Range Expansion

Anthropogenic influences on the biosphere since the advent of the industrial age are increasingly causing global changes. Climatic change and the rising concentration of greenhouse gases in the atmosphere are ranking high in scientific and public agendas, and other components of global change are also frequently addressed, among which are the introductions of non indigenous species (NIS) in biogeographic regions well separated from the donor region, often followed by spectacular invasions. In the marine environment, both climatic change and spread of alien species have been studied extensively; this review is aimed at examining the main responses of ecosystems to climatic change, taking into account the increasing importance of biological invasions.

We assess the potential impact of climate change on plant diversity in the Cape Floristic Region (CFR) and its interaction with land transformation that has already occurred in the region. Predictions were made both at the scale of the Fynbos Biome (the dominant vegetation assemblage in the CFR) and for selected Proteaceae species. Bioclimatic modelling identified parts of the biome at particular risk from climate change. Species-level modelling (Generalised Additive Modelling) was done for 28 Proteaceae species selected from areas at high risk of biome loss, revealing individualistic range changes in a pattern broadly consistent with biome modelling results. Most species experienced potential range contractions (17 of 28), of which five showed range elimination. Several species (11 of 28) showed potential range expansions. For species showing range contractions, current land transformation had less impact on future potential ranges than did climate change, because many species ranges shifted to higher altitudes where land transformation is currently less prevalent. Fewer than half of the high-risk species showed overlap between current and future potential range, showing that propagule transport, establishment of species in novel ranges and conservation of landscape linkages will be critical for maintenance of biodiversity. Methods described here provide useful forecasts of potential climate change impacts that could guide conservation responses, but results need cautious interpretation in the light of the many assumptions underlying the techniques used.

Since the 1920s, population geneticists have had measures that describe how genetic variation is distributed spatially within a species' geographical range. Modern genetic survey techniques frequently yield information on the evolutionary relationships among the alleles or haplotypes as well as information on allele frequencies and their spatial distributions. This evolutionary information is often expressed in the form of an estimated haplotype or allele tree. Traditional statistics of population structure, such as F statistics, do not make use of evolutionary genealogical information, so it is necessary to develop new statistical estimators and tests that explicitly incorporate information from the haplotype tree. One such technique is to use the haplotype tree to define a nested series of branches (clades), thereby allowing an evolutionary nested analysis of the spatial distribution of genetic variation. Such a nested analysis can be performed regarding the geographical sampling locations either as categorical or continuous variables (i.e. some measure of spatial distance). It is shown that such nested phylogeographical analyses have more power to detect geographical associations than traditional, nonhistorical analyses and, as a consequence, allow a broader range of gene-flow parameters to be estimated in a precise fashion. More importantly, such nested analyses can discriminate between phylogeographical associations due to recurrent but restricted gene flow vs. historical events operating at the population level (e.g. past fragmentation, colonization, or range expansion events). Restricted gene flow and historical events can be intertwined, and the cladistic analyses can reconstruct their temporal juxtapositions, thereby yielding great insight into both the evolutionary history and population structure of the species. Examples are given that illustrate these properties, concentrating on the detection of range expansion events. The haplotype network for haplotypes at the alcohol dehyrogenase locus of Drosophila melanogaster from with the nesting design of . Each line in the network represents a single mutational change. 0 indicates an interior node in the network that was not present in the sample; that is, these are inferred intermediate haplotypes between two nearest neighbour haplotypes in the network that differed by two or more mutations. Haplotype numbers are those given in , although haplotype 20 in that study is excluded in this analysis. Haplotype 20 came from a single line from Japan. All other haplotypes came from the eastern USA, and the states in which they were collected are indicated after the haplotype number. Thin-lined polygons indicate the haplotypes grouped together into 1-step clades, medium-lined polygons indicate the 1-step clades nested together into 2-step clades, and the thick line in the middle indicates the 2-step clades nested together into 3-step clades.

