Andrés P., Salgado C., Espelta J.M. (2011) Optimizing nursery and plantation methods to grow Cedrela odorata seedlings in tropical dry agroecosystems. Agroforestry Systems. 83: 225-234.EnllaçDoi: 10.1007/s10457-011-9404-5
Cedrela odorata (Spanish cedar) is a valuable multi-purpose tree which Central American rural communities and farmers give priority to introducing in pastures and home gardens. In order to propose realistic methods for C. odorata production in local nurseries in the dry tropical region of Nicaragua, we studied: (a) the ability of locally collected C. odorata seeds to germinate, (b) seed response to storage under ambient conditions or under cold storage, (c) the effects of irradiance and watering during cultivation on seedling morphology and post-transplantation survival, and (d) the effects of competition from grasses on C. odorata seedlings transplanted to pastures. Seed germination ranged from 55 to 66% and remained constant after 6 months of storage under ambient conditions or cold storage. C. odorata seedling morphology was sensitive to irradiation and watering in the nursery growing period. Deep shade reduced seedling biomass and leafiness and increased specific leaf area and root-to-shoot ratio. Water shortage increased root mass ratio and root-to-shoot ratio and decreased leaf mass ratio. Post-transplantation success was favored by weeding, and was the highest for seedlings grown under deep shade and water restrictions. © 2011 Springer Science+Business Media B.V.
Domene X., Chelinho S., Campana P., Natal-da-Luz T., Alcañiz J.M., Andrés P., Römbke J., Sousa P. (2011) Influence of soil properties on the performance of Folsomia candida: Implications for its use in soil ecotoxicology testing. Environmental Toxicology and Chemistry. 30: 1497-1505.EnllaçDoi: 10.1002/etc.533
Nineteen Mediterranean natural soils with a wide range of properties and the Organisation for Economic Co-operation and Development (OECD) artificial soil were used to assess the influence of soil properties on the results of avoidance and reproduction tests carried out with the soil collembolan species Folsomia candida. Compared to natural soils, the OECD soil was mostly rejected by individuals when a natural soil was offered in avoidance tests, and the number of offspring produced was generally lower than the one obtained in natural soils. None of the soil properties assessed showed a significant influence on the avoidance behavior. More precisely, only soil moisture was included in the model explaining the avoidance response (avoidance increased with increasing differences in moisture), but its contribution was marginally not significant. The model derived explained only 16% of the variance in avoidance response. On the contrary, several soil properties significantly influenced reproduction (number of offspring increased with increasing moisture content, increasing coarse texture, and decreasing nitrogen content). In this case, the model explained 45% of the variance in reproduction. These results, together with the fact that most of the selected soils fulfilled the validity criteria in both avoidance and reproduction tests, confirm the literature experience showing that this species is relatively insensitive to soil properties and hence highly suitable to be used in ecotoxicological tests with natural soils. In addition, our study highlights the need for accuracy in soil moisture adjustment in soil ecotoxicological tests with this species. Otherwise, results of both avoidance and reproduction tests might be biased. © 2011 SETAC.
Domene X., Solà L., Ramírez W., Alcañiz J.M., Andrés P. (2011) Soil bioassays as tools for sludge compost quality assessment. Waste Management. 31: 512-522.EnllaçDoi: 10.1016/j.wasman.2010.10.013
Composting is a waste management technology that is becoming more widespread as a response to the increasing production of sewage sludge and the pressure for its reuse in soil. In this study, different bioassays (plant germination, earthworm survival, biomass and reproduction, and collembolan survival and reproduction) were assessed for their usefulness in the compost quality assessment. Compost samples, from two different composting plants, were taken along the composting process, which were characterized and submitted to bioassays (plant germination and collembolan and earthworm performance). Results from our study indicate that the noxious effects of some of the compost samples observed in bioassays are related to the low organic matter stability of composts and the enhanced release of decomposition endproducts, with the exception of earthworms, which are favored. Plant germination and collembolan reproduction inhibition was generally associated with uncomposted sludge, while earthworm total biomass and reproduction were enhanced by these materials. On the other hand, earthworm and collembolan survival were unaffected by the degree of composting of the wastes. However, this pattern was clear in one of the composting procedures assessed, but less in the other, where the release of decomposition endproducts was lower due to its higher stability, indicating the sensitivity and usefulness of bioassays for the quality assessment of composts. © 2010 Elsevier Ltd.
