Post-invasion Period Research Articles

Effect of an invasive species Mnemiopsis leidyi on the zooplankton community structure in the Caspian Sea

Effect of an invasive species Mnemiopsis leidyi on the zooplankton community structure in the Caspian Sea

Illusion of stability: An empirical analysis of inflation data manipulation by russia after 2022

This paper explores the perceived resilience of russia’s economy under severe sanctions, investigating the potential falsification of economic data to demonstrate the growth. The hypothesis is that the relationship between the official inflation rate and the FMCG deflator index during 2019–2021 significantly differs from that of 2022–2024. Statistical methods, such as correlation analysis, Granger causality tests, and differences tests (e.g., t-tests and Wilcoxon tests), are used along with vector autoregressive (VAR) models and robust linear regressions. The study covers the pre-invasion period (2019–2021) and the post-invasion period (2022–2024), focusing on indicators like the official inflation rate, inflation expectations, CPI, and the FMCG deflator index. Findings reveal a shift from a direct to an inverse correlation between official inflation and the FMCG deflator post-2022, suggesting data manipulation. Pre-2022 models predict inflation 2-3 times higher than both post-2022 models and official statistics, raising concerns about the reliability of russia’s economic data. Further research should explore indirect metrics, such as electricity production and cargo shipments, for additional evidence of data falsification. AcknowledgmentsAlex Plastun gratefully acknowledges financial support from the New Europe College (NEC), the Center for Advanced Study, and Sumy State University.Anna Vorontsova gratefully acknowledges financial support from Sumy State University.

EU arms collaboration, procurement, and offsets: the impact of the war in Ukraine

ABSTRACT In the last twenty years, the EU has made increasingly greater efforts to boost defence cooperation among MS. To strengthen the EDTIB and avoid duplication of capabilities, the EU has encouraged “European preference” in arms procurement and MS’ defence collaborative projects, also by seeking to expunge defence offsets from the single market. Against this backdrop, on 24 February 2022, Russia invaded Ukraine. What impact has the war in Ukraine had on EU defence cooperation? Has the war impacted MS in a similar fashion or unevenly, reinforcing defence integration dynamics for some, while kickstarting disintegration for others? Two years on, a thorough analysis of the impact of the war on EU defence cooperation is still missing. This paper fills this gap by exploring three levels of analysis – arms collaboration, arms procurement, and offsets – and by comparing pre-invasion evidence with data from the post-invasion period. The analysis suggests that the Russo-Ukrainian war has negatively impacted EU defence cooperation, potentially increasing both fragmentation and non-EU dependencies. However, although MS’ threat perception and their ability to reap industrial benefits remain important to explain EU defence cooperation, integration or disintegration dynamics do not neatly map onto the geographical or size divides identified by the literature.

The disastrous consequences of Iraq’s invasion of Kuwait

This research explores the causes that led to the Iraqi invasion of Kuwait in 1990 and the severe repercussions of this action, focusing on the effects on the Iraqi economy, its political stability, and international reactions. The research aims to analyze the political and economic consequences of the postinvasion period and evaluate its long-term effects on development in Iraq. This study uses historical analysis and a qualitative approach to study the effects of the Gulf War on Iraq. The population comprises critical stakeholders involved in or affected by the Gulf War, including political leaders, government officials, international organizations, and scholars specializing in Middle Eastern politics. The sample size includes 50 individuals. Specific samples were selected to ensure a diverse representation of views on Iraq's political and economic conditions before and after the war. The data was collected based on previous research, document analysis, and interviews with former diplomats and military experts. The study relied on official documents, government reports, and UN resolutions to provide an inclusive view of the impact of the Gulf War. The results showed that the most important causes of the war were economic desperation and attempts to impose regional control and hegemony over the oil-rich Gulf region, which led to the imposition of strict financial sanctions on Iraq, which resulted in economic deterioration. This situation led to a state of political instability in Iraq. The study also pointed to international intervention in the conflict, especially by the American administration led by President Bush Sr., which reversed the course of events. The research concludes that the decision to invade had permanent and long-term economic effects as well as on Iraq's foreign relations with the international community. The significance of these findings lies in their potential to inform future policies and strategies, particularly in strengthening diplomatic efforts to address economic grievances and supporting post-conflict recovery to avoid prolonged instability, offering a hopeful outlook for the future.

Did the Indian stock market sail the Russia-Ukraine storm safely?

Did the Indian stock market sail the Russia-Ukraine storm safely?

Does Russia–Ukraine war generate herding behavior in Moscow Exchange?

