bluuebunny/crossref_metadata_2025_split huggingface dataset:
GIS interpolations of witness tree records (1839–1866) for northern Wisconsin at multiple scales
Authors: He Hong S. , Mladenoff David J. , Sickley Theodore A. , Guntenspergen Glenn G. 
Published: March 2003

AbstractTo construct forest landscape of pre‐European settlement periods, we developed a GIS interpolation approach to convert witness tree records of the U.S. General Land Office (GLO) survey from point to polygon data, which better described continuously distributed vegetation. The witness tree records (1839–1866) were processed for a 3‐million ha landscape in northern Wisconsin, U.S.A. at different scales. We provided implications of processing results at each scale. Compared with traditional GLO mapping that has fixed mapping scales and generalized classifications, our approach allows presettlement forest landscapes to be analysed at the individual species level and reconstructed under various classifications. We calculated vegetation indices including relative density, dominance, and importance value for each species, and quantitatively described the possible outcomes when GLO records are analysed at three different scales (resolution). The 1 × 1‐section resolution preserved spatial information but derived the most conservative estimates of species distributions measured in percentage area, which increased at coarser resolutions. Such increases under the 2 × 2‐section resolution were in the order of three to four times for the least common species, two to three times for the medium to most common species, and one to two times for the most common or highly contagious species. We mapped the distributions of hemlock and sugar maple from the pre‐European settlement period based on their witness tree locations and reconstructed presettlement forest landscapes based on species importance values derived for all species. The results provide a unique basis to further study land cover changes occurring after European settlement.
Evolutionary biogeography and speciation: essay on a synthesis
Authors: Salomon Marc 
Published: March 2003

AimDifferent continental and insular speciation processes are reviewed. The areal and clinal conceptions of speciation studies are discussed. I propose a revisited cline theory reconciling cline mechanics and allopatric speciation as cline analysis allows quantification in speciation description more easily and integrates polymorphism within speciation processes. In addition, insular speciation illustrates what could have been the first allopatric stages of many current continental speciations. Intrinsic correspondence is shown between areal and clinal conceptions, and between continental and insular speciation processes; this article is thus an essay towards a unified theory of speciation biogeography.
Effects of habitat fragmentation on carabids in forest patches
Authors: Magura Tibor , Ködöböcz Viktor , Tóthmérész Béla 
Published: March 2003

AimThe aim of this study was to test some of the classical rules of island biogeography for the carabid beetles (Coleoptera: Carabidae) in 15 forest patches during 1995–99.LocationThe 15 forest patches studied are located on the Bereg Plain. The Bereg Plain is at the foot of the Carpathians, partly in Hungary and partly in the Ukraine. Even in recent times, the area was covered by continuous woodland of deciduous trees, and the species of the closed canopy deciduous forest of the hills and mountains were able to disperse from the Carpathians to these lowland forests. But now, because of agricultural activities and forest management, this woodland is fragmented into forest patches.MethodsThe species–area and the number of species–distance to mainland relationships, and the influence of other factors like shape, isolation, and altitude above the see level, on the number of species were studied. We have used three categories of species during the analyses: (i) total number of species; (ii) the number of species of the closed canopy deciduous forest of the hills and mountains (ForHim species); and (iii) the number of widely distributed generalist species (WidGe species).ResultsThere were positive, but statistically insignificant correlations between the distance to the Carpathians and the total number of species, and also between the distance to the Carpathians and the number of WidGe species. The correlation was negative for the number of ForHim species, and it was also not significant. There were significant negative correlation between both the total number of species and the number of WidGe species and the size of the forest patches, while there were significant positive correlation between the size of forest patch and the number of ForHim species. The number of ForHim species decreased significantly by the increase of isolation, while the number of WidGe species increased by the isolation. Shape of the forest patches, and their altitude above the sea level had no influence on the total species richness, the ForHim species richness, and the WidGe species richness. We have also proved that each of the total species richness, the ForHim species richness, and the WidGe species richness, is higher for many small forest patches than for one large patch of the same total area.Main conclusionsOur results suggest that historical reasons have a vital influence on the present species patterns. Moreover, in biogeographical studies we must distinguish between species which recognize the habitat as a patch or island and those that can survive in the neighbouring habitats as well. An ignorance of these two categories may disguise basic biogeographic rules.
Latitudinal gradients and geographic ranges of exotic species: implications for biogeography
Authors: Sax D.F. 
Published: March 2003

