Distribution Range Shifts Research Articles

The role of East Asian monsoon system in shaping population divergence and dynamics of a constructive desert shrub Reaumuria soongarica.

Both of the uplift of Qinghai-Tibet Plateau (QTP) and the development of East Asian monsoon system (EAMS) could have comprehensively impacted the formation and evolution of Arid Central Asia (ACA). To understand how desert plants endemic to ACA responded to these two factors, we profiled the historical population dynamics and distribution range shift of a constructive desert shrub Reaumuria soongarica (Tamaricaceae) based on species wide investigation of sequence variation of chloroplast DNA and nuclear ribosomal ITS. Phylogenetic analysis uncovered a deep divergence occurring at ca. 2.96 Mya between the western and eastern lineages of R. soongarica, and ecological niche modeling analysis strongly supported that the monsoonal climate could have fragmented its habitats in both glacial and interglacial periods and impelled its intraspecific divergence. Additionally, the population from the east monsoonal zone expanded rapidly, suggesting that the local monsoonal climate significantly impacted its population dynamics. The isolation by distance tests supported strong maternal gene flow along the direction of the East Asian winter monsoon, whose intensification induced the genetic admixture along the latitudinal populations of R. soongarica. Our results presented a new case that the development of EAMS had prominently impacted the intraspecific divergence and population dynamics of this desert plant.

Winners and losers of climate change for the genus Merodon (Diptera: Syrphidae) across the Balkan Peninsula

The implementation of species distribution models on the research of species response to climate change has increased due to the growing vulnerability and extinction rates of various taxa. Reported declines of pollinator population sizes and diversity due to global changes may negatively affect the services they provide. Considering the importance of hoverflies as pollinators, we predict the climate change effect on the potential distribution range of selected species of the genus Merodon Meigen, 1803. We used two climate models (ECHAM5, HadCM3) and three climate change scenarios (optimistic, modest, pessimistic), under two time frames (2050 and 2080). We predicted the species spatial distribution as well as the species richness and the percentage turnover for two extreme dispersal hypotheses (limited, unlimited). The analysis was implemented using an ensemble forecasting modelling approach. Species adapted to higher altitudes (i.e. with lower temperature requirements) and/or latitudes were predicted to be more vulnerable to climate change vs. species able to tolerate a wider range of temperatures, by losing a higher percentage of climatically suitable area. Significant differences in distribution ranges were found between mountainous and the remaining species groups each one considered separately (viz. climate-generalists, Mediterranean, and east Mediterranean). Southern Balkans were predicted to experience a preservation of species assemblage across all climate change models, scenarios and dispersal assumptions, while the central and northwestern parts were predicted to be subject to an increased change of their species composition. We emphasize the importance of forecasting distribution shifts of a high number of species for the development of conservation strategies. Furthermore, due to the dependence of Merodon fly larvae on geophytes, we highlight the necessity of incorporating biotic interactions to model the potential distribution range shifts of these hoverfly species.

Biogeography of the smooth snake (Coronella austriaca): origin and conservation of the northernmost population

Understanding historical range expansions and population demography can be crucial for the conservation and management of endangered species. In doing so, valuable information can be obtained regarding, for example, the identification of isolated populations, associations to particular habitats and distribution range shifts. As poikilotherms, snakes are vulnerable to environmental changes that can greatly shape their distribution ranges. Here we used mitochondrial data to elucidate the origin of the smooth snake population in Aland island, which is the northernmost location where the species is found. In Aland, we used mitochondrial and microsatellite data to fine-map its spatial genetic structure, infer its demographic dynamics and determine its effective population size. We found three independent lineages, which expanded north from Iberian, the Balkans and Caucasus regions. The central lineage originating in the Balkans was the only one that reached Scandinavia. The Aland population belongs to this lineage and potentially colonized the island from the west via Sweden. This population appeared to be critically small and fragmented into two genetically isolated subpopulations. We discuss our results in light of previous findings regarding colonization routes in Europe and Scandinavia. Moreover, we discuss the origin and current genetic status of the Aland population relative to other co-occurring snakes and suggest conservation measures based on our findings. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 114, 426–435.

