The hidden oases: unveiling trophic dynamics in Namib’s fog plant ecosystem
Fog Collecting Grass Stipagrostis sabulicola
In the southwestern part of the African continent, along the Atlantic coast of Namibia, lies the Namib Desert. This vast desert extends into southern Angola and northern South Africa. The Namib Desert is an extremely arid desert with minimal rainfall due to its geographical features. Consequently, fog, which forms when moisture evaporates from the Atlantic Ocean and is carried inland by the wind, serves as the primary source of moisture. As a result, plant species that effectively utilize this fog have evolved. One such plant is the grass Stipagrostis sabulicola. S. sabulicola has highly hygroscopic leaves and stems that can efficiently collect water droplets from the fog. Additionally, the grooves on its leaves and stems act like rails, guiding the water droplets to the growth points and roots. Thanks to this structural evolution, S. sabulicola can thrive in areas where rain is scarce, and fog is prevalent. Although the mechanism of fog collection has been analyzed before, it has now been discovered that this fog collection significantly impacts not just the plant itself but also the surrounding ecosystem.
Above Ground: A Habitat and Carbon Source for Invertebrates and Microorganisms
S. sabulicola grows in clusters scattered across the desert. The size of these clusters varies, starting as small patches of a few dozen centimeters and expanding to several meters as S. sabulicola collects fog and proliferates. By obtaining moisture and performing photosynthesis, it synthesizes organic matter in barren lands. The living plant itself hosts endophytic fungi, forming a microbial ecosystem. Additionally, as the plant spreads horizontally through underground stems, some of its stems and leaves wither and become food for microorganisms and insects. Thus, as S. sabulicola expands its growing area, it provides a carbon source and enlarges the habitat for other organisms. S. sabulicola is truly precious.
Underground: A Cradle for Life
S. sabulicola also supports the growth of other organisms underground. The collected fog forms water droplets, which are supplied to the underground part, moistening the surrounding soil. Additionally, carbon synthesized through photosynthesis is used to produce organic matter, which is released around the roots. As a result, an environment conducive to the growth of soil microorganisms is established, forming a rhizosphere microbial flora. As microorganisms increase, nematodes and other organisms that feed on them can grow, and their waste products function as fertilizer for the plants. Ultimately, even though it is for its own benefit, S. sabulicola supports biodiversity underground and is precious.
Fog Plants Supporting Desert Biodiversity
Despite the harsh environment with little rainfall, S. sabulicola has created a biodiversity similar to that found in fertile lands. This is truly an oasis formed by fog. Although these oases are small, their gradual growth through mutual influence reflects the resilience of organisms that never give up on living, no matter where they are.
Compared to the desert, even the cracks in asphalt might seem like paradise. For plants, there may be no place where they cannot grow.
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