bluuebunny/crossref_metadata_2025_split huggingface dataset:
Extinction and replacement in the Indo‐West Pacific Ocean
Authors: Briggs John C. 
Published: March 2003

Summary Aim To provide evidence suggesting the existence of a dynamic system of extinction and replacement. Location The Indo‐West Pacific Ocean. Methods Utilization of species distribution patterns produced by detailed systematic works. Results The distribution patterns appear to suggest a sequence of events that is consistent with the centre of origin hypothesis. The East Indies centre is considered to operate according to the centrifugal speciation model. Main conclusions Disjunct patterns appear to have originated in the East Indies and spread out from there. In cases where the vacated area is occupied by a sibling species, competitive (sympatric) speciation may have occurred. Over time the extinction pattern will gradually extend outward until it is played out among small populations far from their centre of origin
The Holdridge life zones of the conterminous United States in relation to ecosystem mapping
Authors: Lugo A. E. , Brown S. L. , Dodson R. , Smith T. S. , Shugart H. H. 
Published: March 2003

Summary Aim Our main goals were to develop a map of the life zones for the conterminous United States, based on the Holdridge Life Zone system, as a tool for ecosystem mapping, and to compare the map of Holdridge life zones with other global vegetation classification and mapping efforts. Location The area of interest is the forty‐eight contiguous states of the United States. Methods We wrote a PERL program for determining life zones from climatic data and linked it to the image processing workbench (IPW). The inputs were annual precipitation (Pann), biotemperature (Tbio), sea‐level biotemperature (T0bio), and the frost line. The spatial resolution chosen for this study (2.5 arc‐minute for classification, 4‐km for mapping) was driven by the availability of current state‐of‐the‐art, accurate and reliable precipitation data. We used the Precipitation‐elevation Regressions on Independent Slopes Model, or PRISM, output for the contiguous United States downloaded from the Internet. The accepted standard data for air temperature surfaces were obtained from the Vegetation/Ecosystem Modelling and Analysis Project (VEMAP). This data set along with station data obtained from the National Climatic Data Center for the US, were used to develop all temperature surfaces at the same resolution as the Pann. Results The US contains thirty‐eight life zones (34% of the world's life zones and 85% of the temperate ones) including one boreal, twelve cool temperate, twenty warm temperate, four subtropical, and one tropical. Seventy‐four percent of the US falls in the ‘basal belt’, 18% is montane, 8% is subalpine, 1% is alpine, and < 0.1% is nival. The US ranges from superarid to superhumid, and the humid province is the largest (45% of the US). The most extensive life zone is the warm temperate moist forest, which covers 23% of the country. We compared the Holdridge life zone map with output from the BIOME model, Bailey's ecoregions, Küchler potential vegetation, and land cover, all aggregated to four cover classes. Despite differences in the goals and methods for all these classification systems, there was a very good to excellent agreement among them for forests but poor for grasslands, shrublands, and nonvegetated lands. Main conclusions We consider the life zone approach to have many strengths for ecosystem mapping because it is based on climatic driving factors of ecosystem processes and recognizes ecophysiological responses of plants; it is hierarchical and allows for the use of other mapping criteria at the association and successional levels of analysis; it can be expanded or contracted without losing functional continuity among levels of ecological complexity; it is a relatively simple system based on few empirical data; and it uses objective mapping criteria.
Simulating effects of climate change on boreal ecosystem carbon pools in central Canada
Authors: Price D. T. , Peng C. H. , Apps M. J. , Halliwell D. H. 
Published: March 2003

