Growing indicators of fading biodiversity
By Drs. Robert & Sonia Vogl
President and Vice President,
Illinois Renewable Energy Association
We are frequently reminded that we are living during the sixth great extinction. Although previous extinctions occurred as a result of natural phenomena and disasters, this one is caused by one of the threatened species: humanity. As our numbers grow, other species fade. The human world population, now estimated at over 7 billion, stood at only 2.5 billion in 1950. We now consume 38 percent of the land area in the world for the production of crops. Over 97 percent of the world’s land mammals, by weight, are humans, our pets and domestic livestock, leaving less than 3 percent as wild, or natural. There are approximately 24 billion chickens – domestic birds – on the planet.
Natural ecosystems, which operated in a balance in which each species contributed to the system’s health and the health of the other species, are dwindling.
A recent article, Catastrophic shifts in ecosystems, published in the journal, Nature, refers to influences which have led to dramatic shifts in conditions in the world’s great ecosystems: “lakes, coral reefs, oceans, forests and arid lands.” These systems are naturally diverse, producing balance and resilience. As they become less diverse, they are less able to maintain themselves.
While some threats to species, such as air and water pollution, are obvious, others, such as habitat fragmentation, leading to “virtual islands,” can be just as damaging. Plants are unable to move between these islands so lack their basic needs of moisture, sunlight, and temperature and cannot thrive. While animals can move, many cannot travel the gaps between islands to satisfy their basic needs of habitat and food or interbreeding for species robustness.
While many of the human induced changes are subtle and not easily noticeable, others, such as earlier bird migrations and blooming dates for flowers, can be clearly observed by most. Worldwide tree death, while not easily comprehended, can be recognized by the fading species including elms, oaks, and ash, which people live with and love. A presentation at this year’s Illinois Renewable Energy and Sustainable Lifestyle Fair by two staff members of the Leopold Center will address changes in phenological data, or biological timing. Records were initiated by Aldo Leopold, the famed ecologist, in the 1930s, were continued until 1998 by his daughter, Nina Leopold Bradley, and are currently maintained by Center researchers.
Amphibians are the most highly threatened of all animal groups; they are extremely sensitive to environmental changes and are susceptible to many of them. While related, fewer species of reptiles are endangered. Birds in decline are sensitive to habitat degradation and loss. About 700 North American freshwater fish are in peril. Mammals, especially primates and marine mammals, are also imperiled. About one-fifth of them are slipping toward extinction.
Invertebrates, composing about 97 percent of total animal species, are also in decline. About one-third of those known are threatened. One of the best publicized ecosystems under threat, coral reefs, composed of invertebrates, will be addressed at the Fair by Philip Whitford, who has studied reefs with his students for years and will present his first-hand information.
While animals can move when their habitat is in decline, plants, the foundation of ecosystems, the base of food chains, and the source of many medicines, cannot move quickly enough to survive.
Fortunately, efforts to preserve and rehabilitate natural areas with their multiple benefits are ongoing. Excellent examples in this region include the Byron Forest Preserve with over 2,000 acres in eight sites, Nachusa Grasslands with over 3,000 acres, and holdings of the Natural Land Institute. All three maintain prairie, woodland, and wetlands. Numerous smaller sites are managed by relatively small organizations. Restorationists use seed harvesting and planting or overseeding, prescribed burns, and invasive species management as the major techniques to improve the quality of degraded sites and maintain the health of those still of high quality. They refer to natural remnants for information they need on natural areas composition.
Nachusa Grasslands has recently added a herd of bison, keystone species in North American prairies, as restorationists. They anticipate that these native animals will control excessive grass growth, expanding high-quality areas and requiring less human effort to do so. Additionally, they are protected so that they will thrive and their numbers will increase.
Representatives of these organizations will have exhibits at the Fair where interested visitors can learn more about their work and how they might become involved.
The Illinois Renewable Energy and Sustainable Lifestyle Fair will include concerns about changes in ecosystems and provide optimistic alternative strategies for coping.