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1.
As climate is an important driver of vegetation distribution, climate change represents an important challenge to forestry. We (1) identify prevailing bioclimatic conditions for 49 relevant forest species in Portugal and (2) assess future shifts under climate change scenarios. We compute two bioclimatic indices (aridity and thermicity) and a new composite index, at ~1 km spatial resolution, and overlap with the species’ current ranges. Locations are based on a digital inventory, while climate parameters for both recent-past (1950–2000) and future climates (2041–2060), under RCP4.5 and RCP8.5, are provided by a multi-model ensemble of climate simulations. Results for future scenarios highlight an overall warming and drying trend. Supramediterranean and mesomediterranean climates will be significantly reduced, while thermomediterranean climates will dramatically increase, from their almost absence in current conditions to an area coverage of ~54 % in 2041–2060 for RCP8.5. There is also a clear shift from hyper-humid and humid to sub-humid and from the latter to semi-arid climates (area coverage of ~13 % in 2041–2060 for RCP8.5). Lower thermomediterranean sub-humid to semi-arid zones will cover the southern half of Portugal. These projections identify the most vulnerable (e.g. Betula pubescens, Quercus pyrenaica and Castanea sativa) and the most adapted (e.g. Quercus suber, Q. rotundifolia, Ceratonia siliqua, Pinus pinea, Quercus coccifera) species in future climates. Current bioclimatic zones associated with Eucalyptus globulus and Pinus pinaster, economically relevant species, will be moderately reduced and relocated. Possible adaptation measures are discussed to improve forest resilience to climate change, while maintaining its economic and environmental benefits.  相似文献   

2.
Experimental studies of interactions between two amphipod species (Gmelinoides fasciatus and Gammarus lacustris) showed that predation is the basic mechanism accounting for their mutual exclusion in nature. Mortality from predation among similar-sized specimens of both species at an equal abundance ratio was similar (24–25% in G. lacustris and 27–30% in G. fasciatus). The displacement of G. lacustris by G. fasciatus was observed when the latter was dominant. Adult G. fasciatus and G. lacustris successfully preyed on juveniles of their competitors and did not differ significantly in daily food consumption as a percentage of body weight: 6–24% at a fresh body weight of 18–24 mg in both species. The potential for rapid population growth under new conditions contributed to the success of the invasive Baikal species G. fasciatus in displacing G. lacustris from many water bodies of Russia.  相似文献   

3.
Although the coastal salt marshes of Arabian Gulf have been altered extensively by human development activities, there is a paucity of data describing changes in the distribution and abundance of native coastal plant communities. The main objectives of this study are to determine vegetation condition, size structure, and conservation status of Nitraria retusa, a medicinal and salt-tolerant shrub, in disturbed and non-disturbed coastal salt marshes of Kuwait. Size measurements of Nitraria shrubs and nabkas, which are mounds of sediment developed around shrubs, were carried out in 50 quadrats (20 × 20 m2), randomly selected inside and outside Sabah Al-Ahmad Natural Reserve. Species richness and soil properties of nabkas and interspaces, the open areas between the nabkas, were also measured. The results revealed that nabkas of Nitraria in non-disturbed sites are more stable and rich in plant diversity than those in disturbed sites. Mean height and mean canopy diameter of Nitraria shrubs, total plant cover, and species richness are significantly higher in non-disturbed sites than disturbed sites, which indicate the positive influences of conservation for long term on vegetation structure and species richness. The results of soil analyses indicate the important role of nabkas in providing refuges for plant life and species diversity. The present study indicates that more than 50 % of the N. retusa community has been lost during the last few decades. Therefore, N. retusa should be considered an endangered species in Kuwait. The reduction in vegetation cover, a decline in species richness, and the overall degradation of salt marshes are attributed to human development activities along the coast of Kuwait. Effective conservation actions for threatened species in degraded coastal salt marshes of this region include establishment of protective enclosures, prohibitions on development that adversely affects native plant communities, and the planting native salt-tolerant shrubs to facilitate regeneration.  相似文献   

