Browsing by Author "Jacobi, James D."

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    Assessment of fuels, potential fire behavior, and management options in subalpine vegetation on Mauna Kea Volcano, Hawai`i
    (2009-11) Thaxton, Jarrod M.; Jacobi, James D.
    Fire is a major threat to habitat for the endangered Palila (Loxioides bailleui) within subalpine vegetation on Mauna Kea volcano, Hawai‘i. The presence of large amounts of fine fuel from grasses, dry climate, and human ignition sources produces a significant risk of wildfire in this area year-round. The purpose of this report is to provide information on fuels and potential fire behavior that will contribute to fire management of Palila habitat. Recommended actions will contribute to the conservation of these native forests and facilitate restoration in degraded areas. To assess the effects of grass invasion on fuel conditions and potential fire danger, we quantified vegetation and fuels across an elevation gradient from grasslands into sub-alpine forests on the west slope of Mauna Kea. Our results indicated that grass cover was reduced under tree canopy in plots below ~2,500 m elevation, but at higher elevations grass cover was higher under trees than in the open. However, tree canopy cover below 2,500 m elevation was not high enough overall (~25% on average) to result in significant reductions in fine fuels at the landscape level. Sampling directly under and away from tree crowns at multiple elevations suggested that below ~2,500 m, the presence of tree canopy cover can reduce grass fuels significantly. Furthermore, moisture content of live surface fuels was increased under tree canopy compared with open areas. These results suggest that restoration of forest cover may have the potential to alter grass fuels in ways that decrease the threat of fire in some subalpine forests. Fire behavior estimates based on fuel data from grasslands, mixed forest and māmane forest indicated the need for fuelbreaks of at least 20-30 m to limit fire spread in most areas. In many cases, breaks as wide as 40 m are required to limit fire spread risk under extreme weather conditions. Based on our fuels data and fire behavior predictions, recommended actions include: (1) construction of new or expansion of existing fuelbreaks to immediately reduce fire risk to the most sensitive areas adjacent to the core Palila population on the southwest slope and the translocated Palila population on the north slope of Mauna Kea, (2) enhancement of forest restoration activities to increase fuel moisture and reduce grass fuel loads (3) installation of water sources (diptanks) in both areas to decrease firefighter response time, and (4) increased public education and awareness with regard to fire danger on Mauna Kea.
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    Baseline survey for rare plant species and native plant communities within the Kamehameha schools' Lupea Safe Harbor Planning Project Area, North Kona District, Island of Hawai`i.
    (2010-12) Jacobi, James D.; Warshauer, Frederick R.; Price, Jonathan P.
    Kamehameha Schools, in conjunction with several federal, state, and private organizations, has proposed to conduct conservation management on approximately 5,340 ha (~13,200 acres) of land they own in the vicinity of Kīpukalupea in the North Kona District on the island of Hawai`i. The goal of this program is to restore and enhance the habitat to benefit native plant and animal populations that are currently, or were formerly, found in this site. The initial phase of this project has been focused on various activities including conducting baseline surveys for bird and plant species so Kamehameha Schools could develop a Safe Harbor Agreement (SHA) for the proposed project lands relative to the habitat management and species reintroduction efforts they would like to conduct in the Lupea Project area. This report summarizes methods that were used to collect field data on plant species and communities within the project area, and the results of that initial survey. The information was used to calculate baseline values for all listed threatened or endangered plant species found, or expected to be found, within the project area, and to design a monitoring program to assess changes in plant communities and rare plant species relative to management activities over the duration of the SHA. The Lupea Project area contains excellent examples of several high elevation native plant communities including montane dry forest and woodland, native subalpine shrubland, and native grassland. Between November 2003 and January 2004 we sampled plant communities and species along seven transects established through the project area. A total of 109 plant species were found during this survey, within the transect grid and in nearby areas. Forty-four of these plants are endemic species, 21 are indigenous species, 43 are introduced, and one species is believed to have been introduced to Hawai`i by early Polynesian settlers. Only one federally listed Endangered plant, Asplenium peruvianum var. insulare, was found within the survey area. Additionally, we found one immature plant that may be Sicyos macrophyllus, a candidate species for listing.However, we were not able to