Pollen limitation is not the rule in nival plants: A study from the European Central Alps

Wagner, Johanna; Lechleitner, Martin; Hosp, Daniela

doi:10.3732/ajb.1500214

Cited by 30 publications

(37 citation statements)

References 80 publications

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“…Although studies examining pollen limitation in natural plant populations are largely focused on pollination quantity, qualitative pollen limitation has been repeatedly highlighted as a critical factor limiting reproductive success (Aizen & Harder, ; Alonso, Herrera, & Ashman, ; Ashman & Morgan, ). In this regard, recent investigations are providing empirical support for the important role of pollen quality (Castilla, Alonso, & Herrera, ; Vaughton & Ramsey, ; Wagner, Lechleitner, & Hosp, ). Our results suggest that stigmas of P. bourgaeana flowers are receiving a substantial amount of either self‐ or genetically related pollen, which is qualitatively limiting their seed production.…”

Section: Discussionmentioning

confidence: 95%

Genetic rescue by distant trees mitigates qualitative pollen limitation imposed by fine‐scale spatial genetic structure

et al. 2019

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Restricted seed dispersal frequently leads to fine‐scale spatial genetic structure (i.e., FSGS) within plant populations. Depending on its spatial extent and the mobility of pollinators, this inflated kinship at the immediate neighbourhood can critically impoverish pollen quality. Despite the common occurrence of positive FSGS within plant populations, our knowledge regarding the role of long‐distance pollination preventing reproductive failure is still limited. Using microsatellite markers, we examined the existence of positive FSGS in two low‐density populations of the tree Pyrus bourgaeana. We also designed controlled crosses among trees differing in their kinship to investigate the effects of increased local kinship on plant reproduction. We used six pollination treatments and fully monitored fruit production, fruit and seed weight, proportion of mature seeds per fruit, and seed germination. Our results revealed positive FSGS in both study populations and lower fruit initiation in flowers pollinated with pollen from highly‐genetically related individuals within the neighbourhood, with this trend intensifying as the fruit development progressed. Besides, open‐pollinated flowers exhibited lower performance compared to those pollinated by distant pollen donors, suggesting intense qualitative pollen limitation in natural populations. We found positive fine‐scale spatial genetic structure is translated into impoverished pollen quality from nearby pollen donors which negatively impacts the reproductive success of trees in low‐density populations. Under this scenario of intrapopulation genetic rescue by distant pollen donors, the relevance of highly‐mobile pollinators for connecting spatially and genetically distant patches of trees may be crucial to safeguarding population recruitment.

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Section: Discussionmentioning

confidence: 95%

Genetic rescue by distant trees mitigates qualitative pollen limitation imposed by fine‐scale spatial genetic structure

et al. 2019

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“…In some alpine species, flower longevity compensation seems to work quite well (Bingham & Orthner, 1998;Pickering, 1997), but in others, as in the Andes, it is not fail-safe (e.g., Wu et al, 2015). Insects appear to be sufficiently abundant to enable good seed set on some high nival species in the European Alps (Wagner et al, 2016). Nevertheless, it would not be surprisingly that the abundant visitation recorded in this study is recent and due to global warming which is strongly elevation-dependent (Falvey & Garreaud, 2009;Gobiet et al, 2014;Pepin et al, 2015) and is occurring at a faster rate in the northern hemisphere (Friedman, Hwang, Chiang, & Frierson, 2013).…”

Section: R P Y G G a M S P M A D S A T H Y P T H R N A S Co M Chu Oppmentioning

confidence: 99%

“…Alpine areas and the Arctic thus are prime candidates for ovule bet-hedging (Burd et al, 2009). However, although the possibility of ovule oversupply has been mentioned by some authors (Fulkerson et al, 2012;Wagner, Lechleitner, & Hosp, 2016), no study has explicitly tested the ovule bet-hedging hypothesis in these harsh environments for animal pollinators.…”

Section: Introductionmentioning

confidence: 99%

Ovule bet‐hedging at high elevation in the South American Andes: Evidence from a phylogenetically controlled multispecies study

