M.S. - Botany

Permanent URI for this collectionhttps://hdl.handle.net/10125/1954

Browse

Now showing 1 - 20 of 48

Flower biology of Hibiscus clayi (Koki‘o ‘ula): Determining the effects of inbreeding on seed set, germination, and growth on ex-situ plants
(University of Hawai'i at Manoa, 2025) Blum, Natalie Abao; Drake, Donald R.; Botany
Breeding systems describe the evolved reproductive strategies used by plants. They are the foundation for understanding the reproductive ecology of plant populations and their dependence on pollinator vectors. However, they are not always available to inform conservation procedures, owing to the lack of information about rare plant species. Hibiscus clayi (Malvaceae) is restricted to the island of Kauaʻi and is one of the four endemic species of Hibiscus found in Hawaiʻi. It is listed as endangered by the US Fish and Wildlife Service, assessed as critically endangered on the IUCN Red List of Threatened Species, and is at risk of extinction in the wild. To better inform methods for maintaining ex-situ collections and to enhance outplanting efforts, the breeding system of H. clayi needs to be explored. The objectives for this study were to experimentally investigate the breeding system of H. clayi by determining the degree of self-compatibility, and determine the effects of selfing, outcrossing within a population, and outcrossing between populations on fruit set, seed production, germination, seedling growth, and survivorship. To determine this, ex-situ collections of individuals originating from two different natural populations were used in experiments. Results showed that H. clayi is weakly self-compatible, producing roughly 29% as much fruit when selfed as when outcrossed. The outcrossing treatments had a significantly positive effect on fruit set and seeds per pollinated flower, but made no significant difference to seed count per fruit and mean seed mass. Fruit set when self-pollinated or left open to natural pollinators was low, so hand-pollination from a different individual is necessary to get the highest fruit set. Germination was high, >70% for all treatments, and no significant difference in performance was detected among treatments for seedling growth or survivorship. Outcrossing between populations slightly improved growth; therefore, long-term efforts to increase progeny should prioritize making controlled crosses when possible, to preserve allelic diversity and vigor of plants used in restoration.
Measures of genetic diversity across populations of the Hawaiian endemic ‘ākala, Rubus hawaiensis (Rosaceae)
(University of Hawai'i at Manoa, 2025) Michot, Rosalie; Morden, Clifford W.; Botany
Rubus hawaiensis (‘ākala), is a raspberry species endemic to the Hawaiian Islands that occursonly at higher elevations (>900 meters). Previous research on R. hawaiensis has focused on the species scale, carrying out phylogenetic research on the origin and hybridization patterns of the species. Little is known about genetic variability and population structure within the species, but it is distributed widely across the archipelago, and therefore likely has variation across the populations, either following geographical separation or environmental disparities. To characterize this variability, populations from Hawai‘i, Maui, and Kaua‘i were sampled and compared based on indices of genetic diversity and distances. Sequence information was gathered using multiplexed ISSR genotyping by sequencing (MIG-seq). Most notably, genetic diversity and distances were greatest among the three islands. There was also variation in the genetic composition of populations within each of the islands, especially on Hawai‘i Island. Physical distance between populations was not corelated with genetic distance as expected. Factors linked to elevation and habitat type seemed to be responsible for the patterns seen in genetic similarities across populations. Results suggest that factors other than distance and isolation impact the divergence among populations. Gene flow between distant populations with similar environmental conditions (soils, rainfall, elevation, etc.) may have been sufficient to maintain their genetic similarities.
