Ph.D. - Botany

Permanent URI for this collectionhttps://hdl.handle.net/10125/8820

Browse

Now showing 1 - 20 of 70

Population genetic forestry and phylogenomics of Hawaiian sandalwoods
(University of Hawai'i at Manoa, 2025) Champion, Solomon; Morden, Clifford; Botany
Hawaiian Sandalwoods are a highly threatened group of trees. Historically, ‘iliahi orsandalwood have been some of the most intensively harvested forest products in the Hawaiʻi Islands. This harvest has left many to suspect sandalwood forests are extirpated in Hawaii. Remnant populations of sandalwood forests across the state have now been sampled and analyzed to determine population structure of this once ubiquitous forest type. Genotyping of distinct populations has been undertaken here to better elucidate the population structure of ‘iliahi. Finally, in addition to genetic sampling this study also includes the collection and analysis of heartwood tissue for select populations to assess the content and variability of the aromatic component, santalol.
Neotropical epiphytic orchids, rare Hawaiian trees, and experimental translocation: A plant conservation florilegium
(University of Hawai'i at Manoa, 2025) Douglas, Julia; Ticktin, Tamara; Botany
Plant conservation is the science and practice of perpetuating species and the ecosystems in which they are embedded through sustainable management. In the Anthropocene, plant extinction rates have escalated due to climate change and habitat loss, and effective human stewardship of plant species is vital. Translocation (syn. reintroduction) is the planting of propagules to augment populations in decline, re-establish extirpated populations, or mobilize species to novel habitat. Translocation efforts have increased worldwide, yet without a priori experimental design, environmental determinants of success remain unknown. Furthermore, ~32% of terrestrial ecosystems are governed by Indigenous people and local communities (IPLC), yet the intersections between translocation science and IPCL management are largely unacknowledged. To develop translocation methods in collaboration with local communities and elucidate focal species’ habitat niche, I conducted two experimental translocations: ʻohe mauka (Polyscias bisattenuata), a rare endemic Hawaiian tree, and ye’ nagatx (Prosthechea karwinskii), a Mexican epiphytic orchid used in biocultural celebrations. I monitored the translocated populations for 4 years (P. bisattenuata) and 2 years (P. karwinskii) respectively and constructed mixed effects regression models to assess the relationship of abiotic and biotic habitat factors with translocation outcomes. ‘Ohe mauka four-year survival was 11.5% and growth had a positive relationship with site temperature; successful translocation sites were lower in elevation than the extant range, suggesting that remnant populations may not fully represent optimum habitat. Ye’ nagatx two-year survival was 28%, and initial propagule biomass and bryophyte cover had positive relationships with survival and growth; translocation holds potential to recover orchid material after traditional use and increase abundance of bioculturally-important epiphytic species. To further explore the microhabitat factors that influence epiphyte distributions, I conducted a survey of orchids in the canopy of the Osa Peninsula (Costa Rica). I found evidence of niche partitioning across canopy habitat quality gradients; variables that influenced epiphytic orchid density and richness included location within tree crown, host tree taxonomic identity, canopy openness, and surrounding cover of ferns. Together, this florilegium of studies demonstrates how knowledge of species-specific habitat requirements and biotic interactions are imperative to inform effective translocation methods. While human plant harvest is criticized as a threat to in situ populations, I demonstrate how sustainable use, celebration, translocation, and stewardship of species can form a holistic continuum of conservation practice.
Social and ecological dimensions of forest stewardship in Pacific islands
(University of Hawai'i at Manoa, 2025) Nerfa, Lauren; Ticktin, Tamara; Botany
Forests face loss and degradation globally, yet they are essential for human and planetary health, hence their conservation and restoration are imperative. Tropical forests, particularly on islands, host high levels of biodiversity and endemism, and experience multiple threats due to climate change, invasive species, and other anthropogenic drivers of change. Major research gaps on tropical island forest conservation and restoration include establishing a better understanding of how human dimensions are incorporated into forest conservation efforts; the most effective methods to manage non-native species; and the impacts of climate change. In this thesis, I addressed these gaps by examining social and ecological aspects of forest conservation and restoration (together called stewardship) in two Pacific Island archipelagos: the Hawaiian Islands, and the Southern Line Islands. The main question being asked is: what are the drivers and limitations that promote or hinder the success of conservation and restoration? I used a combination of document analysis, interviews, vegetation surveys, and comparisons to historic studies to address: 1) What is the range of types of organizations focusing on terrestrial ecosystem stewardship in Hawaiʻi and how do these organizations incorporate human dimensions into their approaches and discourse? 2) What underlying values drive restoration practitioners and how do they define restoration success? 3) What restoration techniques affect metrics of restoration success in Hawaiian mesic forests? 4) How is vegetation of currently uninhabited islands affected by land-use history and an extreme El-Niño Southern Oscillation (ENSO) event, and what does this mean for restoration in the context of climate change? I found that organizations in Hawaiʻi incorporated the human dimensions in diverse ways, with no clear trends with respect to organization type; that all organizations involved local communities; and that the majority of organizations included cultural aspects in stewardship. Restoration practitioners in Oʻahu’s Waiʻanae mountains were motivated by a passion to protect and restore the unique and imperiled species and ecosystems of Hawaiʻi. I found that some of their measures of success were achieved, including native species predominance in the midstory of the restoration sites. Removing non-native trees by total cutting or girdle treatments led to better metrics of restoration success than the selective cutting of trees, but removal of non-native species alone was not sufficient to support native species regeneration in the understory. Furthermore, time since initiation of restoration, out-planting density, and weeding frequency did not affect indicators of restoration success over the timeframe of the restored forests that were studied (4-14 years post-initiation of restoration). In the Southern Line Islands, changes in species richness were noted on all islands since the historic studies, with a reduction in species richness found for most islands due to the disappearance of some non-native species which had been cultivated previously. There was some evidence of drought post-ENSO, with implications for the plant communities facing climate change. Taken together, the findings provide a breadth of knowledge on social and ecological factors which can support effective terrestrial ecosystem stewardship in Pacific Islands and other similar tropical ecosystems.
