Context. Accurate baseline data for wildlife populations are important to track trends of these populations over time and to identify threats to their long-term persistence. Aims. We aimed to assess the status and distribution of the little studied megapode (Megapodius laperouse laperouse) across the Mariana Islands. Methods. Using passive and call playback facilitated surveys in 2008 through 2010, we employed point-transect distance sampling to assess island-level and archipelago-wide status of this megapode. To assess conservation needs, we defined human presence as the current, recent, or intermittent occurrence of humans on islands. Key results. We recorded 657 megapode detections and estimated an archipelago level abundance of 11,542 individuals (95% CI: 5456-17,623) from 699 sampling points across 10 islands. Three islands supported 86% of the megapode population, but cumulatively comprise only 2% of the archipelago's land area. Conclusions. Micronesian Megapodes preferred native forest. Human presence and the availability of native forest may limit their abundance and distribution in the Mariana Islands. Although the probability of detecting megapodes was significantly greater on islands without high human presence, significantly more detections were recorded in forests with dense or closed understory on those islands that supported greater human populations. Implications. Given their status and confined distribution in the Mariana Islands, additional studies investigating megapode incubation sites and movement within and between islands would provide fundamental information on megapode ecology and enhance conservation efforts. Continued and expanded ungulate removal, predator control, and habitat restoration would further enhance the likelihood of megapode persistence in the archipelago.

In the face of unprecedented ecological changes, the conservation community needs strategies to recover species at risk of extinction. On the Island of Maui, we collaborated with species experts and managers to assist with climate-resilient recovery planning for 36 at-risk native plant species by identifying priority areas for the management of recovery populations. To do this, we developed a tailored spatial conservation prioritization (SCP) approach distinguished by its emphasis on transparency, flexibility, and expert (TFE) engagement. Our TFE SCP approach consisted of 2 iterative steps: first, the generation of multiple candidate conservation footprints (i.e., prioritization solutions) with a flexible greedy algorithm that reflects conservation practitioners' priorities and, second, the selection of an optimal conservation footprint based on the consideration of trade-offs in expert-agreed criteria among footprints. This process maximized buy-in by involving conservation practitioners and experts throughout, from setting goals to reviewing optimization data, defining optimization rules, and designating planning units meaningful to practitioners. We minimized the conservation footprint area necessary to meet recovery goals while incorporating species-specific measures of habitat suitability and climate resilience and retaining species-specific information for guiding recovery efforts. Our approach reduced the overall necessary conservation area by 36%, compared with selecting optimal recovery habitats for each species separately, and still identified high-quality habitat for individual species. Compared with prioritizr (an existing SCP tool), our approach identified a conservation area of equal size but with higher quality habitat. By integrating the strengths of existing techniques in a flexible and transparent design, our approach can address natural resource management constraints and provide outputs suitable for local recovery planning, consequently enhancing engagement and buy-in from conservation practitioners and experts. It demonstrates a step forward in making conservation planning more responsive to real-world complexities and helps reduce barriers to implementation for local conservation practitioners.

The Pacific sheath-tailed bat is an Old World bat in the family Emballonuridae, found in Polynesia, eastern Melanesia, and Micronesia. It is the only insectivorous bat in this area. These small (5.7 g) brown bats roost communally in caves and forage on insects in forests. There are four subspecies of Emballonura semicaudata: E.s. rotensis remains only on the island of Aguiguan in the Mariana Islands; E.s. semicaudata remains only in Fiji; E.s. palauensis in Palau; and E.s. sulcata in the Federated States of Micronesia. The species is threatened by predation by nonnative mammals; human and animal disturbance of roost caves or their wholesale destruction for mining or quarrying; foraging habitat loss due to deforestation and overgrazing by ungulates; and extreme climatic events such as tropical cyclones and typhoons. Priority actions include: establishment of international collaborations devoted to their conservation; formal protected status by governments; identification and protection of roost caves and their surrounding forest areas; genetic analysis to determine speciation and genetic diversity; and restoration of metapopulation equilibrium where it has been lost.