Testing novel techniques to manage the invasive green alga Avrainvillea erecta (Berkeley) A.Gepp & E.S.Gepp on Oʻahu south shores
(University of Hawai'i at Manoa, 2025) Wheeler, Liv Wellington; Smith, Celia; Botany
Marine algal introductions threaten the biodiversity of Hawaiian reefs. With heavy shipping traffic occurring on the south shore of Oʻahu, plants are transported to near shore habitats. Coastal development and extreme use have impacted the native benthic communities. Psammophytic, or soft bottom habitats occur adjacent to Hawaiʻi fringing reefs, starting at about 15-18 m depth. Sea grass / algal meadows adjacent to coral reefs occupy as much as 50 % of benthos in Hawaiian shallow waters (<30 m). This study focuses on the meadows formed within these habitats. A newly introduced species of green alga called Avrainvillea erecta has been establishing and spreading in these meadows. It is the goal of this research to monitor the growth and spread of A. erecta and investigate management techniques to control its populations. Physical removal treatments were applied in 2020-2022. None of the removal treatments were able to significantly reduce the recovery of the plant. However, initial abundance positively influenced the number of plants that did recover in a 1m2 plot. Chemical management, using 10 ml of 3% hydrogen peroxide, were injected into plants at the Ānuenue Fisheries Research Center (AFRC) mesocosms and in situ off Kewalo Basin Oʻahu. While the mesocosm experiment did not result in a significant outcome, the in-situ experiment did result in a significant negative impact on plant densities. After analyzing these results and monitoring the spread of this plant across the main Hawaiian Islands, it is advised to categorize this plant as invasive. Areas frequented by boat anchors are at risk of transporting fragments of plants that can still be viable and propagate in new areas. Hawaiian shores that do not receive an annual storm surge should also be monitored. These quiet water locations specifically within Maui Nui complex are at high risk for invasion by A. erecta. Early detection via monitoring and rapid response appears to be the most critical action managers should consider.
Shedding a light on bryophyte distribution and facilitation: Exploring microhabitats and invertebrate interactions
(University of Hawai'i at Manoa, 2025) Jensen, Kassandra Leigh; Ticktin, Tamara B.; Botany
Bryophytes (mosses, liverworts, and hornworts) are underrepresented in conservation and restoration efforts, yet they play critical roles in maintaining ecosystem health. Globally, bryophytes have been shown to facilitate seed germination and seedling growth, as well as increase resources for invertebrates which may then pollinate plants or become food for other animals. This study is one part of a larger collaborative research project in Limahuli Stream in Hāʻena, Haleleʻa, Kauaʻi, which aims to understand the ecological foundations of Indigenous resource management, including the effects of management of riparian canopy cover on stream life. Specifically, we explored 1) how variation in daily mean light intensity affects bryophyte cover in the stream, and 2) if bryophytes are associated with the presence of invertebrates. We documented bryophyte identity and cover in four sites, using 8-22 transects per site and a total of 672 0.25x0.25 cm plots in order to capture the variation in bryophyte microhabitats. In total, 36 bryophyte species were recorded in the stream, including 23 mosses, 12 liverworts, and 1 hornwort. Bryophytes were found in 72.3% of all plots. The effect of mean daily light intensity on bryophyte cover varied across microhabitat types. In wet microhabitats (e.g., waterfall splash zones), bryophyte cover had a curvilinear relationship with increasing mean daily light intensity, from 0–12000 mean daily lux, then decreasing from 12000–15000 mean daily lux, but persisted even in areas with the highest light averages. The inverse relationship was seen in dry (e.g., dry rocks) and intermediate microhabitats (e.g., substrates at the water’s edge), where bryophyte cover declined from 0–9000 mean daily lux then increased from 9000–18000 mean daily lux. The effect of temperature on the probability of bryophyte presence showed a U-shaped pattern, and had minimal effect on bryophyte cover. Bryophytes forming dense, upright mats (“turfs”) were positively associated with mean daily light intensity. Across all microhabitat types except rock overhangs, the probability of invertebrate presence increased as a function of bryophyte cover. Additionally, mat-forming bryophytes were associated with invertebrate presence. These findings can guide restoration efforts, including outplanting decisions, canopy management, and reintroduction of bryophyte species to streams. As Hawai‘i faces threats from climate change and microhabitat loss, these insights are critical for addressing the urgent need to conserve biodiversity and restore degraded ecosystems.
