Today, restoration of resilient native ecosystems that minimize extinction risk and maximize ecosystem services has never been more important. Success stories, such as that of Hakalau Forest National Wildlife Refuge and papers in this special feature, demonstrate the value in large-scale efforts. However, the number of decision makers involved and siloed agencies responsible for land and nearshore coastal management, incomplete or contradictory knowledge regarding community and ecosystem dynamics, the large costs associated with complete restoration, and the interconnectedness of restoration decisions with social, cultural, policy, and economic dimensions, clearly classify the process of attempting large-scale restoration of degraded systems as a wicked problem. We wish to outline three focal areas that specifically address each of the challenges associated with wicked problems and that may improve the likelihood of achieving restoration goals. First, managers and decision makers must identify clear objectives that will guide decisions regarding restoration actions. Second, research funded through conservation initiatives should be aimed at reducing uncertainty in ways that increase the probability of choosing a set of management actions likely to have a desirable outcome. Finally, we need innovative solutions that borrow from industries that have already discovered economy of scale, as well as partnerships among those in the fields of social science, economics, policy, and the natural sciences. The collection of articles in this special feature illustrate how objective-driven studies, high-value research in areas of uncertainty, and collaborations among economists, cultural practitioners, and scientists can move us toward the identification of optimal solutions. Ultimately, we wish to restore systems in ways that reduce conservation reliance and result in resilient, self-sustaining native ecosystems.

Resource managers increasingly seek to implement cost-effective watershed restoration plans for multiple ecosystem service benefits. Using locally adapted ecosystem service tools and historical management costs, we quantified spatially explicit management costs and benefits (in terms of groundwater recharge and landscape flammability) to assist a state agency in evaluating cobenefits for a predefined restoration scenario (focused on biodiversity benefits) and to prioritize an expanded restoration scenario in the state-managed Pu‘u Wa‘awa‘a watershed ( Hawai‘i) now and under the Representative Concentration Pathway (RCP) 8.5 midcentury climate scenario. Restoring all available areas increases recharge by ∼1.74 million m³/yr (5% of recharge over the entire watershed) under the current climate and does not meaningfully change recharge under RCP 8.5 midcentury, whereas climate change decreases recharge by ∼50%. For landscape flammability, climate change increases the median and maximum probability of fire occurrence across all land use scenarios, and full restoration results in the greatest reduction in landscape flammability under both current and RCP 8.5 midcentury climate scenarios. We demonstrate that location and type of forest restoration influence overall cost-effectiveness of restoration, providing insights for landscape planning for ecosystem services under a limited budget. Across all scenarios, capturing potential benefits at low elevations requires greater expenditures ($13,161/ ha) than at high elevations ($5,501/ ha) due mainly to the substantial costs of removing Pennisetum setaceum (fountain grass), the dominant land cover below 1,000 m. If management focuses on groundwater recharge only, the most cost-effective areas occur at high elevations (>1,000 m), with ample fog interception, although recharge benefits decline across the landscape under RCP 8.5 midcentury. Focusing instead on cost-effective landscape flammability reduction as the primary management objective shifts emphasis toward dry low-elevation areas under the current climate. However, under the RCP 8.5 midcentury scenario, the most cost-effective areas for flammability management shift toward higher elevations with greater potential overlap with recharge benefits.

European mouflon (Ovis gmelini musimon), the world's smallest wild sheep, have proliferated and degraded fragile native ecosystems in the Hawaiian Islands through browsing, bark stripping, and trampling, including native forests within Hawai‘i Volcanoes National Park (HAVO). HAVO resource managers initiated ungulate control efforts in the 469 km² Kahuku Unit after it was acquired in 2003. We tracked control effort and used aerial surveys in a 64.7 km² area from 2004 to 2017 and more intensive ground surveys and camera-trap monitoring to detect the last remaining animals within a 25.9 km² subunit after it was enclosed by fence in 2012. Aerial shooting yielded the most removals per unit effort (3.2 animals/ hour), resulting in 261 animals. However, ground-based methods yielded 4,607 removals overall, 3,038 of which resulted from assistance of volunteers. Ground shooting with dogs, intensive aerial shooting, ground sweeps, and forward-looking infrared (FLIR)-assisted shooting were necessary to find and remove the last remaining mouflon. The Judas technique, baiting, and trapping were not successful in attracting or detecting small numbers of remaining individuals. Effort expended to remove each mouflon increased nearly 15-fold during the last 3 yr of eradication effort from 2013 to 2016. Complementary active and passive monitoring techniques allowed us to track the effectiveness of control effort and reveal locations of small groups to staff. The effort and variety of methods required to eradicate mouflon from an enclosed unit of moderate size illustrates the difficulty of scaling up to entire populations of wild ungulates from unenclosed areas.

