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11.
Conservation of the Toromiro Tree: Case Study in the Management of a Plant Extinct in the Wild 总被引:1,自引:0,他引:1
Mike Maunder Alastair Culham † Bjorn Alden ‡ Georg Zizka § Cathérine Orliac Wolfram Lobin †† Alberto Bordeu ‡‡ Jose M. Ramirez §§ and Sabine Glissmann-Gough 《Conservation biology》2000,14(5):1341-1350
Abstract: We reviewed the history and conservation of Sophora toromiro , a species that has been extinct in the wild since 1960 but has survived as scattered individuals in botanic gardens and private collections. The short-term conservation of S. toromiro is dependent on the management of surviving ex situ stocks. This is being achieved through international collaboration by a working group established to coordinate the conservation management of the species. Molecular evidence indicates that the species retains greater genetic variability than expected. The greatest amount of genetic variability was located in specimens outside botanic garden collections. No unmodified natural habitat survives on Rapa Nui ( Easter Island); so opportunities to establish a viable wild population are limited. Evidence from past reintroductions indicates that the best short-term opportunity for the species is through conventional horticultural management in botanic gardens and traditional farm plots on Rapa Nui. Some extinct-in-the-wild taxa (sensu World Conservation Union 1994), such as the Toromiro, retain genetic variability, and appropriate reintroduction sites exist. These taxa represent valid priorities for conservation management. 相似文献
12.
de Araújo MC Chaves AP Espinosa DC Tenório JA 《Waste management (New York, N.Y.)》2008,28(11):2177-2182
Every year, the number of discarded electro-electronic products is increasing. For this reason recycling is needed, to avoid wasting non-renewable natural resources. The objective of this work is to study the recycling of materials from parallel wire cable through unit operations of mineral processing. Parallel wire cables are basically composed of polymer and copper. The following unit operations were tested: grinding, size classification, dense medium separation, electrostatic separation, scrubbing, panning, and elutriation. It was observed that the operations used obtained copper and PVC concentrates with a low degree of cross contamination. It was concluded that total liberation of the materials was accomplished after grinding to less than 3 mm, using a cage mill. Separation using panning and elutriation presented the best results in terms of recovery and cross contamination. 相似文献
13.
Hydrogeochemical considerations about the origin of groundwater salinization in some coastal plains of Elba Island (Tuscany,Italy) 总被引:1,自引:0,他引:1
Elena Giménez-Forcada Alberto Bencini Giovanni Pranzini 《Environmental geochemistry and health》2010,32(3):243-257
Several coastal plains of the Elba Island (Marina di Campo, Portoferraio, Schiopparello, Mola, Porto Azzurro and Barbarossa
plains) in Tuscany (Italy) were studied to determine the causes of decline in groundwater quality, using major ion chemistry
to establish the causes of groundwater salinization. The study demonstrates that salinization of coastal plain alluvial aquifers
is not simply linked to seawater intrusion but is also intimately related to inflows from adjacent aquifers. Ionic ratios,
correlation graphs and distribution value maps were employed as the means to understand the hydrochemistry of the study areas.
The Mg/Cl ratio in particular can be considered a good tracer to distinguish the main salinization processes that control
groundwater chemistry. Seawater intrusion only partly determines the chemistry of some groundwaters, which generally belong
to a chloride facies where the salinity is derived principally from freshwater–seawater mixing and the participation of cation
exchange. Proceeding inland groundwater quality seems to be principally determined by the inflow of Mg, Ca-HCO3 or Ca, Na-HCO3 waters formed from the weathering of silicate minerals in adjoining aquifers. Hydrolysis of these minerals is of prime importance
in controlling groundwater chemistry in adjacent alluvial plains. The lateral recharge flows introduce water with a different
chemical composition and this variable of freshwater recharge changes the hydrochemistry as a result of mixing between two
or more waters types. This situation is further complicated when seawater and base exchange reactions participate, due to
seawater intrusion. 相似文献
14.
