Diversitat de papallones diürnes a Andorra

(ENG) A series of characteristics common to butterflies have made these an important group of bioindicator organisms. Many species have strict ecological requirements, which make them particularly sensitive to environmental changes. They also are active during the day, are fairly conspicuous and, generally, easy to identify. They are, therefore, a particularly advantageous group to study as they can provide interesting information when diagnosing the state of the ecosystems and when valuating the most appropriate measures for their conservation. With this premise, the «Butterfly Monitoring Scheme» (BMS) (Pollard & Yates, 1993) was created in the United Kingdom, which has since been adopted by other countries, and particularly in Catalonia. The BMS in Catalonia (CBMS) (Stefanescu, 2000), was set up in 1994 and has generated an enormous volume of information, which, as the years go by, and the seasonal data collected increases, becomes increasingly relevant. The BMS standardised methodology is based on linear transects. Once a week, a visual count of the butterflies found on a previously defined route is carried out. The routes are divided into sections which correspond to the different habitats they cover, and have an average length of 2kms. The counts are done in the morning, so long as the minimum meteorological requirements are met, from the first week in March to the last week in September (30 weeks a year) and the time taken to cover the route is between one and three hours. The observer walks at a constant speed throughout the route and notes down on specific field sheets all the butterflies observed in each section, within a margin of 2.5m on either side of the path and up to 5m ahead of the observer. The BMS sampling methods provide very precise data on the abundance of butterfly populations, on the changes over time of these populations on a local or regional level and on the factors that cause these changes. BMS basically provides very valuable information on the conservation of ecosystems and, indirectly, on the lepidoptera fauna found there. At the moment, the use of the CBMS data is answering questions as diverse as, for example, the migrations of some species (Stefanescu, 1997, 2001), the effects of the climatic changes (Stefanescu et al., 2003), the factors which condition the butterfly diversity in the Mediterranean areas (Stefanescu et al., in press), or the population dynamics (Stefanescu & Planas, 2003). The foreseeable introduction of this methodology in Andorra is highly desirable. Together with the rest of the CBMS network, it would provide data on the Pyrenean lepidopterae, particularly those found above 1600m, as these environments are insufficiently represented in the routes functioning at present. On a local scale, it would fill a significant gap in the understanding of the butterflies in Andorra, particularly on their habitat preferences and their population dynamics. With an accurate species census a precise map of the distribution of these species can be drawn up and precise ecological and biological data collected which will enable a valuation of the true state of the butterflies in Andorra and the consequent action necessary for their conservation to be taken.