scholarly journals Tests of Hexazinone and Tebuthiuron for Control of Exotic Plants in Kauai, Hawaii

Forests ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 576
Author(s):  
Wang ◽  
Awaya ◽  
Zhu ◽  
Motooka ◽  
Nelson ◽  
...  

Non-native plant species have become serious pests in Hawaii’s delicate island ecosystems. It is necessary to control invasive plants. The herbicides hexazinone and tebuthiuron were evaluated for defoliation efficacy to control several major invasive plants and for non-target effects on native plants at Site I in a rainforest at 1200 m elevation and Site II in a mesic area at 640 m elevation on the island of Kauai, Hawaii. The invasive weed species in the sites included daisy fleabane (Erigeron karvinskianus DC.), faya tree (Myrica faya Ait.), strawberry guava (Psidium cattleyanum Sabine), banana passion fruit (Passiflora mollissima Bailey), vaseygrass (Paspalum urvillei Steud.), and highbush blackberry (Rubus argutus Link. 1822). Native plants included ohia lehua (Metrosideros polymorpha Gaudich.), naupaka (Scaevola cerasifolia Labill.), pilo (Hedyotis mannii), hona (Urera glabra (Hook. & Arn.)), aalii (Dodonaea viscosa Jacq.), and amau (Sadleria sp.). The results showed that broadcast applications of hexazinone granules and tebuthiuron pellets were effective on some of those invasive species. Herbicidal tolerance varied among the native species. For example, D. viscosa showed high tolerance to hexazinone. S. cerasifolia was susceptible to hexazinone, but not to tebuthiuron. The inconsistent defoliation of Sadleria sp. occurred among different applications rates of the two herbicides. M. polymorpha, particularly when it was small, could tolerate hexazinone and tebuthiuron. U. glabra was severely injured by the two herbicides. H. mannii was moderately tolerant to hexazinone, but fairly sensitive to tebuthiuron. The invasive loblolly pine (Pinus taeda L.) was highly tolerant to hexazinone, but was very sensitive to tebuthiuron. M. faya was very sensitive to hexazinone, but very tolerant to tebuthiuron. P. cattleyanum was sensitive to both herbicides. Six and nine months after hexazinone and tebuthiuron treatment, respectively, native plants were transplanted into the Sites to observe injury from residual herbicides. Approximately less than 10% mortality was observed for the out-planted native species three months after planting (MAP), indicating that the native species showed less injury in the early period of transplant. The mortality of the three endangered species Kauai hau kuahiwi (Hibiscadelphis distans), Kauai delissea (Delissea rhytidosperma H.Mann) and kawawaenohu (Alsinidendron lynchnoides), however, increased as the MAP increased. Overall, broadcast treatments of hexazinone and tebuthiuron at rates higher than 1 kg active ingredient per hectare would be problematic. The dissipation half-life values of hexazinone and tebuthiuron in the 1-15 cm layer of soils at the two sites were approximately 7 days and greater than 180 days, respectively.

2021 ◽  
Author(s):  
Liping Shan ◽  
Ayub M.O. Oduor ◽  
Wei Huang ◽  
Yanjie Liu

Invasive plant species often exhibit greater growth and lower anti-herbivory defense than native plant species. However, it remains unclear how nutrient enrichment of invaded habitats may interact with competition from resident native plants to affect growth and defense of invasive plants. In a greenhouse experiment, we grew five congeneric pairs of invasive and native plant species under two levels of nutrient availability (low vs. high) that were fully crossed with simulated herbivory (clipping vs. no-clipping) and competition (alone vs. competition). Invasive plants produced more gibberellic acid, and grew larger than native species. Nutrient enrichment caused a greater increase in total biomass of invasive plants than of native plants, especially in the absence of competition or without simulated herbivory treatment. Nutrient enrichment decreased leaf flavonoid contents of invasive plants under both simulated herbivory conditions, but increased flavonoid of native plants under simulated herbivory condition. Nutrient enrichment only decreased tannins production of invasive species under competition. For native species, it enhanced their tannins production under competition, but decreased the chemicals when growing alone. The results indicate that the higher biomass production and lower flavonoids production in response to nutrient addition may lead to competitive advantage of invasive species than native species.


