land protection, by allowing no roads, vehicles, or permanent structures in the designated area. After signing this Act into law, President Lyndon Johnson stated, “If future generations are to remember us with gratitude rather than contempt, we must leave them a glimpse of the world as it was in the beginning, not just after we got through with it.”

Biodiversity is part of the complex natural systems which have functioned in harmony for thousands, and is some cases, millions of years prior to our appearance on the planet. The pope reminds us that “because all creatures are connected, each must be cherished with love and respect, for all of us as living creatures are dependent on one another.” 

Anchor columnist Professor Rak is a Fall River native and a parishioner of St. Mary’s Parish in Fall River. He has been a professor of Environmental Technology and coordinator of the Environmental Science and Technology Program at Bristol Community College in Fall River for 18 years. He earned a bachelor’s degree in biology from Holy Cross College in Worcester, and a master’s degree in marine biology from UMass Dartmouth. rrak@verizon.net


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