https://www.uv.mx/personal/tcarmona/files/2010/08/De-Witte-y-Stocklin-2010.pdf

Longevity of clonal plants: why it matters and how to measure it.

Pre-dispersal seed predation may have important effects on population dynamics and trait evolution in plants. In this review, we first present a conceptual framework of the strength of pre-dispersal seed predation and its variation in space and time. We consider the interaction between plants and their seed predators to be “strong” when it affects plant population dynamics or causes changes in plant trait–fitness relationships, and “weak” when it has no such effects, and propose ways of how to adequately assess these effects. Second, we review the ecological literature between 1991 and 2005 to evaluate documented effects of pre-dispersal seed predation on plants and draw five major conclusions. (1) Pre-dispersal seed predation rates are usually low but sometimes high, and show a considerable variation in space and time. (2) Direct evidence suggests that pre-dispersal seed predation can have a significant effect on recruitment and plant population growth rate. Accumulating evidence of seed-limited recruitment suggests that such effects are common. (3) Pre-dispersal seed predation affects selection on several plant traits, such as flowering phenology and flower number, which are usually interpreted mainly in the context of plant–pollinator interactions. (4) The patterns of variation in the interactions between plants and pre-dispersal seed predators suggest that geographic selection mosaics may be common. (5) Although there are numerous studies estimating seed predation, there are still rather few studies that have aimed at examining the interaction explicitly in terms of effects on plant population dynamics and trait selection. From these we know that seed predators can have important, and often variable, effects on plant population dynamics and trait evolution. However, it still remains to assess how important they are across study systems and relative to other aspects of the plant's biotic and abiotic environment.

Ecological and evolutionary consequences of spatial and temporal variation in pre-dispersal seed predation

Mountain regions and UNESCO Mountain Biosphere Reserves (MBRs) encapsulate broad elevational ranges, cover large gradients of geological, topographical and climatic diversity, and thus host greater biodiversity than the surrounding lowlands. Much of the biological richness in MBRs results from the interaction of climatic contrasts and gravitational forces along elevational gradients. External forces such as atmospheric change and human land use interact with these gradients, and result in distinct landscape patchiness, ie mosaics of land cover types within and across elevational belts. The management of MBRs influences land use and land cover, which affects biodiversity and ecosystem processes, both of which provide goods and services to society. Due to their broad environmental and biological diversity, MBRs are ideally suited for global change research and will be increasingly important in illustrating biodiversity conservation. This article summarizes the ecologically relevant results of an in...

/pdf/ecological-and-land-use-studies-along-elevational-gradients-56ises730n.pdf

Ecological and Land Use Studies Along Elevational Gradients

Withstanding extinction while facing rapid climate change depends on a species' ability to track its ecological niche or to evolve a new one. Current methods that predict climate-driven species' range shifts use ecological modelling without eco-evolutionary dynamics. Here we present an eco-evolutionary forecasting framework that combines niche modelling with individual-based demographic and genetic simulations. Applying our approach to four endemic perennial plant species of the Austrian Alps, we show that accounting for eco-evolutionary dynamics when predicting species' responses to climate change is crucial. Perennial species persist in unsuitable habitats longer than predicted by niche modelling, causing delayed range losses; however, their evolutionary responses are constrained because long-lived adults produce increasingly maladapted offspring. Decreasing population size due to maladaptation occurs faster than the contraction of the species range, especially for the most abundant species. Monitoring of species' local abundance rather than their range may likely better inform on species' extinction risks under climate change.

https://www.zora.uzh.ch/id/eprint/137255/1/CottoEtal_2017_NComms15399.pdf

A dynamic eco-evolutionary model predicts slow response of alpine plants to climate warming

Plant survival in alpine landscapes is constantly challenged by the harsh and often unpredictable environmental conditions. Steep environmental gradients and patchy distribution of habitats lead to small size and spatial isolation of populations and restrict gene flow. Agricultural land use has further increased the diversity of habitats below and above the treeline. We studied the consequences of the highly structured alpine landscape for evolutionary processes in four study plants: Epilobium fleischeri, Geum reptans, Campanula thyrsoides and Poa alpina. The main questions were: (1) How is genetic diversity distributed within and among populations and is it affected by altitude, population size or land use? (2) Do reproductive traits such as allocation to sexual or vegetative reproduction vary with altitude or land use? Furthermore, we studied if seed weight increases with altitude. Within-population genetic diversity of the four species was high and mostly not related to altitude and population size. Nevertheless, genetic differentiation among populations was pronounced and strongly increasing with distance. In Poa alpina genetic diversity was affected by land use. Results suggest considerable genetic drift among populations of alpine plants. Reproductive allocation was affected by altitude and land use in Poa alpina and by succession in Geum reptans. Seed weight was usually higher in alpine species than in related lowland species. We conclude that the evolutionary potential to respond to global change is mostly intact in alpine plants, even at high altitude. Phenotypic variability is shaped by adaptive as well as by random evolutionary processes; moreover plastic responses to growth conditions seem to be crucial for survival of plants in the alpine landscape.

