It cannot be denied that hurricanes can negatively affect residents in their paths. But on a broader scale, ecosystems within their paths often evolved because of this influence and can benefit from a hurricane’s periodic lashing. But for humans, hurricanes often exact a terrible price on life and property.
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Hurricanes also have positive effects such as:
- Bacteria and red tide breakup
- Help to balance global heat
- Replenishment of barrier islands
- Replenish inland plant life
- Spread plant seeds
Hurricanes may destroy organisms, but they may also promote their spread. Seeds borne on their ferocious winds may be sown far from their sources, facilitating the dispersal of many plant species. In South Florida, tropical hardwood hammocks -- patches of rich jungle scattered amid expanses of sawgrass glades and pine forests – more than likely had help from hurricanes.
Most of the shrubs and trees composing these shadowy, wild pockets composed of West Indian mahoganies, gumbo-limbo, strangler fig and others come from the Caribbean and the Central and South American tropics. While many of these seeds likely reached the toe of Florida via bird gullets or ocean currents, scientists speculate that hurricanes churning in from the Atlantic or Gulf of Mexico are also responsible.
Hurricanes deposit vast quantities of seafloor and estuary sediments as they muscle ashore, accumulations that provide footholds for coastal vegetation communities. The storms may ravage existing mangrove swamps, but also mound-up banks of sand, mud or marl – soil consisting of limestone and clay – in which seedlings or dislodged mature trees establish new stands. In hyper-saline lagoons, such as the Laguna Madre complex of southeastern Texas and adjoining Mexico, hurricanes periodically flush the salty waterways, providing notable contributions of more diluted seawater and freshwater rain and runoff.
A hurricane that flattens a hardwood hammock or a deciduous forest may seem an agent of destruction, but such disturbances are a natural and necessary part of ecosystem function. The toppling or defoliation of mature canopy trees allows sunlight to reach the previously dark understory, permitting shade-intolerant species to proliferate. These may experience years of dominance until shade-tolerant trees create a canopy again. Such cycling of vegetation communities is called succession, and it promotes biodiversity by giving more species the chance to occupy a given ecosystem and maintaining landscape mosaics of greater complexity.
The often-torrential rainfall associated with hurricanes can be a double-edged sword. Flooding is commonplace in the wake of a storm, threatening human life and property. But the deluges of passing hurricanes and their weakening, but still wet remnants, can also be a boon for areas experiencing the late-summer droughts that sometimes coincide with tropical-cyclone season. Storm precipitation may benefit parched crops in a severely dry stretch of the growing season or help douse long-raging wildfires.