scholarly journals Diversity and biomass of native macrophytes are negatively related to dominance of an invasive Poaceae in Brazilian sub-tropical streams

2013 ◽  
Vol 25 (2) ◽  
pp. 202-209 ◽  
Author(s):  
Luiz Felipe Gonçalves Fernandes ◽  
Mariana Carolina Teixeira ◽  
Sidinei Magela Thomaz
Keyword(s):  
Native Species ◽  
Biotic Resistance ◽  
Aquatic Macrophyte ◽  
Shannon Index ◽  
Freshwater Ecosystems ◽  
Freshwater Biodiversity ◽  
Native Communities ◽  
Environmental Perturbations ◽  
Mechanical Removal ◽  
Successful Invader

Besides exacerbated exploitation, pollution, flow alteration and habitats degradation, freshwater biodiversity is also threatened by biological invasions. This paper addresses how native aquatic macrophyte communities are affected by the non-native species Urochloa arrecta, a current successful invader in Brazilian freshwater systems. We compared the native macrophytes colonizing patches dominated and non-dominated by this invader species. We surveyed eight streams in Northwest Paraná State (Brazil). In each stream, we recorded native macrophytes' richness and biomass in sites where U. arrecta was dominant and in sites where it was not dominant or absent. No native species were found in seven, out of the eight investigated sites where U. arrecta was dominant. Thus, we found higher native species richness, Shannon index and native biomass values in sites without dominance of U. arrecta than in sites dominated by this invader. Although difficult to conclude about causes of such differences, we infer that the elevated biomass production by this grass might be the primary reason for alterations in invaded environments and for the consequent impacts on macrophytes' native communities. However, biotic resistance offered by native richer sites could be an alternative explanation for our results. To mitigate potential impacts and to prevent future environmental perturbations, we propose mechanical removal of the invasive species and maintenance or restoration of riparian vegetation, for freshwater ecosystems have vital importance for the maintenance of ecological services and biodiversity and should be preserved.

scholarly journals Pilferer, murderer of innocents or prey? The potential impact of killer shrimp (Dikerogammarus villosus) on crayfish

2020 ◽  
Vol 83 (1) ◽  
Author(s):  
Sara Roje ◽  
Kateřina Švagrová ◽  
Lukáš Veselý ◽  
Arnaud Sentis ◽  
Antonín Kouba ◽  
...  
Keyword(s):  
Native Species ◽  
Developmental Stages ◽  
Aquatic Organisms ◽  
Freshwater Ecosystems ◽  
Signal Crayfish ◽  
Dikerogammarus Villosus ◽  
Native Communities ◽  
Marbled Crayfish ◽  
Invasive Amphipod ◽  
The Impact

Abstract Freshwater ecosystems worldwide are facing the establishment of non-native species, which, in certain cases, exhibit invasive characteristics. The impacts of invaders on native communities are often detrimental, yet, the number and spread of non-native invasive species is increasing. This is resulting in novel and often unexpected combinations of non-native and native species in natural communities. While the impact of invaders on native species is increasingly well-documented, the interactions of non-native invaders with other non-native invaders are less studied. We assessed the potential of an invasive amphipod, the killer shrimp Dikerogammarus villosus (Sowinsky, 1894), to cope with other established invaders in European waters: North American crayfish of the Astacidae family—represented by signal crayfish Pacifastacus leniusculus (Dana, 1852), and the Cambaridae family—represented by marbled crayfish Procambarus virginalis Lyko, 2017. The main goal of this study was to investigate if killer shrimp, besides their role as prey of crayfish, can significantly influence their stocks by predating upon their eggs, hatchlings and free-moving early juveniles. Our results confirmed that killer shrimp can predate on crayfish eggs and hatchlings even directly from females abdomens where they are incubated and protected. As marbled crayfish have smaller and thinner egg shells as well as smaller juveniles than signal crayfish, they were more predated upon by killer shrimp than were signal crayfish. These results confirmed that the invasive killer shrimp can feed on different developmental stages of larger freshwater crustaceans and possibly other aquatic organisms.

