Distribution Area Of Species Research Articles

Habitat selection of two sympatric species of Ameiva in East Costa Rica

Identifying the differences in habitat use for sympatric species is important for understanding the species preferences and the limits of population distribution. We studied the differences in the habitat use of two understudied sympatric species of Ameiva ( A. festiva and A. quadrilineata ) in a natural reserve of the Caribbean coast of Coast Rica. Ameiva quadrilineata showed a more restrictive habitat use pattern than A. festiva . A. quadrilineata’s smaller body size may be one of the factors limiting its habitat range. Both species showed higher density in regenerated forests, while A. quadrilineata was never found in swamp forests. The air temperature and the meteorological condition at the moment of the survey also influenced the occurrence of the A. quadrilineata, while the juveniles of A. festiva were only affected by the meteorological condition. None of the studied variables seemed to affect the occurrence of A. festiva adults. The results of this study can be useful to evaluate possible changes in the species distribution patterns as a consequence of direct (i.e., deforestation) or indirect (i.e., climate change) human activities in the distribution area of these species.

Influence of drought on tree rings and tracheid features of Pinus nigra and Pinus sylvestris in a mesic Mediterranean forest

We investigated the influence of climate on the ring width and xylem anatomy of two co-occurring pines (Pinus nigra Arn. and P. sylvestris L.) in the mountains of east-central Spain in order to test their utility for dendroclimatic reconstructions. We developed chronologies of ring width, mean lumen diameter and mean cell-wall thickness (in the earlywood, latewood, and the total annual ring) and the number of cells between 1960 and 2006. Drought, expressed as the standardized precipitation-evapotranspiration index (SPEI), was the main climatic driver of tree radial growth, although trees were also sensitive to temperature (negative effect in previous autumn and current summer) and precipitation (with a general positive effect). P. sylvestris response was stronger to climate of the current year, whereas the effect of previous-year climate was more important for P. nigra. Warm and dry summers reduced ring width, tracheid lumen, and wall thickness in both species, whereas warm winter-spring temperatures had the opposite effect, primarily for P. sylvestris. Previous-year or early-season conditions mainly affected earlywood features, whereas latewood was more responsive to summer climate. Overall, climate appeared to be a stronger limiting factor for P. sylvestris. During periods of drought, cell-wall thickness was reduced while lumen width increased in the latewood of P. sylvestris. This could compromise its hydraulic safety against drought-induced cavitation as our site was close to the southern and dry edge of the species distribution area. Our results suggest that anatomical variables record different and stronger climate information than ring width variables, especially in P. sylvestris. Reconstruction models for SPEI at the 3-month scale were developed for July–August and September–October using principal components regression. The best models included anatomical and width variables of both pine species suggesting that tracheid chronologies can be useful for drought reconstructions especially at mesic sites or with species that encode a mixed drought and temperature-precipitation signal.

The deep-sea recruitment of Aristeus antennatus (Risso, 1816) (Crustacea: Decapoda) in the Mediterranean Sea

Recruitment of Aristeus antennatus over the species' entire depth range and distribution area in the Mediterranean Sea is described. Because of the dearth of information on the recruitment of deep-sea species in the literature, the findings reported here take on special significance. Samples were collected at depths between 900 and 2800m on seven trawl surveys using three samplers: an OTMS trawl, an Agassiz bottom frame trawl, and a Macer-Giroq suprabenthic sledge, computing a total of 80, 26 and 14 trawls, respectively. Early juveniles (≤15mm CL) were observed to be present down to a depth of 2800m and to attain maximum percentage abundance between 1350 and 2000m. Spring was the season of peak abundance for juveniles. Several hypotheses explaining this deep-sea recruitment are discussed, including oceanographic events coupled with enrichment of the bathyal bottoms and competitive exclusion in deep-sea species. Studying the deep-sea recruitment of A. antennatus contributes to our understanding of the species' life history and supplies knowledge essential to proper management and sustainable exploitation of the species.

