Growth strategies and threshold responses to water deficit modulate effects of warming on tree seedlings from forest to alpine

Lazarus, Brynne E.; Castanha, Cristina; Germino, Matthew J.; Kueppers, Lara M.; Moyes, A. B.

doi:10.1111/1365-2745.12837

Cited by 42 publications

(35 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…, Lazarus et al. ). Initially, tree seedlings must establish and survive with little accumulated carbon ̶ there is small margin for error (Johnson et al.…”

Section: Discussionmentioning

confidence: 99%

“…Douglas‐fir also produce relatively large seeds, compared to lodgepole pine, which provides seedlings with greater carbohydrate reserves (Moles and Westoby , Lazarus et al. ).…”

Section: Discussionmentioning

confidence: 99%

“…Seedling establishment and survival are colimited by cold temperature and soil moisture, which declines with hot temperatures in subalpine forests. The effects of climate change on postfire tree regeneration will thus emerge from complex tradeoffs between warming and drying at fine spatial and temporal scales (Anderson-Teixeira et al 2013, Kroiss and HilleRisLambers 2015, Kueppers et al 2017, Lazarus et al 2018. Initially, tree seedlings must establish and survive with little accumulated carbon ̶ there is small margin for error (Johnson et al 2011).…”

Section: Climate Thresholds Of Tree Regenerationmentioning

confidence: 99%

See 2 more Smart Citations

Origins of abrupt change? Postfire subalpine conifer regeneration declines nonlinearly with warming and drying

Hansen

Turner

2019

Ecological Monographs

View full text Add to dashboard Cite

Robust tree regeneration following high‐severity wildfire is key to the resilience of subalpine and boreal forests, and 21st century climate could initiate abrupt change in forests if postfire temperature and soil moisture become less suitable for tree seedling establishment. Using two widespread conifer species, lodgepole pine (Pinus contorta var. latifolia) and Douglas‐fir (Pseudotsuga menziesii var. glauca), we conducted complementary experiments to ask (1) How will projected early‐ to mid‐21st‐century warming and drying affect postfire tree seedling establishment and mortality? (2) How does early seedling growth differ between species and vary with warming and drying? With a four‐year in situ seed‐planting experiment and a one growing season controlled‐environment experiment, we explored effects of climate on tree seedling establishment, growth, and survival and identified nonlinear responses to temperature and soil moisture. In our field experiment, warmer and drier conditions, consistent with mid‐21st‐century projections, led to a 92% and 76% reduction in establishment of lodgepole pine and Douglas‐fir. Within three years, all seedlings that established under warmer conditions died, as might be expected at lower elevations and lower latitudes of species’ ranges. Seedling establishment and mortality also varied with aspect; approximately 1.7 times more seedlings established on mesic vs. xeric aspects, and fewer seedlings died. In the controlled‐environment experiment, soil temperatures were 2.0°–5.5°C cooler than the field experiment, and warming led to increased tree seedling establishment, as might be expected at upper treeline or higher latitudes. Lodgepole pine grew taller than Douglas‐fir and produced more needles with warming. Douglas‐fir grew longer roots relative to shoots, compared with lodgepole pine, particularly in dry soils. Differences in early growth between species may mediate climate change effects on competitive interactions, successional trajectories, and species distributions. This study demonstrates that climate following high‐severity fire exerts strong control over postfire tree regeneration in subalpine conifer forests. Climate change experiments, such as those reported here, hold great potential for identifying mechanisms that could underpin fundamental ecological change in 21st‐century ecosystems.

show abstract

“…, Lazarus et al. ). Initially, tree seedlings must establish and survive with little accumulated carbon ̶ there is small margin for error (Johnson et al.…”

Section: Discussionmentioning

confidence: 99%

“…Douglas‐fir also produce relatively large seeds, compared to lodgepole pine, which provides seedlings with greater carbohydrate reserves (Moles and Westoby , Lazarus et al. ).…”

Section: Discussionmentioning

confidence: 99%

Section: Climate Thresholds Of Tree Regenerationmentioning

confidence: 99%

See 1 more Smart Citation

Origins of abrupt change? Postfire subalpine conifer regeneration declines nonlinearly with warming and drying

Hansen

Turner

2019

Ecological Monographs

View full text Add to dashboard Cite

show abstract

“…Warming interacted in eight observations (of 23 studies) with another factor’s effect on tree seedling growth (Table ). Seedling growth of four coniferous tree species responded more positively to warming in combination with watering, suggesting that they became water limited under warmed conditions (Lazarus, Castanha, Germino, Kueppers, & Moyes, ; Moyes et al., ). So although water did not affect growth in the single‐factors meta‐analysis, its importance for moderating warming responses should be pointed out.…”

Section: Relative Importance and Interactions Of Environmental Factorsmentioning

confidence: 99%

Global drivers of tree seedling establishment at alpine treelines in a changing climate