REPRODUCTIVE ECOLOGY OF DUBAUTIA MENZIESII (THE HALEAKALĀ KŪPAOA) AND ITS INTERACTION WITH POLLINATORS IN HALEAKALĀ
(University of Hawai'i at Manoa, 2024) Guisado Chavez, Juan Francisco; Drake, Donald; Botany
Islands harbor a significant part of global biodiversity owing to their high level of species endemism, and they are also highly vulnerable to global change threats. Understanding plant reproduction is vital to conserve and restore island plants, ecosystems, and ensure stable population dynamics. Dubautia menziesii (Asteraceae) – The Haleakalā kūpaoa - is a common shrub endemic to the alpine and subalpine ecosystem of Haleakalā volcano on Maui. The purpose of this study is to: (i) characterize the breeding system of D. menziesii, (ii) identify its main pollinators, (iii) determine how plant isolation affects seed set and seed parasitism and (iv) estimate the abundance of D. menziesii and its flower resources in the habitat. For the breeding system, hand pollination treatments were performed in the field and seed set was analyzed. To identify pollinators, flower-visiting insects were observed on flowers in the field. To asses the role of isolation, seed set and parasitism were determined for individuals at varying distances from the nearest flowering neighbor. To estimate species abundance, the line-intercept method was used, and sampling plots were established. Dubautia menziesii is self-incompatible and requires outcrossing to set seeds (67% seed set for outcrossed flowers vs. 3% for manually self-pollinated flowers and bagged, unmanipulated flowers). The most frequent flower visitors were endemic Hylaeus bees (44%), and non-native honeybees (34%), followed by seed bugs Nysius spp. (15.9%). Isolation had no significant effect on parasitism rate at 2 sites (r=0.17, p=0.25; r=-0.06 p=0,71; respectively) nor for seed set (r=-0.28, p=0.055; r=- 0.27, p=0.1; respectively), probably due to visits by non-native honeybees, which forage over greater distances than Hylaeus. The high density of D. menziesii at high elevations on Haleakalā suggest that it plays an important role in maintaining insect populations in these communities.
Network-derived indicators of microbiome stability across a Hawaiian watershed
(University of Hawai'i at Manoa, 2024) Kajihara, Kacie Toshiko; Hynson, Nicole; Botany
Microbiome stability, the ability of microbiomes to rebound from or resist disturbances, is considered a coveted state, with the potential to inform the engineering of microbial consortia for medicine, agriculture, and ecosystem restoration. However, we lack an understanding of the fundamentals that stabilize microbiomes among hosts, environments, and habitats. Here, I leverage a ridge-to-reef microbial census of a Hawaiian watershed encompassing continental-scale environmental heterogeneity across a diverse array of hosts and habitats to address this knowledge gap. I show that inter-kingdom interactions between fungi and bacteria, putative negative interactions, and phylogenetic diversity universally describe stable microbiomes. These properties characterized microbiome stability at broad and more granular spatial scales, from the entire watershed to its constituent marine, freshwater, and terrestrial habitats, to individual sites along a steep terrestrial gradient. Counter to prior system-specific studies, network topological metrics and candidate keystone taxa did not predict stability. Notably, the most unstable networks described the most pristine sites including conservation areas with limited human influence, while stable networks described sites experiencing considerably more disturbance. This research illustrates unifying features of stable microbiome networks and calls into question whether stability should be an aspirational goal for microbiome engineering efforts.
E Hoʻokohukohu I Nā Limu O Hawaiʻi: Developing Methodologies For Limu Identification And Socio-Cultural Knowledge Enshrouded In The Nūpepa Hawaiʻi
(University of Hawaii at Manoa, 2022) Ornelas, Brianna; Smith, Celia; Botany
Despite the spiritual, social and nutritional uses, as well as the ecological value that native algae, or limu, have in Hawaiʻi, only 30 known modern species names (Linnaean binomials) are accepted as tied to the thousand-year-old Hawaiian names for the same plants. Past syntheses documented over 200 Hawaiian names of limu but those studies lack several levels of confirmation. Thus, despite the diversity of research on limu across molecular, taxonomic and ecological perspectives, very little work has focused on the deep reservoir of traditional knowledge. More specifically no studies have approached this topic via the recently published database of nūpepa from the last century. The goal of this research was to explore the content of the historic Hawaiian nūpepa, or newspapers, in the online Papakilo database for Hawaiian names of limu and other traditional limu knowledge. Because of the novelty of this project, new methods were created and tested to survey, organize, and analyze the vast collection of nūpepa information. Articles that were deemed relevant to the thesis questions were archived into a Google Suite database created specifically for this project. Out of the hundreds of articles that were screened in the Nūpepa, 82 were selected as being of interest, archived in the database and categorized into five groups based on content. Four articles were translated in depth that described limu inoa, locations, and uses. One particular limu inoa, limu lipuʻupuʻu is currently under review for a possible update. This project can help inform conservation efforts by making traditional knowledge more accessible, but also by bringing traditional names of limu back into use by numerous communities including traditional practitioners, anthropologists, conservationists, and scientists.