Bud and shoot structure may relate to the distribution area of South American Proteaceae tree species

The capacity of preformation and neoformation and the structure of winter buds are vegetative attributes that may vary between plant species and according to ontogenetic stages of the same species. The present study describes and evaluates these features for the four tree species of Proteaceae occurring in Patagonia. In particular, it analyzes the structure and development of the distal buds of the trunk and the preformed or neoformed nature of the organs involved. Two of the species, Embothrium coccineum and Lomatia hirsuta, have scaly buds, in which primordia of green leaves are covered by cataphylls. The shoots of both species may include neoformed organs, more frequently so in juvenile trees. Lomatia ferruginea and Gevuina avellana have naked buds with a low number of primordia; in juvenile and adult trees of both species trunk shoots are entirely preformed. The structure of buds and shoots suggests two different growth modalities of the axes, which would be related to ecological breadth (narrower in the species with naked buds than in those with scaly buds) and distribution area of these species. The considerable morphological differences between the two Lomatia species studied raise the question whether they ought to be included in the same genus.

Global climate change will severely decrease potential distribution of the East Asian coldwater fish Rhynchocypris oxycephalus (Actinopterygii, Cyprinidae)

Global climate change has been suggested to cause decrease of distribution area of many species. However, this has not been tested for East Asian inland coldwater fish. Chinese minnow (Rhynchocypris oxycephalus) is a small typical coldwater fish, which is endemic to East Asia and generally inhabits stream headwaters. Due to its occurrence in temperate south China, there is growing concern about its future fate in the face of global warming. In this study, we employed maximum entropy approach to analyze how distribution of this species would be impacted by future climate change. We collected data of 310 independent distribution points and 20 environmental variables, and conducted modeling under three general circulation models assuming two gas emission scenarios for 2020s, 2050s, and 2080s. The results showed that the Min temperature of coldest month was the most important climatic variable for potential distribution of the Chinese minnow. Modeling predicted geographical distribution of the Chinese minnow would shrink over time and become much more limited in all the situations especially in South-eastern China, and there would be little suitable habitat left in this region by 2080s. Our results confirm that climate change clearly poses a severe threat to the Chinese minnow, and we suggest that conservation efforts should focus on lower temperature areas within the current range, because these areas will remain relatively cool and may be still suitable for the Chinese minnow even under the most drastic climate change scenarios.

Coupling ecosystem and landscape models to study the effects of plot number and location on prediction of forest landscape change

A fundamental but unsolved dilemma is that observation and prediction scales are often mismatched. Reconciling this mismatch largely depends on how to design samples on a heterogeneous landscape. In this study, we used a coupled modeling approach to investigate the effects of plot number and location on predicting tree species distribution at the landscape scale. We used an ecosystem process model (LINKAGES) to generate tree species response to the environment (a land type) at the plot scale. To explore realistic parameterization scenarios we used results from LINKAGES simulations on species establishment probabilities under the current and warming climate. This allowed us to design a series of plot number and location scenarios at the landscape scale. Species establishment probabilities for different land types were then used as input for the forest landscape model (LANDIS) that simulated tree species distribution at the landscape scale. To investigate the effects of plot number and location on forest landscape predictions, LANDIS considered effects of climate warming only for the land types in which experimental plots were placed; otherwise inputs for the current climate were used. We then statistically examined the relationships of response variables (species percent area) among these scenarios and the reference scenario in which plots were placed on all land types of the study area. Our results showed that for species highly or moderately sensitive to environmental heterogeneity, increasing plot numbers to cover as many land types as possible is the strategy to accurately predict species distribution at the landscape scale. In contrast, for species insensitive to environmental heterogeneity, plot location was more important than plot number. In this case, placing plots in land types with large area of species distribution is warranted. For some moderately sensitive species that experienced intense disturbance, results were different in different simulation periods. Results from this study may provide insights into sample design for forest landscape predictions.