Urbanisation and climate change are two global change processes that affect animal distributions, posing critical threats to biodiversity. Due to its versatile ecology and synurbic habits, Kuhl's pipistrelle (Pipistrellus kuhlii) offers a unique opportunity to explore the relative effects of climate change and urbanisation on species distributions. In a climate change scenario, this typically Mediterranean species is expected to expand its range in response to increasing temperatures. We collected 25,132 high-resolution occurrence records from P. kuhlii European range between 1980 and 2013 and modelled the species' distribution with a multi-temporal approach , using three bioclimatic variables and one proxy of urbanisation. Temperature in the coldest quarter of the year was the most important factor predicting the presence of P. kuhlii and showed an increasing trend in the study period; mean annual precipitation and precipitation seasonality were also relevant, but to a lower extent. Although urbanisation increased in recently colonised areas, it had little effect on the species' presence predictability. P. kuhlii expanded its geographical range by about 394 % in the last four decades, a process that can be interpreted as a response to climate change.

Geographic changes in species distributions toward traditionally cooler climes is one hypothesized indicator of recent global climate change. We examined distribution data on 56 bird species. If global warming is affecting species distributions across the temperate northern hemisphere, these data should show the same northward range expansions of birds that have been reported for Great Britain. Because a northward shift of distributions might be due to multidirectional range expansions for multiple species, we also examined the possibility that birds with northern distributions may be expanding their ranges southward. There was no southward expansion of birds with a northern distribution, indicating that there is no evidence of overall range expansion of insectivorous and granivorous birds in North America. As predicted, the northern limit of birds with a southern distribution showed a significant shift northward (2.35 km/year). This northward shift is similar to that observed in previous work conducted in Great Britain: the widespread nature of this shift in species distributions over two distinct geographical regions and its coincidence with a period of global warming suggests a connection with global climate change. Distribución Reproductiva de Especies de Aves Norte Americanas en Movimiento Hacia el Norte como Resultado del Cambio Climático Resumen: Los cambios en la distribución de las especies hacia climas tradicionalmente más frescos es un indicador hipotético del cambio climático global reciente. Examinamos los datos de distribución de 56 especies de aves. Si el calentamiento global está afectando la distribución de especies en el Hemisferio Norte templado, estos datos deberían mostrar la misma expansión en la distribución hacia el norte de aves que se han reportado para Gran Bretaña. Debido a que un cambio hacia el norte en las distribuciones puede deberse a expansiones multidireccionales en la distribución de múltiples especies, también examinamos la posibilidad de que aves con distribuciones norteñas estén expandiendo sus distribuciones hacia el sur. No hubo expansión hacia el sur de aves con una distribución norteña, lo que indica que no hay evidencia de una expansión de distribución general de aves insectívoras y granívoras en Norte América. Como se predijo, el límite norteño de aves con distribución sureña mostró un cambio significativo hacia el norte (2.35 km/año). Esta expansión hacia el norte es similar a la observada en trabajos previos realizados en Gran Bretaña: el carácter generalizado de este cambio en las distribuciones de especies en dos regiones geográficas distintas y su coincidencia con un período de calentamiento global sugiere una conexión con el cambio climático global. Palabras Clave: aves de Norteamérica, calentamiento global, cambio climático, cambios de distribución, distribución de aves, distribución reproductiva * Current address: Forestry and Wildlife Sciences Building,

The conservation of bison in Yellowstone National Park, from near extinction in the late 19th century to a recent high of 5000, has led to long-term societal conflict regarding perceived overabundance, transboundary movements, and potential transmission of brucellosis from bison to livestock. We synthesized available information to address two central questions in this debate: (1) has the Yellowstone bison population surpassed numbers that can be supported by the forage base in the park; and (2) why do some bison move outside the park during winter, even when numbers are below food-limited carrying capacity? A spatially-explicit model of the system that integrated abiotic variables with biotic processes indicated bison have not reached a theoretical food-limited carrying capacity of 6200 in Yellowstone National Park. However, more bison began to migrate earlier to lower-elevation winter ranges as numbers increased and climatic factors interacted with density to limit nutritional intake and foraging efficiency. A gradual expansion of the winter range as bison numbers increased enabled relatively constant population growth and increased food-limited carrying capacity. Current management actions attempt to preserve bison migration to essential winter range areas within and adjacent to the park, while actively preventing dispersal and range expansion to outlying areas via hazing and removals (i.e., dispersal sink). A population of 2500-4500 bison should satisfy collective interests concerning the park's forage base, bison movement ecology, retention of genetic diversity, brucellosis risk management, and prevailing social conditions.

