![]() Feedbacks within an “ecogeomorphic” system are illustrated in the following three examples and summarized in a conceptual model ( Figure 2). Legacies in drylands occur across disciplines and scales, and are a function of three variables: (1) the magnitude of the historical phenomenon, (2) the time elapsed since its occurrence, and (3) the sensitivity of the ecological–soil–geomorphic system to change ( Rachal et al. Impacts also depend on the severity of the originating condition Such legacies may represent short-, medium-, or long-term effects 2009).Įcological legacies are the impacts of past conditions on current landscapes For example, the 13C/ 12C ratio in soil organic matter in a shrubland may “remember” a former grassland, but its memory will fade more quickly than the 13C/ 12C ratio in carbonate minerals of that same soil ( Monger et al. Such studies have shown that some properties have better “memories” than others. The “environment → processes → properties” triad can also be investigated in reverse to understand paleoenvironments (eg Targulian and Goryachkin 2004). Examples include rainfall → photosynthesis →net primary production (in ecology) vegetative cover → organic matter accumulation → pH (in soil science) and mountain building → erosion → landforms (in geomorphology). In drylands, ecologists, soil scientists, and geo-morphologists have shown that environmental conditions govern processes that, in turn, generate properties. Scientists from numerous disciplines also acknowledge the role of legacies in the following triad: “environment → processes → properties” (eg Birkeland 1999 Turner et al. Though long abandoned, the ancient structures still capture runoff water as reflected by lush seasonal vegetation. Ruins associated with a Roman–Byzantine-era farm near the ancient city of Shivta in the Negev Desert, an example of water harvesting techniques that have created a legacy effect on the desert landscape.
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