Displacement Of Native Species Research Articles

Dietary habits change of Lessepsian migrants’ fish from the Red Sea to the Eastern Mediterranean Sea

As impacts on the Mediterranean Sea are expected to grow in the future, especially with climate change, habitat degradation, and displacement of native species by non-indigenous species (NIS), the investigation of significant alterations to trophic levels in this diverse marine habitat is important. Analysis of stable isotopes from targeted consumers has previously been shown to reliably reflect that of primary producers, thus enabling us to describe and highlight potential shifts in the food web of a particular ecosystem. In this study, we used δ13C values of essential amino acids (AA) in order to examine the dietary composition of established non-native, Lessepsian fish migrants in the Eastern Mediterranean Sea compared to that of the same fish species from their original population in the Gulf of Aqaba, Red Sea. Our data show that a clear variance in carbon isotopic signatures exists in food sources consumed by the same species between the different environments, with the exception of the classic herbivore, Siganus rivulatus (Forsskål & Niebuhr, 1775), whose very similar isotopic patterns reflect the algal source they predominantly consume in both locations. With the results of this research, we propose that Lessepsian fishes with the ability to maintain their nutritional patterns, though not necessarily that of their original food source, will acclimatize better in their new habitat. Consequences of flourishing Lessepsian fish populations include a further tropicalization of the Eastern Mediterranean Sea and the likely restructuring of local food webs.

Impact of Spartina alterniflora Invasion in Coastal Wetlands of China: Boon or Bane?

Invasive plants, like Spartina alterniflora (SA), have a competitive advantage over native flora due to their rapid utilization of vital soil nutrients. This results in the depletion of resources for native plant species, significantly impacting ecosystem diversity and stability. This comprehensive review addresses several key aspects related to SA's spread and spatial distribution in China's wetlands. The rapid expansion of Spartina alterniflora is attributed to its high reproductive ability, adaptability to environmental factors like elevated salinity, and ability to disperse its seeds via tides. Spartina alterniflora mainly were found in Zhejiang, Jiangsu, Fujian, and Shanghai provinces, accounting for more than 90% of China's total Spartina alterniflora area. Spartina alterniflora rapid growth results in displacement of native species and loss of vital microbial, plant, and animal diversity. Some studies reported that Spartina alterniflora increases carbon storage, while others argue that it weakens this function. The impact of Spartina alterniflora on organic and inorganic carbon requires further research for better understanding dynamics of carbon in coastal wetlands. The controlled growth of Spartina alterniflora can be beneficial in many aspects of the coastal wetlands' ecosystem. In China, various methods have been employed to control the invasion of SA. Physical control, such as removing the plants and converting them into fertilizer or bioenergy, has been commonly used but has limitations like air pollution and the potential for re-invasion. Chemical herbicides like Imazapyr and Haloxyfop-R-methyl have effectively controlled and prevented re-invasion in specific areas, but their potential adverse impacts are still uncertain. Wetland Park construction, aquaculture development, and substituting native or exotic species with mangroves or reed communities have also been successful. It becomes evident that a long-standing and Contextual approach is necessary to effectively manage the advantages and curtail the drawbacks associated with S. alterniflora across China.

Designing a surveillance program for early detection of alien plants and insects in Norway

