bluuebunny/crossref_metadata_2025_split huggingface dataset:
Physiological indicators of stress in African forest elephants (Loxodonta africana cyclotis) in relation to petroleum operations in Gabon, Central Africa
Authors: Munshi‐South Jason , Tchignoumba Landry , Brown Janine , Abbondanza Nicole , Maldonado Jésus E. , Henderson Ann , Alonso Alfonso 
Published: October 2008

ABSTRACTAim  Human activities are major determinants of forest elephant (Loxodonta africana cyclotis) distribution in Gabon, but the types and intensity of disturbance that elephants can tolerate are not known. We conducted dung surveys within the Gamba Complex of Protected Areas in SW Gabon to examine (1) the feasibility of noninvasive faecal analyses for monitoring stress physiology, and (2) the influence of petroleum operations on stress levels in forest elephants.Location  Gabon, Central Africa.Methods  We identified multiple dung piles from the same individual by matching their eight‐locus microsatellite genotypes, and measured faecal concentrations of glucocorticoid metabolites as an indicator of stress in areas subject to different levels of disturbance: (1) Loango National Park (2) an ‘industrial corridor’ dominated by oil fields, and (3) a nearby area of human settlements.Results  We obtained unique microsatellite genotypes and faecal glucocorticoid metabolite (FGM) concentrations for 150 forest elephant individuals, which is the largest hormonal data set for wild African forest elephants to date. Adults exhibited higher mean FGM concentrations than juveniles, and in contradiction of our expectations of chronic stress around oil fields, elephants in Loango National Park exhibited significantly higher FGM concentrations than elephants in the industrial corridor.Main conclusions  We argue that forest elephants in the industrial corridor of the Gamba Complex have become acclimated to oil fields, resulting in part from oil company regulations that minimize stressful interactions between elephants and petroleum operations. Our findings for a flagship species with substantial ecological requirements bode well for other taxa, but additional studies are needed to determine whether oil operations are compatible over their life span with rain forest ecosystems in Central Africa.
Measuring community responses to large‐scale disturbance in conservation biogeography
Authors: Devictor Vincent , Robert Alexandre 
Published: October 2008

ABSTRACTAim  Which community metrics should be used to reflect community response to large‐scale habitat alterations is unclear. Here, we assess what and how community changes should be measured to accurately track community responses to large‐scale disturbance in space and/or time.Location  France.Method  We first developed a simulation model to examine temporal changes in the species composition of large‐scale metacommunities. Using this model, we assessed how species richness, Shannon index, trends of particular subset of species or community indices of habitat specialization were influenced by different disturbance scenarios, and whether these indices were biased by imperfect detectability. We further used more than 1000 empirical bird communities from the French Breeding Bird Survey recently exposed to disturbances of various intensities as a case study.Results  Our simulation and empirical results both demonstrate that species richness and diversity measures can show confusing trends and even provide misleading messages of communities’ fate. In contrast, reflecting the composition of the community in terms of habitat specialist and generalist species was more robust and powerful to reflect disturbance effects.Main conclusions  We highlight the weakness of using community metrics that fail to incorporate ecological difference among species when summarizing community‐level trends in disturbed landscapes.
Species richness of herbivores on exotic host plants increases with time since introduction of the host
Authors: Brändle Martin , Kühn Ingolf , Klotz Stefan , Belle Christina , Brandl Roland 
Published: October 2008

ABSTRACTAim  Species richness of insect herbivores feeding on exotic plants increases with abundance as well as range size of the host in the area of introduction. The formation of these herbivore assemblages requires a certain amount of time, and the richness of insect faunas should also increase with the length of time an exotic plant has been present in the introduced range.Location  Central Europe.Methods  We analysed the variation in species richness of leaf‐chewing Lepidoptera larvae and sap‐sucking Auchenorrhyncha (Hemiptera) associated with 103 exotic woody plant species in Germany in relation to time since introduction, range size, growth form (trees versus shrubs), biogeographical origin (distance from Central Europe) and taxonomic isolation of the host plant (presence or absence of a native congener in the introduced area).Results  Using simple correlation analyses we found for Lepidoptera and Auchenorrhyncha that species richness increased with time since introduction of the host plant. For the Lepidoptera the increase of species richness with time since introduction remained significant even after removing the effects of all other independent variables.Main conclusions  Our results provide some evidence that assemblages of insects on exotic plants do not reach saturation within a time scale of few hundred years. This contrasts with previous findings for crop plants.
Temporal variability of nestedness and idiosyncratic species in stream insect assemblages
Authors: Heino Jani , Mykrä Heikki , Muotka Timo 
Published: October 2008

