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1553 KiB

Open AccessArticle

Aboveground Biomass of Glossy Buckthorn is Similar in Open and Understory Environments but Architectural Strategy Differs

by Caroline Hamelin, Daniel Gagnon and Benoit Truax

Forests 2015, 6(4), 1083-1093; https://doi.org/10.3390/f6041083 - 8 Apr 2015

Cited by 14 | Viewed by 6731

Abstract

The exotic shrub glossy buckthorn (Frangula alnus) is a great concern among forest managers because it invades both open and shaded environments. To evaluate if buckthorn grows similarly across light environments, and if adopting different shapes contributes to an efficient use [...] Read more.

The exotic shrub glossy buckthorn (Frangula alnus) is a great concern among forest managers because it invades both open and shaded environments. To evaluate if buckthorn grows similarly across light environments, and if adopting different shapes contributes to an efficient use of light, we compared buckthorns growing in an open field and in the understory of a mature hybrid poplar plantation. For a given age, the relationships describing aboveground biomass of buckthorns in the open field and in the plantation were not significantly different. However, we observed a significant difference between the diameter-height relationships in the two environments. These results suggest a change in buckthorn’s architecture, depending on the light environment in which it grows. Buckthorn adopts either an arborescent shape under a tree canopy, or a shrubby shape in an open field, to optimally capture the light available. This architectural plasticity helps explain a similar invasion success for glossy buckthorn growing in both open and shaded environments, at least up to the canopy closure level of the plantation used for this study. Full article

(This article belongs to the Special Issue Exotic and Invasive Plant Species Impacting Forests)

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685 KiB

Open AccessArticle

Invasive Plant Species in the National Parks of Vietnam

by Dang Thanh Tan, Pham Quang Thu and Bernard Dell

Forests 2012, 3(4), 997-1016; https://doi.org/10.3390/f3040997 - 30 Oct 2012

Cited by 28 | Viewed by 12015

Abstract

The impact of invasive plant species in national parks and forests in Vietnam is undocumented and management plans have yet to be developed. Ten national parks, ranging from uncut to degraded forests located throughout Vietnam, were surveyed for invasive plant species. Transects were [...] Read more.

The impact of invasive plant species in national parks and forests in Vietnam is undocumented and management plans have yet to be developed. Ten national parks, ranging from uncut to degraded forests located throughout Vietnam, were surveyed for invasive plant species. Transects were set up along roads, trails where local people access park areas, and also tracks through natural forest. Of 134 exotic weeds, 25 were classified as invasive species and the number of invasive species ranged from 8 to 15 per park. An assessment of the risk of invasive species was made for three national parks based on an invasive species assessment protocol. Examples of highly invasive species were Chromolaena odorata and Mimosa diplotricha in Cat Ba National Park (island evergreen secondary forest over limestone); Mimosa pigra, Panicum repens and Eichhornia crassipes in Tram Chim National Park (lowland wetland forest dominated by melaleuca); and C. odorata, Mikania micrantha and M. diplotricha in Son Tra Nature Conservation area (peninsula evergreen secondary forest). Strategies to monitor and manage invasive weeds in forests and national parks in Vietnam are outlined. Full article

(This article belongs to the Special Issue Exotic and Invasive Plant Species Impacting Forests)

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302 KiB

Open AccessArticle

The Sign and Strength of Plant-Soil Feedback for the Invasive Shrub, Lonicera maackii, Varies in Different Soils

by Kelly Schradin and Don Cipollini

Forests 2012, 3(4), 903-922; https://doi.org/10.3390/f3040903 - 16 Oct 2012

Cited by 14 | Viewed by 7537

Abstract

Plants alter soil characteristics causing changes in their subsequent growth resulting in positive or negative feedback on both their own fitness and that of other plants. In a greenhouse study, we investigated whether the sign and strength of feedback changed across two distinct [...] Read more.

Plants alter soil characteristics causing changes in their subsequent growth resulting in positive or negative feedback on both their own fitness and that of other plants. In a greenhouse study, we investigated whether the sign and strength of feedback changed across two distinct soil types, and whether effects were due to shifts in biotic or abiotic soil traits. Using soils from two different locations, we examined growth of the exotic invasive shrub, Lonicera maackii and the related native shrub, Diervilla lonicera, in unconditioned soils and in soils conditioned by previous growth of L. maackii, D. lonicera, and Fraxinus pennsylvanica. In a sandy acidic soil, L. maackii showed positive feedback in unsterilized soils, but its growth decreased and positive feedback became negative with sterilization in this soil. In a loamy circumneutral soil, L. maackii displayed neutral to negative feedback in unsterilized soils, but sterilization significantly increased growth in all conditioning treatments and caused feedback to become strongly negative. Native D. lonicera displayed negative feedback in unsterilized soil of both the sandy and loamy types, but sterilization either eliminated or reversed feedback relationships. Soil conditioning by L. maackii and F. pennsylvanica had very similar feedbacks on L. maackii and D. lonicera. While some abiotic soil traits varied across soil types and were affected by conditioning, soil biota sensitive to sterilization were apparently important mediators of both positive and negative feedback effects. Full article