Plant Invasions In Hawai‘i: Fire Risks And Grass Invasion Patterns
(University of Hawai'i at Manoa, 2024) Faccenda, Kevin; Daehler, Curtis; Botany
The Hawaiian islands have been deeply impacted by invasive species introduced over the past ~250 years since European colonization, with grasses playing an outsized role. Invasive grasses (Poaceae) now cover ~ ⅓ of the land of Hawai‘i, displacing native species, modifying habitat structures, and fueling fires. Concerningly, new grasses and other fire promoting species continue to be introduced to the Hawaiian islands leaving many data gaps. I developed a screening system to identify introduced plant species that are likely to increase wildfire risk. This tool uses a machine learning model to predict fire risk scores from traits obtained from literature and databases. The model revealed that just four variables can identify species categorized as higher fire risk by experts with 90% accuracy, while low risk species were identified with 79% accuracy. I then used the predictive model to screen > 140 recently naturalized plants in Hawaiʻi and identified species (6% of naturalizations in the last ~ 10 years) that are likely to pose a high fire risk and can be targeted for eradication or containment to reduce future wildfire risks. Grasses were prominent among these species. I then focused on studying grasses in Hawai‘i through a historic lens, aiming to see how the current grass flora came to be by examining the herbarium record, newspapers, agricultural literature, and floras going back to the 1800’s. I also conducted a taxonomic revision of the Hawaiian introduced grass flora looking for undocumented naturalized grasses. Significant grass imporations began slowly following the proliferation of cattle ranches after the 1840s, in search of “improved” pasture grasses suitable for high intensity grazing. The importation of foreign forage grasses accelerated dramatically in the early 1900s with the establishment of the Hawai‘i Agriculture Experiment Station (HAES) on O‘ahu by the United States government. The HAES imported seeds, trialed grasses in introduction gardens, and distributed seeds to ranchers across the islands. In total, 577 grasses were introduced post-1778, 158 of which were likely accidental introductions whereas 419 were deliberately imported. While importation of new grass species has stalled in recent decades, new accidental introductions continue to naturalize, with 30 newly naturalized grass species recorded between 2000 and 2023; some of these records were first recorded through my studies. Through this historical examination of grass naturalizations, I noticed that there is often a delay between when a species first appears in the herbarium record, and when it is identified and published. This is significant as herbarium specimens and published reports serve as primary sources for the study and management of biological invasions and delays in reporting can bias these data. The Hawaiian naturalized grasses were used as a case study to examine these delays among 269 species introduced after European colonization. There was an average delay of 27 years (median of 17 years) between the first naturalized herbarium specimen and its publication, and this delay has decreased among more recent naturalizations. Adding to this delay is the time needed for correct identification of specimens, which was an average of 18 years, but a median of 4 years, indicating most grasses are quickly identified but others take decades. Expanded investment in and support of taxonomic experts at biodiversity institutions is needed to reduce reporting delays for new naturalizations as these delays decrease the likelihood that populations will grow beyond what can be eradicated.
Illuminating the Hawaiian Mesophotic Red Blades: Genomic Insights Uncover Novel Biodiversity and Genomic Novelties in the Evolution of Rhodophyta Associated with the Hawaiian Mesophotic Ecosystems
(University of Hawai'i at Manoa, 2024) Cabrera, Feresa Corazon Padillo; Sherwood, Alison R.; Botany
Red algae, or Rhodophyta, play a central role in Hawaiian culture, ecology, and economy. Hawai‘i’s marine research community is deeply committed to scientific exploration, venturing into the lesser-explored twilight reefs known as Mesophotic Ecosystems (MEs), which range from 30 to 150 m in depth. Within these ecosystems, red blades extensively colonize the seafloor, spanning from the sunlit shallows to the light-limited mesophotic zones. Despite the critical roles played by red algae, their biodiversity and evolutionary history remain largely obscured, representing a significant gap in our understanding of Hawaiian marine ecosystems. In response, Chapter 1 of this dissertation undertakes a comprehensive exploration into the mesophotic red blades of Hawai‘i focusing on the orders Gigartinales and Halymeniales, employing a multifaceted approach that integrates morphology, phylogenetics, geography, and environmental factors. This study uncovers the Hawaiian mesophotic reefs as vibrant biodiversity hotspots with distinct floral communities, challenging prevailing assumptions about deep reef refugia and highlighting the vulnerability of these ecosystems. A landmark achievement is the description of four novel species within the genus Croisettea (C. kalaukapuae sp. nov., C. haukoaweo sp. nov., C. ohelouliuli sp. nov. and C. pakualapa sp. nov.), each given culturally resonant Hawaiian names, symbolizing their endemism and cultural significance. This taxonomic breakthrough not only enhances our understanding of red blade diversity thriving in the mesophotic depths but also serves as a critical step towards their conservation and preservation. Chapter 2 of the dissertation employs a taxogenomic approach, utilizing cutting-edge Next-Generation Sequencing (NGS) technologies, advanced computational models, and cyberinfrastructure to reconstruct complete organellar genomes of red blades. This endeavor includes phylogenomic and comparative genomic analyses. The culmination of this study is expressed through two manuscripts, identifying not only a new species (Amalthea mahilanii sp. nov.) but also introducing a new genus (Anunuuluaehu liula gen. et. sp. nov.) to our understanding of red blades. The insights gained shed light on the structural and evolutionary dynamics of red algal organelles, highlighting intriguing phenomena such as genome expansion and fungal-algal associations facilitated by introns. In Chapter 3 of this dissertation, I embarked on an exploratory survey to delve into the structural complexities within the mitochondrial genomes of the order Halymeniales. Contrary to the conventional belief of a 'master circle' structure for mitochondrial DNA in Rhodophyta, this investigation unveiled a diverse array of structures within the mitochondrial genomes of Halymeniales. These structures include circular, tripartite, stem-loop, and linear forms, marking a significant breakthrough in our understanding of mitogenomic diversity within Rhodophyta. This discovery also hints at intriguing possibilities, such as genetic recombination events that may have contributed to the emergence of subgenomic forms. In summary, this dissertation represents a significant leap forward in our understanding of Hawaiian red algae, uncovering new species, expanding genomic resources, and shedding light on the structural complexities of organelle genomes. These findings not only advance scientific knowledge but also have profound implications for the conservation and management of Hawai‘i’s marine ecosystems.
