Assessing the potential range expansion of the exotic monk parakeet in Spain

Plecia nearctica Hardy, commonly referred to as lovebugs, is a species of march fly with a subtropical American distribution. The northern range limits of P. nearctica could alter due to climate change, which is a worldwide issue. It has been reported that flowers utilized by P. nearctica are not visited by pollinators, which may negatively impact foraging activity particularly when resources are limited. This study used 933 occurrence records of P. nearctica in the USA to predict its potential range expansion by 2050. To predict potential habitat change we applied well-established modeling procedures using both MaxEnt and geographical information system (GIS). Six environmental variables, two climate models, and two Shared Socio-economic Pathways (SSP126 and SSP585) were used in the analysis. The model performance was excellent with a high True Skilled Statistic (=0.75) value. The predicted potential distribution and range expansion of P. nearctica in 2050 includes the Gulf Coast and the Southeastern and Western regions of the USA. However, results suggest that most of the Central and Northern USA are unlikely to provide suitable habitat for this pest and have no reason for concern about interactions between pollinators and P. nearctica.

A thesis presented on the use of computer simulation models to assess the likely impacts ofnanthropogenic climate change (the qenhanced greenhouse effectq) upon the distribution andnabundance of exotic woody weeds in Australia.Invasive woody shrubs and trees are a large and increasing problem on semi-arid rangelandsnthroughout the world. In Australia, Cryptostega grandiflora and Acada nilotica are two of the mostnsignificant of these invasive plants.Climate change threatens to alter many ecologically significant factors, and has been likened to a large uncontrollable experiment. The potentially devastating impacts of these changes meannthat we need to make important decisions in the absence of rigorous unambiguous tests. Wencannot afford to wait till the experiment runs its course. The trans-scientific nature of thisnproblem means that we must rely upon simulation models that synthesise available informationnin order to understand the nature of the changes and to devise suitable strategies fornresponding to them.The impacts of climate change on the ecology of C. grandiflora and A. nilotica were investigatednusing simulation models. CLIMEX models were developed to predict the potentialndistribution of both species under current climate. The science of predicting global climatenchange is still relatively immature and the impacts of different global atmospheric emissionnscenarios are profound. This means that there remains much uncertainty surrounding futurenclimate conditions, especially at the relatively fine regional scale. Rather than attempting tonpredict the future potential distributions of these weeds based upon regional global climatenmodels, the sensitivity of the modelled distributions to future climate scenarios were explored.nThe effect of climate change will be to expand the ranges of both species in Australia towardnthe arid continental interior and in a southerly direction. The potential expansion toward thenarid interior is likely to come about as soil moisture stress is reduced due to increases in waternuse efficiency, and increased seeding and juvenile growth rates resulting from increases innatmospheric CO2. The potential southern expansion of both species will result from annextension of the growing season with increasing global temperatures. The relatively highnelevation eastern highlands of New South Wales appear to be inhospitable to both speciesnunder both current and future climate scenarios due to the frequency of frost.The potential range expansion of C. grandiflora may place additional invasion pressure upon thenQueensland Government's strategic administrative control line, as environmental conditionsnwithin the controlled area become more suitable. The potential effect of a biological controlnagent, Maravalia cryptostegae, in controlling C. grandiflora is great, severely reducing flowering bynrepeatedly defoliating the plant throughout much of its northern Australian range. However,nthe effect of climate change on M. cryptostegae has not been investigated.Climate change analytical methodology now recognises that our ability to adapt to climatenchange should be taken into account when assessing impacts. A process-based metapopulationnmodel (SPAnDX) was developed to explore the impacts of climate change on A.nnilotica populations at the paddock scale and our adaptation options. There are few economicalncontrol options (fire, riparian habitat management and livestock species) that have beennmooted for established populations of A. nilotica and similar perennial weeds. Their efficacynunder current climate depends on local climatic conditions. Climate change reduces or nullifiesnthe efficacy of all of these control options, as habitat conditions become more suitable,nincreasing the rates of invasion and the dynamic equilibrium levels of A. nilotica in eachnpaddock. The only adaptation measure likely to remain effective in the face of climate changenis the use of paddock hygiene techniques to ensure that contaminated livestock void seeds in ancontrolled area prior to transport to paddocks that do not contain A. nilotica. Whilst climatenchange is likely to increase the A. nilotica problem for infested paddocks, carbon-sequestrationnfutures markets could assist in managing the problem by providing a subsidy to harvest andnutilise A. nilotica as a carbon sink.n n n n n n n n

How the South was won: current and potential range expansion of the crested porcupine in Southern Italy

Plant species ranges are expected to shift in response to climate change, however, it is unclear how species interactions will affect range shifts. Because of the potential for enemy release of invasive nonnative plant species from species-specific soil pathogens, invasive plants may be able to shift ranges more readily than native plant species. Additionally, changing climatic conditions may alter soil microbial functioning, affecting plant–microbe interactions. We evaluated the effects of site, plant–soil microbe interactions, altered climate, and their interactions on the growth and germination of three congeneric shrub species, two native to southern and central Florida (Eugenia foetida and E. axillaris), and one nonnative invasive from south America (E. uniflora). We measured germination and biomass for these plant species in growth chambers grown under live and sterile soils from two sites within their current range, and one site in their expected range, simulating current (2010) and predicted future (2050) spring growing season temperatures in the new range. Soil microbes (microscopic bacteria, fungi, viruses and other organisms) had a net negative effect on the invasive plant, E. uniflora, across all sites and temperature treatments. This negative response to soil microbes suggests that E. uniflora’s invasive success and potential for range expansion are due to other contributing factors, e.g. higher germination and growth relative to native Eugenia. The effect of soil microbes on the native species depended on the geographic provenance of the microbes, and this may influence range expansion of these native species.

