Remarkable changes of weed species in Spanish cereal fields from 1976 to 2007 Cirujeda, Aibar, Zaragoza To cite this version: Cirujeda, Aibar, Zaragoza. Remarkable changes of weed species in Spanish cereal fields from 1976 to 2007. Agronomy for Sustainable Development, Springer Verlag/EDP Sciences/INRA, 2011, 31 (4), pp.675-688. 10.1007/s13593-011-0030-4. hal-00930501 HAL Id: hal-00930501 https://hal.archives-ouvertes.fr/hal-00930501 Submitted on 1 Jan 2011 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Agronomy Sust. Developm. (2011) 31:675–688 DOI 10.1007/s13593-011-0030-4 RESEARCH ARTICLE Remarkable changes of weed species in Spanish cereal fields from 1976 to 2007 Alicia Cirujeda & Joaquín Aibar & Carlos Zaragoza Accepted: 4 January 2011 /Published online: 18 March 2011 # INRA and Springer Science+Business Media B.V. 2011 Abstract Management practices, geographical gradients Convolvulus arvensis found in more than half of the and climatic factors are factors explaining weed species surveyed fields. L. rigidum was related to dryland, while composition and richness in cereal fields from Northern and the other species were found overall. Furthermore, we Central Europe. In the Mediterranean area, the precise found that management, geographical and climatic factors factors responsible for weed distribution are less known due were significantly related to weed species distribution. In to the lack of data and surveys. The existence of weed particular altitude, survey areas, irrigation and herbicide survey data of year 1976 in the Zaragoza province of the use in post-emergence were the most driving factors Aragón region, Spain, offered us the opportunity to explaining weed species distribution. Species richness compare present weed species with weed species growing was higher in survey areas with extensive management 30 years ago. No detailed comparison of changes in weed practices and increased with altitude excepting a very species composition in cereal fields in that period of time productive area with intensive management practices at has been conducted in the Mediterranean area. Here a high altitude where richness was as low as in the irrigated survey was conducted in the Aragón region from 2005 to lowlands. The main differences found between the 1976 2007. Weeds were surveyed in 138 winter cereal fields in and the 2005–2007 surveys were (1) the striking increase ten survey areas where winter cereals are the main crops, of grass weeds, (2) the high decrease of mean weed using the same methodology applied 30 years ago. In the species number found in each field declining from 9 to 3 Zaragoza province, 36 fields were chosen in the same and (3) the frequency decrease of many weed species municipalities than in the previous survey. Several probably caused by agriculture intensification in that management, geographic and climatic variables of each period of time. The growing importance of other weed fieldwererecordedandrelatedtoweedspecieswith species is probably related to their adaptation to minimum multivariate analysis. Diversity index were calculated and tillage, which is a widespread technique nowadays. relatedtosurveyareaandaltitude. Our results show that out of the 175 species only 26 species were found in Keywords Biodiversity . Canonical correspondence more than 10% of the surveyed fields. The main species analysis . Rare weeds . Weed diversity were Papaver rhoeas, Lolium rigidum, Avena sterilis and : A. Cirujeda (*) C. Zaragoza 1 Introduction Centro de Investigación y Tecnología Agroalimentaria, Gobierno de Aragón, Unidad de Sanidad Vegetal, Patterns of weed species composition in cereal fields are Avda. Montañana 930, 50059 Zaragoza, Spain often attributable to a complex number of interacting e-mail: [email protected] factors and multivariate analysis has been used in many studies to discuss them. Management practices, geographical J. Aibar gradients and climatic factors have been found to be the most Escuela Universitaria Politécnica Superior de Huesca, Ctra. de Zaragoza, Km 67, driving factors to explain weed species composition and 22071 Huesca, Spain richness in Northern Europe (Salonen 1993) and in Central 676 A. Cirujeda, J. Aibar, C. Zaragoza Europe (Pysek et al. 2005; Lososova et al. 2004;Cimalova The most recent weed survey in cereal fields in the and Lososova 2009; Fried et al. 2008). The breadth of the Aragón region was conducted in 1976 describing the flora environmental gradients considered is probably an important of the Zaragoza province (Zaragoza and Maillet 1976; reason explaining discrepancies of the importance of these Zaragoza-Larios and Maillet 1980). The methodology was factors between studies (Fried et al. 2008). So far, no very similar to the one used in our study conducted in multivariate analysis of broad-scale gradients as altitude or 2005–2007 allowing the comparison