Quantitative estimation of distribution area parameters: A case study of members of the genus Rana

Quantitative analysis of “point” distribution areas of species is analyzed; this method interpolates species distribution to the whole territory based on its correlations with climatic and landscape variables. It is demonstrated that the application of standard statistical interpolation techniques is inappropriate. The new approach uses the interpolation of the species-specific relations with environmental variables determined at individual points to the whole territory. The basic method for solving this problem is factor analysis. This study analyzed methods for quantifying species relations to particular climate and relief variables. Efficiency of this analysis is demonstrated by a case study of three brown frog species: Rana temporaria, R. arvalis, and R. amurensis.

Disregarding the edaphic dimension in species distribution models leads to the omission of crucial spatial information under climate change: the case of Quercus pubescens in France

AbstractSpecies distribution modelling is an easy, persuasive and useful tool for anticipating species distribution shifts under global change. Numerous studies have used only climate variables to predict future potential species range shifts and have omitted environmental factors important for determining species distribution. Here, we assessed the importance of the edaphic dimension in the niche‐space definition of Quercus pubescens and in future spatial projections under global change over the metropolitan French forest territory. We fitted two species distribution models (SDM) based on presence/absence data (111 013 plots), one calibrated from climate variables only (mean temperature of January and climatic water balance of July) and the other one from both climate and edaphic (soil pH inferred from plants) variables. Future predictions were conducted under two climate scenarios (PCM B2 and HadCM3 A2) and based on 100 simulations using a cellular automaton that accounted for seed dispersal distance, landscape barriers preventing migration and unsuitable land cover. Adding the edaphic dimension to the climate‐only SDM substantially improved the niche‐space definition of Q. pubescens, highlighting an increase in species tolerance in confronting climate constraints as the soil pH increased. Future predictions over the 21st century showed that disregarding the edaphic dimension in SDM led to an overestimation of the potential distribution area, an underestimation of the spatial fragmentation of this area, and prevented the identification of local refugia, leading to an underestimation of the northward shift capacity of Q. pubescens and its persistence in its current distribution area. Spatial discrepancies between climate‐only and climate‐plus‐edaphic models are strengthened when seed dispersal and forest fragmentation are accounted for in predicting a future species distribution area. These discrepancies highlight some imprecision in spatial predictions of potential distribution area of species under climate change scenarios and possibly wrong conclusions for conservation and management perspectives when climate‐only models are used.

A revision of the West African Hepsetus (Characiformes: Hepsetidae) with a description of Hepsetus akawo sp. nov. and a redescription of Hepsetus odoe (Bloch, 1794)

Within the genus Hepsetus, a new species from the eastern part of West Africa is described. Hepsetus akawo sp. nov. is mainly distinguished from Hepsetus odoe by a smaller number of lateral line scales [43–51 vs 50–60 (exceptionally 49)] and a shallower head depth [38.0–45.6 (mean 42.0) % head length vs 41.4–49.0 (44.6) % head length] (positively allometric). Hepsetus akawo sp. nov. differs mainly from the recently rehabilitated Hepsetus cuvieri by: a higher number of gill rakers (17–23 vs 8–13); and a lower number of scales between the dorsal fin and the lateral line (7½–9½ vs 10½–11½). Within West Africa, the distribution area of the new species is restricted to the Sassandra River (Ivory Coast) in the west up to the Cross River (Cameroon) in the east. The species is entirely allopatric with H. odoe, which has a far more restricted distribution than previously thought and occurs from the Senegal River (Senegal) in the west to the Cavally River (Ivory Coast) in the east.

Изучение ареала распространения видов рода Котовник (Nepeta L. ) в Азербайджане, их морфо-биологических особенностей

Изучение ареала распространения видов рода Котовник (Nepeta L. ) в Азербайджане, их морфо-биологических особенностей

Phylogenetic Relationship between Degree of Self-compatibility and Floral Traits in Lilium longiflorum Thunb. (Liliaceae)