SummaryAimPossible effects of current and future climates on boreal vegetation dynamics and carbon (C) cycling were investigated using the CENTURY 4.0 soil process model and a modified version of the FORSKA2 forest patch model.LocationEleven climate station locations distributed along a transect across the boreal zone of central Canada.MethodsBoth models were driven by detrended long‐term monthly climate data. Using a climate change signal derived from the GISS general circulation model (GCM) 2×CO2equilibrium climate scenario, the output from the two models was then used to compare simulated current and possible future total ecosystem C storage at the climate station locations.ResultsAfter allowing for their different underlying structures, comparison of output from both models showed good agreement with local field data under current climate conditions. CENTURY 4.0 was able to reproduce spatial variation in soil and litter C densities satisfactorily but tended to overestimate biomass productivity. FORSKA2 reproduced aboveground biomass productivity and spatially averaged biomass densities relatively well. Under the GISS 2×CO2scenario, both models generally predicted small increases in aboveground biomass C density for forest and tundra locations, but CENTURY 4.0 predicted greater decreases in soil and litter pools, for overall decreases in ecosystem C storage in the range 16–19%.Main conclusionsWith some caveats, results imply that effects of increased precipitation (as simulated by the GISS GCM) would more than compensate for any negative effects of increased temperature on forest growth. Increased temperature would also increase decomposition rates of soil and litter organic matter, however, for a net overall decrease in total ecosystem C storage.
Forest area and distribution in the Mississippi alluvial valley: implications for breeding bird conservation
Authors: Twedt Daniel J. , Loesch Charles R. 
Published: March 2003

SummaryKnowing the current forest distribution and patch size characteristics is integral to the development of geographically defined, habitat‐based conservation objectives for breeding birds. Towards this end, we classified 2.6 million ha of forest cover within the Mississippi Alluvial Valley using 1992 thematic mapper satellite imagery. Although historically this area, from southern Illinois to southern Louisiana, was dominated by forested wetlands, forest cover remains on less than 25% of the floodplain. Remaining forest cover is comprised of > 38,000 discrete forest patches > 2 ha. Mean patch area (64.1±5.2 ha; x̄±SE) was highly skewed towards small fragment size. Larger patches had a higher proportion of more hydric forest cover classes than did smaller patches which had a higher proportion of less hydric forest cover classes. Public lands accounted for 16% of remaining forested wetlands. Fewer than 100 forest patches exceeded our hypothesized habitat objective (4000 ha minimum contiguous forest area) intended to support self‐sustaining populations of forest breeding birds. To increase the number of forest patches exceeding 4000 ha contiguous area, and thereby increase the likelihood of successful forest bird conservation, we recommend afforestation adjoining existing forest fragments ≥1012 ha and focused within designated Forest Bird Conservation Regions.
Biogeography of the Limacoidea sensu lato (Gastropoda: Stylommatophora): vicariance events and long‐distance dispersal
Authors: Hausdorf B. 
Published: March 2003

AbstractAim Reconstruction of the historical biogeography of the Limacoidea sensu lato (including the Staffordiidae, Dyakiidae, Gastrodontoidea, Parmacelloidea, Zonitidae, Helicarionoidea and Limacoidea). Evaluation of the relative importance of dispersal and its consequences.Location World‐wide.Methods Weighted ancestral area analysis.Results The ancestral areas of the individual clades have been delimited using weighted ancestral area analysis and a sequence of possible vicariance and dispersal events has been suggested. The results of the ancestral area analysis have tentatively been correlated with Cretaceous and Tertiary palaeogeography. The widely overlapping distribution patterns of several families of the Limacoidea testify to extensive dispersal events. Dispersal capacity of land snails is correlated with body size. The significant negative correlation between body size and distribution area size corroborates the importance of passive dispersal for the evolution of the distribution patterns.Main conclusions The existence of extensive dispersal events of poor active dispersers like land snails diminishes the importance of recent distribution patterns for the reconstruction of palaeogeography. On the other hand, dispersal ensures that biogeographical data reflect the geographical configurations at a given time and renders the use of palaeobiogeographic data for the reconstruction of palaeogeographic configurations of the respective age possible.
Upsides and downsides: contrasting topographic gradients in species richness and associated scenarios for climate change
Authors: Fleishman Erica , Fay John P. , Murphy Dennis D. 
Published: March 2003