Author(s):  
M. Celeste Díaz Vélez ◽  
Ana E. Ferreras ◽  
Valeria Paiaro

Abstract Animal dispersers are essential for many non-native plants since they facilitate seed movement and might promote seed germination and seedling establishment, thereby increasing their chances of invasion. This chapter reviews the published literature on seed dispersal of non-native plant species by native and/or non-native animals. The following questions are addressed: (i) Are interactions between non-native plants and their animal dispersers evenly studied worldwide? (ii) Which are the distinctive traits (i.e. geographical origin, life form, dispersal strategy and propagule traits) of non-native plants that are dispersed by animals? (iii) Which are the most studied groups of dispersers of non-native plants around the world? (iv) Does the literature provide evidence for the Invasional Meltdown Hypothesis (non-native plant-non-native disperser facilitation)? (v) What is the role of animal dispersers at different stages of the non-native plant regeneration process? Our dataset of 204 articles indicates that geographical distribution of the studies was highly heterogeneous among continents, with the highest number coming from North America and the lowest from Asia and Central America. Most of the non-native plants involved in dispersal studies were woody species from Asia with fleshy fruits dispersed by endozoochory. More than the half of the animal dispersal agents noted were birds, followed by mammals, ants and reptiles. The dominance of bird-dispersal interactions over other animal groups was consistent across geographical regions. Although most of the studies involved only native dispersers, interactions among non-native species were detected, providing support for the existence of invasional meltdown processes. Of the total number of reviewed articles reporting seed removal, 74% evaluated seed dispersal, but only a few studies included seed germination (35.3%), seedling establishment (5.4%) or seed predation (23.5%). Finally, we discuss some research biases and directions for future studies in the area.


2006 ◽  
Vol 28 (1) ◽  
pp. 27 ◽  
Author(s):  
A. C. Grice

Most parts of the Australian rangelands are at risk of invasion by one or more species of non-native plants. The severity of current problems varies greatly across the rangelands with more non-native plant species in more intensively settled regions, in climatic zones that have higher and more reliable rainfall, and in wetter and more fertile parts of rangeland landscapes. Although there is quantitative evidence of impacts on either particular taxonomic groups or specific ecological processes in Australian rangelands, a comprehensive picture of responses of rangeland ecosystems to plant invasions is not available. Research has been focused on invasive species that are perceived to have important effects. This is likely to down play the significance of species that have visually less dramatic influences and ignore the possibility that some species could invade and yet have negligible consequences. It is conceivable that most of the overall impact will come from a relatively small proportion of invasive species. Impacts have most commonly been assessed in terms of plant species richness or the abundance of certain groups of vertebrates to the almost complete exclusion of other faunal groups. All scientific studies of the impacts of invasive species in Australian rangelands have focused on the effects of individual invasive species although in many situations native communities are under threat from a complex of interacting weed species. Invasion by non-native species is generally associated with declines in native plant species richness, but faunal responses are more complex and individual invasions may be associated with increase, decrease and no-change scenarios for different faunal groups. Some invasive species may remain minor components of the vegetation that they invade while others completely dominate one stratum or the vegetation overall.


2012 ◽  
Vol 30 (1) ◽  
pp. 51 ◽  
Author(s):  
Senilolia H. Tuiwawa ◽  
Gunnar Keppel

Mahogany (Swietenia macrophylla King) plantations cover a considerable area on the south-eastern parts of Viti Levu, Fiji. The understorey of these plantations often comprise a diverse, but undocumented, assemblage of native plant species. This study investigates the diversity, composition and regeneration potential of native plant species in the Wainiveiota mahogany plantation 40?50 years after establishment. Ten 10 m x 10 m plots were alternately placed at 10 m intervals perpendicular to a 200 m line transect. A total of 491 individual plants with dbh ≥ 1 cm, comprising 69 species, 51 genera and 34 families, were sampled. In addition to the exotic mahogany, there were 68 native (39 endemic, 24 indigenous and 5 identified to genus only) species recorded. Girronniera celtidifolia Gaud., Dillenia biflora (A.Gray) Martelli ex Dur. & Jacks and Barringtonia edulis Seem. had the highest recruitment and Endospermum macrophyllum (Muell.Arg.) Pax & Hoffm. was the dominant native species. Syzygium Gaertn. (Myrtaceae) was the most diverse genus and Myrtaceae the most diverse family. With 98% of the sapling recruitment consisting of native species, there is potential for re-establishment of a lowland rainforest dominated by native species over time.