ABSTRACTAims   The nested subset pattern has been widely studied in the last 20 years, and recent syntheses have challenged the prevalence of this pattern in nature. We examined the degree of nestedness, its temporal variability and its environmental correlates in stream insects of a boreal drainage system. We also examined differences between nested and idiosyncratic species in site occupancy, niche position and niche breadth.Location   Koutajoki drainage basin in northern Finland.Methods   We used (i) nestedness analyses with three null models for testing the significance of nestedness; (ii) Spearman rank correlation to examine the correlates of nestedness; (iii) outlying mean index analysis to analyse the niche characteristics of species; (iv) and t‐test to examine differences in niche breadth, niche position and site occupancy of idiosyncratic and other nested species.Results   Stream insect assemblages were significantly nested in each of the three study years. The maximally packed matrices were significantly nested according to the nestedness calculator based on null models I (species frequencies and site richness equiprobable) and II (species frequencies fixed and site richness equiprobable), but non‐significant based on a conservative null model III (species frequencies and site richness fixed to those of the observed matrix). The most important correlate of nestedness was stream size, whereas isolation, productivity (total phosphorus) and habitat heterogeneity exhibited non‐significant relationship with nestedness. Idiosyncratic species occurred, on average, at more sites than nested species, mirroring the restricted distributions of several nested species that were inclined towards species‐rich sites. Idiosyncratic and nested species also differed in niche position and niche breadth, with idiosyncratic species having, on average, less marginal niche positions and wider niches than nested species.Main conclusions  Stream size correlated with nestedness, possibly because small streams were inhabited only by species able to persist under, or colonize shortly after, disturbances, while most species could occur at larger sites where disturbances are less severe. From the conservation perspective, our findings suggest that stream size really matters, given that sites with high species richness and many rare species are more likely to occur in larger streams. However, also the requirements of idiosyncratic species should be accommodated in conservation planning.
Long‐term variability of Abies alba in NW Romania: implications for its conservation management
Authors: Feurdean Angelica , Willis Katherine J. 
Published: October 2008

ABSTRACTAim  Although Abies alba is not yet prioritized for conservation in many European countries, its importance is acknowledged under the EU Directive on the marketing for forest reproductive material. The Apuseni National Park contains one of the largest areas of remnant native A. alba in central eastern Europe. Here, we examine the antiquity of the present A. alba communities in the forests of NW Romania and the drivers behind their variability over the last 6000 years leading to current distribution pattern.Location  The Apuseni National Park (ANP), NW Romania.Methods  We use fossil pollen, microscopic and macroscopic charcoal and AMS14C dating on four sedimentary sites in the west‐central ANP.Results  The results reveal that stands of A. alba have been growing in NW Romania from at least 5700 yr bp and occurred in low abundance until 4200 yr bp. A. alba expanded thereafter and it thrived in multispecies forest stands with Fagus, Picea, Carpinus, Tilia, Quercus and Ulmus between 4200 and 1200 yr bp. The initial expansion occurred during an independently documented period of high moisture and cooler temperature as inferred from isotope data from cave stalagmites within this region. The final decline in A. alba abundance and distribution started from about 1200 yr bp and reached an unprecedently low value over the last 300 years, which was primarily caused by the increase in human activities in the region through deforestation, forest browsing and burning, and commercial forestry.Main conclusion  Different management strategies ranging from restriction on harvesting and browsing need to be implemented in this region if A. alba is going to survive the forecasted decrease in precipitation and increase in temperature, which will further reduce its spatial distribution.
European map of alien plant invasions based on the quantitative assessment across habitats
Authors: Chytrý Milan , Pyšek Petr , Wild Jan , Pino Joan , Maskell Lindsay C. , Vilà Montserrat 
Published: October 2008

ABSTRACTAim  Recent studies using vegetation plots have demonstrated that habitat type is a good predictor of the level of plant invasion, expressed as the proportion of alien to all species. At local scale, habitat types explain the level of invasion much better than alien propagule pressure. Moreover, it has been shown that patterns of habitat invasion are consistent among European regions with contrasting climates, biogeography, history and socioeconomic background. Here we use these findings as a basis for mapping the level of plant invasion in Europe.Location  European Union and some adjacent countries.Methods  We used 52,480 vegetation plots from Catalonia (NE Spain), Czech Republic and Great Britain to quantify the levels of invasion by neophytes (alien plant species introduced after ad 1500) in 33 habitat types. Then we estimated the proportion of each of these habitat types in CORINE land‐cover classes and calculated the level of invasion for each class. We projected the levels of invasion on the CORINE land‐cover map of Europe, extrapolating Catalonian data to the Mediterranean bioregion, Czech data to the Continental bioregion, British data to the British Isles and combined Czech–British data to the Atlantic and Boreal bioregions.Results  The highest levels of invasion were predicted for agricultural, urban and industrial land‐cover classes, low levels for natural and semi‐natural grasslands and most woodlands, and the lowest levels for sclerophyllous vegetation, heathlands and peatlands. The resulting map of the level of invasion reflected the distribution of these land‐cover classes across Europe.Main conclusions  High level of invasion is predicted in lowland areas of the temperate zone of western and central Europe and low level in the boreal zone and mountain regions across the continent. Low level of invasion is also predicted in the Mediterranean region except its coastline, river corridors and areas with irrigated agricultural land.
Threats and biodiversity in the mediterranean biome
Authors: Underwood Emma C. , Viers Joshua H. , Klausmeyer Kirk R. , Cox Robin L. , Shaw M. Rebecca 
Published: October 2008

