THÈSE - Université de Franche-Comté

The sentence has been modified (page 7, line 193) and table 2 (page 23) has been
changed accordingly.
Comment 6 : As the authors themselves point out, a considerable proportion of the
variance in A. terrestris dynamics is not accounted for by the variables considered.
Consideration of alternative potential factors should be given more prominence in the
discussion.
Complementary information is now added in the revised manuscript (pages 14, lines 386-
392).
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Referee 2
Comment 1 : Only a small amount of the variation (< 30%) is explained by the four
variables examined. Furthermore, it is uncertain whether the effect of grassland
management and control of rodents on A. terrestris population dynamics significantly
affect the crop damage. If data on crop yield of the parcels are available it would
significantly improve the basis for the recommendations if crop yield was included in the
analysis. Otherwise this uncertainty should be highlighted in the manuscript.
Unfortunately, to date, no scientific studies have assessed the effects of rodents control on
crop yield. This is however an important issue which is uneasily addressed due to the
long duration of a small mammal cycle and heterogeneous damage and various impacts
on farm types. Gross statistics on damage costs generally comes from professionals and
the Ministry of Agriculture and are debatable. However, this information on the estimate
of financial losses have been included in the revised manuscript (page 3, lines 64-67).
They provide indication that grassland management could be cost-effective.
Comment 2 : Two Arvicola terrestris population variables were analysed (maximum and
delay; L 189). However, in 14 out of the 46 parcels examined it is questionable whether a
true maximum of the population was obtained, since the so-called maximum was
observed at the last data collection incidence in the study period (Fig 2).
Indeed, some study parcels showed the “maximum” at the last data collection in the study
period. We however think that, based on the theoretical duration of an entire cycle (5-6
years, the 4 year-study period coincided with the increase phase of an A. terrestris
population cycle).
Comment 3 : Interpretation of Fig 3 and Fig 4 are poorly (and insufficiently) explained
in the text. Results will be much more clear to the reader if the authors in short explain
how to read the important point of those two figures and thereby simultaneously clarify
the basis for their conclusions e.g. :
In Fig 3 by explaining the :
- meaning of lines pointing in the same vs. opposite direction,
July 05 A. terrestris and farming practices
C. Morilhat, N. Bernard, C. Bournais, C. Meyer, C. Lamboley and P. Giraudoux
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