Human activity has altered nearly every landscape on earth, and ecological restoration to repair degraded ecosystems has become a conservation necessity. Hawai‘i is a microcosm for intense landscape change, where levels of native biodiversity and threats to it are among the highest in the world, and where Kānaka Maoli (Hawai‘i's indigenous people), who stewarded these lands for a millennium, currently face massive inequalities. Consequently, biocultural restoration has emerged as a method to reciprocally restore ecological and cultural integrity and is especially applicable in Hawai‘i's sizeable invasivedominated areas. Since Kānaka Maoli are an inseparable part of every land and seascape in Hawai‘i, any ecological restoration project has the potential to use a biocultural restoration approach. However, most restoration approaches are purely ecological, and for many conservation practitioners a sociocultural understanding of the landscape can seem inaccessible. In this article, we discuss the value of a historical ecology approach (understanding the interaction between people and landscapes over time) for successful restoration and management of biocultural landscapes in Hawai‘i. We use a case study in Kahalu‘u, Kona, to outline historical ecology methods and available resources in Hawai‘i, including written documents, maps, imagery, archaeological studies, and interviews, and discuss applications of this approach on-the-ground. Potential benefits of employing this approach include expanding knowledge of reference conditions, understanding practices contributing to landscape function over space and time, and building meaningful relationships to engaging community around a site. We argue that a historical ecology approach is readily adoptable into ecological restoration in Hawai‘i, especially in its human-dominated landscapes.

Policy makers and resource managers in Hawai‘i often look to the ancient Hawaiian system of resource management, known as the ahupua‘a system, as a holistic and sustainable mountains-to-sea model for restoration of social-ecological system health and function. Many components of this ancient system, such as agriculture, aquaculture, and nearshore fishery management, have been documented, studied, and revived in the name of both sustainability and perpetuation of Hawai‘i's indigenous culture. One relatively glaring hole in the context of our understanding of this ancient system is management of forest resources on a system (i.e., large-scale plant community) level. Five terms for identified and managed social-ecological zones, wao kānaka, wao lā‘au, wao nāhele, wao kele, and wao akua, were used to delineate GIS layers in the model ahupua‘a of Hā‘ena. These were then extrapolated across the entire island of Kaua‘i. The resulting map indicates that not all ahupua‘a on Kaua‘i had all five social-ecological zones, which gives valuable insight into how upland regions of the various ahupua‘a may have been managed in the ali‘i era. This research has implications for contemporary approaches to large-scale biocultural conservation initiatives and other resource management plans that aim toward having broader community support for such efforts. Analysis shows that broad overlap between the ancient system and contemporary management zones exists, which implies that it may be feasible to adapt this ancient approach in the bureaucratic system of the contemporary era.

Nonnative, invasive grasses displace native plant communities and challenge ecological restoration globally. Ecological monitoring of restoration is typically short term and rarely reassessed to determine if initial findings are indicative of multiyear outcomes, and economic costs of restoration are seldom quantified. To address these knowledge gaps, we resampled a restoration experiment in an invasive Megathyrsus maximus—dominated ecosystem in Hawai'i to compare success of restoration treatments at 8 and 36 months. We calculated cost to establish and maintain (for 3 yr) experimental field trials (0.13 ha) and management-scale (1 ha and 10 ha) units, estimated 30-yr costs for management-scale units, and determined key drivers of costs. Survival of native outplant species did not differ between 8- (56%) and 36-month (51%) monitoring periods, and M. maximus cover was lower in restoration treatments than in control plots at both time periods. Cost to establish and maintain the experimental trial was $14,299 (Present Value at 2% annual discount rate, 2015 US$; $109,993 ha^-1). Scaling up restoration to 1 and 10 ha units produced economies of scale, with 3 yr costs declining with increasing area ($149,918 ha^-1 for 1 ha; $124,139 ha^-1 for 10 ha). Total Present Value to restore and maintain a 1 ha site for 30 yr ranged from $153,195 to $302,917 ha^-1, varying primarily based on labor and seedling costs. This study demonstrates that early restoration results can be indicative of longer-term results, establishment expenses drive long-term costs, and restoration efforts are most cost-effective when maintained over large spatial scales and long time periods. Importantly, this study allows other projects in the region to estimate restoration costs based on site-specific criteria.

