scholarly journals Closed-Canopy Tropical Forests of Hainan, (China) Are Resilient against Invasive Herbs and Shrubs

Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1596
Author(s):  
Xiaobo Yang ◽  
Long Li ◽  
Xiaobo Lv ◽  
Wenqi Luo ◽  
Donghai Li ◽  
...  
Keyword(s):  
Tropical Forests ◽  
Invasive Plants ◽  
Native Species ◽  
Invasive Plant ◽  
Soil Seed Bank ◽  
Light Availability ◽  
Successional Stage ◽  
Sharp Drop ◽  
Closed Canopy ◽  
Successional Stages

The successful establishment of many plants in tropical forests often depends on species-specific adaptations related to light availability and forest successional stage. Species that are present in early successional stages generally do not occur in later successional stages. In this study, we documented the diversity, distribution, and abundance of terrestrial invasive plants across the (sub)tropical island of Hainan, China, and tested the germination of specific invasive plants in forested environments. In 97 transects positioned randomly across the island, we found nine invasive herb and shrub species were present in all human-modified habitats but not in intact forest interiors. In separate forest-specific transects, we documented a sharp drop in the abundance of invasive plants >5 m into the forest. High numbers of invasive plant seeds germinated from the soil seed bank sampled at the forest edge, but very few seeds germinated from soil sampled any distance into the forest. Finally, in experiments with four focal invasive plant species, overall germination rates were low; and much lower in shaded sites compared to full gap sites. In conclusion, our findings demonstrated that invasive herbs and shrubs do not yet form a serious threat to native species in the closed-canopy forests of Hainan.

scholarly journals SOIL SEED BANK IN SEASONAL SEMIDECIDUOUS FOREST AND ABANDONED PASTURE

2016 ◽  
Vol 40 (6) ◽  
pp. 991-1001 ◽  
Author(s):  
Sustanis Horn Kunz ◽  
Sebastião Venâncio Martins
Keyword(s):  
Seed Bank ◽  
Soil Seed Bank ◽  
Life Forms ◽  
Successional Stage ◽  
Semideciduous Forest ◽  
Regeneration Stage ◽  
Significant Difference ◽  
Successional Stages ◽  
Pasture Area ◽  
Seasonal Semideciduous Forest

ABSTRACT The objective of this study was to characterize the seed bank in the soil of different successional stages of Seasonal Semideciduous Forest and abandoned pasture in order to understand the natural regeneration potential of these areas. At each successional stage, 30 samples of soil were collected in the rainy and dry seasons to evaluate the qualitative heterogeneity of the forest, at the regeneration stage (FEA) forest, intermediate regeneration stage forest (ISF) and pasture (PAS). The species were classified according to the life form, successional group and dispersion syndrome. The number of individuals germinated was significantly higher (p < 0.001) in the ISF and in the rainy season (15,949 individuals). Richness was higher in the pasture area (79 species), with a significant difference only between the environments. Most species are herbaceous (49.5%), pioneers (76.5%) and zoocory was the main dispersion syndrome (49% of species). The results show that seed bank in the fragment of the regeneration advanced stage forest presents the highest resilience potential, since it is formed by different life forms and, mainly, by early and late secondary species.

scholarly journals Niche Models Differentiate Potential Impacts of Two Aquatic Invasive Plant Species on Native Macrophytes

Diversity ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 162
Author(s):  
Michael R. Verhoeven ◽  
Wesley J. Glisson ◽  
Daniel J. Larkin
Keyword(s):  
Native Species ◽  
Invasive Plant ◽  
Environmental Gradients ◽  
Myriophyllum Spicatum ◽  
Light Availability ◽  
Niche Overlap ◽  
Growth Cycle ◽  
Potamogeton Crispus ◽  
Starting Point ◽  
Niche Models

Potamogeton crispus (curlyleaf pondweed) and Myriophyllum spicatum (Eurasian watermilfoil) are widely thought to competitively displace native macrophytes in North America. However, their perceived competitive superiority has not been comprehensively evaluated. Coexistence theory suggests that invader displacement of native species through competitive exclusion is most likely where high niche overlap results in competition for limiting resources. Thus, evaluation of niche similarity can serve as a starting point for predicting the likelihood of invaders having direct competitive impacts on resident species. Across two environmental gradients structuring macrophyte communities—water depth and light availability—both P. crispus and M. spicatum are thought to occupy broad niches. For a third dimension, phenology, the annual growth cycle of M. spicatum is typical of other species, whereas the winter-ephemeral phenology of P. crispus may impart greater niche differentiation and thus lower risk of native species being competitively excluded. Using an unprecedented dataset comprising 3404 plant surveys from Minnesota collected using a common protocol, we modeled niches of 34 species using a probabilistic niche framework. Across each niche dimension, P. crispus had lower overlap with native species than did M. spicatum; this was driven in particular by its distinct phenology. These results suggest that patterns of dominance seen in P. crispus and M. spicatum have likely arisen through different mechanisms, and that direct competition with native species is less likely for P. crispus than M. spicatum. This research highlights the utility of fine-scale, abundance-based niche models for predicting invader impacts.

