bluuebunny/crossref_metadata_2025_split huggingface dataset:
Correlates of extinction proneness in tropical angiosperms
Authors: Sodhi Navjot S. , Koh Lian Pin , Peh Kelvin S.‐H. , Tan Hugh T. W. , Chazdon Robin L. , Corlett Richard T. , Lee Tien Ming , Colwell Robert K. , Brook Barry W. , Sekercioglu Cagan H. , Bradshaw Corey J. A. 
Published: February 2009

ABSTRACTRapid losses and degradation of natural habitats in the tropics are driving catastrophic declines and extinctions of native biotas, including angiosperms. Determining the ecological and life‐history correlates of extinction proneness in tropical plant species may help reveal the mechanisms underlying their responses to habitat disturbance, and assist in the pre‐emptive identification of species at risk from extinction. We determined the predictors of extinction proneness in 1884 locally extinct (n = 454) and extant (n = 1430) terrestrial angiosperms (belonging to 43 orders, 133 families, and 689 genera) in the tropical island nation of Singapore (699.4 km2), which has lost 99.6% of its primary lowland evergreen rainforest since 1819. A wide variety of traits such as geographical distribution, pollination system, sexual system, habit, habitat, height, fruit/seed dispersal mechanism, and capacity for vegetative re‐sprouting were used in the analysis. Despite controlling for phylogeny (as approximated by family level classification), we found that only a small percentage of the variation in the extinction probability could be explained by these factors. Epiphytic, monoecious, and hermaphroditic species and those restricted to inland forests have higher probabilities of extinction. Species dependent on mammal pollinators also probably have higher extinction probabilities. More comparative studies that use species traits to identify extinction‐prone plant species are needed to guide the enormous, but essential task of identifying species most in need of conservation action.
Do cities export biodiversity? Traffic as dispersal vector across urban–rural gradients
Authors: von der Lippe Moritz , Kowarik Ingo 
Published: February 2009

ABSTRACTUrban areas are among the land use types with the highes richness in plant species. A main feature of urban floras is the high proportion of non‐native species with often divergent distribution patterns along urban–rural gradients. Urban impacts on plant species richness are usually associated with increasing human activity along rural‐to‐urban gradients. As an important stimulus of urban plant diversity, human‐mediated seed dispersal may drive the process of increasing the similarity between urban and rural floras by moving species across urban–rural gradients. We used long motorway tunnels as sampling sites for propagules that are released by vehicles to test for the impact of traffic on seed dispersal along an urban–rural gradient. Opposite lanes of the tunnels are separated by solid walls, allowing us to differentiate seed deposition associated with traffic into vs. out of the city. Both the magnitude of seed deposition and the species richness in seed samples from two motorway tunnels were higher in lanes leading out of the city, indicating an ‘export’ of urban biodiversity by traffic. As proportions of seeds of non‐native species were also higher in the outbound lanes, traffic may foster invasion processes starting from cities to the surrounding landscapes. Indicator species analysis revealed that only a few species were confined to samples from lanes leading into the city, while mostly species of urban habitats were significantly associated with samples from the outbound lanes. The findings demonstrate that dispersal by traffic reflects different seed sources that are associated with different traffic directions, and traffic may thus exchange propagules along the urban–rural gradient.
Ecological and historical factors affecting distribution pattern and richness of endemic plant species: the case of the Maritime and Ligurian Alps hotspot
Authors: Casazza Gabriele , Zappa Elena , Mariotti Mauro G. , Médail Frédéric , Minuto Luigi 
Published: February 2009

ABSTRACTThe aim of this study was to test a method to locate all the foci, centres, and areas of endemism in a biodiversity hotspot in order to understand the influence of ecological and historical factors on the distribution pattern and to identify priority areas for future conservation projects. The study area was the Maritime and Ligurian Alps hotspot.Analyses were performed on the presence/absence matrix of 36 vascular plant taxa endemic to the study area. For each operational geographical unit, the number of endemic taxa present was counted. Additionally, the weighted endemism value was calculated. Areas of endemism were distinguished using cluster analysis and parsimony analysis of endemicity. The influence of ecological characteristics and historical factors was evaluated using Multi‐Response Permutation Procedure and the Nonparametric Multiplicative Regression. The Indicator Species Analysis (INDVAL) method was used to identify the species characterizing the areas of endemism. Our results show the importance and location of four main areas of endemism within the Maritime and Ligurian Alps and explain the distribution pattern of endemic plants. These areas are easily interpreted by historical and ecological factors, and INDVAL indicates which taxa took part in the history of each endemism area.
Geographical range size of tropical plants influences their response to anthropogenic activities
Authors: Lozada Tannya , de Koning G. H. J. , Kessler Michael , Klein Alexandra‐Maria , Tscharntke Teja 
Published: February 2009

