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Unisexual bryophytes provide excellent models to study the mechanisms that regulate the frequency of sexual versus asexual reproduction in plants, and their ecological and evolutionary implications. Here, we determined sex expression, phenotypic sex ratio, and individual shoot traits in 242 populations of the cosmopolitan moss Pseudoscleropodium purum spanning its whole distributional range. We tested whether niche differentiation, sex-specific differences in shoot size, and biogeographical history explained the spatial variation of reproductive traits. We observed high levels of sex expression and predominantly female-biased populations, although both traits showed high intraspecific variation among populations. Sex expression and sex ratio were partly explained by current macroscale environmental variation, with male shoots being less frequent at the higher end of the environmental gradients defined by the current distribution of the species. Female bias in population sex ratio was significantly lower in areas recolonized after the last glacial maximum (recent populations) than in glacial refugia (long-term persistent populations). We demonstrated that reproductive trait variation in perennial unisexual mosses is partially driven by macroscale and historical environmental variation. Based on our results, we hypothesize that sexual dimorphism in environmental tolerance and vegetative growth contribute to sex ratio bias over time, constraining the chances of sexual reproduction, especially in long-term persistent populations. Further studies combining genetic analyses and population monitoring should improve our understanding of the implications of the intraspecific variation in the frequency of sexual versus asexual reproduction in bryophyte population fitness and eco-evolutionary dynamics., We are thankful to Bieito Rodríguez for sampling Azores Islands and to Alžběta Manukjanová for helping with the sampling in the Czech Republic. M.T. Boquete is supported by the Juan de la Cierva-Incorporación program from the Spanish Ministry of Science, Innovation and Universities (IJC2018-035018-I). J. Patiño was funded by the Support provided by the MINECO through the Juan de la Cierva-Incorporación program (IJCI- 2014-19691), the European Union through a Marie Sklodowska-Curie COFUND, Researchers' Night and Individual Fellowships Global (MSCA grant agreement No 747238, “UNISLAND”), and the MICINN through the Ramón y Cajal program (RYC-2016-20506). Z. Varela was supported by a postdoctoral research grant awarded by the Autonomous Government of Galicia (Spain). N. Cronberg was supported by Biodiversity and Ecosystem Services in a Changing Climate (BECC). J. Martínez-Abaigar and E. Núñez-Olivera were supported by European Regional Development Fund (ERDF/FEDER), the Spanish Ministry of Science and Innovation, and the Spanish Agencia Estatal de Investigación (Project PGC2018-093824-B-C42). R. Cruz de Carvalho was supported by a postdoctoral research grant from the project MedMossRoofs (PTDC/ATP-ARP/5826/2014) funded by the Foundation for Science and Technology (FCT, Portugal). C. Aleixo was supported by the FCT through a PhD grant (SFRH/BD/141822/2018).

International audience; Bryophytes have been proposed as ideal indicators of ecosystem change, because they are important components of forest integrity, and considerable research indicates that some groups are sensitive to the changes associated with specific human disturbances. Bryo-phyte richness and abundance have been found to vary predictably along elevational gradients , but the role of human impacts on these distribution patterns remains unclear. The aim of this study is to explore the impact of human disturbance on the elevational patterns of bryophyte diversity, along an elevational gradient. Along the gradient we collected three datasets in the following sites: preserved (P), forest track roadsides (R) and disturbed by agriculture/silviculture practices (D). Two survey plots of 100 m 2 were established at every 200 m elevational step for each sites P, R, D, and in each plot bryophytes were sampled in a stratified manner. At each plot we recorded all species on available substrates and estimated their percentage cover. Our results showed that species number did not differ among studied sites, but that species diversity pattern differs among the three gradient types and species life strategy composition along the elevational gradient showed a clear response to the disturbance of mature communities. We conclude that human impact has strongly changed the elevational pattern of diversity, and that these changes vary depending on the ecological and taxonomical group considered.