scholarly journals Seasonal and successional dynamics of size-dependent plant demographic rates in a tropical dry forest

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9636
Author(s):  
Irving Saenz-Pedroza ◽  
Richard Feldman ◽  
Casandra Reyes-García ◽  
Jorge A. Meave ◽  
Luz Maria Calvo-Irabien ◽  
...  
Keyword(s):  
Climate Change ◽  
Tropical Forests ◽  
Dry Season ◽  
Dry Forest ◽  
Species Density ◽  
Wet Season ◽  
Successional Stage ◽  
Size Dependent ◽  
Demographic Rates ◽  
Successional Stages

Tropical forests are globally important for biodiversity conservation and climate change mitigation but are being converted to other land uses. Conversion of seasonally dry tropical forests (SDTF) is particularly high while their protection is low. Secondary succession allows forests to recover their structure, diversity and composition after conversion and subsequent abandonment and is influenced by demographic rates of the constituent species. However, how these rates vary between seasons for different plant sizes at different successional stages in SDTF is not known. The effect of seasonal drought may be more severe early in succession, when temperature and radiation are high, while competition and density-dependent processes may be more important at later stages, when vegetation is tall and dense. Besides, the effects of seasonality and successional stage may vary with plant size. Large plants can better compete with small plants for limiting resources and may also have a greater capacity to withstand stress. We asked how size-dependent density, species density, recruitment and mortality varied between seasons and successional stages in a SDTF. We monitored a chronosequence in Yucatan, Mexico, over six years in three 0.1 ha plots in each of three successional stages: early (3–5 years-old), intermediate (18–20 years-old) and advanced (>50 years-old). Recruitment, mortality and species gain and loss rates were calculated from wet and dry season censuses separately for large (diameter > 5 cm) and small (1–5 cm in diameter) plants. We used linear mixed-effects models to assess the effects of successional stage, seasonality and their changes through time on demographic rates and on plant and species density. Seasonality affected demographic rates and density of large plants, which exhibited high wet-season recruitment and species gain rates at the early stage and high wet-season mortality at the intermediate stage, resulting in an increase in plant and species density early in succession followed by a subsequent stabilization. Small plant density decreased steadily after only 5 years of land abandonment, whereas species density increased with successional stage. A decline in species dominance may be responsible for these contrasting patterns. Seasonality, successional stage and their changes through time had a stronger influence on large plants, likely because of large among-plot variation of small plants. Notwithstanding the short duration of our study, our results suggest that climate-change driven decreases in rainy season precipitation may have an influence on successional dynamics in our study forest as strong as, or even stronger than, prolonged or severe droughts during the dry season.

scholarly journals Allelopathy is pervasive in invasive plants

2020 ◽  
Author(s):  
Susan Kalisz ◽  
Stephanie N. Kivlin ◽  
Lalasia Bialic-Murphy
Keyword(s):  
Invasive Species ◽  
Invasive Plants ◽  
Native Species ◽  
Invasive Plant ◽  
Native Plants ◽  
Plant Performance ◽  
Native Plant ◽  
Plant Phylogeny ◽  
Plant Families ◽  
Allelopathic Compounds

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.

Effects of invasive plant patch size and distance on the pollination and reproduction of native boreal plants

Botany ◽  
2016 ◽  
Vol 94 (12) ◽  
pp. 1151-1160 ◽  
Author(s):  
Katie V. Spellman ◽  
Christa P.H. Mulder ◽  
Matthew L. Carlson
Keyword(s):  
Invasive Species ◽  
Seed Production ◽  
Invasive Plants ◽  
Native Species ◽  
Patch Size ◽  
Invasive Plant ◽  
Native Plants ◽  
Invasion Process ◽  
Melilotus Albus ◽  
Boreal Plants

In pollinator-limited ecosystems in the earliest stages of the invasion process, the effects of invasive plants on the pollination and reproduction of co-flowering native plants may be particularly sensitive to the distance between native and non-native plants. Our study tests how the distance from invasive plant patches affects the pollination and reproduction of two native boreal shrubs. We established circular sites with plots of flowering Vaccinium vitis-idaea L. and Rhododendron groenlandicum (Oeder) Kron and Judd spanning from 1 to 40 m from the site center. In 2011 and 2012, we added flowering non-native Melilotus albus Medik. to the center of sites in small patches (40 individuals) or large patches (120 individuals) and left other sites as controls. In some cases, the effects of M. albus were uniform across the 40 m distance, such as the change in V. vitis-idaea seed production when large patches of M. albus were added. In other cases, relationships with distance were found, and changes in percent pollination or seed production occurred most rapidly over the first 10 m from the patch. Our data supports the hypothesis that the detectable impact an invasive species has on the pollination of native species is affected by the spatial scale over which it is evaluated.