Exploring and applying symbioses between a Hawaiian endemic orchid and mycorrhizal partner for conservation
(University of Hawaii at Manoa, 2022) Chapin, Thomas K.; Hynson, Nicole A.; Botany
Orchids rely on associated orchid mycorrhizal fungi (OMF) from the earliest stages of development to provide vital nutrients and even carbon. This carbon dependence, termed mycoheterotrophy, can be variable over time and environmental conditions, with many orchids remaining partially mycoheterotrophic even once they produce leaves capable of photosynthesis. Due to the marked difference between photosynthetic C3 plant and fungal pathways of carbon acquisition, previous studies have used stable isotope signatures to estimate the percent of fungal-derived carbon, and thus the degree of mycoheterotrophy, of orchids. However, orchids associating with so-called rhizoctonia fungi (orders Cantharellales and Sebacinales) have shown carbon signatures similar to autotrophic plants, despite nitrogen isotopic signatures characteristic of mycoheterotrophy, spurring a hypothesized condition coined “cryptic mycoheterotrophy”. C and N isotopic analyses were performed on fungal hyphal pelotons (Ceratobasidium, order Cantharellales) from roots of the rhizoctonia-associated Hawaiian endemic orchid Anoectochilus sandvicensis from three bog sites at Ka‘ala Natural Area Reserve (KNAR), Oʻahu, Hawaiʻi, alongside leaves of the orchid and surrounding autotrophic reference plants. Previous research shows that the adult Hawaiian orchid Anoectochilus sandvicensis engages in unexpected symbiotic specificity, associating with only three operational taxonomic units of the genus Ceratobasidium throughout the Hawaiian archipelago. Cultures of one Ceratobasidium sp. from these Oʻahu bog sites were produced and employed to support the germination of Anoectochilus sandvicensis seeds collected from Volcanoes National Park, Hawaiʻi Island. Upon isotope analysis, fungal samples were found to be significantly enriched in 13C, though considerably less so than ectomycorrhizal or other saprotrophic fungi. Orchids had significantly higher 15N enrichment and nitrogen concentration values consistent with expectations for a food chain, due to accumulations of 15N-heavy compounds and digestion of N-rich fungal biomass. Additionally, the presence of the fungal partner significantly increased seed germination rates, particularly on oatmeal agar media and under 14hr light/10hr dark conditions. Additionally, data shows the compatibility of A. sandvicensis seeds with a fungal operational taxonomic unit previously undetected on the originating island. However, as previously observed in other studies, failure to swiftly advance into higher stages of seed development suggests that this close mycorrhizal relative initiates germination but does not support later seedling growth. These data support prior findings of cryptic mycoheterotrophy of this species, provide a clearer picture of rhizoctonia isotopic signatures, and offer insight for future OMF culturing and symbiotic germination of these and other orchid species.