4.
Basic climatic parameters (annual average air temperature and annual amount of precipitation) over 12–25 years have been analyzed with regard to their values corresponding to different levels of abundance in three species of forest voles: Clethrionomys glareolus (in 11 areas of the species range), Cl. rutilus, and Cl. rufocanus (in three areas each). The results show that the abundance of all these species correlates significantly with fluctuations of annual average temperature, with the correlation being negative in Cl. glareolus and Cl. rufocanus but positive in Cl. rutilus. In addition, the abundance of Cl. rufocanus shows a significant correlation with annual precipitation. Voles inhabiting different geographic regions may reach high abundance under different conditions. As for the species range as a whole, however, Cl. glareolus is more ecologically flexible than the other two voles. This species is also more warmth- and moisture-loving, while Cl. rufocanus is more cold-loving and xerophilous, with Cl. rutilus occupying an intermediate position between them. Clethrionomys rutilus is most temperature-dependent and stenothermic among them, whereas Cl. glareolus is indifferent to the factors studied.  相似文献   

5.
The taxonomic diversity of the Hirudinea fauna and its dependence on the ecological conditions in the Bukhtarma Reservoir (Eastern Kazakhstan) have been studied. The morphological analysis has shown that these leeches belong to two orders and three families: Rhynchobdellida (families Glossiphoniidae and Piscicolidae) and Arhynchobdellida (family Erpobdellidae). On the whole, eight leech species from five genera (Alboglossiphonia, Helobdella, Theromyzon, Piscicola, and Erpobdella) have been identified. Among them, there are three glossiphoniid species (A. heteroclite, H. stagnalis, and T. tessulatum), two species of piscicolids (Piscicola geometra and Piscicola sp.), and three species of predatory leeches (E. octoculata, E. vilnensis, and Erpobdella sp.). Possible effects of hydrochemical parameters of the aquatic environment on the species diversity have been analyzed. Correlation has been revealed between the abundance of species and the physical and chemical characteristics of the environment.  相似文献   

6.
Returning farmland to forests is important for the protection of ecological values. Eucommia ulmoides is considered to be a suitable species for reforestation in the hilly red soil region of southern China. The objective of this study was to investigate the relationship between the water supply and demand of an E. ulmoides plantation to provide insights into the feasibility of large-scale planting for ecological restoration and forest management activities in the hilly red soil region of southern China. With the measured precipitation, surface runoff and interflow and actual evapotranspiration (ETc) estimated by the modified P–M model, soil water storage (SWS) was estimated based on the water balance equation. Monthly variations of SWS were then compared with in situ measured SWS. The results showed that the estimated mean monthly water losses (the sum of the surface runoff, interflow and ETc) were 139.8 mm in a wet year and 120.0 mm in a dry year, while the measured mean monthly water input values (net precipitation) were 131.2 mm in a wet year and 70.8 mm in a dry year. Net soil water storage (ΔSWS) was negative in each month of the growing season in a dry year, but the soil water deficit was replenished during the following season. The model performance showed that the modified P–M model can be adapted to estimate the soil water storage in other forest catchments where no adequate in situ data are available. As a result of estimating the water balance and observing soil water storage in two different hydrological years, E. ulmoides is recommended as a suitable forest rehabilitation species in the study area, and a suitable plant region has been defined by the GIS technique based on the water balance model.  相似文献   

7.
Future climate change may lead to a substantial loss of biodiversity, particularly affecting mountain regions, including the Alps. Range-size reduction in high mountain plant species is predicted to be more pronounced for endemic species. Investigating the broad temporal spectrum of range shifts is important for the conservation of biodiversity, since learning how species responded to climate change in the past provides useful insights on how they might react to warming trends in the present and future. Using species distribution models and an ensemble forecasting approach, we explored how the distribution of Berardia subacaulis, a monospecific genus endemic of the south-west Alps, may be affected by past and future projected climate change. During the last interglacial, the habitat suitability of Berardia was lower than present and a progressive increase was observed from the last glacial maximum until now. In the future, Berardia appears to lose more than 80 % of its range, becoming endangered by 2050. Our results suggest that Berardia probably survived past warmer periods in situ, expanding its distributional range during cooler periods. The severe future range contraction predicted for Berardia reflects similar results for other endemic species. As Berardia represents an interesting model species to evaluate the effects of climate warming on range size and shifts, demographic and precise range monitoring may be undertaken on this species.  相似文献   

