Open Ecology Journal最新文献

{"title":"Introduced Alien Plant Species in the Neotropics: the Panama Case","authors":"O. Lopez","doi":"10.2174/1874213001205010084","DOIUrl":"https://doi.org/10.2174/1874213001205010084","url":null,"abstract":"Non-insular tropical biomes appear relatively resistant to invasive alien species (IAS). While some argue fewer IAS in continental tropical communities is the result of the complexity of species-rich communities (e.g., Elton's biological resistance hypothesis), others suggest lack of IAS might reflect fewer invasion opportunities, which could change with time. In effect, deforestation may lead to the simplification of tropical habitats, thus reducing biological resistance. Little is known about the current status of alien plants species, factors contributing to their spread and IAS in non-insular tropical systems. Here I report on the status of alien plant species in relation to area, number of native and endemics species, population, forest cover and cultivated area across provinces of Panama. Alien plant species comprise nearly 4 percent of the flora and was positively correlated with the number of native plant species (r = 0.84, P < 0.001) and while this pattern runs counter to Elton's premise, it is consistent with other landscape-scale studies. In Panama, the number of alien plant species is explained by population density (r= 0.91, P < 0.01) and potentially linked to disturbance, albeit coarsely, as the proportion of aliens negatively correlates with forest cover (r = 0.69, P < 0.05). Thus, despite high diversity, these results portray disturbed tropical forests becoming dotted with introduced alien species. While few species seem to become invasive in the continental tropics, rapid land use change could promote the success of IAS representing serious consequences for tropical countries' economies and biodiversity.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"34 1","pages":"84-89"},"PeriodicalIF":0.0,"publicationDate":"2012-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68054917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"American-Australian Scientific Expedition to Arnhem Land (1948): ItsLong-Range Impact","authors":"R. Specht","doi":"10.2174/1874213001205010053","DOIUrl":"https://doi.org/10.2174/1874213001205010053","url":null,"abstract":"The American-Australian Scientific Expedition to Arnhem Land in the Northern Territory of Australia was sponsored by the National Geographic Society and the Smithsonian Institution in the United States and the Commonwealth Government of Australia. During 1948, two anthropologists, an archaeologist, four biological scientists and three health and nutrition experts, with two photographers and three support staff, spent eight months studying the ecology of this infertile, monsoonal landscape to learn how the present-day Aborigines who had arrived between 3500 and 5000 years ago displacing the first hunter-gatherers, the Mimi, who arrived some 53,000 to 60,000 years before were able to survive throughout the year. The Gondwanan origins of the heathy flora of the sandstones, the grassy eucalypt forests and woodlands on the lateritic earths, the monsoonal rainforests, the wetland and coastal plant communities -with vegetation structures similar to those in southern Australia inspired long-term research on the physico-chemical processes (aerodynamic, water relations and mineral nutrition) that determine the structure, growth and biodiversity of plant formations throughout Australia. The cooperative research that was fostered between the United States and Australia during the 1948 Arnhem Land Expedition has continued over the last sixty years in the Fulbright Program, the UNESCO Arid Zone Research Programme, the International Biological Programme (especially in the Arid Zone Biome, the Grassland Biome, the Mediterranean-climate Biome, the Heathland Biome, the Wet-Dry Tropical Biome and Rainforest Biome Programs), the International Union for the Conservation of Nature and, since the 1990s, the International Geosphere-Biosphere Programme to tackle Global Warming.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"93 1","pages":"53-83"},"PeriodicalIF":0.0,"publicationDate":"2012-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68054909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genetically Engineered Antifungal Wheat has no Detrimental Effects on the Key Soil Species Lumbricus terrestris","authors":"A. Lindfeld, W. Nentwig","doi":"10.2174/1874213001205010045","DOIUrl":"https://doi.org/10.2174/1874213001205010045","url":null,"abstract":"Since the first introduction of genetically engineered (GE) plants, one of the major concerns has been their potential effects on non-target organisms and ecosystem services. We focused in this study on the earthworm species Lumbricus terrestris as important ecosystem engineer and studied its performance when feeding on GE antifungal wheat. We compared litter consumption, weight change and mortality of individuals feeding on GE wheat with either specific resistance against powdery mildew (Blumeria graminis) or unspecific resistance against fungi via chitinase and glucanase expression with individuals feeding on non-GE wheat or other conventional crops. We did not find detrimental direct or indirect effects of GE wheat on L. terrestris and overall L. terrrestris tended to cope even better with GE wheat varieties. Concluding from our experiment the transgene products do not harm the soil key species L. terrestris and ecosystem services like decomposition, organic matter turnover and nutrient cycling are unlikely to be affected detrimentally.