Insights on the distribution of the endemic Hawaiian fern genus Adenophorus Gaudich. (Polypodiaceae) on the island of Oʻahu, Hawaiʻi
(University of Hawaii at Manoa, 2021) Thomas, Miles Kealoha; Ticktin, Tamara; Botany
Epiphytes, plants that grow on other plants, are conspicuous members of manyecosystems around the globe but are most pronounced in humid forests. In tropical regions such as Hawaiʻi, upland wet forests sustain diverse communities of epiphytic vegetation, mainly consisting of bryophytes and ferns. Of the epiphytic ferns, the endemic genus Adenophorus Gaudich. (Polypodiaceae) is the most species-rich and represents a considerable amount of the biomass of Hawaiian epiphytic communities. However, little is known about the ecology and conservation status of this genus. This study assessed the distribution, abundance, and conservation status of Adenophorus species on the island of Oʻahu and identified some of the factors affecting it. I carried out surveys on transects along eight ridges of the Koʻolau mountains as well as in the Kaʻala Natural Area Reserve and sampled epiphytes on a total of 242 trees. Adenophorus abundance overall increased at higher elevations, although elevational patterns differed between species. Adenophorus oahuensis and A. haalilioanus distributions appear to be limited by elevation, the former at low elevations and the latter at higher elevations. Adenophorus abundance increased with bryophytes cover, and bryophytes appear to be important in the establishment of the gametophyte stage of these ferns. Adenophorus haalilioanus may exhibit host bias, but further studies are needed to confirm this. Several species of Adenophorus may be experiencing population declines (i.e., A. oahuensis, A. tripinnatifidus, and A. haalilioanus), a result of habitat degradation as well as shifts in precipitation likely due to climate change. Adenophorus abietinus shows great phenotypic variability and may warrant further investigation of two distinct varieties, one of which is mostly found at higher elevations near the Koʻolau summit ridge and may also be susceptible to perturbation by climatic changes in the near future if current trends of current climate change persist. These insights provide a strong foundation for the future conservation of these endemic ferns.
Unearthing the Role of Ectomycorrhizal Fungi in Pine Invasions on Maui
(University of Hawaii at Manoa, 2021) Thompson, Leah; Hynson, Nicole A.; Botany
Pines are one of the most invasive trees in the world, invading with the aid of belowground ectomycorrhizal fungal mutualists. Pinus radiata is currently invading multiple parts of the Hawaiian Islands, including near the Haleakalā National Park on the island of Maui. While there are no pines or their associated ectomycorrhizal (EM) fungi that are native to Hawai‘i, previous studies have shown EM fungal species, especially suilloid species, associating with P. radiata up to 1000 m away from the original plantations. In order to predict areas on Maui that are susceptible to future pine invasions, we must understand how the distribution of EM fungi, specifically Suillus spp., varies across the landscape and how these invasive fungi affect pine seedling success. To do so, a bioassay experiment was performed in which P. radiata seeds were grown from soil collected at varying distances from the existing plantation at the Kula Forest Reserve. Pine seedling roots were visually analyzed for percent colonization of EM fungi, weighed, and sequenced for EM fungal community composition using Illumina amplicon sequencing. The community of EM fungi found 2000 m away from the plantation was significantly different than the community within and around the plantation, and largely comprised of Suillus spp. The percent colonization of bioassay roots by EM fungi increased with distance from the plantation and increased colonization was positively correlated with increased seedling biomass. With the aid of Suillus spp., P. radiata appears to have the symbiotic partners needed to aid in the dispersal and survivorship of seedling out into this landscape.
Chronicles of Deep Reef Flowers: A Phylogenetic Monograph of the Family Kallymeniaceae (Rhodophyta) Associated with the Mesophotic Coral Ecosystems of Hawai‘i
(University of Hawaii at Manoa, 2020) Cabrera, Feresa Corazon Padillo; Sherwood, Alison R.; Botany
Cryptic diversity, alternating life histories, ecological plasticity, and evolutionary lability of the few morphological characters available for identification of expanded red blades in the Family Kallymeniaceae have steered multiple studies to focus on a molecular-assisted alpha taxonomy (MAAT) approach to resolving their systematics and taxonomy. Among previous Hawaiian work is the 2010 Rhodophyta Biodiversity Survey of the Hawaiian Islands, which included several specimens of these expanded red blades, and an in-progress assessment of Hawaiian mesophotic algal communities. As part of the current effort to resolve the taxonomic placement of these expanded red blades, we conducted a molecular survey using multiple gene regions followed by floristic taxonomic treatments to address the taxonomic crisis so prevalent in the group. At least 300 specimens of expanded red blades were collected from both shallow and mesophotic depths to contribute to the establishment of a more comprehensive biodiversity catalog of Hawaiian marine algae. These specimens also provided an opportunity to examine a largely unexplored community at depths as great as 162 m. In Chapter 2, I examined stipitate red blades in Hawai‘i that we identified as Psaromenia and Meredithia, as models for investigating species delimitation in morphologically and molecularly diverse species. Our study resulted in the description of two new and presumed endemic Hawaiian species. In the subsequent supplementary chapter, I present the in-progress molecular survey that points to new species, new records and a number of range extensions for the expanded red blades of the Hawaiian Islands that still remain to be investigated in detail. The astounding species-level diversity unraveled and resolved in this study is prerequisite to investigating larger scale macroevolutionary patterns and highlights the importance of generating an accurate baseline dataset for future monitoring efforts.
