scholarly journals Evaluating Landscape Performance of Six Native Shrubs as Alternatives to Invasive Exotics

2013 ◽  
Vol 23 (1) ◽  
pp. 119-125 ◽  
Author(s):  
Jessica D. Lubell

There is increased interest in using native plant alternatives to invasive species for landscaping. Several invasive shrubs are used extensively in landscaping since they perform well in challenging landscapes, such as parking lot island plantings, which are dry, nutrient-poor, and sun and heat exposed. This study evaluated the landscape suitability of six underused Connecticut native shrubs [american filbert (Corylus americana), buttonbush (Cephalanthus occidentalis), northern bush honeysuckle (Diervilla lonicera), steeplebush (Spiraea tomentosa), sweet fern (Comptonia peregrina), and sweet gale (Myrica gale)] by planting them in a large commuter parking lot on the University of Connecticut (UConn) campus in Storrs. Two nonnative invasive species, ‘Crimson Pygmy’ japanese barberry (Berberis thunbergii) and ‘Compactus’ winged euonymus (Euonymus alatus), were also planted as controls. Buttonbush, sweet fern, and sweet gale performed as well as controls and had aesthetic quality index (AQI) ratings similar to controls throughout the study, which spanned three growing seasons. These findings were surprising for buttonbush and sweet gale, which are found in the wild occupying predominantly wet areas. Buttonbush plants readily established at the site as indicated by a 930% increase in plant size over the first growing season. Sweet fern and sweet gale produced attractive, dense, and uniform mounds consistently throughout the study. Northern bush honeysuckle and american filbert were slower to establish, but by the second and third year, respectively, plants were highly attractive and had AQI ratings similar to controls. Despite its attractive floral display, steeplebush performed poorly and developed powdery mildew (Sphaerotheca) symptoms in the first and second years, which contributed to a lower AQI compared with controls. Aesthetic quality for american filbert, buttonbush, and steeplebush was reduced because of variation resulting from seed propagation. For certain native species, plants received from the nursery were not robust, which may have had a greater influence on establishment and early performance than their inherent landscape adaptability. This study identified five underused native shrubs that are adaptable and able to replace invasive plants in landscapes.

2015 ◽  
Vol 25 (2) ◽  
pp. 171-176 ◽  
Author(s):  
Pragati Shrestha ◽  
Jessica D. Lubell

Nursery and landscape professionals are interested in white-tailed deer (Odocoileus virginianus)–resistant native plants to replace invasive species used in difficult landscape sites, such as parking lot islands, which are dry, nutrient-poor, and exposed to sun and heat. Eight native shrubs [creeping sand cherry (Prunus pumila var. depressa), elderberry (Sambucus canadensis), gray dogwood (Cornus racemosa), highbush blueberry (Vaccinium corymbosum), round leaf dogwood (Cornus rugosa), northern spicebush (Lindera benzoin), sweetbells (Eubotrys racemosa), and virginia rose (Rosa virginiana)] were planted in a large commuter parking lot on the University of Connecticut campus to evaluate their suitability for use in difficult landscapes. The non-native, invasive shrubs ‘Compactus’ winged euonymus (Euonymus alatus) and ‘Crimson Pygmy’ japanese barberry (Berberis thunbergii) were also planted as controls representing non-native species typically planted in such sites. Aesthetic quality ratings for sweetbells matched the controls (rating of 4.5 out of 5.0) and plants exhibited a high level of white-tailed deer resistance. Virgina rose and creeping sand cherry had similar aesthetic quality to controls, despite light grazing of plants by white-tailed deer. Elderberry was damaged by moderate white-tailed deer grazing and snow load, but plants regenerated to 485% of initial size in one growing season with white-tailed deer exclusion. Gray dogwood, round leaf dogwood, and northern spicebush exhibited the least resistance to white-tailed deer grazing. Both dogwood species had lower aesthetic quality than the controls, and round leaf dogwood had the lowest survival rate (68%) after 2 years. However, several individuals of gray dogwood, round leaf dogwood, and northern spicebush that were less heavily damaged by white-tailed deer grew into attractive shrubs after white-tailed deer exclusion. Highbush blueberry had significantly lower aesthetic quality than controls and only 75% survival after 2 years, indicating that this species is an unsuitable replacement for invasives in difficult landscape sites. This study identified the underused native shrubs sweetbells, virginia rose, and creeping sand cherry as suitable replacements for invasives in difficult landscape sites with white-tailed deer pressure.


PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0237894
Author(s):  
Amy E. Kendig ◽  
Vida J. Svahnström ◽  
Ashish Adhikari ◽  
Philip F. Harmon ◽  
S. Luke Flory

Infectious diseases and invasive species can be strong drivers of biological systems that may interact to shift plant community composition. For example, disease can modify resource competition between invasive and native species. Invasive species tend to interact with a diversity of native species, and it is unclear how native species differ in response to disease-mediated competition with invasive species. Here, we quantified the biomass responses of three native North American grass species (Dichanthelium clandestinum, Elymus virginicus, and Eragrostis spectabilis) to disease-mediated competition with the non-native invasive grass Microstegium vimineum. The foliar fungal pathogen Bipolaris gigantea has recently emerged in Microstegium populations, causing a leaf spot disease that reduces Microstegium biomass and seed production. In a greenhouse experiment, we examined the effects of B. gigantea inoculation on two components of competitive ability for each native species: growth in the absence of competition and biomass responses to increasing densities of Microstegium. Bipolaris gigantea inoculation affected each of the three native species in unique ways, by increasing (Dichanthelium), decreasing (Elymus), or not changing (Eragrostis) their growth in the absence of competition relative to mock inoculation. Bipolaris gigantea inoculation did not, however, affect Microstegium biomass or mediate the effect of Microstegium density on native plant biomass. Thus, B. gigantea had species-specific effects on native plant competition with Microstegium through species-specific biomass responses to B. gigantea inoculation, but not through modified responses to Microstegium density. Our results suggest that disease may uniquely modify competitive interactions between invasive and native plants for different native plant species.


2012 ◽  
Vol 18 (2) ◽  
pp. 77 ◽  
Author(s):  
Heather Parks ◽  
Kyle Clifton ◽  
Lauren Best ◽  
Bridget Johnson

PEST-PROOF (exclusion) fences are designed to prevent non-native, predatory and pest species from repopulating an area set aside to protect vulnerable native plant and animal species. Pest-proof fencing provides security from invasive species, but can isolate the native species enclosed within. On one hand, some rare native species exist on the mainland due to the pest-free status achieved through the use of exclusion fences. On the other hand, these reintroduced populations are now isolated a situation where they would not be found naturally (Jamieson et al. 2006). Exclusion fences must be constantly maintained or the sanctuary risks reinvasion. An important question for conservation biologists and managers to answer is therefore — when is exclusion fencing the best option for protecting native species from introduced pests? We have drawn our examples from New Zealand and Australia where progress has been made with regard to the design and utilization of exclusion fences.


2013 ◽  
Vol 6 (4) ◽  
pp. 459-469 ◽  
Author(s):  
Jeffrey S. Ward ◽  
Scott C. Williams ◽  
Thomas E. Worthley

AbstractTwo factors that can degrade native plant community composition and structure, and hinder restoration efforts, are invasive species and chronic overbrowsing by ungulates such as white-tailed deer. Beginning in 2007, the effectiveness, costs, and impacts of Japanese barberry control treatments and herbivory on nonnative and native plant communities was examined at eight study areas over 4 to 5 yr. Prescribed burning and mechanical mowing by wood shredder or brush saw were utilized as initial treatments to reduce the aboveground portion of established barberry and were equally effective. Without a follow-up treatment, barberry had recovered to 56 to 81% of pretreatment levels 50 to 62 mo after initial treatment. Follow-up treatments in mid-summer to kill new sprouts included directed heating and foliar herbicide applications. Relative to untreated controls, follow-up treatments lowered barberry cover 50 to 62 mo after initial treatment by at least 72%. Although all follow-up treatments were equally effective, the labor cost of directed heating was four times higher than for herbicide applications. Follow-up treatment type (directed heating vs. herbicide) had minimal impact on species other than barberry. White-tailed deer herbivory had a larger impact on other species than did barberry control treatments. Native grass and fern cover was higher outside of exclosures. Areas inside exclosures had higher cover of Oriental bittersweet and multiflora rose, but not Japanese barberry. Thus, recovery of native communities will require more than simply removing the dominant invasive species where deer densities are high. Excellent reduction of Japanese barberry cover can be achieved using either directed heating or herbicides as follow-up treatments in a two-step process, but other invasive plants may become a problem when barberry is removed if deer populations are low.