et al. 2018

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How animal‐pollinated plants support low and stochastic pollination in the high alpine is a key question in plant ecology. The ovule bet‐hedging hypothesis proposes compensation for stochastic pollination via ovule oversupply in flowers allowing the benefits of windfall pollination events to be reaped. Under this hypothesis, ovule number is expected to increase from tree line upward on high mountains characterized by steep declines in flower visitation rates and increasingly more variable pollination. Ovule/floret number was investigated for a total of 174 simple‐flowered and pseudanthial species in the central Chilean Andes (2,100–3,650 m.a.s.l.). Phylogenetic reconstruction was undertaken using ITS sequences and a constrained ordinal‐level backbone reflecting the APG‐IV topology. Ovule/floret number was modelled with ordinary least squares regression (OLS) and phylogenetic generalized least squares regression (PGLS) with elevation, floral biomass, life history, pollinator efficiency, pollination generalization, and seasonal flowering period as explanatory variables. The best performing OLS and PGLS models for simple‐flowered species consistently included vegetation belt and floral biomass, and with PGLS, pollination efficiency and flowering period. For pseudanthial species, explanatory variables were always floral biomass and its interaction with elevation. Effects of life history and generalized pollination was not found. Ovule/floret number showed high phylogenetic signal, increased with floral biomass and was generally higher in the upper alpine belt in both floral categories. Simple‐flowered species with efficient pollination and flowering early, respectively, had larger ovule numbers. Synthesis. Ovule number increases with elevation in the central Chilean alpine in two separate floral groups independently of some effects of flowering period and pollinator efficiency. Greater disparity in pollen deposition on stigmas than with inefficient pollination under low visitation rates might explain the association between efficient pollination and higher ovule numbers. Our study provides the first empirical evidence for ovule bet‐hedging in the alpine environment. Future studies on the ovule bet‐hedging hypothesis should include a measure of flower size.

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“…Altitudinal scale investigation can be a good proxy for inferring the impact of temperature change on pollinator assemblage and activity as temperature varies with elevation (Hegland et al 2009). Many researchers have reported that pollinator assemblages tend to change from bees at lower altitudes (Totland 1993;Hoiss et al 2012;Zhao and Wang 2015) to flies at higher altitudes (Arroyo et al 1982;Totland 1993;Lázaro et al 2008;Inouye et al 2015;Wagner et al 2016) and that their activity decreases with elevation (Arroyo et al 1985;Primack and Inouye 1993;Bingham and Orthner 1998;Zhao and Wang 2015). However, relatively few studies have focused on how temperature changes during a flowering season affect high-altitude plant-pollinator assemblage and activity (Primack 1978;Mizunaga and Kudo 2017).…”

Section: Introductionmentioning

confidence: 99%

Temperature-driven changes of pollinator assemblage and activity of Megaleranthis saniculifolia (Ranunculaceae) at high altitudes on Mt. Sobaeksan, South Korea

Lee

Kang

2018

j ecology environ

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Background: Temperature-driven variation in pollinator assemblage and activity are important information, especially at high altitudes, where rising temperature trends exceed global levels. Temporal patterns of pollinators in a flowering season can be used as a proxy to predict the changes of high-altitude plants' mutualistic relationships. We observed a spring temperature change in one population of a high-altitude endemic species, Megaleranthis saniculifolia on Mt. Sobaeksan, and related it to pollinator assemblage and activity changes. Methods: This study was conducted at two sites, each facing different slopes (NE and NW), for two times in the spring of 2013 (early-flowering, April 27-28, vs. mid-flowering, May 7-8, 2013). We confirmed that the two sites were comparable in snowmelt regime, composition of flowering plants, and flower density, which could affect pollinator assemblage and activity. Pollinator assemblage and activity were investigated at three quadrats (1 m 2 with 5-m distance) for each site, covering a total of 840 min observation for each site. We analyzed correlations between the temperature and visitation frequency.Results: Twelve pollinator species belonging to four orders were observed for M. saniculifolia at both sites during earlyand mid-flowering times. Diptera (five species) and hymenopteran species (four species) were the most abundant pollinators. Pollinator richness increased at both sites toward the mid-flowering time [early vs. mid = 7 (NE) and 3 (NW) vs. 9 (NE) and 5 (NW)]. Compared to the early-flowering time, visitation frequency showed a fourfold increase in the mid-flowering time. With the progression of spring, major pollinators changed from flies to bees. Upon using data pooled over both sites and flowering times, hourly visitation frequency was strongly positively correlated with hourly mean air temperature.Conclusions: The spring temperature change over a relatively brief flowering period of M. saniculifolia at high altitudes can alter pollinator assemblages through pollinator dominance and visitation frequency changes. Thus, this study emphasizes information on intra-and inter-annual variations in the mutualistic relationship between pollinators and M. saniculifolia to further assess the warming impacts on M. saniculifolia's reproductive fitness.

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Pollen limitation is not the rule in nival plants: A study from the European Central Alps

Abstract: Our results do not support the idea of chronic, widespread pollen limitation in the subnival but rather fit into the concept of parental optimism by overinvesting in the number of ovules as an adaptation to variable resource availability.

Cited by 30 publications

References 80 publications

Genetic rescue by distant trees mitigates qualitative pollen limitation imposed by fine‐scale spatial genetic structure

Genetic rescue by distant trees mitigates qualitative pollen limitation imposed by fine‐scale spatial genetic structure

Ovule bet‐hedging at high elevation in the South American Andes: Evidence from a phylogenetically controlled multispecies study

Temperature-driven changes of pollinator assemblage and activity of Megaleranthis saniculifolia (Ranunculaceae) at high altitudes on Mt. Sobaeksan, South Korea

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