Tropical Conservation Biology and Environmental Science

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A COMPARATIVE CO2 LIFE CYCLE ANALYSIS OF THREE NUTRIENT SOURCES FOR A NOVEL OFFSHORE MACROALGAE FARM IN HAWAI’I
(2022-12) Chambers, Trevor; Hopkins, Kevin; Tropical Conservation Biology & Environmental Science
A Global Ecological Signal of Extinction Risk in Marine Ray-Finned Fishes
(2022-05) Bak, Trevor; Knope, Matthew; Tropical Conservation Biology & Environmental Science
A TEST OF HOST-TAXON, ENVIRONMENT, AND DISTANCE EFFECTS ON LEAF FUNGAL ENDOPHYTES IN METROSIDEROS ON THE ISLAND OF O‘AHU
(2019-12) Sur, Gary; Ostertag, Rebecca; Sutton, Jolene; Tropical Conservation Biology & Environmental Science
Addressing angiostrongyliasis on Hawai'i Island with research, education outreach, and host control
(2016-12) Howe, Mary Kathleen; Jarvi, Susan I.; Tropical Conservation Biology & Environmental Science
Hawaii Island has the highest incidence of rat lungworm disease (RLWD) of all the Hawaiian Islands and the mainland United States. The relatively recent introduction of the semi-slug Parmarion martensi, an effective intermediate host, and the wide-spread use of rainwater catchment systems may play a role. Studies were designed to investigate the ability of drowned gastropods to shed larvae, the location in a water column where larvae would most likely be found, the potential for larval passage through a 20μm filter, and the ability of the larvae to survive outside the slug/snail host. Whole P. martensi shed many, viable A. cantonensis larvae with >90% of larvae found in samples taken from the bottom of the water column, suggesting they may settle near the bottom of a catchment tank. Larvae that were able to pass through a 20μm sieve could not survive acid, were active for at least 56 days outside the slug host, and tested positive for RLW by qPCR. Larvae that could not pass through a 20μm sieve were able to survive HCl-pepsin, were active for at least 21 days, and tested positive for RLW. First stage larvae can survive gut acid when swallowed after migration from the lungs but cannot withstand acid immersion again until they become third stage larvae.The study results merit further investigation into the potential link between poorly maintained rainwater catchment systems and the high incidence of RLWD on Hawaii Island, and the studies clearly demonstrate the need for control of hosts of Angiostrongylus cantonensis. Hawaii’s remote location makes food security an important issue. State-wide efforts to promote the Grow Local, Eat Local movement are reflected in the growing number of residential gardens, small farms, farmers’ markets, school and youth garden projects, and the recent passage of the Farm to School Bill. However, efforts to educate farmers, food handlers, and consumers about rat lungworm disease and the need for disease prevention and host control has not been similarly supported. In collaboration with five partner schools on Hawaii Island, the University of Hawaii, Daniel K. Inouye College of Pharmacy’s Hawaii Island Rat Lungworm Working Group worked with students and teachers to develop an integrated pest management plan for school garden projects. Integrated pest management allows for the careful consideration of applications available to control a pest event and chooses those practices that are least harmful to human and environmental health. These best practices include preventative cultural practices, monitoring, mechanical control, biological control, and the responsible use of pesticides. Students were intensively educated about RLWD, the parasite’s life cycle, and prevention measures. Using best management practices, we set up traps and collected data on gastropod species abundance, and shelter-type capture rate. Integrating STEM curriculum makes the project attractive to schools as it supports student academic success. Adoption of this management project by the many school and youth garden projects in areas of RLWD can exponentially increase community awareness, encourage control efforts, and potentially map disease risk.