Allochthonous nutrient flow from marine sources via seabirds to the terrestrial habitats where they nest can impact resident organisms and neighboring ecosystems. Seabird populations are decreasing both in Hawai‘i and globally, yet little is known about what is being lost from the ecosystems where they traditionally nested in large numbers. Given the marked decline in seabirds, we hypothesized that current sparsely populated seabird colonies in wet montane ecosystems of Hawai‘i contribute minimally to nutrient availability, but that this small contribution should still be reflected in vegetative uptake of soil N and in plant community composition. Soil nutrient availability on Kaua‘i was assessed using ion-exchange resin probes. Plant and soil uptake of marine-derived nitrogen was determined using δ¹⁵N values in soil and foliage of the two dominant species using a two-end member N isotope mass balance mixing model. To determine if the added nutrients impacted the plant community, we also compared canopy cover (total and by dominant species) and species richness between treatments. Soil in seabird areas had more available ammonium, but nitrate and total inorganic N did not differ between sites. The dominant canopy tree, Metrosideros polymorpha, derived 28% of foliar N from marine sources; this value was 15% for the dominant understory plant, Dicranopteris linearis. Plant species composition was not influenced by presence or absence of seabirds. Because N plays a large role in net primary productivity, use of marine-derived N by native plants under even limited seabird populations is likely important to functioning of these ecosystems.

Five butterfly species are reported from the Republic of the Marshall Islands: Badamia exclamationis, Danaus plexippus, Hypolimnas bolina, Junonia villida, and Lampides boeticus; the last requires corroboration. None is endemic to the Marshalls. All are widely distributed in the Pacific, and some well beyond. Hypolimnas bolina is the most common species in the Marshalls. It was recorded, often in large numbers, on all islands surveyed during the study reported here, and on all islands in the Marshalls where butterflies were previously recorded. Additional surveys of butterflies elsewhere in the Marshall Islands will doubtless result in many new locality records, but few additional species are likely to be added to the current list. Small island size together with limited habitat diversity, limited host-plant availability, and distance from potential source populations contribute to the paucity of species on these remote Pacific islands.

The wavy turban snail, Megastraea undosa (W. Wood), is an important fishery resource along the Mexican Pacific coast and a keystone species in subtropical rocky reefs. Its diet was determined from stomach contents of 125 specimens collected in three rocky reefs of the western coast of the Baja California Peninsula in July and November 2006 and March 2007. The snail consumed 20 taxa of seaweeds, 1 seagrass, and 11 taxa of invertebrates. The diet had significant variation depending on site and date. Main food items were Macrocystis pyrifera, Ecklonia arborea, and Corallina spp. Of secondary importance were red algae of the family Delesseriaceae and the genera Plocamium and Gelidium, the brown alga Stephanocystis osmundacea, the seagrasses Phyllospadix spp., the hydrozoan Dynamena, and the isopod Idotea. Analysis showed that the snail was a grazer with a mixed feeding strategy, feeding abundantly on kelp or coralline algae and also consuming many other resources, which was reflected in its variable trophic niche width with a Levins index ranging from 0.21 to 0.79.

Five species of dicroglossid frogs (Dicroglossidae) (n = 29) from Southeast Asia were examined for helminths: Limnonectes blythii, L. hascheanus, L. khasianus, L. kohchangae, and L. macrognathus. We found eight species of Nematoda, consisting of gravid individuals of Aplectana macintoshii, Cosmocerca ornata, Foleyellides malayensis, Icosiella innominata, Oswaldocruzia rohdei, Seuratascaris numidica, and larvae of Abbreviata sp. and Physalopteridae gen. sp. Dicroglossid frogs from Southeast Asia are infected by generalist helminths that infect other species of frogs. Twelve new host records are reported.