Mechanisms And Mitigation Of Soil Legacies Of Invasive Grasses
(University of Hawaii at Manoa, 2023) Singh, Manya; Daehler, Curtis C.; Botany
The grass-fire cycle can be accurately re-described as the human-grass-fire cycle, with the majority of invasive grass introductions being deliberate, and the majority of ignitions being anthropogenic in nature. With increased fire risk, and altered fire regimes favoring invasives, inhibiting natives, and depressing the resilience of native ecosystems, the stakes for restoring grass-invaded areas are higher than ever. Invasive grasses often grow in monocultures, outcompeting and suppressing other species, but even when removed, an abundance of research has demonstrated evidence of soil legacies that can hinder restoration efforts. Thus, there is a need to identify specific mechanism of soil legacies associated with invasive grasses that limit or inhibit restoration success, in order to translate that knowledge into mitigation strategies that better target these mechanisms. To begin, I gathered studies examining grasses for allelopathic abilities, to see if phylogenetically conserved allelochemicals, including benzoxazinoids, which are mostly Poaceae specific, points to allelopathy as a key soil legacy mechanism that contributes to disproportionate invasive success in the grass family. By narrowing the frame of the landmark allelopathy analysis by Zhang et al. (2020), I found support for the novel weapons hypothesis in invasive grasses; specifically, the allelopathic impact on native recipients, was more negative when the allelopathic species was a non-native grass, compared to when the allelopathic species was a native grass. Additionally, I found support for the phylogenetic distance hypothesis, supporting other research suggesting that allelochemical impacts depend on the phylogenetic distance of the target plant. I did not find support for the biotic resistance hypothesis, specifically that the allelopathic impact when the allelopathic species was a native grass was more negative on a non-native recipient, than a native recipient. Through this analysis, I showed evidence suggesting that land managers ought to consider testing for allelopathy, or considering allelopathy-informed restoration practices, when trying to restore grass-invaded areas. Next, in a field study at Camp Pālehua (Kapolei, O’ahu, Hawai’i) I compared soil characteristics and the soil microbial community between a Megathyrsus maximus invaded area, and an area that was formerly invaded by Megathyrsus maximus but had been restored by community partner Malama Learning Center 18 months prior to the comparison. The two sites shared a long history of grazing, climate and soil characteristics, and slope. While I could not rule out inherent differences between the sites that existed prior to the restoration, I sought to identify differences in soil characteristics and the soil microbial community that could be attributed, at least in part, to the restoration. While the restoration practice at the Malama Learning Center section was relatively successful, the site continued to require frequent hand-weeding, so I was particularly interested in evidence of a soil legacy in the soil microbial community, specifically any “hold-over” or “hold-out” taxa, that may be contributing to on-going re-emergence of grass species in the native ecosystem. I found a genus of fungi (Glomus) and bacteria (Candidatus Udaeobacter) were abundant at both sites and these genera have been identified in the literature as being associated with pastures, suggesting that, in the restoration site, these genera were hold-overs. This suggests that specific members of the soil microbial community could be contributing to on-going, long-lasting soil legacy effects, such that modifying the soil microbial community could mitigate some of these effects. In the third chapter, I conducted a greenhouse plant-soil feedback study, using a whole soil inoculum design, comparing germination, survival, and above/belowground growth in inoculum added soil to control soil. By using inoculum in less the 5% volume (w/w), I was able to isolate for the impact of the soil microbial community while holding soil characteristics and nutrients constant, to test for a soil microbial community mechanism for a soil legacy of an invasive grass (Megathyrsus maximus). In addition, I implemented a moderate drought treatment at 60% pot capacity to test for the impact of drought on any plant-soil feedback, since drought is expected to impact ecosystems in Hawai’i in the future. The native species used to test for feedback from the invasive grass microbial community was the endemic dry forest shrub Chenopodium oahuense. I found evidence that there was positive con-specific feedback (the grass benefited from its own soil microbial community) and negative hetero-specific feedback (negative impacts of the grass soil microbial community on the native), impacting primarily the belowground growth of both species, suggesting that the soil microbial community mediates belowground competition for space and nutrients. In addition, I found an interaction between the presence of the grass soil microbial community and drought that was associated with delayed germination of Chenopodium oahuense, suggesting that a soil legacy effect may contribute to phenological mismatch for native species as climate change progresses. In the fourth chapter, I conducted an experimental restoration at a separate Megathyrsus maximus invaded section of the Camp Pālehua property in Kapolei, O’ahu, Hawai’i using a soil amendment of activated carbon, alone and in combination with a locally sourced biowaste-based biochar fertilizer, to determine whether these amendments might mitigate the soil legacy mechanisms I had previously investigated. Two native species were used: Plumbago zeylanica and Dodonaea viscosa. I found that soil raking alone prior to planting improved the width of Plumbago zeylanica by 1 cm after 1 year. Raking had two effects that could have benefited plant growth: disruption of soil compaction, and suppression of the no-raking indicator fungi Bionectriaceae. In addition, I found that the height of Dodonaea viscosa increased 4 cm with 0.5 kg/m^2 of activated carbon added. Two potential explanations are the neutralization of any present allelochemicals, and the suppression of specific fungi which were indicators of the treatments lacking activated carbon, including Coniophora, which has been found in other studies examining the soil microbiome of restoration projects on former pastures. The hypothesis that after the initial suppression, the activated carbon treatment would create opportunity for the outplants to recruit new members to the soil microbial community, resulting in indicator species for the activated carbon level, was not supported. Overall, I was able to contribute evidence that allelopathic ability and the soil microbial community contribute to the soil legacies of invasive grasses, and in Megathyrsus maximus in Hawai’i, activated carbon can be used to suppress fungi and/or allelopathy to improve outcomes for some native plants, while raking alone can improve outcomes, potentially by disrupt soil compaction suppressing certain fungi. Activated carbon could be used in small scale-projects to create sustaining native ecosystems that can later be used for soil transplants or to provide soil inoculum in larger areas. Additionally, some of the identified fungi suppressed by activated carbon could be tested in isolation, or in different combinations for their impact on native plants.
Effects Of Climate Change And Eutrophication On Photosynthesis And Carbon-concentrating Mechanisms: Surprising Diversity Among Reef Algae
(University of Hawaii at Manoa, 2023) Kawachi, Migiwa Shimashita; Smith, Celia; Botany
Increased anthropogenic CO2 emission since the start of the Industrial Revolution has brought a changing climate and various threats to coastal ecosystems including ocean warming, ocean acidification (OA), and sea level rise. Coral reef ecosystems are especially vulnerable to the climate change, because ocean warming and acidification decrease calcification and increase bleaching in coral. In addition to these impacts of climate change, coastal ecosystems are already experiencing local anthropogenic impacts such as chronic eutrophication and continuing arrival of new invasive species. In Hawai‘i, large-scale blooms of both native and invasive macroalgae are often observed in the region with coastal eutrophication by land-based anthropogenic nutrient input. Predicting the effects of OA (increased CO2 concentration in the ocean) on algae is not straightforward because many algae are already equipped with carbon-concentrating mechanisms (CCMs) with which algae can increase their internal CO2 concentration for photosynthesis. Further, nutrient availability especially that of the macronutrient, nitrogen (N) could alter the operation of algal CCMs because CCMs involve specific, large proteins such as ribulose-1,5-biphosphate carboxylase-oxygenase (RUBISCO) and carbonic anhydrases (CA). This study experimentally investigated how OA and eutrophication, independently and synergistically, affect photosynthesis and CCMs in common Hawaiian reef algae. Algae can quickly change their maximum photosynthetic rates and CCMs when grown under elevated CO2 and N. Further, we found a surprising diversity among reef algae in how they react to elevated CO2 and N with their CCMs. The results of this study suggest that many Hawaiian algae will thrive under future climate change conditions, and OA and eutrophication will likely work in their favor, accelerating the phase shift from coral-dominated to macroalgal-dominated reefs in unpredictably faster paces and with players that are not easily predicted.
