scholarly journals Population dynamics and expansion of Crangonyx pseudogracilis, a potentially invasive amphipod

2021 ◽  
pp. 8
Author(s):  
Daniela Correia ◽  
Filipe Banha ◽  
Mafalda Gama ◽  
Pedro M. Anastácio
Keyword(s):  
Population Dynamics ◽  
Biodiversity Loss ◽  
Distribution Area ◽  
Amphipod Species ◽  
Exotic Invasive Species ◽  
Crangonyx Pseudogracilis ◽  
Exotic Invasive ◽  
One Year ◽  
Invasive Amphipod ◽  
Temporary River

One of the main drivers of biodiversity loss is the introduction of exotic invasive species. In 2011, an abundant population of Crangonyx pseudogracilis, a freshwater amphipod native to North America, was detected in Portugal. This study allowed us to better understand its biology, analysing the population dynamics in a temporary river and a small lake for one year, and to follow its expansion. Our results showed that this species reproduces in the temporary river during most of the year, but in the lake only from March to July. Amphipod density decreases from May to October and increases from November to April. As usual, females were larger than males, but the proportion of females was higher than males at both sampling locations. Finally, we noticed a great increase in C. pseudogracilis distribution area in relation to what was observed in 2014, with a diffusion coefficient of 2495.27 km2/year and a spread rate of 26 km/year. However, no overlap was yet detected between native and exotic amphipod species.

scholarly journals DISTRIBUTION AND POPULATION STRUCTURE OF THE INVASIVE AMPHIPOD GMELINOIDES FASCIATUS (STEBBING) IN LAKE ONEGO

2017 ◽  
Vol 1 ◽  
pp. 259
Author(s):  
Anastasiia Sidorova ◽  
Lidia Belicheva
Keyword(s):  
Alien Species ◽  
Environmental Changes ◽  
Vegetation Period ◽  
Amphipod Species ◽  
Gmelinoides Fasciatus ◽  
Artificial Ecosystems ◽  
Littoral Biotopes ◽  
One Year ◽  
Invasive Amphipod ◽  
Two Peaks

Since the middle of the ХХ century, the rapid spread of exotic species and their successful penetration in natural and artificial ecosystems has led to significant environmental changes all over the world [1, 2]. As it was pointed out by many researchers, biological invasion by alien species is one of the main threats to biodiversity [3, 4, 5, 6, 7]. Gmelinoides fasciatus (Stebbing 1899) attracts special attention due to the fact that it is the most successful alien species among other invaders in aquatic ecosystems in Eurasia. This invasive amphipod of Baikalian origin was first recorded in Lake Onego in 2001 by Berezina and Panov [8]. The results of the present study indicate that the invader significantly expanded its areal in Lake Onego during the last 15 years. At present amphipod G. fasciatus is dominant on the biomass among macrozoobenthos community in littoral biotopes of some islands and east part of the Lake. In Lake Onego the invader has a one-year life cycle with the generations of the previous and current year. Seasonal dynamics of the amphipod abundance in Lake Onego has two peaks during the vegetation period. According to our data G. fasciatus successfully reproduces in the new environment and shows stable sexual structure with sex ratio of approximately 1:1. Female fecundity of the amphipod in the Lake varied from 3 to 22 eggs per female, the average variation of fertility is 9 eggs per female. Revealed data of G. fasciatus abundance and biomass in Lake Onego are comparable with those for other water bodies where this amphipod species was successfully established earlier.

scholarly journals Impact of an Exotic Invasive Pest, Spodoptera frugiperda (Lepidoptera: Noctuidae), on Resident Communities of Pest and Natural Enemies in Maize Fields in Kenya

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1074
Author(s):  
Bonoukpoè Mawuko Sokame ◽  
Boaz Musyoka ◽  
Julius Obonyo ◽  
François Rebaudo ◽  
Elfatih M. Abdel-Rahman ◽  
...  
Keyword(s):  
Natural Enemies ◽  
Spodoptera Frugiperda ◽  
Fall Armyworm ◽  
Invasive Pest ◽  
Growth Stages ◽  
Insect Communities ◽  
Exotic Invasive Species ◽  
Before And After ◽  
Exotic Invasive ◽  
Lepidoptera Noctuidae

