Manuel d'utilisation
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1. Length of habitat a b m 8 0 1 4 5 0 0 8 9 9 1 8 Surface area of habitats a b m2 17 5 4 3 10 3 2 3 19 3 4 5 Distances between the sites occupied by 15 4 6 4 11 6 4 2 13 7 5 7 Lymnaea glabra and L palustris a b m Snail density in each habitat a b 7 5 3 8 6 3 2 3 8 8 45 Total area occupied m2 52 5 31 58 Total area of meadows ha 8 33 2 45 5 25 Percentage of meadow 0 06 0 12 0 11 occupied by snails 178 C VAREILLE MOREL G DREYFUSS D RONDELAUD 6 nature of habitat ponds for Dreyfuss et al open drai nage ditches in our study The differences between densities may be interpreted by hypothesizing that the species richness would be greater in a pond than in an open drainage system From the present study it was found that the habitats of the three species were few in number in the mea dows on acid soil for example a mean of 4 3 per pas ture for L truncatula Their size was restricted and snail densities were low These characteristics must be considered in the control of fasciolosis and one measu re may be proposed As these Lymnaea species act as intermediate hosts for this trematode in the region stu died fencing snail habitats would isolate cattle or sheep from snails and subsequently stop the life cycle of F hepatica as demonstrated by Mage et al 1989 in a farm located in the Correze Department France Subsequent transformation of fenced habitats using2. concerned to habitats on acid soil Bouix Busson amp Rondelaud 1984 reported a mean surface of 10 m2 limits 7 7 22 8 m2 in the Haute Vienne Department Mean densities ranged from 15 9 to 19 8 snails m Rondelaud 1982 and reached 39 snails m in the study by Bouix Busson amp Rondelaud 1984 whereas they ranged from 22 6 to 27 2 snails m2 in our study Our results agree with tho se of these authors The surface area of habitats occupied by L palustris was lower in the report by Dreyfuss et al 1994 than in our study a mean of 10 1 m2 vs 10 3 19 3 m2 Snail density was clearly lower in our observations than in the report of Dreyfuss et al 6 3 8 8 snails m vs 40 7 m2 These differences can be explained by the 5 HABITATS OF LYMNAEA SP ON ACID SOIR 177 Table 1 Characteristics of sites inhabited by Lymnaea truncatula and the total area of the meadows on acid soil a mean value b standard de viation Tableau 1 Caract ristiques des sites colonis s par Lymnaea truncatula et la superficie totale des prairies sur sol acide a moyenne b cart ty pe Parameters Basse Marche Monts d Ambazac Plateaux de la Vienne Number of meadows 15 23 15 Total number of populations 68 90 73 Length of habitat a b m 4 6 1 9 3 0 0 8 5 0 2 1 Surface area of habitats a b m 4 2 12 2 8 0 8 4 8 1 4 Snail density in each habitat a b 19 8 8 5 11 4 6 5 14 4 6 8 Total area occupied m 2
3. en pratique du contr le de I infestation par Fasciola hepatica chez des bovins limousins Bull Group Tech V t n 347 5 10 Moens R 1982 Observations au sujet de la pr dation de Zoni toides nitidus Miiller sur Lymnaea truncatula Miller Buil Ecol 13 273 282 P cheur M 1974 Lutte strat gique contre la distomatose Comptes Rendus de Recherches Travaux du Centre de Re cherches sur les Maladies Parasitaires des Animaux Domestiques n 38 85 150 I R S 1 A Bruxelles Rondelaud D 1975 La pr dation de Lymnaea Galba truncatu la M ller par Zonitoides nitidus M ller moyen de lutte biolo gique Ann Parasitol Hum Comp 50 55 61 Rondelaud D 1977 R sultats et probl mes pos s par l introduc tion de Mollusques Zonitidae dans quelques biotopes Limn es tronqu es en Indre et Haute Vienne Ann Parasitol Hum Comp 52 521 530 Rondelaud D 1981 Le contr le biologique de Lymnaea trunca tula M ller Bilan d une exp rimentation de neuf ann es en Hau te Vienne France Haliotis 11 213 224 Rondelaud D 1982 Le contr le biologique par pr dation de Lymnaea truncatula M ller tude exp rimentale de la dyna mique de cinq esp ces de Mollusques apr s arr t du traitement Malacologia 22 697 700 Rondelaud D 1988 Le contr le mixte et altern de Lymnaea truncatula M ller tude comparative de trois techniques pour l pandage du molluscicide Ann Re
