scholarly journals Influence of nutrient enrichment on the growth, recruitment and trophic ecology of a highly invasive freshwater fish

2020 ◽  
Vol 54 (4) ◽  
pp. 1029-1039
Author(s):  
Ana Ruiz-Navarro ◽  
Michelle C. Jackson ◽  
David Almeida ◽  
J. Robert Britton
Keyword(s):  
Nutrient Enrichment ◽  
Trophic Ecology ◽  
Biotic Resistance ◽  
Propagule Pressure ◽  
Somatic Growth ◽  
Nutrient Status ◽  
Trophic Niche ◽  
Topmouth Gudgeon ◽  
Establishment Probability ◽  
Mature Fish

Abstract The establishment probability of introduced alien fish can be context dependent, varying according to factors including propagule pressure and biotic resistance. The influence of nutrient enrichment on establishment outcomes of alien fishes is uncertain, yet this is a common anthropogenic stressor of many freshwaters. Here, the small-bodied alien topmouth gudgeon Pseudorasbora parva was used in mesocosms to experimentally test how a gradient of nutrient enrichment affected their growth rates, recruitment and trophic ecology. A ‘Control’ represented ambient, mesotrophic conditions, while treatments covered three levels of nutrient enrichment: low (eutrophic), medium (hypertrophic) and high (very hypertrophic). Each mesocosm was seeded with 6 mature P. parva (equal sex ratio) at the start of their reproductive season. After 100 days, length increments of the adult fish were significantly elevated in the low treatment, and these fish had also produced significantly higher numbers of 0+ fish compared to all other treatments. The trophic niche width of the mature fish was substantially higher in the control than the treatments, but this did not appear to confer any advantages to them in somatic growth rate or reproductive output. These results suggest that the nutrient status of receiving waters can have substantial impacts on the outcomes of fish introductions, where eutrophic conditions can assist the rapid population establishment of some alien species.

scholarly journals Plant invasions: merging the concepts of species invasiveness and community invasibility

2006 ◽  
Vol 30 (3) ◽  
pp. 409-431 ◽  
Author(s):  
David M. Richardson ◽  
Petr Pyšek
Keyword(s):  
Biotic Resistance ◽  
Propagule Pressure ◽  
Plant Invasions ◽  
Invasion Ecology ◽  
Natural Ecosystems ◽  
Long Distance ◽  
Fluctuating Resources ◽  
Species Invasiveness ◽  
Tens Rule ◽  
New Research

This paper considers key issues in plant invasion ecology, where findings published since 1990 have significantly improved our understanding of many aspects of invasions. The review focuses on vascular plants invading natural and semi-natural ecosystems, and on fundamental ecological issues relating to species invasiveness and community invasibility. Three big questions addressed by the SCOPE programme in the 1980s (which species invade; which habitats are invaded; and how can we manage invasions?) still underpin most work in invasion ecology. Some organizing and unifying themes in the field are organism-focused and relate to species invasiveness (the tens rule; the concept of residence time; taxonomic patterns and Darwin’s naturalization hypothesis; issues of phenotypic plasticity and rapid evolutionary change, including evolution of increased competitive ability hypothesis; the role of long-distance dispersal). Others are ecosystem-centred and deal with determinants of the invasibility of communities, habitats and regions (levels of invasion, invasibility and propagule pressure; the biotic resistance hypothesis and the links between diversity and invasibility; synergisms, mutualisms, and invasional meltdown). Some theories have taken an overarching approach to plant invasions by integrating the concepts of species invasiveness and community invasibility (a theory of seed plant invasiveness; fluctuating resources theory of invasibility). Concepts, hypotheses and theories reviewed here can be linked to the naturalization-invasion continuum concept, which relates invasion processes with a sequence of environmental and biotic barriers that an introduced species must negotiate to become casual, naturalized and invasive. New research tools and improved research links between invasion ecology and succession ecology, community ecology, conservation biology and weed science, respectively, have strengthened the conceptual pillars of invasion ecology.

scholarly journals Trophic ecology of sea urchins in coral-rocky reef systems, Ecuador