Summary Insular species, particularly birds, experience high levels of speciation and endemism. Similarly, island birds experience extreme levels of extinction. Based on a 2012 taxonomic assessment, historically there were four reed-warbler species in the Mariana Islands, the Guam Reed-warbler Acrocephalus luscinia (Guam), the Nightingale Reed-warbler Acrocephalus hiwae (Saipan and Alamagan), the Aguijuan Reed-warbler A. nijoi (Aguiguan or Aguijuan), and the Pagan Reed-warbler A. yamashinae (Pagan). Between 2008 and 2010 we surveyed for three of these species on Alamagan, Aguiguan, and Pagan. Our results indicate that reed-warblers are extinct on Aguiguan, likely extinct on Pagan, and only the Nightingale Reed-warbler on Alamagan and Saipan remains. We estimated the global population at between 1,019 and 6,356 birds (95% CI; mean estimate 3,688), which has declined by more than 1,000 birds since the first quantitative surveys were conducted in 1982, i.e. a 24% decline in 28 years. Camp et al . (2009) describe the status of the Nightingale Reed-warbler on Saipan, which has also declined. We estimated the Alamagan population to be between 428 and 1,762 birds in 2010 (mean estimate 946). Thus, the Alamagan population is ~25 % of the global population, and it has declined slightly since 2000. This decline was not significant but is concerning, especially given a similar decline on Saipan. Restoration and protection of tall-stature native and secondary forest could benefit the Alamagan population, as would similar conservation on Saipan that includes wetland habitat. After suitable restoration of forest and wetland habitats on Aguiguan, Guam and Pagan, individuals from Alamagan and Saipan could serve as founder populations. Careful consideration of the extent and habitat preference of individuals translocated to Tinian, where an unknown reed-warbler species previously occurred, is warranted.

This paper is a status assessment of Hawaiʻi's dry grasslands and shrublands, including its pre-human condition; current status, stressors, and conservation efforts; and future viability. Dry grasslands and shrublands in Hawaiʻi, including dry cliffs, generally have a hot and dry climate with relatively low annual rainfall and are characterized by being located in lowland, montane-subalpine, or alpine zones. These zones are differentiated by elevation and climate, which primarily dictate which species can exist in them (Gagne and Cuddihy, 1999). Prior to human arrival, dry grasslands and shrublands occurred on all of the main Hawaiian islands as well as Nihoa and Mokumanamana (Necker) in the Northwestern Hawaiian islands. Currently, they are still found on the same islands. However, the extent of the native species-dominated parts of this ecotype has greatly reduced in size. In addition to native sub-ecotypes, introductions of nonnative species resulted in two new sub-ecotypes referred to as introduced dry grasslands and introduced dry shrublands, which have become widespread. Our assessment of dry grassland and shrubland viability, defined as the likelihood of persistence over the long term, is based on the concepts of resiliency, redundancy, and representation. The main stressors to dry grasslands and shrublands have been identified as invasive ungulates, invasive plants, invasive herbivores, fire, drought, natural disasters, climate change, and human development. Conservation efforts help to protect and restore native areas of dry grasslands and shrublands, and largely depend upon the actions of Federal, State, private, and multi-agency partnerships. The level of these conservation efforts and their impact on stressors determines the future viability of Hawaiʻi's dry grasslands and shrublands.

We present a status assessment of the Mariana Islands archipelago (Marianas) forests, including the current status, stressors, and future viability. Forests in the Marianas generally receive moderate to high rainfall during distinct wet and dry seasons and are associated with limestone or volcanic substrates. Prior to the arrival of humans in the Marianas approximately four centuries ago, native forest was the dominant forest type. As a result of natural and anthropogenic disturbance, a proportion of native forest was converted to three additional forest sub-types: secondary, monoculture, and Leucaena forests. Forests were defined and characterized using the classification of landcover types for the Mariana archipelago developed by Amidon et al. (2017). Currently, forests occur on all islands in the archipelago, except for Farallon de Medinilla due to extensive bombing during military operations and continuing volcanic activity on Uracas. The main stressors to forests are invasive species, development, volcanic eruptions, typhoons, and fire. Ongoing conservation efforts include biosecurity measures, protected area and species management, invasive species control, and existing laws and regulations. Forest viability, defined as the likelihood of persistence over the long term, is described based on the concepts of representation, redundancy, and resiliency. We developed four plausible future scenarios, each differing in levels of natural resource management, to evaluate the status of forests into the foreseeable future. Two of the scenarios, which are based on no change in conservation actions (Scenario One; status quo) and a slight increase in conservation actions (Scenario Two) have the highest likelihood of occurring in the foreseeable future while the other two, which are based on a slight to moderate decrease in conservation actions (Scenario Three) and a moderate to large increase in conservation actions (Scenario Four) do not. Scenario One would continue to degrade and fragment native forests and result in reduced resiliency, redundancy, and representation. In Scenario Two, the slight improvements in conservation actions would result in a moderate increases in resiliency, redundancy, and representation.

