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elationship between the vegetation dynamics and the outbreak intensity (activity rate) of vole populations, Kopp (1993) showed that outbreaks lead to higher population densities in agricultural parcels offering better plant cover. These studies suggested that farming practices influenced the water vole populations, via habitat modifications. However, to our knowledge, no quantitative studies have determined the effects of farming practices on the water vole populations on a parcel scale. Delattre et al. (submitted) showed that, for the same area, there can be as many as 16 to 38 times more new vole colonies within the mole networks than outside them. Thus, on a parcel scale, mole gallery networks may play an important role in the growth of vole colonies in the early stages of vole population increase. This phenomenon could be related to the use of available T. europaea gallery networks by A. terrestris (Meylan & Höhn 1991) and could explain the faster colonisation by A. terrestris populations under such conditions. This observation, to date, has never been taken into account in other studies. The aim of this study was to test the hypothesis of an impact of farming practices upon the population dynamics of the water vole on a parcel scale. We examined the effect of farming practices on the water vole populations during two parts of an A. terrestris population cycle: the low density phase and the increase phase and the high density phase. A wide spectrum of farming practices are generally considered to be important for small mammal population dynamics (Jacob & Hempel 2003). In this study, we focused on fertilisation, mowing and disturbances caused by soil work (ploughing, stamping by cattle, etc…). We specifically analysed the impact of grazing and soil work on the water vole relative abundance at the high density phase of a cyclic outbreak and, took into account mole population abundance. Our results are discussed in relation to grassland management practices in temperate ecosystems and their implications for the prevention of rodent outbreaks. Material and methods STUDY SITES Grassland parcels were selected in 21 communes of the Doubs and the Jura departments (French administrative divisions - 47.11°N, 6.24°E) (Fig. 1). In these departments, the Fédération Régionale de Défense contre les Organismes Nuisibles (FREDON, a farmers’ Thèse C. Morilhat 2005 101
organization for crop protection) surveys the communes and monitors the travelling wave dynamics of A. terrestris populations for outbreak control. Every commune is scored on a yearly basis with the following index: 0, no colony observed; 1, some isolated colonies; 2, colonies present in many pastures and meadows; 3, numerous colonies and serious damage to grassland. Thus, each parcel was also defined according to the phase of the population cycle at scale commune. A TERRESTRIS AND T. EUROPAEA RELATIVE ABUNDANCE ESTIMATION The estimation of A. terrestris and T. europaea relative abundance on the parcel scale was based on an index method described in Giraudoux et al. (1995). Such index methods, calibrated against density estimates based on trapping, are usually employed for large scale studies (Hansson 1979; Delattre et al. 1999; Fichet-Calvet et al. 1999; Giraudoux et al. 1997; Quéré et al. 2000). The surface indices used here, were earth tumulus and occurrence of small mammal holes. A. terrestris presence can reliably be differentiated from T. europaea molehills. Relative abundance of A. terrestris and T. europaea was determined along a line that crossed each parcel’s long diagonal. The diagonal was divided into 10 m intervals and the area observed was 2.5 m on each side of the transect line. Presence or absence of A. terrestris and T. europaea was recorded for each interval. The relative abundance of both species was calculated with the following ratio: “number of positive intervals / total number of intervals” (Duhamel et al. 2000; Quéré et al. 2000; Raoul et al. 2001). The observation of A. terrestris/ T. europaea indices was conducted during periods when vegetation was at its shortest. SURVEY OF A. TERRESTRIS AND T. EUROPAEA POPULATIONS AND FARMING PRACTICES Relative abundance of A. terrestris population was observed during low density, increase and high density phases of a population cycle. Low density phase and increase phase We selected communes that presented populations at low densities (score 0-1) for two years after a high density phase (score 3). In these communes, 46 agricultural parcels (cadastral units) in which A. terrestris and T. europaea were absent in spring 2001 were selected (size: 0.5 – 15 ha) in typical landscapes for the area of study (Delattre et al. 1996). Then, A. Thèse C. Morilhat 2005 102
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N° ordre : 1089 Année 2005 THÈSE
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- au cinéaste Jean-Pierre Riffet,
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4. TROISIÈME PARTIE : influence du
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7.3.4. Relation entre populations d
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MAE : Mesures Agri - Environnementa
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1.1.1. Typologies de dynamique et h
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- les forces ascendantes ou forces
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PHAE) par les Mesures Agri - Enviro
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N 60 km 1995 1994 1993 1990 1991 19
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2002 ). En Franche-Comté, 70% des
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leur colonisation (Delattre et al.,
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des espèces ayant développé des