ABSTRACTBiodiversity patterns may be influenced by the species geographical range sizes, but this is rarely shown. We used a highly replicated and large‐scale study in coastal Ecuador to determine for the first time the importance of latitudinal range size of plant species in their response to land‐use activities. We examined herbaceous plant communities of five land‐use types with decreasing anthropogenic disturbance (from the most intervened rice and pasture to the less intervened managed agroforest, abandoned agroforest, and forest) in a low and a high impact human‐dominated landscape. All species were classified in four latitudinal range size quartiles, from the 25% species with the narrowest to the 25% with the widest range size. We found notable differences between patterns of total species richness and those of individual range size quartiles. Whereas total species richness was higher in more intervened land‐use types, percentages of narrow‐ranged species were significantly higher in less intervened land‐use types. In contrast, percentages of wide‐ranging species were higher in more intervened land‐use types. Hence, responses of plant species to human activities were influenced by traits that determine their range sizes. An analysis of floristic similarity between land‐use types revealed that narrow‐ranged species were mainly preserved in forest fragments, but the other land‐use types supported many unique narrow‐ranged species and therefore made an important contribution to their preservation at the landscape level. Conservation efforts should combine protection of natural habitats with strategies to maintain a diversity of low‐intensity land‐use types, looking for win‐win solutions or trade‐offs between biodiversity conservation and human welfare in human‐dominated landscapes.
Elephant management: why can't we throw out the babies with the artificial bathwater?
Authors: Chamaillé‐Jammes Simon , Valeix Marion , Fritz Hervé 
Published: February 2009

ABSTRACTElephant management is highly controversial and any elephant‐related study is quickly seen as a pro or con for one of the usual elephant management practices (laissez‐faire, culling, contraception or metapopulation management). Managing water sources has also been suggested as one option, even though no experimental data exist. In a recent issue of Diversity and Distributions, Smit et al. (2007) rejected this management tool as an efficient method to control elephant distribution and dynamics in Kruger National Park, South Africa. However, we believe that (1) Smit et al.'s conclusion is poorly supported by the available data, and (2) that this non‐intrusive management tool has the potential for being one of the few practices able to reconcile managers, scientists, and the public opinion in the never‐ending ‘elephant problem’. For these reasons, we believe that the strong conclusions of Smit et al. should be moderated.
Climatic seasonality, resource bottlenecks, and abundance of rainforest birds: implications for global climate change
Authors: Williams Stephen E. , Middleton Jeffery 
Published: February 2009

ABSTRACTWe demonstrate that within‐year climatic variability, particularly rainfall seasonality, is the most significant variable explaining spatial patterns of bird abundance in Australian tropical rainforest. The likely mechanism causing this pattern is a resource bottleneck (insects, nectar, and fruit) during the dry season that limits the population size of many species. The patterns support both the diversity–climatic–stability hypothesis and the species–energy hypothesis but clearly show that seasonality in energy availability may be a more significant factor than annual totals or means. An index of dry season severity is proposed that quantifies the combined effect of the degree of dryness and the duration of the dry season. We suggest that the predicted increases in seasonality due to global climate change could produce significant declines in bird abundance, further exacerbating the impacts of decreased range size, increased fragmentation, and decreased population size likely to occur as a result of increasing temperature. We suggest that increasing climatic seasonality due to global climate change has the potential to have significant negative impacts on tropical biodiversity.
Life history and population size variability in a relict plant. Different routes towards long‐term persistence
Authors: García María B. 
Published: February 2009

ABSTRACTA central tenet of conservation biology is that population size affects the persistence of populations. However, many narrow endemic species combine small population ranges and sizes with long persistence, thereby challenging this tenet. I examined the performance of three different‐sized populations of Petrocoptis pseudoviscosa (Caryophyllaceae), a palaeoendemic rupicolous herb distributed along a small valley in the Spanish Pyrenees. Reproductive and demographic parameters were recorded over 6 years, and deterministic and stochastic matrix models were constructed to explore population dynamics and extinction risk. Populations differed greatly in structure, fecundity, recruitment, survival rate, and life span. Strong differentiation in life‐history parameters and their temporal variability resulted in differential population vulnerability under current conditions and simulated global changes such as habitat fragmentation or higher climatic fluctuations. This study provides insights into the capacity of narrow endemics to survive both at extreme environmental conditions and at small population sizes. When dealing with species conservation, the population size–extinction risk relationship may be too simplistic for ancient, ecologically restricted organisms, and some knowledge of life history may be most important to assess their future.
Response to De Silva et al. (2007): Endemic freshwater finfish of Asia: distribution and conservation status
Authors: Darwall William R. T. , Pollock Caroline M. , Smith Kevin G. , Vié Jean‐Christophe 
Published: February 2009