Alcañiz JM, Ortiz O, Carabassa V, Andrés P (2011) Enmiendas orgánicas y biosólidos para la rehabilitación de terrenos denudados, p: 267- 276. En: Ortiz Silla y Sanchez Navarro (editores), Control de la Degradación del Suelo. Libro de Actas del V Simposio Nacional sobre Control de la Degradación y Uso Sostenible del Suelo (CDUSS), Murcia, 27-30 de junio de 2011, 594 pp. ISBN 978-84-615-1679-7.
Andrés P, Mateos E, Tarrasón D, Cabrera C, Figuerola B (2011) Effects of fresh, composted, and thermally dried sewage sludge on soil microbiota and mesofauna. Applied Soil Ecology 48: 236-242.
Chelinho S, Domene X, Campana P, Natal-da-Luz T, Scheffczyk A, Rombke J, Andrés P, Sousa JP (2011) Improving ecological risk assessment in the Mediterranean area: selection of reference soils and evaluating the influence of soil properties on avoidance and reproduction of the oligochaetes Eisenia andrei and Enchytraeus crypticus. Environmental Toxicology and Chemistry 30: 1050–1058.
Andrés P (2010) Degradación y restauración de los ecosistemas terrestres latinoamericanos. Revista Ambienta 92: 58-70.
Tarrasón D., Urrutia J.T., Ravera F., Herrera E., Andrés P., Espelta J.M. (2010) Conservation status of tropical dry forest remnants in Nicaragua: Do ecological indicators and social perception tally?. Biodiversity and Conservation. 19: 813-827.EnllaçDoi: 10.1007/s10531-009-9736-x
Intensive deforestation is reducing dry tropical forest areas worldwide and increasing its fragmentation. Forest remnants can be the basis for the future recovery of this forest type if appropriate management practices are applied. This requires a better knowledge of their conservation status and the assessment of their perceived value by land users. In this study we compare the structure, species richness and diversity of different types of tropical dry forest remnants in Nicaragua and we assess their conservation status based on a new index: Social simplified Importance Value Index (SsIVI). This index summarizes both ecological indicators and the perception by local stakeholders of the conservation status of the tree species present. Results show that gallery and hillslope forest remnants have higher species richness and diversity than isolated vestigial patches. In all remnants, species richness and diversity is higher in the tree layer than in the regeneration layer. No differences are observed in valorisation among different types of remnants either for the tree layer or for the regeneration layer. In the hillslope forests, where several degrees of disturbance are present, the valorisation decreases with increasing degradation. Results of species composition and forest structure indicate a strong degradation of dry tropical forest remnants in Nicaragua. However, the similar social valorisation of the three types of remnants suggests that they face similar threats but also similar opportunities to be preserved. A decrease in valorisation with increasing degradation warns about the potential loss of the most degraded areas, unless forest restoration is applied. © Springer Science+Business Media B.V. 2009.
Ravera F, Tarrasón D, Andrés P, Grasa R (2009) Proceso y métodos de evaluación integrada participativa de degradación en agroecosistemas semiáridos. Un caso de estudio en un área protegida en el trópico seco nicaragüense. Revista Iberoamericana de Economía Ecológica 13: 79-99.