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1578 ◽  
Author(s):  
Nancy Cabanillas-Terán ◽  
Peggy Loor-Andrade ◽  
Ruber Rodríguez-Barreras ◽  
Jorge Cortés
Keyword(s):  
Stable Isotope ◽  
Trophic Ecology ◽  
Habitat Degradation ◽  
Sea Urchins ◽  
Relative Proportion ◽  
Isotope Analysis ◽  
Niche Overlap ◽  
Trophic Niche ◽  
Rocky Reef ◽  
Trophic Overlap

Sea urchins are important grazers and influence reef development in the Eastern Tropical Pacific (ETP).Diadema mexicanumandEucidaris thouarsiiare the most important sea urchins on the Ecuadorian coastal reefs. This study provided a trophic scenario for these two species of echinoids in the coral-rocky reef bottoms of the Ecuadorian coast, using stable isotopes. We evaluated the relative proportion of algal resources assimilated, and trophic niche of the two sea urchins in the most southern coral-rocky reefs of the ETP in two sites with different disturbance level. Bayesian models were used to estimate the contribution of algal sources, niche breadth, and trophic overlap between the two species. The sea urchins behaved as opportunistic feeders, although they showed differential resource assimilation.Eucidaris thouarsiiis the dominant species in disturbed environments; likewise, their niche amplitude was broader than that ofD. mexicanumwhen conditions were not optimal. However, there was no niche overlap between the species. The Stable Isotope Analysis in R (SIAR) indicated that both sea urchins shared limiting resources in the disturbed area, mainlyDictyotaspp. (contributions of up to 85% forD. mexicanumand up to 75% forE. thouarsii). The Stable Isotope Bayesian Ellipses in R (SIBER) analysis results indicated less interspecific competition in the undisturbed site. Our results suggested a trophic niche partitioning between sympatric sea urchin species in coastal areas of the ETP, but the limitation of resources could lead to trophic overlap and stronger habitat degradation.

Biotic resistance to plant invasions.

2020 ◽  
pp. 177-191
Author(s):  
John D. Parker ◽  
◽  
John L. Devaney ◽  
Nathan P. Lemoine ◽  
◽  
...  
Keyword(s):  
Biotic Resistance ◽  
Propagule Pressure ◽  
Empirical Support ◽  
Plant Invasions ◽  
Plant Invaders ◽  
History Of Research ◽  
History Of ◽  
Direct And Indirect Impacts ◽  
Indirect Impacts ◽  
The Tropics

Biotic resistance to plant invasions takes many forms: consumption by native herbivores, competition with native plants and infection by native pathogens. But how often does biotic resistance prevent the damaging monocultures that typify the most problematic plant invaders, and how often is biotic resistance overwhelmed by the direct and indirect impacts of human activities? This chapter attempts to answer these questions, drawing on the long history of research into biotic resistance. We first briefly describe the major forms of biotic resistance to exotic plant invasions as an antecedent to other, more detailed chapters on competition, herbivory and pathogens. We then describe a new neutral model where variance in disturbance promotes invasions over the short term, but over longer timescales only propagule pressure drives invasions. These findings are a cautionary tale; pending increases in global trade and travel, particularly to the tropics, may provide the prerequisite disturbance and propagule pressure needed to ultimately stoke further invasions. Finally, we highlight case studies where invasions have been mitigated by restoration of biotic resistance from native herbivores and competitors. These studies provide strong empirical support that conservation of native biodiversity can be a nature-based solution to some invasions, although it remains to be seen if climate change will alter these effects over longer timescales.

Interactions between abiotic constraint, propagule pressure, and biotic resistance regulate plant invasion

Oecologia ◽  
2014 ◽  
Vol 178 (1) ◽  
pp. 285-296 ◽  
Author(s):  
Chaeho Byun ◽  
Sylvie de Blois ◽  
Jacques Brisson
Keyword(s):  
Plant Invasion ◽  
Biotic Resistance ◽  
Propagule Pressure

Identification of trophic niches of subterranean diving beetles in a calcrete aquifer by DNA and stable isotope analyses

2014 ◽  
Vol 65 (2) ◽  
pp. 95 ◽  
Author(s):  
Tessa M. Bradford ◽  
William F. Humphreys ◽  
Andrew D. Austin ◽  
Steven J. B. Cooper
Keyword(s):  
Stable Isotope ◽  
Trophic Ecology ◽  
Niche Partitioning ◽  
Niche Differentiation ◽  
Trophic Niche ◽  
Coi Gene ◽  
Stable Isotope Analyses ◽  
Prey Preferences ◽  
Diving Beetles ◽  
Isotope Analyses