Naturalized species of alien plants and animals comprise < 3% of biodiversity recorded in Norway but have had major impacts on natural ecosystems through displacement of native species. Encroachment of alien species has been especially problematic for coastal sites close to transport facilities and urban areas with high density housing. The goal of our field project was to design and test a surveillance program for early detection of alien species of vascular plants and terrestrial insects at the first phase of establishment in natural areas. In our 3-year project (2018–2020), we sampled 60 study plots in three counties in the Oslofjord region of southern Norway. Study plots (6.25 ha) were selected by two criteria: manual selection based on expert opinion (27 plots) or by random selection based on weights from a hotspot analysis of occurrence of alien species (33 plots). Vascular plants were surveyed by two experienced botanists who found a total of 239 alien species of vascular plants in 95 rounds of surveys. Insects and other invertebrates were captured with a single Malaise trap per site, with 3–4 rounds of repeated sampling. We used DNA-metabarcoding to identify invertebrates based on DNA extractions from crushed insects or from the preservative media. Over 3500 invertebrate taxa were detected in 255 rounds of sampling. We recorded 20 alien species of known risk, and 115 species that were new to Norway, including several ‘doorknocker’ species identified by previous risk assessments. We modeled the probabilities of occupancy (ψ) and detection (p) with occupancy models with repeated visits by multiple observers (vascular plants) or multiple rounds of sampling (insects). The two probabilities covaried with risk category for alien organisms and both were low for species categorized as no known or low risk (range = 0.052–0.326) but were higher for species categorized as severe risk (range = 0.318–0.651). Selecting sites at random or manually did not improve the probability of finding novel alien species, but occupancy had a weak positive relationship with housing density for some categories of alien plants and insects. We used our empirical estimates to test alternative sampling designs that would minimize the combined variance of occupancy and detection (A-optimality criterion). Sampling designs with 8–10 visits per site were best for surveillance of new alien species if the probabilities of occupancy and detection were both low, and provided low conditional probabilities of site occupancy (hat{psi }_{condl} ≤ 0.032) and a high probabilities of cumulative detection (hat{p}* ≥ 0.943). Our field results demonstrate that early detection is feasible as a key component of a national surveillance program based on early detection and rapid response.

Short Communication: Invasive mollusks Melanoides tuberculata, and Achatina fulica in Southeast Sulawesi, Indonesia

Abstract. Purnama MF, Salwiyah. 2022. Short Communication: Invasive mollusks Melanoides tuberculata, and Achatina fulica in Southeast Sulawesi, Indonesia. Biodiversitas 23: 4770-4774. Southeast Sulawesi Province has natural/artificial inland waters for various usages. For example, freshwater has supported various activities such as agriculture, plantations, inland fisheries, and ecotourism. This study reports the presence of invasive mollusk in freshwater (Melanoides tuberculata) and terrestrial (Achatina fulica) habitats. This study is the first report regarding the spatial distribution of the three invasive mollusk species in the inland waters of Southeast Sulawesi, Indonesia. All administrative areas (17 districts/cities) in Southeast Sulawesi province were invaded by A. fulica and 16 districts/cities by M. tuberculata. These invasive mollusks species are a severe threat to the preservation of native species and human health because they are an intermediate host for several types of parasites, such as the trematode group. The spreading and rapid development of these invasive mollusks is caused by their reproductive ability and resistance to poor environmental quality and airborne dispersal factors by birds, water flow, and commercial activities. This invasive species can directly cause huge economic losses as they become a pest in agricultural activities, plantations, and freshwater fisheries (aquaculture). They also can transmit pathogens and displacement of native species. Therefore, it is recommended to have a preventive effort to tackle the expansion of IAS in Southeast Sulawesi.

Geographical distribution and spatio-temporal changes in the occurrence of invasive plant species in Slovak Republic

Biological systems are subject to a dramatic increase in invading species in the 21st century due to increasing globalization around the world. In the near future, these species will cause more extensive ecological as well as socio-economic damage. Biotic invasions will result not only in a reduction of the original biodiversity, but also total loss, particularly degradation of natural habitats – especially Natura 2000 habitats. This study aims to understand the processes of spread of invasive plant species, their way of life, adaptation to environmental changes and displacement of native species. Without the local level, it is not possible to understand these processes on the regional and continental dimensions and thus implement scientific facts and findings into the prediction of the development of global biosystems. The research was conducted during the vegetation period in the years 2017–2021 in the studied areas of non-forest and forest habitats in the central part of Slovakia. We recorded 242 localities in the area with the occurrence of invasive plant species in an area of 3.057 km2 out of the total mapped area of 169.024 km2. We recorded the highest number of localities and the most expansive distribution for the species Stenactis annua, Robinia pseudoacacia, Solidago canadensis, Impatiens glandulifera and Fallopia japonica.