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 18 (2) ◽  
pp. 123 ◽  
Author(s):  
E Reddy ◽  
D H Van Vuren ◽  
P G Scowcroft ◽  
J B Kauffman ◽  
L Perry

Seven exclosure sites located on Mauna Kea, Hawaii and established in the 1960s and 70s were sampled to characterize long-term response of the mamane (Sophora chrysophylla) forest to protection from feral sheep grazing, and to assess impacts of non-native plant species and recurrent sheep presence on forest recovery. The forest provides essential habitat for an endangered bird, the palila (Loxoides bailleui). Vegetation was sampled inside exclosures during 1972–1976, 1998, and 2009, and also outside exclosures during 2009. Patterns of response varied among exclosures, but overall, mamane trees and native shrubs showed increasing cover between the 1970s and 1998, then a slowed rate of increase in cover or a decline between 1998 and 2009. Cover of native herbaceous vegetation showed variable trends between the 1970s and 1998, and then appeared to decline between 1998 and 2009. Mamane height class distributions inside exclosures indicated that recruitment was initially high but then declined as heights shifted toward larger size classes, and presumably an older age distribution. We found limited evidence of a negative effect of non-native species on forest regrowth, but the effect was not consistent over time or among sites. Recurrent sheep presence outside exclosures negatively affected mamane canopy density and perhaps tree density at all sites, and mamane condition at some sites. Our results indicate that the mamane forest has shown substantial regrowth inside exclosures at some sites, especially those protected the longest. However, these exclosures represent a small portion of the mamane forest. Sheep presence continues to impact mamane recovery outside exclosures, and thus habitat quality for the palila.


Author(s):  
Leeladarshini Sujeeun ◽  
Sean C. Thomas

Many tropical invasive species have allelopathic effects that contribute to their success in native plant communities. Pyrolyzed biomass (“biochar”) can sorb toxic compounds, including allelochemicals produced by invasive plants, potentially reducing their inhibitory effects on native species. Strawberry guava (Psidium cattleianum) is among the most important allelopathic invasive species in tropical islands and recognized as the most serious invasive species threat in the global biodiversity hotspot of Mauritius. We investigated the effects of additions of locally produced biochar on native tree species in a field experiment conducted in areas invaded by strawberry guava within Mauritius’ largest national park. Growth and survivorship of native tree species were monitored over 2 ½ years in plots subjected to four treatments: non-weeded, weeded, weeded + 25 t/ha biochar and weeded + 50 t/ha biochar. Native tree growth and survivorship were strongly suppressed by strawberry guava. Biochar treatments dramatically increased native tree performance, with more than a doubling in growth, and substantially increased native tree survivorship and species diversity, while suppressing strawberry guava regeneration, consistent with growth-promoting properties and sorption of allelochemicals. We conclude that biochars, including “sustainable biochars” produced from locally accessible biomass using low-tech pyrolysis systems, have considerable potential to counteract effects of allelopathic invaders and increase the capacity for native species regeneration in tropical island ecosystems.


Author(s):  
Lohengrin A. Cavieres ◽  
◽  

Biological invasions are one the most important drivers of the current environmental changes generating important biodiversity losses. Although several hypotheses have been proposed to understand the mechanisms underpinning biological invasions, most of them relate to negative interactions among native and invasive species, where the capacity for many invasive species to reduce diversity is often attributed to a greater competitiveness. However, neighbouring species can also show facilitative interactions, where the presence of one species can facilitate another directly by improving environmental conditions or indirectly through negative effects on a third party species. This chapter reviews the scientific literature on plant invasion, seeking examples of where facilitative interactions either among native and non-native plant species or among non-native species were demonstrated. There are several examples of native species that directly facilitate a non-native species, while examples of native species having a negative effect either on a native or a non-native species that compete with a target non-native, generating a net indirect facilitative effect of the native on the target non-native, are less numerous. Direct facilitation among non-native species has been reported as part of the 'invasional meltdown' phenomenon (Chapter 8, this volume). There are cases where non-native species can have a negative effect on a native species that competes with a target non-native, generating a net indirect facilitative effect among the non-natives. Finally, a non-native species can have a direct facilitative effect on native species, which might have important implications in restoration.