The Yilgarn calcrete aquifers in Western Australia are an interesting system for investigating the process of speciation within subterranean habitats, because of the limited opportunities for dispersal between isolated calcretes. The presence of different-sized diving beetles (Dytiscidae) in separate calcretes, including sympatric sister-species pairs, suggests that species may have evolved within calcretes by an adaptive shift as a result of ecological-niche differentiation. We have studied the potential for trophic niche partitioning in a sister triplet of diving beetles, of distinctly different sizes, from a single aquifer. Fragments of the mitochondrial COI gene, specific to known species of amphipods and copepods, were polymerase chain reaction-amplified from each of the three beetle species, indicating that there is an overlap in their prey items. Significant differences were found in the detected diets of the three species, and results showed a propensity for prey preferences of amphipods by the large beetles and one species of copepod for the small beetles. A terrestrial source of carbon to the calcrete was suggested by stable isotope analyses. The combined approach of molecular, stable isotope and behavioural studies have provided insight into the trophic ecology of this difficult-to-access environment, providing a framework for more fine-scale analyses of the diet of different-sized species to examine speciation underground.

Trophic ecology of large pelagic fish in the Saint Peter and Saint Paul Archipelago, Brazil

2019 ◽  
Vol 70 (10) ◽  
pp. 1402 ◽  
Author(s):  
F. V. Albuquerque ◽  
A. F. Navia ◽  
T. Vaske ◽  
O. Crespo ◽  
F. H. V. Hazin
Keyword(s):  
Trophic Ecology ◽  
Feeding Habits ◽  
Saint Paul ◽  
Pelagic Fish ◽  
Trophic Niche ◽  
Trophic Relationships ◽  
Main Prey ◽  
Important Prey ◽  
Saint Peter ◽  
Prey Items

Trophic relationships of large pelagic predators can determine the structure and dynamics of oceanic food webs. The feeding habits and trophic ecology of five large pelagic fish (Acanthocybium solandri, Coryphaena hippurus, Elagatis bipinnulata, Thunnus albacares and Thunnus atlanticus) in the Saint Peter and Saint Paul Archipelago were evaluated to determine whether there is a trophic-niche overlap or resource partitioning among them. Eighty prey items found in 1528 stomachs were identified and grouped into Cephalopoda, Cnidaria, Crustacea, Gastropoda, Teleostei and Tunicata. Exocoetidae and Scombridae were the main prey in the diet of Acanthocybium solandri. In C. hippurus, Cheilopogon cyanopterus and Exocoetus volitans were the most important prey items, whereas C. cyanopterus was the main prey for T. albacares. Thunnus atlanticus consumed a great proportion of invertebrate species, with shrimps of Sergestidae family being particularly important. The gastropod Cavolinia sp. was the most important prey for E. bipinnulata. The five species had a high trophic specialisation and a high trophic level (>4.4), whereas most dietary overlaps were consistently low. The most important factor for diet dissimilarity was the consumption of Exocoetidade. All species were classified as top predators with varied diets, indicating their structural and functional importance in the food web of the Archipelago.

scholarly journals How fishing intensity affects the spatial and trophic ecology of two gull species breeding in sympatry

2018 ◽  
Vol 75 (6) ◽  
pp. 1949-1964 ◽  
Author(s):  
Diana M Matos ◽  
Jaime A Ramos ◽  
Joana G Calado ◽  
Filipe R Ceia ◽  
Jessica Hey ◽  
...  
Keyword(s):  
Trophic Ecology ◽  
Habitat Preferences ◽  
Isotope Analysis ◽  
Demersal Fish ◽  
Trophic Niche ◽  
Isotopic Niche ◽  
Temporal Segregation ◽  
Fishery Discards ◽  
Individual Tracking ◽  
South Portugal