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1.2.4. Interactions entre campagnol
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MICROTUS ARVALIS Pénétrabilité /
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Campagnol terrestre, taupe et campa
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2. PREMIÈRE PARTIE : suivi des pop
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Jura Figure 7 : Localisation géogr
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i1 i2 i3 10 m i4 5 m Figure 9 : Mé
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3. DEUXIÈME PARTIE : influence des
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parcellaire et la latence communale
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Densités relatives de Talpa europa
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- la somme de T. europaea de 2001 a
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Interactions T. europaea - A. terre
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- une compétition s’instaurerait
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1993) * a été utilisée pour effe
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4.3.2. Influence du contexte paysag
Page 53 and 54: Les corrélations inter variables (
Page 55 and 56: Tableau 5. Corrélations entre les
Page 59 and 60: - nombre de taches de bois et densi
Page 61 and 62: prairie ouverte) sont dominés par
Page 63 and 64: d’un effectif retenu comme statis
Page 65 and 66: 5.2.1.2. Détermination des Fréque
Page 67 and 68: 2 3 1 Figure 18. Carte factorielle
Page 69 and 70: des gradients croissants (Tableau 8
Page 71 and 72: d’étude» (Rodriguez et al., 200
Page 73 and 74: - l’appétence et le groupe taxon
Page 75 and 76: 5.3.2.4. Relation entre populations
Page 77 and 78: Pour cette raison, il a été déci
Page 79 and 80: Influence des Groupes Fonctionnels
Page 81 and 82: Figure 21. Un herbomètre (Fabricat
Page 83 and 84: La relation entre les paramètres s
Page 85 and 86: printemps suivant de M. arvalis ; l
Page 87 and 88: 5.4.2.1.2. Estimation des densités
Page 89 and 90: 5.4.2.2. Résultats 5.4.2.2.1. Eche
Page 91 and 92: Tableau 14. Corrélations entre var
Page 93 and 94: A. terrestris Nos résultats (Table
Page 95 and 96: que dans les parcelles à bordures
Page 97 and 98: micromammifère estimées dans la p
Page 99 and 100: au point de ce jeu de variables a f
Page 101 and 102: Summary 1. Small mammals are the mo
Page 103: shown that farming practices can im
Page 107 and 108: Correlations between population dyn
Page 109 and 110: Influence of soil work on A. terres
Page 111 and 112: wildlife by trampling, thus disturb
Page 113 and 114: cannot thus be considered as an alt
Page 115 and 116: Gilg, O., Hanski, I., & Sittler, B.
Page 117 and 118: Meylan, A. & Höhn, H. (1991) Taupe
Page 119 and 120: Table 1. Description of the 13 farm
Page 121 and 122: Table 3. Correlations between farmi
Page 123 and 124: Squared symbols are sampling parcel
Page 125 and 126: Fig. 2. A. terrestris relative abun
Page 127 and 128: Fig. 4. -3 -2 -1 0 1 2 3 -3 -2 -1 0
Page 129 and 130: 6.3. Relation entre populations de
Page 131 and 132: Les travaux de terrain ont été r
Page 133 and 134: communale) et intègre les DR de T.
Page 135 and 136: Conclusion La précocité du démar
Page 137 and 138: 7.2.2. Analyses pédologiques La va
Page 139 and 140: 7.2.3. Analyse des données Pour ch
Page 141 and 142: limon lf lg proftot (a) vers cn str
Page 143 and 144: Les valeurs du maximum de densité
Page 147 and 148: cinétiques de A. terrestris qu’i
Page 149 and 150: 8. SEPTIÈME PARTIE : SYNTHÈSE et
Page 151 and 152: des dynamiques de populations de A.
Page 153 and 154: Perspectives de recherche Les résu
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T. europaea et M. arvalis Malgré l
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Tableau 18. Corrélations entre les
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Figure 16. Cercle des corrélations
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Bergeron, J.M. & Jodoin, L. (1983)
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Crick, H.Q.P., Baillie, S.R., Balme
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Duchaufour, P. (1995) Pédologie :
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echinococcosis: strategy for eradic
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Hedin, L., Kerguelen, M., & De Mont
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Korpimaki, E., Brown, P.R., Jacob,
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Moissenet, M.F. (1994) Prairies et
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R-Development-Core-Team (2004) R: A
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Taitt, J. & Krebs, C.J. (1985). Pop
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11. ANNEXES Liste des annexes Annex
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DOLE Automne 2003 LONS-LE-SAUNIER C
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ANNEXE 3. Fiches d’identité de A
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Vergers : pommiers, pruniers. Les r
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taupinières caractéristiques. La
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Nom commun : Nom latin : Campagnol
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ANNEXE 4. Contributions absolues de
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ACP « caractéristiques pédologiq
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ANNEXE 6. Commentaires des referees
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The sentence has been modified (pag
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ANNEXE 7. Formulaire mis au point p
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