AimTo explore the biogeographic patterns of exotic species in order to discriminate between hypotheses postulated to produce several biogeographic phenomena: the latitudinal gradient in species richness, the latitudinal gradient in species geographical range size (Rapoport’s rule), species geographical range boundaries and patterns of invasion in the tropics.LocationData were taken from North and South America, Europe, Asia, Africa and oceanic islands.MethodsThe latitudinal extents of the geographical range of exotic species were recorded to the nearest 1° of latitude from several published sources. Species richness was tabulated by recording the number of naturalized species present within 5° bands of latitude. Rapoport’s rule was calculated by averaging the latitudinal extent of all exotic species present within 5° bands. The low‐latitude boundaries of species’ native and naturalized ranges were compared with the nearest 1° of latitude. These comparisons on continents were contrasted with those on islands.ResultsWithin the tropics, few exotic species have become naturalized and those that are have established large geographical ranges. Outside of the tropics, exotic species of birds, mammals, fishes and plants demonstrate qualitatively similar latitudinal gradients in richness and geographical range size. They show the same patterns as native species, where richness is negatively correlated and range size positively correlated with latitude. Further, the geographical ranges of naturalized species on continents rarely extend to latitudes lower than those in their native ranges. On islands (where biotic pressure is reduced) exotic species are more frequently naturalized at latitudes lower than those in their native ranges.Main conclusionsHypotheses for the latitudinal gradient in species richness and geographical range size that are based on past glaciation events or differential rates of speciation between regions may not be necessary to explain these gradients, as exotic species are recent colonists and their patterns of distribution cannot have been directly affected by past glaciation events or differential rates of speciation between regions. Further, the low‐latitude boundary of species geographical ranges may be set by tolerance for biotic pressure.
Historical biogeography and Late Quaternary environmental change of Lake Pamvotis, Ioannina (north‐western Greece): evidence from ostracods
Authors: Frogley Michael R. , Griffiths Huw I. , Heaton Timothy H. E. 
Published: March 2003

AimThe purpose of this study is to (1) investigate the Quaternary history of Lake Pamvotis using fossil ostracod faunal and isotopic analyses, and (2) use this fossil evidence to assess the pedigree of the lake's fauna and place it within a regional palaeobiogeographical context.LocationLake Pamvotis, situated in the Ioannina Basin, north‐western Greece.MethodsFossil samples were recovered from a 319 m‐long, 500 ka core drilled on the eastern shore of the current lake. Stable isotopic analyses were carried out on ostracod shell calcite.ResultsA total of 17 ostracod taxa were recovered, of which 13 occur in the modern lake. Fossil assemblages and corresponding isotopic profiles from the Last (Eemian) Interglacial and Last Glacial‐Holocene transition are presented and compared with modern‐day data. Some taxa (e.g. Leptocythere sp. A) appear to be lake basin endemics.Main conclusionsThe ostracod fauna is typical of temperate, carbonate‐rich standing waters and includes both European and Balkan endemic elements. The fossil fauna, coupled with the isotopic data, provides evidence for past lake‐level change, including a progressive deepening throughout much of the Last Interglacial and a gradual shallowing throughout the subsequent glacial. This culminated in a distinct interval of low lake‐levels at the height of the last glaciation. The Lateglacial witnessed a partial recovery in lake depth, although shallowing occurred once again during the Holocene. The biogeographical affinities of the ostracod fauna, whilst not unequivocal, nevertheless suggest that speciation in the region has been by vicariance and hydrological isolation, probably within the Pleistocene.
The effect of tropical deforestation on stingless bees of the genus Melipona (Insecta: Hymenoptera: Apidae: Meliponini) in central Rondonia, Brazil
Authors: Brown J. Christopher , Albrecht Christian 
Published: March 2003