Biogeography And Phylogenetics Of The Hawaiian Endemic Hibiscadelphus, Hau Kuahiwi (malvaceae)
(University of Hawaii at Manoa, 2020) Champion, Solomon Joshua; Morden, Clifford W.; Botany
The endemic Hawaiian flowering plant genus Hibiscadelphus was described by Joseph F. Rock based on two species found on Hawaii island and one species from Maui in 1911. In the years since, five additional species have been described, one from Hawaii island, two from Kauai, and one each from Lanai and Maui. In April 2012, A new species was discovered with a small remote population of ca. 99 mature individuals, the genus as whole is critically endangered. It had been proposed that the island colonization history of species in the genus followed the “Progression Rule”, a well-documented pattern in many Hawaiian taxa of progressive colonization from the older to younger islands, as new islands emerged from the sea. However, no molecular phylogeny has been published that tests this hypothesis for Hibiscadelphus. It is the purpose of this work to generate a phylogenetic hypothesis of Hibiscadelphus and its relationship to other genera of the Malvaceae based on chloroplast and nuclear DNA sequenced from a combination of samples from living plants, herbarium specimens, and accessions from the Hawaiian Plant DNA Library. DNA sequences were examined by both Bayesian and Maximum Likelihood approaches for phylogenetic reconstruction. Further, a fossil and island age calibrated BEAST analysis was performed with a Relaxed Log Normal molecular clock to estimate lineage divergence timing within the Hawaiian archipelago. The molecular clock estimate corroborates generally accepted dates for island ages and supports the hypothesis of the Hibiscadelphus radiation following the Progression Rule. The resulting phylogenies also indicate Hibiscadelphus as a monophyletic clade that is nested within the African Hibiscus section Calyphylli, from which they appear to have diverged approximately 10 mya. These results indicate the relationship of Hibiscus and Hibiscadelphus is paraphyletic and Hibiscadelphus should be reclassified within Hibiscus. This insight further suggests that there were five independent colonization events of Hibiscus to the Hawaiian Islands.
Restoration of Hawaiian Tropical Dry Forests: A Biocultural Approach
(University of Hawaii at Manoa, 2020) Sato, Aimee You; Ticktin, Tamara; Botany
Worldwide, tropical dry forests are among the most endangered of all tropical forest ecosystems, and tropical dry forests once represented the greatest species diversity among forest types in Hawaiʻi. Current research shows that the extent of native tropical dry forest cover in Hawaiʻi may be as low as 1% of its original cover, with 45% of the tropical dry forest plant species at risk of endangerment. Despite the historical and current relationship of these forests with the wao kanaka (lower elevation human settlement zones), there has been little evaluation on the social-ecological outcomes of a biocultural approach to tropical dry forest restoration. Two forest restoration projects located within Kaʻūpūlehu and Auwahi, have excluded ungulates and removed alien plant species, and have used biocultural approaches to restoration. Drawing on these two sites as case-studies, this thesis discusses the motivations for, and components of a biocultural approach, provides a measure of the ecological success using a case-study of biocultural restoration at Kaʻūpūlehu, and includes an assessment on the status of tropical dry forest restoration projects across Hawaiʻi. This multidisciplinary study shows that the ecological success of the forest is directly interlinked with the social benefits of restoration, and I recommend that conservation and restoration efforts in Hawaiʻi should foster and recognize the continued relationship between the kaiaulu (human community) and kaiaola (ecosystem) of tropical dry forests.