make a definite determination of this species‟ identity since it did not have fruits or flowers. Finally, we documented four plant species within the survey area that have no official status designation but are considered to be rare and informally recognized as “species of concern” (SOC) as they appear to be declining in distribution and abundance statewide. These included Chamaesyce olowaluana, viii Eragrostis deflexa, Sisyrinchium acre, and Tetramolopium consanguineum. In addition to conducting field surveys, we performed a query on a spatial database developed by Dr. Jonathan Price of the University of Hawai`i at Hilo which models the potential range of all native Hawaiian plant species based on historic observations and a set of environmental parameters. The potential species list for the Lupea Project area includes 47 taxa that we did not find during our surveys, as well as three other listed species that were not modeled by Price, but known from historic records in adjacent habitats. Some of these species are extremely rare or, in some cases have been locally extirpated. However, most of the plants that were predicted but not found during our surveys are expected to be located with additional searching, or may potentially recolonize the area following the elimination of ungulates and initiation of other restoration efforts. Forty-four introduced plant species were found within the survey area, seven of which are considered to be highly invasive. These include the grasses Pennisetum clandestinum and Pennisetum setaceum, vines Delairea odorata and Passiflora tarminiana, herbs Senecio madagascariensis and Verbascum thapsus, and the shrub Rubus niveus. Non-zero baseline values are proposed for the one listed plant species found within the Lupea Project area, one species that is a candidate for listing, and the four other rare species we found that may be considered for listing in the future. Additionally, a zero baseline is proposed for 23 other species that were predicted, but not found within the project area. These include 14 Endangered species, one Threatened species, two candidates for listing, and six species of concern. Subsequent monitoring of the site will be necessary to determine if the populations of these species have increased or decreased relative to their baseline values. It is presumed that the management activities Kamehameha Schools has proposed for this area, particularly removal of the ungulates and weed control, will provide a benefit to the habitat as a whole and allow for natural regeneration and maintenance of the all elements of the plant communities found there.
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    Mapping plant species ranges in the Hawaiian Islands: developing a methodology and associated GIS layers.
    (2007-11) Price, John P.; Gon III, Samuel M.; Jacobi, James D.; Matsuwaki, Dwight
    This report documents components of a methodology for projecting the geographic ranges of plant species in the Hawaiian Islands. This consists primarily of the creation of several GIS data layers depicting attributes related to the geographic ranges of plant species. The most important data layer generated here is an objectively-defined classification of climate as it pertains to the distribution of plant species. By examining previous zonal vegetation classifications in light of spatially detailed climate data, we explicitly define broad zones of climate relevant to contemporary concepts of vegetation in the Hawaiian Islands. A second spatial data layer presented here considers substrate age, since large areas of the island of Hawai‘i in particular are covered by very young lava flows, which are inimical to the growth of many plant species. The third data layer presented here divides larger islands, which are composites of multiple volcanoes, into definable biogeographic regions, since many species are restricted to a given topographically isolated mountain or a specified group of these. A final spatial data layer depicts human impact, which reduces the range of many species relative to where they formerly occurred. Several other factors that influence the geographic ranges of species, including topography, soils, and disturbance, are discussed here but not developed further due to limitations in rendering them spatially. We describe a method for analyzing these base layers in a geographic information system (GIS), in conjunction with a database of species distributions, to project the ranges of plant species, including the potential range prior to human disturbance and the projected present range. Examples of range maps for several species are given as case studies that demonstrate different spatial characteristics of range. We discuss several potential applications of species range maps including facilitation of field surveys, informing restoration efforts, studies of range size and rarity, studies of biodiversity, conservation planning, and invasive species management.
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    Monitoring Hawaiian Biodiversity: Pilot Study to Assess Changes to forest birds and their habitat
    (2017-12-12) Gorresen, P. Marcos; Camp, Richard J.; Gaudioso-Levita, Jaqueline M.; Brinck, Kevin W.; Berkowitz, S. Paul; Jacobi, James D.