Study Invasive Mollusks Melanoides tuberculata and Achatina fulica in District Labuhan Batu Selatan

District Labuhanbatu selatan has natural/artificial inland waters for various usages. For example, freshwater has supported various activities such as agriculture, plantations, inland fisheries, and ecotourism. This study reports the presence of invasive mollusk in freshwater (Melanoides tuberculata) and terrestrial (Achatina fulica) habitats. This study is the first report regarding the spatial distribution of the three invasive mollusk species in the inland waters of District Labuhanbatu selatan. These invasive mollusks species are a severe threat to the preservation of native species and human health because they are an intermediate host for several types of parasites, such as the trematode group. The spreading and rapid development of these invasive mollusks is caused by their reproductive ability and resistance to poor environmental quality and airborne dispersal factors by birds, water flow, and commercial activities. This invasive species can directly cause huge economic losses as they become a pest inagricultural activities, plantations, and freshwater fisheries (aquaculture). They also can transmit pathogens and displacement of native species. Therefore, it is recommended to have a preventive effort to tackle the expansion of in District Labuhanbatu selatan.

Distribution of two European elaterids, Agriotes obscurus and A. lineatus in British Columbia: New records, and potential implications of their dispersal

• Two invasive click beetle pest species have established in southwestern British Columbia. • Surveys conducted in 2017–2019 reveal both species have now dispersed widely. • Crop damage, displacement of native species, and continued spread is expected. • Several native, non-pest species are attracted to the pheromone of these pests. Two European click beetle species, Agriotes obscurus L. (AO) and A. lineatus L. (AL) have become serious pests of agriculture in the Fraser Valley and Vancouver Island areas of British Columbia (BC), but prior to the start of this survey (2017) it was unknown if they had established elsewhere in the Province. Pitfall traps baited with sex pheromone of AO and AL were placed throughout BC in 2017–2019 and collected a total of 4,988 AO and 20,103 AL beetles in 150 trap pairs. Both species were found to be distributed throughout southern BC, including high numbers in Creston, Kelowna, Pemberton, and Salmon Arm. Traps placed in northern BC, northern Alberta, northern Idaho, or the Willamette valley in western Oregon did not collect AO or AL. Traps were also deployed for A. sputator L., a related European species that has become a serious pest of potato in eastern Canada, but this species was not collected. AO and AL traps placed in the Pemberton valley of BC also collected 474 A. ferrugineipennis (LeConte), and traps placed in the northern Okanagan valley collected 75 A. oregonensis Becker. Both are native Agriotes species not closely related to AO or AL; this is the first time A. oregonensis was collected in Canada. We discuss the potential implications of the spread of AO and AL to other agricultural areas in BC and beyond.

A SYSTEMATIC REVIEW OF LITERATURE ON INVASIVE ALIEN SPECIES IN MEXICO

Invasive alien species (IAS) have been favored by rampant deforestation and degradation of natural habitats. The wide spreading of IAS worldwide has raised international concerns given their negative impact on ecosystems, native species displacement and local population extirpations resulting in loss of biodiversity. IAS have also become a social and economic problem for local and regional public sectors. Therefore, it is urgent to establish policies to help mitigate their negative impact. Here we conducted a systematic review of research on IAS to build a database platform and analyze their current knowledge in Mexico. We compiled the information available from widespread scientific internet search tools over the last 55 years into a database, using keywords related to IAS. It was found that the predominant type of reports were articles on faunistic groups published in peer-reviewed journals. The remaining reports were related to economic costs, social perception, and the legal framework. This is a first step to identify immediate actions, and establish research priorities and management programs nationwide.

DYNAMICS OF COENOPOPULATIONS AND DISTRIBUTION ASCLEPIAS SYRIACA L. IN VARIOUS HABITATS OF AGRICULTURAL LANDSCAPES AND ADJACENT LANDS IN CENTRAL RUSSIA