An ecological comparison of turf algae between two sites on West Maui that differ in anthropogenic impacts
(University of Hawaii at Manoa, 2019) BROWN, DONNA L.; Smith, Celia; Botany
Kahekili Beach, on the northwest coast of Maui, Hawaiʻi has experienced multiple blooms of native and non-native algae over the past 30 years. These blooms have been associated with run-off from agriculture, coastal development, golf courses, and the Lahaina Wastewater Reclamation Facility injection wells which are now known as the source for substantial wastewater delivery to the coast. Multiple studies have examined the macro-algae, fish and invertebrate communities associated with the wastewater seeps in the nearshore water at Kahekili. However, the turf algae community has never been characterized. Turfs are a functional group made up of small multi-species assemblages of algae that are hard to identify in the field. They are important as a major source of primary production and they can also trap sediments, smother corals and compete with other benthic species for space. For this study, plugs with turf algae were taken from dead Porites spp. coral heads at Kahekili Beach and Olowalu as a comparison site with relatively oligotrophic water. Plugs were examined for turf height, sediment load, percent cover and identification to the lowest possible taxon. Herbivore fish data were obtained from the State of Hawaiʻi Division of Aquatic Resources to assess whether herbivore biomass would influence differences in the turf community between sites. At both sites turf height was positively correlated with higher sediment loads, however at Kahekili, turf was taller near-shore at the seep area compared to Olowalu, where turf was higher in deeper water off shore. Olowalu had higher species richness and near the seeps at Kahekili, many of the plugs had only cyanobacteria. Herbivore biomass for grazers and browsers was similar at both sites but scraper biomass was higher at Kahekili. These results indicated that the submarine groundwater coming from the LWRF is impacting the turf community at Kahekili by reducing species richness, promoting growth of cyanobacteria, and allowing turf to grow taller and trap more sediment.
Foliar fungal diversity related to Myrtle rust (Austropuccinia psidii) antagonism and its implications for pathogen resistance in the endangered Hawaiian Nioi (Eugenia koolauensis)
(University of Hawaii at Manoa, 2019) Chock, Mason Kamalani; Amend, Anthony S.; Botany
An introduced fungal rust pathogen, Austropuccinia psidii, is a primary component contributing to the decline of the critically endangered Hawaiian Eugenia tree (Eugenia koolauensis). Once common on the islands of Oʻahu and Molokaʻi, E. koolauensis is now limited to 11 populations with a total of ~99 mature individuals on the island of Oʻahu. Hundreds of asymptomatic fungal species live within the E. koolauensis leaf tissue, and recent studies imply the composition of these foliar fungal communities can affect the severity of pathogens such as A. psidii. Using molecular and culture-based methods, I characterized the foliar fungal community and introduced these diverse fungi in to microbiome of E. koolauensis leaves infected by A. psidii. By manipulating the composition of the leaf microbiome, via application of a leaf slurry and single isolate spore-slurries, I demonstrated how increased fungal diversity promotes resistance to A. psidii in E. koolauensis. These results highlight the potential of harnessing native microbes to induce disease resistance within a conservation context.
Reproductive Ecology and Population Genetics of Hawaiian Wiliwili, Erythrina sandwicensis (Fabaceae).
(University of Hawaii at Manoa, 2018-08) Grave, Emily F.; Botany
Hawaiian dry forests are severely endangered with little habitat remaining and many threatened or endangered species. Wiliwili, or Erythrina sandwicensis (Fabaceae), is among the most iconic dry forest trees. This research focuses on the reproductive ecology, population genetics, and regeneration of wiliwili by addressing: 1) Who are the current flower visitors? 2) What is the effect of different pollination treatments on the number, size, and viability of wiliwili seeds and seedlings? 3) What is the genetic relationship among wiliwili populations? and 4) What is the regeneration status of populations on O‘ahu and Hawaiʻi islands? I found that all floral visitors were non-native species. Outcrossed pollination treatments produced significantly more fruit and seeds than any other treatment. Few seedlings and saplings were found in any population, and populations were genetically distinct across islands. Outplanting efforts can increase recruitment by enhancing the potential for outcrossing and increasing the number of seedlings and saplings.
Genetic Relationships and Ancestral Character State Reconstructions of Psychotria L. Sect. Straussia (a. Gray) Fosberg (Rubiaceae).
