General comments:
This paper describes the use of a large-scale dataset to explore temporal trends in vascular plant species distributions in the French alps over the last 30 years and to relate trends to species’ characteristics. I found the paper to be extremely well written – the text clearly sets out the background and rationale for the study, the methods are well explained and the results clearly presented. I had a few minor comments and questions which are detailed below. My only significant query related to Fig 4C where the text did not seem to fit the data presented in the figure for the relationship between herb and tree temporal trends and plant height – this requires some clarification.
Overall, I found the paper to be very interesting, it does a great job of deriving species’ temporal trends in a statistically robust way and accounting for the biases which are common in the datasets used for these types of studies. It was also good to see efforts being made to include insights from the community of field botanists. The paper provides an important insight into the distribution of temporal trends across a significant part of the French flora which occurs in the alpine region and also into the extent to which this relates to, and can be predicted by, species traits and characteristics.
Specific comments:
Methods
Ln 155 – It would be helpful to specify here if the dataset covers vascular plants only.
Ln 186 – This is the first mention of a subset of ‘focal species’ – how were they selected?
Ln 188 – ‘the most IUCN regional…’ is there a word missing here?
Ln 209 – LMA has not been defined
Ln 218 – Is Androsase spelled correctly?
Ln 258 – This explanation of the model could be clearer – is Y representing the species response? And why is Y~Year only described as non-significant change? Surely this could also imply a significant positive or negative relationship between Y and year – which seems to be the case from the subsequent explanation.
Ln 262- What happens if a species shows an inconsistent but significant trend through time e.g. increase and then decrease? Is this counted as non-significant change?
Ln 263 – Full stop missing after stable.
Results
Ln 372 – Full stop missing after trends.
Ln 389 – The relationship between temporal trend and plant height given in the text seems to be the opposite of what is shown in Fig 4C, where there is a negative trend for trees and a positive trend for herbs – is something wrong here? I was also not greatly convinced about the relationships between SLA and trend for shrubs and herbs - the regression line for the herbs, seems to fluctuate around zero and I wouldn’t say it was a convincing positive relationship as described in the text.
Ln 405 – I think it would be helpful to include one of these figures (either S5 or S6) in the main text for ease of reference when reading the results.
Discussion.
Ln 428 – it would be clearer if you inserted ‘of the total’ after 13%. Also ‘so’ should be ‘though’.