This paper is an assessment of the Hawaiian Islands mesic forests, including the current status, stressors, and future viability. Mesic forests in Hawaiʻi generally receive between 1200 and 2500 millimeters (mm) of rainfall annually and are found on leeward and windward sides of the islands in lowland or in montane-subalpine zones (Cuddihy and Stone, 1990). These zones are differentiated by elevation and climate, which primarily dictate which species can exist in them (Gagne and Cuddihy, 1999). Historically, mesic forests in Hawaiʻi were located on all of the main Hawaiian Islands. These forests were distributed across the islands of Oʻahu, Maui, Kauaʻi, and Hawaiʻi, and to a lesser extent, on Molokaʻi and Lānaʻi. Currently, mesic forests are still found on all of the main Hawaiian Islands. However, the quality of these forests are largely composed of a mixture of native/nonnative vegetation. In addition to the native lowland and montane-subalpine mesic forests that characterized mesic forests historically, introduced mesic forests and managed tree plantations are now classified as mesic forests in the main Hawaiian Islands. Our assessment of mesic forest viability, defined as the likelihood of persistence over the long term, is based on the concepts of representation, redundancy, and resiliency. The main stressors to mesic forests are invasive ungulates, invasive plants, plant disease, invasive herbivores, wildfires, drought, natural disasters (i.e., hurricanes), and agriculture and human development. Ongoing conservation efforts are helping to protect mesic forests in Hawai‘i. The conservation of mesic forests depends largely on combined efforts of State, Federal, multiagency organizations, nonprofit organizations, and the voluntary support of private landowners.

This paper represents a status assessment of the Hawaiian archipelagos wetlands including the current status, stressors, and future viability. Wetlands in the Hawaiian archipelago encompass all fresh and saline lentic (standing or still water) ecotypes occurring from sea level to upper elevations. Wetlands can be separated into two categories: wetlands (bogs, upland marshes and swamps; lowland freshwater and saline marshes, and estuaries) (Polhemus et al., 1992) and water bodies (ponds, fresh and saline lakes, anchialine pools, and artificial reservoirs). Historically, wetlands were located on all of the main Hawaiian islands and a few of the Northwestern Hawaiian Islands (NWHI). Currently, wetlands are still found on all the main Hawaiian Islands and Midway and Laysan in the NWHI. However, the quality of many of these wetlands is now comprised of non-native vegetation, invertebrates, and fishes. In addition to naturally formed wetlands and water bodies, artificial reservoirs (i.e., wastewater treatment plants and stock ponds) are also classified as wetlands in the main Hawaiian islands. Our assessment of wetland viability, defined as the likelihood of persistence over the long term, is based on the concepts of representation, redundancy, and resiliency. The main stressors of wetland viability are development and altered hydrology, recreation and human access, water pollution, invasive animals and plants, sea level rise, flooding and erosions, natural disasters (i.e., hurricanes), and drought. Ongoing conservation efforts are helping to protect remnant patches of natural wetlands in the Hawaiian archipelago. The conservation of these habitats depends largely on combined efforts of State, Federal, multi-agency organizations, non-profit organizations, and the voluntary support of private landowners. An analysis of four future scenarios identified a decline in wetlands viability in lieu of intensive management.