Ecohydrology of Macroalgae and Submarine Groundwater Discharge on Hawaiian Reefs
(University of Hawaii at Manoa, 2022) Gibson, Veronica Leigh; Smith, Celia; Botany
Interactions among ecological and hydrological processes have emerged as important areas of research as anthropogenic degradation of watersheds and climate change impact groundwater dependent ecosystems (GDE). Coastal reefs are examples of GDE in many tropical high islands; these reefs are subject to significant fresh, nutrient-rich-groundwater which creates estuarine conditions on nearshore reefs. To better understand benthic community dynamics on submarine groundwater discharge (SGD) influenced reefs, benthic cover and biological drivers of community composition at three SGD-influenced sites were analyzed. Generally, nearshore SGD-influenced regions have higher macroalgal coverage than marine offshore regions. Two of the three study sites were dominated in the nearshore SGD-influenced region by two invasive species, while the third site was dominated by native turf and macroalgae. Benthic community analyses reveal that tolerance of hypo-osmotic conditions could strongly influence the dominance of invasive species in low salinity, higher nutrient SGD-influenced regions. The physiological trait that allows plants to respond to hypo-osmotic conditions such as SGD conditions is ability to adjust tissue water potential (TWP). To investigate SGD responses, I updated a method to measure TWP in macroalgae and applied this method to invasive macroalgae that span the SGD-gradient and more narrowly, oceanic distributed native species at Waiʻalae ʻIki. Additionally measured responses included photosynthesis, cellular anatomy, and nitrogen content of four species of Rhodophyta to the SGD-gradient at Waiʻalae ʻIki. Two invasive Rhodophyta exhibited strategies of invasive biology with measurable responses consistent with success under SGD conditions; native species responses remained elusive. Further, in controlled growth experiments, TWP responses tracked simulated SGD-conditions by one Chlorophyte and one Rhodophyte, not found at Waiʻalae ʻIki. Understanding the relationships between SGD and macroalgal physiological ecology is pivotal to protecting native macroalgal diversity and ecosystem function, and to mitigating the effects of anthropogenic watershed degradation and climate change on SGD-influenced nearshore reefs.
Social-ecological resilience of agroforests in Fiji
(University of Hawaii at Manoa, 2022) McGuigan, Ashley; Ticktin, Tamara; Botany
Global change, including climate and socioeconomic change, has major impacts on linked human and environmental health. In food systems, this precipitated the rise of industrialized agriculture and related increases in nutrition-related non-communicable diseases. Agroforestry has the potential to serve as a food production system that addresses issues of environmental degradation, food security, and nutrition. In Fiji, agroforests are a part of a larger social-ecological system that has also enabled Pacific Island people to be resilient to disasters and disturbances for centuries. However, knowledge about how these systems are adapting to global change and their capacity is for resilience in this changing context, remains incomplete. I address this knowledge gap by exploring the dynamics of agroforests and their capacity for resilience after a catastrophic Category 5 cyclone. Specifically, I used a combination of farmer interviews, agroforest vegetation surveys, and nutritional analyses in 50 agroforests across five districts in Fiji, pre-cyclone Winston, and 1 and 3 years post-cyclone to address: How did Cyclone Winston affect agroforest starch crop and cultivar richness? How did Cyclone Winton affect agroforest trees, and what traits and management practices increase resistance to damage? Does the diversity of ecological functional traits in agroforests predict their nutritional diversity? Starch crop richness was highly dynamic and largely resilient to the cyclone, but cultivar richness declined. Post cyclone tree survival was high across all agroforests (87.8%). Bigger trees experienced more damage than smaller trees, and survival increased as a function of increasing wood density. In addition, the purposeful management of trees in agroforests likely buffered them against damage and mortality. A novel application of functional diversity metrics showed that nutritional functional diversity increased as a function of ecological functional diversity, indicating that agroforests are able to provide important levels of ecological and nutritional functions in the same space. This interdisciplinary research outlines the importance of agroforests in Fiji and their contributions to food system resilience and nutritional security. Understanding how agroforests in social-ecological systems are adapting to current changes is critical to inform the global community on resilience to future disturbances.
Phylogenetic Affinities Among Sida Species And Allied Genera (malvaceae: Malveae), And Examination Of Sida Fallax Within The Hawaiian Islands And Throughout The Pacific
(University of Hawaii at Manoa, 2022) Pejhanmehr, Mersedeh; Morden, Clifford W.; Botany
Malveae has the greatest generic and species diversity of the three tribes of subfamily Malvoideae (Malvaceae) with approximately 70 genera and 1040 species. Within Malveae, Sida is one of the largest genera with over 100 species of mostly herbs and small shrubs with world-wide distribution. The generic circumscription of Sida is problematic. Previous genetic analysis with a limited representation of species and genera and one gene region internal transcribed spacer (ITS) indicated that Sida is polyphyletic with a core group of species forming a distinct clade, but many species more closely associated with other genera and clades. In addition, section classification of Sida is problematic and many of these sections are not monophyletic. A study was conducted to investigate these objectives: first characterize the relationships among Sida species; second, determine their relationship to other Malveae genera; third, examine how these associations compare to the section classification; and fourth, investigate the biogeography of species within Sida. To do this, phylogenetic analyses of an extensive sampling of Sida species and most Malveae genera based on nuclear (ITS) and chloroplast DNA (psbA–trnH, rpl16, ndhF and matK) markers were carried out. Sequences were compared using Bayesian phylogenetic analyses. The nuclear and plastid phylogenies indicated that Sida as currently recognized is polyphyletic. The main Sida clade is monophyletic and represents the true “Sida” and is sister to the monotypic genus Fryxellia. The main Sida clade consists of at least 66 species including the type species, S. rhombifolia. Evidence indicates that Sida is largely of central and south American origins which is the center of diversity of the genus. There are at least 18 species currently classified as Sida that were not within the main Sida clade and should be revaluated. The previously identified section alliances are not consistent with the phylogeny and are in need of reevaluation based on morphological and phylogenetic grounds. Sida fallax Walp. (`ilima) (Malveae; Malvoideae; Malvaceae) is native to the Pacific area and is extensively distributed throughout this region. It is noteworthy that Sida fallax is the most widespread and variable taxon of Malvaceae in Hawaiian Islands and it occurs with diverse morphological forms and in different habitats from Hawaii Island to Midway Atoll. There are two extreme ecological forms of S. fallax with many intermediate morphological types between them in the Hawaiian Islands. A low elevation ecotype that is a sprawling, or prostrate shrubs with densely pubescent leaves that occurs along beaches and in dry, coastal shrublands. Sida fallax from other Pacific locations exhibit this form only. In contrast, the mountain ecotype is an erect shrub up to 2 m tall with glabrous leaves that is found in upland communities and mesic forest sites. The range of morphological and ecological diversity in Sida fallax suggest that this species requires further biosystematics investigation. Phylogenetic and population studies were carried out on S. fallax. The purpose of the phylogenetic study was two-fold. The first objective was to explore the genetic diversity among S. fallax populations throughout its native range in the Pacific region. The diversity in habitat and its wide distribution throughout the Pacific regions calls into question whether S. fallax is a single species or potentially multiple cryptic species. The second objective was to investigate the origin of S. fallax. To do this, populations of Sida fallax throughout Hawaiian Islands and different parts of Pacific region were collected. Bayesian phylogenetic analyses based on nuclear [(ITS) and external transcribed spacer (ETS)] and chloroplast regions (psbA–trnH) were carried out. The nuclear and plastid phylogenies of this study clearly demonstrated that Sida fallax is a single species throughout the Pacific region and the different forms of Hawaiian S. fallax are not genetically distinct at the sequence level. Although the pattern of dispersal of S. fallax is not clear, it is evident that an American origin is most likely. The population study objective was to investigate the genetic variation within and among populations from the various habitats and geographic locations throughout the Hawaiian range of S. fallax. To do this, populations were collected from six of the main Hawaiian Islands (Kauaʻi, Oʻahu, Maui, Molokaʻi, Lānaʻi, and Hawaiʻi) and Nihoa in the Northwestern Hawaiian Islands. DNA samples of 124 samples from 26 populations were selected for Multiplexed ISSR genotyping by sequencing (MIG-seq) to detect single nucleotide polymorphisms (SNP). Genetic differences among individuals and populations from across the range of habitat and locations of S. fallax in the Hawaiian Islands were evaluated using PCO analyses. The relationship of FST with the geographical distance between the populations was assessed using Mantel test. The Mantel test identified a significant positive correlation between genetic and geographic distances among S. fallax populations. Three main island groupings were evident in PCO graphs: 1) Oʻahu, Kauaʻi and Nihoa; 2) Maui, Molokaʻi, and Lānaʻi (collectively referred to as Maui Nui); 3) Hawaiʻi Island. Populations from each island grouping intersect at the center of the graph, the zone of intersection (ZOI), suggesting gene flow still exists among them. There was a trend of coastal/beach populations occurring more predominantly near the ZOI, and the mountain/inland or most isolated populations being more away from the ZOI. Overall, populations on a single island were more closely related to each other and to populations on islands within their respective groups than they were to populations on other islands. Because long-distance seed dispersal via ocean currents is more probable for beach ecotype populations, the beach ecotype populations of all islands showed somewhat closer relationships to each other than to mountain ecotype populations and provided some continuity among all the island groups. The overall genetic relationships among islands were to a large extent predictive based on island position within the chain, and, to a lesser extent, within island topography.