S1. Graph showing climate space of Tenerife. S2. Table of ecosystems on Tenerife. S3. Correction function applied to rabbit density estimation. S4. Conceptual path diagram for the structrual equation model. S5. Table of the standardized effects of structural equation model output. S6. Generalized limear mixed effects model; S7. Dataset of all abiotic and biotic data used in this study

Las islas Canarias forman parte de uno de los 25 puntos calientes de biodiversidad del planeta. Los ecosistemas insulares canarios presentan, por lo general, una elevada proporción de especies endémicas terrestres (680 taxones endémicos de plantas vasculares, que representan más del 50% del total de la flora nativa; cf. Reyes-Betancort et al., 2008). Desgraciadamente, los ecosistemas de las islas son muy frágiles y sensibles a cualquier tipo de alteración

Trabajo presentado en el II International Conference on Island Evolution, Ecology and Conservation, celebrado en Angra do Heroísmo, Islas Azores (Portugal) del 18 al 22 de julio de 2016., The European rabbit, Oryctolagus cuniculus, is an invasive mammal in the Canary Islands and a keystone species in alteration of island ecosystems worldwide. It may dramatically affect the vegetation through different mechanisms, and therefore contribute to modifying habitat and communities, producing benefits in some species and damaging others. Thus, the rabbit might be considered as an ‘ecosystem engineer’. Through a study on the population structure of the endemics shrubs Spartocytisus supranubius and Pterocephalus lasiospermus, we explored the role of rabbits as a keystone in driving changes on dominant species of the summit vegetation of El Teide National Park (Tenerife, Canary Islands). We also analysed the spatial heterogeneity of these two dominant species, their relation with the herbivores, the plant age-classes and the growth response to variation in soil nutrient availability. For these purposes 90 plots were established at 30 localities within the high mountain area. Furthermore, we used 13 permanent plots in two types of herbivore exclusions (‘only big-herbivores’ and ‘all herbivores’). In one of the localities, 100 soil samples were collected to analyse the relationship between changes in nutrients (N, NO3, K) produced by rabbits and plant growth. The population of S. supranubius is clearly declining due to the negative effect of rabbits in its regeneration, matching with a rapid increase in the population of P. lasiospermus. This study also showed that the density of rabbits is the most influential variable affecting the population structure of S. supranubius. Furthermore, the increase in nitrates and potassium favour the growth of P. lasiospermus. The high contrast in palatability between both species and the different response to the increase in nitrates and potassium, represent the main forces in explaining the current dynamic of the vegetation in the high mountain of Tenerife. Our results highlight the urgency to control the great density of rabbits in this area.

Trabajo presentado en Floramac celebrado en Las Palmas de Gran Canaria (España) del 24 al 27 de marzo de 2015., The European rabbit, Oryctolagus cunniculus, may dramatically affect the vegetation through different mechanisms, and therefore may contribute to modify habitat and communities, producing benefits in some species and harming others. Thus, rabbit might be considered as a landscape engineer. The European rabbit is an invasive mammal in the Canary Islands, and a keystone species in the change of the ecosystems. Some studies have shown the effects of this herbivore on some threatened species, but they do not have analysed its wide scale effects on dominant species of the Canary ecosystems. Here, we have explored the role of rabbits as ecosystem engineers in the summit vegetation of the Canary Islands, through a study on the population structure of Spartocytisus supranubius and Pterocephalus lassiospermus. We have studied the spatial heterogeneity of these two dominant species and the relationship between rabbit density and age-classes. For this purpose 90 analysis plots were established along 30 localities, within the distributional area of S. supranubius. Furthermore, we used 12 permanent plots of herbivore exclusion controlled by Teide National Park. In all of them the structure and composition of vegetation, as well as the most important abiotic variables, were analyzed. This study showed that density of rabbits is the most influential variable on the population structure of S. supranubius. It also confirmed that the population of the broom scrub is declining due to the negative effect of rabbits in its regeneration and showed that the decline of S. supranubius was positively correlated with the increase of P. lasiospermus.