ABSTRACTAim  Global conservation assessments recognize the mediterranean biome as a priority for the conservation of the world's biodiversity. To better direct future conservation efforts in the biome, an improved understanding of the location, magnitude and trend of key threats and their relationship with species of conservation importance is needed.Location  Mediterranean‐climate regions in California‐Baja California, Chile, South Africa, Australia and the Mediterranean Basin.Methods  We undertook a systematic, pan‐regional assessment of threats in the mediterranean biome including human population density, urban area and agriculture. To realize the full implications of these threats on mediterranean biodiversity, we examined their relationship with species of conservation concern: threatened mammals at the global scale and threatened plants at the subecoregional scale in California, USA.Results  Across the biome, population density and urban area increased by 13% and agriculture by 1% between 1990 and 2000. Both population density and urban area were greatest in California‐Baja California and least in Australia while, in contrast, agriculture was greatest in Australia and least in California‐Baja California. In all regions lowlands were most affected by the threats analysed, with the exception of population density in the Chilean matorral. Threatened species richness had a significant positive correlation with population density at global and subecoregional scales, while threatened species were found to increase with the amount of urban area and decrease as the amount of natural area and unfragmented core area increased.Main conclusions  Threats to mediterranean biodiversity have increased from 1990 to 2000, although patterns vary both across and within the five regions. The need for future conservation efforts is further underlined by the positive correlation between species of conservation concern and the increase in population density over the last decade. Challenges to reducing threats extend beyond those analysed to include human–environmental interactions and their synergistic effects, such as urbanization and invasive species and wildfires.
Global biogeographical data bases on marine fishes: caveat emptor
Authors: Robertson D. Ross 
Published: October 2008

ABSTRACTA review of georeferenced collection‐site records for Caribbean shore‐fishes served by major online distributors of aggregated biodiversity data found large‐scale errors in over a third of the species and genera, in nearly two‐thirds of the families. To avoid compromising the value of their services to the global science community online providers must actively address the question of data quality.
Foundations for conservation of intraspecific genetic diversity revealed by analysis of phylogeographical structure in the endangered endemic lizard Podarcis lilfordi
Authors: Terrasa B. , Pérez‐Mellado V. , Brown R. P. , Picornell A. , Castro J. A. , Ramon M. M. 
Published: October 2008

ABSTRACTAim  To describe and analyse phylogeographical patterns in the endangered endemic lizard Podarcis lilfordi from across its remaining range and thereby establish baseline information on genetic diversity that will help determine conservation priorities and assist future reintroduction programs.Location  Balearic Islands, Spain.Methods  We analysed mitochondrial DNA (2382 bp sequence from eight genes) from 118 individuals and characterized the relationships among haplotypes using parsimony networks, as well as phylogenetic inference. Analyses of historical gene flow and population growth were used to provide further insights into population histories.Results  Four unconnected parsimony networks were obtained that mirrored the main clades in the phylogenetic tree: (I) all Menorcan populations, (II) Dragonera, Malgrats and Toro islands (Western Mallorca) (III and IV) and the remaining populations from Cabrera and Mallorca. Two major haplotype groups were detected in Menorca (I) and these provided signatures of a demographic expansion and asymmetrical historical gene flow, respectively, concordant with the expected direction of colonization from south to north of the island. Populations from western Mallorca (II) showed evidence of historical allopatric fragmentation events following isolation around the start of the Pleistocene. In networks III and IV, Cabreran populations appear to have become isolated from north and south Mallorca quite recently, with asymmetric gene flow indicating a northwards dispersal direction.Main conclusions  P. lilfordi is a genetically diverse species that shows substantial mtDNA structuring both between regions and, at a finer scale, between some islet populations within regions. The precarious state of some islet populations shown here to be quite divergent (e.g. Toro island in western Mallorca) means that conservation of this intraspecific biodiversity requires urgent action.
Reducing redundancy in invasion ecology by integrating hypotheses into a single theoretical framework
Authors: Catford Jane A. , Jansson Roland , Nilsson Christer 
Published: October 2008