High elevation Hawaiian plant communities: implications for conservation under climate change
(University of Hawaii at Manoa, 2021) Ainsworth, Alison; Drake, Donald R.; Botany
Globally, subalpine, and alpine plant communities are receiving increasing attention due to disproportionate rapid warming at high altitudes and the resultant shrinking habitat leaving high-altitude specialists with less habitat and nowhere to migrate. Plant communities on tropical high islands, such as the Hawaiian Islands, are predicted to experience rapid climate change, and if increased temperature and/or drought exceed plant species’ current tolerances, species that are unable to adapt or shift ranges, risk extinction. While extensive climate modeling is underway in Hawaiʻi, few studies have assessed the potential impacts of climate change on high elevation vegetation. To address this knowledge gap, I first quantified habitat specialization for 170 plant species using species co-occurrence data from over one thousand plots to rank species’ realized habitat niche breadth using the Jaccard index. This indirect method of estimating species’ potential climatic flexibility uses increasingly available large plant community data sets with output rankings which represent species’ realized habitat niches. The distribution of species along this continuum differed by species’ biogeographic origin, with endemic plant species ranked on the specialist end and non-native plant species ranked on the generalist end. Habitat specialization rankings also differed by number of habitat moisture types, minimum elevation, number of Hawaiian Islands, and life form. Volcanic mountains in Hawaiʻi have distinct treeline ecotones driven by trade wind inversion. During the past fifty years, periods of increased temperature and drought associated with increasingly frequent cloud inversion events have occurred, but little is known about how these climatic changes have influenced treeline vegetation. Vegetation data from 225 plots spanning treelines (1500-2500 m) on Haleakalā and Mauna Loa were used to categorize ecotonal plant communities. Treeline indicator species differ by moisture and temperature variables with common native species important for all types: wet forest (Cheirodendron and Metrosideros trees, ferns), subalpine woodland (Myoporum and Sophora trees), and subalpine shrubland (Vaccinium and Leptecophylla shrubs, native graminoids). The subalpine woodland contains the most habitat generalist indicator species, likely due to high non-native species richness. Moisture best explains the described patterns in plant community composition, with wet canopy evaporation, mean annual precipitation, and aridity index values differentiating between wet forest and subalpine communities. A wider extent of the subalpine zone (i.e., beyond treeline ecotone) was analyzed to further identify commonalities and differences between plant communities on Haleakalā and Mauna Loa volcanoes. I compared plant species richness, cover, and density data from 89 plots. A total of 138 plant species were recorded and over half of these species were non-native (56%) with the remainder being endemic (30%) and indigenous (14%). Gamma diversity differed between volcanoes with one-third found only on Haleakalā, one-third found only on Mauna Loa, and one-third shared. Species richness per plot differed from gamma diversity in that endemic species were more abundant than non-native species for both volcanoes indicating that while many non-natives are present, their populations remain patchy and not yet widespread. Non-native species richness was higher on Haleakalā than Mauna Loa. In general, the subalpine communities are characterized by patchy low-lying (<1 m) vegetation with lower cover on the younger drier site – Mauna Loa (36%) than on Haleakalā (56%). Community structure was largely consistent with the understory cover data, with endemic Vaccinium (>3500/ha) and indigenous Leptecophyllya (>2430/ha) shrubs dominant. I recommend continued monitoring of biotic communities and climate in this sensitive high elevation zone, additional physiological in situ studies for the few native matrix subalpine plant species, stricter non-native species biosecurity and sanitation protocols, wildfire prevention, and improved documentation of the effects of feral ungulates including their ongoing removal.
Understanding the potential for restoration through agroforestry in Hawaiʻi
(University of Hawaii at Manoa, 2021) Hastings, Zoe; Ticktin, Tamara; Botany
Agriculture is a major driver of global environmental change. Restorative practices like agroforestry, that integrate native and non-native, culturally important plants while mimicking the structure and function of native forests have the potential to increase biodiversity and ecosystem services of conventionally managed and fallow agricultural lands. However, what the potential is of restoring these lands using agroforestry and who is able to participate in agroforestry transitions remains a question. I focus on agroforestry transitions in Hawaiʻi, where a long history of Indigenous agroforestry and more recent interest in biocultural restoration provide an important context for understanding equitable pathways to agroforestry today. In the first chapter, I show how integrating co-production of knowledge with functional trait approaches to designing restoration and agroforestry research with local stakeholders can lead to more inclusive and scalable results. In the second chapter, I apply this approach to an experimental restoration that asks, 1) do initial measures of restoration success (i.e., understory composition, understory cover, and mid- and over-story survival) vary between treatments over the first two years, and if so, are these treatment effects mediated by other drivers, and 2) how does the ecological condition of the site compare to pre-restoration? Based on plant community metrics, the results show that non-native forests have a high potential for restoration through agroforestry, and this provides an important first step in documenting what non-native forest to agroforest transitions can look like. The third chapter is a state-wide study, in which I ask, what factors drive and/or restrain transitions to agroforestry, and who is able to participate? I found that agroforestry practitioners are motivated to restore ecosystems and reclaim sovereignty, not just by the direct or practical benefits of agroforestry. Practitioners’ values often conflict with the values of dominant funders, landowners, and other institutions, which produces unique obstacles. Access to off-site resources that are inequitably distributed often determines who can persist despite the obstacles. Taken together, the findings in this dissertation highlight the significant opportunity to restore conventionally managed and fallow agricultural lands through agroforestry and the need for structural change to ensure equitable access to the opportunity presented by these land use transitions.