of the weed flora management practices in cereal fields have been done on 30 years later in the same surveyed area. This way it was weed species composition in Mediterranean areas, but we aimed to provide an insight into any changes that may have hypothesize that both factors may be important in the occurred. Because of lack of data of the rest of Aragón, it is Aragón region due to the broad extent of the altitude not possible to compare the changes in the other two gradient and of the diverse management practices found. provinces. However, extending the survey to these regions Weed species are adapted to crops and to management where a generally more extensive agriculture is common techniques like soil disturbance by tillage or ploughing. can help determine which factors promote diversity of rare However, intensification in the last decades with chemical weed species. To our knowledge, this is the first study that fertilization, use of herbicides, sowing high-competitive establishes a detailed comparison of weed abundance cereal varieties, using seed-cleaning techniques etc. has 30 years ago with nowadays in cereal fields located very reduced species richness (reviewed by Roschewitz et al. close to each other in the same municipalities in the 2005). Studies have been conducted to analyse the Mediterranean region. individual impact of these techniques on weed communities’ The aims of this study were (a) to describe the weed diversity and fertilizationwasfoundtobeanimportant composition in cereal fields of the Aragón region in Spain and factor affecting weed community composition (Pysek and its relationship with climatic, geographic and agronomic Leps 1991). management factors; (b) to find out which are the frequent To assess the real scale of these intensification factors, and the rare weed species and (c) to compare weed species recent surveys have been conducted in many countries to frequency in the same municipalities of the Zaragoza province compare weed flora composition with those of previous 30 years after the survey conducted in 1976. surveys decades ago. Excepting Andreasen and Stryhn (2008) in Denmark, most of the authors describe an important decline in species number (Albrecht 1995, 2 Material and methods Germany; Sutcliffe and Kay 2000, United Kingdom; Lososova et al. 2004 and Pysek et al. 2005, Czech Republic 2.1 Field survey and Slovakia). Detailed comparisons in the Mediterranean area are non-existing but Chamorro et al. (2007) in Spain Aragón is one of the 17 Autonomous Communities of and Speranza et al. (1990) in Italy observed an overall Spain and is located in the north-eastern part of the country. species decline in the last decades based on literature It is comprised of three provinces: Zaragoza, Huesca and comparisons. We hypothesize that weed species number has Teruel between latitude 42.852° N and 39.848° N and also decreased in the most intensive areas of Aragón but longitude 2.159° W and 0.744° E. The Aragón region has may remain high in the extensive areas. diverse landscapes and winter cereal is grown from 160 m Attention on rare species is paid in many of the altitude in the Ebro Basin to 1,400 m in the Pyrenees or in published surveys, which besides their intrinsic value, can the Sistema Ibérico mountains. Agricultural intensification play a role in agroecosystem functioning. These plants serve practices such as seed-cleaning techniques, synthetic as habitat and food for insects, birds and other animals, as well fertilizers and the development of competitive crops are as for soil life. The intense interest shown in some North common throughout, but other techniques such as herbicides European countries for rare arable weeds is less in Spain, and and crop rotations differ considerably within these areas. In the Catalogue of Endangered Species of Flora in Aragón does some highlands of the Teruel and Huesca provinces, not include rare weeds (Gobierno de Aragón 2007). As agriculture is still quite traditional with low-input manage- explained by Braun-Blanquet and de Bolós (1957), the ment and the soil is left set-aside 1 of 2 years. In contrast, in semiarid regions of the occidental Mediterranean area are the irrigated Ebro Basin (Zaragoza province), crop rotations, especially rich in weed species and there is a gradual fertilizers and herbicides are common. To cover the high decrease in weed species number towards the north of diversity of landscape and agricultural practices, the survey Europe. Perhaps intensification in agroecosystems has also was organised by choosing different areas where cereal been lower in Southern Europe than in North European production is important (Fig. 1, Table 1). The number of countries so that we hypothesize to find in our survey more surveyed winter cereal fields was 62, 21 and 55 in 2005, rare species than in other North European countries.