This article provides an overview of the wet grassland and shrubland biome of the Hawaiian Islands, and includes an assessment of its current status, stressors, and future viability. Wet grassland and shrubland in Hawaiʻi generally have high rainfall and occur on the wet, windward sides of the main Hawaiian Islands in montane and lowland zones (Gagné and Cuddihy, 1990). Native wet grassland and shrubland consists of wet sedgelands and grasslands, dominated by different Carex species and native grasses, and native shrubland that occurs primarily on ridge crests and steep cliffs. The main stressors to this biome are introduced ungulates (goats, pigs, and sheep), invasive plants, and natural disasters (i.e., hurricanes or landslide). With the introduction of ungulates and invasive plants in the 19th and 20th centuries some native wet grassland and shrubland biome became degraded, and communities of introduced grasses and shrubs became established. Conservation management to protect native grassland and shrubland include weed control, fencing, and ungulate removal, and depends on combined efforts of State, Federal, and multiagency organizations and nonprofit organizations and the voluntary support of private landowners. We base our assessment of wet grassland and shrubland viability in the future on the concepts of representation, redundancy, and resiliency, which we define in this article. We examine condition of wet grassland and shrubland biome in the foreseeable future (to year 2035) based on potential changes in three conservation management parameters: funding and public support for conservation management; conservation and biosecurity-related laws; and State/civic planning for conservation planning and land use and development.

The following analysis represents the results of a status assessment for the developed system in the Hawaiian Islands including its current status, stressors, conservation efforts, and future viability. The developed system occurs primarily in lowland areas with some in mid- and high elevation areas. There are five categories with varying amounts of vegetation, impermeable surfaces (e.g., roads, buildings), and permeable surfaces. Biodiversity within the developed system is lower compared to the other systems and is generally dominated by nonnative species. Currently, the developed system in Hawaiʻi occurs on each of the eight main Hawaiian Islands with Niʻihau, Kahoʻolawe, and the Northwestern Hawaiian Islands (NWHI) comparatively containing very little. Our assessment of developed system viability, defined as the likelihood of persistence over the long term, is based on the concepts of representation, redundancy, and resiliency. The main stressors on the developed system are insects and disease, axis deer, fire and drought, altered hydrology, pollutants, and land use changes. Ongoing conservation efforts are helping to address each stressor. The conservation of the developed system depends on combined efforts of State, Federal, and multi-agency organizations, watershed partnerships, private landowners, and passive/social management through policies, laws, and land protection.

This article represents a status assessment of the Mariana Islands developed system, including the current status, stressors, and future viability. Developed systems within the Marianas Archipelago exist where there are human populations, primarily focused on the coasts of Guam, Saipan, Rota, and Tinian Islands. The quality of the developed system is largely composed of a mixture of nonnative vegetation types, and predominantly nonnative wildlife. Our assessment of the developed system viability, defined as the likelihood of persistence over the long term, is based on the concepts of representation, redundancy, and resiliency. The main stressors to developed systems are effects of climate change, additional development, typhoons, pollution and invasive species. Ongoing conservation efforts are helping to protect plants and wildlife within developed systems, and the conservation depends largely on combined efforts of State, Federal, multiagency organizations, nonprofit organizations, and the voluntary support of private landowners. The Marianas developed system represents a unique land use type, whose composition is dynamic across its range. Due to growing human population numbers, the developed system is likely to decrease in size over the coming years, as development increases. Projections for the persistence of developed systems in the Marianas largely depends on the conservation actions taken, which should be implemented to safeguard pockets of biodiversity found within these systems.

We provide an overview of the coastal ecosystem of the Hawaiian archipelago and describe the ecological factors that have influenced the ecosystem in the past, present, and future. Coastal ecosystems found throughout the Hawaiian archipelago are subject to oceanic influences such as winds, salt-spray, and wave energy. Two coastal ecosystem sub-types occur in the archipelago and are defined by moisture regime: coastal dry and coastal wet-mesic sub-types. Limited information exists about what coastal ecosystems and their associated ecological communities looked like prior to human-contact. The assumption is that coastal ecosystems were historically more resilient to stochastic events because they had more continuous populations of native flora with a higher faunal diversity. Currently, coastal ecosystems are in decline due to factors such as conversion pressure from expanding development and agriculture and the introduction of invasive species. We analyzed four scenarios for a foreseeable future of coastal ecosystems with varying levels of change in Conservation Management Parameters: conservation values, laws and biosecurity, and development or conservation planning. We anticipate that coastal ecosystems will continue to decline unless significant management change occurs.