Climate change and lizards: changing species' geographic ranges in Patagonia

Ectothermic organisms strongly depend on temperature, making them an excellent model to study the impact of global climatic change (GCC). Under global warming, species may be forced to move toward colder environments, such as higher latitudes, higher elevations or both. However, several studies show that responses may vary significantly in different groups of species. Therefore, it is unclear whether species' current distribution range sizes will be affected in future climatic scenarios. In addition to the specific possible effect of range size chan- ges, the potential consequences of distributional range shifts also should be considered. Here, our aim is to assess whether GCC may affect a group of Liolaemus lizard species based on their current geographic distribution range size and whether the effect is uniform across all species using species distribution models (SDMs). Our results show that range boundaries of the fourteen species switch toward higher altitude and latitude in future scenarios. Additionally, there is not a unique pattern in terms of increase or decrease in potential range for lizards in Pata- gonia in future scenarios. Finally, our results show that the original distribution range size is determinant for the resultant SDMs projections, suggesting that species with a high degree of endemicity may be susceptible to a greater impact of GCC.

A preliminary survey of altitudinal variation in two ground wētā species, Hemiandrus maculifrons (Walker) and Hemiandrus pallitarsis (Walker) (Orthoptera: Anostostomatidae)

Species’ ranges along altitudinal clines are probably influenced by their ability to adapt to a range of abiotic factors. Physical adaptations in response to lower temperatures at higher altitudes often include changes in body size. We investigated the distribution and potential change in body size with altitude of two species of ground wētā, Hemiandrus maculifrons and Hemiandrus pallitarsis in the Moehau Ecological Area on the Coromandel Peninsula, North Island, New Zealand. Over eight nights of searching, 17 adult H. maculifrons and 28 adult H. pallitarsis were found. Hemiandrus maculifrons was the smaller of the two species and was found at higher altitudes compared with H. pallitarsis (91–577 m and 27–207 m, respectively). No ground wētā were caught in baited and unbaited live-catch pitfall traps (40 set at 211–242 m above sea level; 40 at 620–626 m above sea level). Despite what appeared to be a tendency for the size of male H. maculifrons to increase with altitude, we found no evidence of intraspecific variation in body size with altitude although sample sizes were small. Nevertheless, these two species of ground wētā appear well suited to further investigations into aspects associated with factors that influence body size, distributional range shifts and climate change.

Priority effects can lead to underestimation of dispersal and invasion potential

Molecular analyses are frequently used to assess biological gene flow and dispersal, yet recent data suggest that the operation of density-dependent priority effects often leads to underestimation of species movement patterns and associated invasive potential. Although individual movement is broadly considered to promote connectivity among populations, emerging genetic evidence on a range of scales indicates that it often fails to do so; instead, it can be a strategy that allows first colonizers to wedge a ‘foot in the door’ when new space becomes available. Founding lineages can then rapidly dominate, blocking colonization by later arrivals; subsequent invasion opportunities may be contingent on the extirpation of locals. Many contemporary studies, however, ignore the role of such density-dependent priority effects, and thus fail to assess major differences between movement and establishment. Understanding the role of these processes in the successful establishment of dispersing organisms is critical if we are to predict distributional range shifts and deal with invasive pest species.

Vital survivors: low genetic variation but high germination in glacial relict populations of the typical rock plant Draba aizoides

Glacial relict populations are isolated remnants of arctic-alpine species resulting from shifts of the distribution range during glaciations. Recently, the conservation value of relict populations has been emphasized, since they are adapted to stressful ecological conditions, which may be important for future distribution range shifts due to climate change. However, glacial relict populations have strongly been affected by historical fragmentation processes. Limited genetic variation and reduced reproduction can, therefore, be postulated for glacial relict populations. In our study we tested these assumptions. We investigated central European populations of the typical rock plant Draba aizoides from the Alps (considered as a core distribution area) and from the Swabian Alb, the Southern and Northern Franconian Jura (where its populations are considered glacial relict populations). We analysed genetic variation using molecular markers AFLPs and studied the reproduction of the populations in germination experiments. Glacial relict populations were genetically less variable and strongly differentiated, but they exhibited higher germination than populations from the Alps. From our results it can be concluded that glacial relict populations may have limited genetic variation, but they do not necessarily exhibit a limited reproductive capacity. Glacial relict populations are, therefore, vital survivors of the Pleistocene, which deserve full conservation attention, especially against the background of future climate change.