Cold temperatures are thought to be among the most important determining factors of geographic distribution for tropical and sub-tropical marine invertebrates. The Asian green mussel, Perna viridis, has been introduced into coastal waters of Florida where its current distribution is hypothesized to be limited by low temperatures during winter. Lethal and sub-lethal effects (heat shock protein/Hsp70 expression) of cold water and air temperatures were analyzed in two size classes of P. viridis from Florida in an effort to determine the effects of current and forecasted temperatures on the potential for range expansion. Mussels were exposed to water temperatures of 14, 10, 7 and 3°C for up to 30 days, or to air temperatures of 14, 7, 0 and -10°C for periods of 2 hr. Mortality was significantly increased at all water and air temperatures ≤14°C. No differences in mortality rates were observed between small (15-45 mm) and large (75-105 mm) size classes except after exposure to 7°C air, in which small mussels had higher mortality. Significant increases in Hsp70 expression were observed after a 2-hour exposure to 10°C water, but Hsp70 expression was not significantly increased at any temperatures in which mortality was not also significant. The temperature threshold for survival in this population appears to be between 10 and 14°C, suggesting that under current conditions P. viridis may already be at the northern edge of its potential range in the United States. If water temperatures increase with global climate change, northerly flowing currents may permit range expansion as temperatures allow.

Key factors influencing the occurrence and frequency of ciguatera

Modelling and predicting the potential habitat and future range expansion of invasive species can help managers to mitigate the impact of such species. Because habitat suitability and the colonization process are key determinants of range expansion, inferences drawn from invasion patterns should be based on both attributes. To predict the potential habitat and expansion rate of the invasive tree Bischofia javanica on Hahajima Island, we used simultaneous models of habitat and dispersal to estimate the effect of environment and dispersal from the source population on the current distribution. We compared the fit and the estimated magnitudes of the environment and dispersal effects in the simultaneous models with those in habitat suitability and colonization kernel models. The values of Akaike's information criterion for the simultaneous models were better than those of the habitat suitability and colonization kernel models, indicating that the current distribution of Bischofia was determined by both environment and dispersal. The simultaneous models predicted that the potential habitat of Bischofia would be larger than that predicted by the habitat suitability model. The potential habitat distribution and future invasion predicted by the simultaneous models will contribute to the development of specific landscape‐scale management plans to control this invasive species.

The impact of climate change on the distribution of Castanopsis (Fagaceae) species in south China and Indo-China region

Range expansion potential of two co-occurring invasive vines to marginal habitats in Turkey

ABSTRACTIn this study we determine favourable areas for the monk parakeet,Myiopsitta monachus, in peninsular Spain to account for its current distribution and predict its future course according to its potential range. We applied a favourability function based on generalized linear models using the presence/absence of breeding colonies of the species and the values of a set of variables on the 5167 UTM 10 × 10 km squares comprising the study area. We calculated the factor of distribution change in presences predicted by the model, and grouped the variables into explanatory factors performing a variation partitioning to assess the explanatory power of each factor. Our model included six predictors to explain the presence and absence of the species. These predictors were grouped into three factors: human activity, climate, and topography. Purely human influences accounted for 63.8% of the variation of the final model, while topographical variables explained 15.2% and climate only 5.7%. We obtained a high distribution change factor in which the presences of the species were predicted to increase between two‐ and sevenfold. Taking into account highly favourable squares, we conclude that the species is still absent in more than 72% of potential settlement areas, and thus we expect a continuous increase in the distribution of the species. Human activity is the main force moulding the distribution of the species, and lies behind its fast expansion, which is not only active, but is also passive via releases and escapes. We identified the areas of likely future expansion of the exotic monk parakeet in Spain. The pest status of the species in its native range, together to its distribution trend, should be taken into account by wildlife agencies to consider options for management.