scholarly journals The Use of Barriers to Limit the Spread of Aquatic Invasive Animal Species: A Global Review

2021 ◽  
Vol 9 ◽  
Author(s):  
Peter E. Jones ◽  
Jeroen S. Tummers ◽  
Shams M. Galib ◽  
Darragh J. Woodford ◽  
John B. Hume ◽  
...  
Keyword(s):  
Case Studies ◽  
Native Species ◽  
Management Strategy ◽  
Freshwater Ecosystems ◽  
Ecological Impacts ◽  
Management Tool ◽  
Quantitative Aspect ◽  
Freshwater Biodiversity ◽  
Diverse Range ◽  
Wide Range

Aquatic invasive species (AIS) are one of the principal threats to freshwater biodiversity. Exclusion barriers are increasingly being used as a management strategy to control the spread of AIS. However, exclusion barriers can also impact native organisms and their effectiveness is likely to be context dependent. We conducted a quantitative literature review to evaluate the use of barriers to control animal AIS in freshwater ecosystems worldwide. The quantitative aspect of the review was supplemented by case studies that describe some of the challenges, successes, and opportunities for the use of the use of AIS exclusion barriers globally. Barriers have been used since the 1950s to control the spread of AIS, but effort has been increasing since 2005 (80% of studies) and an increasingly diverse range of AIS taxa are now targeted in a wide range of habitat types. The global use of AIS barriers has been concentrated in North America (74% of studies), Australasia (11%), and Europe (10%). Physical barriers (e.g., weirs, exclusion screens, and velocity barriers) have been most widely used (47%), followed by electric (27%) and chemical barriers (12%). Fish were the most targeted taxa (86%), followed by crustaceans (10%), molluscs (3%) and amphibians (1%). Most studies have been moderately successful in limiting the passage of AIS, with 86% of the barriers tested deterring >70% of individuals. However, only 25% of studies evaluated barrier impacts on native species, and development of selective passage is still in its infancy. Most studies have been too short (47% < 1 year, 87% < 5 years) to detect ecological impacts or have failed to use robust before-after-control-impact (BACI) study designs (only 5%). Hence, more effective monitoring is required to assess the long-term effectiveness of exclusion barriers as an AIS management tool. Our global case studies highlight the pressing need for AIS control in many ecoregions, and exclusion barriers have the potential to become an effective tool in some situations. However, the design and operation of exclusion barriers must be refined to deliver selective passage of native fauna, and exclusion barriers should only be used sparingly as part of a wider integrated management strategy.

scholarly journals Reducing nutrient availability and enhancing biotic resistance limits settlement and growth of the invasive Australian swamp stonecrop (Crassula helmsii)

2020 ◽  
Vol 22 (11) ◽  
pp. 3391-3402
Author(s):  
Janneke M. M. van der Loop ◽  
Janne Tjampens ◽  
Joost J. Vogels ◽  
Hein H. van Kleef ◽  
Leon P. M. Lamers ◽  
...  
Keyword(s):  
Nutrient Availability ◽  
Native Species ◽  
Western Europe ◽  
Biotic Resistance ◽  
Habitat Type ◽  
Freshwater Ecosystems ◽  
Freshwater Wetlands ◽  
Native Plant ◽  
Alien Plant ◽  
Bare Soils