    Biological diversity, or biodiversity, is the variety and abundance of species in a defined area, and is one of the oldest and most basic descriptions of biological communities. Understanding how populations and communities are structured and change over space and time in response to internal and external forces is a management priority. Effective management practices and conservation strategies depend on our understanding of the relationship between changes in biodiversity and ecological drivers such as invasive species, land use and climate change. To demonstrate how changes in biodiversity may be monitored over a large (400 km2) tract of native forest habitat, we compared bird and plant community composition and structure in an upper montane region of Hawai‘i Island originally surveyed in 1977 as part of the Hawai‘i Forest Bird Survey (Scott et al. 1986) with a comprehensive sample of the same region in 2015. Our findings suggest that across a region spanning an elevation range of 600 to 2,000 m considerable changes occurred in the plant and bird communities between 1977 and 2015. Endemic and indigenous plants species richness (i.e., total number of species) decreased dramatically in the low and middle elevations below an invasive weed front, whereas naturalized plant species richness did not change between the two periods at any elevation. Endemic bird abundance decreased and two species were lost in the lower elevations (< 1,100 m) between 1977 and 2015, while naturalized bird abundance and the numbers of species increased in the same area. In addition to changes in community composition, the structure of the forest showed evidence of changes in dominant and sub-dominant tree canopy cover, shrub and herbaceous cover, dominant tree canopy height, and matted fern cover. Biodiversity monitoring helps to define specific conservation targets and to measure progress towards reaching those targets. It is difficult to ascribe causative factors to a change in biodiversity without directly manipulating the environment. Forest habitat in a variety of settings (i.e., islands and regions with differing land-use histories and elevation ranges), however, can provide opportunities to evaluate the influence of ecological drivers. Declines in native bird biodiversity in low-elevation areas may be attributed to invasive species as land use and climate conditions have remained relatively similar over the 40-year period. Thus, the shift from an endemic-naturalized co-dominated community in 1977 to one dominated by naturalized, alien birds in 2015, and reduction in native bird abundance over that period, may reflect increasing dominance by naturalized plants within this forested area. Inferences drawn from analyses of region-wide surveys, especially with replicate datasets, will facilitate the identification of broad-scale changes in biodiversity, and provide a needed current datum in Hawaiian plant and bird biodiversity monitoring.
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    Native coastal flora and plant communities in Hawai`i: their composition, distribution, and status.
    (2009-12) Warshauer, Fredrick R.; Jacobi, James D.; Price, Jonathan P.
    The Hawaiian coastal flora primarily includes the halophytic (salt-adapted) plants closest to the area of salt spray and wave wash, often concentrated within a distinct strand zone, and usually growing as low mats. However, behind the strand is a zone of vegetation that is quite varied in composition and structure, but somewhat less specialized in life form, which is also adapted to the specific conditions of the coastal environments and to those at different locales. Coastal plant communities in Hawai‘i are distributed across a very wide range of conditions, and are anything but homogeneous. Primary factors that influence their composition and structure include moisture, substrate, and exposure to wind and salt water. Some of these factors also have roles in dispersal, competition, trauma, and periodic reordering of local community compositions. External to these are anthropogenic impacts which may have a similar scale of influences today. Between 2000 and 2005 we surveyed a total of 133 coastal sites on the islands of Moloka‘i, Maui, and O‘ahu. On O‘ahu we visited 28 sites, 50 sites were surveyed on Moloka‘i, 36 sites on West Maui, and 19 sites on East Maui. The survey areas were selected primarily to sample a region’s community variety and composition, and were distributed within the diversity of moisture zones found in the coastal regions of each island. A few sites were visited on Kaua‘i and Hawai‘i, but these islands are in need of much more survey work and thus have limited commentary in the current summary. The smaller main islands (Ni‘ihau, Lāna‘i, and Kaho‘olawe), as well as many of the small offshore islets, were not visited at all in this assessment. During this project we recorded 142 taxa of native plants out of 169 that were expected based on past plant collections and from the literature. A total of 105 coastal plants were recorded on Moloka‘i, 85 on Maui, and 52 on O‘ahu. Thirty-eight species were found on all three of the islands we surveyed, 53 on at least two islands, and 51 plants were found on only one of these islands. We encountered 12 listed endangered taxa, 2 threatened taxa, and 13 species of concern (SOC) but with no official listing status, as well as many other taxa that are now relatively uncommon within the Hawaiian coastal zone. The number of plants per site varied considerably between the areas surveyed, but the greatest diversity was found on Moloka‘i and Maui, with their richest sites containing 30 and 32 species, respectively. On Maui 22 (40%) of the sites had less than10 native coastal plant species, 30 (55%) had 10 – 20 species, and 3 (5%) with more than 20 species. A different situation was found on Moloka‘i where only 10 (20%) of the sites had less than 10 native coastal plant species, 28 (56%) had 10 – 20 species, and 12 (24%) with more than 20 species. On O‘ahu seven (25%) sites had less than 10 native plant species, 20 (71%) had 10 – 20 species, and only one site (Ka‘ena Point) had over 20 species, but, in this case just a total of 21 coastal plant species. The current coastal flora of O‘ahu was somewhat reduced compared to the other two islands, likely a result of the much greater human-related impacts on the coastal zone of O‘ahu. Additionally, the remaining coastal vegetation on O‘ahu is nearly all within the dry zone. The most influential site factor for Hawaiian coastal communities is the range of moisture that occurs across any particular area. The greater the moisture zone