Bulrushes of the genus Bolboschoenus are robust, ecologically important sedges occurring in wetlands, including intertidal marshes and mudflats. Despite their importance and multiple serious threats ...to their habitats, estuarine Bolboschoenus species remain poorly known. We conducted herbarium and field research in order to document historic and current geographic distributions, characterize the habitats, and assess the conservation status of Bolboschoenus species in the Hudson River Estuary, New York, U.S.A. Three species of Bolboschoenus grow in intertidal zones in the Hudson Estuary. Bolboschoenus fluviatilis occurs in the northern, upstream, and freshwater portion of the estuary with multi-year mean surface salinities of 0.078-2.0 ppt. Bolboschoenus robustus occupies the southernmost, downstream, and brackish to saline portion of the estuary with salinities of 4.9-16 ppt. Bolboschoenus novae-angliae occurs in the slightly to strongly brackish region between the other two species with salinities of 1.8-8.0 ppt. The geographic ranges of B. fluviatilis and B. robustus do not overlap, but B. novae-angliae has short zones of sympatry with each of the other two species. Syntopy of B. novae-angliae with each of the other two species is rare. In the Hudson Estuary, B. fluviatilis is secure, but B. novae-angliae and B. robustus are critically imperiled. Threats to future survival of Bolboschoenus species in the Hudson Estuary include competition from invasive plant species (especially Phragmites australis), eutrophication resulting from excess nutrient pollution, and habitat destruction. Our data and analyses provide critical new information for management of existing environmental problems and planned habitat restoration efforts in the Hudson River Estuary.
Restinga formations are defined as the vegetation covering sandy coastal sediments deposited during the Quaternary period, regardless their physiognomy. They are usually characterized as areas of ...confluence between plant species associated with diverse phytogeographical domains. However, detailed floristic and biogeographic studies are still required to better define their distribution patterns, the origins of their plant species, and their biogeographical affinities. In this study, we investigate the floristic similarities among restingas in Northern and Northeastern Brazil and diverse ecosystems from different Brazilian phytogeographical domains (Caatinga, Cerrado, Atlantic Forest and Amazonia). We employed multivariate analyses to investigate differences in species composition and identify floristically similar groups. While sharing species with other ecosystems, restingas exhibit unique floristic composition, representing a coastal flora. Furthermore, the restingas of Northern and Northeastern Brazil are biogeographically subdivided according to previously recognized sectors of the coast of the country. These findings underscore the complex nature of restinga ecosystems, influenced by environmental factors such as geographic distance, geology and climate. These insights contribute to a nuanced understanding of the complex relationships between restingas and their surrounding ecosystems, facilitating informed conservation efforts in the face of escalating urban and industrial expansion along the Brazilian coast.Restinga formations are defined as the vegetation covering sandy coastal sediments deposited during the Quaternary period, regardless their physiognomy. They are usually characterized as areas of confluence between plant species associated with diverse phytogeographical domains. However, detailed floristic and biogeographic studies are still required to better define their distribution patterns, the origins of their plant species, and their biogeographical affinities. In this study, we investigate the floristic similarities among restingas in Northern and Northeastern Brazil and diverse ecosystems from different Brazilian phytogeographical domains (Caatinga, Cerrado, Atlantic Forest and Amazonia). We employed multivariate analyses to investigate differences in species composition and identify floristically similar groups. While sharing species with other ecosystems, restingas exhibit unique floristic composition, representing a coastal flora. Furthermore, the restingas of Northern and Northeastern Brazil are biogeographically subdivided according to previously recognized sectors of the coast of the country. These findings underscore the complex nature of restinga ecosystems, influenced by environmental factors such as geographic distance, geology and climate. These insights contribute to a nuanced understanding of the complex relationships between restingas and their surrounding ecosystems, facilitating informed conservation efforts in the face of escalating urban and industrial expansion along the Brazilian coast.
Unidades de vegetación de la Argentina Oyarzabal, Mariano; Clavijo, José; Oakley, Luis ...
Ecología austral,
04/2018, Letnik:
28, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Existen numerosos mapas de la vegetación espontánea de la Argentina. Sin embargo, no contamos aún con uno de todo el país con una resolución que permita distinguir unidades de vegetación dentro de ...las provincias fitogeográficas descriptas por Cabrera (1976). Analizamos las descripciones de vegetación publicadas en las últimas décadas, con especial atención sobre aquellas que produjeron mapas fisonómico-florísticos. Como resultado de ese análisis, presentamos aquí un mapa fisonómico-florístico de la vegetación espontánea de la Argentina que muestra la heterogeneidad dentro de provincias fitogeográficas. El mapa tiene 50 unidades de vegetación como subdivisiones de las provincias fitogeográficas y el ecotono descritos con anterioridad, acompañadas de una breve descripción de la fisonomía y composición florística. Proponemos una nomenclatura de las unidades de vegetación según el tipo de vegetación espontánea dominante y especies características, y presentamos material cartográfico electrónico.
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