The abiotic environment of Heliamphora nutans (Sarraceniaceae): pedological and microclimatic observations on Roraima Tepui (original) (raw)
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The effect of soil nutrient status on prey utilization in four carnivorous plants
Oecologia, 1991
The hypothesis that carnivorous plants are less responsive to prey at high soil nutrient levels than at lower levels (Givnish et al. 1984) is tested on four plant species (Drosera rotundifolia, Pinguicula alpina, P. villosa and P. vulgaris) from a subarctic environment. The response, measured in terms of seven characteristics (winter bud weight, winter bud nitrogen and phosphorus content, flowering frequency, total seed weight, seed number and weight per seed), was analysed. Although all species responded to prey supply the response varied depending on the characteristic and species concerned. In 5 cases (out of 28 tests) the hypothesis was supported, whereas in 1 case it was refuted, i.e. the response to prey was higher for plants supplied with soil nutrients. In the remaining three-quarters of the tests, responses to prey were not significantly different between the two nutrient levels. Thus, the hypothesis that the response to prey diminishes as soil nutrient availability increases was not supported by our findings. A modification of the model presented by Givnish et al. (1984) is therefore suggested. This modified model measures the cost of carnivory as loss in growth rate and assumes that responses to prey remain unchanged as the soil nutrient content increases. Although the distribution of carnivorous plants is still predicted to be limited mainly to wet and sunny but nutrient-poor sites, the modified model also allows for their occurrence in richer habitats, provided competition is low.
2015
La résorption est l’une des plus importantes stratégies d’utilisation des nutriments développées par les plantes. Le ratio de la surface foliaire à la masse sèche (SLA) est lié aux nutriments foliaires. Dans la présente étude, les changements de concentration en SLA, N et P, le rapport N/P et la teneur en C des feuilles de lumière et d’ombre de la liane sempervirente Hedera helix L. ont été étudiés au long de l’année sur un gradient altitudinal. L’efficience (RE) et l’efficacité (RP) de la résorption foliaire ont également été calculées dans les feuilles de lumière et celles d’ombre. Les traits foliaires ont montré des changements significatifs entre les localités et au cours de l’année. Des différences significatives sont apparues entre les feuilles de lumière et celles d’ombre pour ce qui concerne le SLA, la concentration en N et la teneur en C, mais se sont avérées dépendantes des différences d’altitude. Toutefois, aucune différence significative de concentration en P n’a été tro...
New Phytologist, 2008
Plasticity of leaf nutrient content and morphology, and macronutrient limitation were examined in the northern pitcher plant, Sarracenia purpurea subsp. purpurea, in relation to soil nutrient availability in an open, neutral pH fen and a shady, acidic ombrotrophic bog, over 2 yr following reciprocal transplantation of S. purpurea between the wetlands. • In both wetlands, plants were limited by nitrogen (N) but not phosphorus (P) (N content < 2% DW −1 , N : P < 14) but photosynthetic quantum yields were high (F V / F M > 0.79). Despite carnivory, leaf N content correlated with dissolved N availability to plant roots (leaf N vs , r 2 = 0.344, P < 0.0001); carnivorous N acquisition did not apparently overcome N limitation. • Following transplantation, N content and leaf morphological traits changed in new leaves to become more similar to plants in the new environment, reflecting wetland nutrient availability. Changes in leaf morphology were faster when plants were transplanted from fen to bog than from bog to fen, possibly reflecting a more stressful environment in the bog. • Morphological plasticity observed in response to changes in nutrient supply to the roots in natural habitats complements previous observations of morphological changes with experimental nutrient addition to pitchers.
Seasonal and altitudinal changes in leaf nutrient concentrations of Hedera helix L. (Araliaceae)
2015
La resorption est l’une des plus importantes strategies d’utilisation des nutriments developpees par les plantes. Le ratio de la surface foliaire a la masse seche (SLA) est lie aux nutriments foliaires. Dans la presente etude, les changements de concentration en SLA, N et P, le rapport N/P et la teneur en C des feuilles de lumiere et d’ombre de la liane sempervirente Hedera helix L. ont ete etudies au long de l’annee sur un gradient altitudinal. L’efficience (RE) et l’efficacite (RP) de la resorption foliaire ont egalement ete calculees dans les feuilles de lumiere et celles d’ombre. Les traits foliaires ont montre des changements significatifs entre les localites et au cours de l’annee. Des differences significatives sont apparues entre les feuilles de lumiere et celles d’ombre pour ce qui concerne le SLA, la concentration en N et la teneur en C, mais se sont averees dependantes des differences d’altitude. Toutefois, aucune difference significative de concentration en P n’a ete tro...