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"5 1","pages":"45-52"},"PeriodicalIF":0.0,"publicationDate":"2012-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68054894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Line Transects by Design: The Influence of Study Design, Spatial Distribution and Density of Objects on Estimates of Abundance","authors":"S. Nomani, M. Oli, R. Carthy","doi":"10.2174/1874213001205010025","DOIUrl":"https://doi.org/10.2174/1874213001205010025","url":null,"abstract":"The line transect distance sampling method provides unbiased estimates of abundance when organisms are distributed randomly or line transects are laid out randomly, sample sizes are large and other assumptions of the method are met; such, however, is rarely the case in real life. We conducted a simulation study to investigate how spatial distribution and density of objects, and total length, layout and number of transects influence bias, precision, and accuracy of estimates of abundance obtained by distance sampling along line transects. Overall, density estimated using the distance sampling method was within 4.9% of the true density, but it varied substantially depending upon spatial distribution of objects. Of the three spatial distribution patterns considered, estimates of density were least biased, and most precise and accurate when objects were distributed randomly; they were most biased, and least precise and accurate when objects followed a clumped distribution. The estimated bias (% difference between true density and estimated density) for clumped, random and uniform distribution was 13.1%, -0.4%, and 2.1%, respectively; precision (% coefficient of variation, CV( ˆ D )) was 13.7%, 9.1%, and 9.2%; and accuracy (root mean-squared error, RMSE) was 27.9%, 7.4%, and 11.7% for clumped, random, and uniform distribution, respectively. Increasing total transect length and using several short transects (as opposed to few long transects) generally reduced bias, and increased accuracy and precision of estimates of abundance. A systematic layout of transects worked as well as, or better than, random layout, except when objects were distributed uniformly in space. This study advances the utility of the line transect method by providing information both on how study design affects accuracy and precision of abundance estimates, and how it can be improved when assumptions of the method are not strictly met based on a priori knowledge of the spatial distribution and presumed density of the target organism through appropriate changes in the study design.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"5 1","pages":"25-44"},"PeriodicalIF":0.0,"publicationDate":"2012-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68054853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Black Bears, Palms, and Giant Palm Weevils: An Intraguild Mutualism","authors":"D. Tedder, J. Cox, P. Crowley, D. Maehr","doi":"10.2174/1874213001205010018","DOIUrl":"https://doi.org/10.2174/1874213001205010018","url":null,"abstract":"In peninsular Florida, USA, the palm-feeding guild is dominated by the black bear (Ursus americanus floridanus, Pallas) and the giant palm weevil (Rhynchophorus cruentatus, Fabricius). Bears damage palms by consuming their hearts, allowing the weevil to reproduce within the exposed palm tissue. The giant palm weevil reproductively benefits from bear-damaged palms, and bears gain a valuable fat-rich food supply from consuming the insects, an apparent intraguild mutualism. We analyzed a natural experiment across widely distributed sites based on presence or absence of bear populations to test the hypothesis that the presence of bears increases the abundance of the giant palm weevil. Results support the hypothesis; data also show greater attraction of females than males to pheromone traps and indicate a predominance of activity by the insect during the day and at lower summer temperatures. This interaction closely resembles one previously documented involving indigenous humans in Amazonia.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"5 1","pages":"18-24"},"PeriodicalIF":0.0,"publicationDate":"2012-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68054778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamics of an Insularized and Compressed Impala Population: Rainfall, Temperature and Density Influences","authors":"J. Ogutu, H. Piepho, E. Kanga","doi":"10.2174/1874213001205010001","DOIUrl":"https://doi.org/10.2174/1874213001205010001","url":null,"abstract":"Understanding the relative contributions of different life history stages to changes in population abundance is basic to understanding population dynamics and effective management and conservation of large herbivores. We examined temporal variation in natality, recruitment and mortality rates and sex ratio in a compressed and insularized impala population monitored daily for 211 