Aim(1) To determine whether deforestation has affected the incidence of species of Melipona in an area undergoing deforestation. (2) To highlight the potential use of GIS and remote‐sensed environmental variables in studies of insects as bioindicators of landscape change.LocationCentral Rondonia, Brazil in the south‐western Amazon Basin, an area under intense deforestation pressure for agriculture and cattle ranching since the 1970s.MethodsStingless bees of the genus Melipona were sampled outside of forest cover on iron‐weed, Vernonia polynthes Less., at 69 locations along a deforestation gradient within a 3150‐km2 study area. We related species richness and composition for each sample point to local and regional deforestation variables, including geographical position along the deforestation gradient, distance to the forest, and percentage of primary forest coverage within a 1 and 2 km radius of the sample points. Deforestation variables were generated using GIS and LANDSAT TM imagery of the study area. Redundancy analysis was used to illustrate the relationship between species incidence, the deforestation variables, and other possible confounding environmental variables.ResultsSeven species were found within the study area. Two species (M. seminigra abunensis Cockerell, 1912 and M. grandis Guérin, 1844) appear not to be affected by deforestation yet, occurring evenly across the deforestation gradient. Two other common species (M. melanoventer Schwarz, 1932 and M. rufiventris brachychaeta Moure, 1950), however, occurred mainly towards the end of the gradient where the forest was more intact, indicating relative susceptibility to deforestation. Melipona species richness, ranging from 1 to 5 species, was inversely related to distance to forest and directly related to percentage of forest cover.Main conclusionsAdverse effects of deforestation on Melipona are detectable in the study area, despite the fact that significant areas of tropical forest cover remain. The species that are most affected may be considered indicators of landscape change, and efforts to protect these species could involve their use in beekeeping programmes designed to raise rural incomes and maintain regional biodiversity.
Birds of paradise, biogeography and ecology in New Guinea: a review
Authors: Heads Michael 
Published: March 2003

AimThe paper reviews the biogeography and ecology of New Guinea using the birds of paradise (Paradisaeidae) as an illustrative example.LocationNew Guinea, the Moluccas, North‐eastern Australia.MethodsPanbiogeographic analysis (Crawet al., 1999).ResultsThe family Paradisaeidae is interpreted as the main New Guinea vicariant inSibley & Ahlquist’s (1990)Corvinae. It has evolved mainly on the New Guinea orogen, extending, like the orogen, to the northern Moluccas and the Milne Bay islands, but not present north of it on Karkar Island or New Britain. Within the orogen, Vogelkop – Huon Peninsula disjunctions (1500 km) occur between putative sister species inParadisaea,AstrapiaandParotia. Whatever taxonomic rank these affinities warrant, the biogeographic connection is inexplicable by ‘jump’ dispersal from the mainland, but is compatible with an accreted terrane model of New Guinea tectonics including massive lateral strike‐slip movement. This would also account for many aspects of distribution of Paradisaeidae within the New Guinea highlands, and also disjunctions between Sulawesi and the Bismarck Archipelago in the related genusArtamus.Main conclusionsBirds of paradise are sedentary forest dwellers with small home ranges and are tolerant of disturbance. It is suggested that populations have been caught in the dramatic geological uplift and downwarping of different parts of New Guinea. This has led to fragmentation and juxtaposition of ranges, and determined the altitudinal range of the taxa (including altitudinal ‘anomalies’). Areas of endemism in birds of paradise include Quaternary volcanoes. In New Guinea large areas have eventually been covered by lava flows of different volcanic phases, but the living communities, including local endemics, may remain more or lessin situby constantly colonizing younger flows from adjacent older flows. In this way older life can ‘float’ on younger stratigraphy. At least five, possibly six, of the fifteen genera in subfam. Paradisaeinae are known to occur in mangrove. The ancestors of Paradisaeidae and other New Guinea bird families such as Ptilonorhynchidae probably included birds of the mangrove, beach forest and coastal hinterland which have been stranded in central Australia following marine transgressions (Ptilonorhynchidae) and uplifted in New Guinea during the Tertiary orogeny (Ptilonorhynchidae and Paradisaeidae).
Grasshopper (Orthoptera: Acridoidea) and plant community relationships in the Argentine pampas
Authors: Torrusio Sandra , Cigliano María M. , De Wysiecki María L. 
Published: March 2003

AimThe objectives of this study were to relate species density, richness and relative abundance of grasshoppers to habitat vegetation and to detect variations in these variables among native and exotic plant communities which reflected disturbance history.LocationTwenty‐seven sites were selected in 2000 representing a variety of native and exotic plant communities, with different degrees of disturbance history, in south‐east Buenos Aires province, Argentina.MethodsGrasshopper mean density, species relative abundance and species composition were estimated at each site via standard flushing and sweep net techniques. Plant associations at each site were estimated by evaluating the percentage canopy of ground cover of native perennial grasses, introduced perennial forbs, annual pastures, halophilous species, perennial pastures, native perennial forbs, introduced annual forbs and plant species richness. Based on vegetation variables, sites were classified into five disturbance categories: native grasslands, halophilous grasslands, pastures, moderately disturbed pastures and highly disturbed pastures.ResultsGrasshopper communities from sites dominated by introduced plant species (forbs, sown grasses and dicots), were characterized by relatively high densities and a high proportion of potential pest species. Native grassland sites showed lower grasshopper densities, while halophilous grassland had high densities, but with low proportion of potential pest species.Main conclusionsResults from this study suggest that the most abundant and economic important species of the pampas, Dichroplus elongatus, was associated with sown pasture plants (grasses and dicots) and introduced forbs, and negatively correlated with natural communities (native vegetation and halophilous species). These relationships imply that appropriate management practices that leave more areas with natural vegetation and include perennial pastures and native species in the rotations could show beneficial in reducing the overall density and the proportion of the primary pest species in south‐eastern Buenos Aires province.
Endemic mammalian genera: are they really unique?
Authors: Danell Kjell , Aava‐Olsson Birgitta 
Published: March 2003