Leandras.str. clade has around 200 species nearly restricted to eastern Brazil. Most species in this group are narrow endemics, but a few present striking disjunct distributions between eastern Brazil and Andes or Mesoamerica. Given the predominantly “montane” distribution observed in mostLeandras.str., we hypothesized that cyclical range expansions during colder Pleistocene periods, followed by local extinctions during warmer interglacial periods, could have shaped the distribution of the disjunct species in this clade. In order to gather support for this biogeographical scenario in a phylogenetic framework, the species that occur outside eastern Brazil were identified, ages of the dispersal events estimated, climatic niche models for the disjuncts were generated, and the climatic envelope of these species compared. Our results place all dispersal events from eastern Brazil to Andes or Mesoamerica during the Pleistocene. Climatic niche modeling indicates a potential range expansion during the Pleistocene colder times for the disjunct species. Although the surpassing of the “dry diagonal” could have been facilitated during glacial periods, this open corridor is an effective barrier forLeandra, given the reduced number of species that dispersed beyond an eastern Brazilian origin. Additionally, the disjunct species do not present significant differences in their climatic envelopes to the non‐disjunct species. Our results provide support to a short‐dispersion/stepping‐stone migration scenario to account for the observed disjunctions in this clade. Range expansions during Pleistocene colder periods followed by local extinctions during interglacial periods could have shaped the distribution ofLeandras.str.

Theoretical framework for assessment of risks posed to Canadian forests by invasive insect species

Many species show range expansions or contractions due to climate change induced changes in habitat suitability. In cold climates, many species that are limited by snow are showing range expansions due to reduced winter severity. The European polecat Mustela putorius occurs over large parts of Europe with its northern range limit in southern Fennoscandia. However, it is to date unknown what factors limit polecat distribution. We thus investigated whether climate or land‐use variables are more important in determining the habitat suitability for polecats in Sweden. We hypothesized that 1) climatic factors, especially the yearly number of snow days, drive habitat suitability for polecats, and that, 2) as the number of snow days is predicted to decline in the near future, habitat suitability in northern Sweden will increase. We used a combination of sightings data and a selection of national maps of environmental factors to test these hypotheses using Maxent models. We also used maps of future climate predictions (2021–2050 and 2063–2098) to predict future habitat suitability. The number of snow days was the most important factor, negatively determining habitat suitability for polecats, as expected. Consequently, the predictions showed an increase in suitable habitat both in the current distribution range and in northern Sweden, especially along the coast of the Baltic Sea. Our results suggest that the polecat distribution is limited by snow and that reduced snow cover will likely result in a northward range expansion. However, the exact mechanisms for how snow limits polecats are still poorly understood. The potential range expansion might result in a population increase of the Scandinavian polecat population, in contrast to many populations elsewhere in Europe, where numbers are declining. Due to polecat predation, the expansion of the species might have cascading effects on other wildlife populations.

In estuaries, salinity is believed to limit the colonization of brackish water habitats by freshwater species. Blue catfish Ictalurus furcatus, recognized as a freshwater species, is an invasive species in tidal rivers of the Chesapeake Bay. Salinity tolerance of this species, though likely to determine its potential range expansion and dispersal in estuarine habitats, is not well-known. To address this issue, we subjected blue catfish to a short-term salinity tolerance experiment and found that this species tolerates salinities higher than most freshwater fishes and that larger blue catfish tolerate elevated salinities for longer periods compared with smaller individuals. Our results are supported by spatially extensive, long-term fisheries surveys in the Chesapeake Bay region, which revealed a gradual (1975–2017) down-estuary range expansion of blue catfish from tidal freshwater areas to habitats exceeding 10 psu [practical salinity units] and that large blue catfish (> 200 mm fork length) occur in salinities greater than 10 psu in Chesapeake Bay tributaries. Habitat suitability predictions based on our laboratory results indicate that blue catfish can use brackish habitats to colonize new river systems, particularly during wet months when salinity decreases throughout the tidal rivers of the Chesapeake Bay.

As a result of low decomposition rates, high-latitude ecosystems store large amounts of carbon. Litter decomposition in these ecosystems is constrained by harsh abiotic conditions, but also by the absence of macro-detritivores. We have studied the potential effects of their climate change-driven northward range expansion on the decomposition of two contrasting subarctic litter types. Litter of Alnus incana and Betula pubescens was incubated in microcosms together with monocultures and all possible combinations of three functionally different macro-detritivores (the earthworm Lumbricus rubellus, isopod Oniscus asellus, and millipede Julus scandinavius). Our results show that these macro-detritivores stimulated decomposition, especially of the high-quality A. incana litter and that the macro-detritivores tested differed in their decomposition-stimulating effects, with earthworms having the largest influence. Decomposition processes increased with increasing number of macro-detritivore species, and positive net diveristy effects occurred in several macro-detritivore treatments. However, after correction for macro-detritivore biomass, all interspecific differences in macro-detritivore effects, as well as the positive effects of species number on subarctic litter decomposition disappeared. The net diversity effects also appeared to be driven by variation in biomass, with a possible exception of net diversity effects in mass loss. Based on these results, we conclude that the expected climate change-induced range expansion of macro-detritivores into subarctic regions is likely to result in accelerated decomposition rates. Our results also indicate that the magnitude of macro-detritivore effects on subarctic decomposition will mainly depend on macro-detritivore biomass, rather than on macro-detritivore species number or identity.Electronic supplementary materialThe online version of this article (doi:10.1007/s00442-011-2051-8) contains supplementary material, which is available to authorized users.