scholarly journals Native seed addition as an effective tool for post-invasion restoration

2019 ◽  
Author(s):  
Anna Bucharova ◽  
František Krahulec
Keyword(s):  
Invasive Plants ◽  
Seed Bank ◽  
Native Species ◽  
Invasive Plant ◽  
Control Strategies ◽  
Economic Losses ◽  
Native Grasses ◽  
Policy Makers ◽  
Native Seed ◽  
Rumex Alpinus

AbstractInvasive plant species reduce biodiversity, alter ecosystem processes, and cause economic losses. Control of invasive plants is therefore highly desired by land managers and policy makers. However, invasive plant control strategies frequently fail, partly because management often concentrates only on the eradication of invasive plants and not on revegetation with native species that use the available resources and prevent reinvasion. In this study, we focused on the intracontinental invader Rumex alpinus L., which was introduced by humans from the Alps to the lower mountains of Central Europe, where it has spread to semi-natural meadows, suppresses local biodiversity, and reduces the quality of hay used as cattle fodder. The species can be effectively removed using herbicide, but this leaves behind a persistent seed bank. Without further treatment, the invader rapidly regenerates and reinvades the area. We supplemented the herbicide treatment by adding the seeds of native grasses. Addition of native-seed effectively suppressed the regeneration of the invader from the seed bank, reduced its biomass, and consequently, prevented massive reinvasion. While the invader removal was successful, the restored community remained species-poor because the dense sward of native grasses blocked the regeneration of native forbs from the seed bank. Nevertheless, the addition of native seed proved to be an effective tool in preventing reinvasion after the eradication of the invasive plant.

scholarly journals Invasive Plants with Native Lookalikes: How Mistaken Identities Can Lead to More Significant Plant Invasions and Delay Management

2021 ◽  
pp. 1-10
Author(s):  
S. Christopher Marble ◽  
Stephen H. Brown
Keyword(s):  
Invasive Plants ◽  
Native Species ◽  
Invasive Plant ◽  
Population Expansion ◽  
Plant Invasions ◽  
Plant Management ◽  
Delayed Response ◽  
Native Plant ◽  
Success Rates ◽  
Invasive Plant Management

Plant invasions pose a serious threat to biodiversity, agricultural production, and land value throughout the world. Due to Florida’s unique climate, population expansion, expansive coastline, and number of seaports, the state is especially vulnerable to non-native plant naturalization and spread. Invasive plant management programs were shown to have higher success rates with fewer resources when invasives were managed soon after non-native plants were observed. However, some newly emerging invasive plants may go undetected due to their resemblance with native species or other invasive plants. The objective of this review is to highlight a few key invasive plants in Florida that have native lookalikes. While morphological differences are discussed, the primary goal is to discuss management implications of misidentification and delayed response times, as well as the need for plant identification guides that include information on how to distinguish problematic invasive plants from similar native species.

Light affects the germination and normal seedling development of Neotropical savanna grasses

2020 ◽  
pp. 1-4
Author(s):  
Claudiana M. Pereira ◽  
Rebeca N.A. Figueirôa ◽  
Hudson G.V. Fontenele ◽  
Heloisa S. Miranda
Keyword(s):  
Invasive Species ◽  
Seed Bank ◽  
Native Species ◽  
Seedling Recruitment ◽  
Soil Seed Bank ◽  
Light Availability ◽  
Native Grasses ◽  
Neotropical Savanna ◽  
Invasive Grasses ◽  
Biomass Component

Abstract The Cerrado is a Neotropical savanna where grasses are a major biomass component in the open vegetation physiognomies. Invasive grasses are widely used as pastures in the Cerrado, and their presence may displace native species. The persistence of native grasses relies also on reproduction via seeds, which is often dependent on seeds found buried in the soil seed bank. The literature about the effects of light availability on the germination of Neotropical savanna grasses is scarce, and germination may lead to abnormal seedlings that develop only the root or the shoot. Germination trials that overlook this fact may overestimate the potential for seedling recruitment. Therefore, we tested the effects of light availability on the germination of nine native and two invasive grasses, addressing the production of normal seedlings. Seeds were germinated in the complete absence or the presence of light (12 h photoperiod under white light) for 30 days. Germination was defined as the sum of normal and abnormal seedlings. Eight species were light-dependent, decreasing the production of normal seedlings in the dark. Two native and one invasive species were non-responsive to the dark treatment, showing no change in germination or production of normal seedlings. Our results suggest that seeds buried in the soil seed bank are likely to show reduced germination and develop abnormal seedlings, reinforcing a bottleneck for the recruitment of native grasses. For invasive species, however, the potential of seedling recruitment was minimally reduced by light, suggesting a competitive advantage for the recruitment of these species.

