What is the impact of Impatiens glandulifera on species diversity of invaded riparian vegetation?

2006 ◽  
Vol 132 (2) ◽  
pp. 143-152 ◽  
Author(s):  
Martin Hejda ◽  
Petr Pyšek
Keyword(s):  
Species Diversity ◽  
Riparian Vegetation ◽  
Impatiens Glandulifera ◽  
The Impact

scholarly journals Bulk Drag Predictions of Riparian Arundo donax Stands through UAV-Acquired Multispectral Images

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1333
Author(s):  
Giuseppe Francesco Cesare Lama ◽  
Mariano Crimaldi ◽  
Vittorio Pasquino ◽  
Roberta Padulano ◽  
Giovanni Battista Chirico
Keyword(s):  
Riparian Vegetation ◽  
Vegetation Index ◽  
Arundo Donax ◽  
Water Bodies ◽  
Giant Reed ◽  
Multispectral Images ◽  
Drainage Channel ◽  
Area Index ◽  
Riparian Plants ◽  
The Impact

Estimating the main hydrodynamic features of real vegetated water bodies is crucial to assure a balance between their hydraulic conveyance and environmental quality. Riparian vegetation stands have a high impact on vegetated channels. The present work has the aim to integrate riparian vegetation’s reflectance indices and hydrodynamics of real vegetated water flows to assess the impact of riparian vegetation morphometry on bulk drag coefficients distribution along an abandoned vegetated drainage channel fully covered by 9–10 m high Arundo donax (commonly known as giant reed) stands, starting from flow average velocities measurements at 30 cross-sections identified along the channel. A map of riparian vegetation cover was obtained through digital processing of Unnamed Aerial Vehicle (UAV)-acquired multispectral images, which represent a fast way to observe riparian plants’ traits in hardly accessible areas such as vegetated water bodies in natural conditions. In this study, the portion of riparian plants effectively interacting with flow was expressed in terms of ground-based Leaf Area Index measurements (LAI), which easily related to UAV-based Normalized Difference Vegetation Index (NDVI). The comparative analysis between Arundo donax stands NDVI and LAI map enabled the analysis of the impact of UAV-acquired multispectral imagery on bulk drag predictions along the vegetated drainage channel.

scholarly journals Vegetation Dynamic Assessment by NDVI and Field Observations for Sustainability of China’s Wulagai River Basin

2021 ◽  
Vol 18 (5) ◽  
pp. 2528
Author(s):  
Panpan Chen ◽  
Huamin Liu ◽  
Zongming Wang ◽  
Dehua Mao ◽  
Cunzhu Liang ◽  
...  
Keyword(s):  
Species Diversity ◽  
River Basin ◽  
Vegetation Change ◽  
Vegetation Index ◽  
Dynamic Assessment ◽  
Indicator System ◽  
Vegetation Changes ◽  
Vegetation Dynamic ◽  
Management Policies ◽  
The Impact

Accurate monitoring of grassland vegetation dynamics is essential for ecosystem restoration and the implementation of integrated management policies. A lack of information on vegetation changes in the Wulagai River Basin restricts regional development. Therefore, in this study, we integrated remote sensing, meteorological, and field plant community survey data in order to characterize vegetation and ecosystem changes from 1997 to 2018. The residual trend (RESTREND) method was utilized to detect vegetation changes caused by human factors, as well as to evaluate the impact of the management of pastures. Our results reveal that the normalized difference vegetation index (NDVI) of each examined ecosystem type showed an increasing trend, in which anthropogenic impact was the primary driving force of vegetation change. Our field survey confirmed that the meadow steppe ecosystem increased in species diversity and aboveground biomass; however, the typical steppe and riparian wet meadow ecosystems experienced species diversity and biomass degradation, therefore suggesting that an increase in NDVI may not directly reflect ecosystem improvement. Selecting an optimal indicator or indicator system is necessary in order to formulate reasonable grassland management policies for increasing the sustainability of grassland ecosystems.