PurposeThis study examines whether the Russia–Ukraine war affects herding behavior in the Moscow Exchange.Design/methodology/approachThe authors employ the daily stock closing prices of 40 firms, which constitute the MOEX Russia Index from June 16, 2021, to November 30, 2022. The period before the invasion ranges from June 16, 2021, to February 23, 2022, while the post-invasion period runs from February 24, 2022, to November 30, 2022.FindingsThe findings suggest that the Russia–Ukraine war led to the formation of herding behavior among investors in Moscow Exchange. However, this herding behavior seems to be prevalent only during market downturns.Research limitations/implicationsThe results are important for policymakers and fund managers since they help them understand behavior patterns of investors during periods of war. Given the devastating effect of herd behavior on market stability, policymakers should implement a strategy to avoid this behavior. The formation of herding behavior during the Russia–Ukraine war indicates that uncertainty and fear caused by Western sanctions lead investors to imitate others which, in turn, could lead to equity mispricing. Thus, firm managers should take into account this evidence in equity issuance decisions in order to time the market. The findings raise questions about the validity of the efficient market hypothesis during the periods of war.Originality/valueThis study represents the first attempt to explore whether the Russia–Ukraine conflict contributes to the appearance of herding behavior among investors on Moscow Exchange.

Assessing the Tax Impact of Russia’s Invasion of Ukraine: Issues Arising from an International Tax Perspective and What the Future May Hold in the Post-Invasion Period

In this article, the author addresses the main tax implications of the invasion of Ukraine and how governments have responded. It describes tax incentives of the Ukraine government, measures adopted by other European countries and EU institutions, tax issues facing Ukrainian refugees and the suspension of exchange of tax information agreements by certain European countries with Russia. Finally, some reflections are provided about possible changes in the tax landscape of Ukraine in a post-invasion era.

The Impact of the Russia-Ukraine War on the Cryptocurrency Market

This research provides the very first empirical investigation of the impact of the Russia-Ukraine war on the cryptocurrency market (Bitcoin trading volume, and returns). The findings indicate that the Russia-Ukraine war impedes Bitcoin trading volume. A 1% increase in the Russia-Ukraine war leads to a 0.2% reduction in Bitcoin trading volume. The findings also indicate that the impact is more pronounced during the post-invasion period, especially after one week of the invasion. Finally, the Russia-Ukraine war predicts Bitcoin returns in both the short and long run.

Alluvium and Empire: The Archaeology of Colonial Resettlement and Indigenous Persistence on Peru's North Coast

Alluvium and Empire: The Archaeology of Colonial Resettlement and Indigenous Persistence on Peru's North Coast

Invasive oysters as new hosts for native shell-boring polychaetes: Using historical shell collections and recent field data to investigate parasite spillback in native mussels in the Dutch Wadden Sea

Biological invasions can have manifold effects on native biota, including impacts on species interactions in invaded ecosystems. Among those are effects on parasite-host interactions, for example in cases where invaders serve as a new host for native parasites, leading to an amplification of the parasite population which may ultimately result in increased infection levels in the original native hosts (parasite spillback). In this study, we investigated the potential spillback of the native shell-boring polychaete Polydora ciliata from invasive Pacific oysters (Crassostrea (Magallana) gigas) to native mussels (Mytilus edulis) in the Dutch Wadden Sea. A field survey in the intertidal revealed that the majority of P. ciliata can nowadays be found in the shells of live but also dead Pacific oysters and much less in shells of other potential host species: mussels and periwinkles (Littorina littorea). Using a unique historical shell collection based on long-term sampling programmes in the intertidal and subtidal of the western Dutch Wadden Sea, we compared P. ciliata infections in mussels before and after the invasion of the Pacific oyster by means of x-ray scans. Both for the intertidal and subtidal, we did not detect differences in prevalence of P. ciliata in mussels between pre- and post-invasion periods. This suggests that the invasion of the Pacific oyster may not have caused a strong spillback to mussels regarding P. ciliata and thus the invasion probably had little indirect infection-mediated effects on the condition and fitness of native mussels. Instead, the acquisition of native P. ciliata by the invasive oysters suggests that they may themselves be affected by the new infections and this may warrant further research.

Using stable isotopes to analyse extinction risks and reintroduction opportunities of native species in invaded ecosystems

Invasive non-native species have pervasive impacts on native biodiversity, including population extirpations and species extinctions. Identifying reasons why a population of a native species is extirpated following an invasion often relies on literature-based results of anecdotal observations. The well-established schemes of existing risk assessments for invasive species assume that a species’ information (e.g. impacts or behavioural and biological traits) can be projected from one area to another to estimate the potential impact of a species in another environment. We used stable isotope data (δ13C, δ15N) from both invaded and uninvaded communities to predict such invasion impacts by reconstructing trophic relationships. This approach was tested on a community within a protected lake in Northern Spain where, following the introductions of non-native species, the last resident native species (the common tench Tinca tinca, the European eel Anguilla anguilla, and the whirligig beetle Gyrinus sp.) had been extirpated. Through the application of this novel approach, we found evidence that native species’ declines were related to direct predation by and resource overlap with non-native species, which occurred in conjunction with habitat modification. Using this approach, we outlined the mechanisms involved in the extirpation of native species in the post-invasion period. To compensate for losses of native species induced by invasions of non-native species, native species reintroductions might be an appropriate tool. For this, we further suggested and discussed a novel approach that predicts the outcome of arising interactions by superimposing stable isotope data from alternative sources to better estimate the success of native species´ reintroductions.

