Native Plant Research Articles

The Potential of Biocrust-Forming Cyanobacteria to Enhance Seedling Growth of Native Semi-arid Plants Through Seed Biopriming

AbstractIn drylands, extreme environmental conditions pose a challenge for restoration, especially on a large scale. Direct seeding is the most cost-effective approach to restore large areas, but it requires improvements to enhance seedling survival and establishment. For this purpose, biopriming seeds with cyanobacteria is promising due to their plant growth-promoting properties. We evaluated the effect of seed biopriming with native biocrust-forming cyanobacteria on seed germination and radicle length of four native plant species, two perennials (Macrochloa tenacissima and Thymus hyemalis) and two annuals (Plantago ovata and Stipa capensis), chosen for their ubiquity in Mediterranean drylands. Treatments included seed biopriming with cyanobacteria inoculants (biomass + exudate), seed priming only with the cyanobacterial exudate, and controls (BG11 culture medium and distilled water). Biopriming effect was assessed individually for four native biocrust-forming cyanobacteria species: Nostoc commune, Tolypothrix distorta, Trichocoleus desertorum, and Leptolyngbya frigida. Seed biopriming showed no effect on germination with similar rates among treatments (on average, 45 ± 12.6% for M. tenacissima, 38.8 ± 12.4% for T. hyemalis, 91.7 ± 9.8% for P. ovata and 77.6 ± 10.8% for S. capensis). However, biopriming significantly affected radicle length of annual plants. Radicles were significantly increased in P. ovata when treated with cyanobacterial exudates (15–30% increase over control), and in S. capensis when treated with cyanobacterial biomass + exudate (26–42% increase over control). These results indicate that the effect of seed biopriming is species specific, but selecting the appropriate plant species and biopriming treatment can enhance plant survival and establishment in drylands, making restoration efforts more successful.

Revealing How Human Activity and Native Plants Outshine Climate in Shaping New Invasive Alien Plant Elevational Patterns in Nature Reserves

ABSTRACTAimWe aim to investigate whether invasive alien plants introduced at different times exhibit variations in elevational distribution patterns and to explore the correlations of these patterns with climate, native plants and human activity.LocationGuangxi, China.MethodsWe recorded plant richness and cover across elevational gradients at 25–34 sites within each reserve, utilising 84–134 roadside plots per site. Using generalised linear mixed model (GLMM), we assessed the impacts of climate, native plants and human activity on the distributions of all, old and new invasive alien plants across the region and within the nature reserves.ResultsAt regional scales, the cover of all, new and old invasive alien plants decreased with increasing elevation, while only the richness of old invasive alien plants exhibited a similar pattern. Contrasting patterns were observed in Dayao Mountain, where the cover of old invasive alien plants decreased while the cover of new invasive alien plants increased. The richness patterns of all and new invasive alien plants were opposite between Dayao Mountain and Yachang Orchid. Moreover, native plant richness was negatively correlated with the richness of invasive alien plants, while interference intensity positively affected new invasive alien plants at both regional and reserve scales. At the regional scale, native plant richness accounted for 78.27%, 91.94% and 60.9% of all, old and new invasive alien plants respectively. Interference intensity accounted for 33.85% of the variation in new invasive alien plants. Annual mean temperature positively influenced the cover of all and old invasive alien plants at both regional and reserve scales, explaining 36.91% and 74.28% of their regional variation. Additionally, interference intensity and distance to human settlements positively impacted the cover of new invasive alien plants, contributing to 50.95% and 31.92% of their variation at regional scales.Main ConclusionThe distinct distribution patterns of old and new invasive alien plants highlight the significance of residence time in understanding their dynamics. Climate factors constrain the cover distribution of all and old invasive alien plants, whereas interference intensity and distance to settlements determine the distribution of new invasive alien plants. Notably, native plants play a vital role in preventing the establishment and spread of invasive alien plants within nature reserves, and their effectiveness increases with longer residence times. Our findings highlight the critical importance of minimising human interference and conserving native species for the effective management of invasive alien plants in nature reserves.

