Habitat Loss and Degradation
Large-scale Loss of HabitatHabitat Loss
Before human arrival, the Hawaiian Islands were primarily covered in diverse forests and ecosystems, home to unique plants and animals found nowhere else in the world. This is due to the isolation of the Hawaiian Islands. Organisms arrived in the Islands naturally, only some being able to survive the thousands of miles journey across the Pacific Ocean and then procreating to continue the journey of adaptation to the conditions of the Islands. This adaptation and evolution occurred over millions of years prior to humans with species becoming endemic to certain islands, valleys, and mountain tops.
On Maui, flightless birds like ducks, geese, ibis, and rails thrived in the understory, while numerous songbirds filled the treetops. Once humans arrived, some species were hunted to extinction while others, especially those who lived in the lowlands, lost their habitat to agriculture and human development. Later, European settlers introduced domestic ungulates (hoofed mammals) and expanded ranching and logging, further destroying native habitats. Today, only 40% of Hawai‘i’s vegetation is native, and less than 10% of mesic forest and 3% of dry forest remains. Protecting these fragile ecosystems requires ongoing efforts to remove invasive species and preserve what’s left.
Invasive plant species
Invasive plants have severely degraded native Hawaiian forests. Introduced and invasive plant species have contributed to habitat degradation and the loss of suitable native forest bird habitat across Hawai’i. Invasive species are non-native (plant, animal, or microbe) transported by humans to a location outside its native range and whose introduction does or is likely to cause economic, environmental, and/or human health harm. These non-native species outcompete native plants and reduce biodiversity. They consume more water, lowering forest and watershed health, and most native birds don’t recognize them as a food source. Organizations like the Maui Invasive Species Committee work to prevent their spread.
Because invasive plants are often very difficult to control once they have entered an area, prevention of new introductions is crucial. MFBRP carefully cleans gear to prevent introducing new weeds and uses GPS to track and remove invasive plants, collaborating with partners for intensive management efforts. In our field sites, we are on the lookout for Gorse, Kahili Ginger, Blackberry, Eucalyptus, non-native grasses, Miconia, Australian tree ferns, and more.
Another possible introduced group of species that could be impacting native ecosystems, competing with native birds, and spreading non-native diseases are introduced bird species.
Rapid ʻŌhiʻa Death (ROD) is a fungal disease killing native ʻōhiʻa trees. It was first detected on Hawai‘i Island in 2015 and later on Kaua‘i. This disease has already decimated hundreds of thousands of trees, and preventing its spread statewide is crucial.
You can help by learning to identify invasive species and prevent their spread. This includes cleaning your hiking and camping gear and avoiding introducing new species. Report pests when spotted.
Ungulates
Hoofed animals introduced by early European explorers, like goats, pigs, and cattle, have wreaked havoc on native forests. By the 1800s, ranching and feral populations had destroyed vast areas of mesic forest. Today, wild descendants of these animals still damage ecosystems, with herds of goats and over 50,000 axis deer continuing to spread into higher elevations.
Efforts to control these populations began in the mid-1900s, and hundreds of miles of fencing have since been installed to protect native forests. Restoration efforts continue, and upcoming projects aim to fence remaining forest areas, allowing ecosystems to recover from centuries of damage.
The impacts from feral ungulates include eating of understory species and the prevention of regeneration of the forest, the spread of non-native and potentially invasive species, and creating habitat for non-native disease-spreading mosquitoes.