months (17.6 years), spanning June 1994-December 2011. We related the rates to contemporaneous variation in immediate and cumulative past rainfall, temperature and prior abundance. Over the course of this 17.6-year period, the population size fluctuated between 22 and 52 individuals. A total of 213 births, mortality of 96 lambs, 33 males and 58 females; recruitment of 55 juveniles into the female category and 40 juveniles into the male category were recorded. Natural mortality averaged 2.3% of the population annually with lambs contributing 52.3%, males 26.6% and females 21.2%. Lamb mortality was highest in dry months, implicating food scarcity, but female mortality peaked in the wettest months and in hot, wet seasons, suggesting increased susceptibility to diseases and pathogens in hot, damp weather conditions. Male, female and overall population mortality rates were positively correlated with prior abundance, implicating negative density feedbacks on population growth. Births were aseasonal and were surprisingly negatively correlated with rainfall around the time of conception and during wet phases of a regional 5-year rainfall cycle. This implies, quite surprisingly, that high rainfall depressed reproductive success in impalas. Juvenile recruitment increased with increasing 5-month running mean of monthly rainfall but declined (i) at excessively high values of annual rainfall, (ii) with increasing prior density and (iii) in hot, dry seasons. This implicates heightened competition for limiting resources and nutritional stress at high density, increased vulnerability to diseases and pathogens at high rainfall and adverse consequences of habitat desiccation and reduced activity levels at high ambient temperatures.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"5 1","pages":"1-17"},"PeriodicalIF":0.0,"publicationDate":"2012-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68054762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Meta-Analysis of the Global Distribution Pattern of Condensed Tanninsin Tree Leaves","authors":"Masayuki Ushio, Jonathan M Adams","doi":"10.2174/1874213001104010018","DOIUrl":"https://doi.org/10.2174/1874213001104010018","url":null,"abstract":"Condensed tannins (CT's) are a dominant class of plant secondary metabolites that play important roles in regulating ecosystem processes such as herbivory, decomposition, and nutrient cycling. However, the factors shaping the global distribution pattern of the abundance of CT's in tree leaves are still poorly understood. The purpose of this study was to assess the global distribution pattern of CT abundance in tree leaves in order to examine the effects of climatic parameters (air temperature and precipitation) and latitude as well as the effects of methodologies used for the measurement of CT concentration (extract solutions and standard substance). Through a database search, we collected 805 individual values of CT concentration in tree leaves from 72 study sites, which were reported in 26 individual studies as well as mean annual temperature, annual precipitation, and latitude. We also collected the information of extract solution and standard substance if available. We found that mean annual temperature positively correlated with the foliar CT abundance. On the other hand, annual precipitation and latitude did not have significant influences on CT abundance. We did not find significant effects of the extract solution and standard substance on the CT abundance, neither. A higher allocation of carbon to CT's may be advantageous in warmer regions, where the potential herbivore pressure may be relatively higher than that in cooler regions; however, this hypothesis could not be directly tested in this study. Our finding that foliar CT abundance is significantly associated with mean annual temperature supports the 'classical' picture of the stronger plant defenses in warmer climates. A comprehensive empirical comparison using standardized methods is still required to improve our understanding of CT abundance in tree leaves and the mechanism of ecosystem processes.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"4 1","pages":"18-23"},"PeriodicalIF":0.0,"publicationDate":"2011-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68054713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measuring Diversity in Plant Communities with Mosaic Spatial Patterns: Danish Coastal Dunes","authors":"C. Damgaard, B. Nygaard, K. E. Nielsen, R. Ejrnæs","doi":"10.2174/1874213001104010010","DOIUrl":"https://doi.org/10.2174/1874213001104010010","url":null,"abstract":"Hierarchical pin-point data from 5316 plots from 73 Danish coastal dune sites were analysed in order to describe the species diversity in dune plant communities on a regional scale. Due to the mosaic spatial pattern of the dune communities, it was decided to describe the spatial structure of each plant species in each community using a vegetation type conditioned approach, where the hierarchical pin-point data were fitted to a zero-inflated generalised binomial distribution. Furthermore, summary statistics of the Lorenz curve of the regional estimates of species abundance are suggested in order to describe inequality of species abundance and to test for a possible log-normal species