AimThe majority (64%) of the extant 1153 mammalian genera occupy only one zoogeographical region and can in that sense be referred to as endemic to that region. The aim in this study was to find out if endemic genera differ in ecological characteristics, e.g. taxonomy, body size, feeding and substrate use, from genera with a more cosmopolitan distribution, and if endemic genera were distributed along a productivity gradient.LocationThe sixteen major zoogeographical regions of the world, including continents, islands and oceans.MethodsWe grouped the mammal genera according to their distribution in endemic (one region) and cosmopolitan (4–12 regions), respectively. Further, we divided the eleven major terrestrial regions of the world into continental and island regions and examined the effect of productivity on the number of endemic genera.ResultsWe found statistically significant differences in order, body mass, feeding habit and substrate utilization between the two mammal groups. The endemic genera was dominated by the order Rodentia and were mainly small‐sized, insectivore, frugivore/omnivore or herbivore, semifossorial, terrestrial or arboreal. The small fraction (5%) of genera with the widest distribution (4–12 regions) belonged mainly to the orders Chiroptera, Cetacea and Carnivora and were either small‐ or large‐sized, piscivore/squid‐eater or insectivore, aquatic, terrestrial or volant. We found only weak relationships with productivity for both sets of regions with a positive slope for continental regions and a negative one for island regions. As all island regions were more productive than continental regions, endemic genera were most common in intermediately productive regions overall.Main conclusionsWe conclude that there are major ecological differences between endemic and cosmopolitan genera of mammals.
Realized and potential climate niches: a comparison of four Rhododendron tree species
Authors: Vetaas Ole R. 
Published: March 2003

AimThis study aims to evaluate the hypothesis that there is no difference between the realized and the ex‐situ niches of four selected Rhododendron tree species. If the hypothesis is rejected, the aim is: (1) to evaluate whether the magnitude of discrepancy between the two types of niche is related to competition or external constraint, and (2) to identify which niche dimension is expanded (cold and/or warm limits) and to discuss it in relation to the assumption behind the biogeographical projections related to global warming.LocationThe four target species (Rhododendron arboreum Sm., R. campanulatum D. Don, R. barbatum Wall., and R. wallichi Sm.) are common evergreen broad‐leaved trees in the central Himalayas. Their realized niches are based on data from the elevation‐temperature gradient in Nepal (1000–5000 m a.s.l.). The ex‐situ data are from botanical gardens and arboreta mainly located in the northern hemisphere (n=43).MethodsBinary data on these taxa were obtained from 707 geocoded herbarium specimens (elevation and UTM location) and from two elevation transects in Nepal (n=194 plots). Climate conditions from ex‐situ locations for each taxon were compared with their realized climate ranges with respect to (i) mean annual temperature (MAT), (ii) mean minimum temperature of the coldest month (MINCM), (iii) mean maximum temperature of the warmest month (MAXWM), and (iv) moisture index (MI). Realized optima were estimated by Generalized Linear Models (GLM), and its non‐parametric extension, Generalized Additive Models (GAM), were used to estimate the realized niches.ResultsAll target species have ex‐situ individuals outside the realized climate niche, but the number is much higher for maximum and minimum variables than for MAT. The most dominant species (in‐situ), R. arboreum, had very few individuals outside its realized range, indicating congruence between its ex‐situ and realized niches. The other taxa had many individuals outside the warm end of their realized temperature ranges, but almost none beyond the cold end of their ranges. All target taxa occur in common gardens under warm temperate conditions, but only R. arboreum grows in the warm temperate zone in the Himalayas. This trend at the warm end of the gradient is interpreted as a result of biotic exclusion.Main conclusionThe results demonstrate that an extreme cold temperature may represent an absolute boundary for tree species' survival, whereas warm temperatures do not. This is in agreement with the hypothesis that several tree species may survive global warming in‐situ because of high temperature tolerance, but its effect on regeneration is uncertain. In lieu of this there may be a significant time lag between change in climate and transient tree species distribution. Thus the effect of global warming on tree species distribution may be very difficult to predict.