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1.
The Arabian oryx (Oryx leucoryx) historically ranged across the Arabian Peninsula and neighboring countries until its extirpation in 1972. In 1963–1964 a captive breeding program for this species was started at the Phoenix Zoo (PHX); it ultimately consisted of 11 animals that became known as the ‘World Herd’. In 19781979 a wild population was established at the Shaumari Wildlife Reserve (SWR), Jordan, with eight descendants from the World Herd and three individuals from Qatar. We described the mtDNA and nuclear genetic diversity and structure of PHX and SWR. We also determined the long-term demographic and genetic viability of these populations under different reciprocal translocation scenarios. PHX displayed a greater number of mtDNA haplotypes (n = 4) than SWR (n = 2). Additionally, PHX and SWR presented nuclear genetic diversities of \(\bar{N}_{\text{A}}\) = 2.88 vs. 2.75, \(\bar{H}_{\text{O}}\) = 0.469 vs. 0.387, and \(\bar{H}_{\text{E}}\) = 0.501 vs. 0.421, respectively. Although these populations showed no signs of inbreeding (\(\bar{F}_{\text{IS}}\) ≈ 0), they were highly differentiated (\(G^{\prime\prime}_{\text{ST}}\) = 0.580; P < 0.001). Migration between PHX and SWR (Nm = 1, 4, and 8 individuals/generation) increased their genetic diversity in the short-term and substantially reduced the probability of extinction in PHX during 25 generations. Under such scenarios, maximum genetic diversities were achieved in the first generations before the effects of genetic drift became predominant. Although captive populations can function as sources of genetic variation for reintroduction programs, we recommend promoting mutual and continuous gene flow with wild populations to ensure the long-term survival of this species.  相似文献   

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Trophic state of lakes has been related to catchment land use, but direct links between phytoplankton taxa and land use are limited. Phytoplankton composition, represented by relative cell abundance of phyla, was measured over a period of 4 years in 11 lakes in the Rotorua region, New Zealand. The lakes differed in morphometry, trophic state and land use (as percentage catchment area). We tested whether relative proportion of land uses, indirectly representing relative nutrient loading, was the overarching driver of phytoplankton composition. Trophic state was correlated negatively with native forest and positively with pasture and urban area. Cyanoprokaryota were correlated negatively with native forest and positively with pasture and trophic state, Chlorophyta were correlated positively with native forest and urban land use and negatively with pasture and trophic state, and Bacillariophyta were positively correlated with dissolved reactive silica to dissolved inorganic nitrogen (Si:DIN) and Si to dissolved reactive phosphorus (Si:DRP) ratios. Lakes with higher nutrient loads had higher trophic state and Cyanoprokaryota dominance. Chlorophyta were negatively correlated with Cyanoprokaryota and Bacillariophyta, suggesting competition amongst these groups. Our results apply to lakes potentially subject to changes in catchment land use, which may have implications for trophic state, phytoplankton composition and Cyanoprokaryota blooms.  相似文献   

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Orchid classification has undergone a series of significant changes during the past decade as molecular phylogenetic studies have examined relationships at all taxonomic levels in the family. Today, the 750 genera and 25,000 species of Orchidaceae are organized into five subfamilies, the two largest of which (Epidendroideae and Orchidoideae) are further divided into 19 tribes and 43 subtribes. Whereas some of these groups are relatively small in terms of total species numbers, and may be of little horticultural or medicinal value, they are especially important for understanding orchid evolution and may deserve to be conserved for this reason alone. The question of which orchids to conserve is a complex one, but the science of systematics, including taxonomy and phylogenetics, has an undeniable role to play in answering that question. Among the many ways that phylogenetic trees can assist biologists in setting conservation priorities are by: 1) guiding taxonomists in naming species, which is essential for creating checklists within floras, monographs, and inventories; 2) discovering overlooked, rare or cryptic species that deserve recognition and protection; 3) determining whether or not a taxon is actually a species or simply a variant or hybrid; 4) predicting species that may be of value to humans for economic value; 5) identifying species that may have particularly important scientific value for better understanding the biology of plants. In the same way that we cannot protect all habitats, we may not be able to save every orchid species. Priorities must be established. The Yachang Orchid Reserve has been recognized as important not only because of the number of individual orchid plants that grow there, but also because of its great orchid diversity. Diversity is a product of evolution by natural selection, and the science of phylogenetics has a role to play in better understanding that process.  相似文献   