A Biodiversity Informatics Approach To Preventing Invasions: Using A Whole Non-native Flora To Investigate Introduction Pathways And Methods For Invasion Tracking
(University of Hawaii at Manoa, 2021) Brock, Kelsey C.; Daehler, Curtis C.; Botany
Negative impacts from biological invasions continue to rise as non-native species spread around the globe. As the costs of controlling these species increases significantly after their establishment and spread, invasion biologists acknowledge that strategies to prevent invasions should be a key focus in addressing invasive species problems. However, numerous species may be introduced each year, making it difficult to prioritize would-be invaders among hundreds of other species. Thus, strategies that identify and regulate pathways for species introductions are needed to complement species-specific approaches. Furthermore, methods to track the rate at which new species establish and their fate after arrival are lacking, despite the need to assess risks from future invaders and evaluate the success of prevention strategies. To address these issues, I gathered data on the date of naturalization for the entire naturalized flora of the Hawaiian Islands alongside data on their origins, native climate type, taxonomy and likely reason for introduction (introduction pathway). By comparing rates of naturalization for each introduction pathway with changes in socioeconomic factors, I reveal that Hawaiʻi has received a diversity of plants from all over the world, and that the rate of ornamental plant naturalizations has risen dramatically since the mid-20th century, reflecting Hawaiʻi’s shift to a tourism-based economy from an agricultural one. I also show that, although many naturalized plants may currently exist in Hawaiʻi at lower elevations with warmer climates, a large proportion are native to climates similar to those found at higher elevations. This pattern is significant because Hawaiʻi’s remnant native-dominated ecosystems exist primarily at higher elevations, indicating that preventing non-natives from establishing in native ecosystems is crucial to conservation of native species. Additionally, the rate of spread between islands has increased since the mid-20th century, highlighting the need to prevent inter-island spread. To explore the pitfalls that arise when measuring rates of naturalization over time, I then focused on a relatively neglected factor that can bias analyses: time lags that accrue when processing data after their collection in the field. Using computer simulations and an analysis of a real-world case study of two independently collected datasets for the Hawaiian Islands, I illustrate how time lags interact with common data retrieval strategies to influence the interpretation of invasion trends. By doing so, I reveal that long lags due to insufficient field surveying can create the illusion of a sudden onset or exponential rise in naturalization rates, whereas lags in identification, reporting and compilation result in the deceptive appearance of an invasion slow down. I also show that harvesting data from already-compiled resources published by experts may introduce a temporal sampling bias because such works are sporadically produced, thereby introducing an additional lag between reporting and data compilation. Lastly, I investigate a strategy for tracking species after their arrival by using Hawaiʻi’s naturalized species checklist as a starting point and applying a well-recognized framework that categorizes the phase of a non-native species’ establishment along the introduction–invasion continuum. After finding that data deficiencies prevent hundreds of species from being categorized within the framework, I show that data from the Hawaiʻi-Pacific Weed Risk Assessment can be reappropriated to predict whether a data-deficient species will progress along the continuum. Ultimately, I reveal that this predictive tool is a promising supplement to on-the-ground monitoring, especially when frequent field surveys are not feasible. Although globalization continues to facilitate numerous invasions, our ability to harness data and solve problems using biodiversity informatics is advancing rapidly. Here, I contribute to this progress by uncovering trends useful to policymakers and managers in invader-rich regions, while also offering guidance on how to improve methods used to measure those trends and track invasions.
The Use Of Arbuscular Mycorrhizal Fungi In The The Restoration Of Endemic And Indigenous Hawaiian Plants
(University of Hawaii at Manoa, 2020) Koko, Jerry; Hynson, Nicole A.; Botany
In Hawaii, it’s estimated that 31% of native flora is endangered due to habitat and pollinator loss, and competition from invasive species. There are widespread efforts to restore native Hawaiian plants and habitats by various organizations to mitigate this problem. These ecological restoration projects, however, often do not utilize arbuscular mycorrhizal (AM) fungi, although it is estimated that >90% of native Hawaiian plants form symbioses with them. AM fungi are a prevalent, widespread group which colonize an estimated 80% of all plant species in the world. AM fungi have been shown to benefit their host plants by increasing uptake of water and nutrients, as well as protecting against pathogens. Numerous studies have also shown their importance in ecological restoration projects outside of Hawaii. This dissertation focuses on the potential use of AM fungi in ecological restoration projects in Hawaii. I investigated the viability of AM fungal spores in 50-year-old soils collected from Hawaii Volcanoes National Park on the Island of Hawaii to inform the longevity and storage of AM fungal inoculum (Chapter 1). The viability of AM fungal spores was determined to be minimal, suggesting that 50 years is too long for storage of AM fungal inoculum. I also investigated the potential use of AM fungi and Moesziomyces aphidis, a foliar yeast, in decreasing the disease severity of Neoerysiphe galeopsidis infecting Phyllostegia kaalaensis, a critically-endangered mint native to the Waianae Mountain Range (Chapter 2). AM fungi, as well as M. aphidis and the combination of both are effective in decreasing the disease severity of N. galeopsidis infecting Phyllostegia kaalaensis, however only M. aphidis significantly so, indicating that the microbial symbionts could be used in lieu of fungicides in controlling this pathogen in the greenhouse and potentially in the wild. Finally, I sampled root tissue from 35 different native Hawaiian plants species commonly used in ecological restoration across 10 sites on the island of Oahu to detect for mycorrhizal occurrence (Chapter 3). I also calculated the percent root length colonization (PRLC) and investigated the potential effects of species and site on PRLC. Thirty-four of 35 (~97%) plant species were found to have mycorrhizal colonization, which exceeds a previous estimate of >90% of Hawaiian plants forming mycorrhizal symbioses. The presence or absence of AM fungi have been identified in 22 species of plants that were not surveyed previously. The PRLC of 5 species of plants was significantly affected by different site factors, such as mean annual precipitation and nutrient availability, that increase the root length of plants as well. Overall, these results suggest that the inoculation of AM fungi in the greenhouse should be considered in future ecological restoration projects in Hawaii.