ABSTRACT De Silva et al. (2007) present an overview of the distribution and conservation status of the endemic freshwater fish of Asia. Within that review they use data from the IUCN Red List of Threatened Species™ (2006) to conduct an analysis of the conservation status of those endemic fish species. Their analysis is incorrect and provides a very misleading impression of the level of threat to Asian freshwater fish and to freshwater fish at the global scale. The errors stem from a misinterpretation of the data presented on the IUCN Red List. The sources of errors are discussed below and the opportunity is taken to clarify what the information on the IUCN Red List represents.
Land‐cover and land‐use change and its contribution to the large‐scale organization of Puerto Rico's bird assemblages
Authors: Acevedo Miguel A. , Restrepo Carla 
Published: February 2009

ABSTRACTGlobal biodiversity is changing rapidly driven by human alteration of habitat, and nowhere this is more dramatic than in insular habitats. Yet land‐cover change is a complex phenomenon that not only involves habitat destruction but also forest recovery over different time scales. Therefore, we might expect species to respond in diverse ways with likely consequences for the reorganization of regional assemblages. These changes, however, may be different in tropical islands because of their low species richness, generalist habits and high proportion of endemics. Here, we focus on the island of Puerto Rico and ask how island‐wide changes in land cover and land use has influenced the large‐scale organization of bird assemblages. To address this question, we combined in a Geographical Information System (GIS) the first 6 years (1997–2002) of the Puerto Rican Breeding Bird Survey (PR‐BBS) with land‐cover and land‐use data extracted from a published digital map derived from the classification of Landsat images. A Non‐metric Multidimensional Scaling (NMS) ordination based on the composition and abundance of birds, and percentage land‐use types showed that land use followed by climate could explain most of the variation observed among routes in terms of species composition and abundance. Moreover, endemic and exotic species were widely distributed throughout the island, but the proportion of endemic species is higher in closed forests while exotic species are more abundant in open habitats. However, historical accounts from the early 1900s indicate that endemic species were distributed across the entire island. Today, most of the land cover transformation in Puerto Rico occurs in the lowlands which may explain the high abundance of endemic species in cloud forests and the high abundance of exotic species in open habitats in the lowlands.
Garden bird feeding predicts the structure of urban avian assemblages
Authors: Fuller Richard A. , Warren Philip H. , Armsworth Paul R. , Barbosa Olga , Gaston Kevin J. 
Published: February 2009

ABSTRACTHouseholds across the developed world cumulatively spend many millions of dollars annually on feeding garden birds. While beneficial effects on avian assemblages are frequently claimed, the relationships between levels of garden bird feeding and local avian populations are unknown. Using data from a large UK city, we show that both avian species richness and abundance vary across different socioeconomic neighbourhood types. We examined whether patterns in bird feeding could explain this variation. The density of bird feeding stations across the urban environment was strongly positively related to avian abundance, after controlling for differences in habitat availability. This effect was almost exclusively driven by the abundance of those species known to utilize garden feeding stations frequently. In contrast, the density of feeding stations had no effect on avian species richness. We also examined variation in the proportion of households in different communities that provide food for birds, a factor that is not correlated with feeder density. The prevalence of bird feeding across different neighbourhoods declined as socioeconomic deprivation increased, and increased with avian species richness and abundance. Our results suggest that the provision of supplementary food for birds by multiple landowners across a city can impact the status of urban bird populations. The potential for harnessing these actions for conservation needs to be explored.
Integration of palaeontological, historical, and geographical data on the extinction of koa‐finches
Authors: James Helen F. , Price Jonathan P. 
Published: February 2009

