Effects of Twenty Years of Ungulate Browsing on Forest Regeneration at Paneveggio Reserve, Italy

Round 1

Reviewer 1 Report

This paper deals with a long debated issue i.e. the impact of wild ungulates on forest with special reference to browsing activity. It is a clear and convincing piece of work with the main asset related to the long term evaluation of the impacts. Moreover, I appreciate the careful attention given to the differences among tree species in the susceptibility to ungulate browsing and its long term consequence. I have reported my comments on the annotated manuscript that I attach.

However, my main suggestion is to include ungulate numbers in different years as an independent variable in the model. It is in my opinion a pity not to quantify the impacts also in relation to browsers density, an information that I think is easily available for the Authors.

Comments for author File: Comments.pdf

Author Response

Dear reviewer,

We thank you for your comments and your suggestions. 

You can find a point by point response in the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Twenty years of ungulate browsing on Norway spruce forest regeneration at Paneveggio reserve, TN, Italy

 General comment- Authors used repeated forest inventories to examine patterns of browsing damage on regenerating trees in a northern Italian forest. In general, I found the manuscript to be convincing and data analyses appropriate. Authors argue that changes in community composition of saplings is largely due to increased browsing pressure by an expanding population of ungulates. As I mention below, it would be very helpful to provide additional evidence for this population increase so that readers have better grounds to see the connection. Also, should better clarify whether browsing affects differential mortality of trees, which then leads to changes in community composition, or if the trees of certain species (eg rowan) are simply stunted and not able to reach larger size classes.

Title- suggest that “Norway spruce” be dropped from the title (or perhaps just drop “Norway”) as numerous forest types seem to have been sampled

Abstract- line 23 and throughout paper- “regeneration” is treated as a noun here whereas more commonly seen as a verb or process. I suggest a different term for the saplings of different species found in each plot- or define the term upfront.

Line 30- “classes of plants”

Line 31-34- authors gave little to no information on changes in ungulate density in this paper- it seems very speculative to infer that changes in density could be responsible for patterns observed here unless they incorporate this better into the models

Introduction

Lines 45-47- The first sentence should distinguish between native and introduced ungulates. The latter would be a far bigger problem in terms of “troubling” species than the former

Line 54- drop the “s” on ungulates (should be singular)

Line 58- suggest changing sentence to “Therefore, there has been a large recent effort towards evaluating”… (suggest citation here also)

Line 62-67- Authors state here that many of the saplings included in this study may live up to 60 years. Authors should clarify here or in methods whether browsing is known to cause mortality of trees or if it primarily reduces growth.  

Line 73- this is a very abrupt jump to Italy. Clarification on why this forest in Italy is well-suited to addressing questions from this study would be helpful

Materials and Methods

Line 82- Site Characteristics- Authors mention in Intro that studies at larger spatial scales are needed but there is no indication here of the spatial scale of this study. What is the total area included in the survey and how far apart are the survey stations? A map with survey locations would be helpful

Line 91- It would be good to give a better description of each forest type- for example- what tree species make up the montane spruce forest? Also- should list species names in the methods, when their respective common names are referred to.

Line 95- more information on ungulate densities and changes over time in the area where the plots are located would be very helpful (for example, readers don’t know where Fassa, Fiemme, and Primiero districts are). Also- converting absolute numbers to densities per hectare would be much more informative.

Line 116-120- were measurements of damaged/undamaged for that season only, or could this have been damage from previous years?

Line 143- Table 1- not clear why IQR is presented as measure of dispersion instead of SD?

Line 149- need more info on “bearable limit”, especially because the reference appears to be in German.

Line 153- “except”

Line 165- “for either size class”

Discussion

Lines 188-192- It seems that the 3 species of herbivores would have different food preferences and also that there would be changes in relative abundance among the three species of herbivore between the time periods. For example, overall herbivore density may stay the same (or increase) over time, but the relative abundance of each species could vary dramatically. How would this affect results for browsing damage for each tree species? This again hi-lites my concern about lack of info on actual changes in herbivore density

Line 195- “we hypothesize also that the snowfalls that occurred”

Line 219- need citation for this sentence

Line 231- “due to the sensitivity”

Line 248- “many smaller trees”

Line 249- “to their greater richness”

Line 262- other factors could also include changes in relative abundance of the different ungulate species

Line 267- “is a long process”

Line 282- “consistent”

Conclusions

Much of the conclusions section is focused on the effects of ungulate overpopulation on browsing patterns. While this seems believable, authors need to present more evidence for patterns of increase of ungulates. Right now this evidence consists of a single sentence (99-101) for how red deer have increased from 2001 to 2019 in an area that may or may not be nearby this study area, as well as a reference in the first line of the discussion.

Author Response

Dear reviewer,

We are want to thank you for your comments and suggestions.

We have found them very useful in order to improve the quality of our paper.

You can find a poin by point response of your review in the attachment.

Author Response File: Author Response.pdf