Controlling Purple Jewelweed (Impatiens glandulifera): Assessment of Feasibility and Costs

2017 ◽  
Vol 10 (3) ◽  
pp. 254-261
Author(s):  
Michaël Leblanc ◽  
Claude Lavoie
Keyword(s):  
Riparian Vegetation ◽  
Stem Density ◽  
Impatiens Glandulifera ◽  
Work Time ◽  
Exotic Invasive Species ◽  
Exotic Invasive ◽  
Time Required ◽  
Density And Biomass ◽  
The Relationship ◽  
Control Campaign

We experimentally tested the feasibility of a control campaign of purple jewelweed (Impatiens glandulifera), an exotic invasive species in Europe and North America. We evaluated the amount of time and money required to control the plant along riverbanks, with particular attention paid to the recovery of riparian vegetation following hand pulling and bagging. Work time was directly and significantly related to stem density and fresh biomass of the invader, but the relationship was stronger for density. Density and biomass were strongly reduced by the first hand-pulling operation from a mean of 45 to 2 stems m−2 and from a mean of 0.95 kg m−2 to nearly zero, a good performance but not enough to negate the need for a second hand pulling later in the summer. A single hand pulling significantly reduced the cover of purple jewelweed from to 30% to 7%. Riparian vegetation disturbed by the first hand pulling largely recovered during the following 30 d. Expressed over an area of 1 ha, the total amount of time required to control purple jewelweed is 1,400 work hours over 2 yr, or a minimum investment of Can$21,000 (US$17,000). Although controlling a well-established purple jewelweed population is expensive, to properly evaluate the benefits, we must also consider the costs of soil erosion caused by this species.

Unele aspecte metodologice de studiu a biodiversitatii si productivitatii fitocenozelor din cadrul ecosistemelor urbane

2019 ◽  
Author(s):  
Constantin Bulimaga ◽  
◽  
Anastasia Portarescu ◽  
Keyword(s):  
Riparian Vegetation ◽  
Anthropogenic Activities ◽  
Natural Ecosystems ◽  
Impact Action ◽  
Productive Potential ◽  
Study Methodology ◽  
Biodiversity Study ◽  
The Impact ◽  
The City ◽  
Urban Activities

Anthropogenic activities cause damage to the natural ecosystems in the city in various ways, which contributes to the reduction of biodiversity. Considering that biodiversity is becoming more vulnerable to the impact action triggered by urban activities is necessary to monitor it in order to take urgent measures to protect and preserve it. The plant biodiversity study methodology includes methods that help determine phytocenosis parameters and assess biomass in order to estimate the productive potential of phytocenosis. Carrying out the research according to the proposed methodology will make it possible to assess the anthropogenic impact on the terrestrial and riparian vegetation.

The impact of marine protected areas on temporal stability of fish species diversity

2021 ◽  
Author(s):  
Amanda K. Pettersen ◽  
Ezequiel M. Marzinelli ◽  
Peter Steinberg ◽  
Melinda A. Coleman
Keyword(s):  
Species Diversity ◽  
Protected Areas ◽  
Fish Species ◽  
Marine Protected Areas ◽  
Temporal Stability ◽  
The Impact ◽  
Fish Species Diversity

scholarly journals Is the impact of eutrophication on phytoplankton diversity dependent on lake volume/ecosystem size?

2016 ◽  
Author(s):  
Didier L. Baho ◽  
Stina Drakare ◽  
Richard K. Johnson ◽  
Craig R. Allen ◽  
David G. Angeler
Keyword(s):  
Species Diversity ◽  
Growing Season ◽  
Phytoplankton Diversity ◽  
Habitat Features ◽  
Anthropogenic Stressors ◽  
Lake Volume ◽  
Ecosystem Size ◽  
Phytoplankton Communities ◽  
The Impact ◽  
Local Habitat