ADDRESSING OBSTICLES TO DEVELOPING OYSTER CULTURE IN HAWAIʻI
(2016-12) Petersen, Forrest S.; Haws, Maria C.; Tropical Conservation Biology & Environmental Science
A series of experiments was conducted on Oʻahu, Molokaʻi and Hawaiʻi Islands to examine specific factors that contribute to the feasibility of oyster culture for the state of Hawaiʻi. Two simultaneous studies were performed to measure the growth and condition index of five families of Crassostrea gigas (Pacific oyster) grown in the traditional Hawaiian fishponds of Heʻeia, Oʻahu, and Keawanui, Molokaʻi. Three of the oyster families (AA, AE, and EE) were produced by the Molluscan Broodstock Program (MBP) at Oregon State University. Two additional oyster varieties studied were the Midori strain of C. gigas, and a naturalized C. gigas strain found at Heʻeia fishpond called Oʻahu oysters. Oysters grew significantly faster in Keawanui than in Heʻeia fishpond (P = 0.004). There were significant differences in growth between the five families grown in Keawanui Fishpond (P = 0.035) but no significant difference was found between the same varieties grown at Heʻeia. Oysters grown in fishponds exhibited extremely high growth rates in excess of eight mm per month but suffered high mortality rates due to predation, biofouling and summer mortality. Midori oysters cultured in Hilo Bay, Hawaiʻi, had a significantly higher condition index than triploid or MBP oysters (P = 0.002). Regression analysis revealed that predation accounted for 57% of the variance in oyster mortality observed in Hilo Bay (P < 0.0001). Chlorophyll a was found to be a significant predictor for oyster growth, accounting for 40.8% of the variance in oyster growth in the Hilo Bay experiments (P < 0.0001). Analysis of various pest eradication treatments showed that the Super Salty Slush Puppy (SSSP) treatment adapted from Cox. et al. (2011) proved to be the most effective for removing the parasite Polydora websteri (oyster mudworm) from oysters without causing additional oyster mortality (P < 0.0001).
AGROFORESTRY RESOURCES, GENDER AND LOCAL KNOWLEDGE IN HAWAIʻI
(2024-12) Ezzy, Anna Nalani; Besio, Kathryn; Tropical Conservation Biology & Environmental Science
An Assessment of Nysius wekiuicola Populations and Thermal Microhabitat Conditions on Cinder Cones of the Maunakea Volcano, Hawai‘i
(2018-02) Kirkpatrick, Jessica Ann; Eiben, Jesse A.; Tropical Conservation Biology & Environmental Science
The endemic Hawaiian wēkiu bug (Nysius wekiuicola) is a carnivorous scavenger that only inhabits volcanic cinder cones above ~3,500 m elevation on the mountain, Maunakea, Hawai‘i. As a species of conservation concern threatened by invasive species, climate change, and habitat alteration, a greater understanding of wēkiu bug populations and habitat use through time is needed to inform habitat restoration efforts and conservation management decisions. In this study, locations on a high elevation and a lower elevation cinder cone were sampled using attractant traps in a buffered random design six times from June 2016- 2017 to examine wēkiu bug distribution patterns within cinder cone habitats and across seasons. A generalized linear mixed model (GLMM) was used to explore the relative importance of cinder cone characteristics (topographic aspect, surficial minerals, and elevation) hypothesized to influence wēkiu bug distributions. Additionally, thermal conditions were described and compared within the insects’ habitat (within 2-30 cm depth of cinder substrate). Results indicate that wēkiu bugs had a highly aggregated distribution, with up to 40 times higher bug densities at the higher elevation cinder cone, and the density of bugs changed within and between cinder cones throughout the year. Our GLMM indicated that sample month, topographic aspect, and elevation on a cinder cone influences wēkiu bug distributions with abundance increasing with elevation within a cinder cone, and the highest captures are predicted to be on the northeast aspects of the higher elevation cinder cone year-round. Temperature data shows multiple microclimates exist throughout cinder cone habitats at any given time, and the ash substrate layer could provide an important habitat refuge for the wēkiu bug, as this layer rarely freezes. We recommend preserving contiguous cinder cone habitats for the persistence of the wēkiu bug, and monitoring populations in a random sample design in known or restored habitats to effectively monitor wēkiu bug densities.
Applying Makawalu to Midway Atoll's Visitor Program Kuaihelani, Papahānaumokuākea Marine National Monument
(2019-05) McGuire, Gina Maelynn; Turner, Jason P.; Tropical Conservation Biology & Environmental Science
This study informs decisionmakers on the stakeholder's views about the feasibility of re-opening visitation to the Midway Atoll National Wildlife Refuge and Battle of Midway National Memorial. Midway Atoll is operated under the National Wildlife Refuge System and is the only area within the surrounding Papahānaumokuākea Marine National Monument designated to allow for public visitation. Narrative research methodologies including interviewing and participant observation were conducted under the Hawaiian framework of makawalu, literally translating to “eight eyes.” Narrative research provides the context and added complexity to inform decisions about visitation regarding social, ecological, heritage, and economic interests in the Atoll. Stakeholder responses show that the question as to whether visitation “should” be re-opened on Midway is unclear across responses, and that in many cases where there is strong conviction to have visitation, it is only for certain groups and interviewees have serious reservations about visitation program design. Spatial landscape analysis identifies gaps in data availability to determine potential environmental impact on Midway Atoll and the importance of including Indigenous ways of knowing in management. The literature review of similar sites shows that the effects of increased human activity are often greater than anticipated or immediately observable. Significant logistical challenges of operating in a remote setting result in high annual program and trip costs. Future planning should incorporate stakeholder views, information on potential environmental harm, and associated costs collected in this document to inform whether or not the benefits of visitation outweigh concerns and the high cost.