Melissopalynological study of Melipona (Eomelipona) torrida Friese, 1916: a native stingless bee from southern Brazil

Few data are on bee–plant interactions for the Melipona torrida bee in southern Brazil. This is a native bee vulnerable to extinction that pollinates native plants and produces honey that is especially appreciated by local populations. Aiming to evaluate the floral sources visited by Melipona torrida bee in southern Brazil a palynology investigation on honeys of this bee were carried out. Honeys were extracted each month from March 2020 to November 2021 of hives from two locations of Rio Grande do Sul (Cachoeirinha and Canoas). The 34 samples were analysed with a light microscope. In the honey samples of the Melipona torrida bee were identified 39 pollen types, principally tree plants. Melipona torrida bee visited frequently the plants of Myrcia type, Eucalyptus sp., Schinus terebenthifolia, Mimosa bimucronata, Parapiptadenia rigida, Morus nigra and Solanum sisymbrifolium. The pollen diagram show differences in pollen percentages throughout the year and CONISS grouped the samples in five groups (MT-1–MT-5). Richness of pollen types of samples was low in the months of winter and March and high in the honeys of months of Spring and Summer. The honeys were monofloral and heterofloral, and native plants were more visited than exotic species. The 33 pollen types from honey of Melipona torrida bee from southern Brazil can help in the knowledge of the bee–plant interaction of this native bee and propose appropriate plant management around the hives.

Non-Native Plants Provide Nectar and Host Plant Resources to Native Butterflies

Urban restoration projects often aim to completely remove non-native plant species from the restored landscape and replace them with native plant species. However, this is unrealistic as early successional plants in urban settings comprise predominantly of non-native plant species. In this study, we investigate whether native butterfly species showed a preference on using native versus non-native plant species in their nectar sourcing and caterpillar host plant choice in two urban gardens at Monash University Malaysia. Native butterflies significantly preferred non-native plant species as nectar food plants, suggesting butterflies are generalists in nectar sourcing. Native butterflies showed no preference towards non-native plants as caterpillar host plants. However, six native butterfly species in our study (Zizula hylax, Hypolycaena erylus, Chliaria othona, Junonia orithya, Yppthima spp., and Eurema hecabe) can use non-native plants as their caterpillar host plants. This demonstrates the usefulness of these non-native plant species in an urban garden in maintaining native butterfly biodiversity. This study indicates a paradigm shift is required among urban ecologists to recognize that not all non-native plants have negative impacts on biodiversity. For more effective urban restoration planning and management, further research emphasising how native insects use non-native plant species is required to maximise biodiversity and ecosystem services restoration.

GPS telemetry facilitates the identification of forage plant species for endangered Carnaby’s cockatoos (Zanda latirostris) at inland breeding sites and post-breeding dispersal locations in Western Australia

Carnaby’s cockatoos (Zanda latirostris) are an endangered species that has experienced major loss of habitat over the past century. Proponents seeking land clearing approval that may impact Carnaby’s cockatoos need to provide detailed habitat assessment. However, the current forage species list is outdated and generally restricted to the Swan Coastal Plain rather than the Carnaby’s full distribution range. This study provides an updated forage list, including the Swan Coastal Plain and much of the Carnaby’s breeding and non-breeding areas outside this region. Carnaby’s cockatoos were captured and satellite tagged, at five breeding sites in the wheatbelt and Great Southern areas in Western Australia (between 2017 and 2022). Spatial data collected from the tags facilitated the identification of forage plants used by Carnaby’s cockatoos. A total of 44 ‘new’ native plant species were identified as Carnaby’s cockatoo forage species, including five genera that have not previously been recorded. The updated forage list will inform proponents and regulators on the potential use of habitat patches by Carnaby’s cockatoos, aiding the referral process and enabling the protection and conservation of important and diminishing habitat resources.

Estimation of genetic polymorphism in quince (Cydonia oblonga Mill.) genotypes using morphological traits and molecular (DNA barcoding) characterizations.