Abstract The invasive Australian swamp stonecrop, Crassula helmsii, is a perennial amphibious herb originating from Australia and New Zealand. In freshwater wetlands of North-western Europe, this alien plant species is invasive due to its efficient colonization of empty niches. The establishment of dense C. helmsii growth is threatening native biodiversity and functioning of freshwater ecosystems, especially oligotrophic wetlands with high disturbance and nutrient enrichments. As the effects of these potential drivers of ecosystem degradation are generally difficult to determine in the field, we tested the competitive strength of C. helmsii in a greenhouse experiment with two native competitor species of the same habitat type, Pilularia globulifera and Littorella uniflora. Sods dominated by either of the native species, as well as bare soils, were collected from the field and manually infested with propagules of C. helmsii. Settlement and growth of C. helmsii was assessed after five weeks. In addition, the effect of nutrient enrichment by water bird feces on competition was studied by adding waterfowl droppings. C. helmsii was able to settle successfully in all treatments, but P. globulifera and L. uniflora dominance reduced settlement success and growth of C. helmsii. On vegetated sods, the addition of waterfowl droppings had a low effect on the performance of C. helmsii, however, this treatment significantly increased biomass production on bare soils with low nutrient availability. We conclude that both absence of native competitors and eutrophication, including guanotrophication by waterfowl, explain the establishment success and invasiveness of C. helmsii. Given the fact that eradication of C. helmsii is very challenging, our results imply that management should focus on a combination of increasing local species densities and abating eutrophication. This will strongly limit the window of opportunity for invasion of C. helmsii and enhance resistance by native plant communities.

Free-living freshwater nematodes from Brazil: checklist of genera and regional patterns of diversity

Nematology ◽  
2021 ◽  
pp. 1-14
Author(s):  
Taciana Kramer de Oliveira Pinto ◽  
Sérgio A. Netto ◽  
André Morgado Esteves ◽  
Francisco José Victor de Castro ◽  
Patricia Fernandes Neres ◽  
...  
Keyword(s):  
Benthic Communities ◽  
Extreme Environments ◽  
Freshwater Ecosystems ◽  
Freshwater Biodiversity ◽  
High Turnover ◽  
Free Living ◽  
Regional Patterns ◽  
Freshwater Nematodes ◽  
Spatial Coverage ◽  
Freshwater Habitats

Summary Brazil has one of the largest varieties of aquatic ecosystems and rich freshwater biodiversity, but these components have constantly been damaged by the expansion of unsustainable activities. Free-living nematodes are an abundant and ubiquitous component of continental benthic communities, occurring in all freshwater habitats, including extreme environments. Despite this, hardly any studies have examined the generic composition of nematodes in different latitudes and the geographic overlap of assemblages. We provide data on nematode genera from six regions in Brazil, over a north-south gradient spanning about 4000 km, encompassing rivers, coastal lakes, and reservoirs with different levels of human impact. Interpolation/extrapolation curves were generated and the zeta diversity was used to assess the overlap of nematode assemblages. Freshwater nematode assemblages comprised 54 families and 132 genera. Mononchidae, Monhysteridae, Chromadoridae, Tobrilidae and Dorylaimidae were the most diverse families. Differences in diversity and high turnover of genera were found among regions, probably related to stochastic processes. Mononchus was the only widely distributed genus. Our results revealed a high biodiversity of free-living freshwater nematodes among the regions. The limited spatial coverage of the data reveals an enormous knowledge gap in a country with 12% of the world’s freshwater resources. The lack of spatial patterns, e.g., latitudinal variation, suggests that freshwater nematode assemblages are primarily structured by the intrinsic properties of habitats. This reinforces the uniqueness of freshwater ecosystems and suggests that the nematode assemblages may be sensitive to environmental disturbances, since the limited distributions of taxa may lead to lower resilience.

scholarly journals Alien Species vs. Native Species: From Community Ecology to Eco-Evolutionary Dynamics

2019 ◽  
Author(s):  
Andersonn Silveira Prestes
Keyword(s):  
Alien Species ◽  
Exotic Species ◽  
Native Species ◽  
Evolutionary Dynamics ◽  
Evolutionary Processes ◽  
Native Communities ◽  
Individualized Approach ◽  
History Of ◽  
Relationship Of ◽  
The Relationship

