bluuebunny/crossref_metadata_2025_split huggingface dataset:
Home away from home — objective mapping of high‐risk source areas for plant introductions
Authors: Richardson David M. , Thuiller Wilfried 
Published: February 2009

ABSTRACTPrevention is the best way to slow the escalation of problems associated with biological invasions. Screening of potential introductions is widely applied for assessing the risk of species becoming invasive. Despite advances in the understanding of the determinants of invasiveness, screening still relies heavily on assessments of the potential of species to ‘fit in’ to the broad environmental conditions of a target region. Most screening systems ask whether species are native to, or are known to be naturalized or invasive in, regions with ‘similar’ climatic/environmental conditions to the target region. The level of similarity required to make the species a high‐risk introduction is generally not specified. This paper describes a protocol for making such assessments more objective, using South Africa as a test case.Using nonparametric niche‐based modelling (generalized additive model; GAM) calibrated on the current distribution of each South African biome, we mapped regions of the world that are climatically similar to South African biomes. Lists were produced of countries with the largest areas climatically similar to South Africa overall, and to each biome separately. Validation of the usefulness of the approach was sought by evaluating whether the main invasive plant species in South African biomes occur naturally, or have adventive ranges, in regions mapped as analogous to South African biomes.A very large part of the world is climatically similar to South Africa, with eight countries having larger areas of land classified as climatically similar to South African biomes than the total area of South Africa. Almost all the most prominent invasive species in South African biomes occur naturally or are invasive outside their natural range in areas with similar climates to those that occur in parts of South Africa. This confirms the value of objective climate matching in screening protocols.We examined climatic conditions for a representative sample of major invasive plants from other parts of the world. The analysis identified several species that are already invasive in regions that have matched climates in South Africa but that are not yet introduced or, if already present, have not yet invaded large areas. For example, the following known invasive species should be considered high‐risk species in South African grasslands: Alliaria petiolata, Cytisus scoparius, Gleditsia triacanthos, Heracleum mantegazzianum, Hieracium pilosella, Juniperus communis, Pinus contorta, P. monticola, P. ponderosa, P. sylvestris, Prunus laurcerasus, and P. serotina. Objectively matched climatic regions are also useful as a first‐cut assessment when evaluating species with no invasive history.
An integrated framework to map animal distributions in large and remote regions
Authors: Travaini Alejandro , Bustamante Javier , Rodríguez Alejandro , Zapata Sonia , Procopio Diego , Pedrana Julieta , Martínez Peck Rolando 
Published: February 2009

ABSTRACTIn this paper we show how new technologies can be incorporated from the gathering of field data on wildlife distribution to the final stage of producing distribution maps. We describe an integrated framework for conducting wildlife censuses to obtain data to build predictive models of species distribution that when integrated in a GIS will produce a distribution map. Field data can be obtained with greater accuracy and at lower costs using a combination of Global Positioning System, Personal Digital Assistant, and specific wildlife recording software. Sampling design benefits from previous knowledge of environmental variability that can be obtained from free remote sensing data. Environmental predictors derived from this remote sensing information alone, combined with automatic procedures for predictor selection and model fitting, can render cost‐effective predictive distribution models for wildlife. We show an example with guanaco distribution in the Patagonian steppes of Santa Cruz province, Argentina.
Predicting species distributions from museum and herbarium records using multiresponse models fitted with multivariate adaptive regression splines
Authors: Elith Jane , Leathwick John 
Published: February 2009

ABSTRACTCurrent circumstances — that the majority of species distribution records exist as presence‐only data (e.g. from museums and herbaria), and that there is an established need for predictions of species distributions — mean that scientists and conservation managers seek to develop robust methods for using these data. Such methods must, in particular, accommodate the difficulties caused by lack of reliable information about sites where species are absent. Here we test two approaches for overcoming these difficulties, analysing a range of data sets using the technique of multivariate adaptive regression splines (MARS). MARS is closely related to regression techniques such as generalized additive models (GAMs) that are commonly and successfully used in modelling species distributions, but has particular advantages in its analytical speed and the ease of transfer of analysis results to other computational environments such as a Geographic Information System. MARS also has the advantage that it can model multiple responses, meaning that it can combine information from a set of species to determine the dominant environmental drivers of variation in species composition. We use data from 226 species from six regions of the world, and demonstrate the use of MARS for distribution modelling using presence‐only data. We test whether (1) the type of data used to represent absence or background and (2) the signal from multiple species affect predictive performance, by evaluating predictions at completely independent sites where genuine presence–absence data were recorded. Models developed with absences inferred from the total set of presence‐only sites for a biological group, and using simultaneous analysis of multiple species to inform the choice of predictor variables, performed better than models in which species were analysed singly, or in which pseudo‐absences were drawn randomly from the study area. The methods are fast, relatively simple to understand, and useful for situations where data are limited. A tutorial is included.
Using generalized dissimilarity modelling to analyse and predict patterns of beta diversity in regional biodiversity assessment
Authors: Ferrier Simon , Manion Glenn , Elith Jane , Richardson Karen 
Published: February 2009