Quince (Cydonia oblonga) is a medicinal plant and a member of family Rosaceae. It is native plant of Asia Minor and Europe. It is used in production of jam and jellies and also as a remedy of several ailments. The present study was conducted to evaluate the genetic polymorphism based on morphological and molecular traits. Different varieties of Quince were collected from different ecological zones of Khyber Pakhtunkhwa Pakistan and a total of 26 different morphological traits were recorded among studied genotypes. Based on qualitative morphological trait study, the variety collected from Tindodag was unique one with highest fruit weight (328.82 g). The lowest fruit weight (68.38 g) was recorded for Talash genotype. The Charbagh and Tindodag genotypes showed highest seed length (10.6 mm) while genotypes of Chitral was recorded as lowest (8.4 mm). Statistically, significant level of variation was noted with coefficient of variance ranged from 2.23% to 30.38%. Based on correlation analysis, fruit length had strongly correlation with fruit weight (r = 0.89**), Average Fruit width was found significant with fruit weight (r = 0.90**). Similarly, the Core Width was found strongly significant with Core Length (r = 0.95**). ANOVA analysis indicated 10 quantitative characters to be highly significant, 2 significant and 1 insignificant. Principal component analysis was also computed for the 13 quantitative traits with Eigen value of 0.48 and a total variance of 97.78%. The first principal component shows total variation of 52.52%. In PC2 the total variation was 80.15%, PC3 94.06% while in PC4 it was 97.78%. The NCBI BLAST results shows that all the genotypes have similar origin except Tindodag genotype, which shows differences in its origin. Accession number for all other genotypes is MN216014.1, while accession number of Tindodag genotype is KF861967.1. Based on this study, it can be concluded that Tindodag genotype is unique out of the studied localities. NCBI BLAST have provided further support for the drawn conclusion.

Invasive plants grow taller under experimental warming, but mediated effects of biotic interactions are species‐specific

Understanding the responses of non‐native plants to climate change while accounting for biotic interactions is key to predicting and mitigating future invasion risks. Non‐native invasive plants may benefit from or decline in the face of climate change, relative to native competitors. Non‐native plants might also suffer less than native plants from natural enemies such as herbivores, which could give non‐natives a competitive advantage. However, we lack an understanding of how non‐native plants will compete with native plants in a warming climate, while accounting for the effects of herbivore pressure. To test the potential interactions between warming, herbivore pressure and competition, we set up a common‐garden experiment in Trondheim, Norway, using five non‐native plants growing either alone or in competition with a native plant community. These plants were subjected to herbivore exclusion and artificial warming treatments, using open‐top chambers. We found that under warming, three non‐native species had greater biomass and all five species were taller than when grown without warming. Competition with native species reduced the biomass of three non‐native species and herbivore exclusion resulted in taller plants for three non‐native species. Native community biomass was not affected by either warming or herbivore exclusion. Furthermore, the native community was not affected by competition with any non‐native plant except Centaurea montana, which resulted in lower native community biomass, suggesting that C. montana is likely to be the most detrimental of these non‐native species to native communities. Competition with natives reduced the positive effects of warming on biomass for only one species, Alchemilla mollis. Our study strongly suggests that a warming climate may benefit invasive plants more than native plants, but for some species these effects will be mediated by biotic interactions in idiosyncratic ways, depending on the identity of both native and non‐native species. This will present a challenge to predicting plant invasion success under climate change while accounting for biotic interactions.

Intraspecific diversity mitigates the negative soil-legacy impacts of an invasive plant.

Elton's biotic resistance hypothesis predicts that biodiversity can resist the establishment of invasive plants. However, whether and how within-species diversity mediates the impacts of successfully established invaders is poorly understood, particularly in the face of climate change. We used an experimental system to test the effect of intraspecific diversity of a native foundation species, Scirpus mariqueter, on the soil-legacy impacts of a global plant invader, Spartina alterniflora, under well-watered and drought conditions. We found that more diverse populations of the native plant buffered against the negative soil-legacy impacts of the invader on the native plant. This intraspecific diversity effect was due to a complementarity effect triggered by invader-shaped soil biota, and emerged in both well-watered and drought conditions. Compared with the previous finding that intraspecific diversity of the native plant can reduce the performance of the invader through soil biotic feedbacks, this study provides further evidence that it helps to mitigate the negative soil-derived impacts of the invader. These findings together emphasize the need for management measures that promote and restore native intraspecific diversity in a changing world.