The establishment and spread of exotic species is a contemporary major concern. Alien species may become invasive in their new habitat, leading to both/either environmental and/or economic impacts. I briefly reviewed the literature in the last decade about the relationship of exotic species and native communities. I identified that professionals usually approach the subject in two main points of view: (1) researchers tend to point out the impacts of alien species on entire communities, evaluating if the relationship is positive, negative or neutral; (2) they focus on the eco-evolutionary processes involved in the introductions, the dynamics of invasion, and individual study cases. When evaluating the response of introductions to entire communities, evidence seems to be ambiguous and may support positive, negative or neutral relationship, especially depending on the scale approached. The unique eco-evolutionary pathways of each introduction may be a great shortcoming in the searching for generalities. On the other hand, advances have been made in understanding the dynamics of invasion on different lineages through a more selective/individualized approach. I suggest that the dynamics of invasion might be studied through a perspective in which different eco-evolutionary processes, levels of organization (from gene to entire communities), the history of the organism(s) and time are taken into account. Individual cases might be compared in attempt to understand how the relationship exotic and native works and in the search for generalities.

scholarly journals ASSESSMENT OF ECOLOGICAL STATE OF THE VELIKAYA RIVER DELTA BASED ON HYDROCHEMICAL INDICATORS AND STRUCTURE OF PHYTOPLANKTON

2017 ◽  
Vol 1 ◽  
pp. 82
Author(s):  
Tatiana Drozdenko ◽  
Sergei Mikhalap ◽  
Larisa Nikolskaya ◽  
Anna Chernova
Keyword(s):  
Water Quality ◽  
High Speed ◽  
Shannon Index ◽  
Freshwater Ecosystems ◽  
River Delta ◽  
Ecosystem Dynamics ◽  
Polluted Water ◽  
Ecological State ◽  
Sample Collection ◽  
Wide Range

The basis of the existence of freshwater ecosystems is phytoplankton, which produces most of the primary biological production, participates in repair processes and provides a wide range of ecosystem services. The short life cycle and high speed metabolism of microalgae make them ideal objects for ecological monitoring. The aim of the present study is to research the ecological state of the Velikaya river delta based on the species composition of phytoplankton community and some hydrochemical parameters. The sample collection for phytoplankton study and physicochemical measurements was carried out in summer 2016 at five stations representing different ecological locations of the Velikaya river delta. One hundred sixty five species taxa of microalgae belonging to 8 phylums were identified during the research: Bacillariophyta (37%), Chlorophyta (33.9%), Cyanophyta/Cyanobacteria (9.7%), Chrysophyta (6.1%), Euglenophyta (6.1%), Cryptophyta (3%), Dinophyta (3%), Xanthophyta (1.2%). The values of Shannon index indicate the average complexity of the microalgae communities structure. Values of Margalef index characterize the Velikaya river delta as an area of high species richness. Compared to the previous studies, a significant increase in the level of information diversity is observed, indicating an increase in the number of possible flows of substance and energy in the ecosystem. Dynamics of biogen substances in the water shows a slight increase of their concentrations. Ecological and geographical analysis proves that absolute dominance of cosmopolitan freshwater forms is typical for the algoflora of the Velikaya river delta. In relation to the pH-reaction inhabitants of neutral and slightly alkaline water dominate. Pantle–Buck saprobity index is applied for water quality assessment, which shows beta-mesosaprobic water quality in the ecosystem. Thus, the water of the Velikaya river delta could be referred to the category of moderately polluted water (class II of water quality). This is confirmed by the data of hydrochemical analysis.

Competitive naïveté between a highly successful invader and a functionally similar native species

Oecologia ◽  
2014 ◽  
Vol 175 (1) ◽  
pp. 73-84 ◽  
Author(s):  
Stephen J. Heavener ◽  
Alexandra J. R. Carthey ◽  
Peter B. Banks
Keyword(s):  
Native Species ◽  
Successful Invader

