Species–area relationships in isolated coastal sandy patches: Implications for the conservation of beach–dune flora in a rocky coastal region of western Japan

Abstract

Questions In many places worldwide, dune vegetation has rapidly declined owing to the expansion of various land uses, which pose a serious threat to many native dune plant species. A better understanding of species–area relationships in coastal sandy patches (i.e., beaches and dunes) is valuable for designing effective management strategies for the conservation of beach–dune flora in coastal regions. We investigated how the area and other attributes of sandy patches affect the number of species (dune, inland, and alien species) and whether the occurrence of all dune species is area‐dependent. Location Sandy coast of San'in Kaigan National Park, western Japan. Methods All vascular plants at 43 sites (sandy patches) were recorded. Using generalized linear models, we analyzed the relationships of the area and other attributes of sandy patches with the number of species and the relationship between the area of sandy patches and the occurrence (presence/absence) of each dune species. Results Larger sandy patches maintained a greater number of dune species and harbored some nationally threatened ones. The number of inland and alien species also increased with an increasing area of sandy patches, although the effects of other size and site attributes varied; shoreline length, beach–dune height, and high openness of the beach were selected as important positive factors for the number of dune species. Furthermore, most dune species in herb and dwarf shrub zones were area‐dependent and tended to occur in larger sandy patches, whereas some species of the tidal drift zone, including locally threatened dune species, were area‐independent. Conclusions Effective conservation of beach–dune flora demands not only the protection of larger sandy patches but also the selective preservation of sandy patches with better developed dunes. Moreover, the maintenance of unstable habitats for area‐independent dune species is important.

Synanthropisation of coastal vegetation in southern Spain

“…Firstly, it is important to protect the entire dune system, regardless of its species richness, as there are areas of low richness and high uniqueness such as the upper part of the beach (Acosta et al, 2009;Kuroda & Sawada, 2019). The declaration of vegetation micro-reserves -a protection figure that already exists in several regions of Spain-in well-preserved coastal areas, such as the one studied, would be highly recommended.…”

“…Coastal dunes are ecosystems of high ecological value, but fragile and often overexploited by beach tourism (Carboni et al, 2009;Tordoni et al, 2018;Kuroda & Sawada, 2019;Sarmati et al, 2019). An indicator of their value is the inclusion of most coastal habitats in the European Union (EU) Directive 92/43/EEC, as EU interest habitats, and in the European Red List of Habitats, such as the Mediterranean coastal dune grassland (B1.4b), endangered and present in southern Spain (Janssen et al, 2016).…”

“…The main causes of coastal vegetation disturbance are the construction of houses, hotels, parking lots and tracks, trampling by visitors and vehicular traffic (Hylgaard & Liddle, 1981;Andersen, 1995;Kutiel et al, 2000;Lemauviel & Rozé, 2003;Martínez et al, 2004;Santoro et al, 2012;Malavasi et al, 2013;Šilc et al, 2017;Kuroda & Sawada, 2019;Giulio et al, 2020;Zhang et al, 2020). Significant consequences of these threats are the physical destruction of vegetation and synanthropisation; the greater the accessibility of the area and the fragmentation of the vegetation, the greater the degradation and synanthropisation (Muñoz et al, 2011;Farris et al, 2013).…”

Effects of temperature on seed dormancy and germination of the coastal dune plant Viola grayi: germination phenology and responses to winter warming

“…Seeds were collected on a sand dune in Kyotango City (35°30.6′–35°46.8′N, 134°51.2′–135°13.8′E) in the eastern part of the San'in region, western Honshu. Viola grayi is found on several sand dunes in this region (Kuroda and Sawada, 2019) and grows mainly in the V. rotundifolia community (Kuroda and Tetsu, 2017). The area where seeds were collected is near the southern limit of the distribution area of this violet species.…”

Effects of sand burial on seedling growth of the coastal dune plant Viola grayi: Tolerance and adaptive responses to sand accretion

“…These include V. grayi , which primarily grows on coastal sand dunes located in the Sea of Japan side of Honshu and Hokkaido (Akiyama et al, 1999; Kadota, 2016). This violet species consists of dune vegetation, along with other dune species such as Calystegia soldanella (Convolvulaceae), Ixeris repens (Asteraceae), Carex kobomugi (Cyperaceae), Glehnia littoralis (Apiaceae), Linaria japonica (Plantaginaceae), Ischaemum anthephoroides (Poaceae), and Vitex rotundifolia (Lamiaceae) (Kuroda & Tetsu, 2020).…”