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The marine life of Canada’s Pacific marine ecosystems, adjacent to the province of British Columbia, may be relatively responsive to rapid oceanographic and environmental change associated with global climate change due to uniquely evolved plasticities and resiliencies as well as particular sensitivities and vulnerabilities, given this dynamic and highly textured natural setting. These marine ecosystems feature complex interfaces of coastal geomorphology, climate, and oceanography, including a dynamic oceanographic and ecological transition zone formed by the divergence of the North Pacific Current into the Alaskan coastal current and the California Current, and by currents transporting warm tropical waters from the south. Despite long-term warming in the region, sea surface temperatures in Canada’s Pacific have been anomalously cool since 2007 with La Niña-type conditions prevailing as we enter a cool phase of the Pacific Decadal Oscillation, possibly masking future warming. When warmer El Niño conditions prevail, many southern species invade, strongly impacting local species and reorganizing biological communities. Acidification and deoxygenation are anomalously high in the region due to the weakening ventilation of subsurface waters resulting from increased stratification. A broad spectrum of biological responses to these changes are expected. Non-climate anthropogenic stressors affect the capacity of biota to adapt to climate changes. It will be challenging to forecast the responses of particular species, and to map climate vulnerabilities accurately enough to help prioritize and guide adaptation planning. It will be more challenging to develop forecasts that account for indirect effects within biological communities and the intricate and apparently non-deterministic behaviours of highly complex and variable marine ecosystems, such as those of Canada’s Pacific. We recommend and outline national and regional climate assessments in Canada and adaptation planning and implementation including integrated coastal management and marine spatial planning and management.  相似文献   

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Large terrestrial carnivores especially have experienced substantial declines in range and numbers. Changes in land use are a main driver of such declines, yet various developing countries have accelerated land use change through state-led land reform programmes. One of the most renowned land reform programmes is Zimbabwe’s fast track land reform programme (FTLRP), which resulted in fast and compulsory subdivision of large commercial farms into indigenized small scale commercial and subsistence farms. Several case studies have shown an impact of the FTLRP on wildlife, however, its effect on wildlife populations at a nationwide scale remains largely unknown. Due to its wide-ranging nature, the cheetah (Acinonyx jubatus) is particularly vulnerable to changes in land use. In this study I used questionnaire survey and citizen science data to determine the population status and distribution of the cheetah 15 years after introduction of the FTLRP. I also assessed the level of human-cheetah conflict, and attitudes of commercial and subsistence farmers towards cheetah. I found dramatic range contractions and population declines, particularly in the landscape outside protected areas. Despite minimal conflict, subsistence farmers were less tolerant to cheetah than commercial farmers. Consequently, land reform is likely to have increased the hostility of the cheetah landscape outside protected areas. This study is one of the most comprehensive species assessments to date. It provides valuable empirical data on the implications of land use change and emphasizes how a lack of knowledge impedes our ability to recognize a species vulnerability to (local) extinction risk.  相似文献   

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Purpose

Built in 1941, the Progreso Pier was the first concrete structure in the world built with nickel-containing stainless steel reinforcement. The Pier has been in service for over 70 years without any significant repair or maintenance activities. The aim of this study was to understand the environmental and economic implications of selecting nickel-containing stainless steel reinforcement using the Progreso Pier as the case study.

Methods

A combined environmental life cycle assessment (LCA) and life cycle costing (LCC) study was conducted. The analysis considered the potential environmental impacts and the net present cost of the stainless steel reinforced structure from cradle to grave and compared it to the same structure using conventional carbon steel.