Humanity's future depends on the preservation of natural ecosystems that supply resources and absorb pollutants. Rural and urban productions are currently based on chemical products made from petroleum, which are responsible for high negative impacts on the Biosphere. In order to prevent those impacts, efficient public policies seeking for sustainable development are necessary. Aiming to assess the load on the environment (considering the gratuitous contributions of natural systems—a donor's perspective) due to human-dominated process, a scientific tool called Emergy Evaluation has been applied in different production systems, including crops and farms. However, there is still a lack of emergy studies in the context of watersheds, probably due to the difficulty of collecting raw data. The present work aims to carry out an assessment of Mogi-Guaçu and Pardo watershed, through the combined use of Emergy Evaluation and Geographical Information System. The agricultural and natural land uses were considered, while urban areas were excluded. Emergy flows (expressed in seJ ha−1 yr−1) obtained for all agricultural and natural land uses were expanded for the whole watershed and the emergy indices were calculated. The results show that the watershed has: low renewability (%R = 32%); low capture of natural resources through high external economic investment (EYR = 1.86); low dependence on natural resources (EIR = 1.16); and moderate load on the environment (ELR = 2.08). Considering a scenario where sugar-cane crops, orchards and pasture areas are converted from conventional to organic management, watershed's emergy performance improved, reaching a new renewability of 38%, but it is still not enough to be considered sustainable. 相似文献
15.
Gloria Massamba-N’Siala Roberto Simonini Piero Cossu Ferruccio Maltagliati Alberto Castelli Daniela Prevedelli 《Marine Biology》2011,158(7):1523-1535
The spatial scale of life-history and demographic variation was investigated in the opportunistic polychaete Ophryotrocha labronica La Greca and Bacci. Individuals were collected along the Italian coasts from three thermally different biogeographical regions
of the Mediterranean Sea. For each region, populations from four harbours were considered, and for each harbour, two sites
were examined. Life-history and demographic traits were investigated after one generation under a common garden experiment,
and their variation at the three spatial scales was assessed. All the traits showed high variability with regard to site.
A number of life-history and all demographic traits also varied according to the biogeographical region. Conversely, no differences
were found between harbours, suggesting that geographical isolation did not contribute to phenotypic variation. Results confirmed
the central role of local conditions for the evolution of life history in species colonizing heterogeneous environments, but
they also pointed to the importance of large-scale factors in shaping the phenotypic responses of O. labronica, demonstrating the need for a multi-scale approach for obtaining a good measure of natural variation in widespread opportunistic
species. 相似文献
16.
Jorge Alberto Achcar Josmar Mazucheli Emílio Augusto Coelho-Barros 《Environmental and Ecological Statistics》2011,18(2):315-329
In this paper we present a hierarchical Bayesian analysis for a predator–prey model applied to ecology considering the use
of Markov Chain Monte Carlo methods. We consider the introduction of a random effect in the model and the presence of a covariate
vector. An application to ecology is considered using a data set related to the plankton dynamics of lake Geneva for the year
1990. We also discuss some aspects of discrimination of the proposed models. 相似文献
17.
Macrophytes release allelochemicals, which affect pelagic cladocerans such as Daphnia. Using population growth experiments, we analysed the effects of allelochemicals from the macrophyte Egeria densa on the interaction between Daphnia mendotae and three littoral cladocerans (Diaphanosoma birgei, Macrothrix triserialis and Simocephalus mixtus). We found that allelochemicals from E. densa increased the abundance of all the tested cladocerans in spite of the presence of a competitor. This effect was stronger (nearly three to four times higher than in controls) for D. birgei and M. triserialis in the absence of D. mendotae. Independent of the presence of allelochemicals, S. mixtus, but not D. birgei and M. triserialis, reduced the abundance of D. mendotae as compared to controls. The rate of population increase (r) per day was significantly elevated due to the presence of Egeria’s allelochemicals (from 0.07–0.16?d?1 without allelochemicals against 0.12–0.24?d?1 with allelochemicals). In our competition experiments, the rates of population increase of the cladocerans were lower than those in single-species cultures when cultured in the absence of allelochemicals. However, in the presence of allelochemicals this trend was not consistent. Thus, the positive effects of Egeria’s allelochemicals over the cladoceran populations may enhance the grazing pressure on phytoplankton. 相似文献
18.