Abstract Fisheries produce large quantities of discards, an important resource for scavenging seabirds. However, a policy reform banning discards, which is soon to be implemented within the EU, will impose a food shortage upon scavengers, and it is still largely unknown how scavengers will behave. We studied the diet (hard remains), trophic (stable isotope analysis), and foraging (individual tracking) ecology of two gull species breeding in sympatry: Audouin’s gull Larus audouinii (AG) and yellow-legged gull Larus michahellis (YLG), in South Portugal, under normal fishery activity (NFA; work days) and low fishery activity (LFA; weekends), over two consecutive years. We established a pattern of dietary, spatial, and temporal segregation between the two gull species. Under LFA, yellow-legged gulls reduced their time spent at-sea, thus foraging more in alternative habitats (e.g. refuse dumps) and widening their isotopic niche (i.e. generalist behaviour). Contrastingly, Audouin’s gull had a narrower trophic niche (i.e. specialist behaviour), foraging exclusively at-sea, reducing the amount of demersal fish and increasing the amount of pelagic fish in their diet. Under NFA, both species foraged mostly at-sea, feeding almost exclusively on fish, with increased consumption of demersal species (i.e. fishery discards). In general, yellow-legged gull had a broader trophic niche (i.e. generalist behaviour) when compared with the narrower isotopic niche of Audouin’s gull (i.e. specialist behaviour). Overall, both gull species relied heavily on fishery discards. However, there was visible dietary, spatial, and temporal segregation between the two species, associated with their dietary and habitat preferences that could be attributed to the availability of anthropogenic resources, such as fishery discards.

scholarly journals Long-term colonisation and propagule pressure of fish assemblages in a Neotropical floodplain

2021 ◽  
Author(s):  
Luis Artur Valões Bezerra ◽  
Simone Libralato ◽  
Jan Kubecka ◽  
Andre Padial
Keyword(s):  
Biological Invasions ◽  
Native Species ◽  
Fish Assemblages ◽  
Biotic Resistance ◽  
Propagule Pressure ◽  
Paraná River ◽  
River Floodplain ◽  
Parana River ◽  
Paraná River Floodplain

Abstract Biological invasions are a major threat to biodiversity in the Neotropical region. However, few studies have evaluated the mechanisms underlying the long-term establishment of fish propagules in aquatic environments. Here, we associated fish biomass, species richness, and proportion of non-native species (contamination index) to quantify propagule and colonisation pressures, and fish biodiversity (measured by the Kempton’s index) in lakes and rivers of the Parana River floodplain. We organised species into native and non-native assemblages sampled by gillnetting and beach seining in spatio-temporal gradients, seasonally, from 2000 to 2017. Native and non-native Kempton’s indices were inversely correlated, native extinctions occurred locally with non-native biotic differentiation in lakes, rivers, and ecosystem contamination. A constant propagule pressure resulted in an overwhelming biodiversity of non-natives at the end of the evaluated time series. Biotic resistance to introduction was not evidenced in our deterministic trends. The observed patterns agreed with previous studies highlighting native biotic homogenisation and species extinctions, depending on biological invasions, landscape connectivity, and riverine impoundments. Long-term propagule pressure and non-native fish colonisation were the drivers of biodiversity that led to the predominance of non-native over native assemblages in the Parana River floodplain.

scholarly journals Individual niche trajectories in nesting green turtles on Rocas Atoll, Brazil: an isotopic tool to assess diet shifts over time

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Karoline Fernanda Ferreira Agostinho ◽  
Leandro Rabello Monteiro ◽  
Ana Paula Madeira Di Beneditto
Keyword(s):  
Trophic Ecology ◽  
Isotope Analysis ◽  
Trophic Niche ◽  
Northeastern Brazil ◽  
Diet Shift ◽  
Isotopic Niche ◽  
Temporal Window ◽  
Temporal Dimension ◽  
Green Turtles ◽  
Diet Shifts

Abstract In this study, multi-tissue (yolk and carapace) stable isotope analysis was used to assess individual isotopic niche trajectories of nesting green turtles on Rocas Atoll, off northeastern Brazil, and to reveal a diet shift in the temporal dimension. The diet trajectories of individual green turtles were highly directional, with a stronger component towards decreasing values of δ15N from carapace to yolk. When the green turtles are in their foraging sites (temporal window measured by the yolk samples), they are more herbivores. Conversely, in a broader temporal window, the green turtles demonstrate a carnivore-omnivore strategy, such as represented by heavier δ15N values in the carapace. This finding confirms a temporal diet shift. This is the first study that applies trophic niche trajectories for sea turtles, adding a new isotopic tool to understand the trophic ecology of these migrant animals.

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