The Mariana archipelago consists of an island arc formed as the Pacific plate converges with the Philippine plate in a subduction zone where the older, more dense Pacific plate sinks and moves underneath the Philippine plate creating the deepest location known on earth—the Marianas Trench. The islands in the north part of the arc are younger, active volcanoes, whereas the older islands in the south are volcanic remnants that have layers of limestone from a time when they were once below sea level. The Mariana archipelago has two distinct seasons, wet, and dry. The climate is mild; however, the archipelago is prone to typhoons. Because the Mariana archipelago has no elevation extremes, it does not host a wide variety of biomes. Here we focus on the physical features of the Mariana archipelago.

This article represents an assessment of Mariana Island Wetlands that includes the current status, stressors, and future viability. Wetlands in the Mariana Islands are comprised of the following categories: estuarine wetlands, forest wetland/swamps, freshwater marshes, lakes, and artificial wetlands. Wetlands have been significantly impacted by human habitation in the islands, with many degraded, fragmented, or lost due to development, invasive species, fire, erosion, altered hydrology, agriculture, and pollution. Hydrophytic vegetation is primarily composed of species of grasses, reeds, ferns, and trees. Wetlands provide habitat for some species listed as endangered, while a couple of species reliant on wetlands have been extirpated. Variables considered in analyzing current condition and future scenarios include stressors as well as conservation efforts. Considering the vulnerability of the wetlands and limited representation across the islands, as well as climate-related changes, it is anticipated that these habitats will continue to degrade in the absence of intensive or consistent management into the future.

We present a status assessment of the Hawaiian islands dry forests, including the current status, stressors, and future viability. Dry forests generally have relatively low rainfall and are found on the leeward sides of the islands in lowland or in montane-subalpine zones. Historically, dry forests were located on all of the main Hawaiian islands and currently they are still found there. However, the quality of these forests is largely composed of a mix of native/nonnative vegetation. In addition to the native lowland and montane-subalpine dry forests that characterized dry forests historically, introduced dry forests and tree plantations are now classified as dry forests. Our assessment of dry forest viability, defined as the likelihood of persistence over the long term, is based on the conservation biology concepts of representation, redundancy, and resiliency. The main stressors to dry forests are invasive ungulates, plants, other herbivores, wildfires; drought; and agriculture and human development. Ongoing conservation efforts help to protect remnant patches of dry forests but this depends largely on combined efforts of various stakeholders. We developed four plausible future scenarios, each differing in levels of natural resource management, to evaluate the status of dry forests into the foreseeable future. Two of the scenarios, which are based on no change in conservation actions (Scenario One; status quo) and a slight increase in conservation actions (Scenario Two) have the highest likelihood of occurring in the foreseeable future while the other two, which are based on a slight to moderate decrease in conservation actions (Scenario Three) and a moderate to large increase in conservation actions (Scenario Four) do not. Scenario Three would severely degrade and fragment native dry forest and result in reduced resiliency, redundancy, and representation. In Scenario Four, the substantial improvements in restoration of native dry forests would result in increased resiliency, redundancy, and representation.

This article provides an overview of the savannas of the Mariana island archipelago (Marianas) savanna biome, including current status, stressors, and future viability. Across the Marianas, savannas are typically found in mountainous areas formed by volcanic action. Tropical savanna are associated with the tropical wet and dry climate and develop in a seasonal forest of climax regions. However, edaphic conditions or disturbances prevent the establishment of species of trees associated with the climatic community (Woodward, 2012). Savanna in the Marianas generally receive between 50.8 and 127 cm (20–50 in.) of rainfall annually and are characterized by a predominance of grass and other herbaceous species with some small trees and shrubs (Webber et al., 2007). Currently, savanna ecotypes in the Marianas are experiencing severe erosion, forming badlands, which are challenging to control and restore back to native systems. Our assessment of savanna viability, defined as the likelihood of persistence over the long term, is based on the concepts of representation, redundancy, and resiliency. The main stressors to savanna in the Marianas are development, invasive species, erosion caused by recreational off-road vehicle use, fires, typhoons and drought. Current ongoing conservation efforts by Federal, State, and private entities and agency partnerships combined with certain laws and regulations limit some of the effects of stressors on the ecotype, but do not eliminate them. A stronger effort to engage partners and stakeholders in identifying and prioritizing landscape areas required for the conservation of native ecosystems, and to actively restore and expand these areas is needed for the successful conservation of savannas.