Lilium longiflorum is endemic to the islands of the Ryukyu Archipelago in Japan and to the eastern seacoasts and satellite islands of the mainland of Taiwan. The species is an important ornamental plant, and is cultivated throughout the world. Lilium longiflorum has long been regarded as a self-incompatible species but the existence of selfing in some natural populations was suggested by isozyme analysis in a previous study. To confirm the occurrence of self-compatible individuals and to clarify the evolutionary shift of floral traits associated with degree of self-compatibility in L. longiflorum by comparative analysis, we used 17 populations of L. longiflorum, and two populations of L. formosanum, the genetically closest species of L. longiflorum, covering the entire species distribution. Artificial self-pollination revealed that not all L. longiflorum individuals are self-incompatible and there is substantial quantitative variation of self-incompatibility among L. longiflorum individuals and populations. Self-compatible dominant populations allopatrically and independently evolved at the periphery of the species distribution area, the northern Ryukyu Archipelago and Taiwan. Increasing degree of self-compatibility in L. longiflorum correlated with reduced corolla length, corolla width, corolla volume, and anther length for the Ryukyu Archipelago, in contrast to only reduced corolla width and volume for Taiwan. Approach between anther and stigma was not observed in any populations. Our data indicate that in the Ryukyu Archipelago increasing degree of self-compatibility evolved floral traits related to mating system evolution, to selfing, that does not depend on adjacency between anther and stigma position, but not in Taiwan.

The importance of defining the geographic distribution of species for conservation: The case of the Bearded Wood-Partridge

Delimitation of the distribution areas of species has fundamental implications for the understanding of biodiversity and for decision-making in conservation. This is illustrated by the case of the Bearded Wood-Partridge (Dendrortyx barbatus), which is endemic to Mexico and was classified as threatened by the IUCN. Recently the discovery of this species in new locations caused an increase in the known distribution area whereupon it was reclassified in a lower risk category. In our study, delimitation and comparison of the Bearded Wood-Partridge distribution area is carried out utilising five different methods: minimum convex polygon; areographic; cartographic; ecological niche modeling; and, “free hand”. A number of locality records are also used to demonstrate the chronological order of appearance. The results show that the size and shape of the distribution area of this species vary depending on the number of records and on their spatial and environmental location, as well as on the particular delimitation method used. However, ecological niche modeling provides the best results in terms of spatial and numerical sensitivity as well as lower values of omission and a moderate extent of predicted areas. We suggest that decisions related to species conservation (categories of risk, areas of endemism, etc.), particularly those species of high geographical restriction, should be contingent on the formalised delimitation of distribution areas based on ecological niche modeling methods.

Growth patterns and sensitivity to climate predict silver fir decline in the Spanish Pyrenees

Patterns in radial growth have often been used to predict forest decline since they are regarded as indicators of the tree responses to long-term stressors. However, the sensitivity of tree growth to climate, as a proxy of the trees’ adaptive capacity to short-term climatic stress, has received less attention. Here, we used retrospective tree-ring analyses to determine whether growth patterns and sensitivity to climate are related to Abies alba (silver fir) decline in the Spanish Pyrenees. We used regional climatic data to calculate normalised temperatures and drought indexes. Basal-area increment (BAI) was measured for declining (defoliation >50%) and non-declining (defoliation <50%) silver firs in four stands with contrasting decline levels. A dynamic factor analysis (DFA) was applied to test the hypothesis that declining and non-declining trees have experienced different long-term growth trends. Growth sensitivity to climate was computed as the average change in BAI per unit of change in a given climate variable. Declining trees showed a negative growth trend during the last 20 years. Trees with lower relative BAI and negative BAI trends showed stronger growth sensitivity to climate and higher defoliation than trees with the opposite characteristics. Our findings underscore the idea that long-term climatic warming seems to be a major driving factor of growth decline in Pyrenean silver fir forests. Ongoing growth reduction and enhanced growth sensitivity to climate may promote vegetation shifts in these declining forests located near the xeric edge of the species distribution area.