Author(s):  
Susan Kalisz ◽  
Stephanie N. Kivlin ◽  
Lalasia Bialic-Murphy

Abstract Invasive species utilize a wide array of trait strategies to establish in novel ecosystems. Among these traits is the capacity to produce allelopathic compounds that can directly inhibit neighboring native plants or indirectly suppress native plants via disruption of beneficial belowground microbial mutualisms, or altered soil resources. Despite the well-known prevalence of allelopathy among plant taxa, the pervasiveness of allelopathy among invasive plants is unknown. Here we demonstrate that the majority of the 524 invasive plant species in our database produce allelochemicals with the potential to negatively affect native plant performance. Moreover, allelopathy is widespread across the plant phylogeny, suggesting that allelopathy could have a large impact on native species across the globe. Allelopathic impacts of invasive species are often thought to be present in only a few plant clades (e.g., Brassicaceae). Yet our analysis shows that allelopathy is present in 72% of the 113 plant families surveyed, suggesting that this ubiquitous mechanism of invasion deserves more attention as invasion rates increase across the globe.


2004 ◽  
Vol 52 (2) ◽  
pp. 141 ◽  
Author(s):  
V. P. Thomson ◽  
M. R. Leishman

Australian soils are naturally low in nutrient concentrations, particularly nitrogen (N) and phosphorus (P). Native plants are well adapted to low-nutrient soils, and can be adversely affected when exposed to higher concentrations of nutrients. The Hawkesbury Sandstone soils in northern Sydney are naturally low in nutrients, but often receive additional nutrient input from urban stormwater run-off. Increases in soil nutrients in urban bushland are associated with the presence of exotic species, and the decline in the diversity of native species. This study tested the hypothesis that high concentrations of nutrients, in particular P, in the disturbed soils of urban bushland, reduce survival of native plants. We examined the survival of native species under five different nutrient concentrations that are typical of nutrient-enriched urban bushland soil, in two glasshouse experiments. The experiments examined both survival of seedlings and survival of 6-month-old plants. We used native species that are adapted to both nutrient-poor and nutrient-rich soils. In general, the survival of native plants decreased with increasing nutrient concentrations. At soil total-P concentrations >200 mg kg–1, most plants died. Seedlings were more sensitive to added nutrients than the 6-month-old plants. Species that were from higher-nutrient soil had consistently higher survival than species from low-nutrient soils, under the nutrient addition treatments. These results suggest that at high soil nutrient concentrations typical of stormwater-affected urban bushland, native plant species of low-nutrient soils will be unable to survive. If ecological restoration works are to be done in such areas, replanting with more mature plants from naturally high-nutrient habitats is likely to be the most successful. However, restoration of these areas may have limited success and they are likely to remain dominated by exotic plant species.


Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 241
Author(s):  
Edith Cruzado-Tafur ◽  
Katarzyna Bierla ◽  
Lisard Torró ◽  
Joanna Szpunar

The capability of native plant species grown in polluted post-mining soils to accumulate metals was evaluated in view of their possible suitability for phytoremediation. The study areas included two environmental liabilities in the Cajamarca region in the Peruvian Andes. The content of As, Ag, Cd, Cu, Pb, and Zn was determined in individual plant organs and correlated with soil characteristics. The degree of the pollution depended on the metal with results ranging from uncontaminated (Cd) to moderately (Zn), strongly (As, Cu), and extremely contaminated (Pb, Ag) soils. The metals were mainly present in the fractions with limited metal mobility. The bioaccumulation of the metals in plants as well the translocation into overground organs was determined. Out of the 21 plants evaluated, Pernettya prostrata and Gaultheria glomerate were suitable for Zn, and Gaultheria glomerata and Festuca sp. for Cd, phytostabilization. The native species applicable for Cd phytoremediation were Ageratina glechonophylla, Bejaria sp., whereas Pernettya prostrata Achyrocline alata,Ageratina fastigiate, Baccharis alnifolia, Calceolaria tetragona, Arenaria digyna, Hypericum laricifolium, Brachyotum radula, and Nicotiana thyrsiflora were suitable for both Cd and Zn. None of the studied plants appeared to be suitable for phytoremediation of Pb, Cu, As and Ag.


2019 ◽  
Vol 25 ◽  
Author(s):  
Gordon Frankie ◽  
Ingrid Feng ◽  
Robbin Thorp ◽  
Jaime Pawelek ◽  
Marissa Helene Chase ◽  
...  

