add new soil moisture x phenology refs

[lizzieinvancouver]

I am assuming that I checked refs back in 2022 so I will check for refs 2022 onward mostly (including 2022). Here's what I have done using Web of Science. I searched using: soil moisture AND phenolog* then looked at the hot and highly cited through 2020 and all the papers from Jan 2022 onward ...

• Summer soil drying exacerbated by earlier spring greening of northern vegetation -- by Lian, this paper uses observational data to say that earlier phenology drives lower soil moisture, which I think is good to connect to point out that we need experiments to better tease out these possible feedbacks.
• Global analysis of time-lag and -accumulation effects of climate on vegetation growth -- and many more remote sensing papers like this (i.e., focused on on observational data, ML or similar approaches and using some sort of remote sensing product) we could find if we wanted
• Land surface phenology as indicator of global terrestrial ecosystem dynamics: A systematic review -- good review paper that says soil moisture appears to matter to phenology and people should use land surface data more to look at this (they only say soil moisture ONCE more beyond the abstract though in a preprint I found online).

Then I subsetted to 2022-2024 and confined search to: soil moisture AND phenolog (All Fields) and flower OR spring OR budburst OR leaf* (All Fields) ... this led to 214 papers, of which I looked at the 50 most relevant (as they got increasingly less relevant quickly).

• Overview: here are a LOT of crop papers and a lot of remote sensing papers.
• Soil moisture determines the effects of climate warming on spring phenology in grasslands -- drying delayed SOS
• Earlier leaf senescence dates are constrained by soil moisture -- could be useful if we want to say there is growing interest in moisture and phenology (`Our study therefore reveals the importance of soil moisture in regulating autumn LSD and, in particular, highlights how coupling this effect with LSD models can improve simulations of the response of vegetation phenology to future climate change.')
• Soil temperature dominates forest spring phenology in China -- especially useful I think, as they show warming effects soil moisture and maybe then phenology, but only observationally ... `The SEM further demonstrated that ST is the dominant factor in SOS variability, moreover, ST not only directly affects SOS, but also indirectly affects the SOS by influencing the soil moisture. These findings highlight the key role of ST in regulating changes in forest spring phenology in China, which is absent in most phenology models but should be considered when predicting forest phenology and associated carbon budgets.;

Then I looked at the top 50 refs (2022-2024) for: precipitation AND phenolog (All Fields) and flower OR spring OR budburst OR leaf* (All Fields)

• Overview: here are a LOT of experiments on precipitation (and temperature) on phenology in China (especially Tibetan Plateau).
• Precipitation versus temperature as phenology controls in drylands - -If we wanted to cite a new-ish paper when we say phenology x precip is commonly studied in gasslands, also this paper finds what we find: `Pre-season drought strongly resulted in delayed grass greenup dates and shorter growing-season lengths.'
• Contrasting responses of early- and late-season plant phenophases to altered precipitation -- especially useful`Here, we conducted a meta-analysis of the responses of ten phenophases to altered precipitation from 63 manipulative experiments. We show that early-season (leaf out, first flowering, last flowering and first fruiting) and late-season phenophases (last fruiting and leaf colouring) shifted in opposite directions with precipitation changes. Advanced early-season phenophases and delayed late-season phenophases led to extensions of the reproductive phase and growing season with precipitation increases. Similarly, delayed leaf out and advanced leaf colouring resulted in a shorter length of the growing season with precipitation decreases. We further found that the responses of phenophases were less pronounced in wetter regions than in drier regions, regardless of the precipitation increase or decrease treatments.'
• Effects of drought on grassland phenology depend on functional types -- Sherry found earlier shifts earlier and later shifts later, this is another example of that: `We examine the effects of precipitation for species, functional types, and the community. Our results provide evidence that reduced precipitation shifts phenology, alters flower and fruit production, and that the magnitude and direction of the responses depend on functional type and species. For example, early-blooming species shift toward earlier flowering, whereas later-blooming species shift toward later flowering. Because of opposing species-level shifts, there is no overall shift in community-level phenology.' ... and makes me think we should discuss how our results compare in the discussion
• Decreasing temperature sensitivity of spring phenology decelerates the advance of spring phenology in northern temperate and boreal forests ... confusing but maybe relevant
• China's subtropical deciduous plants are more sensitive to climate change than evergreen plants by flowering phenology -- but `Conversely, the phenological change of evergreen plants in response to decreasing precipitation was greater than that of deciduous ones. '
• Climate warming interacts with other global change drivers to influence plant phenology: A meta-analysis of experimental studies -- we should cite this

[AileneKane]

Lizzie will write some sentences and add bib file on these for Ailene to integrate into Intro and Discussion

[lizzieinvancouver]

All citations are in fromLizzie2024.bib just now.

We may want to add to intro (or discussion) something like:

Increasing research using large-scale observational phenology data (e.g., remote sensing products such as NDVI) have documented an important role for soil moisture from forests to grasslands \citep{lian2020summer,shen2022plant,liu2024soil}, and suggested temperature may play a role through moderating soil moisture \citep{liu2024soil}. Teasing out the role of soil moisture from temperature is challenging through long-term climate trends alone, however....

We probably should acknowledge somewhere (we may already do this and could just tweak to these refs) the prevalence of precipitation manipulation experiments:

Many experiments have now focused on the effects of altered precipitation regimes, with meta-analyses highlighting the diversity of findings \citep{lu2023contrasting}, and the importance of interactive effects of precipitation shifts with global change drivers \citep{zhou2023climate}. In particular, recent work \citep{zhou2023climate} suggests warming combined with drought treatments may slow advances in phenology.

It may be worth adding in the intro/discussion something like: While increasing large-scale research suggests an important role for soil moisture in phenology, and small-scale experiments have found impacts of precipitation on phenology, there has been little work to understand cross-site impacts of soil moisture from experiments, despite the reality that many experiments collect these data.

[lizzieinvancouver]

From \citep{zhou2023climate}:

We found that increased precipitation advanced leaf out, first flowering and fruiting (Figures 2a–c), which could be related to the relief of water deficiency resulting from increased precipitation for leaf out and onset of flowering and fruiting that require a large amount of water (Arfin Khan et al., 2018; Ji et al., 2019). Delayed leaf out and first flowering and advanced leaf colouring induced by decreased precipitation were found in our study (Figure 2a–d). Decreased precipitation could cause a water deficit, and thus shorten the growing season, which is consistent with a recent meta-analysis (Lu et al., 2023). Interestingly, increased precipitation did not delay leaf colouring (Figure 2d) despite improved water availability. Thus, the effects of increased and decreased precipitation are not simple inverses.

[AileneKane]

@AileneKane will add these to the manuscript