8.
In 2010, the global burden of foodborne diseases was 33 million Disability-adjusted life years, and 40 % of this burden was for children under 5 years old (Havelaar et al. 2015). Our study site was informal public markets within Mzuzu, Malawi, visited between September and December 2015, during the dry season. From these markets, fresh vegetables, leafy greens (n = 85), tomato (n = 85), and green pepper (n = 35) were analyzed for Escherichia coli. The prevalence of E. coli was highest on leafy greens; it was found in 74 (87 %) of the 85 samples. The prevalence of E. coli in green peppers was found in 2 (6 %) of the 35 samples. The prevalence of E. coli was lowest on tomatoes; it was found in only 1 (1 %) of the 85 samples. The lack of adequate water and sanitation infrastructure in market areas may be contributing to the bacteriological contamination of fresh produce. Providing venders with free access to market area toilets containing hand-washing facilities with soap and wash water with a chlorine solution may reduce bacterial contamination of fresh produce. Universal and sustainable access to water and sanitation services must include informal public market areas to reduce diarrheal diseases transmitted through food within Sub-Saharan Africa countries.  相似文献   

9.
The results of long-term observations (1983–2013) on the dates of arrival of migratory birds to the Ilmen State Reserve are presented. Based on their analysis, it is conclude that (1) there is no significant positive trend of spring temperatures in the territory of the reserve, and (2) an earlier arrival of the majority of bird species is not observed, unlike in Europe. The arrival has shifted to earlier dates in the Common Chaffinch (Fringilla coelebs), White Wagtail (Motacilla alba), and Black Kite (Milvus migrans). On the other hand, the arrival of the Tree Pipit (Anthus trivialis) is observed later than usual. Multiple regression analysis has shown that the arrival dates of most species that nest in the reserve are determined by the temperature regime of spring months in their nesting area.  相似文献   

10.
We tried to model habitat suitability of two prey and predator species including wild sheep (Ovis orientalis) and wolf (Canis lupus) in Varjin protected area located in northern east of Tehran using a presence only method, maximum entropy (MaxEnt). Totally 11 environmental variables were measured in the species presence points which can be classified in three groups including topographical, vegetation and distal variables. Resulted maps indicated that habitat variables such as slope (ranging from 35 to 40 percent) and elevation (lower than 1700 meters above sea level) are both institute those factors which mostly affect studied prey and predator habitat use. Our results regarding prey and predator geographical range of used habitat indicated that wolves cover most area than wild sheep which show more dispersed habitat resources for the prey species. ENMTools test revealed that wolf’s niche breadth is more than twice as much as wild sheep’s. Wild sheep in Varjin protected area has a relatively narrow geographical extent and shows a tendency to marginal habitats while wolves cover obviously more areas which denotes its high mobility and low dependency to specific habitats.  相似文献   

11.
According to observed twentieth century temperature trends and twenty-first century climate model projections, the region that encompasses the eastern Mediterranean and the Middle East (EMME) is identified as a climate change hot spot. We extend previous studies by a comprehensive climatology of heat waves in the EMME based on regional climate model simulations for the recent past and the end of the twenty-first century. A percentile-based definition of heat waves is used to account for local climatic conditions. Spatial patterns of several heat wave properties are assessed and associated with atmospheric circulation regimes over specific locations. To cover a range of possible future climates, we use three SRES emission scenarios. According to our results, all indices that characterize heat wave severity will strongly increase compared with the control period of 1961–1990. The northern part of the EMME could be exposed to increased heat wave amplitudes by 6–10 °C, and the southern part may experience 2–3 months more combined hot days and tropical nights. Heat wave peak temperatures will be higher due to the overall mean warming as well as stronger summer anticyclonic conditions. The projected changes will affect human health and the environment in multiple ways and call for impact studies to support the development of adaptation strategies.  相似文献   

12.
The amino acid spectrum of blood plasma in three bat species (Myotis dasycneme, Pipistrellus nathusii, Vespertilio murinus) inhabiting the Urals has been studied for the first time. The bats were trapped in the zone of their high abundance in Chelyabinsk oblast (2013–2014). Free amino acids were determined by liquid ion exchange chromatography (a total of 384 determinations). It has been shown that the plasma amino acid spectrum consists of 22 amino acids in subadult bats of all three species, but there are species-specific differences in their concentrations. The total amino-acid pool concentration in migratory P. nathusii and V. murinus exceeds that in resident M. dasycneme by factors of 2.9 and 1.8, respectively. Migratory species are characterized by a high concentration of plasma arginine: it is six times higher in V. murinus than in M. dasycneme, and in P. nathusii arginine accounts for 25.4% of the amino acid pool. The group of glucogenic amino acids is prevalent in the blood plasma of migratory species (75% in V. murinus and 79% in P. nathusii), while in M. dasycneme the total proportion of lysine, glycine, and glutamic acid is 2.3 times lower than in P. nathusii and 1.7 lower than in V. murinus (p < 0.05). These results provide evidence for significant differences in the contents of free blood plasma amino acids between migratory and resident bat species.  相似文献   