4. only a tiny proportion of the overall meadow area The mean intervals between the sites occupied by L truncatula and L glabra ranged from 6 3 m in Monts d Ambazac to 12 3 m in Basse Marche with a si gnificant difference between Monts d Ambazac and each of the two other districts Intervals between L glabra and L palustris were higher 11 6 to 15 4 m but with no significant differences between districts In June the snail ranged from 11 4 to 19 9 m for L truncatula from 22 6 to 27 2 m2 for L glabra and from 6 3 to 8 8 m for L palustris No significant dif ferences in the mean densities of each species between the three districts were noted The comparison of mean densities of each species was also made in relation wi th the nature of substratum and the altitude There we re no significant differences 5 Discussion In the L truncatula habitats located on sedimentary soils the snail lived in widespread habitats For example the surface of colonized sites was 22 ha in the region of Gembloux Belgium Van den Bruel 1968 whereas the four studied farms stretched over 103 ha in which L truncatula was present in 21 of mea dows The high values were also present in the work by P cheur 1974 the surface of snail habitats was 1 to 4 ha and snails colonized 5 to 40 of the mea dow surface in the three farms studied in Belgium Moens 1982 and Rondelaud 1988 gave clearly lo wer surfaces for habitat
5. the emersed zones of each area as well as in stagnant or shallow waters no more than 5 cm in depth during the study period The snail sear ch in each habitat and subsequent count were first ma de by one person over 15 to 20 min A control in each habitat was subsequently performed over 10 to 15 min by a second person to collect any snails that had esca ped the first investigator All searches and counts were made before the summer growth of hygrophilous plants which occurred in mid July Lastly the calcula tion of snail density was performed for each Lymnaea species and each habitat by dividing the total number of snails collected by the corresponding surface area Mean values and standard deviations were calcula ted from the individual meadow values for each para meter taking into account the geographical district and snail species These values were then analyzed by one way analysis of variance Stat Itcf 1988 4 Results The figure 1 represents the location of habitats for each Lymnaea species along the drainage network L truncatula inhabited the extremity of the 231 furrows and the surrounding areas The two other species are less frequent L glabra was found only in the middle part of 127 furrows out of 231 and L palustris in the 176 C VAREILLE MOREL G DREYFUSS D RONDELAUD 4 most downstream part of 9 central ditches and some times in the lower part of the first furrows The mean values and standard de
6. when the snails are exposed to miracidia only in the days following their hatching Kendall 1950 Busson et al 1982 Various methods to control these interme diate hosts have been proposed including agronomic 174 C VAREILLE MOREL G DREYFUSS D RONDELAUD 2 techniques drainage the use of molluscicides revie wed by Taylor 1965 and Euzeby 1971 or the intro duction of carnivorous snails in lymnaeid habitats Rondelaud 1975 1981 However except for draina ge these methods have seldom been used in L trunca tula habitats in French meadows L truncatula is frequent in swampy meadows on acid soil In the Haute Vienne Department central France snail habitats are confined to the peripheral extremities of open drainage furrows and ditches Ho wever two other lymnaeid species L glabra L pa lustris live in other isolated habitats in the lower levels of the same drainage networks Bouix Busson amp Ron delaud 1984 Vareille et al 1996 Colonies of each Lymnaea species were found to be isolated from those of other species with no overlap In view of these fin dings the question arose as to whether fasciolosis control might be affected by isolating Lymnaea habi tats from other parts of the meadow and subsequently from cattle Preliminary studies on the characteristics of the habitats of each species would be necessary to determine conditions in which this management tech nique could be used The present paper gi
7. 86 252 350 Total area of meadows ha 36 5 28 7 20 2 Percentage of meadow 0 08 0 09 0 17 occupied by snails Table 2 Characteristics of sites inhabited by Lymnaea glabra and the total area of the meadows on acid soil a mean value b standard devia tion Tableau 2 Caract ristiques des sites colonis s par Lymnaea glabra et la superficie totale des prairies sur sol acide a moyenne b cart type Parameters Basse Marche Monts d Ambazac Plateaux de la Vienne Number of meadows 15 23 15 Total number of populations 68 90 43 Length of habitat a b m 14 3 6 2 7 2 2 3 12 2 4 2 Surface area of habitats a b m2 7 2 14 3 6 0 8 59 1 1 Distances between the sites occupied by 12 3 5 2 6 3 2 6 10 7 4 3 Lymnaea truncatula and L glabra a b m Snail density in each habitat a b 26 0 10 7 22 6 8 4 27 0 9 5 Total area occupied m2 274 180 232 Total area of meadows ha 36 5 28 7 20 2 Percentage of meadow 0 07 0 06 0 11 occupied by snails Table 3 Characteristics of sites inhabited by Lymnaea palustris and the total area of the meadows on acid soil a mean value b standard de viation Tableau 2 Caract ristiques des sites colonis s par Lymnaea palustris et la superficie totale des prairies sur sol acide a moyenne b cart type Parameters Basse Marche Monts d Ambazac Plateaux de la Vienne Number of meadows 3 3 3 Total number of populations 3 3 3