Fire regime shifts affect bird species distributions

AbstractAim Fire is a major driver of ecosystem structure and process, and shifts in fire regimes are implicated in the decline of many species. Shifting fire regimes have been documented around the world, and fire frequency and extent is predicted to increase in many areas because of changes in both climate and land management. Here, we evaluate how predicted increases in fire frequency are likely to impact on species distributions.Location The tropical savannas of northern Australia.Methods We developed distribution models for 44 bird species using the modelling algorithm Maxent. Our models incorporated bird locality records and environmental variables including climate, total fire frequency and the subset of fire frequency occurring late in the dry season. We investigated the effect of increasing total fire frequency and increasing fire late in the dry season, on species distributions by projecting species model algorithms onto scenarios of incrementally increased total fire frequency.Results The probability of presence for most species was higher when fire frequency late in the dry season was low. Species showed a mixed response to an overall increase in total fire frequency, with one‐third predicted to increase in distribution. However, almost all species (98%) showed a decrease in predicted range with increased late‐dry season fire, and species distribution area was generally negatively correlated with an increase in late‐dry season fire.Main conclusions Our study highlighted the array of responses of species to increasing fire frequency and suggested that increased fire frequency late in the dry season is detrimental to most savanna‐restricted bird species. The understanding of individual species’ preferences for particular fire frequencies is important for informed conservation planning.

Spatial distribution of phlebotomine sand flies in the Aydin Mountains and surroundings: the main focus of cutaneous leishmaniasis in western Turkey

An entomological survey was conducted to determine the spatial distribution of phlebotomine fauna and understand the effect of environmental factors. The entomological survey was carried out during 2006-2007 in a study area in the rural area of Aydin province, near the Kusadasi town where VL, CL, and canine leishmaniasis (CanL) are endemic. In 2006 and 2007, 132 locations were sampled using sticky traps mainly on embankments. Detailed environmental and meteorological information was also collected for each location. The results of entomological studies indicated that the probable vectors are Phlebotomus tobbi and P. neglectus for VL and CanL, and P. similis for CL in this western leishmaniasis focus. The data revealed a correlation between their presence and spatial variables such as altitude, sampling site location, and humidity. The distribution areas of probable vector species in this study area allowed the identification of risk levels, which may provide useful information to guide the leishmaniasis research in endemic regions.

Introduction et dispersion d'une espèce envahissante: le cas de l'ambroisie à feuilles d'armoise (Ambrosia artemisiifolia L.) en France

Ambrosia artemisiifolia L. (common ragweed) was accidentally introduced into France in the 1860s. Its single vector of introduction in Europe was red clover seeds (Trifolium pratense L.), probably coming from Pennsylvania, United States at the time. A. artemisiifolia was later introduced into France in many places and at different times. This species has no natural or effective seed dispersal mechanisms and the spread of this weed in the territory is ensured by human activities that carry the seeds and create disturbed environments favourable to its development. It is now established in the Rhône Valley and a number of different factors (cropping system evolution, climate change, etc.) contribute to increasing the distribution area of this allergenic species in France.

Influence of habitat on nest location and reproductive output of Montagu’s Harriers breeding in natural vegetation

We examined distribution and breeding success of semi-colonial Montagu’s Harriers (Circus pygargus) in relation to habitat in Castellon province (eastern Spain). Breeding areas used by harriers at a 1-km2 scale were characterised by having intermediate percentages of scrub cover, their nesting habitat, and also had intermediate coverage of herbaceous crops and non-irrigated orchards. Out of all habitat variables considered, only the percentage of herbaceous crops within 500 m from individual nests had a positive and significant effect on breeding output of the species, suggesting that this habitat may be efficiently used by harriers to forage. Breeding output was also related to laying date and number of breeding neighbours within 500 m around nests, with pairs laying later and having a higher number of breeding neighbours showing lower fledged brood sizes. Number of neighbours (but not laying date) was positively related to scrub cover within 500 m and to cover of herbaceous crops within 2,000 m. Conservation actions for Montagu’s Harrier in the study area should be aimed at preserving areas of scrub with nearby presence of herbaceous crops or natural grasslands. However, habitat improvement for semi-colonial species such as Montagu’s Harrier may not result in a change of species distribution area, and good habitat areas may remain unoccupied, as social factors like presence of conspecifics play an important role in breeding area selection for these species.