ABSTRACTGeneralized dissimilarity modelling (GDM) is a statistical technique for analysing and predicting spatial patterns of turnover in community composition (beta diversity) across large regions. The approach is an extension of matrix regression, designed specifically to accommodate two types of nonlinearity commonly encountered in large‐scaled ecological data sets: (1) the curvilinear relationship between increasing ecological distance, and observed compositional dissimilarity, between sites; and (2) the variation in the rate of compositional turnover at different positions along environmental gradients. GDM can be further adapted to accommodate special types of biological and environmental data including, for example, information on phylogenetic relationships between species and information on barriers to dispersal between geographical locations. The approach can be applied to a wide range of assessment activities including visualization of spatial patterns in community composition, constrained environmental classification, distributional modelling of species or community types, survey gap analysis, conservation assessment, and climate‐change impact assessment.
Non‐stationarity and local approaches to modelling the distributions of wildlife
Authors: Osborne Patrick E. , Foody Giles M. , Suárez‐Seoane Susana 
Published: February 2009

ABSTRACTDespite a growing interest in species distribution modelling, relatively little attention has been paid to spatial autocorrelation and non‐stationarity. Both spatial autocorrelation (the tendency for adjacent locations to be more similar than distant ones) and non‐stationarity (the variation in modelled relationships over space) are likely to be common properties of ecological systems. This paper focuses on non‐stationarity and uses two local techniques, geographically weighted regression (GWR) and varying coefficient modelling (VCM), to assess its impact on model predictions. We extend two published studies, one on the presence–absence of calandra larks in Spain and the other on bird species richness in Britain, to compare GWR and VCM with the more usual global generalized linear modelling (GLM) and generalized additive modelling (GAM). For the calandra lark data, GWR and VCM produced better‐fitting models than GLM or GAM. VCM in particular gave significantly reduced spatial autocorrelation in the model residuals. GWR showed that individual predictors became stationary at different spatial scales, indicating that distributions are influenced by ecological processes operating over multiple scales. VCM was able to predict occurrence accurately on independent data from the same geographical area as the training data but not beyond, whereas the GAM produced good results on all areas. Individual predictions from the local methods often differed substantially from the global models. For the species richness data, VCM and GWR produced far better predictions than ordinary regression. Our analyses suggest that modellers interpolating data to produce maps for practical actions (e.g. conservation) should consider local methods, whereas they should not be used for extrapolation to new areas. We argue that local methods are complementary to global methods, revealing details of habitat associations and data properties which global methods average out and miss.
Large‐scale plant conservation in European semi‐natural grasslands: a population genetic perspective
Authors: Picó F. Xavier , Van Groenendael Jan 
Published: February 2009

ABSTRACTDuring the last century, unprecedented landscape fragmentation has severely affected many plant species occurring in once widespread semi‐natural grasslands in Europe. Fragmentation reduces population size and increases isolation, which can jeopardize the persistence of populations. Recent large‐scale ecological and genetic studies across several European countries indicate that fragmented populations of common plant species exhibit a strong genetic differentiation and local adaptation to their home sites, reducing their capacity to establish new populations elsewhere. We discuss the main genetic processes that determine the performance of plant populations in severely fragmented landscapes: namely inbreeding depression, genetic differentiation and genetic introgression. We stress the need for large‐scale genetic studies to detect the geographical structure of genetic variation of fragmented plant populations, since nuclei of genetically independent groups of populations may become important targets of conservation. A thorough knowledge on the large‐scale geographical structure of genetic variation for a sufficiently wide array of plant species can provide the basis to develop comprehensive conservation plans to preserve the ecological and evolutionary processes that generate and maintain biodiversity of fragmented semi‐natural grasslands.
Contrasting fire‐related resilience of ecologically dominant ants in tropical savannas of northern Australia
Authors: Andersen Alan N. , Parr Catherine L. , Lowe Lyn M. , Müller Warren J. 
Published: February 2009

