The Ecology of Tijuana Estuary, California: An Estuarine Profile

Figure 30. During winter (above) the salt pannes accumulate water from high spring tides and rainfall: during
summer they dry and are covered by a white salt crust. Algae and ditch grass (Ruppia maritima) grow during the
aquatic phase: pintails and other aquatic birds feed and rest there. In summer, abundant burrows of a diverse insect
carnmunity are present. Mctntire coileclion, ~opyright f 986 by Zedler.
"middens." The density of middens reaches belt at about the high tlde line. The beetles appear
50Q/m2; the tunnels beneath them are about 20 crn to prefer soil dampened by t~dal inundation but not
in depth Densities af beetles were highest in covered by standing water A typical biweekly
March 1984, when 8 adults and 22 juveniles were fluctuat~on of midden dens~t~es occurs with the
recorded per 1,650 cm3 core Reproduct~on high summer t~des: as a high tide recedes, midden
occurred In the spring with eggs attached to the mounds appear as the beetles begin to burrow,
s~des of burrows Dy means of a clear, threabiike more densely at the region where the soils have
material
begun to dry and iess densely at the water's edge;
as the so11 dries, the middens accumulate as
tntertrdal elevation ts the most important excavation activities continue; then, an ensuing
physical variable that characterizes rove beette high tide erases the surface m~ddens, and the
d$strrbut~on patterns They are densest In a narrow pattern IS repeated. It IS not known what happens