Scale Perspectives on Avian Diversity in Western Riparian Ecosystems

Abstract

Conservation of riparian vegetation in westernNorth America ha~ in parg emphasized providing habitats for a locally diverse avifaunat Site diversity, especially reia. tire to the number of species preseng is generally high within riparian avifaunas. Between-habitat diversity changes across a watersheag with riparian species assemblages differ. ing most from upland assemblages at the highest and lowest elevation~ This pattern can be attributed to enhanced avian movements within the riparian vegetatiorL The corridors for bird movements, in turn, facilitate faunal mixing on a broader scal~ influencing regional diversity within land-scape~ Riparian ecosystems are viewed as connectors of forests across fragmented landscape~ In western setting& however, they are highly lineartzed forests transecting watersheds between upland associations of high elevations and very different associations at lower elevation£ Regionally, riparian vegetation represents linear islands that are internally both flortstically and faunistically dynamic rather than mere bridges of homogeneous vegetation in landscape network~ The significance of riparian vegetation as habitat for western birds has been defined primartly at the local level Conservation activities fatmring site dimity are short.sightea[ however, and could have severe consequences for unique elements of riparian avifauna~ Conservation actions must evaluate how local activities alter potential dispersal opportunities for ecological-generalist versus riparian-obligate specie~ Maintaining the character and integrity of riparian avifaunas requires planning from regional and continental perspective~ Perspectivas de escala sobre la diversidad de ayes en ecosistemas riberefios del oeste Resumen: La conservaci6n de ia vegetaci6n riberefm en el oeste de Am&rica del Norte ha enfatizado en parte la provi-si6n de hdbitats para una avifauna localmente diversct La diversidad de sitiog en especial relativos al nt~mero de especies presente~ es generalmente alta en avifaunas rtbereBa~ La dtversidad entre hd.bitats cambtag a lo largo* de una cuenc~ con eusambles ae especies ri~ diflriendo rods de los ensambles de tierras altas en las elevaciones menores y mayore~ Este patr6n puede set atrihuido al realce de los movimientos de las aves dentro de la vegetaci6n ribere~ Los corredores para el movimiento de ave~ a su vez, facilitan la mezcla fauntstica a una escala mas ampit¢ tnfluenciando la diversidad regional dentro de los paisaje.z Los eco-sisterm~ ribere~os son vistos como conectores de forestas a lo largo de paisaJes fragmentado~ En ambtentes del oest¢ sin embargo, estos son forestas altamente ltnearizadas que atraviezan cuencas entre asociaciones de tterras altas de gran elevaci6n y asociaciones muy diferentes en elevaciones menore~ Regionalment~ la vegetaci6n riberegua repmenta islas tineares que son internamente dindmtcas tanto floristtca como fauntsticament~ no siendo meros puentes de ve-getaci6n homogd, nea en redes de paisajex El significado de la vegetact6n ribem~ como hdbitats para aves del...

Scale dependent biodiversity patterns in Mediterranean river catchments: a multi taxa approach

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Does riparian habitat condition influence mammalian carnivore abundance in Mediterranean ecosystems?

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