Asclepias syriaca L. is species-introduced with high potential as a source of biofuel, an important fodder crop for beekeeping, a possible source of biologically active substances. However, the species has a high invasive activity and may pose a threat to the biodiversity of natural plant communities. And also pose an economic threat to agroecosystems as a segetal species. In agricultural landscapes of central Russia in various habitats the dynamics and state of coenopopulation of the introduced in the crop species A. syriaca, which has a high potential invasive hazard at this moment, was studied. Research was conducted in 2012, 2018 and 2019 in the Belgorod region near the village Kulma, Novooskolskiy urban district. To assess the dynamics of the distribution A. syriaca in 2012 a polygon was formed for stationary observations on an area of about 5000 ha called Stationary “Kulma”. Modular coenopopulations growing in various habitats were identified within this stationary. In the process of research in the conditions of agrophytocenoses and adjacent lands of the South of the Central Russian upland there is a tendency to increase the area of populations of the introduced but invasive species of A syriaca in a wide range of habitats. The fact of species-introduced A syriaca into zonal types of steppe vegetation with a tendency to increase its share in phytocenoses with possible further displacement of native species by it is established. In the conditions of habitats adjacent to agrophytocenoses, A. syriaca forms stable full-fledged populations with high seed productivity and high aboveground phytomass, which are most productive in the ecotone conditions of bayrach forests, forest belts and fallow lands. The species has a high ability to introduce agrophytocenoses to cultivated land, this makes it an extremely dangerous component of segetal communities in the Central Chernozem region, capable of causing significant economic damage. It is necessary to monitor population A syriaca in all regions and develop measures to prevent its widespread distribution in agrophytocenoses.

Expansión de Ludwigia helminthorrhiza (Onagraceae) en Cuba

The introduction of Ludwigia helminthorrhiza (Mart.) H.Hara (Onagraceae) into Cuba, by an unknown route, as well as its successful naturalization and sustained increase in its area of occupation for over 40 years is here confirmed. The importance of the quantity and quality of its diasporas for dispersal and establishment in new territories is discussed, as well as the effectiveness of the dispersal agents. The negative impacts (difficulties in the management of aquariums, sedimentation, blocking of light entry, reduction of oxygen exchange, and displacement of native species) and the positive impacts (food for fauna and bacteria housing that reduce pollution) of the introduction of this species were identified. An alert is issued regarding the possible expansion of this species to new freshwater reservoirs in the country.

Getting ahead: exploitative competition by an invasive lizard

Biological invasions are a contemporary global threat because invasive species can have substantial negative economic and ecological impacts. Invasive species can outcompete native species through two main mechanisms: interference competition (direct, negative interactions like aggression) and/or exploitative competition (indirect, negative interactions resulting from species using the same, limited resources like food). The invasive Italian wall lizard (Podarcis siculus) was introduced into Lisbon, Portugal, 20 years ago, and is believed to be locally displacing the native green Iberian wall lizard (Podarcis virescens). We experimentally tested for competition between these two lizard species by establishing heterospecific (one pair of each species) and conspecific (two pairs of the same species; control) treatments in enclosures containing a high- and a low-quality refuge. Lizards were fed from food dishes every other day. We tested if species showed interference (aggressive behaviour, stealing food and shelter exclusion) or exploitative competition (tolerance between species but differences in food consumption efficiency). We found evidence for exploitative competition: the invasive species arrived first at food stations, consumed more food and gained more weight than the native species. We suggest that exploitative competition may, in part, explain the observed displacement of P. virescens from contact areas with the invasive P. siculus. Deciphering the competitive mechanisms between invasive and native species is vital for understanding the invasion process. To become successful invaders, alien species must often outcompete native species they encounter in a new location. But how can an alien species outcompete a resident with a long evolutionary history in an environment in which the resident is expected to be better adapted? We studied an invasive and native congeneric pair of sympatric lizards to understand how they interact and potentially compete in a controlled environment. The invasive Italian wall lizard and a native congener were very tolerant of each other; however, the invasive species was first to arrive at food, ate more and grew faster, suggesting exploitative competition. This contrasts with previous studies in other introduced locations where the Italian wall lizard was more aggressive towards native lizards, suggestive of interference competition. Our results help explain why the Italian wall lizard is so successful and suggests it may compete in different ways, possibly in response to local environmental conditions and which species it may be competing with, but with the same outcome: the displacement of native species.