Growth of the fungus Geomyces pannorum under anaerobiosis

Fungi of the genus Geomyces are eurytopic organ� isms with a broad species distribution area. It is rea� sonable to study the adaptive capabilities of fungal cul� tures in members of the same microbial species exist� ing under drastically different environmental conditions. In our case, these are cryopegs of the Kolyma lowland and the soil of Central Russia. Cry� opegs are supercooled saturated salt solutions charac� terized by a constant temperature (from –10 to ⎯15°C) and total mineralization of 60–300 g/l [1, 2]. Thus, water remains unfrozen and is under anaerobic conditions (Eh from –56 to –240 mV) [3]. The meta� bolic status of mycelial fungi under deep anaerobiosis combined with the low temperature and high salinity of the environment remains unknown; it is, however, highly important to determine the mechanism respon� sible for the preservation of the viability of fungal organisms under such extreme conditions. The goal of the present work was investigation of the metabolic capabilities of two Geomyces pannorum strains, specifically, of their ability to grow and form the fermentation products in the absence of oxygen in the media with different redox potentials (Eh). The objects of research were the strain VKM FW�2241 iso� lated from cryopeg water in permafrost deposits of the Arctic [4] and the strain VKM F�3808 isolated from the hair of bank vole Cletrionomys glareolus (Tver oblast, Russia). The partial 18S rRNA gene sequences of both strains are deposited in GenBank under acces� sion numbers AY873966 and AY873968, respectively. The strains under study were grown on a modified Czapek medium [5]. In the experiments with different reducing agents, ammonium sulfate was added to the

Genetic variability and differentiation in the Polish common hamster ( Cricetus cricetus L.): Genetic consequences of agricultural habitat fragmentation

The common hamster is endangered in Europe due to changes in agricultural practice, industrialization, and direct persecution. In Poland, two main areas of the current species distribution have become separated. Moreover, theoretical possibilities of the gene flow have been further complicated by the presence of two ancient phylogeographic lineages. To describe the differentiation of the populations and levels of gene flow in this complex pattern, we examined the current genetic variability using a set of 17 nuclear DNA microsatellites in 195 hamsters representing 12 sampling sites. The levels of genetic diversity are fairly high within phylogeographic lineages, but most of the variation is partitioned between populations. The common hamster populations probably function in a metapopulation structure and the connectivity of habitats is crucial for diversity preservation. Presently the possibilities of the gene flow are low or absent, which already becomes evident in lowered diversity measures of one lineage. Although the common hamster populations are genetically resilient to fluctuations in numbers, the fragmentation of agricultural habitats and isolation of suitable patches directly endangers the species.

Morphological divergence of North-European nine-spined sticklebacks (Pungitius pungitius): signatures of parallel evolution

Parallel evolution is characterised by repeated, independent occurrences of similar phenotypes in a given habitat type, in different parts of the species distribution area. We studied body shape and body armour divergence between five marine, four lake, and ten pond populations of nine-spined sticklebacks [Pungitius pungitius (Linnaeus, 1758)] in Fennoscandia. We hypothesized that marine and lake populations (large water bodies, diverse fish fauna) would be similar, whereas sticklebacks in isolated ponds (small water bodies, simple fish fauna) would be divergent. We found that pond fish had deeper bodies, shorter caudal peduncles, and less body armour (viz. shorter/absent pelvic spines, reduced/absent pelvic girdle, and reduced number of lateral plates) than marine fish. Lake fish were intermediate, but more similar to marine than to pond fish. Results of our common garden experiment concurred with these patterns, suggesting a genetic basis for the observed divergence. We also found large variation among populations within habitat types, indicating that environmental variables other than those related to gross habitat characteristics might also influence nine-spined stickleback morphology. Apart from suggesting parallel evolution of morphological characteristics of nine-spined sticklebacks in different habitats, the results also show a number of similarities to the evolution of three-spined stickleback (Gasterosteus aculeatus Linnaeus, 1758) morphology. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101, 403–416.