Understanding the Influence of Secondary Metabolites in Plant Invasion Strategies: A Comprehensive Review

The invasion of non-native plant species presents a significant ecological challenge worldwide, impacting native ecosystems and biodiversity. These invasive plant species significantly affect the native ecosystem. The threat of invasive plant species having harmful effects on the natural ecosystem is a serious concern. Invasive plant species produce secondary metabolites, which not only help in growth and development but are also essential for the spread of these plant species. This review highlights the important functions of secondary metabolites in plant invasion, particularly their effect on allelopathy, defense system, interaction with micro soil biota, and competitive advantages. Secondary metabolites produced by invasive plant species play an important role by affecting allelopathic interactions and herbivory. They sometimes change the soil chemistry to make a viable condition for their proliferation. The secondary metabolites of invasive plant species inhibit the growth of native plant species by changing the resources available to them. Therefore, it is necessary to understand this complicated interaction between secondary metabolites and plant invasion. This review mainly summarizes all the known secondary metabolites of non-native plant species, emphasizing their significance for integrated weed management and research.

Overview of plant species translocations in Luxembourg

In Luxembourg, 34 % of native plants and archaeophytes are considered threatened or regionally extinct. Species translocations have been implemented in Luxembourg for more than 25 years as a conservation strategy to counteract biodiversity loss. In this overview, we have compiled data on conservation actions implemented between 1997 and 2023. The information collected includes the translocation locations, the plant taxa targeted, the methods used, and the monitoring conducted. For a subset of translocations, we have also included data on the survival of planted juveniles. Examples of translocations from various habitat types were also presented to illustrate different approaches. We found that 585 translocations involving 99 taxa from 26 families were initiated by four main institutions in Luxembourg. The conservation actions mainly targeted Endangered and Critically Endangered, but also Least Concern species. Translocations mainly took place in open land habitats, particularly in grasslands and arable land, with a higher density in the southwestern part of the country. 39 % of the translocations took place in national nature reserves whereas 21 % were in areas without any legal protection status. Planting young plants was the preferred method rather than sowing seeds. In 89 % of the translocations, monitoring was conducted by recording survival of the plants, while natural recruitment of new individuals was rarely recorded. 68 % of the translocations were judged successful by the practitioners, mostly based on transplant survival. Detailed data for the subset of 31 grassland species showed that the survival rate of about half of the species considered successful varied between 25 and 71 %. Translocations are essential for the long-term conservation of plant species, but protection and adaptive management of translocation sites are also essential. Translocations conform to national and European priorities for increasing habitat restorations to counteract species decline. To improve conservation outcomes, actions such as translocations need to be consistently documented, monitoring standardized, and experience needs to be shared among stakeholders.

Printing with Natural Dye Extract from Japanese Knotweed Leaves

AbstractInvasive alien plants are detrimentally displacing native plant species and pose a challenge in terms of how their overgrowth can be utilized effectively. In our study, the leaves of one of the world’s worst invasive species, Japanese knotweed, were used to produce a green natural dye. This dye was screen-printed onto various substrates, including cotton and polyester fabrics, commercial cellulose papers, and innovative papers made from the stems of Japanese knotweed. The printed substrates were evaluated using color measurements and fastness properties. The aim of the study was also to investigate the influence of additives in the printing inks, such as sodium carbonate, citric acid, copper and aluminum sulfates, on the color and fastness properties of the prints. The colors of the prints obtained varied, ranging from primarily yellowish-green to brownish-yellow with the addition of citric acid, orange-brown with sodium carbonate, orange-yellow with aluminum sulfate, and brown with copper sulfate. The prints had excellent fastness to dry rubbing and moderate fastness to light. The prints of lower and medium dye concentrations on fabrics had very good fastness to wet rubbing and wet ironing, and on cotton even good fastness to washing. The additives in the printing inks, such as sodium carbonate and metal sulfates, reduced the abrasion resistance of the prints on paper and the wet fastness of the prints on fabrics, but only the metal sulfates had a positive effect on the light fastness of the prints.

