Assessing the conservation value of a human-dominated island landscape: Plant diversity in Hawaii

Abstract

The conversion of native habitats to pasture and other working lands, unbuilt lands modified by humans for production, is one of the greatest threats to biodiversity. While some human-dominated landscapes on continents support relatively high native biodiversity, this capacity is little studied in oceanic island systems characterized by high endemism and vulnerability to invasion. Using Hawaii as a case study, we assessed the conservation value of working landscapes on an oceanic island by surveying native and non-native plant diversity in mature native forest and in the three dominant land covers/ uses to which it has been converted: native, Acacia koa timber plantations, wooded pasture, and open pasture. As expected, native plant diversity (richness and abundance) was significantly higher and non-native abundance significantly lower in mature native forests than any other site type. A. koa plantations and wooded pasture supported four and three times greater, respectively, species richness of native understory plants than open pasture. Also, A. koa plantations and wooded pasture supported similar species communities with about 75% species in common. Conservation and restoration of mature native forest in Hawaii is essential for the protection of native, rare species and limiting the spread of nonnative species. A. koa plantations and wooded pasture, however, may help harmonize production and conservation by supporting livelihoods, more biodiversity than open pasture, and some connectivity between native forest remnants important for sustaining landscape-level conservation value into the future.

Does plantation forestry restore biodiversity or create green deserts? A synthesis of the effects of land-use transitions on plant species richness

“…As plantations become an increasingly ubiquitous land use, intense debate surrounds the extent to which these anthropogenic forests protect or degrade biodiversity (Norton 1998;Brockerhoff et al 2008). Improved understanding of how plantations and other ''working landscapes'' affect biodiversity and other ecosystem services is critical to forming socially and ecologically sustainable land-use policies (Goldman et al 2008).…”

“…While this will not necessarily reflect biodiversity of other taxa, understory vegetation is considered to be a good predictor of faunal diversity (Humphrey et al 1999). Moreover, plants are the basis of the food chain and contribute to important ecosystem services including climate regulation, water purification, and pollination (Daily 1997;Goldman et al 2008). As such, an evaluation of plantations and plant diversity provides valuable information on the effects on vegetation with implications for wider ecosystem services and the faunal diversity they support.…”

Forest biodiversity assessment in Peruvian Andean Montane cloud forest

“…In Hawaiian montane forests, fallen logs provide the most common germination sites for woody species; between 50 and 70% of natural regeneration occurs on decaying logs in these forests (Goldman et al 2008). These logs also create a diversity of microhabitats for a wide variety of organisms (Wilcke 2005).…”

Coral larvae spreading based on oceanographic condition in Biawak Islands, West Java, Indonesia

“…Improved understanding of how reforestations affect biodiversity and other ecosystem services is critical to forming socially and ecologically sustainable land-use policies (Goldman et al 2008).…”