Casuarina equisetifolia (tree)

Ecology Distribution Management Info Impact Info References and Links Contacts

General Impact Swearingen (1997) states that C. equisetifolia is fast-growing (1.5 to 3 metres per year), produces dense shade and a thick blanket of leaves and hard, pointed fruits, that completely cover the ground beneath it. Dense thickets displace native dune and beach vegetation, including mangroves and many other resident, beach-adapted species. Once established, it radically alters the light, temperature, and soil chemistry regimes of beach habitats as it outcompetes and displaces native plant species and destroys habitat for native insects and other wildlife. Chemicals in its leaves may inhibit the growth of other plants underneath it. The ground below the tree becomes ecologically sterile, reducing the food value for native wildlife. Unlike native shrubbery, the thick, shallow roots make it much more susceptible to blow-over during high wind events, leading to increased beach and dune erosion and interference with the nesting activities of sea turtles and American crocodiles. Elfers (1988) reports that Casuarina also poses a problem to humans because it is a source of respiratory irritation. Its pollen can cause allergic reactions symptomised by eye irritation, runny-nose, and hoarseness or sore throat.          Location Specific Impacts: Bermuda   Physical disturbance: Casuarina equisetifolia promotes coastal erosion. It is easily uprooted during hurricanes causing damage to other trees and plants (Glasspool, 2003 in Varnham, 2006). Reduction in native biodiversity: Casuarina equisetifolia overshades native costal plants, its dense mat of fallen needles smothers native vegetation and is unlikely support full native invertebrate community. Threat to endangered species: Casuarina equisetifolia affects coastal tropic bird (Phaethon lepturus) nest sites (Glasspool, 2003 in Varnham, 2006). Anegada Is. (British Virgin Islands)   Reduction in native biodiversity: There is concern that casuarina if allowed to spread could become the dominant forest cover, suppressing native understory species and possible causing the extinction of iguanas and many native birds (Veitch, 1998 in Varnham, 2006). Cayman Brac (Cayman Islands)   Competition: Casuarina aggresively colonizes sandy beaches where it forms monocultures with deap leaf litter killing native vegetation. Physical disturbance: Casuarina's shallow root system leaves trees prone to uprooting in storms, accelerating coastal erosion. Grand Cayman (Cayman Islands)   Competition: Casuarina aggresively colonizes sandy beaches where it forms monocultures with deap leaf litter killing native vegetation. Physical disturbance: Casuarina's shallow root system leaves trees prone to uprooting in storms, accelerating coastal erosion. Little Cayman (Cayman Islands)   Competition: Casuarina aggresively colonizes sandy beaches where it forms monocultures with deap leaf litter killing native vegetation. Physical disturbance: Casuarina's shallow root system leaves trees prone to uprooting in storms, accelerating coastal erosion. Reunion (La Réunion)     Modification of successional patterns: Casuarina equisetifolia increases the concentration of nitrogen in volcanic soils and prevents vegetational succession (Mac Donald et al.., 1991).