AbstractAimWe tested whether montane butterflies exhibit similar responses to elevation in two adjacent mountain ranges in the Great Basin; whether surface water availability, canyon depth and canyon width vary predictably with elevation; and whether those factors act in conjunction with elevation to generate the observed gradients in species richness. These variables might reasonably be expected to affect species richness of butterflies and can be derived readily for most landscapes. We also explored how climate change may affect species distributions in both mountain ranges.LocationField research was conducted in the Toiyabe and Toquima ranges, Lander and Nye counties, Nevada, USA.MethodsWe obtained data for 102 locations in the Toiyabe Range and 49 locations in the Toquima Range. These locations covered an elevational gradient ofc.1350 m in the Toiyabe Range and 900 m in the Toquima Range. Species richness data were based upon comprehensive field inventories. Elevation was measured by differentially corrected global positioning systems. Values for the remaining predictive variables were derived using geographic information systems. Availability of surface water was quantified as the distance from the centre of the inventory route to the nearest permanent source of running or standing water.ResultsIn the Toiyabe Range, species richness decreases as elevation increases. Water availability and canyon depth and width vary predictably with elevation, but do not interact with elevation to affect species richness patterns. In the Toquima range, in contrast, species richness increases as elevation increases, and no other predictive variable covaries with elevation.Main conclusionsWe suggest that range‐specific gradients in climatic severity contribute to the distinct elevational gradients in species richness. In the face of climate change, species richness patterns in the Toquima range will likely remain similar. The elevational gradient in species richness in the Toiyabe range may flatten, or the patterns in the two ranges may converge.
Colonization success of carabid beetles on Baltic islands
Authors: Kotze D. Johan , Niemelä Jari , Nieminen Marko 
Published: March 2003

AbstractAims(1) To test whether there is a significant increase in carabid species richness with an increase in island size and, if so, if it is due to island areaper seor habitat diversity. (2) To investigate whether scattered islands accumulate species quicker than islands close to each other, per island size. (3) To investigate changes in the proportions of carabid wing morphs between the Finnish mainland and islands in the Baltic Sea.LocationIslands in the south‐western archipelago of Finland, in the Baltic Sea.MethodsCarabid beetles were collected using pitfall traps (diameter, 65 mm; volume, 170 mL), half‐filled with an ethylene‐glycol–water mixture, from 22 May to 20 September 1993 on 24 islands. Island size varied between 0.5 andc.7000 ha, and each island had between one and four habitat types sampled.ResultsA total of 61 carabid species were captured on these islands.Pterostichus nigerwas numerically dominant on 15 of the 24 islands and made up 34.5% of the total catch. The islands had a significantly higher proportion of brachypterous species compared to the Finnish mainland. The islands also accumulated species at a much slower rate (z = 0.06) than that generally observed in the literature, and, for carabids, a mainly predacious group, habitat diversity had little predictive power in explaining species richness. Islands close to each other (a few hundred metres apart) accumulated species at a slower rate than did scattered islands, as island size increased.Main conclusionsAlthough carabids disperse relatively easily to remote islands (perhaps a result of low Baltic Sea salinity and short interisland distances), colonization success appears to depend on a multitude of factors, including availability of suitable habitat on these islands, competitive superiority, survival ability during dispersal and island arrival sequence.
Are local patterns of anthropoid primate diversity related to patterns of diversity at a larger scale?
Authors: Lawes M. J. , Eeley H. A. C. 
Published: March 2003

