Effects of climate on pollination networks in the West Indies

González A.M.M., Dalsgaard B., Ollerton J., Timmermann A., Olesen J.M., Andersen L., Tossas A.G. (2009) Effects of climate on pollination networks in the West Indies. Journal of Tropical Ecology. 25: 493-506.
Enllaç
Doi: 10.1017/S0266467409990034

Resum:

We studied the effect of climate on the plant-pollinator communities in the West Indies. We constructed plots of 200 m 5 m in two distinct habitats on the islands of Dominica, Grenada and Puerto Rico (total of six plots) and recorded visitors to all plant species in flower. In total we recorded 447 interactions among 144 plants and 226 pollinator species. Specifically we describe how rainfall and temperature affect proportional richness and importance of the different pollinator functional groups. We used three measures of pollinator importance: number of interactions, number of plant species visited and betweenness centrality. Overall rainfall explained most of the variation in pollinator richness and relative importance. Bird pollination tended to increase with rainfall, although not significantly, whereas insects were significantly negatively affected by rainfall. However, the response among insect groups was more complex; bees were strongly negatively affected by rainfall, whereas dipterans showed similar trends to birds. Bird, bee and dipteran variation along the climate gradient can be largely explained by their physiological capabilities to respond to rainfall and temperature, but the effect of climate on other insect pollinator groups was more obscure. This study contributes to the understanding of how climate may affect neotropical plant-pollinator communities. © Cambridge University Press 2009.

Llegeix més

Relationship between body size and homing ability in the genus Osmia (Hymenoptera; Megachilidae)

Guédot C., Bosch J., Kemp W.P. (2009) Relationship between body size and homing ability in the genus Osmia (Hymenoptera; Megachilidae). Ecological Entomology. 34: 158-161.
Enllaç
Doi: 10.1111/j.1365-2311.2008.01054.x

Resum:

1. The maximum homing ability of female bees, that is, their capacity to return to the nest after being displaced a certain distance, is considered to be an estimate of their maximum foraging distance. 2. The present study provides data on homing ability and body weight for Osmia lignaria and combines them with data for five other congenerics, O. rufa, O. cornuta, O. pedicornis, O. cornifrons, and O. emarginata for analysis. These species are important pollinators of spring-flowering plants, and some have been developed as commercial crop pollinators. 3. It is shown that homing ability is positively and linearly related to body weight (r2 = 0.81; P = 0.01). 4. These results should be of use in selecting Osmia species as potential crop pollinators and establishing adequate buffer distances around genetically modified crops.

Llegeix més

A geographic selection mosaic in a generalized plant-pollinator-herbivore system

Gómez J.M., Perfectti F., Bosch J., Camacho J.P.M. (2009) A geographic selection mosaic in a generalized plant-pollinator-herbivore system. Ecological Monographs. 79: 245-263.
Enllaç
Doi: 10.1890/08-0511.1

Resum:

The concept of Selection Mosaic is central to the Geographic Mosaic Theory of Coevolution. Most information on coevolving interactions, however, comes from specialized organisms. In contrast, an accurate understanding of the effect of geographically varying evolutionary dynamics on the evolution of generalist organisms is lacking, although these kinds of organisms are the most frequent in nature. In flowering plants, pollinators and herbivores are important selective agents. In this study we investigate whether a geographic selection mosaic for floral traits in a generalist plant, Erysimum mediohispanicum (Brassicaceae), can be mediated by the interplay of mutualistic and antagonistic interacting organisms. In eight populations we quantified the selection exerted by these organisms on several plant traits. We found significant spatial variation in pollinator assemblage. In different populations, the main pollinators belonged to different functional groups (beeflies, large bees, small bees, and beetles). Damage by ungulates also varied among populations. Consequently, we found that different populations were under different selective regimes, and the traits affected by selection depended on the local interaction intensity with pollinators and mammal herbivores. Some traits, such as flower number and stalk height, were selected similarly in most populations. Other traits, such as corolla diameter and tube length, were selected only in some populations. Finally, we found divergent selection for some traits, such as corolla tube width and corolla shape, which were selected in contrasting directions in different localities. This spatial variation in selective scenarios results in populations with strong selective regimes (hot spots) intermingled with populations with weak selective regimes (cold spots). Four important outcomes emerge from the E. mediohispanicum selection mosaic. (1) Interactions with generalist organisms may produce strong selection. (2) Spatial changes in main pollinators result in divergent selection across populations. (3) Geographic mosaics depend on a balance between mutualistic and antagonistic selection. (4) Selection mosaics operate at fairly small spatial scales. These findings will surely contribute to expanding the conceptual framework of the Geographic Mosaic Theory of Coevolution. © 2009 by the Ecological Society of America.