(This article belongs to the Special Issue Exotic and Invasive Plant Species Impacting Forests)

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144 KiB

Open AccessCommunication

Plant Invasions: Symptoms and Contributors Rather Than Causes of Environmental Degradation

by Vic Jurskis

Forests 2012, 3(4), 896-902; https://doi.org/10.3390/f3040896 - 8 Oct 2012

Cited by 5 | Viewed by 5972

Abstract

Native or exotic woody plants can proliferate in dry and moist eucalypt ecosystems shading out many other native species, contributing to chronic decline of eucalypts and reinforcing unnatural fire regimes and nutrient cycling processes. Whether native or exotic, they proliferate as a consequence [...] Read more.

Native or exotic woody plants can proliferate in dry and moist eucalypt ecosystems shading out many other native species, contributing to chronic decline of eucalypts and reinforcing unnatural fire regimes and nutrient cycling processes. Whether native or exotic, they proliferate as a consequence of disturbances which impact directly on these ecosystems. The most extensive ongoing disturbance since European occupation of Australia has been the disruption of frequent mild burning by humans. This burning maintained dynamically stable nutrient cycling processes and a competitive balance in dry and moist eucalypt systems and prevented plant “invasions”. Full article

(This article belongs to the Special Issue Exotic and Invasive Plant Species Impacting Forests)

586 KiB

Open AccessArticle

Response of the Invasive Grass Imperata cylindrica to Disturbance in the Southeastern Forests, USA

by Eric J. Holzmueller and Shibu Jose

Forests 2012, 3(4), 853-863; https://doi.org/10.3390/f3040853 - 26 Sep 2012

Cited by 24 | Viewed by 7297

Abstract

Imperata cylindrica is an invasive plant species that threatens diversity and forest productivity in southeastern ecosystems. We examined the effects of disturbance events, particularly fire and hurricane/salvage harvesting, to determine the effects on I. cylindrica abundance in longleaf pine (Pinus palustris) [...] Read more.

Imperata cylindrica is an invasive plant species that threatens diversity and forest productivity in southeastern ecosystems. We examined the effects of disturbance events, particularly fire and hurricane/salvage harvesting, to determine the effects on I. cylindrica abundance in longleaf pine (Pinus palustris) forests in the Florida panhandle. Areas that were burned or had greater biomass removal following a hurricane had a greater number of I. cylindrica patches and larger patch size. These results highlight the importance of disturbance events on expanding invasive species populations in this region and are likely applicable for other invasive species as well. Monitoring and treatment should follow disturbance events to ensure that invasive species populations do not exceed unmanageable levels. Full article

(This article belongs to the Special Issue Exotic and Invasive Plant Species Impacting Forests)

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589 KiB

Open AccessArticle

Habitat Modeling of Alien Plant Species at Varying Levels of Occupancy

by Dawn Lemke and Jennifer A. Brown

Forests 2012, 3(3), 799-817; https://doi.org/10.3390/f3030799 - 7 Sep 2012

Cited by 14 | Viewed by 7416

Abstract

Distribution models of invasive plants are very useful tools for conservation management. There are challenges in modeling expanding populations, especially in a dynamic environment, and when data are limited. In this paper, predictive habitat models were assessed for three invasive plant species, at [...] Read more.

Distribution models of invasive plants are very useful tools for conservation management. There are challenges in modeling expanding populations, especially in a dynamic environment, and when data are limited. In this paper, predictive habitat models were assessed for three invasive plant species, at differing levels of occurrence, using two different habitat modeling techniques: logistic regression and maximum entropy. The influence of disturbance, spatial and temporal heterogeneity, and other landscape characteristics is assessed by creating regional level models based on occurrence records from the USDA Forest Service’s Forest Inventory and Analysis database. Logistic regression and maximum entropy models were assessed independently. Ensemble models were developed to combine the predictions of the two analysis approaches to obtain a more robust prediction estimate. All species had strong models with Area Under the receiver operator Curve (AUC) of >0.75. The species with the highest occurrence, Ligustrum spp., had the greatest agreement between the models (93%). Lolium arundinaceum had the most disagreement between models at 33% and the lowest AUC values. Overall, the strength of integrative modeling in assessing and understanding habitat modeling was demonstrated. Full article