Bees visit native and non-native plant species for pollen and nectar resources in urban, agricultural, and wildland environments. Results of an extensive survey of bee-flower collection records from 10 California cities from 2005-2011 were used to examine host-plant records of native and non-native ornamental plants to diverse native and non-native bee species; five cities were from northern California and five were from southern California. A total of 7,659 bees and their floral host plants were examined. Of these, 179 were Apis mellifera and 7,390 were non-Apis. Only four other non-native species (all in Megachilidae) were recorded in the survey, and together they accounted for 402 individuals. These bees have been databased in preparation for deposition in the University of California-Berkeley Essig Museum of Entomology. We identified 229 bee species and 42 genera visiting native and non-native plant types in urban areas. Of the 229 species, 71 bee species were collected from only native plants; 52 were collected from only non-native host plants; and 106 were collected from both types of plants. Native bee species were common on native plants and non-native plants, but there were substantially more non-native bee species visiting non-native plants compared to native plants. Flowering periods in months were similar for both types of plants, but non-natives tended to flower later in the year. We propose that using native and non-native plants improves habitat gardening by increasing opportunities for attracting a richer diversity of bee species and for longer periods. Knowing basic bee-flower relationships in an area is key to planning a bee habitat garden with a variety of plant types, regardless of their geographic origin. 


Author(s):  
Fernanda Ribeiro da Silva ◽  
Marco Aurélio Pizo

Abstract Restoration aims to rebuild not only species but also the tangled interactions between species that ensure communities perpetuate by themselves. In tropical forests, restoration of seed dispersal interactions is essential because most plant species depend on animals to spread their seeds. A big challenge in restoring such forests is dealing with invasion by non-native species. Non-native plant species may outcompete and eliminate native species from the community, potentially disrupting or arresting the restoration process. Once established, invasive non-native plants are usually incorporated into the local seed dispersal network, potentially causing loss of biodiversity by competition with native species. This chapter reports on a case study of a 25-year old restored forest invaded by several bird-dispersed plant species. We assessed network metrics at the species level to specifically evaluate the role performed by invasive non-native species in the structure of the bird - seed dispersal network. The removal of invasive non-native plants and the re-establishment of native plant communities should be considered for the restoration of habitats invaded by non-native plants. For this reason, we discuss the impacts of removing such non-native plants and explore the consequences for the structure of the overall network. Because restoration areas are open systems, even after the removal of invasive non-native plant species they can return via seed dispersal. So, both the control and management of invasive non-native species would be more effective if planned with a landscape perspective. We also point out relevant management aspects to avoid the negative influence of invasive non-native plants on the seed dispersal interactions occurring between native plant and bird species in restored tropical forests.


Author(s):  
M. Celeste Díaz Vélez ◽  
◽  
Ana E. Ferreras ◽  
Valeria Paiaro ◽  
◽  
...  

Animal dispersers are essential for many non-native plants since they facilitate seed movement and might promote seed germination and seedling establishment, thereby increasing their chances of invasion. This chapter reviews the published literature on seed dispersal of non-native plant species by native and/or non-native animals. The following questions are addressed: (i) Are interactions between non-native plants and their animal dispersers evenly studied worldwide? (ii) Which are the distinctive traits (i.e. geographical origin, life form, dispersal strategy and propagule traits) of non-native plants that are dispersed by animals? (iii) Which are the most studied groups of dispersers of non-native plants around the world? (iv) Does the literature provide evidence for the Invasional Meltdown Hypothesis (non-native plant-non-native disperser facilitation)? (v) What is the role of animal dispersers at different stages of the non-native plant regeneration process? Our dataset of 204 articles indicates that geographical distribution of the studies was highly heterogeneous among continents, with the highest number coming from North America and the lowest from Asia and Central America. Most of the non-native plants involved in dispersal studies were woody species from Asia with fleshy fruits dispersed by endozoochory. More than the half of the animal dispersal agents noted were birds, followed by mammals, ants and reptiles. The dominance of bird-dispersal interactions over other animal groups was consistent across geographical regions. Although most of the studies involved only native dispersers, interactions among non-native species were detected, providing support for the existence of invasional meltdown processes. Of the total number of reviewed articles reporting seed removal, 74% evaluated seed dispersal, but only a few studies included seed germination (35.3%), seedling establishment (5.4%) or seed predation (23.5%). Finally, we discuss some research biases and directions for future studies in the area.


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