The interactions among insect communities influence the composition of pest complexes that attack crops and, in parallel, their natural enemies, which regulate their abundance. The lepidopteran stemborers have been the major maize pests in Kenya. Their population has been regulated by natural enemies, mostly parasitoids, some of which have been used for biological control. It is not known how a new exotic invasive species, such as the fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera, Noctuidae), may affect the abundance and parasitism of the resident stemborers. For this reason, pest and parasitism surveys have been conducted, before and after the FAW invaded Kenya, in maize fields in 40 localities across 6 agroecological zones (AEZs) during the maize-growing season, as well as at 3 different plant growth stages (pre-tasseling, reproductive, and senescence stages) in 2 elevations at mid-altitude, where all maize stemborer species used to occur together. Results indicated that the introduction of the FAW significantly correlated with the reduction of the abundance of the resident communities of maize stemborers and parasitoids in maize fields; moreover, the decrease of stemborer density after the arrival of FAW occurred mostly at both reproductive and senescent maize stages. It also suggests a possible displacement of stemborers by FAW elsewhere; for example, to other cereals. However, since this study was conducted only three years after the introduction of the FAW, further studies will need to be conducted to confirm such displacements.

Response of Deeproot Sedge (Cyperus entrerianus) to Herbicide and Prescribed Fire in Texas Coastal Prairie

2015 ◽  
Vol 8 (1) ◽  
pp. 15-31 ◽  
Author(s):  
Jonathan R. King ◽  
Andrew J. Bennett ◽  
Warren C. Conway ◽  
David J. Rosen ◽  
Brian P. Oswald
Keyword(s):  
Prescribed Fire ◽  
Treatment Options ◽  
Rapid Expansion ◽  
Coastal Prairie ◽  
Multiple Treatment ◽  
Exotic Invasive Species ◽  
Plant Groups ◽  
Exotic Invasive ◽  
Dormant Season ◽  
In Fire

AbstractIntroduced accidentally from South America, deeproot sedge is rapidly expanding in a variety of habitats throughout the southeastern United States. Of particular concern is its rapid expansion, naturalization, and formation of monocultures in Texas coastal prairie, one of the most imperiled temperate ecoregions in North America. The objective of this research was to examine how deeproot sedge responds to prescribed fire, to the herbicide imazapic, and to treatment combinations of both. Combinations of prescribed fire and imazapic treatments and imazapic-only treatments effectively reduced deeproot sedge cover and frequency. However, plots exposed to dormant season fires (with no imazapic) had greater deeproot sedge cover after burn treatments were applied, indicating that coastal prairie management using only dormant season prescribed fire will not work toward reduction or management of this exotic invasive species. Although deeproot sedge cover was often reduced in fire–imazapic treatment combinations, it was still present in treatment plots. Moreover, desirable functional plant groups (i.e., native bunchgrasses) did not respond positively to the fire–imazapic treatments, but in some instances, woody plant coverage increased. Repeated, long-term approaches using integrated and coordinated efforts with multiple treatment options will be necessary to restore community structure to desired compositional levels. Such integrated approaches should be effective in reducing deeproot sedge frequency, cover, and extent to more manageable levels throughout its introduced geographic range.

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.

Effect of Sirex noctilio (Hymenoptera: Siricidae) attack density on Pinus sylvestris (Pinaceae) survival

2019 ◽  
Vol 151 (3) ◽  
pp. 340-344
Author(s):  
Laurel J. Haavik ◽  
Brett P. Hurley ◽  
Jeremy D. Allison
Keyword(s):  
Pinus Sylvestris ◽  
Generation Time ◽  
Critical Factor ◽  
Low Density ◽  
Sirex Noctilio ◽  
Time To Death ◽  
Exotic Invasive ◽  
One Year ◽  
Wood Boring ◽  
Density Treatment

AbstractPopulation density is often a critical factor in colonisation of trees by bark and wood-boring insects and may determine whether an exotic species is likely to establish and spread. In a manipulative field study, we investigated whether density of the attacking population of an exotic invasive woodwasp, Sirex noctilio Fabricius (Hymenoptera: Siricidae), affected survival and time-to-death of a favoured host tree, Pinus sylvestris Linnaeus (Pinaceae). We introduced mating pairs of woodwasps to stressed P. sylvestris at either high (15 mating pairs, nine trees) or low (two mating pairs, nine trees) density. More trees died, and more quickly, when exposed to the high versus low density of S. noctilio (78% versus 33% of trees). In the high-density treatment, year of tree death was synonymous with production of a S. noctilio F1 cohort (one-year or two-year generation time); this pattern was not as consistent in the low-density treatment. Although sample size was limited, our results indicate that attack density affects S. noctilio colonisation of P. sylvestris.