Post-Glacial Spatial Dynamics in a Rainforest Biodiversity Hot Spot

Here we investigate the interaction between ecology and climate concerning the distribution of rainforest species differentially distributed along altitudinal gradients of eastern Australia. The potential distributions of the two species closely associated with different rainforest types were modelled to infer the potential contribution of post-glacial warming on spatial distribution and altitudinal range shift. Nothofagus moorei is an integral element of cool temperate rainforest, including cloud forests at high elevation. This distinct climatic envelope is at increased risk with future global warming. Elaeocarpus grandis on the other hand is a lowland species and typical element of subtropical rainforest occupying a climatic envelope that may shift upwards into areas currently occupied by N. moorei. Climate envelope models were used to infer range shift differences between the two species in the past (21 thousand years ago), current and future (2050) scenarios, and to provide a framework to explain observed genetic diversity/structure of both species. The models suggest continuing contraction of the highland cool temperate climatic envelope and expansion of the lowland warm subtropical envelope, with both showing a core average increase in elevation in response to post-glacial warming. Spatial and altitudinal overlap between the species climatic envelopes was at a maximum during the last glacial maximum and is predicted to be a minimum at 2050.

Responses of insects to the current climate changes: from physiology and behavior to range shifts

Responses of insects to the current climate changes: from physiology and behavior to range shifts

Strengthening forecasts of climate change impacts with multi‐model ensemble averaged projections using MAGICC/SCENGEN 5.3

Climate output from general circulation models (GCMs) is being used with increasing frequency to explore potential climate change impacts on species’ distributional range shifts and extinction probability. However, different GCMs do not perform equally well in their ability to hindcast the key climatic factors that potentially influence species distributions. Previous research has demonstrated that multi‐model ensemble forecasts perform better than any single GCM in simulating observed conditions at a global scale. MAGICC/SCENGEN 5.3 is a freeware climate model ‘emulator’ that generates multi‐model ensemble forecasts, conditional on regional and/or global performance, for up to twenty GCMs. In combination with a new application ‘M/SGridder’, this software can be used to produce down‐scaled ensemble forecasts, which minimize climate‐model‐related uncertainty, for a range of ecological problems.

Projection of climate change effects on the potential distribution of Abeliophyllum distichum in Korea

Changes in biota, species distribution range shift and catastrophic climate influence due to recent global warming have been observed during the last century. Since global warming affects various sectors, such as agriculture and vegetation, it is important to predict more accurate impact of future climate change. The purpose of this study is to examine the observed distribution of Abeliophyllum distichum in the Korean peninsula. For this purpose, two period (present and future) climate data were used. Mean data between 1950 and 2000, were used as the present value and the year 2050 and 2080 data from A1B senario in IPCC SRES were used for the future value. Potential habitation is analyzed by MaxEnt(Maximum Entropy model), and Abeliophyllum distichum’s coordinates data were used as a dependent variable and independent variables are composed of environmental data such as BioClim, altitude, aspect and slope. The result of six types GCM mean calculation, the potential habitability decreased by 40-60% of the average existing distribution. The methodogies and results of this resarch can be applicable to the climate changing adaptation stratiegies for the biodiversity conservation.