Are invasive species always negative to aquatic ecosystem services? The role of dark false mussel for water quality improvement in a multi-impacted urban coastal lagoon

Are invasive species always negative to aquatic ecosystem services? The role of dark false mussel for water quality improvement in a multi-impacted urban coastal lagoon

A Bayesian assessment of polychlorinated biphenyl contamination of fish communities in the Laurentian Great Lakes

A Bayesian assessment of polychlorinated biphenyl contamination of fish communities in the Laurentian Great Lakes

Can the invasive New Zealand mud snail (Potamopyrgus antipodarum) threaten fisheries of temperate lakes? A case study from Lake Dusia, Lithuania

Background. To date, numerous studies of the impact of snail Potamopyrgus antipodarum (Gray, 1843) on invaded ecosystems have been conducted. However, the majority of such studies intended to assess changes induced in macroinvertebrate assemblages, while the possible effects of P. antipodarum on higher trophic levels have not hitherto been studied. Of particular interest from the point of view of fisheries management is the elucidation of how this invasive snail can alter the energy flow towards higher trophic levels. When abundant, P. antipodarum consumes a substantial part of the primary production, but it is poorly consumed by native fishes. Consequently, part of its assimilated energy may become locked in lower trophic levels and fail to reach higher levels directly. Therefore, invasion of this snail may decrease fish production. Materials and methods. Several years after establishment of P. antipodarum in a temperate mesotrophic Lake Dusia, we assessed: (1) changes in the biomass of littoral macroinvertebrates (proxy to secondary production), (2) assimilation of P. antipodarum by benthivorous fish (energy flow), and (3) changes in growth and catches of littoral benthivorous fish (fish production). All the analyses were based on a merger of “grey” literature and original data during the pre- and post-invasion periods. Results. There was an evident increase in the biomass of littoral macroinvertebrates, and the assemblage changed from crustacean- to gastropod-dominated due to over-domination of P. antipodarum. However, P. antipodarum did not replace the native prey of fish. Moreover, a marked decrease was recorded in littoral fish growth and catches after the invasion of P. antipodarum. Conclusion. Dense populations of P. antipodarum may reduce the channelling of primary production towards higher trophic levels and, consequently, the invasion may threaten fisheries of temperate mesotrophic lakes.

Intensified environmental and density-dependent regulation of white perch recruitment after an ecosystem shift in the Hudson River Estuary

Long-term monitoring data were used to test whether the invasion of zebra mussels (Dreissena polymorpha) in the Hudson River Estuary in 1991 altered the influence of density dependence and environmental conditions on life-stage transitions, growth, and partial migration in white perch (Morone americana). During the post-invasion period (1992–2013), we estimated standing stocks of white perch eggs, yolk-sac larvae (YSL), post-yolk-sac larvae (PYSL), young-of-the-year (YOY), and adults as well as indices of YOY growth and spatial distribution. A series of linear and nonlinear functions were employed to model life-stage transitions, while the effects of six environmental and density-dependent variables on YOY growth and partial migration were quantified. Comparisons to pre-invasion observations (1974–1991) indicated that egg–YSL, PYSL–YOY, and YOY–yearling transitions changed significantly after the invasion, while PYSL abundance developed a stronger negative effect on YOY growth. The PYSL–YOY transition became more sensitive to density dependence and freshwater flow from 1992 to 2013, which is consistent with diminished abundance and increased environmental sensitivity of the forage base in the Hudson River Estuary reported after the zebra mussel invasion.

Collapse of the native ruffe (Gymnocephalus cernua) population in the Biesbosch lakes (the Netherlands) owing to round goby (Neogobius melanostomus) invasion

We investigated the change in benthic fish communities in three artificial lakes of the Biesbosch area in the Netherlands between two time periods: before and after the invasion of round goby (Neogobius melanostomus). Native ruffe (Gymnocephalus cernua), the dominant species in benthic gillnet and littoral beach seining catches before the invasion, almost completely disappeared in all lakes only 2 years after the invasion. We found a significant increase in 0 + perch (Perca fluviatilis) and, in some lakes, pikeperch (Sander lucioperca) abundance in gillnet catches after invasion. In the post-invasion period, the 0 + fish community was dominated by perch, and the older fish community was dominated by round goby. The species richness of 0 + fish increased in the post-invasion period owing to the invasion of gobiids. However, it did not change for older fish between periods. Our results clearly show that, owing to a similar benthic lifestyle and high niche overlap, ruffe was the only species negatively influenced by the round goby invasion. The competitive superiority of round goby over ruffe is so strong that the once-dominant species of the overall benthic fish community collapsed after only a few years of coexistence.