Body growth and its implications in population dynamics of Acanthodactylus erythrurus (Schinz, 1834) in the Eastern Iberian peninsula

2019 ◽  
Vol 40 (3) ◽  
pp. 305-312
Author(s):  
Robby Marcel Drechsler ◽  
Juan Salvador Monrós
Keyword(s):  
Growth Rate ◽  
Population Dynamics ◽  
Statistical Significance ◽  
Growth Curves ◽  
High Statistical Significance ◽  
General Data ◽  
One Year ◽  
Best Fit ◽  
Logarithmic Growth

Abstract We calculated growth rate for the spiny-footed lizard (Acanthodactylus erythrurus) inhabiting coastal eastern Spain from long-term mark-recapture data. Growth curves differ between sexes, with males growing faster than females and achieving larger size maximums. In this population each sex reaches maturity at about 300 days of age, approximately 34% faster than males, and 28% faster than females studied in a population further south and west in Iberia. Our logarithmic growth model has an accuracy of 96.8% and high statistical significance ( for males and for females). Although both the exponential curve of “best fit” for growth estimated for males (), and the linear curve of “best fit” estimated for females () in a population from Cádiz (Busack and Jaksic, 1982) are also significant. The overlap between growth curves and the general data cloud of the population showed that at the end of the year the proportion of individuals younger than one year was 80% and the proportion of individuals older than one year was 20%. Our data, in agreement with calculated maximum life spans for males (1.9 years) and females (2.1 years) in Cádiz, suggest a life span of approximately two years for both sexes. Females seem to reproduce only in a unique season in their lives, at this locality, as in Cádiz (Busack and Klosterman, 1987) they likely lay only one clutch, whereas females in Morocco (Bons, 1962) may produce two.

Novel introductions and epidemic dynamics of the sudden oak death pathogen Phytophthora ramorum in Oregon forests

2020 ◽  
Author(s):  
Nicholas C Carleson ◽  
Hazel Daniels ◽  
Paul Reeser ◽  
Alan Kanaskie ◽  
Sarah Navarro ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
Population Dynamics ◽  
Microsatellite Loci ◽  
Forest Ecosystems ◽  
Principal Component ◽  
Phytophthora Ramorum ◽  
Sudden Oak Death ◽  
Clonal Lineage ◽  
Epidemic Dynamics ◽  
One Year

Sudden oak death caused by Phytophthora ramorum has been actively managed in Oregon since the early 2000’s. To date, this epidemic has been driven mostly by the NA1 clonal lineage of P. ramorum, but an outbreak of the EU1 lineage has recently emerged. Here we contrast the population dynamics of the NA1 outbreak first reported in 2001 to the outbreak of the EU1 lineage first detected in 2015. We tested if any of the lineages were introduced more than once. Infested regions of the forest were sampled between 2013-2018 (n = 903) and strains were genotyped at 15 microsatellite loci. Most genotypes observed were transient, with 272 of 358 unique genotypes emerging one year and disappearing the next. Diversity of EU1 was very low and isolates were spatially clustered (< 8 km apart), suggesting a single EU1 introduction. Some forest isolates are genetically similar to isolates collected from a local nursery in 2012, suggesting introduction of EU1 from this nursery or simultaneous introduction to both the nursery and latently into the forest. In contrast, the older NA1 populations were more polymorphic and spread over 30 km2. Principal component analysis supported two to four independent NA1 introductions. The NA1 and EU1 epidemics infest the same area but show disparate demographics owing to initial introductions of the lineages spaced 10 years apart. Comparing these epidemics provides novel insights into patterns of emergence of clonal pathogens in forest ecosystems.

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