Multi-source analysis reveals latitudinal and altitudinal shifts in range of Ixodes ricinus at its northern distribution limit

BackgroundThere is increasing evidence for a latitudinal and altitudinal shift in the distribution range of Ixodes ricinus. The reported incidence of tick-borne disease in humans is on the rise in many European countries and has raised political concern and attracted media attention. It is disputed which factors are responsible for these trends, though many ascribe shifts in distribution range to climate changes. Any possible climate effect would be most easily noticeable close to the tick's geographical distribution limits. In Norway- being the northern limit of this species in Europe- no documentation of changes in range has been published. The objectives of this study were to describe the distribution of I. ricinus in Norway and to evaluate if any range shifts have occurred relative to historical descriptions.MethodsMultiple data sources - such as tick-sighting reports from veterinarians, hunters, and the general public - and surveillance of human and animal tick-borne diseases were compared to describe the present distribution of I. ricinus in Norway. Correlation between data sources and visual comparison of maps revealed spatial consistency. In order to identify the main spatial pattern of tick abundance, a principal component analysis (PCA) was used to obtain a weighted mean of four data sources. The weighted mean explained 67% of the variation of the data sources covering Norway's 430 municipalities and was used to depict the present distribution of I. ricinus. To evaluate if any geographical range shift has occurred in recent decades, the present distribution was compared to historical data from 1943 and 1983.ResultsTick-borne disease and/or observations of I. ricinus was reported in municipalities up to an altitude of 583 metres above sea level (MASL) and is now present in coastal municipalities north to approximately 69°N.ConclusionI. ricinus is currently found further north and at higher altitudes than described in historical records. The approach used in this study, a multi-source analysis, proved useful to assess alterations in tick distribution.

Ecological correlates of distribution change and range shift in butterflies

1. In order to be effective custodians of biodiversity, one must understand what ecological characteristics predispose species to population decline, range contraction, and, eventually, to extinction. 2. The present paper analyses distribution change (area of occupancy) and range shift (extent and direction) of the threatened and non-threatened butterfly species in Finland, and identifies species-specific ecological characteristics promoting changes in distribution and range. 3. Overall, the range of butterflies has shifted along the climatic isotherms, suggesting that climate change has influenced species’ ranges. Interestingly, though, threatened species have moved very little and not to any consistent direction. 4. The most obvious pattern observed is that ecological specialisation, be it at larval or at adult stage, promotes distribution decline. The analysis further revealed that poor dispersal ability and large body size predispose species to distribution decline. 5. Species ecological traits influence their susceptibility to distribution change and range shift. Thus, as a result of climate change, biological communities may become over-represented by highly dispersive generalists. It is argued that with the kind of ecological information provided here, managers should become proactive and initiate the necessary measures for conservation of species when their populations are still viable instead of reacting only to the imminent extinction risk when it already may be too late.

Individualistic species limitations of climate‐induced range expansions generated by meso‐scale dispersal barriers

AbstractAim Evidence indicates that species are responding to climate change through distributional range shifts that track suitable climatic conditions. We aim to elucidate the role of meso‐scale dispersal barriers in climate‐tracking responses.Location South coast of England (the English Channel).Methods Historical distributional data of four intertidal invertebrate species were logistically regressed against sea surface temperature (SST) to determine a climate envelope. This envelope was used to estimate the expected climate‐tracking response since 1990 along the coast, which was compared with observed range expansions. A hydrodynamic modelling approach was used to identify dispersal barriers and explore disparities between expected and observed climate tracking.Results Range shifts detected by field survey over the past 20 years were less than those predicted by the changes that have occurred in SST. Hydrodynamic model simulations indicated that physical barriers produced by complex tidal currents have variably restricted dispersal of pelagic larvae amongst the four species.Main conclusions We provide the first evidence that meso‐scale hydrodynamic barriers have limited climate‐induced range shifts and demonstrate that life history traits affect the ability of species to overcome such barriers. This suggests that current forecasts may be flawed, both by overestimating range shifts and by underestimating climatic tolerances of species. This has implications for our understanding of climate change impacts on global biodiversity.