range, the more species are likely to be found in a region. The composition of strand communities varies considerably spatially, but in most given locations communitiescontain limited subsets of the species richness potentially available. The coastal vegetation is characterized by low growing and mat forming species in areas closest to the ocean and by taller plants farther inland or where available soil has accumulated locally. In the arid and dry zones, a few annual species, mostly grasses, are seen; the viii rest of native coastal flora is perennial. Exposure to salt water and onshore flow of salt mist (‘ehukai) comprise the harshest ecological factors within the coastal zone. Exposure to ‘ehukai, strong winds, and brackish basal ground water all influence this generalization and add variegation to an area’s vegetation structure and composition. A range in other site conditions helps to further diversify the structural and species composition of the communities. Understanding of these conditions can assist managers with identification of areas to preserve and manage, and help to guide restoration attempts. Alien plants represent one of the greatest threats to native coastal vegetation in that any one of several invasive species can completely displace or prevent the colonization of entire suites of native species. Alien animals are another important threat, one that frequently opens the door for, or tips the balance to, alien plants. The most obvious and widespread animal species are pastured and free-roaming ungulates, particularly cattle, goats, sheep, pigs, and deer. The numbers and distributions of some ungulate species may have surged and waned variably over time and space, but their impacts are unequivocally negative in the coastal zone in any abundance. Human development and use of coastal areas continues to exert severe, usually permanent, impacts to remaining native coastal vegetation. Recreational activities, in particular, tend to be a widespread detriment to coastal plant communities. The fragmentation of habitats and compounding affects of an associated array of disturbances resulting from urban and agricultural activities have led to considerable attrition of species from predominately native dominates areas in the coastal zone. These losses are continuing, perhaps accelerating, with the expanding use of the limited coastal areas throughout the islands for resort, residential, and recreational activities. Given the cumulative stresses that Hawai‘i’s coastal communities have experienced in recent years, the few plant extinctions that have occurred in that habitat indicates there is still time to employ effective management to prevent more loss of diversity. However, the widespread damage to coastal vegetation and the rarity of so many species indicates the urgency for supplying sufficient targeted management to preserve species and to restore community composition, structure, and function. The coastal vegetation’s adaptation to natural disturbance, as evident from the harsh environment it occupies, coupled with its regenerative capability, may have helped these communities survive thus far. This suggests a good potential for preservation of the biota of these regions if effective and strategic management actions are effected soon. A conservation strategy that incorporates both protected regions and species augmentation may be able to reverse declining trends in Hawaiian coastal communities if applied in time and at sufficient scale. Protection of coastal regions should feature reduction or elimination of the major stress factors that accompany alien plants and ungulates, as well as reducing and compensating for the adverse consequences of land use. A number of sites on each island stand out with high species diversity and/or populations of rare plant species, as well as still having an established connection with contiguous lowland vegetation. These sites can serve as core areas for a regional approach to managing strips of coastal communities and their associated lowland vegetation. The following conclusions and potential management strategies have been derived from our survey observations:  A regional approach to coastal resource conservation is likely to be the most effective approach to secure an island’s native coastal vegetation.  It is important to identify and prioritize coastal vegetation areas that still retain connections to native lowland plant communities. Even depleted communities can still contribute to the coastal areas’ biodiversity, and both could be stabilized ix and augmented where warranted. Managing both coastal and lowland areas together can be an efficient strategy for conserving a variety of resources and processes across modestly-sized areas.  Removal or significant reductions of feral ungulates is one of the most pressing management needs along certain stretches of the coastlines of the main Hawaiian Islands. Strategic fencing can be an effective tool for excluding ungulates and potentially predators. However, high installation and maintenance costs limit their use presently, particularly near shorelines. Development of cost effective corrosion-resistant materials and appropriate designs could encourageincreased use of fences in coastal areas.  Given the ongoing spread of numerous alien plants into new regions, immediate removal of the early colonizing individuals of particularly threatening species from native coastal vegetation can proactively prevent an increase in ecosystem disruption.  Expand public education and outreach programs to enlist more support of coastal community conservation from the public. These surveys have provided more and current information on the ecology, composition, distribution, and status of coastal plant communities and species in selected portions of the main Hawaiian Islands. Although not as rich in endemic species as are upland communities, the Hawaiian coastal flora is relatively diverse, and taken as a whole, is still quite intact with very few historically known species that are now extinct. Although the coastal zone has been heavily impacted over the past 250 years, many high quality examples of diverse plant communities can still be found, particularly in the wet and mesic habitats on the islands of Maui and Moloka‘i. Management efforts that are regionally focused on reducing the impacts of invasive species (both plants and animals) and maintaining the connection between the coastal strand and lowland vegetation, coupled with expanding public awareness of the value of coastal communities, can allow for effective restoration and maintenance of this unique set of ecosystems for the future.