<p>Research focusing on biodiversity responses to the interactions of ecosystem size and anthropogenic stressors are based mainly on correlative gradient studies, and may therefore confound size-stress relationships due to spatial context and differences in local habitat features across ecosystems. We investigated how local factors related to anthropogenic stressors (<em>e.g.,</em> eutrophication) interact with ecosystem size to influence species diversity. In this study, constructed lake mesocosms (with two contrasting volumes: 1020 (shallow mesocosms) and 2150 (deep mesocosms) litres) were used to simulate ecosystems of different size and manipulated nutrient levels to simulate mesotrophic and hypertrophic conditions. Using a factorial design, we assessed how the interaction between ecosystem size and nutrients influences phytoplankton diversity. We assessed community metrics (richness, diversity, evenness and total biovolumes) and multivariate community structure over a growing season (May to early November 2011). Different community structures were found between deep and shallow mescosoms with nutrient enrichment: Cyanobacteria dominated in the deep and Charophyta in the shallow mesocosms. In contrast, phytoplankton communities were more similar to each other in the low nutrient treatments; only Chlorophyta had generally a higher biovolume in the shallow compared to the deep mesocosms. These results suggest that ecosystem size is not only a determinant of species diversity, but that it can mediate the influence of anthropogenic effects on biodiversity. Such interactions increase the uncertainty of global change outcomes, and should therefore not be ignored in risk/impact assessment and management.</p>

Riparian Vegetation Dynamic and River Stability on Intermittent Rivers: Impact of Water Transfer Project on Tropical Drylands

2021 ◽  
Author(s):  
Camilla Santos ◽  
Leonardo Dantas Martins ◽  
Kenia Sousa da Cruz ◽  
Jonas Otaviano Praça de Souza
Keyword(s):  
Vegetation Cover ◽  
Riparian Vegetation ◽  
Google Earth ◽  
Water Transfer ◽  
Lateral Stability ◽  
Hydrological Changes ◽  
Vertical Incision ◽  
Short Period ◽  
Geomorphic Units ◽  
The Impact

&lt;p&gt;Rivers on semiarid landscapes typically are characterised by sandy geomorphic units and riverbanks, a natural factor that enhances lateral mobility. Vegetation cover is a crucial factor on lateral instability due to its impact on riverbank and geomorphic units erosion resistance. Nevertheless, riparian vegetation on intermittent and ephemeral channels show growing patterns directly affect by the flow temporality, that controls the water availability. Extended dry intervals hinder the succession ecological on geomorphic units, like bars and islands, and riverbanks and retard the growing process. This work analysed the effects of hydrological changes, caused by one water transfer project, on the bio-geomorphological patterns on riverbanks of a main intermittent river of Brazilian Drylands. Flow data series was used to understand the hydrological pattern changes; Google Earth images and UAV surveys to analyse the vegetation and riverbank behaviour from 2008 to 2020.&amp;#160; Lastly, the identification of riverbank material resistance was based on sedimentology analysis. &amp;#160;The water transfer Project PISF (Projeto de Integra&amp;#231;&amp;#227;o do S&amp;#227;o Francisco), operating since 2017 March, increase the average flow days from 137,5 to 260/300 days and decreasing the continuous dry period from 200 to 30/45 days. The impact on average annual discharge was slightest, whereas the average water transfer volume was 3m&lt;sup&gt;3&lt;/sup&gt;/s. It is essential to highlight the short period of data posterior to the water transfer and the non-regulatiry of water volume transferred; what limits the temporal representativity of the results. There were different types, and level of impacts depending on the river reach characteristics. However, in general, the longer flow permanence increases riparian vegetation density, vertical incision, and lateral stability. Riparian vegetation cover increase, from 20% to 100% on the 9 reaches analysed, across the entire channel, including bedrock reaches, with riverbanks having some rock outcrops percentage. The main changes were on sand bed reaches, that used to have, before 2017, a dynamic braiding pattern, without a clear main incised channel and thalweg shifting. Afterwards, the flow permanence, due to the water transfer project, enabled herbaceous stratus temporal continuity, contributing to surface stability and progressive bushes/trees cover growing. Lastly, the increase in lateral stability, mainly on thalweg position, facilitates the vertical incision on the sand bed reaches, representing 85% of this channel. As a secondary impact, there were necessary, to the road network, built floodway crossings at several points, which changes the channel morphology and the (dis)connectivity process. It can generate distinct channel position and morphology changes causing water and sediment retention upstream and erosion downstream. Lastly, there were slight differences in textural characteristics on riverbanks and geomorphic units, with a rise in fine sediment on the most vegetated areas/units. This analysis reveals that a fast response of riparian vegetation and sand bed reaches morphology, affecting the bio-geomorphological process and all environmental dynamic. It points to fundamental elements which need monitoring after hydrological changes, especially to intermittent and ephemeral rivers.&lt;/p&gt;