A Fully Validated LC-MS Quantitation Method for Psychoactive Compounds Found in Native South American Plant Species

Psychoactive drugs are compounds that alter the function of the central nervous system, resulting in changes in perception, mood, cognition, and behavior. A subclass of psychoactive drugs, psychedelics, are hallucinogenic drugs that can trigger psychedelic experiences and possible changes in mental perception. The potential use of psychedelics as a therapeutic has led to an increase in clinical research focusing on the treatment of mental disorders including anxiety and depression. There are numerous species belonging to Psychotria and Banisteriopsis which have been reported to contain psychedelic and psychoactive compounds; however, there is a lack of validated analytical methods for raw plant material, which is crucial if these plants are to be commercially cultivated for medicines. This study provides a fully validated method using ultra-high performance liquid chromatography (UHPLC) coupled to mass spectrometry (MS) for the following six compounds: tryptamine, N,N-dimethyltryptamine (DMT), 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT), tetrahydroharmine (THH), harmaline, and harmine. The validated method was used to determine the psychoactive concentrations in Psychotria viridis, Psychotria carthagenensis, Banisteriopsis caapi, and Alicia anisopetala. Validation parameters were established; linearity (R2 = 0.988–0.999), limit of detection (LOD) (0.06–0.11 ng/mL), limit of quantitation (LOQ) (0.18–0.34 ng/mL), accuracy, precision, extraction efficiency (>98%), recovery (74.1–111.6%), and matrix effect (70.6–109%) were all evaluated. All six compounds eluted within nine minutes, with a total analysis time of 20 min including column equilibration. This method establishes a high-throughput method for the robust analysis of psychedelics which may see future use in agricultural research and industry.

A Study on Antioxidant and Gastro-protective Effects of Trachyspermum ammi Linn Extract Using Different In-vitro Techniques

The use of a plant's seeds, berries, roots, leaves, bark, or flowers for therapeutic purposes is known as herbal medicine, often called botanical medicine or phytomedicine. There is a long history of using herbs outside of traditional treatment. The use of herbal medicine in treating and preventing disease is becoming more widespread due to advancements in clinical research, analysis, and quality control. There is a long history of using native plants in traditional medicine. Plants serve as the primary source of resources for the conventional medical procedures practiced in rural and tribal regions in India and other countries. Ajowan, or Trachyspermum ammi, is a widely used name. One of the traditional possible herbs used as a spice in daily life is ajwain, or Trachyspermum ammi L., a member of the Apiaceae family. Fruits, vegetables, herbs, and spices all contain phenolic compounds, which have potent anti-inflammatory, antigenotoxic, antioxidant, and anticancer properties. A Soxhlet extractor was utilized to extract the methanol from the dried seeds of Trachyspermum ammi. The Fenton reaction was used to measure the seed's total phenolic content, and it showed good antioxidant activity at various dosage concentrations. With ascorbic acid serving as the standard reducing agent, the antioxidant activity of the seed extract was evaluated. The UV-visible spectrophotometer was used to obtain the current results. A notable concentration-dependent free radical scavenging and reduction power was demonstrated in this plant extract, Trachyspermum ammi. Using SGOT and SGPT enzymes, we also determined that the gastroprotective action of T. ammi extract was significantly higher than that of the standard medication Liv52 and control liver enzymes. The liver histology slide treated with T. ammi extract shows a typical liver lobule. The hepatocytes are polyhedral, have eosinophilic cytoplasm, and typically have a central nucleus. Endothelially lined sinusoids are located between the hepatocyte cords and exhibit normal liver histology compared to control and Liv52-treated groups. Significantly less intestinal histology was observed as compared to untreated control. The current study concludes that Trachyspermum ammi extract may have a natural antioxidant and gastroprotective activity. Trachyspermum ammi is a great way to add gastroprotective and antioxidant phenolic components to your diet.

