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1.
Ecol Evol ; 9(14): 8238-8252, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31380086

RESUMO

Global warming is expected to result in earlier emergence of tree seedlings that may experience higher damages and mortality due to late frost in spring. We monitored emergence, characteristics, and survival of seedlings across ten tree species in temperate mixed deciduous forests of Central Europe over one and a half year. We tested whether the timing of emergence represents a trade-off for seedling survival between minimizing frost risk and maximizing the length of the growing period. Almost two-thirds of the seedlings died during the first growing period. The timing of emergence was decisive for seedling survival. Although seedlings that emerged early faced a severe late frost event, they benefited from a longer growing period resulting in increased overall survival. Larger seedling height and higher number of leaves positively influenced survival. Seedlings growing on moss had higher survival compared to mineral soil, litter, or herbaceous vegetation. Synthesis. Our findings demonstrate the importance of emergence time for survival of tree seedlings, with early-emerging seedlings more likely surviving the first growing period.

2.
Sci Rep ; 8(1): 10894, 2018 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-30022032

RESUMO

Treeline responses to climate change ultimately depend on successful seedling recruitment, which requires dispersal of viable seeds and establishment of individual propagules in novel environments. In this study, we evaluated the effects of several abiotic and biotic drivers of early tree seedling recruitment across an alpine treeline ecotone. In two consecutive years, we sowed seeds of low- and high-elevation provenances of Larix decidua (European larch) and Picea abies (Norway spruce) below, at, and above the current treeline into intact vegetation and into open microsites with artificially removed surface vegetation, as well as into plots protected from seed predators and herbivores. Seedling emergence and early establishment in treatment and in control plots were monitored over two years. Tree seedling emergence occurred at and several hundred metres above the current treeline when viable seeds and suitable microsites for germination were available. However, dense vegetation cover at lower elevations and winter mortality at higher elevations particularly limited early recruitment. Post-dispersal predation, species, and provenance also affected emergence and early establishment. This study demonstrates the importance of understanding multiple abiotic and biotic drivers of early seedling recruitment that should be incorporated into predictions of treeline dynamics under climate change.


Assuntos
Biota , Mudança Climática , Picea/fisiologia , Pinus/fisiologia , Plântula/fisiologia , Estresse Fisiológico , Árvores/fisiologia , Ecossistema , Germinação , Noruega , Estações do Ano
3.
Lima; OPS; 1998. 24 p. ilus.
Monografia em Espanhol | LILACS | ID: lil-209491

RESUMO

Forma parte de un estudio multicéntrico en siete países centroamericanos y tres andinos. Presenta datos descriptivos basados en las palabras en primera voz de los informantes en Lima, Cusco y Piura. Las protagonistas son mujeres mayores de 15 años que se atrevieron a hablar en un lapso de 24 meses, de su situación de violencia fuera del ámbito familiar. La colección cuenta con el informe completo más los anexos de esta investigación, con el mismo código


Assuntos
Humanos , Feminino , Adolescente , Adulto , Pessoa de Meia-Idade , Mulheres Maltratadas , Violência Doméstica , Peru
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