Disentangling The Biocultural Roots Of Medicinal Plant Knowledge: Testing Ethnobotanical Hypotheses In Solomon Islands
(University of Hawaii at Manoa, 2020) Bond, Matthew; Gaoue, Orou G.; Botany
Ecological knowledge is fundamentally linked to the function, diversity, evolution, and stability of biological and cultural systems (also called biocultural systems) and the ecosystem services they provide. However, there is currently limited understanding of how ecological knowledge develops and is distributed among humans. In this dissertation, I assessed the medicinal plant knowledge, sociocultural demographics, and social network connections of 305 people in four subsistence villages in Solomon Islands. These data were used to test theories of how the distribution of medicinal plant knowledge is affected by plant availability, sociocultural demographic factors, and social network connectivity. The dissertation is divided into four chapters. First, I provide the first comprehensive review of availability theory in medicinal plants, and test whether recent research has fewer methodological limitations than older research. Second, I test how age and gender affect plant availability theory, which predicts that plants which are more available to people are more likely to be known and used, while examining synergistic effects between various predictors of plant use. Third, I provide the first test of how age, gender, sociality, education, outdoor exposure, income, and medical clinic use interact to affect medicinal plant knowledge using structural equation modeling. Finally, I use exponential random graph modeling to analyze medicinal knowledge sharing networks and provide the first test of how prestige and homophily affect network structure and teacher selection. Testing these theories enhances understanding of (1) which characteristics of people and cultures are associated with different kinds and amounts of medicinal plant knowledge (such as age, social status, social experience, and proximity to plants), and (2) which plant traits are associated with medicinal plant use (such as size, community diversity, and lifespan). Taken together, these results suggest applications to (1) identify which people and cultures are most likely to know plant species that have pharmaceutical potential for specific diseases (such as infections), (2) select plant species and communities that are most likely to have medicinal activity, and (3) conserve ecological knowledge more efficiently by understand how specific biological and sociocultural factors affect medicinal plant knowledge.
Abiotic And Biotic Factors Associated With Current And Long-term Native And Non-native Plant Cover Across An Invaded Hawaiian Landscape
(University of Hawaii at Manoa, 2020) hibit, joshua; Daehler, Curtis C.; Botany
Extended periods of disturbance and the introduction of non-native species pose major threats to native Hawaiian forests, many of which exist today as remnant patches, harboring native plant species that are on the brink of extinction. When native Hawaiian plant species are faced with competition from biogeographically cosmopolitan non-native species they are often at a disadvantage, especially in easily accessible areas and where high resource availability fuels the growth of invasive species, which can displace existing natives. However, relatively few datasets exist which can give insight into the long-term impacts of anthropogenic disturbance and species introductions on indigenous and endemic Hawaiian plant species across the myriad of abiotic site conditions that exist in the Hawaiian Islands. In addition, the importance of plant functional diversity, phylogenetic diversity, and biogeographical diversity for determining native resilience in invaded oceanic island forests has not been well established. To address this gap in knowledge I established fifty 400 m2 forest plots in the Waiʻanae and Koʻolau mountain ranges on Oʻahu, Hawaiʻi, and assessed current native and non-native plant cover trends in relation to measures of diversity and trait-mediated interactions of the constituent species in each plot. Thirty-two of these plots had also been previously surveyed, which allowed for an assessment of trends in endemic, indigenous, and non-native plant cover over time, and how these trends vary across abiotic gradients from dry to wet forest. The results of this study indicate that native Hawaiian forests may not be successfully regenerating and are being invaded by non-natives. Native and non-native plant cover values were determined by their respective diversity measures, as well as competition for light. invasion success was not related to overall trait dissimilarity, but there are likely additional traits which were not measured in this dissertation that influence competitive outcomes and/or niche filling between natives and non-natives. Non-natives exhibited a variety of successional strategies, reflecting the introduction history of tree species into the Hawaiian Islands for forestry purposes, as well as the intentional or accidental introduction histories of other herbaceous and woody species, and the diverse biogeographical origins from which these species arrived. Long-term trends showed that, as non-native plant richness and abundance has increased over time, native species in aggregate have concomitantly declined. However, this was largely the result of the loss of endemic species richness and cover, which were more susceptible than indigenous species to decline in the face of invasion, even where ungulates were excluded. Endemic species were more dependent on site conditions than indigenous species, which increased in overall cover over time, indicating that generalizations about natives as a single group may be misleading. Some of the indigenous species which increased in cover the most were early successional species, and may thus reflect disturbed or degraded conditions, rather than a trend toward recovery of natural native forests. These results suggest that an upscaling of active management efforts is needed to avoid further decline of native species, particularly endemics, and to stymie the tide of forest invasion by non-native species.
Phylogenetics And Evolution Of Oreogrammitis, Radiogrammitis And Themelium (polypodiaceae) And Population Genetics Of Hawaiian Endemic Oreogrammitis Hookeri And Adenophorus Tripinnatifidus
(University of Hawaii at Manoa, 2019) Sirimalwatta, Vithanage Nipuni Shalika; Morden, Clifford W.; Ranker, Thomas A.; Botany
Grammitids are a large monophyletic group of primarily epiphytic ferns in Polypodiaceae. Genera Oreogrammitis, Radiogrammitis and Themelium (ORT) formed a clade in grammitid phylogeny where three genera are polyphyletic in the ORT clade. A study was conducted to delineate the phylogenetic relationships of the ORT group by using intensive taxon sampling and with nine genetic markers from both nuclear and chloroplast genomes. Gene sequences were analyzed in maximum likelihood and Bayesian algorithms. Nuclear gene trees and nuclear and plastid gene trees were summarized to construct species trees under multi-species coalescent method in ASTRAL program. All the analyses with higher number of species and data revealed that the three genera are polyphyletic. Thus, taxonomic revisions are suggested. Oreogrammitis must be redefined to include Radiogrammitis and Themelium. Oreogrammitis hookeri is an endemic Hawaiian grammitid fern. It is one of the three Hawai‘i endemic Oreogrammitis species. Oreogrammitis hookeri can be found in all the major islands in Hawaiian archipelago whereas the other two species have limited distribution. Some populations of O. hookeri contain unique alleles and the species may have been undergoing incipient speciation or represent cryptic species complex. Current study was conducted to investigate the population structure of O. hookeri with populations sampled from all the major islands except Lanai. Double Digest Restriction Site Associated DNA sequencing (ddRADseq) technique was used to generate genomic data. Analysis of 176 loci in STRUCTURE program showed that there are two genotypes in O. hookeri. Populations collected from Kauaʻi and Mauna Loa, Hawai‘i is one genotype and Oʻahu and Kilauea, Hawai‘i is another genotype. Maui and Molokaʻi contain both genotypes. Incipient speciation or existence of cryptic species of O. hookeri can be ruled out because Maui-Molokaʻi genetic cluster contain both genotypes thus it supports the idea that individuals from all sampling localities are part of one interbreeding lineage. Genetic differences among populations could simply be due to random processes such as founder effects although localized adaptation cannot be ruled out. Genus Adenophorus is one of the two endemic fern genera in Hawai‘i. The genus consisted of ten species. Adenophorus tripinnatifidus is highly variable species. A population study done on A. tripinnatifidus showed low levels of interpopulational gene flow when compared to its conspecific, A. tamariscinus, species. The present study conducted to explore the genetic structure of A. tripinnatifidus. Samples collected from Kauaʻi, Maui and Molokaʻi. DNA samples of 35 samples from four populations were sequenced using ddRADseq technique. Hundred and forty-four loci were analyzed in STRUCTURE. Two genotypes were recovered. Kauaʻi populations are genetically distinct from Maui and Molokaʻi populations. Thus, it can be inferred that A. tripinnatifidus is undergoing incipient speciation.