Non-native plants invasions public parks, friends or foe?

AbstractNon-native plants (NNPs) are known as alien species, which are brought outside of their natural habitats due to human activity and have an impact on the biodiversity of native plants (NPs). Because parks serve as havens for NNPs, they may pose a threat to them. The present study documented the NNPs conserved in the parks distributed in Cairo and the new settlements surrounding it. Thirty field visits were conducted from spring 2022 to Spring 2023 in 19 parks distributed in the study area. In each park NNPs were recorded. Native range, natural habitats and national geographical distribution, ethnobotanical uses, threats, and human risks were determined for NNPs. The results indicated that 37 wild NNPs belonged to 18 families were recorded in the surveyed gardens. Six species belonged to Tropical America, and other six species belonged to Mediterranean region. All recorded species were distributed in the Nile region. Thirty-six species used as medicinal plants and 31 species for human food. All recorded NNPs were exposed to one or several types of threats in their natural habitats, while 10 species were found to have a toxic effect on humans. Our results showed that the Egyptian botanic and public gardens could play an important role in the future as a source of NNPs that could be used for their contributions to ecosystem functioning and services. Also provides evidence for the essential role of public gardens in the Egyptian Nile Region for plant diversity conservation, as helps conserve wild species from other geographical regions.

Simulated herbicide drift alters native plant flowering phenology.

Data for herbicide effects on plant flowering are needed to determine potential impacts on plant reproduction. Thus, flowering phenology was determined for up to 12 weeks after herbicide treatment for native Willamette Valley plants growing in small plots on two Oregon State University experimental farms. Six perennial species were evaluated: Camassia leichtlinii (CALE), Elymus glaucus (ELGL), Eriophyllum lanatum (ERLA), Festuca idahoensis subsp. roemeri (FEID), Iris tenax (IRTE), and Prunella vulgaris var. lanceolata (PRVU). Effects of glyphosate and dicamba, alone and in combination, were determined using simulated drift rates of 0.1 or 0.2 x field application rates (FAR) of 1119 g ha-1 active ingredient (a.i.) (830 g ha-1 acid glyphosate) for glyphosate and 560 g ha-1 a.i. for dicamba. Flowering phenology was evaluated as stage of development on a scale from no buds (converted to 0), buds (1), pre-flowering (2), flowering (3), post-flowering (4), to mature seeds (5) before herbicide treatment and for 12 weeks after treatment. Flowering response to herbicides varied by species and farm; but, in general, dicamba and glyphosate resulted in earlier flowering stages (delayed or not full flowering) for the dicot ERLA, and to a lesser extent, PRVU; and glyphosate resulted in earlier flowering stages for the monocot IRTE. Based on these data, the concentration of herbicide affecting flowering stage was 0.1 x FAR. Once flowering stage was inhibited by dicamba and glyphosate, plants generally did not recover to full flowering. This study provided evidence that common herbicides can affect flowering phenology of native plants with implications for seed production.

Soil quality and vegetation identification in closed sand-gravel mining area in West Java, Indonesia

This paper examines the soil quality and vegetation identification in a closed sand gravel mining area in West Java, Indonesia. Revegetation of disturbed mining areas is crucial in restoring soil quality and environmental function. The native plants play a pivotal role in accelerating this process. The goal of this mixed-methods study in closed sand-gravel mining was to look at the nutrient profile, texture, and microbial count of the soil in two places in the foothills of a closed mine, as well as to find and name the plant species that naturally grow well and to find and name the plant species that naturally grow well when it rains. The observation showed that the soil near the spring was more fertile than the soil away from the spring, and the soil surrounding the spring supported a higher plant density. The study area supported the growth of 22 plants, including two trees, 13 shrubs, two sedges, four grasses, and one fern. Notably, two perennial trees–Mexican lilac and beech wood–were successfully grown during the initial greening program conducted three years ago. The bacterial and fungal counts for both soils were 109 colony-forming units (CFU) per g and 104 CFU/g, respectively. We found different morphology in the soil fungal colonies, while the bacteria colonies remained homogenous. The results underscore that the soil in the disturbed mine area still supported the native plant growth. These findings are crucial for the preservation of these native plants, making them crucial for the intensive revegetation of the mining area prior to the introduction of suitable perennial trees.