Contrasting Patterns of Pomacea maculata Establishment and Dispersal in an Everglades Wetland Unit and a Central Florida Lake

The spread of non-native species raises concerns about native species displacement, while other negative effects on native species (e.g., habitat degradation) should also be considered. The highly invasive non-native apple snail Pomacea maculata has raised such concerns as it has become established in a wide range of aquatic systems worldwide. While monitoring native Florida P. paludosa populations in Lake Tohopekaliga (LTOHO) from 2001 to 2009 and in Water Conservation Area 3A (WCA3A, Everglades) from 2006 to 2015, we opportunistically documented the establishment and distribution of P. maculata. We estimated snail densities and recorded egg cluster presence in three study sites (12 total plots, LTOHO) and 137 sites (WCA3). On LTOHO, native snails were absent or at very low densities prior to finding P. maculata. Few snails of either species were found in high-stem-density vegetation of the littoral zone. Pomacea maculata immigration into the littoral zone occurred following managed vegetation removal, and Hydrilla verticillata proliferation in LTOHO likely contributed to the spread of P. maculata. We found both native and non-native apple snail species in many WCA3A sites following P. maculata invasion. We initially found the non-native snail in two sites in southern WCA3A; they were mostly restricted to within three kilometers of initial sites over the next four years. Overall plant community compositions in LTOHO and WCA3A appeared less impacted than expected based on previous reports of P. maculata invasions.

Environmental filtering of native and non-native stream macrophyte assemblages by habitat disturbances in an agricultural landscape

Understanding how inter-specific variation in functional traits affects native and non-native species responses to stream disturbances, is necessary to inform management strategies, providing tools for biomonitoring, conservation and restoration. This study used a functional trait approach to characterise the responses of macrophyte assemblages to reach-scale disturbances (measured by lack of riparian shading, altered hydromorphology and eutrophication), from 97 wadeable stream sites in an agriculturally impacted region of New Zealand. To determine whether macrophyte assemblages differed due to disturbances, we examined multidimensional assemblage functional structure in relation to eleven functional traits and further related two functional diversity indices (entropy and originality) to disturbances.Macrophyte assemblages showed distinct patterns in response to disturbances, with riparian shading and hydromorphological conditions being the strongest variables shaping macrophyte functional structure. In the multidimensional space, most of the non-native species were associated with disturbed conditions. These species had traits allowing faster colonisation rates (higher number of reproductive organs and larger root-rhizome system) and superior competitive abilities for resources (tall and dense canopy, heterophylly and greater preferences for light and nitrogen). In addition, lack of riparian shading increased the abundance of functionally distinct species (i.e. entropy), and eutrophication resulted in the growth of functionally unique species (i.e. originality).We demonstrated that stream reach-scale habitat disturbances were associated to a dominance of more productive species, equating to a greater abundance of non-native species. This, can result in a displacement of native species, habitat alterations, and changes to higher trophic level assemblages. Our results suggests that reach-scale management efforts such as the conservation and restoration of riparian vegetation that provides substantial shading and hydromorphologically diverse in-stream habitat, would have beneficial direct and indirect effects on ecosystem functioning, and contribute to the mitigation of land-use impacts.

Differential effects of biological invasions on coastal blue carbon: A global review and meta‐analysis

Human-caused shifts in carbon (C) cycling and biotic exchange are defining characteristics of the Anthropocene. In marine systems, saltmarsh, seagrass, and mangrove habitats-collectively known as "blue carbon" and coastal vegetated habitats (CVHs)-are a leading sequester of global C and increasingly impacted by exotic species invasions. There is growing interest in the effect of invasion by a diverse pool of exotic species on C storage and the implications for ecosystem-based management of these systems. In a global meta-analysis, we synthesized data from 104 papers that provided 345 comparisons of habitat-level response (plant and soil C storage) from paired invaded and uninvaded sites. We found an overall net effect of significantly higher C pools in invaded CVHs amounting to 40% (±16%) higher C storage than uninvaded habitat, but effects differed among types of invaders. Elevated C storage was driven by blue C-forming plant invaders (saltmarsh grasses, seagrasses, and mangrove trees) that intensify biomass per unit area, extend and elevate coastal wetlands, and convert coastal mudflats into C-rich vegetated habitat. Introduced animal and structurally distinct primary producers had significant negative effects on C pools, driven by herbivory, trampling, and native species displacement. The role of invasion manifested differently among habitat types, with significant C storage increases in saltmarshes, decreases in seagrass, and no significant effect in mangroves. There were also counter-directional effects by the same species in different systems or locations, which underscores the importance of combining data mining with analyses of mean effect sizes in meta-analyses. Our study provides a quantitative basis for understanding differential effects of invasion on blue C habitats and will inform conservation strategies that need to balance management decisions involving invasion, C storage, and a range of other marine biodiversity and habitat functions in these coastal systems.

