View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by ScholarSpace at University of Hawai'i at Manoa CProceedingsonservation of relevan the hawaiianCe of inse entomologicalCt monitoring s ociety (2013) 45:149–166 149 The Importance of Insect Monitoring to Conservation Actions in Hawaii Matthew J. Medeiros1, 2*, Jesse A. Eiben3, William P. Haines4, Raina L. Kaholoaa5, Cynthia B.A. King6, Paul D. Krushelnycky4, Karl N. Magnacca7, Daniel Rubinoff4, Forest Starr8, and Kim Starr8 1Urban School of San Francisco, San Francisco, CA 94117. 2University of California, Department of Integrative Biology, Berkeley, CA 94720. 3University of Hawaii at Hilo, College of Agriculture, Forestry and Natural Resource Management, Hilo, HI 96720. 4University of Hawaii at Manoa, Dept. of Plant and Environmental Protection Sciences, Honolulu, HI 96822. 5Haleakala National Park, Makawao, HI 96768. 6Hawaii Division of Forestry and Wildlife Native Invertebrate Program, 1151 Punchbowl Street, Room 325, Honolulu, Hawaii 96813. 7Oahu Army Natural Resources Program, PCSU, Schofield Barracks, HI 96857. 8Starr Environmental, Makawao, HI 96768. *Author to whom correspondence should be addressed: [email protected] Abstract. Endemic insect species make up the overwhelming majority of Hawaii’s native fauna, and play many important ecological roles. Despite this, insects receive low levels of conservation funding, likely due to their small size, fluctuating popula- tion sizes, and lack of baseline data necessary to determine if they are threatened with extinction. To determine which insects are at risk, how insect populations fluctuate in natural areas, and which management actions are most beneficial to Hawaiian ecosystems, we propose that insects be monitored whenever possible. Insect monitoring should be broad, generating community-based metrics such as species richness, rather that focusing on individual species. Resultant data should be entered into a stable, central database. Rather than individual insect species being the explicit target of conservation, we emphasize that measures of insect diversity can provide an assessment of restoration efforts, and serve as a metric for prioritizing areas for conservation. We provide lists of additional recommenda- tions for land managers and research entomologists who wish to assist with insect conservation efforts. Key words: database, endemic species, indicator species, invasive species, moni- toring, population trends I. Hawaiian insect diversity and terrestrial biodiversity. In terms of sheer the importance of insect number of species, insects are the major conservation components of biodiversity in virtually Most biologists would agree that a any terrestrial ecosystem, and this is es- primary global goal of conservation is pecially true in Hawaii, where the current the protection of biodiversity, whether it native terrestrial vertebrate fauna consists is measured in terms of species (Myers et only of birds and a single species of bat. al. 2000), evolutionary lineages (Williams At last count, Hawaii had nearly 5500 et al. 1991), or ecological diversity (Soule described native insect species, nearly all et al. 2003). By any of these measures, in- of these endemic (Nishida 2002), and this sects account for the majority of Hawaiian number grows steadily as new species are 150 medeiros et al. described. In fact, insects comprise 53% of tion rates as high as, or higher than other all described endemic life forms in Hawaii groups (McKinney 1999). Moreover, it is and 70% of all endemic animals, includ- possible that the continued decline and ex- ing both terrestrial and marine organisms tinction of plants and birds that are already (Figure 1; Eldredge 2000). Invertebrates favored with conservation resources (e.g., as a whole, including other arthropods and the endemic birds poouli, Melamprosops mollusks, account for 82% of all endemic phaeosoma; alala, Corvus hawaiiensis; life forms and 97% of endemic animals palila, Loxioides bailleui) may be due (Eldredge 2000). to the disintegration of ecosystems more Because insects are such an important broadly, and the decline of native insects, component of Hawaiian ecosystems in specifically. Thus, ignoring the plight of terms of species richness, it stands to native insects may contribute to the disap- reason that they fill many ecological pearance of those more ‘charismatic’ ele- niches and provide important ecological ments of biodiversity. Ultimately, focusing services. Although little is known about nearly all conservation resources on plants specific plant-pollinator relationships in and birds may not serve the long term Hawaii, insects are certainly the primary interests of those taxa, if the insects on pollinators of native plants. Based