Llegeix més

Evaluating the effect of drier and warmer conditions on water use by Quercus pyrenaica

Hernández-Santana V., Martínez-Vilalta J., Martínez-Fernández J., Williams M. (2009) Evaluating the effect of drier and warmer conditions on water use by Quercus pyrenaica. Forest Ecology and Management. 258: 1719-1730.
Enllaç
Doi: 10.1016/j.foreco.2009.07.038

Resum:

Under climate change, severe and recurrent droughts can reduce forest production and cause widespread tree dieback. The response of different vegetation types to climate change can vary greatly and, therefore, must be individually assessed. This study was carried out in a Mediterranean oak forest (Quercus pyrenaica) subject to seasonal summer drought. To examine the response of the forest to the climate conditions predicted under climate change, a Soil-Vegetation-Atmosphere Transfer model [SPA, Williams, M., Rastetter, E.B., Fernandes, D.N., Goulden, M.L., Wofsy, S.C., Shaver, G.R., Melillo, J.M., Munger, J.W., Fan, S.M., Nadelhoffer, K.J. 1996. Modelling the soil-plant-atmosphere continuum in a Quercus-Acer stand at Harvard Forest: the regulation of stomatal conductance by light, nitrogen and soil/plant hydraulic properties. Plant, Cell, Environment 19, 911-927] was used. The model was parameterized using mostly local measurements (independent of the verification data) and tested against in situ sap flow measurements obtained during year 2007. The predictions of the model were broadly consistent with the observed dynamics of sap flow (the model explained 71% of the variance in daily transpiration and 75% of half-hourly sap flow), leaf water potentials and soil water content. Once the model had been validated, simulations were carried out under warmer and dryer conditions. Predicted warmer conditions (4 °C) caused a moderate increase in total simulated transpiration. Less frequent precipitation (40% longer dry periods between rainfall events) had very little effect on transpiration. In contrast, transpiration was reduced by 17% when the soil water reserves at the beginning of the summer were lower than in 2007, corresponding to those measured in a very dry year (2005). The reduction was exacerbated when changes in temperature and rainfall were also considered (up to 28% decline in transpiration). The higher atmospheric CO2 concentrations (712 ppm) simulated together with climate change, did not prevent the decline in tree water use or soil water storage at the end of the summer. All scenarios caused the soil water storage to reach extremely low values at the end of the dry season (a minimum of 25 mm). It is concluded that climate change is likely to have a negative impact on tree water use and soil water resources in the study area, increasing the water deficit by as much as 30%. © 2009 Elsevier B.V.

Llegeix més

Ecosystem services in dynamic and contested landscapes: The case of UK uplands

Hubacek K., Beharry N., Bonn A., Burt T., Holden J., Ravera F., Reed M., Stringer L., Tarrasón D. (2009) Ecosystem services in dynamic and contested landscapes: The case of UK uplands. What is Land For?: The Food, Fuel and Climate Change Debate. : 167-186.
Enllaç
Doi: 10.4324/9781849774673

Resum:

[No abstract available]

Llegeix més

Invasive plant integration into native plant-pollinator networks across Europe.

Vila M, Bartomeus I, Dietzsch A, Petanidou T, Steffan-Dewenter I, Stout J, Tscheulin T (2009) Invasive plant integration into native plant-pollinator networks across Europe. Proceedings of the Royal Society B 276: 3887-3893.

Breeding system and pollen limitation of two supergeneralist alien plants invading Mediterranean shrublands.

Bartomeus I, Vilà M (2009) Breeding system and pollen limitation of two supergeneralist alien plants invading Mediterranean shrublands. Australian Journal of Botany 57: 109-115.

SIGPesca. An Interoperable GIS Tool for the Coastal Knowledge and Management.

Serral I, Pons X, Jordana R, Allué R (2009) SIGPesca. An Interoperable GIS Tool for the Coastal Knowledge and Management. Journal of Coastal Research 56: 1587-1591.

Recuperación de la vegetación después de la eliminación de Carpobrotus spp. en la costa de Andalucía.

Andreu J, Manzano E, Bartomeus I, Dana ED, Vilà M (2009) Recuperación de la vegetación después de la eliminación de Carpobrotus spp. en la costa de Andalucía. Poster. 3º Congreso Nacional sobre Especies Exóticas Invasoras. Grupo Especialista en Invasiones Biológicas. Zaragoza, 11 novembre (pòster).

An assessment of stakeholder perceptions and management of noxious alien plants in Spain.

Andreu J, Vilà M, Hulme P (2009) An assessment of stakeholder perceptions and management of noxious alien plants in Spain. Environmental Management 43: 1244-1255 doi:10.1007/s00267-009-9280-1.

Pàgines