AbstractAims  (1) To determine the relationship between local and regional anthropoid primate species richness. (2) To establish the spatial and temporal scale at which the ultimate processes influencing patterns of primate species coexistence operate.Location Continental landmasses of Africa, South America and Asia (India to China, and all islands as far south as New Guinea).Methods  The local–regional species richness relationship for anthropoid primates is estimated by regressing local richness against regional richness (independent variable). Local richness is estimated in small, replicate local assemblages sampled in regions that vary in total species richness. A strong linear relationship is taken as evidence that local assemblages are unsaturated and local richness results from proportional sampling of the regional pool. An asymptotic curvilinear relationship is interpreted to reflect saturated communities, where strong biotic interactions limit local richness and local processes structure the species assemblage. As a further test of the assumption of local assemblage saturation, we looked for density compensation in high‐density local primate assemblages.Results  The local–regional species richness relationship was linear for Africa and South America, and the slope of the relationship did not differ between the two continents. For Asia, curvilinearity best described the relationship between local and regional richness. Asian primate assemblages appear to be saturated and this is confirmed by density compensation among Asian primates. However, density compensation was also observed among African primates. The apparent assemblage saturation in Asia is not a species–area phenomenon related to the small size of the isolated islands and their forest blocks, since similar low local species richness occurs in large forests on mainland and/or peninsular Asia.Main conclusions In Africa and South America local primate assemblage composition appears to reflect the influence of biogeographic processes operating on regional spatial scales and historical time scales. In Asia the composition of primate assemblages are by‐and‐large subject to ecological constraint operating over a relatively small spatial and temporal scale. The possible local influence of the El Niño Southern Oscillations on the evolution and selection of life‐history characteristics among Asian primates, and in determining local patterns of primate species coexistence, warrants closer inspection.
Biogeographic relationships of the Galapagos terrestrial biota: parsimony analyses of endemicity based on reptiles, land birds andScalesialand plants
Authors: Bisconti  , Landini  , Bianucci  , Cantalamessa  , Carnevale  , Ragaini  , Valleri  
Published: March 2003

AimThe aim of this work is to provide a parsimony analysis of the Galapagos terrestrial vertebrates to understand their origin and relationships within the archipelago and to the American continents.LocationThe Galapagos archipelago is located 1000 km off the western coast of Ecuador. It is formed by 13 large islands (greater than 10 km2), six smaller islands and over 40 islets that have official names. Other small rocks and islets remain unnamed. The archipelago straddles the equator at the 90th meridian west.MethodsLists of the living reptilian, land bird species and genera andScalesialand plant species were compiled from various published and online works. Parsimony Analysis of Endemicity (PAE) was used to find the most parsimonious cladograms depicting the biogeographic relationships of Galapagos to the American continents and the intra‐archipelago ones. Analyses of species richness vs. island extents, species sharing vs. distance between islands, and species sharing vs. island extents were performed to assess the distribution patterns of the analysed vertebrates.ResultsGenus distribution‐based PAE results suggest that Galapagos archipelago was settled by South American reptiles. The Galapagos islands cluster with Ecuador, Chile and Peru. A large American clade including Meso‐America, USA, Mexico and Colombia is supported by this work too. Sister group relationships between the Galapagos–western South American clade and the large American clade are not defined. Species distribution‐based PAE results are not able to place the Galapagos into any clade. PAE intra‐archipelago output shows that large islands cluster together, very small islands are placed with lesser confidence because of ecological noise explained by the analyses of species richness vs. extent, shared species vs. distance between islands, and shared species vs. extent relationships. This distribution‐based work supports previously published phylogeny‐based biogeographic analyses and corroborates them with an independent evidence. Two competing colonization models of the archipelago are discussed.
Modern pollen–vegetation and isopoll maps in southern Argentina
Authors: Paez M. M. , Schäbitz F. , Stutz S. 
Published: March 2003

AimTo study the relation between vegetation and pollen spectra as a basic information for the interpretation of Quaternary paleoenvironments.LocationSouthern Argentina between latitude 38–47° S and longitude 62–72° W.MethodsPollen analysis, statistical analysis, geographical information system (GIS).ResultsResults of cluster analysis of pollen surface samples show close relations between the dispersal and composition of pollen taxa in the spectra with the corresponding vegetation formations. First isopoll maps of this region presented here by using GIS, demonstrate the relation between the main pollen taxa, the vegetation and the mean annual precipitation.Main conclusionsThe results prove the usefulness of the method of ‘modern analogues’ for southern Argentina.
Relative influences of patch, landscape and historical factors on birds in an Australian fragmented landscape
Authors: Mac Nally Ralph , Horrocks Gregory 
Published: March 2003