APPLYING MERISTEM TIP CULTURE AND THERMO THERAPY TO ELIMINATE VIRUSES FROM PINEAPPLE (ANANAS COMOSUS) AND TARO (COLOCASIA ESCULENTA)
(2020-05) Domingo, Ryan S.; Shintaku, Michael; Tropical Conservation Biology & Environmental Science
APPLYING OBJECT DETECTION TO MONITORING MARINE DEBRIS
(2020-05) Sherwood, Leah; Peterson, Michael; Tropical Conservation Biology & Environmental Science
ARE SYMBIOTIC NITROGEN FIXATION STRATEGIES TIED TO INVASIVENESS FOR NON-NATIVE WOODY LEGUMES IN HAWAIʻI?
(2020-05) Kirby, Angalee; Ostertag, Rebecca; Tropical Conservation Biology & Environmental Science
Arthropod Diversity Estimates for Three Native Subalpine Plant Species on the Maunakea Volcano of Hawai‘i Island
(2016-12) Stever, Heather; Eiben, Jesse; Tropical Conservation Biology & Environmental Science
Terrestrial arthropods are among the most abundant and diverse animals on Earth, especially in Hawai‘i where they constitute the vast majority of endemic fauna and play crucial roles in nearly every habitat throughout the islands. Arthropod surveys and inventories are useful methods for documenting arthropod diversity, but studying arthropods can be extremely difficult. Arthropod collection is often taxing because many species are very mobile and exist in harsh climates or on terrain that is difficult to access. Arthropod identification can also be challenging since many arthropods are remarkably small with complex morphologies and diverse life histories. The main goals of this study are to (1) broaden scientific knowledge regarding Hawaiian arthropods by conducting a baseline inventory of the arthropod diversity associated with three endemic Hawaiian plant species in Maunakea’s subalpine region: ‘Āweoweo (Chenopodium oahuense), Hinahina (Geranium cuneatum); and Māmane, (Sophora chrysophylla), and to (2) determine how arthropod diversity and community composition varies between these plant species and various arthropod sampling techniques. Additionally, this study is intended to help the University of Hawai‘i at Hilo’s Office of Maunakea Management (OMKM) fulfill its regulatory need for arthropod inventories, monitoring, and research by demonstrating the use of limited empirical data to develop an alternative, targeted sampling approach that uses species accumulation curves to offset the logistic and taxonomic challenges of arthropod sampling and diversity estimates. Between July and November 2015, we collected over 13,000 arthropods within the University of Hawai‘i (UH) Management Areas and Maunakea Forest Reserve in the subalpine region of the Maunakea Volcano on Hawai‘i Island. For our data analyses, we used R version 3.3.1 (R Development Core Team 2015) for statistical analyses to compare arthropod diversity and community composition between plant species and sampling techniques. We used EstimateS version 9 (Colwell 2013) to create species accumulation curves to determine the sample size necessary to detect the total estimated arthropod diversity associated with C. oahuense, G. cuneatum; and S. chrysophylla. The results of this study will ultimately increase knowledge and awareness of Hawaiian arthropods and their ecological interactions, and help the OMKM and other land management entities minimize the cost and effort required to conserve native arthropods on Maunakea.
Assessment of light quality, variability, and seedling presence in Hawaiian lowland wet forests
(2015) Rosam, Jodie Ray; Ostertag, Rebecca; Tropical Conservation Biology & Environmental Science
Hawaiian lowland wet forest (HLWF) plant species are light-limited, yet no information exists on how the understory light varies in relation to species invasion, or if patterns of seedling regeneration and light are linked. I measured the red-to-far-red ratio (R:FR) of light to assess light quality and quantified diurnal variability in three forest types: native-dominated, partially-invaded, and fully invaded by strawberry guava (Psidium cattleianum). I asked: (1) how does understory light quality vary relative to invasion? (2) Are there differences in light quality moving vertically among forest types? (3) Are patterns of seedling regeneration and understory light related? Native-dominated forests had the greatest light quality (highest R:FR), and Psidium cattleianum-dominated forests had the lowest. While I predicted that native seedlings would prefer high-quality light sites, all seedlings preferred medium quality environments. In invaded HLWF, native seedling regeneration is hindered, and restoration efforts should focus on non-native understory removal.