Coastal environments, such as marshes, dunes, or estuaries, are characterized by their high natural values that usually cause them to be subjected to high protection levels, affecting activities taking place within them. This is why the action in these spaces must be based on the use of proper techniques and approaches, which integrate ecology with practical engineering necessities. In this context, the Department of Sciences and Techniques of the Water and Environment of the University of Cantabria, through methods developed in the natural reserve of the Salt Marshes of Santoña and Noja, proposes the use of a working methodology based on the discipline of “ecosystem management” combined with the “adaptive management” methodologies; the application of mathematical, statistical, and specific predictive instruments; and the utilization of an “ecologic niche” as a union between the scientific knowledge of the littoral environments and the true actuation scale of the projects and activities carried out within them. 相似文献
19.
Pau Sunyer Josep Maria Espelta Raúl Bonal Alberto Muñoz 《Behavioral ecology and sociobiology》2014,68(7):1205-1213
Scatter-hoarding rodents influence the population dynamics of plants by acting as seed predators and dispersers. Therefore, rodent foraging preferences for certain seed traits (species, size, condition) have been extensively studied. However, to what extent these preferences are fixed or they track the temporal changes on seed characteristics due to phenological differences has been seldom explored. We studied the temporal variability in seed preferences by wood mouse (Apodemus sylvaticus), according to phenological changes in seed characteristics of two co-occurring oaks (Quercus ilex and Quercus pubescens). The phenology of acorn abundance and the acorn predation/dispersal patterns by rodents were monitored over an entire seeding season. Results revealed temporal changes in rodent preferences for acorns of the two oaks, matching their different seeding phenology (earlier in Q. pubescens and later in Q. ilex). On the other hand, whatever the species considered, rodents preferred larger and sound acorns along the entire season, although the dispersal of infested ones increased slightly during the peaks of acorn drop. The observed influence of seeding phenology on seed choices by rodents warns about inferring definite conclusions regarding their foraging behavior when arising from short-term experiments. Indeed, this study reveals that foraging preferences may be highly dynamic and context-dependent for some seed traits (e.g., species and condition), rather than fixed behavioral patterns. Plasticity in rodent foraging choices may allow them to successfully exploit different oaks with uncoupled seeding phenologies, while potentially favoring their coexistence. 相似文献
20.
R. Wassmann H. U. Neue M. C. R. Alberto R. S. Lantin C. Bueno D. Llenaresas J. R. M. Arah H. Papen W. Seiler H. Rennenberg 《Environmental monitoring and assessment》1996,42(1-2):163-173
Measurements of methane emission rates and concentrations in the soil were made during four growing seasons at the International Rice Research Institute in the Philippines, on plots receiving different levels of organic input. Fluxes were measured using the automated closed chambers system (total emission) and small chambers installed between plants (water surface flux). Concentrations of methane in the soil were measured by collecting soil cores including the gas phase (soil-entrapped methane) and by sampling soil solution in situ (dissolved methane). There was much variability between seasons, but total fluxes from plots receiving high organic inputs (16–24 g CH4 m–2) always exceeded those from the low input plots (3–9 g CH4 m–2). The fraction of the total emission emerging from the surface water (presumably dominated by ebullition) was greater during the first part of the season, and greater from the high organic input plots (35–62%) than from the low input plots (15–23%). Concentrations of dissolved and entrapped methane in the low organic input plots increased gradually throughout the season; in the high input plots there was an early-season peak which was also seen in emissions. On both treatments, periods of high methane concentrations in the soil coincided with high rates of water surface flux whereas low concentrations of methane were generally associated with low flux rates. 相似文献