/pdf/genetic-diversity-phenotypic-variation-and-local-adaptation-5bseop4hvn.pdf

Genetic diversity, phenotypic variation and local adaptation in the alpine landscape: case studies with alpine plant species

1 Demographic studies in natural habitats are important for understanding the life history and mechanisms of population persistence of particular species. For plants living in high-alpine habitats, it is of significant importance to what extent sexual or clonal reproduction contribute to population growth, but respective data are scarce. 2 We studied the demography of Geum reptans, an alpine plant which reproduces by seeds and by vegetative rosettes formed at the ends of above-ground stolons. In three consecutive years, growth, survival, and reproduction were measured in two populations with 579 and 301 individuals, respectively. The two resulting transition matrices per population were used to calculate population growth rates (lambda) and elasticities, and to perform stochastic simulations to assess the relative importance of sexual vs. clonal reproduction for population growth. 3 Population growth rates (lambda) varied from 0.999 to 1.074 among years and populations. The frequency of seed and stolon production was relatively constant over the years. However, there was interannual variation in seed germination (0.7-2.4 clonal offspring (53-74 4 Elasticity analysis showed that changes in the survival of adults had the largest effect on lambda, confirming the importance of longevity and persistence in the life history of G. reptans. 5 Stochastic simulations showed that in G. reptans, independently of location and year, both sexual and clonal reproduction did not significantly differ in their contribution to the population growth rate lambda. Establishment from seeds contributes to population growth particularly in favourable years, while the more regularly occurring reproduction by clonal offspring may ensure population growth in less favourable years. 6 Sexual reproduction in clonal plants is frequently explained by the short- and long-term benefits of genetic variation and the need for dispersal and colonization, for which seeds are better suited than vegetative organs. Our results, however, show the importance of sexual reproduction in a clonal plant for local dynamics as well, and prove the power of matrix models to evaluate the relative contributions of the two reproductive modes.

The relative importance of sexual and clonal reproduction for population growth in the long-lived alpine plant Geum reptans

Variation of sexual and clonal reproduction in the alpine Geum reptans in contrasting altitudes and successional stages

We studied the impact of the seed damaging gall midge larva Geomyia alpina on its perennial alpine host plant Geum reptans. We analysed the effect of seed predation on reproduction by seeds, i.e. seed number, seed mass, and seed viability and on growth and clonal propagation of non-protected plants in comparison to plants protected from predation by an insecticide. Additionally, we assessed the consequences of seed predation for population growth using matrix projection modelling. Seed predation resulted in a decrease in total seed mass per flower head by 23.8% in non-protected plants (P < 0.05). Individual seed mass decreased with increasing infestation intensity (P < 0.05). Seed number remained unaffected because the sucking feeding behaviour by gall midge larvae does not evoke seed abortion. Percent germination of seeds from non-protected plants was reduced by 97.9% compared to seeds from protected plants. According to reduced seed viability, modelling revealed a decrease in population growth rate from λ = 1.055 to λ = 1.041. Predation did neither influence total plant biomass nor biomass fractions. But stolon dry-weight of non-protected plants increased by 24.1% (P < 0.05), which may indicate a trade-off between sexual reproduction and clonal propagation. Our results demonstrate that despite substantial reduction of viable seeds, predation by gall midge larvae only slightly affected population growth of G. reptans suggesting that in this alpine species, persistence by longevity and clonal propagation can balance potential seed losses by predation, at least for local population growth.

/pdf/does-pre-dispersal-seed-predation-limit-reproduction-and-s08covj4ra.pdf

Tina Weppler

Papers

The relative importance of sexual and clonal reproduction for population growth in the long-lived alpine plant Geum reptans

Variation of sexual and clonal reproduction in the alpine Geum reptans in contrasting altitudes and successional stages

Does pre-dispersal seed predation limit reproduction and population growth in the alpine clonal plant Geum reptans?