on floral which they directly or indirectly depend morphology, 67% of endemic flowering are left to disappear. plants are thought to be insect pollinated, compared to only 19% bird pollinated, II. Challenges to insect and 14% wind-pollinated (Sakai et al. conservation 2002). Insects are also important parts Despite insects being such a crucial of food webs, being the primary native component of Hawaiian biodiversity, ver- consumers of plants (especially in the tebrates and plants continue to receive the absence of herbivorous mammals), and lion’s share of conservation attention and important decomposers of organic matter. funding. To make matters worse for insect Insects are critical sources of protein for conservation efforts, Hawaii’s share of all native forest birds, especially when nation-wide conservation funding is vastly nesting and raising young (Mountain- underrepresented (Leonard 2008). Lack of spring 1987, Ralph and Fancy 1994), and funds for insect conservation is likely due the relationships between birds and their to a combination of factors that complicate insect prey can be highly specific (Banko such efforts, including practical problems et al. 2002). The Hawaiian hoary bat or faced by land managers, as well as nega- ōpeapea (Lasiurus cinereus semotus), an tive or indifferent public attitudes towards endangered species, feeds exclusively on insects. In general, the United States lags insects and other arthropods (Whitaker in its efforts to conserve invertebrates, and Tomich 1983, Jacobs 1999, Fullard with disproportionately poor representa- 2001). Of course, insects also serve as food tion of arthropods on the endangered spe- for each other, with extremely complex cies list (one arthropod per 16 vertebrates relationships among native herbivorous and plants). Hawaii, which lacks most of insects and their predators and parasitoids the vertebrates that garner the attention (Henneman and Memmott 2001). of continental conservationists but has Yet, this high diversity among insects a much higher percentage of endemic is not indicative of the security of their insects, might be expected to do better persistence, and insect species in Hawaii than the national average. Regrettably, have almost certainly suffered extinc- Hawaii is doing worse: a lower percentage Conservation relevanCe of inseCt monitoring 151 Figure 1. Insect species account for 70% of Hawaii’s total number of endemic animal species. of the Hawaiian arthropod fauna is listed or spend all or most of their lives under as endangered than at the national level rocks, high in the tree canopy, or buried (one arthropod for every 19 vertebrates in moss or leaf litter. This means that as- and plants), and current practice largely sessments of population status or extinc- ignores the conservation of insects. For tion of individual species require a highly example, the Kauai green sphinx (Tinos- focused search effort. Additionally, the toma smaragditis) has been collected less adult life stages of many insects are able than 20 times since its discovery. Despite to fly and are therefore highly dispersive, very little being known about its life his- making it extremely difficult to follow tory, no studies are currently being funded individuals over time. Tracking insects to learn more about it, even though this using GPS or radio technology is currently moth is the sole species of an endemic impossible for all but the largest insects, genus. Only a few Hawaiian insects are although marking with paints or tags is now federally listed, and these represent feasible for some species (see McGeoch et a small fraction of the species at risk and al. 2011 for an introduction to the broader an insignificant proportion of Hawaii’s literature regarding insect monitoring). overall insect diversity. Compared to vertebrates and many Why does this lack of emphasis on in- plants, insects usually have relatively short sect conservation exist in the first place? lifespans, rapid generation times and often Perhaps the most obvious difficulty re- high reproductive output, meaning that garding insect conservation is that most populations can fluctuate greatly, both insects are very small and cryptic, often temporally and spatially. Some native noticed only after careful observation of insects exhibit “boom or bust” population an ecosystem. Many insects are nocturnal, dynamics, persisting at unnoticeable levels 152 medeiros et al. most of the time, but then experiencing of its documented history—which includes occasional population explosions when the vast majority of Hawaiian insects, par- they are common, or even considered ticularly in highly-diverse radiations—it pests. For most species, the underlying is especially difficult to ascertain when causes