ABSTRACTIdentifying the root causes of extinction or endangerment requires long chronological records that begin before a population started to decline and extend until its extinction or functional extinction. We present a case study of the koa‐finches, genus Rhodacanthis, an extinct group of Hawaiian honeycreepers that was specialized to feed on green pods and seeds of the koa tree or other leguminous plants. Six island populations of koa‐finches are known; four in the Holocene fossil record and two that survived until the 1890s. We document the palaeoecological context of the fossils and identify constraints on the age span of the specimen record for each population using stratigraphic contexts, associated radiometric determinations, and museum specimen data. We estimate the potential geographical range of koa‐finches at the time of human arrival using two methods: assessment of their historical and palaeo‐habitats, and geographical information system mapping of the pre‐human distribution of the koa plant (Acacia koa) and its sister species, the koai‘a plant (Acacia koaia). After integrating the foregoing data with chronological records and distributional maps of the potential forcing agents of extinction, we conclude that at least two extinctions of island populations were due to ecological change in the lowlands in the prehistorical and perhaps the early historical periods. In the same time frame, the koa‐finch populations on Hawai‘i Island became rare and restricted to upland refugia, making them vulnerable to the upland forest harvesting and degradation that was accelerating in the 1890s. Neither climatic variation nor mosquito‐vectored diseases are likely to have caused the observed extinctions. This study illustrates an approach that can be applied to many other extinct and endangered island species to better understand the causes of high extinction rates in the human era.
Concordance among stream assemblages and spatial autocorrelation along a fragmented gradient
Authors: Grenouillet Gaël , Brosse Sébastien , Tudesque Loïc , Lek Sovan , Baraillé Yasmina , Loot Géraldine 
Published: February 2009

ABSTRACTPatterns of spatial autocorrelation of biota and distributional similarity (concordance) between assemblages of different organism groups have important implications in both theoretical ecology and biodiversity conservation. Here we report environmental gradients and spatial distribution patterns of taxonomic composition among stream fish, benthic macroinvertebrate, and diatom assemblages along a fragmented stream in south‐western France. We quantified spatial patterns of lotic assemblage structure along this stream, and we tested for concordance in distribution patterns among the three taxonomic groups. Our results showed that both environmental characteristics and stream assemblages were spatially autocorrelated. For stream fish and diatom assemblages, these patterns reflected assemblage changes along the longitudinal stream gradient, whereas environmental variables and benthic macroinvertebrates exhibited a more patchy spatial pattern. Cross‐taxa concordance was significant between stream fish and diatoms, and between stream fish and benthic macroinvertebrates. The assemblage concordance between stream fish and diatoms could be attributed to similar responses along the longitudinal gradient, whereas those between stream fish and benthic macroinvertebrates may result from biotic interactions. Based on potential dispersal capacities of taxa, our results validated the hypotheses that weakly dispersing taxa exhibit greater concordance than highly dispersing ones and that dispersal capacities affect how taxonomic groups respond to their local environment. Both diatoms and highly dispersing stream fish were affected by stream fragmentation (i.e. the number of dams between sites), while the effect of fragmentation was not significant for invertebrates that fly well in their adult stage, thus emphasizing the importance of the way of dispersal. These results suggest that addressing the effects of dispersal capacity on stream assemblage patterns is crucial to identifying mechanisms behind patterns and to better understanding the determinants of stream biodiversity.
The performance ofPolylepis australistrees along their entire altitudinal range: implications of climate change for their conservation
Authors: Marcora Paula , Hensen Isabell , Renison Daniel , Seltmann Peggy , Wesche Karsten 
Published: February 2009

ABSTRACTAltitudinal gradients are expected to heavily influence the general performance of mountain tree species. For this study we evaluated vitality, radial growth and reproductive efficiency inPolylepis australis(Rosaceae) throughout its complete altitudinal range in central Argentina. We selected seven forest fragments ranging from 900 to 2700 m a.s.l. In the field, we subjectively assigned vitality and seed productivity indexes to 12P. australistrees per fragment. In addition, we cored and assessed for radial growth 10–18 trees per altitudinal level. In the laboratory, we individually weighed seeds from four or five trees from each altitudinal level and divided into two seed mass classes (light and heavy). We then tested for germination and monitored their seedlings for survival. Seedlings of three trees per altitudinal level were harvested after 40 days and assessed for dry mass. Seedlings of one to two trees per altitudinal level were monitored for survival until both leaves and roots had died. Our main results showed two types of responses to altitude: a unimodal relationship with an optimum at intermediate altitudes of around 1800 m a.s.l. for tree vitality, radial growth, seed productivity and seed mass; and an increase with altitude for in‐vitro seed germination and seedling survival. A rise in temperature due to climate change could restrictP. australisto the upper most altitudes, where conservation of these forests will be a priority.