scholarly journals The effects of successional stage and size of gaps on recruitment of clonal plants in overgrowing Molinietum caeruleae meadows

2014 ◽  
Vol 67 (4) ◽  
pp. 87-98 ◽  
Author(s):  
Kinga Kostrakiewicz-Gierałt
Keyword(s):  
Seedling Recruitment ◽  
Abiotic Factors ◽  
Negative Relationship ◽  
Clonal Plants ◽  
Plant Canopy ◽  
Lateral Growth ◽  
Successional Stage ◽  
Closed Canopy ◽  
Successional Stages ◽  
Almost All

<p>In majority of plant communities with a closed canopy, the disturbances created by abiotic factors and biotic agents contribute to origin of an area free of existing vegetation and considered as safe sites for seedling recruitment. Although the gaps are characterized by several features, the size is proposed to be the most important characteristic. The investigations of recruitment of clonal taxa in different–sized gaps were conducted in the years 2011–2012 in <em>Molinietum caeruleae</em> meadows representing various successional stages and dominated by different species. Patch ES, representing early-successional stage, was dominated by small meadow species, Patch MS, representing mid-successional stage, was prevailed by tall-growing macroforbs, while Patch LS representing late-successional stage was overgrown by macroforbs and willows. In the successive sites the mean height of plant canopy, as well as the period of spring inundation increased gradually.</p><p>The total number of species and seedlings decreased from the Patch ES, through the Patch MS, to the Patch LS. Almost all plants presenting positive correlation between seedling number and gap area created hypogeogenous stems with substantial lateral growth and considerable number of short-lived daughter ramets allowing the fast colonization of neighbourhood. The majority of species showing negative relationship formed epigeogenous stems with slight lateral growth, as well as low number of long-lived ramets contributing to slow colonization of area.</p><p>In light of performed studies, it might be concluded, that making disturbance in continuous plant canopy and litter might be very effective way of conservation of <em>Molinietum caeruleae</em> meadows. The creation of different-sized gaps seems to be especially valuable due to the maintenance of heterogeneity of clonal species, which is particularly important in advanced successional stages.</p>

The Biology of Invasive Alien Plants in Canada. 4. Heracleum mantegazzianum Sommier & Levier

2006 ◽  
Vol 86 (2) ◽  
pp. 569-589 ◽  
Author(s):  
Nicholas A. Page ◽  
Ronald E. Wall ◽  
Stephen J. Darbyshire ◽  
Gerald A. Mulligan
Keyword(s):  
British Columbia ◽  
Urban Areas ◽  
Native Species ◽  
Invasive Plant ◽  
Leaf Shape ◽  
Herbarium Specimens ◽  
Natural Ecosystems ◽  
Alien Plant ◽  
Invasive Alien Plant ◽  
Heracleum Mantegazzianum

Heracleum mantegazzianum (giant hogweed) is an invasive alien plant of management concern in southern Canada where it has escaped from horticulture and established and spread in natural, ruderal, and agricultural ecosystems. It poses a threat to natural ecosystems and human health, and is also a weed in agricultural and urban areas. It is a member of the Carrot family (Apiaceae) and is closely related to the native species Heracleum maximum Bartram (cow-parsnip). It is a monocarpic perennial, which generally flowers in its 3rd or 4th year. Large size, leaf shape, dark reddish pigments in patches on stems and petioles, and fruit characteristics readily distinguish H. mantegazzianum from other plants in Canada. It is increasingly common in riparian areas, floodplains, and forest edges in or near urban areas in southwestern British Columbia and southern Ontario. Based on herbarium specimens, H. mantegazzianum was first recorded in Ontario in 1949, British Columbia in 1964, Nova Scotia in 1980, Quebec in 1990, and New Brunswick in 2000. The development of dense stands of H. mantegazzianum can also reduce the richness of native plants. Contact with H. mantegazzianum can cause phytophotodermatitis, a serious skin inflammation caused by UV photo-activation of furanocoumarins present in the sap. Control methods include herbicide application, mechanical cutting, and animal grazing, but strategies to address seed dispersal and re-establishment from dormant seed must also be adopted. Widespread establishment in southern Canada suggests that eradication is unlikely. However, range expansion and rapid population growth can be prevented through strategic management including public education. Key words: Giant hogweed, Heracleum mantegazzianum, Apiaceae, HERMZ, invasive plant, weed biology, furanocoumarins

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