abundance distribution. The mean plant cover and the degree of spatial aggregation were estimated for all species found in six dune communities. Most plant species had a significant aggregated spatial distribution, and there was a significant positive correlation between the mean plant cover and the degree of aggregation. Species abundance did not depart from a log- normal species abundance distribution in any of the investigated dune community types. A vegetation type conditioned approach was found to be appropriate for analysing vegetation data of mosaic vegetation at a regional scale, and it is expected that the introduced method of measuring the direction of the deviation from a log-normal distribution will be important for interpreting the underlying cause of observed departures from log-normally distributed abundance curves.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"4 1","pages":"10-17"},"PeriodicalIF":0.0,"publicationDate":"2011-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68054703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temporal Changes in Morphological Traits in a Population of Echinacea pallida in the Tall Grass Prairie Preserve, Oklahoma","authors":"J. Arévalo, Adam K. Ryburn, Soni Jaiswal","doi":"10.2174/1874213001104010001","DOIUrl":"https://doi.org/10.2174/1874213001104010001","url":null,"abstract":"We analyzed the structure and spatial temporal changes of a population of Echinacea pallida in the Tall Grass Prairie Preserve of Oklahoma. Plants were classified into different categories based on total leaf length and transition probabilities for three periods (1997-1998, 1998-1999, 1999-2000) and were used to determine temporal changes. The analysis of transition probabilities among different size classes for the three periods allowed us to discriminate the transition probabilities matrices. A univariate spatial analysis of individuals showed significant aggregation for most distances greater than 40 cm; from 0 to 40 cm the spatial distribution of stems did not differ (p>0.05) from a random distribution. Aggregation increased from year 1 to year 4 of the study period, which seems to be related to an increase in density.Although we did not have a control site, results for both years with previous burning strongly suggest the effect of fire in the population dynamic.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"4 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2011-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68054666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interaction Milieu Explains Performance of Species in Simple Food Webs along an Environmental Gradient","authors":"J. Ellers, A. T. Dias, M. Berg","doi":"10.2174/1874213001003040012","DOIUrl":"https://doi.org/10.2174/1874213001003040012","url":null,"abstract":"Species interact with each other in a complex network of relationships that can be modeled as an interaction milieu, i.e. a biotic background with which the species interacts. The interaction milieu is given by the frequency distribution of traits that are important to a given interaction; hence this approach provides a direct link between organism performance, abiotic environmental conditions and interspecific interactions. In this study, we investigate how performance of component species is affected by the interaction milieu along an environmental gradient. We specifically addressed two questions: 1) can the interaction milieu shift species performance away from the niche optimum?, and 2) do species have a higher invasive potential if they have divergent trait values compared to the interaction milieu? We developed a model where a target species showing a given performance response curve to an environmental gradient, i.e., generalist or specialist, interacts with predators and competitors. The predictions of the model were compared with empirical findings on the abundance patterns of species along a salinity gradient in a green beach ecosystem. Green beaches are characterized by their strong gradients and spatial variability in abiotic factors, and their relatively simple food web consisting of Collembola species and their spider predators. First, our results showed that interaction milieu can displace species from their fundamental niche optimum. This led to abundance patterns that cannot be predicted by species performance response curves alone, emphasizing the importance to include ecological interactions. Second, species failed to invade their preferred part of the gradient if predators or competitors shared the target species' preference. Future studies should explore if the concept of interaction milieu can be generalized across trophic levels, and search for traits that are important on deciding the outcome of ecological interactions. Furthermore, the identification of the relevant response traits and their frequency distribution, in combination with trait plasticity of species in interaction milieus might be a step forward to link evolutionary principles to ecological networks, and vice versa.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"3 1","pages":"12-21"},"PeriodicalIF":0.0,"publicationDate":"2011-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68054654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}