ABSTRACTThis paper examines the role of fire in mediating the relative abundance of two of the world's major ecologically dominant ant genera, Iridomyrmex and Oecophylla, where they coexist across the tropical savanna landscapes of northern Australia. These taxa have contrasting biogeographical histories, which are predicted to lead to contrasting responses to fire. Iridomyrmex is an autochthonous Australian genus that has radiated primarily in the arid zone; as such, its abundance is predicted to be promoted by frequent fire because this maintains an open habitat. In contrast, Oecophylla is a genus of leaf‐nesting ants occurring in the canopies of Old World tropical rainforest, and is a recent arrival to Australia in geological time; the abundance of these ants is predicted to decline under frequent fire. We test these predictions using results from a landscape‐scale fire experiment, where three experimental fire regimes (including no fire) were applied to replicated subcatchments over a 5‐year period. Using sweep nets, ants were sampled in the grass layer (the habitat layer of greatest overlap between Iridomyrmex and Oecophylla) in eucalypt woodland (canopy cover < 30%) and open eucalypt forest (canopy cover about 50%) habitats. A total of 27 species from 11 genera were collected during the study; eight were common enough for statistical analysis, and the abundances of four of these were significantly affected by fire treatment. As predicted, the abundance of Iridomyrmex was promoted by fire, whereas that of Oecophylla declined. These changes occurred only under late‐season (relatively high intensity) fires, and for Oecophylla occurred only in open forest (not woodland) habitat. This fire‐mediated relationship between Iridomyrmex and Oecophylla mirrors the much broader, ecosystem‐wide dynamic between eucalypt‐dominated savanna and rainforest in tropical Australia, with savannas dominated by fire‐resistant sclerophyll elements of Australian origin, and rainforest dominated by fire‐sensitive mesophyll elements of South‐East Asian origin.
Inferring historical introduction pathways with mitochondrial DNA: the case of introduced Argentine ants (Linepithema humile) into New Zealand
Authors: Corin Steve E. , Lester Phillip J. , Abbott Kirsti L. , Ritchie Peter A. 
Published: February 2009

ABSTRACTThe threat imposed by invasive species and difficulties associated with control and management places more impetus on trying to prevent their introduction. The identification of introduction pathways is a vital component towards this goal. In this study, we use a genetic marker‐based approach to retrospectively investigate the pathway of origin of the invasive Argentine ant (Linepithema humile) into New Zealand. We intensively sample the mitochondrial gene cytochrome b, from the entire known range of Argentine ants in New Zealand. No genetic variation was found in New Zealand. In order to identify likely introduction pathways, we use two alternative genetic analyses and suggest that a tcs approach that collapses identical haplotypes and calculates the probability of parsimony is superior to standard phylogenetic tree‐building algorithms. A minimum spanning network allowed relationships to be examined among sequences collated from previous international studies. The cytochrome b sequence, when compared to a global database, matched that from an Australian population. That Australia is the potential source of Argentine ants is in agreement with the New Zealand interception record, as goods from Australia have the highest number of interception records of Argentine ants. Our approach can easily be duplicated for other organisms and the methodology can be more widely applied to help aid further efforts to identify the routes of transmission for other invasive species and allow us to efficiently direct our biosecurity monitoring effort.
Patterns of non‐randomness in the exotic avifauna of Florida
Authors: Blackburn Tim M. , Cassey Phillip 
Published: February 2009

ABSTRACTIt is now generally recognized that human‐mediated biological invasion is a multistage process, successively comprising transport, introduction, establishment, and spread, and that a complete understanding of the causes of invasion requires studies of all stages. However, while many studies address the characteristics that influence establishment, relatively few address the characteristics that influence whether or not a species transits the earlier stages of transport and introduction. Here, we use data on the rich exotic avifauna of Florida to assess non‐randomness in the identities of species that have passed through the transport and introduction stages. Bird species transported and introduced to Florida are non‐random with respect to their taxonomic affiliations, body mass, native geographical range size, and region of origin: introductions are more likely for widespread, large‐bodied species from the Neotropics and belonging to the Anatidae, Psittacidae, Ciconiidae, and Passeridae. Data on the identities of species that have attempted to breed but failed, and on the breeding population size for most established species, also allowed us to assess the extent to which the same variables influenced various aspects of post‐introduction establishment. Only native geographical range size and latitudinal range mid‐point distinguish between these different classes of exotic species. Geographical range size is the most general correlate of different classes of invaders in our analyses.
A century of the ornamental plant trade and its impact on invasion success
Authors: Dehnen‐Schmutz Katharina , Touza Julia , Perrings Charles , Williamson Mark 
Published: February 2009

