Ecological succession on abandoned roads in the Lake Mead National Recreation Area

John Daniel Bolling, University of Nevada, Las Vegas


With the intent of describing the processes controlling desert succession, I examined soil and vegetation dynamics along a chronosequence of abandoned roads in the Mojave Desert. Early successional shrubs dominated younger roads; the long-lived Larrea tridentata dominated older roads. Soils on roads were more compacted, and had higher bulk densities, lower available phosphorus and lower total nitrogen than adjacent control areas. No soil factors changed significantly with road age, perhaps due to the observed high spatial heterogeneity. Fertile island development was also slow to occur on roads. Roads created by surface vehicular traffic had higher levels of shrub cover, soil compaction, clay and organic matter, lower available nutrients, and more pronounced fertile island development than roads created by bulldozing. Studies of succession in deserts must take into account natural patterns of plant and soil heterogeneity and initial disturbance type as first steps to understanding recovery from disturbance.