1,720,968 research outputs found
Boschi frammentati nei territori comasco, lecchese e milanese : problematiche fitosociologiche e stato di conservazione
No full textSerie dinamica del bosco a Rovere: il caso del Parco nazionale Val Grande (VCO)
No full textViene ricostruita la serie dinamica del bosco a rovere nel
Parco Nazionale Val Grande (VCO), quale caso di studio esportabile
a tutta l’area prealpina occidentale suboceanica, per analogia di clima
e substrato. Sono state cartografate, in ambiente GIS, le aree di pertinenza
della serie sulla base delle caratteristiche climatiche e fi siche del
territorio. Entro tali aree sono stati effettuati 48 rilievi fi tosociologici
che hanno compreso tutti gli stadi serali della vegetazione, per poi procedere
con l’analisi delle fi tocenosi individuate e la loro interpretazione
in chiave dinamica. Risultato dello studio è l’individuazione di sei fi -
tocenosi, quattro delle quali (pteridieti, calluneti, betuleti, rovereti) fra
loro collegate da un legame dinamico, suggerito da analisi fl oristiche
quali-quantitative sull’abbondanza delle specie e dall’analisi dei parametri
ecologico-stazionali tramite CCA.Ecological succession of sessile oak woods: Val Grande
National Park (Italian Western Alps) as a case study. We assessed the
ecological succession of sessile oak (Quercus petraea) woods in Val
Grande National Park (Verbano-Cusio-Ossola, Italian Western Alps), as
an example available for all the western prealpine insubric area. With
GIS we have deduced the map of the areas of pertinence of Quercus
petraea, based on climatic and physical characteristics of the territory.
Within these areas we carried out 48 phytosociological relevés according
to Braun-Blanquet method, assessing all stages of the ecological succession.
As a main result the Cluster Analysis individuated 6 phytocenoses
and 4 of the them (Pteridium aquilinum grasslands, Calluna vulgaris
moors, Betula pendula woods, Quercus petraea woods) have a dynamic
link suggested by quali-quantitative analysis about species ecology and
abundance and by several environmental parameters analyzed by CCA
Effetti della frammentazione sulla biodiversità vegetale delle formazioni boschive in ambito antropizzato
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Ecological thresholds in herb communities for the management of suburban fragmented forests
No full textFragmentation is a major cause of biodiversity loss. The relationship between fragmentation and biodiversity might be non-linear, due to the presence of ecological thresholds; however, the application of the threshold concept on the conservation of herb biodiversity has received limited attention. We assessed the relationship between a pool of woodland indicators and features of forest fragments (area, isolation, shape), and we evaluated whether ecological thresholds might provide guidelines for conservation. We performed our study in a human dominated area of northern Italy. In order to obtain a group of floristic indicators, we chose perennial herbs characteristic of the phytosociological syntaxa Fagetalia sylvaticae, Carpinion betuli and Erythronio-Carpinion, with suitable Landolt L and H index, obtained from previous relevés in reference and high-quality forests. Subsequently, we analyzed the relationship between richness of indicators and patch features recorded in a highly fragmented landscape. Generalized linear models showed that the number of forest indicators was positively related to fragment size and connectivity. Generalized Additive Models showed that the relationship between indicator richness and fragment size was non-linear, with the presence of two thresholds. The number of forest indicators increased until 35–40 ha; above this size the richness remained constant. Fragments above this threshold should be the target of conservation. Furthermore, the relationship between area and number of indicators was less steep in patches smaller than 1–1.5 ha. Patches between these two thresholds can be optimal targets of management actions, as small size increases can greatly improve their value for biodiversity. The identification of two thresholds in the relationship between patch area and indicators suggests an abrupt response to changing landscape features and provide quantitative targets for conservation
Recupero di biodiversità in ambiente urbano: il progetto di riqualificazione del Parco delle Cave (Comune di Milano)
No full textFringe parks, green spaces and urban forestry in Milano (Italy): state of the art and future development
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