13.
Monitoring and detecting trends of climatic variables like rainfall and temperature are essential for agricultural developments in the context of climate change. The present study has detected trends in annual and cropping seasonal rainfall and temperature data for the period of 1961–2011 using Mann–Kendall (MK) test, Spearman’s rho (SR) test and modified Mann–Kendall test that has been applied to the significant lag-1 serial correlated time series data, and slope has been estimated using Sen’s Slope estimator for twelve meteorological stations located in the western part of Bangladesh covering about 41 % of the country. Almost 71 % trends explored by MK test in annual rainfall are statistically insignificant, and SR test also complies it. The spatial distribution of rainfall trend shows insignificant positive trends in major part of the area. Significant positive trends both by MK test and by SR test at 95 % confidence levels are observed at rates of 8.56, 11.15 and 13.66 mm/year at Dinajpur, Rangpur and Khepupara stations, respectively, and the Kharif season rainfall of these stations also shows significant increasing trends except Dinajpur. On the other hand, significant decreasing trends in annual rainfall are found at Bhola (?11.67 mm/year) and Rajshahi (?5.951 mm/year) stations and decreasing trends in rainfall dominated the Pre-Kharif season over the area. But, 83.33 % of the stations show rising trends in annual mean temperature with significant positive trends (as observed by both MK test and SR test) at Rangpur, Bogra, Faridpur, Jessore and Bhola stations where the rate of changes vary from 0.013 °C/year at Faridpur to 0.08 °C/year at Bhola. Most of the trends in Rabi and Pre-Kharif seasons of mean temperatures are not statistically significant. However, all stations except Barisal show significant rising trends in temperature in Kharif season. To cope with this changing pattern of rainfall and temperature, effective adaptation strategies should be taken to keep up the agricultural production that is related to livelihood of the most people and to ensure the country’s food security.  相似文献   

14.
Methods of geometric morphometrics and population phenogenetics have been used to evaluate morphogenetic rearrangements in two sympatric species of Myodes voles (M. glareolus Schreb. 1780 and M. rutilus Pall. 1779) from syntopic populations recovering after exposure to local “ecological vacuum” created as a result of rodent extermination in a natural focus of hemorrhagic fever in the southern taiga subzone of the Udmurt Republic. The model used in the study simulates the situation that arises upon nonselective elimination of rodent populations and communities in spring and their subsequent recovery. Analysis of variation in the size and shape of the mandible and in a complex of 30 nonmetric cranial characters has revealed similar (parallel) and species-specific morphogenetic and epigenetic changes occurring during the recovery of local rodent community. Species-specific differences in the pattern of change in the parameter characterizing within-group morphological disparity in the mandible shape (MNND) have been revealed between the dominant species (M. glareolus) and the subdominant species competing with it for territory (M. rutilus). Different reactions of close Myodes species in the course of filling the ecological vacuum are considered as a result of reduction in the level of competition for the subdominant species and a compensatory increase of morphological disparity in the dominant species under conditions of low density and incomplete composition of the community, in accordance with Chernov’s (2005) ecological compensation principle.  相似文献   

15.
Specific ecological features of trees (Chosenia arbutifolia and Betula lanata) and shrubs (Pinus pumila and Duschekia fruticosa) at the northern limit of their distribution are compared. New biomorphological adaptations of these species under extreme conditions are described.  相似文献   