Behavior, infestation, and molecular characterization of Cryptophlebia spp. (Lepidoptera: Tortricidae) associated with macadamia nut in Hawai'i
(2023-12) de Rocquigny, Nathalie Brigitte Marie; Arancon, Norman Q.; Tropical Conservation Biology & Environmental Science
CAN COMPOST FROM A NITROGEN-FIXING TREE, FALCATARIA MOLUCCANA, REPLACE CHEMICAL FERTILIZER AND STORE CARBON IN AGRICULTURAL SYSTEMS?
(2019-05) Norton, Joanna M.; Ostertag, Rebecca; Tropical Conservation Biology & Environmental Science
The challenges of food production, invasive species control, and climate change are intersecting, as they all stem from our ongoing use of land and energy on a global scale. In East Hawai‘i, two problems involving these issues are reflective of global trends. First, an expansion of agriculture is needed here, yet upland agricultural tracts are typically troubled by inherent low fertility, physically degraded and depleted of soil carbon from tillage, and require fertilizer inputs that are environmentally costly. Second, the invasive, nitrogen-fixing tree Falcataria moluccana (albizia) is dominating landscapes and altering ecosystems with rapid-cycling carbon and nitrogen inputs. These two problems are predicted to intensify with climate change, as growing conditions in each region shift and higher temperatures and carbon dioxide levels favor fast-growing, N-fixing species. Yet each of these problems could hold a remedy for the other, using practices described in the new field of climate-smart agriculture (CSA). Hawai‘i Island presents a unique opportunity to test whether or not accumulated nutrients from F. moluccana growth can benefit agricultural systems lacking in fertility, due to the intensity and grave consequences of the F. moluccana invasion, as well as the underutilization of agricultural land and lack of food self-sufficiency in Hawai‘i. This study examined whether compost from F. moluccana can replace chemical fertilizer and store carbon in agricultural lands in East Hawai‘i. Trials were conducted over one growing season and included two crops, Zea mays (corn) and Manihot esculenta (cassava), and 4 replicates across a spectrum of East Hawai‘i farmland sites representative of varying soil conditions and land use history. Treatments included a control, a typical application of chemical fertilizer (1N nitrogen applied), two levels of F. moluccana compost (1N and 2N levels of nitrogen applied), and two levels of combinations of chemical fertilizer and compost (1N and 2N). Harvest yield results showed that the F. moluccana compost was not an adequate replacement for chemical fertilizer in the corn crops. In contrast, F. moluccana compost produced cassava yields equal to chemical fertilizer, and economic and carbon costs were also similar across treatments. Variation among locations and within locations was larger than variation due to treatment in the cassava trial, but results suggest that the compost application was more effective on more degraded farm sites. Economic and carbon costs associated with the chemical fertilizer and F. moluccana compost applications were generally not different across treatments, and a partial analysis of carbon gained or lost was also similar across treatments. The results of these field trials show that CSA using F. moluccana compost is a viable alternative to chemical fertilizer, when the site is in need of organic matter (OM), and when the crop has favorable characteristics (long-season, rooting, and/or able to grow in low fertility areas). This research was designed and completed with the partnership of invasive species managers and farmers to maximize the usefulness of the research to the local community.
Characterization of Queensland Longhorn Beetle (Acalolepta aesthetica Olliff) Distribution, Host Selection Preference, and Environmental Correlations in Puna District, Hawai‘i County, Hawai‘i.