(This article belongs to the Special Issue Exotic and Invasive Plant Species Impacting Forests)

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219 KiB

Open AccessArticle

Arboricultural Introductions and Long-Term Changes for Invasive Woody Plants in Remnant Urban Forests

by Robert E. Loeb

Forests 2012, 3(3), 745-763; https://doi.org/10.3390/f3030745 - 27 Aug 2012

Cited by 7 | Viewed by 6893

Abstract

Long-term changes for invasive trees and shrubs presence in 16 floras encompassing four remnant urban forests of the coastal northeastern United States were examined for relationships with arboricultural introductions’ residence time and planting intensity, and state level recognition of regional invasive woody taxa. [...] Read more.

Long-term changes for invasive trees and shrubs presence in 16 floras encompassing four remnant urban forests of the coastal northeastern United States were examined for relationships with arboricultural introductions’ residence time and planting intensity, and state level recognition of regional invasive woody taxa. The number of invasive woody taxa significantly increased over the period 1818 to 2011 which encompasses the 16 floras. No significant Pearson product moment correlations were found for residence time as the year of introduction to arboriculture with presence in the 16 floras as well as with the 4 most recent floras. In contrast to residence time, planting intensity from the North American flora and two botanical gardens floras of the region from 1811 to 1818 and New York and Philadelphia parks floras from 1857 to 1903 did have significant correlations with the 16 floras and the 4 most recent floras. State level recognition of regional invasive woody taxa showed significant correlations with presence in all 16 floras as well as the 4 most recent floras. Monitoring for range expansion by the regional invasive woody taxa is essential because only 18% of the 98 taxa are present in all 4 of the most recent floras. Full article

(This article belongs to the Special Issue Exotic and Invasive Plant Species Impacting Forests)

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Graphical abstract

173 KiB

Open AccessArticle

Efficacy of Treatments against Garlic Mustard (Alliaria petiolata) and Effects on Forest Understory Plant Diversity

by Lindsey M. Shartell, Linda M. Nagel and Andrew J. Storer

Forests 2012, 3(3), 605-613; https://doi.org/10.3390/f3030605 - 3 Aug 2012

Cited by 6 | Viewed by 7245

Abstract

Garlic mustard, an invasive exotic biennial herb, has been identified in the Upper Peninsula of Michigan, but is not yet widely distributed. We tested the effectiveness and impact of management tools for garlic mustard in northern hardwood forests. Six treatment types (no treatment [...] Read more.

Garlic mustard, an invasive exotic biennial herb, has been identified in the Upper Peninsula of Michigan, but is not yet widely distributed. We tested the effectiveness and impact of management tools for garlic mustard in northern hardwood forests. Six treatment types (no treatment control, hand-pull, herbicide, hand-pull/herbicide, scorch, and hand-pull/scorch) were applied within a northern hardwood forest invaded by garlic mustard. We sampled understory vegetation within plots to compare garlic mustard abundance (distinguishing first and second year plants) and native plant diversity before and after treatment. Results immediately following treatment indicated that garlic mustard seedling abundance was significantly reduced by herbicide, hand-pull/herbicide, scorch, and hand-pull/scorch treatments, and that adult abundance was reduced by all treatments. However, sampling of treatment sites one year later showed an increase in seedling abundance in herbicide and hand-pull/herbicide plots. Adult garlic mustard abundance after one year was lower than the control with the exception of the hand-pull plots where adult abundance did not differ. After one year, understory species richness and Shannon’s Diversity were lower in the herbicide and pull/herbicide treatments. Based on these results, we conclude that single-year treatment of garlic mustard with hand-pulling, herbicide, and/or scorching is ineffective in reducing garlic mustard abundance and may inadvertently increase the success of garlic mustard, while negatively impacting native understory species. Full article

(This article belongs to the Special Issue Exotic and Invasive Plant Species Impacting Forests)

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373 KiB

Open AccessArticle

Potential Range Expansion of Japanese Honeysuckle (Lonicera japonica Thunb.) in Southern U.S. Forestlands

by Hsiao-Hsuan Wang, Carissa L. Wonkka, William E. Grant and William E. Rogers

Forests 2012, 3(3), 573-590; https://doi.org/10.3390/f3030573 - 27 Jul 2012

Cited by 11 | Viewed by 10178

Abstract

Japanese honeysuckle is one of the most aggressive invasive vines in forestlands of the southern United States. We analyzed field data collected by the U.S. Forest Service to identify potential determinants of invasion and to predict likelihood of further invasion under a variety [...] Read more.