Non-indigenous species (NIS) of polychaetes (Annelida: Polychaeta) from the Atlantic and Mediterranean coasts of the Iberian Peninsula: an annotated checklist

This study provides an updated catalogue of non-indigenous species (NIS) of polychaetes reported from the continental coasts of the Iberian Peninsula based on the available literature. A list of 23 introduced species were regarded as established and other 11 were reported as casual, with 11 established and nine casual NIS in the Atlantic coast of the studied area and 14 established species and seven casual ones in the Mediterranean side. The most frequent way of transport was shipping (ballast water or hull fouling), which according to literature likely accounted for the introductions of 14 established species and for the presence of another casual one. To a much lesser extent aquaculture (three established and two casual species) and bait importation (one established species) were also recorded, but for a large number of species the translocation pathway was unknown. About 25% of the reported NIS originated in the Warm Western Atlantic region, followed by the Tropical Indo West-Pacific region (18%) and the Warm Eastern Atlantic (12%). In the Mediterranean coast of the Iberian Peninsula, nearly all the reported NIS originated from warm or tropical regions, but less than half of the species recorded from the Atlantic side were native of these areas. The effects of these introductions in native marine fauna are largely unknown, except for one species (Ficopomatus enigmaticus) which was reported to cause serious environmental impacts. In other cases, the displacement of native species or economic damages are suspected.

The dynamics of clonal dispersal and regenerative activity of Veronica filiformis J.E. Smith

The absence of capacity for sexual reproduction does not hinder the rapid expansion of the invasive range of the alien species Veronica filiformis J.E. Smith (Plantaginaceae). Lawn mowing or raking causes the fragmentation of shoots and accelerates vegetative reproduction of V. filiformis. The clone diameter of this species was shown to increase up to 25 times during the growing season, whereas the number of internodes increased by a factor of 1000–2000. Slender speedwell expanded from the site of initial introduction (Moscow, Russia) at the speed of 4 km/year in the northern direction and at a speed of 10 km/year in the southern direction. Illumination of the site had a more pronounced effect on the regenerative capacity of the species than the age of root-forming shoots. Invasion of meadow and forest fringe communities by this species was registered in recent decades. The high speed of expansion of the secondary distribution range, the displacement of native species, and the direct damage to lawns caused by this plant allow for the assignment of an invasive species status to V. filiformis and justify the control over the dispersal of this species.

Disturbance History, Management, and Seeding Year Precipitation Influences Vegetation Characteristics of Crested Wheatgrass Stands

Crested wheatgrass (Agropyron cristatum [L] Gaertm. and Agropyron desertorum [Fisch.] Schult.) has been seeded across millions of hectares of the sagebrush steppe and is often associated with native species displacement and low biological diversity. However, native vegetation composition of these seedings can be variable. To gain better understanding of the correlation between vegetation characteristics of crested wheatgrass seedings and their seeding history and management, we evaluated 121 crested wheatgrass seedings across a 54 230-km2 area in southeastern Oregon. Higher precipitation in the year following seeding of crested wheatgrass has long-term, negative effects on Wyoming big sagebrush (Artemisia tridentata Nutt. subsp. wyomingensis Beetle & Young) cover and density. Wyoming big sagebrush cover and density were positively correlated with age of seeding and time since fire. We also found that preseeding disturbance (burned, scarified, plowed, or herbicide) appears to have legacy effects on plant community characteristics. For example, herbicide-treated sites had significantly fewer shrubs than sites that were burned or scarified preseeding. Native vegetation cover and density were greater in grazed compared with ungrazed crested wheatgrass stands. The results of this study suggest a number of factors influence native vegetation cover and density within stands of seeded crested wheatgrass. Though disturbance history and precipitation following seeding can’t be modified, management actions may affect the cover and abundance of native vegetation in crested wheatgrass stands. Notably, grazing may reduce monoculture characteristics of crested wheatgrass stands and fire exclusion may promote sagebrush and perennial forbs.