Effect of the invasive New Zealand mud snail (Potamopyrgus antipodarum) on the littoral macroinvertebrate community in a temperate mesotrophic lake

The chief aim of the present study was to reveal changes in a littoral macroinvertebrate community induced by the invasion of the New Zealand mud snail (Potamopyrgus antipodarum). For that purpose, we compared relevant aspects of the lake littoral macroinvertebrate community in pre- and post-invasion periods and determined the trophic position of P. antipodarum in the lake food web by performing the stable isotope-ratio analysis. The analyses performed showed that P. antipodarum is a primary consumer that may utilise a wide range of primary food sources. Overall, our study showed the following effects of the P. antipodarum invasion on the macroinvertebrate community: a definite increase in the total macroinvertebrate biomass, a significant increase in the local macroinvertebrate family richness and diversity, a shift in the community composition from crustacean- to gastropod-dominated. However, P. antipodarum invasion was not found to affect the biomass of local macroinvertebrates, which remained unchanged.

Enigmatic decline of a common fish parasite (Diplostomum spp.) in the St. Lawrence River: Evidence for a dilution effect induced by the invasive round goby.

Enigmatic decline of a common fish parasite (Diplostomum spp.) in the St. Lawrence River: Evidence for a dilution effect induced by the invasive round goby.

Simulating the Hydrologic Impact of Arundo donax Invasion on the Headwaters of the Nueces River in Texas

Arundo donax (hereafter referred to as Arundo), a robust herbaceous plant, has invaded the riparian zones of the Rio Grande River and the rivers of the Texas Hill Country over the last two decades. Arundo was first observed along the Nueces River in central Texas in 1995 by the Nueces River Authority (NRA). It then spread rapidly downstream due to its fast growth rate and availability of streamflow for its consumptive use, and it completely displaced the native vegetation, primarily Panicum virgatum (hereafter referred to as switchgrass) in the riparian zone. It was hypothesized that Arundo reduced streamflows due to higher water use by Arundo when compared to switchgrass. The overall goal of this study was to assess the impacts of Arundo invasion on hydrology of the headwaters of the Nueces River through observed long-term streamflow and precipitation data analysis and simulation modeling with the Soil and Water Assessment Tool (SWAT). The observed data analysis indicated that while there was no significant change in monthly precipitation between the pre-Arundo invasion (1979–1994) and post-Arundo invasion (1995–2010) periods, streamflows changed significantly showing a positive (slightly increasing) trend during the pre-invasion period and a negative (slightly decreasing) trend during the post-invasion periods. The simulated average (1995–2010) annual evapotranspiration of Arundo in the seven Hydrologic Response Units (HRUs) in which Arundo invaded, was higher by 137 mm when compared to switchgrass. The water uptake by Arundo was therefore higher by 7.2% over switchgrass. Higher water uptake by Arundo resulted in a 93 mm higher irrigation (water use from the reach/stream) annually when compared to switchgrass. In addition, the simulated average annual water yield (net amount of water that was generated from the seven Arundo HRUs and contributed to streamflow) under Arundo was less by about 17 mm as compared to switchgrass. In conclusion, model simulations indicated that Arundo invasion in the Nueces River has caused a statistically significant increase in water uptake and reduction in streamflow compared to the native switchgrass, which previously dominated the headwaters.

Examining shifts in zooplankton community variability following biological invasion

We examined 20 yr of zooplankton samples from Harp Lake for shifts in zooplankton variability following invasion by zooplankton predator Bythotrephes longimanus, using organism body size—as measured at high resolution by Laser Optical Plankton Counter (LOPC)—as the primary metric of investigation. A period of transitory high variability in the 2 yr post‐invasion was observed for both body size compositional variability and aggregate variability metrics, with both measures of variability shifting from low or intermediate to high variability immediately following invasion, before shifting again to intermediate variability ∼ 2 yr post‐invasion. Aggregate and compositional variability dynamics were also considered in combination over the study period, revealing that the period of transitory high variability coincided with a shift from a community‐wide stasis variability pattern to one of asynchrony, before a shift back to stasis 2 yr post‐invasion. These dynamics were related to changes in the significant zooplankton species within the Harp Lake community over the pre‐ and post‐invasion periods, and are likely to be indicative of changes in the stability in the zooplankton community following invasion by Bythotrephes. The dual consideration of aggregate and compositional variability as measured by LOPC was found to provide a valuable means to assess the ecological effects of biological invasion on zooplankton communities as a whole, extending our knowledge of the effects of invasion beyond that already revealed through more traditional taxonomic investigation.