(University of Hawaii at Manoa, 2018-05) Serrano, Joshua K.; Botany
Taxonomic classifications based on morphology and molecular studies of members in Psychotria sect. Straussia have been problematic leaving a number of species identities’ in doubt. Also, previous phylogenetic studies showed that Psychotria hawaiiensis may represents multiple taxa currently circumscribed under a single species. To resolve the identity of the taxa currently included in this species two nuclear and two chloroplast markers were used and analyzed using Maximum Likelihood and Bayesian Inference. Additionally, two morphological characters were examined in BayesTraits to elucidate relationships among taxa. The molecular analyses reveal that P. hawaiiensis is polyphyletic and varieties hillebrandii and scoriacea are not closely related to variety hawaiiensis and they may represent distinct species. Variation in domatia size and leaf venation are consistent with this interpretation of P. hawaiiensis and its lack of monophyly, but future work should investigate their taxonomic value within this sect. Straussia. Nomenclatural changes that may be needed in the future include reducing P. hawaiiensis var. hawaiiensis to varietal rank of P. mariniana. In addition, recognizing P. hawaiiensis var. hillebrandii and var. scoriacea as separate distinct species. Also, many of the recognized taxa are not well differentiated suggesting that other methods such as next-generation sequencing (NGS) technique should be pursed to disentangle the relationships of these taxa.
Factors That Affect Natural Regeneration, Growth, And Survival Rates Of Threatened And Endangered Species In Dryland Forests In Hawai’i
(University of Hawaii at Manoa, 2018-05) Libby, Riko; Botany
From Phylogenetics To Host Plants: Molecular And Ecological Investigations Into The Native Urticaceae Of Hawai‘i
(University of Hawaii at Manoa, 2017-12) Bogner, Kari; Botany
The following study investigated the native Hawaiian Urticaceae in both an evolutionary and ecological context. First, the phylogenetic relationships of the native Urticaceae were determined using molecular DNA techniques. Second, the relationships between the native Urticaceae and an endemic Hawaiian specialist herbivore, Vanessa tameamea (Lepidoptera, Nymphalidae), were explored in order to assess variation among urticaceous species as host plants. The family Urticaceae has undergone several taxonomic revisions in the past two decades as a result of molecular phylogenetic studies, although little phylogenetic attention has been paid to the Urticaceae taxa native to Hawai‘i despite four species being federally endangered and the presence of two endemic genera. Overall, results from the phylogenetic analysis using Bayesian inference presented here revealed that taxonomic revisions to five of the seven nativerepresented genera are necessary based on polyphyletic and paraphyletic relationships to other genera. Further DNA analysis is suggested to elucidate species-level relationships for the native species of Pipturus and several species of Neraudia. The analysis produced a well-supported, monophyletic Hawaiian Urera/Touchardia clade, and it can be inferred that a single colonization event, as opposed to the previously hypothesized two colonization events, led to the current three extant species in this clade. Results from a no-choice bioassay experiment revealed that V. tameamea performed best on two native, but distantly related species, Urera glabra (tribe Urticeae) and Pipturus albidus (tribe Boehmerieae). Additionally, caterpillars from both O‘ahu populations recognized and readily ate the non-native C. obtusifolia, although caterpillars from Hawai‘i Island reared on this plant diet did not recognize C. obtusifolia as a food source and subsequently died within their first instar. No significant correlations were found between putative defense or nutritive leaf traits and the metrics of performance. Thus, it remains unclear what factors underlie variation among plant species in suitability as host plants for V. tameamea. The bioassay experiment highlights the complex relationships between a herbivore and its host plants.
Phenological Patterns of Endemic Hawaiian Angiosperms
(University of Hawaii at Manoa, 2017-08) Jones, Casey A.; Botany
Studies in plant phenology have provided some of the best evidence of ecological responses to recent climate change. Many phenological studies have used herbarium specimen records for analyses. Phenology studies using herbarium records were reviewed in order to summarize approaches, applications, and validations to date. The lack of studies investigating tropical phenology was addressed by analyzing herbarium specimens from the Hawaiian Islands. The flowering and fruiting phenologies of 51 endemic Hawaiian angiosperms were analyzed using herbarium records from 1837-2015. Results indicated that 75% of these species have yearly flowering patterns. Species from temperate ancestral origins likely evolved to flower outside of spring and summer months, possibly to synchronize fruiting to the onset of the wet season. Shifts in flowering over the last century were associated with both temperature and rainfall. This study demonstrated that herbarium records can be a valuable resource for understanding the phenology of tropical plants.

Browse

Recent Submissions