Lett

Dorrepaal

2018

Functional Ecology

View full text Add to dashboard Cite

Alpine and Arctic treeline expansion depends on establishment of tree seedlings beyond the current treeline, which is expected to occur with climate warming. However, treelines often fail to respond to higher temperatures, and it is therefore likely that other environmental factors are important for seedling establishment. We aimed to analyse our current understanding of how temperature and a range of other environmental drivers affect tree seedling establishment at the alpine and Arctic treelines world‐wide and to assess the relative importance of temperature compared with other factors and how they interact. We collected 366 observations from 76 experimental and observational papers for a qualitative analysis of the role of a wide range of environmental factors on tree seed germination, tree seedling growth, survival and natural occurrence. For a subset of these studies, where the experimental design allowed, we conducted formal meta‐analyses to reveal if there were global drivers for different seedling life traits. The analyses showed that a wide range of abiotic and biotic factors affected tree seedling establishment besides from temperature, including water, snow, nutrients, light and surrounding vegetation. The meta‐analyses showed that different seedling life stages do not respond similarly to environmental factors. For example, temperature had positive effects on growth, while tree seedling survival and germination showed mixed responses to warming. Further, warming was as often as not the strongest factor controlling tree seedling establishment, when compared to with one of five other environmental factors. Moreover, warming effects often depended on other factors such as moisture or the presence of surrounding vegetation. Our results suggest that population dynamics of trees at the alpine and Arctic treeline is responsive to environmental changes and show that there is a clear need for multifactorial studies if we want to fully understand and predict the interplay between warming and other environmental factors and their effect on tree seedling establishment across current treelines. A http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.13137/suppinfo is available for this article.

show abstract

“…Most tree species do not maintain a long-lived seed bank, and abundant seed production does not begin until individuals are large Shepperd 1984, Burns andHonkala 1990). In addition to these biotic effects, the removal of closed, continuous canopies also connects the macroclimate to the microclimate affecting understory environmental conditions (Carlson and Groot 1997, Gray et al 2002, Lazarus et al 2018. In addition to these biotic effects, the removal of closed, continuous canopies also connects the macroclimate to the microclimate affecting understory environmental conditions (Carlson and Groot 1997, Gray et al 2002, Lazarus et al 2018.…”

Section: Introductionmentioning

confidence: 99%

Epidemic spruce beetle outbreak changes drivers of Engelmann spruce regeneration

et al. 2019

View full text Add to dashboard Cite

Climate-mediated disturbances outside the range of historical variability can have severe consequences on vital, post-disturbance regeneration processes. High-elevation forests of the Rocky Mountains that are dominated by Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) are expected to be sensitive to climate change. Additionally, these forests have experienced recent epidemic spruce beetle (Dendroctonus rufipennis) outbreaks that have often resulted in >95% mortality of overstory Engelmann spruce. Therefore, the future distribution of Engelmann spruce forests depends largely on natural regeneration processes. We examined Engelmann spruce seedlings across gradients in soil moisture and stand structural conditions 20 yr post-disturbance on the Markagunt Plateau in southern Utah. All Engelmann spruce seedlings were mapped, measured, and aged, and aspects of stand structure and the microclimate were measured. The goal of our research was to infer processes affecting Engelmann spruce establishment by determining if patterns of advance regeneration that established before the outbreak (~60% of individuals) differed from seedlings that established during and immediately following the outbreak (combined into one group,~40% of individuals). A generalized linear multi-model approach identified that the density of advance regeneration (seedlings/saplings) was negatively influenced by historical competition with overstory trees. In contrast, post-outbreak regeneration was related to microclimate conditions, including positive relationships with climatic moisture deficit and July soil water content. All seedlings were not significantly clustered around Engelmann spruce snags; however, there was evidence of facilitation of post-outbreak seedlings by pre-outbreak seedlings at higher elevation sites with lower moisture deficit. Together, these findings suggest post-outbreak seedlings were not moisture-limited at lower elevations but instead encouraged by higher evapotranspiration. Moreover, facilitation at higher elevations likely resulted from how pre-outbreak seedlings modify snowpack and associated seedbed environments. Our study provides insight for managing Engelmann spruce after a beetle outbreak. In these forests, pre-and post-outbreak regeneration can increase resilience to climate-disturbance interactions, but are patchy and structured at different scales. Therefore, the presence of advance regeneration and the likelihood of post-outbreak seedlings depend on local environment (soil moisture and stand structure) and could be taken into account to most effectively plan post-disturbance planting activities.

show abstract

Growth strategies and threshold responses to water deficit modulate effects of warming on tree seedlings from forest to alpine

Cited by 42 publications

References 51 publications

Origins of abrupt change? Postfire subalpine conifer regeneration declines nonlinearly with warming and drying

Origins of abrupt change? Postfire subalpine conifer regeneration declines nonlinearly with warming and drying

Global drivers of tree seedling establishment at alpine treelines in a changing climate

Epidemic spruce beetle outbreak changes drivers of Engelmann spruce regeneration

Contact Info

Product

Resources

About