Resource and top-predator regulation in the pitcher plant (Sarracenia purpurea) inquiline community
2002
Abstract. The effects of top-down and bottom-up forces on species abundance and diversity were quantified in the inquiline communities found in the water-filled leaves of the pitcher plant, Sarracenia purpurea. A press field experiment was conducted in which the abundances of resources (dead ants) and the top predators (larva of the mosquito Wyeomiia smithii) were each maintained at three levels in a factorial design for 23 d. Abundances of mites, rotifers, protozoans, and bacteria increased significantly with prey addition. Protozoan species richness also increased with increasing resource levels, whereas additional resources did not affect bacterial species richness. Increases in top-predator density decreased rotifer abundance but increased bacterial abundance and species richness. Increases in bacterial abundance and richness indicate that a trophic cascade occurs via the larvae, rotifer, and bacteria pathway; omnivory appears to be not strong enough to affect the trophic cascad...
Se evalúo el efecto de tres parches de vegetación de herbáceas: cojines de Geranium sibbaldioides, tapetes de Lachemilla orbiculata y pastizal de Holcus lanatus-Rumex acetosella, sobre el crecimiento y la supervivencia de cinco especies leñosas heliófilas: Hesperomeles goudotiana, Cestrum buxifolium, Pentacalia pulchella, Pentacalia ledifolia y Bucquetia glutinosa. En cada uno de los ambientes se delimitaron parcelas con y sin malla para evitar la depredación por Cavia porcellus. Unicamente en las parcelas sin malla de pastizal de H. lanatus- R. acetosella se presentó depredación de los individuos sembrados. Los individuos de P. ledifolia y P. pulchella fueron las especies mas palatables y tambien con las mayores tasas de crecimiento en todos los ambientes. Los resultados obtenidos indican que los efectos positivos de los parches de herbáceas sobre la supervivencia y el crecimiento de las plantas pioneras varían de acuerdo con las plantas que estan involucradas en dicha interacción....
Mudanças climáticas e a floração de espécies selecionadas de plantas
2014
Mestrado em Biologia AplicadaAs temperaturas globais estão a aumentar rapidamente, promovendo mudanças importantes em comunidades de plantas e contribuindo para a perda global de biodiversidade. Das respostas biológicas para o aquecimento global, as mudanças no tempo dos eventos fenológicos como floração estão entre as mais sensíveis e importantes, tanto do ponto de vista biológico como económico. As fontes mais confiáveis de dados para monitorizar os eventos de ciclo de vida são os conjuntos de dados compilados sistematicamente por estações fenológicas. Embora estes sejam relativamente abundantes na Europa Central e do Norte, são escassos em Portugal. A falta de observações fenológicas pode, contudo, ser preenchida por coleções biológicas em herbários e museus, contanto que algum método de correção seja aplicado para superar as diferenças em pontos de amostragem. O objetivo principal deste trabalho foi encontrar um modelo que possa ser utilizado para corrigir as diferenças geográfi...
Journal of Ecology, 1998
The e}ect of supplementary feeding on growth and reproduction of three car! nivorous plants species was investigated over a 5!year period[ Pinguicula alpina\ P[ villosa and P[ vulgaris populations growing at two altitudes in a subarctic environment were fed with fruit~ies "Drosophila melanogaster#[ 1 Fed plants increased in size relative to control plants during the _rst years[ Sub! sequently a stable size di}erence between feeding levels was established[ The weight of the over!wintering part was higher in fed plants than in control plants[ 2 The~owering frequency "i[e[ proportion of plants in a population carrying~owers# was also higher in the fed plants[ The proportion of~owering plants increased in the feeding treatment compared to control plants during more!or!less the whole experimental feeding period "4Ð5 years#[ Seed production also increased slowly in response to feeding[ 3 No feeding e}ect on nitrogen and phosphorus concentrations in seeds and over! wintering parts was found[ 4 In most characteristics the high!altitude populations were less responsive than populations growing at low altitude[ In the high!altitude population reproduction failed repeatedly\ suggesting that seed output may be more dependent on abiotic factors than on resource availability in cold environments[ 5 Pinguicula villosa and P[ vulgaris used the new resources the same summer for increased leaf rosette growth and current reproduction\ showing these species to be income breeders\ while the third species "P[ alpina# allocated a larger proportion to storage and future reproduction\ characteristic of a capital breeder[ Keywords] capital breeder\ carnivorous plant\ income breeder\ nutrients\ Pinguicula\ resource allocation