ABSTRACTWe identify a significant relationship between domestic market‐based propagule pressure, as measured both in presence in the British horticultural market and in seed prices of ornamental plant species, with success in invasion. We employ a multispecies temporal approach and use a Generalized Estimation Equation model comparing ornamental non‐native species introduced into Britain which started to invade with species introduced but not known outside cultivation. Historical nursery catalogues gave information on the availability and prices of seeds of 506 ornamental species in the British horticultural market every 20 years from 1885 to 1985. Higher market frequency and cheap prices of seeds were more significant and had a greater impact on the invading probability 20 years later than at the date of listing in a nursery catalogue. Our results suggest that national economic factors are an important part of the explanation for the invasiveness of ornamental plant species, and hence for the development of potential solutions.
Algal communities in human‐impacted stream ecosystems suffer beta‐diversity decline
Authors: Passy Sophia I. , Blanchet F. Guillaume 
Published: February 2009

ABSTRACTHuman‐mediated geomorphic degradation of streams and rivers is a serious environmental problem with negative effects on aquatic biota and social infrastructure. Billions of dollars are spent for stream restoration in the USA alone, but it is still unknown how algal diversity is affected by these efforts. In this investigation, we studied a geomorphically stable and heterogeneous reach and two degraded and homogeneous reaches of Batavia Kill, a highland stream in New York, USA. Spatial surveys of algae and geomorphic conditions were conducted in all three reaches for 2 years. After the first year of study, one of the two unstable reaches was subjected to a large‐scale streambed restoration. Species–area relationships (SAR) were examined for the first time in local algal communities of stream periphyton. Alpha‐ and gamma‐diversity, which represent the species richness at a sample and reach level, respectively, and cell density, were also explored. In all reaches, SAR were fitted with semi‐log models, which revealed that the rate of increase of species richness with area, i.e. algal beta‐diversity, was significantly higher in the geomorphically stable reach than in the two degraded reaches. Gamma‐diversity followed the same trend, whereas alpha‐diversity and cell density were significantly higher in the unstable reaches. Restoration significantly increased the heterogeneity of conditions, including depth and particle size. From all studied community descriptors, restoration had a benign influence on algal beta‐ and gamma‐diversity; however, beta‐diversity remained the highest in the stable reference reach and this difference was significant. Our results provide guidelines for the use of periphytic algae in future bioassessments of stream bank restoration. Community properties such as species richness and organismal density, which are common metrics of ecosystem health, may be inappropriate in stream restoration surveys; instead diversity measures, often overlooked in applied ecology, e.g. beta‐diversity, should be given full consideration.
A global gap analysis of infectious agents in wild primates
Authors: Hopkins Mariah E. , Nunn Charles L. 
Published: February 2009

ABSTRACTA number of infectious diseases have emerged as threats to humans and wildlife. Despite the growing importance of georeferenced data for mitigating disease risk, information on parasite threat is patchily distributed at a global scale. In this paper, we explore the utility of gap analysis techniques to investigate the global geographical distribution of parasite sampling in non‐human primates. Specifically, we identify geographical areas that are undersampled for parasites in relation to primate geographical distributions, primate taxonomic sampling, primate threat status, and parasite taxonomy. Our results reveal that East Asia (particularly China), South‐East Asia, and the South American Amazon are the most deficient in sampling effort with respect to all criteria. We also identify sampling gaps based on several criteria in West and Central Africa. Future research aimed at filling these gaps is needed for both human health and primate conservation purposes.
Classification, diversity, and distribution of Chilean Asteraceae: implications for biogeography and conservation
Authors: Moreira‐Muñoz Andrés , Muñoz‐Schick Mélica 
Published: February 2009

ABSTRACTThis paper provides a synopsis of the Chilean Asteraceae genera according to the most recent classification. Asteraceae is the richest family within the native Chilean flora, with a total of 121 genera and c. 863 species, currently classified in 18 tribes. The genera are distributed along the whole latitudinal gradient in Chile, with a centre of richness at 33°–34° S. Almost one‐third of the genera show small to medium‐small ranges of distribution, while two‐thirds have medium‐large to large latitudinal ranges of distribution. Of the 115 mainland genera, 46% have their main distribution in the central Mediterranean zone between 27°–37° S. Also of the mainland genera, 53% occupy both coastal and Andean environments, while 33% can be considered as strictly Andean and 20% as strictly coastal genera. The biogeographical analysis of relationships allows the distinction of several floristic elements and generalized tracks: the most marked floristic element is the Neotropical, followed by the antitropical and the endemic element. The biogeographical analysis provides important insights into the origin and evolution of the Chilean Asteraceae flora. The presence of many localized and endemic taxa has direct conservation implications.