Invasive Aquatic Species

2018 ◽  
pp. 338-358 ◽  
Author(s):  
Julie A. Coetzee ◽  
Martin P. Hill ◽  
Andreas Hussner ◽  
Ana L. Nunes ◽  
Olaf L.F. Weyl
Keyword(s):  
Northern Hemisphere ◽  
Native Species ◽  
Submerged Macrophytes ◽  
Economic Impacts ◽  
Freshwater Ecosystems ◽  
Aquatic Species ◽  
Anthropogenic Influences ◽  
Freshwater Invasions ◽  
Geographical Bias ◽  
Floating Macrophytes

Freshwater ecosystems are particularly susceptible to invasions by invasive non-native species (INNS) across a range of taxa, largely as a consequence of anthropogenic influences on these systems, with a number of ecological and socio-economic impacts. This chapter reviews freshwater invasive non-native species across the globe, focusing on fishes, invertebrates, floating macrophytes, and submerged macrophytes emphasising the knowledge gaps in particular that have resulted in biases inherent in assessments of freshwater invasions. These include an ecological bias because the majority of studies focus on terrestrial invasions; a geographical bias as most studies are focused on temperate northern hemisphere systems; and a taxon bias where fish invasions, populate the literature. This chapter highlights some of the approaches needed to survey, monitor, and manage INNS.

Water Quantity and Hydrology

2018 ◽  
pp. 67-88 ◽  
Author(s):  
Matthew McCartney
Keyword(s):  
Water Discharge ◽  
Freshwater Ecosystems ◽  
Freshwater Ecosystem ◽  
Ecosystem Structure ◽  
Freshwater Biodiversity ◽  
Freshwater Habitats ◽  
And Function ◽  
Induced Changes ◽  
Ecosystem Structure And Function ◽  
Hydrological Monitoring

Freshwater ecosystems are naturally dynamic. The source of water, discharge, turnover, and residence times all affect which organisms can live in different freshwater habitats and are key determinants of freshwater ecosystem structure and function. Human-induced changes to the volume and timing of both surface and ground water flows are a leading driver of global declines in freshwater biodiversity and are likely to be exacerbated by climate change. The conservation of many wetlands around the world, including in some cases the preservation of unique flora and fauna, is now entirely dependent on continued human intervention and water management. Such management can only be successful if based on sound understanding of water budgets and hydrological processes informed by accurate hydrological monitoring. This chapter provides a brief introduction to hydrological monitoring—what needs to be measured and how—for freshwater ecology and conservation.

scholarly journals Genetic Data Suggest Multiple Introductions of the Lionfish (Pterois miles) into the Mediterranean Sea

Diversity ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 149 ◽  
Author(s):  
Andreas C. Dimitriou ◽  
Niki Chartosia ◽  
Jason M. Hall-Spencer ◽  
Periklis Kleitou ◽  
Carlos Jimenez ◽  
...  
Keyword(s):  
Red Sea ◽  
Native Species ◽  
Eastern Mediterranean ◽  
Economic Effects ◽  
Western Atlantic ◽  
Multiple Introductions ◽  
Pterois Miles ◽  
The Mediterranean ◽  
Successful Invader ◽  
Northern Red Sea

Widespread reports over the last six years confirm the establishment of lionfish (Pterois miles) populations in the eastern Mediterranean. Accumulated knowledge on lionfish invasions in the western Atlantic Ocean has shown that it is a successful invader and can have negative impacts on native species, indirect ecological repercussions and economic effects on local human societies. Here we analysed genetic sequences of lionfish from Cyprus as well as data from the whole distribution of the species, targeting the mtDNA markers cytochrome c oxidase subunit 1 (COI) and the control region (CR). Our results reflect a pattern of repeated introductions into the Mediterranean from the northern Red Sea and a secondary spread of this species west to Rhodes and Sicily. Presented results agree with previously published studies highlighting the genetic similarity with individuals from the northern Red Sea. Nevertheless, some individuals from Cyprus, in addition to those coming via the Suez Canal, were genetically similar to fish from the Indian Ocean, indicating genetic homogeneity among populations of P. miles across its current distribution, possibly facilitated by the ornamental fish trade and/or transport through ballast water.

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