ZOBODAT - www.zobodat.at Zoologisch-Botanische Datenbank/Zoological-Botanical Database Digitale Literatur/Digital Literature Zeitschrift/Journal: Libellula Jahr/Year: 2010 Band/Volume: 29 Autor(en)/Author(s): Knijf Geert De, Demolder Heidi Artikel/Article: Odonata records from Alentejo and Algarve, southern Portugal 61-90 ©Ges. deutschspr. Odonatologen e.V.; download www.libellula.org/libellula/ und www.zobodat.at Odonata records from Alentejo and Algarve 15. August 201061 Odonata records from Alentejo and Algarve, southern Portugal Geert De Knijf and Heidi Demolder Research Institute of Nature and Forest (INBO), Kliniekstraat 25, B-1070 Brussels <[email protected]>, <[email protected]> Abstract During two field trips in summer 2008 and spring 2009 to the Alentejo and Algarve in southern Portugal, we altogether recorded 42 species of Odonata at 112 localities. All localities were classified in one of the following five categories: streams, rivers, ponds and pools, reservoir lakes, and brackish waters. Seventeen species are categorised as rheophilous and twelve as having a clear preference for standing waters. Remarkable records of Lestes dryas, Onychogomphus forcipatus, O. uncatus, Paragomphus genei, Or- thetrum chrysostigma, O. coerulescens, O. nitidinerve, O. trinacria, Diplacodes lefebvrii, Brachythemis impartita and Zygonyx torridus are presented in detail and discussed, and a regional distribution map is provided for most of them. With 35 species, the Odonata fauna of southern Portuguese streams and rivers is rich and diverse. This diversity can be explained by the high naturalness of many fluvial systems, resulting in a high degree of variation in velocity and substrate, and by the regionally warm climate. Nearly all endemic and threatened species are restricted in the region to running waters. This demonstrates very well the great importance of streams and rivers for dragonflies and the international responsibility of Portugal to protect and conserve these habitats. Despite their rarity in southern Portugal, ponds and pools harbour relict populations of several northern species like Lestes dryas and Libellula quadrimaculata at the limits of their distribution. However, today these ponds are endangered by intensification of agriculture and the loss of tradi- tional land use practices and should also be protected. Zusammenfassung Libellennachweise aus dem Alentejo und der Algarve, Südportugal (Odonata) — Im Rahmen zweier Exkursio nen in die Regionen Alentejo und Algarve im Süden Portugals im Sommer 2008 und im Frühjahr 2009 wiesen wir an insgesamt 112 Fundorten 42 Libellenarten nach. Alle Lo- kalitäten wurden jeweils einer der folgenden Kategorien zugeordnet: Bach, Fluss, Teich und Becken, Stausee und Brackwasser. Siebzehn Arten wurden demnach als rheophil klassi- fiziert und zwölf Arten hatten eine eindeutige Vorliebe für Stillgewässer. Es werden be- merkenswerte Nachweise von Lestes dryas, Onychogomphus forcipatus, O. uncatus, Pa- ragomphus genei, Orthetrum chrysostigma, O. coerulescens, O. nitidinerve, O. trinacria, Libellula 29 (1/2) 2010: 61-90 ©Ges. deutschspr. Odonatologen e.V.; download www.libellula.org/libellula/ und www.zobodat.at 62 Geert De Knijf & Heidi Demolder Diplacodes lefebvrii, Brachythemis impartita und Zygonyx torridus im Detail präsentiert und diskutiert. Für die Mehrzahl dieser Arten wurden zudem regionale Verbreitungskarten erstellt. Die Libellenfauna südportugiesischer Bäche und Flüsse ist mit 35 Arten als reich und mannigfaltig zu werten. Diese hohe Vielfalt kann mit der großen Naturnähe vieler Gewässersysteme erklärt werden, die zu einer starken Variabilität bei der Fließgeschwin- digkeit und im Substratangebot führt; dazu kommt noch das warme Klima der Region. Fast alle endemischen und gefährdeten Arten sind in Portugal in ihrem Lebensraum auf Fließgewässer beschränkt. Dies belegt sehr gut die hohe Bedeutung von Bächen und Flüs- sen für Libellen und die internationale Verantwortung des Landes für den Schutz und die Erhaltung dieser Habitate. Teiche und Becken stellen trotz ihrer Seltenheit in Südportugal essentielle Lebensräume für Reliktpopulationen nördlicher Arten wie Lestes dryas und Libellula quadrimaculata an den Grenzen ihrer Verbreitung dar. Derartige Kleingewässer sind heutzutage jedoch von der Intensivierung der Landwirtschaft und der Aufgabe tradi- tioneller Bewirtschaftungsweisen bedroht und sollten ebenfalls geschützt werden. Introduction The Mediterranean basin does not only harbour rare and threatened habitats, many species are also restricted to this region. As a consequence, the Mediter- ranean has been recognised as a global biodiversity hotspot with a high level of endemism ( 1999; et al. 2000). Portugal is the most southwestern country of the European continent. Although Blondel & Arronson Myers ( et al. 2009; et al. 2009), it hosts not only a number of western Europeanthe country and does all Ibero-Maghrebiannot support the richest endemics dragonfly ( fauna et of al. the 2006), Mediterranean but also a goodBoudot number of EthiopianRiservato species. Until very recently the odonate fauna of Por- tugal received little attention, despite its distinctFerreira and diverse fauna. It was only published ( 2005), followed in 2006 by a revised checklist ofin the2005 Odonata that a firstfauna bibliography of Portugal ( of the odonatological et al. 2006). literatureA national of survey Portugal or map was- Ferreira & Weihrauch - al surveys have been carried out inFerreira the Peneda-Gerês National Park ( et al.ping 2005), of dragonflies the Natural in thePark entire of Serra country do Alvão is just ( starting up. et al.At 2008)the moment and the region Serra da Estrela National Park ( et al. 2009), all situated in northernFerreira Portugal. The southern part of Portugal has a distinctMoreira climate, much warmer and drier than the rest of the country.Ferreira As a consequence, several species with an African origin – e.g. Brachythemis impartita, Trithemis annulata, Paragomphus genei and Anax ephippiger 1983, 1985; 2005a). However thorough odonatological surveys in both southern –regions have been are scarce.found inThe the most Alentejo substantial and the regional Algarve contributions (e.g. Aguiar have& Aguiar been made by Lohr (2005a), who investigated 35 localities for their drag- (2008) with 43 sites. Furthermore, (1997) published anLohr Odonata atlas for the western Algarve. et al. (2008) onfly fauna, and by Malkmus & Ruf Gardiner Fulan Libellulainvestigated 29 (1/2) 105 2010: sites 61-90 in a very small area in eastern Alentejo. Apart from these, ©Ges. deutschspr. Odonatologen e.V.; download www.libellula.org/libellula/ und www.zobodat.at Odonata records from Alentejo and Algarve 63 several contributions have been published on the local fauna or on spring and autumn phenology of Odonata ( 1996; 1996; 1996; - 1996, 1998; 1996; 2003). Nearly all of these works have been published by foreignHartung authors andJahn are basedJones on observationsMalk duringmus their holidayRöhn trips. Weihrauch & Weihrauch is different, an expanded region, generally of low rolling hills, with comparatively littleThe tourism. Algarve isIt Portugal’sis divided mostinto foursouthern districts: and most Portalegre touristic in region.the north, The ÉvoraAlentejo in the centre, the southern part of the Setúbal district bordering the Atlantic Ocean, warm climate with summer temperatures up to 35°C and maximum winter tem- and Beja in the south at the border to the Algarve. The Algarve has a year round dry summers up to 40°C, and relatively cold winters, when frost and snow are notperatures unusual. of The15°C. western The Alentejo and southwestern has a much part more of Portugalsevere climate: has a strong very hotAtlantic and summerclimatic influence,2008 and resultingin spring in2009. mild winters and not too hot summers. Here we present our results of two field trips to the Alentejo and Algarve in Material & Methods and from 22-iv-2009 to 04-v-2009 to the two southernmost regions of Portugal, Odonata were investigated during two field trips from 24-vi-2008 to 24-vii-2008 a daily list of localities to be visited was selected. This selection was based on the Alentejo and Algarve. With the help of topographic maps (1:25,000) of Portugal, water,most obvious at gravel suitable banks, inlocalities and above for the the bank occurrence vegetation of dragonflies and in the surroundings.in the region Thewe were survey passing lasted by. until At eachwe presumed locality we it assearched thoroughly for adult investigated, dragonflies or asabove long the as - no new species were found anymore. Most species were identified through bin- radicallyoculars. Individuals for exuviae thator larvae. are difficult For some to identifyspecies welike collected females, voucher tenerals specimens and rarer thatspecies are werepreserved caught in with GDK’s an collection. insect net for determination. We only searched spo Localities twice,We checked once inapproximately summer 2008 200 and places once for in springthe presence 2009; ofone Odonata site was and even were visited able threeto record times, dragonflies twice in summerin 112 different 2008 and localities once in (Fig. spring 1). Five2009, of andthese one were place visited was visited twice in spring 2009. Forty-nine of the sites were situated in the Algarve, withand 63 Odonata in the Alentejorecords (see (Portalegre Appendix 15, 1), Beja the 35,name Setúbal of the 13). nearest In the village few placesand topo we- visited in the Évora district,
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