Recurrent, thermally-induced shifts in species distribution range in the Humboldt current upwelling system

El Niño-Southern Oscillation (ENSO) is a global climate variablility, which fundamentally influences environmental patterns of the Humboldt Current System (HCS) off Chile and Peru. The surf clams Donax obesulus and Mesodesma donacium are dominant and highly productive bivalves of exposed sandy beaches of the HCS. Existing knowledge indicates that El Niño (EN, warm phase of ENSO) and La Niña (LN, cold phase of ENSO) affect populations of both species in a different way, although understanding of the mechanisms underlying these effects is still lacking. The aim of this study was to test hypotheses attempting to explain field observations on the effect of strong EN or LN events by using controlled experimental conditions. Growth and mortality rates of both species were registered during a four-week experiment under EN temperature conditions, normal temperature conditions and LN temperature conditions. While D. obesulus exhibited reduced growth and higher mortality under LN conditions, M. donacium showed reduced growth and higher mortality under EN conditions. The results clearly indicate different temperature tolerance windows for each species, possibly reflecting the evolutionary origins of the Donacidae and Mesodesmatidae in regions with contrasting temperature regimes. These results provide experimental support for previous hypotheses suggesting that thermal tolerance is the driving factor behind observed changes in the species distributions of D. obesulus and M. donacium during the extreme phases of ENSO.

The concept of population in clonal organisms: mosaics of temporally colonized patches are forming highly diverse meadows of Zostera marina in Brittany

Seagrasses structure some of the world's key coastal ecosystems presently in decline due to human activities and global change. The ability to cope with environmental changes and the possibilities for shifts in distribution range depend largely on their evolvability and dispersal potential. As large-scale data usually show strong genetic structure for seagrasses, finer-grained work is needed to understand the local processes of dispersal, recruitment and colonization that could explain the apparent lack of exchange across large distances. We aimed to assess the fine-grained genetic structure of one of the most important and widely distributed seagrasses, Zostera marina, from seven meadows in Brittany, France. Both classic population genetics and network analysis confirmed a pattern of spatial segregation of polymorphism at both regional and local scales. One location exhibiting exclusively the variety 'angustifolia' did not appear more differentiated than the others, but instead showed a central position in the network analysis, confirming the status of this variety as an ecotype. This phenotypic diversity and the high allelic richness at nine microsatellites (2.33-9.67 alleles/locus) compared to levels previously reported across the distribution range, points to Brittany as a centre of diversity for Z. marina at both genetic and phenotypic levels. Despite dispersal potential of several 100 m, a significant pattern of genetic differentiation, even at fine-grained scale, revealed 'genetic patchiness'. Meadows seem to be composed of a mosaic of clones with distinct origins in space and time, a result that calls into question the accuracy of the concept of populations for such partially clonal species.

Population history and gene dispersal inferred from spatial genetic structure of a Central African timber tree, Distemonanthus benthamianus (Caesalpinioideae).

African rainforests have undergone major distribution range shifts during the Quaternary, but few studies have investigated their impact on the genetic diversity of plant species and we lack knowledge on the extent of gene flow to predict how plant species can cope with such environmental changes. Analysis of the spatial genetic structure (SGS) of a species is an effective method to determine major directions of the demographic history of its populations and to estimate the extent of gene dispersal. This study characterises the SGS of an African tropical timber tree species, Distemonanthus benthamianus, at various spatial scales in Cameroon and Gabon. Displaying a large continuous distribution in the Lower Guinea domain, this is a model species to detect signs of past population fragmentation and recolonization, and to estimate the extent of gene dispersal. Ten microsatellite loci were used to genotype 295 adult trees sampled from eight populations. Three clearly differentiated gene pools were resolved at this regional scale and could be linked to the biogeographical history of the region, rather than to physical barriers to gene flow. A comparison with the distribution of gene pools observed for two other tree species living in the same region invalidates the basic assumption that all species share the same Quaternary refuges and recolonization pathways. In four populations, significant and similar patterns of SGS were detected. Indirect estimates of gene dispersal distances (sigma) obtained for three populations ranged from 400 to 1200 m, whereas neighbourhood size estimates ranged from 50 to 110.

