Name:
Waltheria indica / Heteropogon contortus Lowland Dry Shrubland & Grassland Group
Reference:
NatureServe Biotics 2019
Description:
This lowland dry grassland and shrubland group is characterized by either a grass layer typically dominated by <i>Heteropogon contortus</i>, or an open to closed short (<2-m tall) shrub layer. The shrub layer is dominated by <i>Artemisia australis, Psydrax odorata, Dodonaea viscosa, Bidens</i> spp., <i>Sesbania tomentosa, Waltheria indica</i>, or <i>Wikstroemia</i> spp. The grasslands may include other native grasses such as <i>Eragrostis variabilis, Fimbristylis</i> spp., <i>Lepturus repens</i>, or <i>Sporobolus virginicus</i> which are more common near coasts where these stands grade into coastal strand. Scattered shrubs such as <i>Dodonaea viscosa, Sida fallax</i>, and <i>Waltheria indica</i> are often present and become more abundant with absence of fire. The grasslands were once fairly widespread and were maintained and expanded by regular burning by ancient Hawaiians. The shrublands often have other native shrubs present such as <i>Argemone glauca, Canavalia</i> spp., <i>Chamaesyce</i> spp., <i>Cassytha filiformis, Ipomoea</i> spp., <i>Lipochaeta</i> spp., <i>Nototrichium</i> spp., <i>Osteomeles anthyllidifolia, Peperomia tetraphylla, Peperomia blanda var. floribunda, Santalum ellipticum, Senna gaudichaudii, Sicyos</i> spp., <i>Myoporum sandwicense, Sida fallax</i>, and <i>Styphelia tameiameiae</i>. Indicators species of this group include <i>Abutilon</i> spp., <i>Achyranthes</i> spp., <i>Capparis sandwichiana, Gossypium</i> spp., <i>Heteropogon contortus, Hibiscus brackenridgei, Plectranthus parviflorus, Portulaca</i> spp., and <i>Waltheria</i> spp. Dry species may include ferns <i>Doryopteris</i> and <i>Pellaea</i> and grasses <i>Panicum</i> spp. Exotic species such as <i>Pennisetum setaceum</i> are often present in disturbed stands, but do not dominate. The density and height of shrubs may be reduced by recent fire or increased with increased moisture, for example when near riparian areas. Lowland dry shrublands are relatively intolerant to grazing pressure and fire and are replaced by alien-dominated communities when subjected to these disturbances. Many dry grasslands have been replaced by exotic grass species or converted to exotic shrublands. This group was widespread historically and occurred on leeward sides of all the main islands and on many of the smaller dry islands, although the shrublands are not reported from Ni`ihau and Kaho`olawe. It is less common now and remaining stands are mostly disturbed by invasive species or altered fire regime. Elevation ranges up to 1000 m and grades into dry strand along the coasts. High-elevation stands transition to montane shrublands near 1000 m elevation. These shrublands occur on open gentle slopes to steep ridges of dissected slopes. Climate is tropical with summers hot and dry. Annual precipitation is mostly restricted to the winter months, and ranges from 500 to 1750 mm for shrublands and most grasslands, but grasslands also occur in drier areas (down to 100 mm annual precipitation). Substrates are variable. Soils range from silty loams to relatively unweathered pâhoehoe lava. This group also includes coastal dry grasslands that occur beyond the immediate coastal effects of the sea with wind, salt spray and salinity.
Accession Code:
urn:lsid:vegbank.org:commConcept:40145-{22DB2A3D-DECC-4BF1-9A8C-40C67C6BE4F2}
Plot-observations of this Community Concept:
0
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