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    Rapid assessment of vegetation at six potential `Alala release sites on the island of Hawai`i
    (2007-10) Price, John P.; Jacobi, James D.
    The U.S Fish and Wildlife Service (FWS), as part of its participation in the effort to recover the endangered ‘Alalā (Corvus hawaiiensis), is supporting efforts by the ‘Alalā Recovery Team (ART) to rank areas for suitability as reintroduction sites for this species. A part of this ranking exercise is determination of the current state of the vegetation present at the sites. Although some of these sites have been surveyed using various methods in the recent past, specific, comparable measurements of key aspects of the plant communities are needed for ranking sites for ‘Alalā recovery. Here we summarize new and compiled data for each of the release sites that address the current status and potential recovery of the tree canopy and understory vegetation relative to potential suitability for ‘Alalā release. This project focused on two objectives: 1) Assess the current status and distribution of forest canopy cover based on an analysis of recent satellite imagery and other spatial datasets, and 2) Collect new field data from the six potential release sites to provide quantitative information on the status of the vegetation, with particular focus on density and species composition of plants used by ‘Alalā as food, overall density of forest understory, and degree of closure of tree canopy. The field data also served as ground-truth points for the spatial analysis. The methods of assessing habitat potential for ‘Alalā recovery presented here represent a simple measure of vegetation attributes taken from a limited number of plots within each study area. A primary problem is in attempting to summarize large study areas that incorporate considerable variation in climate, substrate, and land use history. An examination of several versions of the preferred food species richness value ranks the two Ka‘ū study sites first and second. This study does not consider the amount of fruit produced by different species, and therefore it is possible that some additional weighting of preferred food plants might better quantify food resource availability in different landscapes. We also assessed continuity of forest units with other similar habitats outside the study areas, the amount of site disturbance as indicated by percent cover by alien grass species, as well as several other combinations of variables that may help in ranking the sites.
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    Status and trends of native birds in the Keauhou and Kilauea Forest, Hawai`i Island.
    (2010-05) Camp, Richard J.; Jacobi, James D.; Pratt, Thane K.; Gorresen, P. Marcos; Rubenstein, Tanya
    A Safe Harbor Agreement (SHA) is a voluntary arrangement between the U.S. Fish and Wildlife Service and non-Federal landowners to promote the protection, conservation, and recovery of listed species without imposing further land use restrictions on the landowners. Kamehameha Schools is considering entering into a SHA for their Keauhou and Kīlauea Forest lands on the island of Hawai′i. Bird surveys were conducted in 2008 to determine the current occurrence and density of listed species for the Keauhou and Kīlauea Forest, a prerequisite for establishing an agreement. Because of different management practices in the proposed SHA area we stratified the survey data into intact and altered forest strata. The listed passerines—′Akiapōlā′au (Hemignathus munroi), Hawai′i Creeper (Oreomystis mana), and Hawai′i ′Ākepa (Loxops coccineus)—occur in both strata but at low densities. The endangered ′Io (Hawaiian Hawk; Buteo solitarius) also occurs within both strata at low densities. This report was prepared for the U.S. Fish and Wildlife Service and Kamehameha Schools to provide information they can use to establish baseline levels for the SHA. In addition, we describe the status and trends of the non-listed native birds.