Predicting distribution patterns and recent northward range shift of an invasive aquatic plant: Elodea canadensis in Europe

Climate data and distribution data for the Canadian waterweed Elodea canadensis Michx. from North America, whole Europe and Finland were used to investigate the ability of bioclimatic envelope models to predict the distribution range and recent northward range shift of the species in Europe. Four different main types of models were developed using the North American data, including either three ‘baseline’ climate variables (growing degrees days, temperature of the coldest month, water balance) or an extended set of seven climate variables, both averaged either over a 30 year time slice or a longer 90 year time slice. Ten different random selections of pseudo-absences were generated from the North American data, on the basis of which ten separate generalized additive models (GAMs) were developed for each main model type. All the 40 developed GAMs were applied first to North America and then transferred to whole Europe and Finland. All the models showed a statistically highly significant accuracy in the three study areas. Although the differences among the four main model types were only minor, the two extended model types showed on average statistically better performance than the two baseline models based on Bayesian information criterion (BIC) values, the amount of deviance explained by the models, resubstitution validation and four-fold cross-validation in North America. They also provided slightly more accurate predictions of climatically suitable area for Elodea canadensis in Finland both in 1961–1984 and 1985–2006. However, the projections from the individual extended models were more variable than projections from the baseline models. Thus model predictions based on a variety of predictor variables but only one selection of pseudoabsences may be subject to biases, and outputs from multiple models should be investigated to better account for uncertainties in modelling. Overall, our results suggest that more attention should be paid to the careful selection of predictor variables and the use of multiple pseudo-absence sets in the ecological niche modelling in order to increase the reliability of the projections of the range shifts of invasive species.

Unravelling the effects of temperature, latitude and local environment on the reproduction of forest herbs

ABSTRACTAim To investigate the effect of temperature, latitude and local environment on the reproductive traits of widespread perennial forest herbs to better understand the potential impacts of rising temperatures on their population dynamics and colonization capacities.Location Six regions along a latitudinal gradient from France to Sweden.Methods Within each region, we collected data from three to five populations of up to six species. For each species, several variables were recorded in each region (temperature, latitude) and population (local abiotic and biotic environmental variables), and seed production and germination were estimated. Resource investment in reproduction (RIR) was quantified as seed number × seed mass, while germinable seed output (GSO) was expressed as seed number × germination percentage. We performed linear regression and mixed effect models to investigate the effects of temperature (growing degree hours), latitude and local abiotic and biotic environment on RIR and GSO.Results Temperature and latitude explained most of the variation in RIR and GSO for early flowering species with a northerly distribution range edge (Anemone nemorosa, Paris quadrifolia and Oxalis acetosella). Reproduction of the more southerly distributed species (Brachypodium sylvaticum, Circaea lutetiana and Primula elatior), in contrast, was independent of temperature/latitude. In the late summer species, B. sylvaticum and C. lutetiana, variation in RIR and GSO was best explained by local environmental variables, while none of the investigated variables appeared to be related to reproduction in P. elatior.Main conclusions We showed that reproduction of only two early flowering, northerly distributed species was related to temperature. This suggests that the potential reproductive response of forest herbs to climate warming partly depends on their phenology and distribution, but also that the response is to some extent species dependent. These findings should be taken into account when predictions about future shifts in distribution range are made.

Pleistocene distribution range shifts were accompanied by breeding system divergence within Hornungia alpina (Brassicaceae) in the Alps

Impact of glacial history on the phylogeography of silicate-dwelling plants of the European Alps has been particularly well studied, whereas virtually no data are available for species growing on different bedrock types, as for Hornungia alpina. Bayesian clustering of AFLP data only partly support the distinction of three subspecies as morphologically defined. Whereas the phylogeographical N-group corresponds to subsp. alpina, the congruence of the SW-group and SE-group with subsp. brevicaulis, and subsp. austroalpina, respectively, is limited. High levels of rarity and genetic diversity in the N-group suggest Pleistocene survival along the outer margin of the Alpine arc. For subsp. brevicaulis we suggest a single origin from a refugium in the Southwestern Alps, whereas subsp. austroalpina might have originated twice in the Southern and Southeastern Alps. Different levels of genetic diversity and partitioning of genetic variation indicate a divergence in breeding system, which is corroborated by pollinator exclusion experiments revealing self-incompatibility in the N-group and autonomous selfing in the SE-group.