2012 ◽  
Vol 5 (4) ◽  
pp. 494-505 ◽  
Author(s):  
Nicholas R. Jordan ◽  
Laura Aldrich-Wolfe ◽  
Sheri C. Huerd ◽  
Diane L. Larson ◽  
Gary Muehlbauer

AbstractDiversified grasslands that contain native plant species can produce biofuels, support sustainable grazing systems, and produce other ecosystem services. However, ecosystem service production can be disrupted by invasion of exotic perennial plants, and these plants can have soil-microbial “legacies” that may interfere with establishment and maintenance of diversified grasslands even after effective management of the invasive species. The nature of such legacies is not well understood, but may involve suppression of mutualisms between native species and soil microbes. In this study, we tested the hypotheses that legacy effects of invasive species change colonization rates, diversity, and composition of arbuscular-mycorrhizal fungi (AMF) associated with seedlings of co-occurring invasive and native grassland species. In a glasshouse, experimental soils were conditioned by cultivating three invasive grassland perennials, three native grassland perennials, and a native perennial mixture. Each was grown separately through three cycles of growth, after which we used T-RFLP analysis to characterize AMF associations of seedlings of six native perennial and six invasive perennial species grown in these soils. Legacy effects of soil conditioning by invasive species did not affect AMF richness in seedling roots, but did affect AMF colonization rates and the taxonomic composition of mycorrhizal associations in seedling roots. Moreover, native species were more heavily colonized by AMF and roots of native species had greater AMF richness (number of AMF operational taxonomic units per seedling) than did invasive species. The invasive species used to condition soil in this experiment have been shown to have legacy effects on biomass of native seedlings, reducing their growth in this and a previous similar experiment. Therefore, our results suggest that successful plant invaders can have legacies that affect soil-microbial associations of native plants and that these effects can inhibit growth of native plant species in invaded communities.


2019 ◽  
Vol 124 (5) ◽  
pp. 819-827 ◽  
Author(s):  
Xinmin Lu ◽  
Minyan He ◽  
Saichun Tang ◽  
Yuqing Wu ◽  
Xu Shao ◽  
...  

Abstract Background and Aims The strengths of biotic interactions such as herbivory are expected to decrease with increasing latitude for native species. To what extent this applies to invasive species and what the consequences of this variation are for competition among native and invasive species remain unexplored. Here, herbivore impacts on the invasive plant Alternanthera philoxeroides and its competition with the native congener A. sessilis were estimated across latitudes in China. Methods An common garden experiment spanning ten latitudinal degrees was conducted to test how herbivore impacts on A. philoxeroides and A. sessilis, and competition between them change with latitude. In addition, a field survey was conducted from 21°N to 36.8°N to test whether A. philoxeroides invasiveness changes with latitude in nature as a result of variations in herbivory. Key Results In the experiment, A. sessilis cover was significantly higher than A. philoxeroides cover when they competed in the absence of herbivores, but otherwise their cover was comparable at low latitude. However, A. philoxeroides cover was always higher on average than A. sessilis cover at middle latitude. At high latitude, only A. sessilis emerged in the second year. Herbivore abundance decreased with latitude and A. philoxeroides emerged earlier than A. sessilis at middle latitude. In the field survey, the ratio of A. philoxeroides to A. sessilis cover was hump shaped with latitude. Conclusion These results indicate that herbivory may promote A. philoxeroides invasion only at low latitude by altering the outcome of competition in favour of the invader and point to the importance of other factors, such as earlier emergence, in A. philoxeroides invasion at higher latitudes. These results suggest that the key factors promoting plant invasions might change with latitude, highlighting the importance of teasing apart the roles of multiple factors in plant invasions within a biogeographic framework.


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