16.
Magnitudes of land cover changes nowadays can be assessed properly, but their driving forces are subject to many discussions. Next to the accepted role of human influence, the impact of natural climate variability is often neglected. In this paper, the impact of rainfall variability on land cover changes (LCC) is investigated for the western escarpment of the Raya Graben along the northern Ethiopian Rift Valley. First, LCC between 2000 and 2014 were analysed at specific time steps using Landsat imagery. Based on the obtained LCC maps, the link was set with rainfall variability, obtained by means of the satellite-derived rainfall estimates (RFEs) from NOAA-CPC. After a correction by the incorporation of local meteorological station data, these estimates prove to be good estimators for the actual amount of precipitation (ρ RFE1.0 = 0.85, p = 0.00, n = 126; ρ RFE2.0 = 0.76, p = 0.00, n = 934). By performing several linear regression analyses, a significant positive relationship between the precipitation parameter DIFF 5Y (i.e. the at-RFE pixel scale difference in five-year average annual precipitation for the two periods preceding the land cover maps) and the changes in the woody vegetation cover was found (standardised regression coefficient β = 0.23, p = 0.02, n = 108). Despite the dominance of direct human impact, further greening of the study area can be expected for the future concomitantly to a wetter climate, if all other factors remain constant.  相似文献   

17.
Eomecon chionantha Hance, the only species in the genus Eomecon, is an angiosperm species endemic to China. Here we investigated the pollination syndrome, pollinator generalization of E. chionantha. Our results showed that the individual flower longevity of E. chionantha was 3–5 days. The flowering phenology of E. chionantha can be divided into five phases. We found significant differences in the pollination efficiency of the different insects visiting E. chionantha with bees and flies being the most efficient pollinators. This, in addition to floral morphology and phenology, suggests that E. chionantha is generalized on bees and flies and possesses an outcrossing, partially self-compatible and pollinator-dependent breeding system.  相似文献   

18.
The Central Indian Highland landscape (CIHL) represents a complex, diverse, and highly human-modified system. Nearly half the landscape is cropland, yet it hosts 21 protected areas surrounded and connected by forests. Changing farming practices with increasing access to irrigation might alter this intensifying landscape in the near future particularly in light of weather variability. We analyzed a decade of remote sensing data for cropping patterns and climatic factors combined with census data for irrigation and demographic factors to understand winter cropping trajectories in the CIHL. We quantified ‘productive cropped area’ (PCA), defined as the area with planted crop that is green at the peak of the winter growing season. We find three primary trajectories in PCA—increasing, fluctuating, and decreasing. The most dominant trend is fluctuating PCA in two-thirds of the districts, ranging from ~2.11 million to ~3.73 million ha between 2001 and 2013, which is associated with village-level access to irrigation and local labor dynamics. In 58 % of all districts, clay soils were associated with winter cropping (p < 0.05). Increasing irrigation is associated with increased winter PCA in most (94 %) districts (p < 0.00001). We find strong negative association between PCA and land surface temperature (LST) in most (66 %) districts (p < 0.01). LST closely corresponds to daytime mean air temperature (p < 0.001) for available meteorological stations. Fine-scale meteorological and socioeconomic data, however, are needed to further disentangle impacts of these factors on PCA in this landscape.  相似文献   

19.
Increasing rates of deforestation in tropical forests have been linked to agriculturalists. A critical concern generating debate is how well communities of trees recover into a more species rich ecosystem after restoration planting. The aim of the study was to evaluate the pattern of recovery of communities of tree, assess the influence of Acanthus pubescens, Lantana camara and Pennisetum purpureum, on the recovery as well as how restoration planting facilitates recruitment of other native tree seedlings along a gradient of forest restoration in Kibale National Park, Uganda after evictions of illegal settlers. We studied six restoration forests ranging in age from 3 to 16 years, naturally regenerating and three primary forests. Our results showed that recovery with natural regeneration was more effective than restoration planting although the latter enhanced recruitment of other native tree seedling. Tree recovery was generally correlated with age so that species density and diversity increased although at different rates. A reverse pattern was found for dominance but no clear pattern was found for tree density (individual/ha). Communities of tree showed directional patterns of change however community composition were still distinct among the different forests. A. pubescens, L. camara and P. purpureum negatively correlated with species density, tree density and diversity but a positive correlation was found for dominance. Restoration planting can reestablish forests with high species density, tree density and diversity, but this is dependent on age and the extent of the herbs, grasses and shrubs cover in tropical forests.  相似文献   

20.
The formation of the spatial structure of the willow warbler (Phylloscopus trochilus) and little bunting (Emberiza pusilla) populations differing in the degree of site fidelity was studied. The area populated by each species was subdivided according to how regularly its parts had been populated over a 16-year period and how synchronous the population dynamics were. The validity of some hypotheses detailing the population formation was tested by comparing simulated population dynamic curves in segments differing in quality with actual curves.  相似文献   

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