Results and discussion

The results indicated that while using stainless steel reinforcement resulted in a marginally higher environmental impact after initial construction, this is offset by the increased service life and, hence, less frequent maintenance and reconstruction activities. Relative to the as-built stainless steel reinforcement design, the environmental impacts of the carbon steel reinforced design are between 69 and 79 % higher over the analysis period. Similar observations were made for the other investigated impact categories. The cost implications of using stainless steel reinforcement show economic benefits that are complementary to the environmental benefits. Similar to the LCA, the service life benefits outweigh the higher unit costs for stainless steel, assuming a discount rate of 0.01 % as the baseline scenario. The carbon steel reinforced design has a net present cost that is 44 % higher than the as-built stainless steel reinforcement design. The crossover point for the two designs occurs at year 50, which corresponds to the reconstruction activity. A sensitivity analysis shows that the results and conclusions are sensitive to the choice in discount rate: Rates 3 % and lower produce net present costs that are lower for the as-built design; rates 4 % and higher produce net present costs that are lower for the alternative design.

Conclusions

The study demonstrates how LCA and LCC are complementary tools that can be used in decision-making for sustainable construction. The Progreso Pier exemplifies the importance of considering the entire life cycle with service life and recycling as well as long-term life cycle impacts of infrastructure projects from an environmental and economic perspective.
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The article describes how economic resilience of farming households can be measured using a composite indicator of revealed adaptive actions, and investigates how capabilities of farm households to recombine human, financial, natural and physical capitals are linked to observed economic resilience to land set-aside interventions. The land set-aside intervention known as the Grain for Green Project (GGP), which has been altering livelihoods of farming households in China’s Loess Hills since 1999, is taken as a case study. Household surveys were conducted in three V-shaped valleys and three riparian areas in Yanhe Township in northwestern China in an effort to measure household resilience and explore its’ relationship to forms of capital. A composite index of adaptive strategies that can reorganize livelihood activities under land set-aside intervention into a new economic equilibrium is crafted using an objective weighting scheme based on principal component analysis. Subsequently, a multiple regression model was utilized to examine the relationship between the composite resilience index and various indicators related to human, social, financial, natural and physical capitals. The results reveal the latent structure and internal correlations of adaptive strategies, and present quantitative evidence about the relationship between livelihood capitals and household economic resilience. The analysis shows that household resilience deteriorates when the ratio of GGP land to cultivated farmland goes above a threshold level, and revealed that interventions targeting various forms of capitals can enhance the economic resilience for households to conservation efforts.  相似文献   

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This study quantifies the nationwide land cover and long-term changes in forests and its implications on forest fragmentation in Nepal. The multi-source datasets were used to generate the forest cover information for 1930, 1975, 1985, 1995, 2005 and 2014. This study analyzes distribution of land cover, rate of deforestation, changes across forest types, forest canopy density and pattern of fragmentation. The land cover legend for 2014 is consisting of 21 classes: tropical dry deciduous sal forest, tropical moist deciduous sal forest, subtropical broad-leaved forest, subtropical pine forest, lower temperate broad leaved forest, upper temperate broad leaved forest, lower temperate mixed broad leaved forest, upper temperate mixed broad leaved forest, temperate needle leaved forest, subalpine forest, plantations, tropical scrub, subtropical scrub, temperate scrub, alpine scrub, grassland, agriculture, water bodies, barren land and settlements. The forest cover statistics for Nepal obtained in this study shows an area of 76,710 km2 in 1930 which has decreased to 39,392 km2 in 2014. A net loss of 37,318 km2 (48.6%) was observed in last eight decades. Analysis of annual rate of net deforestation for the recent period indicates 0.01% during 2005–2014. An increase in the number of forest patches from 6925 (in 1930) to 42,961 (in 2014) was noticed. The significant observation is 75.5% of reduction in core 3 forest, whereas, patch, perforated and edge classes show the increase in percentage of fragmentation classes from 1930 to 2014. The results of this work will support the understanding of deforestation and its consequences on fragmentation for maintaining and improving the forest resources of Nepal.  相似文献   

