Fundam. appl. Nemalol., 1995, 18 (6), 567-574 The occurrence and distribution of Xiphinema species (Nematoda : Dorylaimida) in Spanish fir woodlands Domingo JIMÉNEZ GUlRADO, Maria Dolores G. GUTIÉRREZ, Javier c. ALHAMA and Susana C. ARcos Depa-rtamento de Biologia Animal, Facultad de Ciencias, San Alberto iVIagno sin, Universidad de C6rdoba, 14004 C6rdoba, Spain. Accepted for publication 9 November 1994. Summary -A comparative study was made to investigate the influence of sorne edaphic factors on the occurrence and relative abundance of four Xiphinema species found in the soils of tive selected tir forests (Abies pinsapo Boiss.) in southern Spain. The samples were taken seasonally for one year. Univariate (one-way analysis of the variance) and multivariate (cluster and correspond­ ence analyses) methods were applied in order to relate species tO habitat characteristics and to reveal their distribution patterns throughout the studied areas. Three of the species seem to be distributed in accordance with the texturaI gradient of the soils. X. sphaerocephalum Lamberti, Castillo, G6mez-Barcina & Agostinelli, 1992 showed the largest frequency of occurrence and relative abundance in soils on calcareous rocks, but was not found on peridotites, i.e. more sandy soils. It prefered the most silty textures. X. pruhLaicum (Tulaganov, 1938) Kirjanova, 1951 was found in clayey texnued soil more clearly sub;ected to Mediterranean climatic conditions. X. diversicaudalUm (Micoletzky, 1927) Thome, 1939 gave evidence of a strong relationship with more sandy textured, acid soils with high silt content. Finally, X. lUrcicum Luc & Dalmasso, 1964 was rarely found and at such very low numbers that its distribution becomes obscure in these soils. Résumé - Présence et répartition d'espèces de Xiphinema (Nematoda : Dorylaimida) dans des forêts de sapin, en Espagne - Une étude comparative a été réalisée en vue de définir l'influence des facteurs édaphiques sur la présence et l'abondance relative de quatre espèces de Xiphinema observées dans le sol de cinq forêts de sapin (Abies pinsapo Boiss) du sud de l'Espagne. Les prélèvements ont été effectués de façon saisonnière pendant une année. Afin de relier la présence des espèces avec les caractéris­ tiques de l'habitat et mettre en évidence leur mode de répartition dans les aires étudiées, les méthodes d'analyses univariées (analyse linéaire de la variance) et multivariées (analyses en grappe et de correspondance) ont été utilisées. La répartition de trois des espèces s'est révélée correspondre aux gradients de texture du sol. X. sphaerocephalum montre ses plus grandes fréquence et abondance relative dans les sols à roche-mère calcaire, mais n'a pas été trouvé sur les péridotites, c'est-à-dire dans des sols plus sableux, préférant les texnues plutôt limoneuses. X. pruhLaicum est rencontré dans les sols à texture argileuse plus nettement soumis aux conditions climatiques méditerranéennes. La répartition de X. diversicaudaLUm est très nettement liée aux sols acides de texture plus sableuse avec un taux élevé d'argile fine. X. lUrcicum, enfin, n'est rencontré que très rarement et en faible nombre, aussi sa répartition dans ces sols demeure-t-elle obscure. Key-words : ecology, distribution, edaphic factors, Xiphinema, Spanish tir forests. Spanish fir forests are relict zones with Abies pinsapo X. sphaerocephalum tends to show the largest frequen­ Boiss. as the characteristic or prevalent tree species, 10­ cy ofoccurrence and population size and its distribution cated in restricted mountainous parts of the southern pattern in the area can be more clearly defined; this area of the Iberian Peninsula, the Betic and Subbetic provides initial information on the ecology of this spe­ Mountains, with altitudes often over 1000 m. These cies. No previous ecological and/or distribution data are woodlands are related with other Abies woods from known from the literature and it has been recorded only northern Africa. During auturnn-summer of 1992-93 twice, both on the Iberian Peninsula, by Larnberti el al. soil samples were collected around fir