8. Annls Limnol 35 3 1999 173 178 The characteristics of habitats colonized by three species of Lymnaea Mollusca in swampy meadows on acid soil their interest for control of fasciolosis C Vareille Morel G Dreyfuss2 D Rondelaud3 Keywords acid soil fasciolosis habitats Lymnaea swampy meadow Malacological investigations were carried out in 53 meadows on acid soil to identify the characteristics of habitats colonized by lymnaeid snails These meadows are located in three different geographical districts Basse Marche Monts d Ambazac Pla teaux de la Vienne in the Haute Vienne Department central France Lymnaea truncatula lived at the distal extremity of open drainage furrows L glabra inhabited the middle part of furrows and L palustris lived in the central ditch The mean area of L truncatula habitats ranged from 2 8 to 4 8 m2 in relation to the district studied and was smaller than those of L glabra a mean of 3 6 to 7 2 m and L palustris 10 3 to 19 3 m2 Mean intervals between the sites occupied by L truncatula and L glabra ranged from 6 3 to 12 3 m they were greater between the sites occupied by L glabra and L palustris 11 6 to 15 4 m Finally the mean densities of L truncatula in June ranged from 11 4 to 19 8 m2 in relation to the district studied those of L glabra ran ged from 22 6 to 27 0 snails m whereas in L palustris they ranged from 6 3 to 8 8 snails m The mean values of these first two par
9. agronomic methods would eliminate snails by sup pressing moisture excess Extension of these measure to other regions or countries of western Europe loca ted on acid soil might serve to eradicate fasciolosis from local cattle and sheep References Bouix Busson D amp Rondelaud D 1984 Etude de relations entre deux esp ces de limn es dans leurs habitats naturels Rev M d V t 135 449 457 Busson P Busson D Rondelaud D amp Pestre Alexandre M 1982 Donn es exp rimentales sur l infestation des jeunes de cinq esp ces de limn es par Fasciola hepatica Ann Parasitol Hum Comp 57 555 563 Dreyfuss G Moukrim A Rondelaud D amp Vareille Morel C 1994 Several field observations concerning infection of Lym nae palustris by Fasciola hepatica J Helminthol 68 115 118 Euzeby J 1971 Les maladies vermineuses des animaux domes tiques et leurs incidences sur la pathologie humaine Tome II Section 2 Book 1 Vigot Fr res Paris 798 p Guy F Rondejaud D Botineau M Dreyfuss G amp Ghestem A 1996 Etude de relations entre les plantes les plus fr quentes et l abondance de Lymnaea truncatula M ller vecteur de Fasciola hepatica Linn dans les prairies mar cageuses sur sol acide Rev M d V t 147 465 570 Kendall S B 1950 Snail hosts of Fasciola hepatica in Britain J Helminthol 24 63 74 Mage C Reynal P Rondelaud D amp Chasteloux C 1989 Mise
10. ameters were significantly lower in the habitats located in Monts d Ambazac than those recorded in the two other districts Im plications of these results for fasciolosis control are discussed Les caract ristiques des habitats colonis s par trois esp ces de Lymnaea Mollusques dans les prairies mar cageuses sur sol acide leur int r t pour le contr le de la fasciolose Mots cl s mollusques Lymnaea fasciolose habitats Haute Vienne prairie mar cageuse sol acide Des investigations malacologiques ont t r alis es dans 53 prairies afin de d terminer les caract ristiques des habitats coloni s s par des mollusques Lymnaeidae Ces prairies sont localis es dans trois secteurs g ographiques diff rents du d partement de la Haute Vienne Basse Marche Monts d Ambazac Plateaux de la Vienne Lymnaea truncatula vit l extr mit distale des ri goles de drainage superficiel L glabra colonise la partie moyenne des m mes rigoles et L palustris vit dans le foss central La superficie moyenne des habitats de L truncatula varie de 2 8 4 8 m selon le secteur tudi et est plus petite que celles relev es dans les g tes de L glabra 3 6 7 2 m2 ou de L palustris 10 3 19 3m2 Les distances moyennes entre les sites occup s par L truncatula et L glabra fluctuent entre 6 3 et 12 3 m elles sont plus grandes entre les zones coloni es par L glabra et L pa lustris 11 6 15 4 m Enfin les densit s moy