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BackgroundA family history of bladder cancer has been associated with the risk of bladder cancer, but quantification of the excess risk in different populations is still a relevant issue. Further, the role of a family history of other cancers on the risk of bladder cancer remains unclear.MethodsWe analyzed data from an Italian case–control study, including 690 bladder cancer cases and 665 hospital controls. Odds ratios (ORs) were estimated through unconditional logistic regression models, adjusted for sex, age, study center, year of interview and further for education, smoking and sibling’s number.ResultsThe OR for family history of bladder cancer was 2.13 (95% confidence intervals (95%CIs) 1.02–4.49) from the model with partial adjustment, and 1.99 (95%CI 0.91–4.32) after additional adjustment for smoking and siblings’ number, based on 23 cases (3.3%) and 11 controls (1.7%) with a family history of bladder cancer. The fully adjusted OR was 3.77 when the relative was diagnosed at age below 65 years. Smokers with a family history of bladder cancer had a four-fold increased risk compared to non-smokers without a family history. Bladder cancer risk was significantly increased among subjects with a family history of hemolymphopoietic cancers (OR = 2.97, 95%CI 1.35–6.55). Family history of cancer at other sites showed no significant association with bladder cancer risk.ConclusionThis study confirms an approximately two-fold increased risk of bladder cancer for family history of bladder cancer, and indicates a possible familial clustering of bladder cancer with cancers of the hemolymphopoietic system.  相似文献   

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PurposeThis research determines the extent to which farmers benefit from agricultural extension activities and services through realizing higher biological crop yields in the Al-Baha region of the Kingdom of Saudi Arabia. Additionally, the nature of the relationship between the personal, economic and social characteristics of farmers and the degree to which they benefit from agricultural extension activities and services are studied.MethodologyA simple random sample representing the community of 315 farmers was drawn. Data were collected through a personal interview with a pre-tested questionnaire to satisfy the objectives of the study. Data are subjected to analyses and are interpreted in terms of percentages, arithmetic averages, and standard deviations in addition to the simple Pearson correlation coefficients.ResultsThe results show that most of the respondents depend on personal experience, friends, family and neighbors, merchants and sellers of agricultural production supplies as sources of agricultural information for enhanced crop yields. Multiple regression analysis reveals that both the educational status and the agricultural information sources are important factors that increase farmers benefit from extension activities. Farmers receive most benefits from the extension activities and services from bringing in foreign workers, conducting field trips to farms, and identifying problems faced by farmers.Research limitations/implicationsThe outcome of this questionnaire limits generalization of the findings for other parts of the Kingdom due to geographical and natural resources variations.Practical implicationsThe personal and socio-economic characteristics of the surveyed population provide the extension service with insight into their composition – a basis to formulate workable extension programs. For the extension planners of the area, this effort provides a baseline study and may assist with targeting the appropriate farmers and catering the right solutions to the problems. Such a study will help devise meaningful extension programs and save time and resources.Originality/valueLittle previous research on the usefulness of the Extension Service has been conducted in the region.ConclusionsEffective, well-planned extension programs targeting the educated and mature farmers provided more benefits and helped them obtain higher crop yields.  相似文献   

14.
The effects of armed conflict on biodiversity are an emerging concern in conservation due in part to the occurrence of war in biodiversity hotspots, though few studies have addressed it. We investigate this topic by examining changes in forest cover on the Atlantic Coast of Nicaragua from 1978 to 1993, a period covering their civil war. We predict an increase in forest cover between pre- and post-conflict periods as residents abandoned agriculture plots and migrated from conflict areas. We used a remote sensing approach to detect changes in forest cover area and fragmentation at two study sites. Results confirmed that in the first 5–7 years of the conflict, reforestation was greater than deforestation, but in the latter years of the conflict deforested land almost doubled that which was reforested. Although some forest loss was due to Category 4 Hurricane Joan, several conflict-related factors were partially responsible for these results, such as mass human migration and land reform. Understanding how and why forest cover changes during periods of conflict can help conservationists protect resources both during war and in the tumultuous period following the cessation of violence when nascent governments lack the power to effectively govern and community institutions are fractured by war. In areas where the livelihoods of people are directly dependent on local resources, anticipating ecological and social impacts can help improve future conservation efforts.  相似文献   

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Kartagener’s syndrome is a very rare congenital malformation comprising of a classic triad of sinusitis, situs inversus and bronchiectasis. Primary ciliary dyskinesia is a genetic disorder with manifestations present from early life and this distinguishes it from acquired mucociliary disorders. Approximately one half of patients with primary ciliary dyskinesia have situs inversus and, thus are having Kartagener syndrome. We present a case of 12 year old boy with sinusitis, situs inversus and bronchiectasis. The correct diagnosis of this rare congenital autosomal recessive disorder in early life is important in the overall prognosis of the syndrome, as many of the complications can be prevented if timely management is instituted, as was done in this in this case.  相似文献   