No detrimental effects of desalination waste on temperate fish assemblages

2020 ◽  
Author(s):  
Sasha K Whitmarsh ◽  
Greg M Barbara ◽  
James Brook ◽  
Dimitri Colella ◽  
Peter G Fairweather ◽  
...  
Keyword(s):  
Species Diversity ◽  
Fish Assemblages ◽  
Waste Product ◽  
Ecological Impacts ◽  
Global Changes ◽  
Reference Sites ◽  
Desalination Plant ◽  
Saline Waste ◽  
Temperate Fish ◽  
The Impact

Abstract Water resources are becoming increasingly scarce due to population growth and global changes in weather patterns. Desalination plants that extract freshwater from brackish or seawater are already being used worldwide, with many new plants being developed and built. The waste product from the extraction processes has an elevated salt concentration and can potentially cause substantial impacts to local marine flora and fauna. The present study assesses the impact of saline waste from a 100 GL/year desalination plant on southern Australian temperate fish assemblages, using baited remote underwater video. The study compared four reference sites to the impact site (desalination outfall) and found no evidence that the saline waste was having a detrimental effect on fish assemblages in proximity to the outfall, with species diversity and abundance comparable to those observed at reference sites. However, species diversity and abundance varied across geographical location, protection from fishing pressure, and reef type. Our study is one of the few assessing the ecological impacts of saline waste discharged from a large desalination plant and shows no decrease in fish diversity or abundance, which is the response typically associated with the negative impacts of anthropogenic activities on fish assemblages.

The Impact of Acanthaster on Corals and Coral Reefs in the Eastern Pacific

1974 ◽  
Vol 1 (4) ◽  
pp. 295-304 ◽  
Author(s):  
Peter W. Glynn
Keyword(s):  
Species Diversity ◽  
Field Work ◽  
Coral Community ◽  
Eastern Pacific ◽  
Live Coral ◽  
Sea Star ◽  
Coral Communities ◽  
Negative Effect ◽  
Population Sizes ◽  
The Impact

The movement of surface currents and the availability of coral prey are probably not responsible for the discontinuities in the distribution of Acanthaster (the Crown-of-thorns Starfish or Sea-star) in American waters. Temperature and salinity conditions are critical in development, and it is possible that these parameters are effective locally, for example in the Gulf of Panamá. There is a strong possibility that continuing field work will show that Acanthaster has a significantly more widespread distribution in the eastern Pacific than is currently known.Adult Acanthaster and several species of coral prey exhibited an unusually high tolerance to varying conditions of temperature and salinity. The possibility of step-wise colonization to new areas, mediated by resistant adult populations that can become established during favourable seasons, should be considered in any plans to alter the existing freshwater canal in Panamá. For introductions can be environmentally dangerous.The highest population densities of Acanthaster so far observed in the eastern Pacific, 1 individual/40 m2 to approximately 1 individual/100 m2, are comparable to population sizes in the Indo-Pacific region that are not considered to have a serious impact on coral communities. Coral destruction by Acanthaster can be significant in certain limited areas, but is usually less than that caused by other corallivores.An analysis of coral community structure in relation to Acanthaster density failed to show a significant correlation with (a) number of species, (b) number of live coral colonies, (c) species diversity (H'), or (d) species evenness (J').Prey preference data indicate that Acanthaster selectively destroys rare corals. Replacement of rare, predated corals by fast-growing species (Pocillopora spp.) has been observed in the field, showing that Acanthaster could have a negative effect on species diversity.

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