scholarly journals Second Year Post-Wildfire Recovery Inhibits Dispersal of Allelopathic, Invasive Forb

Author(s):  
Benjamin Marcus Schlau

Abstract The increasing frequency of wildfires in Southern California’s Mediterranean-type habitats has been facilitating the displacement of native plants by invasive annuals. Black mustard ( Brassica nigra ) is an abundant, allelopathically harmful, invasive forb, which readily colonizes soil niches following most disturbances. Wildfires, however, are unlike other forms of disturbance because they can fundamental alter plant-soil interactions through both physical and chemical changes in the soil. Here, a comparative field study of burned and unburned sites suggests that the Woolsey Fire – the largest wildfire ever recorded in California’s Santa Monica Mountains – inhibited dispersal of B. nigra and changed how it interacts with other plant species in the second year of post-fire recovery. More surprisingly, native plants were more likely to replace B. nigra than non-native plants in burned sites. These results indicate the possibility of post-fire seeding with specific “fire follower” native plant species may allow native flora to occupy soil niche space until longer-lived, competitive native shrubs establish.

Insects ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 471
Author(s):  
Angelica M. Reddy ◽  
Paul D. Pratt ◽  
Brenda J. Grewell ◽  
Nathan E. Harms ◽  
Ximena Cibils-Stewart ◽  
...  

Exotic water primroses (Ludwigia spp.) are aggressive invaders in aquatic ecosystems worldwide. To date, management of exotic Ludwigia spp. has been limited to physical and chemical control methods. Biological control provides an alternative approach for the management of invasive Ludwigia spp. but little is known regarding the natural enemies of these exotic plants. Herein the biology and host range of Lysathia flavipes (Boheman), a herbivorous beetle associated with Ludwigia spp. in Argentina and Uruguay, was studied to determine its suitability as a biocontrol agent for multiple closely related target weeds in the USA. The beetle matures from egg to adult in 19.9 ± 1.4 days at 25 °C; females lived 86.3 ± 35.6 days and laid 1510.6 ± 543.4 eggs over their lifespans. No-choice development and oviposition tests were conducted using four Ludwigia species and seven native plant species. Lysathia flavipes showed little discrimination between plant species: larvae aggressively fed and completed development, and the resulting females (F1 generation) oviposited viable eggs on most plant species regardless of origin. These results indicate that L. flavipes is not sufficiently host-specific for further consideration as a biocontrol agent of exotic Ludwigia spp. in the USA and further testing is not warranted.


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.


Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2545
Author(s):  
Kaitlynn Lavallee ◽  
Pushpa Gautam Soti ◽  
Hansapani Rodrigo ◽  
Rupesh Kariyat ◽  
Alexis Racelis

The incorporation of native plant species is central to restoration efforts, but this is often limited by both the availability of seeds and the relatively low viability and germination rates of commercially available seeds. Although pre-sowing treatments are commonly used to improve germination rates of seeds, the efficacy of these treatments is found to vary across species. In this study, we tested how four pre-sow treatments (physical scarification, acid scarification, cold stratification, and aerated hydropriming) affected the viability and seed germination rates of 12 commercially available plant species native to south Texas and commonly used in restoration efforts. Our results show that the viability of the seeds have a wide range, from 78% to 1.25%. Similarly, the total germination rate ranged from 62% to 0%. We found that pre-sowing treatments accelerated the germination rate in 9 of 12 plant species tested, but the effect varied by treatment. Collectively, our results identify various methods to achieve the best germination rates for native plants of south Texas, to help improve restoration efforts across the region.


2010 ◽  
Vol 100 (5) ◽  
pp. 501-510 ◽  
Author(s):  
N.A. Schellhorn ◽  
R.V. Glatz ◽  
G.M. Wood

AbstractInteractions among insect pests, crops and weeds are well recognised. In fact, the elimination of weed hosts outside of the crop is a common practice to control many insect-vectored viruses. However, little is known about interactions among insect pests, crops and native vegetation, and whether native plants may be used to revegetate areas where weed hosts have been eliminated as part of horticultural management regimes. We used the Northern Adelaide Plains horticultural region (South Australia, Australia) as a model system to study the potential of various plant taxa in hosting four pest thrips (three exotic, one native; Frankliniella occidentalis, F. schultzei, Thrips tabaci and T. imaginis) when located adjacent to, and distant from, horticultural crops. Flower funnels were used for standardised sampling of thrips on flowers from 19 exotic weed and 12 native plant species, representing 13 and three families, respectively. Flowers were sampled monthly over a year, and statistical analyses were performed to identify significant determinants of probability of thrips occurrence and density. Plant family was found to significantly influence both measures for each thrips species. In addition, crop proximity influenced the probability of occurrence for the two Frankliniella species (but only influenced density of the key pest F. occidentalis), and season influenced density of all four pest thrips. All native plant species tested had a low likelihood of hosting the three exotic thrips species. Overall, results suggest that judicious choice of surrounding vegetation has potential to be an important component of integrated pest management (IPM) while increasing biodiversity conservation.


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.


2008 ◽  
Vol 26 (2) ◽  
pp. 109-114 ◽  
Author(s):  
Yousef R. Zadegan ◽  
Bridget K. Behe ◽  
Robert Gough

Abstract In a preliminary study, consumer perceptions of native plants in traditional and naturalistic settings was investigated. In Montana, 361 participants in an internet study reported their familiarity with both woody and herbaceous native plant species. Additional data were collected to determine their perceptions of native plants used in naturalistic designs through a conjoint study. Nearly half of the study participants recognized or had purchased most of the native plants shown in photographs. Results of the conjoint study showed that participants placed the greatest relative importance (62%) on landscape style as the most important factor in landscape design. They also preferred a naturalistic style over a more traditional style and mixed plant species to single species. Across all comparisons, the high relative importance of landscape style remained constant and was consistent with prior studies. Plant material (21.9%) and species diversity (16.2%) were half the relative importance of design style and remained relatively consistent through most comparisons. Even among those participants not familiar with native plants and those who had not purchased native plants, native plants were preferred in the landscapes. The demand for native plants may be reaching a critical stage for both commercial growers and the landscape profession. Although this study was limited to one state, results show that consumer interest is present and further investigation is warranted.


2007 ◽  
Vol 17 (1) ◽  
pp. 78-81 ◽  
Author(s):  
Robert F. Brzuszek ◽  
Richard L. Harkess ◽  
Susan J. Mulley

In their efforts to provide better land stewardship and management, landscape architects are increasingly addressing site ecology in a wide variety of project types. From urban developments to rural properties, designers are using more sustainable design and management techniques, which include the expanded use of regional native plants. This survey study explores the use of native plants by landscape architects in the southeastern United States. Survey results show that southeastern United States designers are using a significant proportion of regional native plant species in their project specifications. Rather than using native plants strictly for conservation measures, landscape architects have found local species to be better suited to difficult or unique site conditions. The findings show that there is potential for expansion in the production and marketing of plant species indigenous to the southeastern United States.


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.


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