Watershed threats

The single greatest threat to the native forest is the destruction caused by non-native, invasive animals and plants.  Nearly two-thirds of Maui’s original forests have already been lost and now more than ever is the time to stop the invasion of species into the remaining pristine areas of the forest.

UNGULATES

Pigs, goats, cattle and deer damage Hawaii’s native forests with their browsing, rooting and trampling.  Soil erosion is accelerated.  Native plants are destroyed and replaced with non-native weeds whose seeds are carried in the fur, feet and feces of browsing ungulates.  Native plant species such as maile and mamane are being replaced by banana poka and strawberry guava.  Many of the native plant species have significant cultural importance to our island’s residents and they are disappearing fast!

AVIAN DISEASE

What do mosquitoes and pigs have in common?  Avian malaria and avian pox.  Mosquitoes are carriers for these deadly diseases that have been responsible for the decimation of many native bird populations in lowland areas.  Feral pigs in the forest create muddy wallows and push down hapu’u ferns, eating out the starchy middle, creating a trough.  Rainwater collects in the wallows and troughs which serves as excellent breeding ground for disease bearing mosquitoes.  Because of avian diseases, many native birds have been “pushed back”, forced to take refuge in higher elevations, away from mosquitoes.  That is why we rarely see Apapane, Amakihi, or I'iwi in elevations lower than 4000 feet.

INVASIVE PLANTS

Miconia is a fast-growing weedy tree from South America that is now invading Hawai’i.  It has large, dark green leaves with purple undersides.  It looks like a bush when young, but can grow up to 50 feet tall.  Because it is so large, and grows so quickly, Miconia kills other plants by shading them out, preventing sufficient sunlight from reaching the understory.  A single miconia plant produces millions of tiny seeds that spread quickly.  It has already destroyed 70% of the forest growth in Tahiti.  You can help protect Maui’s ecosystem by informing Maui Invasive Species Committee (MISC) if you think you’ve found Miconia, call 573-MISC (6472)

Rats are a big problem on the islands. They climb trees and prey on bird eggs and even adults!

Mongooses (not mongeese!) were introduced to the islands to control the rats. Only one problem: Rats are nocturnal (active during the night) and mongooses are diurnal (active during the day). So, instead of preying on rats, mongoose will eat birds, their chicks and their eggs.

for more information, email us at info@eastmauiwatershed.org