Species Packing Into Biosphere 2 by Tony Burgess
Refuge Notebook • Vol. 20, No. 46 • November 23, 2018
Species packing into Biosphere 2 by Tony Burgess
Dr. Tony Burgess in the Biosphere 2 desert biome in 1993. The desert began transforming into chaparral scrubland after receiving extra rain for more than a year to increase carbon dioxide uptake.
In 1991, Biosphere 2 was launched in Oracle, Ari- spheric composition and climate in its past. Most zona. It is a 3-acre structure built to enclose seven shifts have been slow enough to allow plants andan- biomes or habitats: rainforest, coral reef, mangrove imals time to adapt and evolve as they generally be- wetlands, savanna grassland, fog desert, an agricul- came more taxonomically diverse. But five times in tural system, and living space for eight humans who the past 450 million years, more than 75% of known called themselves biospherians. It remains the largest species disappeared from the fossil record when cli- closed system ever created. mates changed too quickly. Biosphere 2 was originally designed to discover Many scientists agree we are sliding into the sixth how closed ecological systems could maintain human mass extinction, driven by human activities such as life in outer space. The first attempt to live fortwo logging, farming, overharvesting, and polluting, but years within these hopefully self-sustaining systems also by a climate rapidly warming in response to went awry when food and oxygen became scarce. The greenhouse gas emissions. The designers of Biosphere second attempt was aborted after a few months bya 2 did not envision their grand experiment might have management dispute. more relevance to our warming Earth than to coloniz- Earth, too, has experienced changes in atmo- ing space.
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I was an ecological designer of the Biosphere 2 used a synthetic approach for the humid desert biome, desert and savannah biomes, and later helped manage populating it with plants from several coastal deserts them. Now I live in Homer. in Baja California, Israel, Namibia and Chile. The biomes inside Biosphere 2 were to evolve Microbial communities are the critical foundation within nearly total material closure for 100 years, with for a biosphere, yet they are the least understood. In occasional modifications, and humans would inhabit the 1980s when we were designing Biosphere 2, tech- almost continuously as involved observers, rotating nology for assessing microbes was too crude for de- crews every two years. A century is a long time for hu- tailed inventories. However, we were certain that if mans; however, it’s only enough time to grow a young there were diverse environments inside Biosphere 2, forest or form a weakly developed soil. inoculated with soils and waters from diverse places, Why did we design so many biomes into Biosphere there would soon be well-adapted microbial commu- 2? More opportunities to learn. All we knew for cer- nities to recycle nutrients and stabilize air and water tain was that the only known biosphere, Earth, has chemistry. A similar process occurs in aquariums and many biomes which interact in creating air and water aquaponics systems, when their ecosystem “pops” into chemistries that foster life. Mostly powered by sun- a state that can process fish waste into plant nutrients. light, our planetary biosphere consumes incoming en- Establishing adaptable populations of plants and ergy to create complex, evolving, carbon-based life, di- animals posed greater challenges. Space and light en- versifying in interacting ecosystems that continuously ergy were limited in our ‘island’, hence the number recycle essential nutrients. of individual organisms had to be limited. However, We didn’t know which biomes would be best, and more individuals of each species meant fewer species there were few clues. What became clear was that could be included. So we developed a compromise an agricultural biome alone would not be adequate— design strategy. We emphasized species richness in current agricultural technology causes rapid fluxes of plants and smaller invertebrates such as roaches and carbon dioxide that destabilizes atmospheric chem- ants. In contrast, we included only a few vertebrate istry. For example, every time the soil was tilled, a species such as coqui frogs and Solomon Island skinks, large burst of carbon dioxide was released into the air. but we stocked enough individuals to ensure breeding The question that challenged us was how to cre- populations. ate a biosphere that evolved as quickly as possible, Management changes cancelled the goal of a cen- while sustaining as much diversity as possible. Fortu- tury of observation and evolution. Yet even during nately, a theory of island biogeography offered hints the few years of closure, community adaption was ev- about maximizing species richness in closed ecosys- ident. During the first closed mission, condensation tems. The most species-rich islands tend to be those on the glass dripped extra moisture into the soil, and that had once been connected to continents rather rainfall in the desert biome was substantially increased than islands that arose from volcanoes or coral reefs. to offset oxygen loss. Within two years, the desert After becoming isolated by rising sea level, these con- vegetation structure changed from open shrubland to tinental fragments (now islands) with higher species denser chaparral. Many desert plant species died, but richness adjust to the more limited resources of an is- those favored by the wetter climate allowed a rapid land. transition to better adapted vegetation. Surveys dis- Similarly, we assumed well-adapted species would covered two species new to science, a protozoan and accumulate more rapidly in Biosphere 2 if we over- a soil nematode, indicating that novel communities packed our small biomes with lots of plants and an- were forming rapidly from diverse inoculations. The imals, an idea we called “species packing.” As the fa- invertebrate food web began to organize with crazy mous ecologist Howard Odum advised us, “shovel the ants (Paratrechina) as keystone predators, similar to species in, and let extinction sort it out.” islands where this ant has been introduced. Choosing which species to colonize each biome How might such concepts apply in Alaska where proved controversial. Each biome had different de- climate is warming at twice the rate of the Lower 48? signers with differing ecological ideas. For example, Unlike previous mass extinctions, powerful technolo- the mangrove biome was constructed by transporting gies currently alter the land and its ecology. New large, intact chunks of soil with growing mangroves species are pouring in with global trade, tourism, and from the Florida coast into Biosphere 2. In contrast, I gardeners’ desires for ornamental plants. Some of
USFWS Kenai National Wildlife Refuge 93 Refuge Notebook • Vol. 20, No. 46 • November 23, 2018 these species, including earthworms, pasture grasses, ments in boreal and arctic regions? The basic ques- and agricultural weeds, have become invasive in tions are the same as those that confronted us in de- Alaska. Interactions among economic globalization, signing Biosphere 2. technological evolution, cultural evolution, climate Dr. Tony Burgess, now retired, continues to grow change and human population growth are certain to many different plants on his small farm outside cause major, disruptive changes in Alaska’s ecology. of Homer. Find more Refuge Notebook articles Might Alaskans want to learn how to assist eco- (1999–present) at https://www.fws.gov/refuge/Kenai/ logical adaptation that could sustain healthy environ- community/refuge_notebook.html.
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