Japanese honeysuckle is one of the most aggressive invasive vines in forestlands of the southern United States. We analyzed field data collected by the U.S. Forest Service to identify potential determinants of invasion and to predict likelihood of further invasion under a variety of possible management strategies. Results of logistic regression, which classified 74% of the field plots correctly with regard to species presence and absence, indicated probability of invasion is correlated positively with adjacency to water bodies, temperature, site productivity, species diversity, and private land ownership, and is correlated negatively with slope, stand age, artificial regeneration, distance to the nearest road, and fire disturbance. Habitats most at risk to further invasion under current conditions occur throughout Mississippi, stretching northward across western Tennessee and western Kentucky, westward across southern Arkansas, eastward across north-central Alabama, and also occur in several counties scattered within Virginia. Invasion likelihoods could be increased by global climate change and reduced most by conversion to public land ownership, followed by artificial regeneration, and fire disturbance. While conversion of land ownership may not be feasible, this result suggests the opportunity for decreasing the likelihood of invasions on private lands via using selected management practices. Full article

(This article belongs to the Special Issue Exotic and Invasive Plant Species Impacting Forests)

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130 KiB

Open AccessArticle

A Comparison of Invasive Acer platanoides and Native A. saccharum First-Year Seedlings: Growth, Biomass Distribution and the Influence of Ecological Factors in a Forest Understory

by Marie Lapointe and Jacques Brisson

Forests 2012, 3(2), 190-206; https://doi.org/10.3390/f3020190 - 3 May 2012

Cited by 8 | Viewed by 8461

Abstract

Invasive shade tolerant species can have profound and long-lasting detrimental effects even on previously undisturbed forests. In North American forests, the invasive Acer platanoides is capable of dominating the understory where it could displace the native Acer saccharum. To understand the relative [...] Read more.

Invasive shade tolerant species can have profound and long-lasting detrimental effects even on previously undisturbed forests. In North American forests, the invasive Acer platanoides is capable of dominating the understory where it could displace the native Acer saccharum. To understand the relative importance of various ecological factors in a forest understory on their establishment, we transplanted A. platanoides and A. saccharum seedlings in an urban sugar maple forest understory and their growth and survival were compared over a growing season. Seedlings did not differ in height, but biomass growth and assimilation rates were twice as high for the invasive species. Ecological variables accounted for only 23–24% of variation in growth. Seedlings of A. platanoides appeared to capture light more efficiently, with over 150% greater foliage biomass and surface area. A. saccharum seedlings were more negatively affected by herbivory. The more robust A. platanoides seedlings presented characteristics that could allow them to better grow and survive in shaded understories than their native congeners. Full article

(This article belongs to the Special Issue Exotic and Invasive Plant Species Impacting Forests)

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Review

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199 KiB

Open AccessReview

Relationship between Invasive Plant Species and Forest Fauna in Eastern North America

by Stephanie J. Hayes and Eric J. Holzmueller

Forests 2012, 3(3), 840-852; https://doi.org/10.3390/f3030840 - 12 Sep 2012

Cited by 16 | Viewed by 8380

Abstract

Invasive plant species have long been known to cause extensive damage, both economically and ecologically, to native ecosystems. They have historically been introduced by the public, both intentional and not, for a variety of reasons. Many of the woody shrubs, such as Lonicera [...] Read more.

Invasive plant species have long been known to cause extensive damage, both economically and ecologically, to native ecosystems. They have historically been introduced by the public, both intentional and not, for a variety of reasons. Many of the woody shrubs, such as Lonicera maackii and Rosa multiflora were introduced for wildlife cover, forage, and ornamental value. These invasives have quickly out-competed native flora, in many cases drastically impacting and changing the environment they inhabit. In this review, chosen species characteristics have been described, their pathway to invasion explained, and their impacts to native wildlife highlighted. Based on a review of the scientific literature, we determined that not all effects by invasive plants are negative. Many positive impacts can be seen throughout the literature, such as native frogs utilizing Microstegium vimineum for cover and nesting habitat. However, some important invasive plant species were not included in this review due to a lack of literature on the subject of the effects on fauna. While much is known about their economic impact and the impact on native plant species, additional work needs to be done in the field of wildlife research to determine current impacts and future implications of non-native, invasive plants on native fauna. Full article

(This article belongs to the Special Issue Exotic and Invasive Plant Species Impacting Forests)

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