The first expected symptoms of a climate change-generated biodiversity crisis are range contractions and extinctions at lower elevational and latitudinal limits to species distributions. However, whilst range expansions at high elevations and latitudes have been widely documented, there has been surprisingly little evidence for contractions at warm margins. We show that lower elevational limits for 16 butterfly species in central Spain have risen on average by 212 m (± SE 60) in 30 years, accompanying a 1.3°C rise (equivalent to c. 225 m) in mean annual temperature. These elevational shifts signify an average reduction in habitable area by one-third, with losses of 50-80% projected for the coming century, given maintenance of the species thermal associations. The results suggest that many species have already suffered climate-mediated habitat losses that may threaten their long-term chances of survival.

Wild deer can feature in the epidemiology of a wide range of livestock and human diseases in the United Kingdom by representing a source of disease via various transmission routes. This review highlights current and possible future infections of deer in the UK which may have an impact on livestock and/or human health. Increases in deer abundance as well as range expansion are likely to exacerbate the potential for disease persistence due to the formation of multi-species deer assemblages, which may act as disease reservoirs. Climatic changes are likely to have a direct impact on the presence and abundance of various pathogens and their vectors, so that with a warming climate exotic diseases may play a role in future UK livestock and wildlife disease management. This paper highlights the need for a monitoring strategy for wildlife diseases, in particular infections in wild deer, in the UK.

An important first step in assessing the possible effects of climate change on the risk of mosquito-borne disease in Canada requires an understanding of the potential shifts in the geographic range of mosquito populations under projected future climate. Risk maps of potential habitat suitability of the mosquito Culex pipiens, an important vector of West Nile and other arboviruses, were created using logistic regression models under conditions of current and projected climate. Current predictions for Culex pipiens distribution are that suitable climatic conditions for the species can be found in southern Ontario, Quebec, New Brunswick, Nova Scotia, Prince Edward Island and southern parts of Newfoundland and Labrador. Projected ranges of the mosquito were obtained using output from models of the Coupled Global Climate Model of the Canadian Centre for Climate Modelling and Analysis and the National Center for Atmospheric Research Community Climate System Model. Using both models, predictions of Culex pipiens range expansion were found for areas further north of the current estimated distribution in Ontario, Quebec, New Brunswick and Newfoundland and Labrador as well as increasing potential habitat suitability in parts of the prairies (Manitoba, Saskatchewan and Alberta) from the 2020s through to 2080s. The degree of range expansion varied according to the greenhouse gas emissions scenario ('A2'high emissions scenario and 'B1' -low emissions scenario) used in calibrating the climate models. These findings suggest that through its effects on Culex pipiens survival and geographic range, climate change may broaden the range of some mosquito-borne pathogens and as a result expose new human populations to these disease-causing agents.

FOREWORD Discussions of nonnative plant species and wildfire present excellent opportunities to integrate knowledge from different disciplines, but they also present significant challenges. As both wildfire and nonnative plant species elicit emotionally charged reactions, researchers are challenged to provide quantitative information to replace current opinions and dogma based on emotion and conjecture. The conventional wisdom is that many notorious nonnative plant species will dramatically increase and change future fire frequency following wildfire. A surprising number of papers draw conclusions about nonnative plant species and wildfire using this conventional wisdom as the null hypothesis, rather than using the more traditional and testable null hypothesis that the abundance of nonnative plants is not altered by wildfire.