trees from isolated (1992) and by Roca and Bravo (1993). However, sorne areas. The study of the nematofauna showed the pres­ data has been reported for the other species studied. ence of the foliowing four species of Xiphinema Cobb, Cohn (1969) relates X. pachlaicum (cited as X. mediter­ 1913 : X. sphaerocephalum Lamberti, Castillo, G6mez­ raneum Martelli & Larnberti, 1967) to loarny and clayey Barcina & Agostinelli, 1992; X. pachlaicum (Tulaganov, heavy soils and X. diversicaudatum to sandy lighter soils 1938) Kirjanova, 1951; X. diversicaudalum (Micolet­ in Israel. Dalrnasso (1970), frorn a study of the family zky, 1927) Thorne, 1939 and X. LUrcicum Luc & Dal­ Longidoridae in France, concludes that X. pachlaicum is masso, 1964. a species present in alluvial and other non-sandy soils, fSSN 1164-5571/95/06 S 4.00/ © Gawhier-Villars - ORSTOM 567 D. Jimenez Guirado et al. Table 1. Seasonal values of pH, organic malter % (Q.M.), nilrogen % (N), C: N ratio, sand % (SA), silt % (SI) and clay % (CL), and Zone/Site pH a.M. N w u w u w u Ronda 1 7.68 7.23 7.14 7.38 28.00 9.35 11.98 8.48 0.63 0.26 0.30 0.23 2 7.38 7.12 7.28 7.22 24.83 12.02 17.66 13.56 0.72 0.37 0.51 0.38 3 7.72 7.38 7.20 7.44 44.09 20.19 23.74 30.14 0.57 0.69 0.70 0.73 4 7.80 7.21 7.24 7.35 14.88 9.48 5.88 8.45 0.43 0.37 0.26 0.29 its 7.36 t 0.20 17.67± 9.96 0.47± 0.18 Parauta 5 6.86 6.54 6.28 6.41 53.39 17.35 3.74 10.17 1.43 0.62 0.09 0.30 6 7.40 7.11 6.55 6.99 9.30 3.66 16.54 15.47 0.29 0.10 0.36 0.51 7 7.32 6.98 6.78 7.05 18.51 8.75 16.26 10.18 0.48 0.23 0.46 028 8 7.54 7.05 6.96 7.18 5.45 4.98 5.54 7.49 0.17 0.18 0.15 0.26 i±s 6.94 ±0.34 12.92± 11.56 0.37± 0.31 Yunquera 9 6.90 6.86 7.10 7.02 18.32 2.62 12.04 8.56 0.47 0.12 0.36 0.30 10 7.14 6.92 7.12 7.02 9.02 7.38 5.00 6.15 0.20 0.24 0.19 0.19 Il 7.31 6.88 7.04 7.17 4.15 6.67 7.64 7.60 0.12 0.27 0.19 0.24 i±s 7.04tO.13 7.93± 3.90 0.24 ±0.10 Genalguacil-Estepona 12 6.65 6.49 6.37 6.28 10.60 6.59 7.74 8.34 0.22 0.17 0.18 0.23 13 6.44 6.23 6.30 6.45 10.90 7.78 8.86 8.98 0.33 0.29 0.29 0.37 14 6.39 6.17 5.86 6.22 8.37 5.49 7.84 6.46 0.24 0.16 0.26 0.19 i±s 6.32± 0.19 8.16± 1.52 0.24± 0.06 Grazalema 15 7.52 7.40 6.91 7.08 21.81 9.78 7.56 18.33 0.56 0.36 0.23 0.49 16 7.79 7.48 7.53 7.56 14.55 12.15 16.18 9.47 0.32 0.27 0.23 0.19 17 7.70 7.21 7.34 7.45 17.39 15.56 14.30 12.14 0.55 0.69 0.53 0.48 18 7.48 7.35 7.01 7.26 18.18 12.38 9.40 10.74 0.42 0.30 0.24 0.28 i±s 7.38 ±0.23 13.75 ±3.84 0.38±0.15 with relatively high silt content, and weil adapted to sand and organic matter content; Navas el al. (1988) Mediterranean climatic conditions, while X. diversicau­ concluded that this species may occur in practically ail dalum is found mainly in wetter soils in an Atlantic mountainous peninsular zones with siliceous soils as climate. According to Arias el al. (1985), X. pachtaicum weil as in sorne Atlantic areas. Its ecological behaviour is is a species frequent in Spain; it is associated with arable the opposite of that in X. pachtaicum. Finally, informa­ lands (soils deficient in organic matter) and tolerates dry tion on X. lurcicum is scarce. It was recorded by Arias el conditions (see Arias el al., 1986 for Central Region). al. (1985) in different localities, by Pefla Santiago and Navas el al. (1988) did more extensive studies, which Jiménez Millan (1986) in eastern Andalusia (mainly as­ documented the potential distribution of this species in sociated with sclerophyllous forests) and included by Mediterranean areas of the Iberian Peninsula with calca­ Bello el al. (1986) in the southwest central group in a reous or siliceous soils, as weil as broad zones in the general biogeographical classification of sorne plant­ northern and southern Plateau with calcareous and parasitic species in Spain. clayey soils. A similar analysis was carried out by these Univariate and multivariate statistical analyses pro­ authors for X. diversicaudalum, which appears to be as­ vide a more objective tool for exploring patterns relating sociated with natural or uncultivated soils with a high species ta their habitats and may be used ta reveal trends 568 Fundam.