AimAnimal assemblages in fragmented landscapes are likely to be determined by contemporary (e.g. patch size, biotic interactions) and historical (e.g. change in patch area) characteristics of patches and their positioning in the landscape (e.g. connectivity). We considered the influence of habitat structure, landscape context, history and an aggressive, native bird species [the Noisy Miner Manorina melanocephala (Latham 1801)] on three characteristics of woodland‐dependent bird assemblages in a fragmented, eucalypt‐forest landscape. The response variables were: (1) species richness (SR), (2) sums‐of‐densities (i.e. total number of individual birds), and (3) occurrence of rare species [through a rare‐species index (RSI)].LocationBox‐ironbark, eucalypt forests of central Victoria, Australia (broadly bounded by: 36–37° S, 142–146° E).MethodsThere were replicates of four size‐classes of fragments (10, 20, 40, 80 ha) and replicates of the same size‐classes set within large blocks of extant forest. This design allowed us to distinguish between area‐specific and fragmentation effects by comparing same‐sized fragments and reference areas to establish fragmentation‐specific impacts.ResultsSpecies richness was less than expected in smaller fragments and this was apparently because of current fragment area, density of the Noisy Miner and habitat quality. The RSI exhibited similar dependencies, while sums‐of‐densities appeared to be related to the number and quality of wooded linkages to fragments. The historical variable was forested–area change of each fragment between 1963 and 1996, and was found to have no relationship to any of the response variables.Main conclusionsThe lack of historical influence suggested that the avifaunas of the fragments are unlikely to be `relaxing' from isolation effects through local extinctions, but are more likely to be dominated by dynamic recolonization and abandonment both seasonally and among years. The dependence of sums‐of‐densities on the linkage variable appeared to be largely because of the responses of two species, the Red Wattlebird Anthochaera curunculata (Shaw, 1790) and the Yellow‐tufted Honeyeater Lichenostomus melanops (Latham, 1801). These species are among the three most common in the large forest blocks, but are much rarer in fragments. The connectedness effect suggests that these species may depend upon linkages to occupy fragments that are only moderately distant from large forested areas within this region.
A test of the metapopulation model of the species–area relationship
Authors: Matter Stephen F. , Hanski Ilkka , Gyllenberg Mats 
Published: March 2003

AbstractAimThe species–area relationship is a ubiquitous pattern. Previous methods describing the relationship have done little to elucidate mechanisms producing the pattern. Hanski & Gyllenberg (Science, 1997,275, 397) have shown that a model of metapopulation dynamics yields predictable species–area relationships. We elaborate on the biological interpretation of this mechanistic model and test the prediction that communities of species with a higher risk of extinction caused by environmental stochasticity should have lower species–area slopes than communities experiencing less impact of environmental stochasticity.MethodsWe develop the mainland–island version of the metapopulation model and show that the slope of the species–area relationship resulting from this model is related to the ratio of population growth rate to variability in population growth of individual species. We fit the metapopulation model to five data sets, and compared the fit with the power function model and Williams's (Ecology, 1995,76, 2607) extreme value function model. To test that communities consisting of species with a high risk of extinction should have lower slopes, we used the observation that small‐bodied species of vertebrates are more susceptible to environmental stochasticity than large‐bodied species. The data sets were divided into small and large bodied species and the model fit to both.Results and main conclusionsThe metapopulation model showed a good fit for all five data sets, and was comparable with the fits of the extreme value function and power function models. The slope of the metapopulation model of the species–area relationship was greater for larger than for smaller‐bodied species for each of five data sets. The slope of the metapopulation model of the species–area relationship has a clear biological interpretation, and allows for interpretation that is rooted in ecology, rather than ad hoc explanation.