11. ch V t 19 279 282 Smith G amp Wilson R A 1980 Seasonal variations in the micro climate of Lymnaea truncatula habitats J Appl Ecol 17 329 342 Stat Itcf 1988 Manuel d utilisation Institut Technique des C r ales et des Fourrages Service des tudes Statistiques Boigne ville 210 p Taylor E L 1965 Fascioliasis and the liver fluke F A O eri cultural Studies Roma n 64 235 p Van den Bruel W E 1968 Rapport d activit 1968 Groupe de travail pour tude de la lutte contre les limn es Station de Zoo logie Appliqu e de l tat Centre de Recherches Agronomiques Gembloux Belgium 62 p Vareille L Vareille Morel C Dreyfuss G amp Rondelaud D 1996 Les g tes limn es dans les prairies mar cageuses sur sol acide les effets d impacts agricoles Annls Limnol 32 97 104 Vilks A 1991 Analyse chorologique de la flore vasculaire du Li mousin Th se de Doctorat Universit de Limoges n 36 247 p
12. ennes de L truncatula en juin varient de 11 4 19 8 m2 selon le secteur d tude celles de L glabra fluctuent entre 22 6 et 27 0 mollusques m alors que chez L palustris elles se situent entre 6 3 et 8 8 mol lusques m2 Les moyennes des deux premiers param tres sont significativement plus faibles dans les g tes situ s dans les Monts d Ambazac que celles enregistr es dans les deux autres secteurs Les implications de ces r sultats dans le contr le de la fascio lose sont discut es act as intermediate hosts in the life cycle of the liver fluke Fasciole hepatica Linnaeus In France the main snail host in Lymnaea truncatula O F M ller which may be infected at any age Other Lymnaea spe cies such as L glabra O F M ller or L palustris O F M ller are also present in pastures and may as 1 Introduction Prevention of fasciolosis in cattle involves a number of measures One measure is control of the snails that 1 Facult des Sciences Laboratoire de Malacologie Appliqu e 123 avenue Albert Thomas F 87060 Limoges Cedex 2 Facult de Pharmacie Laboratoire de Parasitologie 2 rue du Docteur Raymond Marcland F 87025 Limoges Cedex 3 Facult de M decine Laboratoire d Histopathologie Parasitaire 2 rue du Docteur Raymond Marcland F 87025 Limoges Cedex Article available at http Awww limnology journal org or http dx doi org 10 1051 limn 1999024 sure the complete larval development of F hepatica
13. o a brook From this central ditch smaller furrows lead off draining water from the meadow Fig 1 The length of the central ditch ranges from 95 to 135 m their width 50 75 cm and their dep th 20 25 cm The length of furrows is varying from 30 to 80 m in Monts d Ambazac meadows and from 60 to 100 m in the meadows of the other two districts Their width and depth are 40 45 cm and 12 15 cm res pectively The climate is essentially continental but under so me oceanic influence with wet weather coming from the west Average annual rainfall ranged from 800 to 1 100 mm depending on altitude Average annual tem perature was 10 to 10 5 C with a decrease of 0 55 C for each increasing 100 m Vilks 1991 Hygrophilous vegetation in the Basse Marche mea dows belongs to the Junco Cynosuretum cristati asso ciation although Cynosurus cristatus is rare In the Monts d Ambazac meadows the vegetation belongs to the Caro verticillati Juncetum acutiflori association The plant community of the Plateaux de la Vienne meadows belongs also to the Caro verticillati Junce tum acutiflori association but Carum verticillatum is absent A total of 43 meadows were grazed by cattle over the year of the study and the 10 others by sheep Hygrophilous vegetation was mowed in August or September and the drainage furrows and ditches were cleared in October November 3 Methods Two campaigns 1994 1995 were carried out to stu dy the habita
14. s on sedimentary soil with 99 6 m2 per habitat for the former author and 42 5 m2 for the latter In contrast the results given by Ronde laud 1977 in the department of Haute Vienne were closer to the values we obtained In 23 habitats coloni zed by L truncatula this author reported a mean sur face of 9 1 m2 A comparison of these data demonstra ted that L truncatula habitats had a limited surface in opposite to that recorded in snail habitats located in se dimentary soil regions The density of L truncatula in its habitats was also dependent on the nature of the subsoil In habitats lo cated in sedimentary soil most snail densities in June July ranged from 20 to 101 L truncatula m Van den Bruel 1968 P cheur 1974 Smith amp Wilson 1980 Moens 1982 In acid soil habitats snail densities were clearly lower with a mean value of 25 6 snails m in the work by Rondelaud 1977 and mean densities from 11 4 to 19 8 m2 in the present study From this comparison it can be assumed that habitats on acid soil were less populated than those on sedimentary soil The presence of the terrestrial carnivorous snail Zonitoides nitidus O F Miiller in the hygrophilous zones of acid soil meadows Rondelaud 1975 may gi ve an explanation for Z nitidus ate numerous emersed L truncatula in July and therefore limited the size of L truncatula populations Little information concerning the habitats of L gla bra is available and only