Thermal ecological physiology of native and invasive frog species: do invaders perform better?

Biological invasions are recognized as an important biotic component of global change that threatens the composition, structure and functioning of ecosystems, resulting in loss of biodiversity and displacement of native species. Although ecological characteristics facilitating the establishment and spread of non-native species are widely recognized, little is known about organismal attributes underlying invasion success. In this study, we tested the effect of thermal acclimation on thermal tolerance and locomotor performance in the invasive Xenopus laevis and the Chilean native Calyptocephalella gayi. In particular, the maximal righting performance (μMAX), optimal temperature (TO), lower (CTmin) and upper critical thermal limits (CTmax), thermal breadth (Tbr) and the area under the performance curve (AUC) were studied after 6weeks acclimation to 10 and 20°C. We observed higher values of μmax and AUC in X. laevis in comparison to C. gayi. On the contrary, the invasive species showed lower values of CTmin in comparison to the native one. In contrast, CTmax, TO and Tbr showed no inter-specific differences. Moreover, we found that both species have the ability to acclimate their locomotor performance and lower thermal tolerance limit at low temperatures. Our results demonstrate that X. laevis is a better performer than C. gayi. Although there were differences in CTmin, the invasive and native frogs did not differ in their thermal tolerance. Interestingly, in both species the lower and upper critical thermal limits are beyond the minimal and maximal temperatures encountered in nature during the coldest and hottest month, respectively. Overall, our findings suggest that both X. laevis and C. gayi would be resilient to climate warming expectations in Chile.

Non-target effects of insect biocontrol agents and trends in host specificity since 1985.

Abstract Non-target impacts of parasitoids and predaceous arthropods used for classical biological control of invasive insects include five types of impact: (1) direct attacks on native insects; (2) negative foodweb effects, such as competition for prey, apparent competition, or displacement of native species; (3) positive foodweb effects that benefited non-target species; (4) hybridization of native species with introduced natural enemies; and (5) attacks on introduced weed biocontrol agents. Examples are presented and the commonness of effects discussed. For the most recent three decades (1985-2015), analysis of literature on the host range information for 158 species of parasitoids introduced in this period showed a shift in the third decade (2005-2015) towards a preponderance of agents with an index of genus-level (60%) or species-level (8%) specificity (with only 12% being assigned a family-level or above index of specificity) compared with the first and second decades, when 50 and 40% of introductions had family level or above categorizations of specificity and only 21-27 (1985-1994 and 1995-2004, respectively) with genus or 1-11% (1985-1994 and 1995-2004, respectively) with species-level specificity. In all three decades, 11-12% of introductions could not be classified in this manner due to lack of information. Recommendations for future actions to improve this record are made: (1) distinguish host use from population-level impact; (2) develop country-level online summaries of relevant information; (3) plan biological control projects with conservation partners; and (4) conduct post-release comparisons of actual impact to predicted risk based on quarantine studies.

Responses of Common Reed ( Phragmites australis ) to Nitrogen and Temperature Manipulations

Invasion of introduced lineage of common reed ( Phragmites australis ) into water-saturated communities in the Great Plains has modified habitats and ecosystem services. In several areas it grows alongside and out-competes its native counterpart. We investigated ecophysiological responses of the two lineages to nitrogen (N) fertilization and temperature (19°, 25°, and 32°C). Photosynthesis (A max ) did not differ between lineages at temperatures of 19° and 25°C but was higher in the native lineage at 32°C. Fertilization improved A max at all temperatures, and was more pronounced in the native than in the introduced lineage. Native P. australis had higher δ 13 C and water use efficiency (wue) compared to the introduced lineage. Differences in maximum photochemical efficiency of photosystem II (F v /F m ), carboxylation efficiency (V cmax ), and electron transport (J max ) were observed between lineages, and generally responded positively to treatments. Our results indicated that the native P. australis may better withstand water fluctuations and warmer temperatures than its introduced counterpart, and could contribute to diverse plant communities under warmer climate scenarios. In contrast, under cool temperatures, the introduced lineage has an advantage that could lead to further displacement of native species in water-saturated communities.