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《植物生态学报》2014,38(6):576
Aims An understanding on the living communities of the state’s key protected wild plants and the ability in utilizing resources and occupying ecological spaces by different populations is essential to the protection and propagation of rare and endangered plant species. We use our findings to highlight the knowledge gaps in the conservation strategies for the endangered species.
Methods Field investigations were conducted during 2009-2011. Based on the survey data on 70 forest plots in the Bawangling protected area, the niche breadths and overlaps of 12 species listed as the state’s key protected plants were calculated and analyzed.
Important findings The 12 species, by their niche breadth values in descending order, include Aquilaria sinensis, Nephelium topengii, Camellia sinensis var. assamica, Alseodaphne hainanensis, Keteleeria hainanensis, Podocarpus imbricatus, Firmiana hainanensis, Parakmeria lotungensis, Cephalotaxus mannii, Michelia hedyosperma, Ixonanthes reticulata, Dacrydium pierrei. The niche breadth value of a species is closely related to its range of geographical distribution; both Dacrydium pierrei and Parakmeria lotungensis had a narrow niche breadth corresponding to their narrow ranges of altitudinal distribution. In general, the niche overlap value is higher between species with greater niche breadth; the highest niche overlap value of 0.872 was found between Camellia sinensis var. assamica and Keteleeria hainanensis. However, the niche overlap value between species with smaller niche breadth could also be high; e.g. the niche overlap value was relatively high (0.693) between two species with smaller niche breadth, Michelia hedyosperma and Firmiana hainanensis, indicating that niche overlap value is dependent upon the biological characteristics and requirements for environmental resources of the species of comparison. Some species with low niche breadth values (e.g. Michelia hedyosperma and Ixonanthes reticulata) were found to have smaller populations. Due to lack of suitable community and habitats, these plant species are in dire need of more attention and prioritization for conservation. In conclusion, for the better protection and propagation of these endangered plants in the future, we should combine knowledge of their biological characteristics with that of their living communities such as the montane rainforests, etc.  相似文献   

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Yeast is frequently used as a probiotic in aquaculture with the potential to substitute for antibiotics. In this study, the involvement and extent to which the viability of yeast cells and thus the secretory metabolites released from the yeast contribute to effects of baker’s yeast was investigated in Nile tilapia. No yeast, live yeast or heat-inactivated baker’s yeast were added to basal diets high in fishmeal and low in soybean (diet A) or low in fishmeal and high in soybean (diet B), which were fed to fish for 8 weeks. Growth, feed utilization, gut microvilli morphology, and expressions of hsp70 and inflammation-related cytokines in the intestine and head kidney were assessed. Intestinal microbiota was investigated using 16S rRNA gene pyrosequencing. Gut alkaline phosphatase (AKP) activity was measured after challenging the fish with Aeromonas hydrophila. Results showed that live yeast significantly improved FBW and WG (P < 0.05), and tended to improve FCR (P = 0.06) of fish compared to the control (no yeast). No significant differences were observed between inactivated yeast and control. Live yeast improved gut microvilli length (P < 0.001) and density (P < 0.05) while inactivated yeast did not. The hsp70 expression level in both the intestine and head kidney of fish was significantly reduced by live yeast (P < 0.05) but not inactivated yeast. Live yeast but not inactivated yeast reduced intestinal expression of tnfα (P < 0.05), tgfβ (P < 0.05 under diet A) and il1β (P = 0.08). Intestinal Lactococcus spp. numbers were enriched by both live and inactivated yeast. Lastly, both live and inactivated yeast reduced the gut AKP activity compared to the control (P < 0.001), indicating protection of the host against infection by A. hydrophila. In conclusion, secretory metabolites did not play major roles in the growth promotion and disease protection effects of yeast. Nevertheless, secretory metabolites were the major contributing factor towards improved gut microvilli morphology, relieved stress status, and reduced intestinal inflammation of Nile tilapia fed diets supplemented with baker’s yeast.  相似文献   

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Molecular Biology Reports - Alzheimer’s disease (AD) is the most common neurodegenerative disorder in humans and presents a major health problem throughout the world. The etiology of AD is...  相似文献   

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