15. ts of Lymnaea species in June July becau se of the highest snail densities during these two months The distributions of the three lymnaeid spe cies were first identified in 1994 by following the open drainage systems from the terminal extremity of each furrow until the mouth of the drainage ditch in the brook Investigations were subsequently performed in 1995 to determine i the length of furrow or ditch in habited by each species ii the surface area of each snail location including places trampled by cattle 111 the distance between populations of different species in the same drainage system and iv the snail density per m of habitat in June The total surface area of eve ry 53 meadows was also calculated to determine the percentage of the surface area occupied by each spe cies The values of the parameters i 11 and iii were first measured in each meadow before snail count Snails 3 HABITATS OF LYMNAEA SP ON ACID SOIR 175 Habitats of L truncatula Habitats of L glabra Habitats of L palustris Drainage ditch Drainage furrow Fig 1 Generalized location of the habitats of the three ene species in the open drainage systemps of meadows on acid soil in the Haute Vienne Department France Fig 1 Localisation g n rale des habitats des trois esp ces de limn es sur les r seaux de drainage superficiel dans les prairies sur sol acide dans le d partement de la Haute Vienne were then collected in
16. ves the re sults of a quantitative study of 53 acid soil meadows in the Haute Vienne Department each with an open drai nage network 2 Stations studied The 53 studied meadows were distributed among three geographical districts In Basse Marche 15 hy gro mesophilous meadows were located within a 7 km radius around the town of Bellac Altitude 190 268 m In the Monts d Ambazac district there were 23 meadows in the communes of Compreignac Nan tiat and Thouron Altitude 300 420 m The third dis trict Plateaux de la Vienne included 15 meadows wi thin a 10 km radius of the Limoges city Altitude 274 370 m The subsoil comprises crystalline or metamorphic rocks Twenty meadows in Monts d Ambazac have un derlying two mica granite The substratum of the others is more variable although migmatites underlaid 20 meadows All soils are hydromorphous Water is running in the furrows from mid October to the end of June or the beginning of July with summer drying of habitats from mid June to the end of August Water is oligocalcic with a calcium ion content ranging from 3 to 26 8 mg l and a pH from 5 5 to 7 8 Guy et al 1996 The habitats of L truncatula and L glabra contained few or no mud but mud is more frequent in the L palustris habitats and usually constitutes a layer from 1 to 3 cm Most meadows are in valleys and have open draina ge systems Typically a central drainage ditch runs from a spring emptying int
17. viations of parame ters recorded in the sites occupied by L truncatula L glabra and L palustris are given in the tables 1 2 and 3 respectively The mean length of the furrow inhabited by L trun catula populations ranged from 3 0 to 5 0 m The mean values were higher for the other two species from 7 2 to 14 3 m for L glabra 5 0 to 9 9 m for L palustris For each species the length of habitats was signifi cantly shorter in the Monts d Ambazac district than in the two others L truncatula Fy 99g 4 59 P lt 0 05 L glabra Fy 124 6 37 P lt 0 01 L palustris Fy 6 17 50 P lt 0 01 In the opposite there was no signifi cant difference between the values of Basse Marche and Plateaux de la Vienne whatever the lymnaeid spe cies The surface areas of habitats inhabited by L trunca tula 2 8 to 4 8 m2 and by L glabra 3 6 to 7 2 m2 were clearly lower than for L palustris 10 3 to 19 3 m2 per habitat For each species the areas were signifi cantly lower in Monts d Ambazac district than in the other two geographical zones L truncatula F 338 6 37 P lt 0 01 L glabra Fy 424 33 40 P lt 0 001 L palustris Fy 6 60 54 P lt 0 001 This occupied area did not differ significantly in Basse Marche and in Plateaux de la Vienne for L truncatula or L palustris but did so for L glabra F 154 6 79 P lt 0 01 The total area occupied by lymnaeid snails regardless of species was
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