Effect Of Wild-harvest On A Commercially Important Seaweed: A Case Study Of Mazzaella Laminarioides (Rodophyta, Gigartinaceae) In South-central, Chile
(University of Hawaii at Manoa, 2019) Lopez Vargas, Gioconda T.; Ticktin, Tamara; Botany
To characterize the uses of seaweed, and investigate the socio-economical and ecological impact of harvest form wild-stocks, I focused on a case-study of Mazzaella laminarioides in South-Central Chile. First, I carried out a literature review and ethnobotanical surveys to compile lists of the species of seaweeds used in Chile and in South-Central Chile. I recorded that just 3% of the species of seaweeds present in Continental Chile had traditional and/or contemporary use, and nine of them are currently used for production of polysaccharides. Then I used chemical analyses to test if species used for food and medicine have high nutritional values and antioxidant potential. The results showed high nutritional values and antioxidant content for the species studied, especially for the species Pyropia columbina, which presented high values of proteins, minerals and antioxidants. I also described the international and local context of intensification of seaweed extraction and the socioeconomic changes related to the polysaccharides market in South-Central Chile, I found changes in harvester demography, incorporation of new technologies, and increasing intensity and frequency of harvest. Then, I used manipulative harvest experiments and chemical analyses to evaluate how environmental factors and harvest affect the antioxidant potential of Mazzaella laminarioides; and I found no significant effects of abiotic, biotic predictors, or harvesting, on antioxidant potential. I also recorded a tendency for a negative relationship between temperature and total phenolic compounds. Lastly, I used a manipulative experiment to test the effects of harvest strategies on population size and reproductive potential of a population of M. laminarioides from South-Central Chile. During one harvesting season, I monitored the effects of harvest treatment on variables related to population size and reproductive potential. By the end of the experiment, the treatment that showed a recovery for most of the variables studied, particularly for population size, was hand-pull once. However none of the treatments recovered for total number of reproductive fronds, which can have negative effects on the population at long term. The results of the study suggest that the most sustainable strategy would be pulling fronds by hand, rotating harvesting areas and waiting longer to revisit the same spot. This would provide more and bigger fronds, and reduce the negative impact of harvest on the population.
Contemporary Hawaiʻi Non-Timber Forest Plant Gathering Practices
(University of Hawaii at Manoa, 2019) Kamelamela, Katie; Kamelamela, Katie L.; Botany
Non-Timber Forest Products (NTFPs) play a critical role for communities in the United States and across the globe. NTFPs include a diversity of plants and plant parts - from fruit, flowers and leaves to bark, and other parts – as well as fungi. NTFPs provide materials for a multitude of uses, including food, medicine, housing, the arts, and ceremonies. In Hawai‘i, NTFPs were used extensively and continue to be important to subsistence practices and/or make major contributions to cash economies. The purpose of this research is to assess in Hawai‘i what contemporary forest plants are wild harvested, why, and by whom, as well as the social, ecological, and economic implications of wild plant harvest. Methods to identify key forest plant species and harvesters include interviews, the first analysis of the Department of Land and Natural Resources plant permit database, surveys of markets and cultural events, including an online structured survey of plant harvesters across the islands. Results illustrate the importance of connection to place and practice, that conservation methods can be utilized while harvesting, that introduced species can play key substitution roles in contemporary practices, and Hawaiians are key harvesters with many others who engage and contribute to Hawai‘i forests. The kuleana, enduring concern and blessing, of forest resiliency sits between harvesters and formal social structures of management. Native species are still being harvested for subsistence, educational and economic purposes. This NTFP research informs future policy decisions affecting the cross section of contemporary cultural, economic, and conservation values of Hawai‘i forests.
Seed Ecology In Montane Forests On O‘ahu: Implications For Conservation
(University of Hawaii at Manoa, 2019) Hruska, Amy Marie; Drake, Donald R.; Botany
Hawai‘i is renowned for its unique biota, and for the degree to which that biota is imperiled by extinction. Key threats to the native flora include alien herbivores, the loss of mutualists, and competition with alien species. Ecological restoration on the islands focuses on removing alien ungulates, reducing invasive alien plants, and increasing native diversity and recruitment. Oʻahu is the most populated island and has lost the highest proportion of forest cover compared to other main Hawaiian Islands. Forest communities are dominated by alien plants at lower elevations but retain increasing native diversity at higher elevations. All forest types have lost all native seed dispersers, which may significantly alter the recruitment of native species. Ongoing restoration efforts on Oʻahu, in combination with novel interactions between alien birds and both alien and native plants, provide a unique opportunity to investigate novel interactions and assess the effects of restoration efforts to reduce invasive alien plants and increase the recruitment of native plant species. I conducted three field studies on O‘ahu investigating various aspects of seed ecology. In Chapter 2, I used seed rain traps and vegetation surveys, in three mixed and one native forest community, to investigate the distribution, reproduction, and dispersal of native and alien species adapted for bird dispersal. At all sites, alien seeds were more abundant in the seed rain and more frequently dispersed than native species, even where alien species made up <5% of the vegetation cover. Abundant alien species both in the vegetation and seed rain are among the most invasive alien species in the world. In Chapter 3, I measured and compared the seed rain and vegetation of native and alien bird-adapted species and the wind-dispersed native tree Metrosideros polymorpha in a three-year-old clear-cut surrounded by relatively intact forest to understand whether clear-cutting an invasive tree, Psidium cattleyanum, facilitates native plant regeneration. Two invasive alien understory species, Clidemia hirta and Rubus rosifolius, were the most abundant species in the seed rain in both habitats and the most abundant vegetation in the clear-cut. Seeds of the dominant native tree, Metrosideros polymorpha, were dispersed into the clear-cut, but few seedlings occurred, possibly owing to microsite limitation. In Chapter 4, I investigated the effect of canopy cover on the germination and seedling survival of four common native plant species—Alyxia stellata, Coprosma foliosa, Dianella sandwicensis, and Leptecophylla tameiameiae—in a managed mesic forest. Germination of A. stellata and C. foliosa was positively correlated with canopy cover. Germination of D. sandwicensis, and L. tameiameiae was independent of canopy cover. Invasive alien plants are regenerating more vigorously and more frequently dispersed than natives under current conditions. Two small-seeded alien species, C. hirta and R. rosifolius, are the most prolific invasive aliens in the seed rain and disperse into most forest microsites. Native recruitment is limited in all forest types and native species may benefit from human-mediated dispersal. Seed sowing in appropriate microsites is a potential method for increasing recruitment of common species.

Browse

Recent Submissions