Domene X., Ramírez W., Solà L., Alcañiz J.M., Andrés P. (2009) Soil pollution by nonylphenol and nonylphenol ethoxylates and their effects to plants and invertebrates. Journal of Soils and Sediments. 9: 555-567.EnllaçDoi: 10.1007/s11368-009-0117-6
Background, aim, and scope Nonylphenol polyethoxylates (NPEOs) are a widely used class of nonionic surfactants known to be toxic and endocrine-disrupting contaminants. Their use and production have been banned in the European Union and substituted by other surfactants considered as environmentally safer. However, their use continues in many countries without any legal control. Discharges of effluents from wastewater treatment plants and the application of sewage sludge application, land-filling, and accidental spillage to soils are the major sources of NPEOs in the environment. The biodegrada-tion of these surfactants is relatively easy, leading to the accumulation of the simplest chemical forms of non-ylphenol ethoxylates (NP, NP1EO, and NP2EO) and nonylphenol carboxy acids (NP2EC or NP1EC). However, these are also the most toxic end-products and have a higher environmental persistence. Compared to aquatic ecosystems, not much is known about the effects of NPEOs in terrestrial organisms, with few studies mainly centered on the effects on plants and soil microorganisms. The main aim of this study is to provide the range of concentrations of NPEOs with ecotoxicological effects on different plants and soil invertebrate species. In addition, we aim to identify the main soil properties influencing their toxicity. Materials and methods Two natural soils collected and OECD artificial soil were used in toxicity bioassays. Two different NPEO formulations were tested. On the one hand, a technical mixture of NPEOs containing chain isomers and oligomers with an average of eight ethoxy units was used for the experiments and is referred to herein as NP8EO. On the other hand, technical-grade 4-nonylphenol 95% purity was also used and called NP in this study. The chemicals were applied and mixed with soil as an acetone solution. The toxicity of NP8EO and NP was assessed in different taxonomical groups (plants, earthworms, enchytraeids, and collembolans) according to their respective standardized methods. The effect on lethal and sublethal endpoints was assessed and, by means of linear and non-linear regression models, the NPEO concentration causing 10% and 50% inhibition was estimated. The influence of soil properties on the toxicity was assessed using generalized linear models (GLM). Results The chemicals tested showed contrasting toxicities, NP being clearly more toxic than NP8EO. There were also substantial differences in the sensitivity of the species and endpoints, together with clearly different toxicities in different soils. Plants were the least affected group compared to soil invertebrates, since plant endpoints were unaffected or only slightly inhibited. In soil invertebrates, reproduction was the most affected endpoint compared to growth or survival. Toxicity was the lowest in OECD artificial soil in comparison to natural soils, with a lower organic matter content. Discussion The higher toxicity of NP, both in plant and soil invertebrate bioassays, is consistent with previously published studies and its relatively high persistence in soil. The low phytotoxicity of NP8EO and NP, unaffected at concentrations over 1 g NP kg-1, also accords with the known low uptake in plants. The effects on soil inverte-brates appeared at lower concentrations than observed in plants, enchytraeids being less affected by NP8EO than earthworms and collembolans. Drastic inhibition in the invertebrate's endpoints generally appeared over 1 g kg-1 for NP8EO and below 1 g kg-1 for NP. The range of concentrations with effects is in agreement with the few similar studies published to date. Generally, the lowest toxicity values were obtained in OECD soil, with the highest organic matter content, while the highest toxicity was found in the PRA soil, with the lowest content. However, few of the models developed by GLM identified organic carbon as a significant factor in decreasing the bioavailability and toxicity of NPEO. The probable explanation for this is the simultaneous contribution of other soil properties and in particular the limited number of soils used in the bioassays. Conclusions A low ecotoxicological risk of NPEOs might be expected for plants and soil invertebrates, since the usual concentrations in soils (below 2.6 mg kg-1) are clearly less than the lowest concentrations reported to be toxic in our study. Recommendations and perspectives Although the apparent risk of NPEOs for soil ecosystems is limited, such risks should not be neglected since significant concentrations in soil could be reached with elevated application rates or when highly polluted sludges are used. More importantly, NPEO concentrations in soils should be maintained low given the extremely high toxicity for aquatic organisms. Despite the reduced leaching of NPEOs, runoff events might transport NP attached to soil particles and affect adjacent aquatic ecosystems. © Springer-Verlag 2009.
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