The role of sub-surface fissures on the establishment of an
invasive woody shrub (Prosopis glandulosa) in grasslands.
JURENA, P.N.* and S.ARCHER Texas A&M University, College
Station, TX 77843-2126 1 We tested the hypothesis that
establishment of woody plants in grasslands underlain by
indurated limestone would be facilitated by `fissures' which
give tree/shrub tap roots preferential access to deep stores of
water and nutrients. Survival and growth of Prosopis glandulosa
seedlings was monitored along ten 5 m transects perpendicular to
known fissures. Soil depth along the transects ranged from 0 to
20 cm and decreased with increasing distance from the fissure.
Contrary to expectations, no seedlings emerged from seeds
planted directly over the fissure. Survival of Prosopis
seedlings emerging 5 m from the fissure was 2x greater than that
of seedlings emerging 1 m from the fissure. Survival
trajectories for all seedlings were similar and reached zero
within seven months of the initial planting. Seedlings farthest