ABSTRACTAim  Invasion ecology includes many hypotheses. Empirical evidence suggests that most of these can explain the success of some invaders to some degree in some circumstances. If they all are correct, what does this tell us about invasion? We illustrate the major themes in invasion ecology, and provide an overarching framework that helps organize research and foster links among subfields of invasion ecology and ecology more generally.Location  Global.Methods  We review and synthesize 29 leading hypotheses in plant invasion ecology. Structured around propagule pressure (P), abiotic characteristics (A) and biotic characteristics (B), with the additional influence of humans (H) on P, A and B (hereon PAB), we show how these hypotheses fit into one paradigm. P is based on the size and frequency of introductions, A incorporates ecosystem invasibility based on physical conditions, and B includes the characteristics of invading species (invasiveness), the recipient community and their interactions. Having justified the PAB framework, we propose a way in which invasion research could progress.Results  By highlighting the common ground among hypotheses, we show that invasion ecology is encumbered by theoretical redundancy that can be removed through integration. Using both holistic and incremental approaches, we show how the PAB framework can guide research and quantify the relative importance of different invasion mechanisms.Main conclusions  If the prime aim is to identify the main cause of invasion success, we contend that a top‐down approach that focuses on PAB maximizes research efficiency. This approach identifies the most influential factors first, and subsequently narrows the number of potential causal mechanisms. By viewing invasion as a multifaceted process that can be partitioned into major drivers and broken down into a series of sequential steps, invasion theory can be rigorously tested, understanding improved and effective weed management techniques identified.
Predicting global abundance of a threatened species from its occurrence: implications for conservation planning
Authors: Figueiredo Marcos S. L. , Grelle Carlos Eduardo V. 
Published: October 2008

AbstractAim Global abundance is an important characteristic of a species that is correlated with geographical distribution and body size. Despite its importance these estimates are not available since reliable field estimates are either expensive or difficult to obtain. Based on the relationship between a species’ local abundance and distribution, some authors propose that abundance can be obtained through spatial distribution data from maps plotted at different scales. This has never been tested over the entire geographical range of a species. Thus, the aim of this study was to estimate global abundance of the Neotropical primateBrachyteles hypoxanthus(northern muriqui) and compare the results with available field estimates.Location From southern Bahia to Minas Gerais and Espírito Santo states, in the Brazilian Atlantic rain forest.Methods We compiled 25 recent occurrence localities ofB. hypoxanthusand plotted them in grid cells of five different sizes (1, 25, 50, 75 and 100 km per side) to evaluate the performance and accuracy of abundance estimates over a wide range of scales. The abundance estimates were obtained by the negative binomial distribution (NBD) method and corrected by average group size to take into account primate social habits. To assess the accuracy of the method, the predicted abundances were then compared to recent independent field estimates.Results The NBD estimates were quite accurate in predictingB. hypoxanthusglobal abundance, once the gregarious habits of this species are taken into account. The predicted abundance estimates were not statistically different from those obtained from field estimates.Main conclusions The NBD method seems to be a quick and reliable approach to estimate species abundance once several limiting factors are taken into account, and can greatly impact conservation planning, but further applications in macroecological and ecological theory testing needs improvement of the method.
Habitat diversity, ecological requirements of species and the Small Island Effect
Authors: Sfenthourakis Spyros , Triantis Kostas A. 
Published: October 2008

ABSTRACTAim  To explore the causal factors leading to a significant Small Island Effect (SIE), that is, the absence of the commonly found species–area relationships below an island size, on the terrestrial isopod communities from a large number of islands.Location  Ninety islands of the Aegean Sea (Greece).Methods  The detection of a significant SIE is assessed through the application of all three methods available in the literature. Species are divided into generalists and specialists. We tested if the minimum area and the area range of each species’ occurrences differ between generalists and specialists. Next, we searched for differences in the ratios of specialists to generalists above and below the SIE threshold, and tested their cumulative ratios when islands are arranged according to increasing area, altitude or habitat diversity in order to identify the threshold where they become statistically indistinguishable from the ratio of the total set of islands.Results  Our results indicate a strong effect of habitat availability on the SIE. Communities of islands within the SIE range, host a higher percentage of generalists. An analysis of the specific habitat requirements shows that, for isopods, the crucial factor is the lack of habitats related to inland waters from small islands.Main conclusions  The distribution of habitats on islands of different size is of major importance for the occurrence of a SIE. The relative representation of specialist and generalist species on islands of different size plays an important role in shaping SIE‐related patterns. Conservation efforts should pay special attention on freshwater habitats, especially on small Aegean islands. Identifying the causal factors of SIE, combined with a thorough knowledge of the ecological requirements of species can offer insights into identifying habitat types and groups of species that are more vulnerable to alterations of the environment.