Changing Bird Migration Patterns Have Potential to Enhance Dispersal of Alien Plants From Urban Centres

ABSTRACTThere is increasing recognition that alien species may be ‘sleepers’, becoming invasive with favourable changes in conditions, yet these changes remain difficult to predict. As populations of frugivorous birds shift with urbanisation and climate change, they could provide dispersal services for introduced fruiting plants that have previously been considered benign. This is likely to be especially problematic at higher latitudes where bird migration phenologies are altering rapidly. However, any consequences for fruit dispersal have not yet been explored. Here, we use Helsinki, Finland, to investigate whether (i) streetscapes provide birds with a fruit resource that differs from urban forest fragments and (ii) the chances for dispersal of alien species (i.e., preferential consumption of native fruits). While there were both more fruits and birds in streetscapes (replicated across multiple years), fruits were not consumed preferentially according to origin. Additionally, seed analysis from faecal samples of blackbird Turdus merula L., a previously migratory but increasingly resident species, suggested that alien and native plants are equally likely to be dispersed. These results indicate that birds could be dispersing alien species more frequently than previously thought and highlight the complex effects of changing climates on potentially invasive species.

Climatic drought and trophic disruption in an endemic subalpine Hawaiian forest bird

Overexploitation, habitat conversion, and introduced species have caused unprecedented extinctions and heavily degraded native bird populations in island ecosystems. In the Hawaiian Islands, stemming these losses has proven difficult as the highly specialized avifauna are often impacted – among other things – by poorly understood trophic disruptions as well as persistent climatic shifts. Here we investigate these dynamics by examining the trophic positions of 7 different taxa of producers and consumers across the last century in the subalpine māmane (Sophora chrysophylla) forest ecosystem on the island of Hawaiʻi. From museum collections and contemporary sampling, we analyzed the stable nitrogen (δ15N) values of producers and consumers to identify trophic and source amino acids and derive trophic enrichment constants specific to this food web. This enables us to reconstruct the diet of the palila (Loxioides bailleui), a critically endangered finch whose population recently declined 90 %. Our results show that from 1890 to 2006, the palila trophic position declined from 2.6 to 2.2, with cascading implications for its diet. Bayesian mixing model reconstructions indicate that palila trophic position changes likely arose from a 76 % decline (69.3 % to 16.6 % of diet) in the consumption of native moth caterpillars, and a 172 % increase (30.7 % to 83.4 %) in native plants. From the available ecosystem variables, exploratory Bayesian multiple regressions selected surface temperature changes, and the interactions of surface temperatures with drought and caterpillar parasitism as the primary drivers of these trophic changes. Despite the predicted increases of warming and drought, management interventions may build resiliency in this unique island ecosystem.

Cytotoxic monoterpenoid indole alkaloids from Tabernaemontana bovina.

Chemical investigation of the native medicinal plant Tabernaemontana bovina led to the isolation of five previously unreported monoterpenoid indole alkaloids tabernovinaines A-E (1-5) together with twenty-seven known analogs (6-32), including a bisindole alkaloid 1 with the (E)-4-aminobut-3-en-2-one fragment, as well as a unique cage skeleton 2 containing 6/5/8/6/6 ring system. The chemical structures of these unreported compounds were elucidated using mass spectrometry, NMR spectroscopy, circular dichroism, density functional theory calculations, and derivatizations. The activity evaluation shows that the bisindole alkaloid 1 revealed a potential cytotoxic effect by inducing HepG2 cell apoptosis and damaging clonal sphere expansion.

Native Plant Materials Directory

Native Plant Materials Directory