Biosphere 2's desert biome was designed to simulate an arid desert scrub ecosystem in a coastal climate with erratic winter rainfall and summer drought. Excessive rain and relatively low evapotranspiration during the initial two-year closure resulted in a dense scrub invaded by grasses. Conversion to a Mediterranean scrub woodland was initiated in 1994, but subsequently climate parameters were changed to simulate more arid conditions. Current management practices are intended to favor arid-adapted species and discourage grasses with C4 photosynthetic pathways.
Soils were constructed to simulate those found in arid places ranging from immature dune sand to profiles with clay, carbonate, and salt accumulations. Mini-rhizotron viewing tubes were installed in the dune, to allow periodic observation of root growth and mesofauna. A playa was designed to simulate seasonally flooded areas where salt accumulates. This area has been almost completely overgrown by saltbushes (Atriplex cinerea). A simulated tinaja of artificial rock supports freshwater organisms that can withstand periodic desiccation.
Plant species diversity has declined since assembly, as might be expected. The substantial changes in management goals and climate, together with the loss of pollinating insects, have undoubtedly influenced extinction rates.
Between control and complexity: opportunities and challenges for marine mesocosms . Sagarin, R.D., Adams, J., Blanchette, C.A., Brusca, R.C., Chorover, J., Cole, J.E., Micheli, F., Munguia-Vega, A., Rochman, C.M., Bonine, K., van Haren, J. and Troch, P.A. (2016): Frontiers in Ecology and the Environment 14(7): 389–396.
Does the Production of Isoprene Affect the Productivity of Poplars? . McFarland, E.J., Parra, E.A., Barron-Gafford, G., Minor, R.L., and Heard M. (2015): STAR (STEM Teacher and Researcher) Program Posters.
Precipitation pulse dynamics of carbon sequestration and efflux in highly weatherable soils . Barron-Gafford, G., Minor, R., Van Haren, J.L., Dontsova, K., Troch, P.A. (2013): Abstract EP13C-0879 presented at 2013 Fall Meeting, AGU, San Francisco, CA, 9-13 Dec.