(2022-12) Miles, Blake Jonathan; Arancon, Norman Q.; Tropical Conservation Biology & Environmental Science
CHARACTERIZING THE LIFE HISTORY AND RECREATIONAL FISHERY OF NABETA, INIISTIUS PAVO, IN HAWAI`I
(2022-04) Masse, Richard Jay; Hopkins, Kevin D.; Tropical Conservation Biology & Environmental Science
Characterizing the pathogenicity profiles of Phytophthora colocasiae
(2016-08) Hiraide, Liliuokalani S.; Shintaku, Michael; Tropical Conservation Biology & Environmental Science
The most significant plant disease affecting taro is taro leaf blight (TLB), caused by Phytophthora colocasiae. A taro breeding program was established at the University of Hawai‘i to develop taro varieties with improved characteristics including resistance to TLB. The program was initiated by crossing taro varieties with resistance to TLB from Palau, Indonesia, Guam, with a Hawaiian variety, ‘Maui Lehua’ taro, known to be susceptible to TLB. A previous study used detached leaf disc assays to challenge new hybrid cultivars with P. colocasiae isolate HPA 1, which was originally isolated from Panaʻewa, Hawaiʻi. Many of the hybrids were resistant to this isolate and were classified as resistant to TLB. However, when these cultivars were subsequently challenged with P. colocasiae isolate HPE 3 from Pepeekeo, Hawai‘i (approximately 10 miles from Panaʻewa), some cultivars that were resistant to HPA 1 were susceptible to HPE 3. Further, a number of cultivars that were susceptible to the HPA 1 isolates were resistant to HPE 3. This current study aimed to determine whether the P. colocasiae populations in Panaʻewa and Pepeekeo are homogenous with regard to pathogenicity. This was done using a panel of seven taro cultivars selected in the previous study in addition to cultivar ‘Bun-Long’ which was used as a susceptible control collected from Waiakea Research Station and a taro field in Pepeekeo. The cultivars were separated into four categories: cultivars that were resistant to both HPA 1 and HPE 3, cultivars that were susceptible to both HPA 1 and HPE 3, cultivars that were resistant to the HPA 1, but susceptible to HPE 1, and lastly, cultivars that were resistant to HPE 3, but susceptible to HPA 1. The cultivars were challenged against 20 isolates of TLB, 8 from Panaʻewa and 12 from Pepeekeo. These isolates were designated HPA 2 – 9 and HPE 4 – 15, respectively. The original solates HPA 1 and HPE 3 were also analyzed in this study to evaluate whether changes occured in these cultures over time. We used the pathogenicity patterns of these isolates to group them into pathotypes, which were determined using two trials of detached leaf disc assays. In addition, the influence of some environmental factors on the leaf disc assay were analyzed by comparing disc assays from leaves of the same variety from nursery plantings in Panaʻewa, with field plantings from Pepeekeo. The influence of leaf size on disc assays was also evaluated by comparing the results of disc assays on large (older) and small (younger) leaves from a single plant. The first trial showed that the Panaʻewa and Pepeekeo P. colocasiae populations consisted of multiple pathotypes resolved using the panel of eight selected cultivars. The second trial, performed ~ 2 weeks after the start of trial 1, revealed a change in pathogenicity patterns in a few P. colocasiae isolates. While some P. colocasiae isolates displayed a surprising degree of plasticity over time with regard to pathogenicity, the plants used in this study were unaffected by varying cultivation practices, location, and leaf site. Based on the results of this study, I conclude that P. colocasiae field populations are heterogenous, and that P. colocasiae cultures can exhibit changes in pathogenicity profiles within 2 weeks.
Colorimetric determination of glyphosate in water using ozonolysis followed by spectrophotometric analysis of phosphate product with molybdenum blue reagent: a simple, fast and inexpensive assay of glyphosate.
(2022-12) Criscione, Rose; Platz, Matthew; Tropical Conservation Biology & Environmental Science
Community structure and demographic drivers of partial mortality in corals throughout the Papahānaumokuākea Marine National Monument.
(2019-05) Pascoe, Kailey Hoohokuokalani; Burns, John H.; Tropical Conservation Biology & Environmental Science
Understanding the association between coral community demographics and coral health is critical in the face of increasing environmental stressors driven by an ever-expanding human population. Within the last several decades, reefs around the globe have experienced substantial increases in levels of coral disease as well as large-scale outbreaks and mortality. Corals can experience partial mortality lesions because they are colonial organisms. A coral colony is constantly experiencing partial mortality lesion, fission and fusion. Corals exhibit highly variable levels of partial mortality, which is a useful indicator of overall coral health, thus it is important to identify drivers of this condition. This study examines monitoring data on coral health and disease from surveys (n= 4449) conducted throughout the Papahānaumokuākea Marine National Monument for the Reef Assessment and Monitoring Program (RAMP). Linear mixed-effects models were used to identify coral community demographic parameters that were associated with coral partial mortality. Significant variability in mean coral colony size, density, diversity, morphology, and partial mortality of corals was found among the sites in the NWHI. Mean coral size, density, and diversity decreased with increasing latitude. Mean coral partial mortality were also found to be statistically greater at sites in the high latitude atolls. Twelve morphologies in this study also exhibited differences in mean values of partial mortality. The results from the linear mixed-effects models showed coral partial mortality is predicted by the size of individual colonies (0.02±0.26(S.D.)), density (-0.33±0.07(S.D.)), species diversity (-0.03±0.01(S.D.)), and colony morphology. Colony size was positively correlated with partial mortality, whereas density and diversity showed slightly negative relationships with partial mortality. Columnar and mounding lobate morphologies exhibited the strongest effects with partial mortality. Understanding the relationship between coral community demographics and coral health can provide useful insight into how various coral populations may respond to increased levels of stress and disturbance. This research provides an example of how long-term monitoring data and hierarchical statistical modeling can provide information to help managers better understand coral health.

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