• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • 1
  • Tagged with
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Phylogenetic composition of native island floras influences naturalized alien species richness

Bach, Wilhelmine, Kreft, Holger, Craven, Dylan, König, Christian, Schrader, Julian, Taylor, Amanda, Dawson, Wayne, Essl, Franz, Lenzner, Bernd, Marx, Hannah E., Meyer, Carsten, Pergl, Jan, Pyšek, Petr, van Kleunen, Mark, Winter, Marten, Weigelt, Patrick 25 November 2024 (has links)
Islands are hotspots of plant endemism and are particularly vulnerable to the establishment (naturalization) of alien plant species. Naturalized species richness on islands depends on several biogeographical and socioeconomic factors, but especially on remoteness. One potential explanation for this is that the phylogenetically imbalanced composition of native floras on remote islands leaves unoccupied niche space for alien species to colonize. Here, we tested whether the species richness of naturalized seed plants on 249 islands worldwide is related to the phylogenetic composition of their native floras. To this end, we calculated standardized effect size (ses) accounting for species richness for three phylogenetic assemblage metrics (Faith’s phylogenetic diversity (PD), PDses; mean pairwise distance (MPD), MPDses; and mean nearest taxon distance (MNTD), MNTDses) based on a phylogeny of 42 135 native island plant species and related them to naturalized species richness. As covariates in generalized linear mixed models, we included native species richness and biogeographical, climatic and socioeconomic island characteristics known to affect naturalized species richness. Our analysis showed an increase in naturalized species richness with increasing phylogenetic clustering of the native assemblages (i.e. native species more closely related than expected by chance), most prominently with MPDses. This effect, however, was smaller than the influence of native species richness and biogeographical factors, e.g. remoteness. Further, the effect of native phylogenetic structure (MPDses) on naturalized species richness was stronger for smaller islands, but this pattern was not consistent across all phylogenetic assemblage metrics. This finding suggests that the phylogenetic composition of native island floras may affect naturalized species richness, particularly on small islands where species are more likely to co-occur locally. Overall, we conclude that the composition of native island assemblages affects their susceptibility to plant naturalizations in addition to other socioeconomic and biogeographical factors, and should be considered when assessing invasion risks on islands.
2

Flora alòctona de les Illes Balears. Ecología de dos especies invasoras: Carpobrotus edules y Carpobrotus aff. acinaciformis

Moragues Botey, Eva 24 March 2006 (has links)
La llegada de plantas exóticas fuera de su rango de distribución original y su posterior asentamiento en ecosistemas naturales no es una excepción en las Islas Baleares. En la actualidad tenemos 308 especies no nativas naturalizadas y subespontáneas que representan el 16% del total de la flora Balear. En esta tesis se ha evaluado el estado de la cuestión a nivel global y local. Se ha confeccionado el primer catálogo de flora introducida y se ha analizado cuales de ellas son más abundantes y peligrosas; así como también qué ecosistemas son más vulnerables a la introducción de éstas. También se ha profundizado en el conocimiento de dos de las especies exóticas más peligrosas en el litoral Balear: Carpobrotus edulis y C. affine acinaciformis. Se ha evaluado su influencia sobre la polinización, su tasa de crecimiento bajo diferentes escenarios ambientales, se ha confeccionado un modelo de crecimiento y se ha evaluado su impacto sobre la composición y estructura de las comunidades nativas. / L'arribada de plantes exòtiques fora del seu rang de distribució original i el seu posterior assentament a ecosistemes naturals no és una excepció a les Illes Balears. A l'actualitat tenim 308 espècies no natives naturalitzades i subespontànies que representen el 16% del total de la flora Balear. En aquesta tesi s'ha avaluat l'estat de la qüestió a nivell global i local. S'ha confeccionat el primer catàleg de flora introduïda i s'han analitzat quines d'elles són més abundants i perilloses; així com també quins ecosistemes són més vulnerables a la introducció d'aquestes. També s'ha profunditzat en el coneixement de dues de les espècies exòtiques més perilloses del litoral Balear: Carpobrotus edulis y C. affine acinaciformis. S'ha avaluat la seva influència damunt els vectors de pol·linització, la taxa de creixement a diferents escenaris ambiental, s'ha confeccionat un model de creixement, i s'ha avaluat el seu impacte damunt la composició i estructura de les comunitats natives. / The constant arrival of exotic plants into areas outside their original distribution range and further settlement in natural ecosystems is not an exception in the Spanish Balearic archipelago. At the moment we have 308 non native species (naturalized and casual), the 16% from the total Balearic flora. This thesis has evaluated the exotic plant problematic at global and local level. We have elaborated the first exotic plants list, its distribution and abundance, as well as its degree of impact on the more vulnerable environments. We went deeply into the knowledge of two very invasive plants along the coast of the Balearic islands: Carpobrotus edulis y C. affine acinaciformis. We have evaluated its influence over pollen transmission, its growth rate at different environmental conditions, we have too elaborated a non liner growth model and its impact on composition and structure in natural communities

Page generated in 0.0591 seconds