999 resultados para Marsh ecology.


Relevância:

70.00% 70.00%

Publicador:

Resumo:

Issued August 1977.

Relevância:

70.00% 70.00%

Publicador:

Resumo:

Mode of access: Internet.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

S'han estudiat els efectes dels factors ambientals sobre el perífiton dels sistemes lenític fluctuants del aiguamolls de l'Empordà. L'estudi s'ha realitzat als tres nivells d'integració: nivell d'ecosistema considerant el rol del perífiton envers els altres productors primaris; a nivell de comunitat, estudiant la composició específica de les diatomees i a nivell de població estudiant la plasticitat fenotípica d'una espècie de diatomea (Nitzschia frustulum). A nivell d'ecosistema s'observa que els factors que afavoreixen el predomini dels diferents tipus de productors primaris (perífiton, fitoplàncton i macròfits) són la renovació i el grau d'eutròfia de l'aigua. A nivell de comunitat els factors determinants en la composició i distribució de les espècies de diatomees són els gradients confinament-inundació així com la productivitat del sistema. En funció d'aquest factors s'han establert 5 associacions de diatomees. A nivell de població es demostra que tant la salinitat, com la relació N : P a l'aigua com el moviment de l'aigua afecten la morfologia i ultraestructura de la valva de N. frustulum. De forma interessant s'observa que la salinitat, considerada com a factor individual, afecta N. frustulum a nivell poblacional provocant-li modificacions en la morfologia de la valva, per en canvi, no afecta a nivell de comunitat, ja que totes les espècies de diatomees presents en ambients de salinitat fluctuant són eurihalines.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Cover title.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Contract no.: DACW72-77-C-0013.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Experimental plantings to stabilize eroding shorelines in Bogue Sound in 1974 were successful. Better stands were produced on sites subject to severe wave stress by reducing transplant spacing to 1.5 to 2 feet apart. Rhizomes without well-developed culms attached were worthless as propagules within the intertidal zone. Seeding was unsuccessful due to exposure to excessive wave energy.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Cover title.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

"June 1976."

Relevância:

60.00% 60.00%

Publicador:

Resumo:

"August 1976."

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Mode of access: Internet.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Rangia and marsh clams, Rangia cuneata, R. flexuosa, and Polymesoda caroliniana, occur in brackish waters along México’s eastern coast from the northern State of Tamaulipas to the southern State of Campeche. The clams were important to the prehispanic people in the southern part of the State of Veracruz, where they were used as food and as construction material. In modern times, they are harvested for food. The fishermen wade in shallow water and harvest the clams in soft sediments by hand. Annual landings of whole clams during a recent 5-yr period, 1998–2002, were 1,139–1,695 t. The only area with a substantial ongoing clam fishery is in the Lower Papaloapan River Basin, including Alvarado Lagoon, where as many as 450 fishermen are licensed harvesters. This fishery for the Rangia and marsh clams is the most important clam fishery along México’s Gulf Coast.

Relevância:

40.00% 40.00%

Publicador:

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Tese de doutoramento, Ecologia, Faculdade de Ciências do Mar e do Ambiente, Universidade do Algarve, 2003

Relevância:

40.00% 40.00%

Publicador:

Resumo:

In this study we analyze the feeding ecology and trophic relationships of some of the main fish species (Soleidae, Moronidae, Mullidae, Sparidae, Mugilidae, and Batrachoididae) of the lower Estuary of the Guadiana River and the Castro Marim e Vila Real de Santo Antonio Salt Marsh. We examined the stomachs of 1415 fish caught monthly between September 2000 and August 2001. Feeding indices and coefficients were determined and used along with the results of multivariate analysis to develop diagrams of trophic interactions (food webs). Results show that these species are largely opportunistic predators. The most important prey items are amphipods, gobies (Gobiidae), shrimps (Palaemon serratus and Crangon crangon), and polychaete worms. The lower Estuary and associated salt marshes are important nurseries and feeding grounds for the species studied. In this area, it is therefore important to monitor the effects of changes in river runoff, nutrient input, and temperature that result from construction of the Alqueva Dam upstream. (c) 2006 Elsevier Ltd. All rights reserved.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Qualitative analyses of available photographs and maps of Merritt Island, Florida provide a large-scale, historical perspective of ecological changes of the marshes in the vicinity. Sites that deserve closer scrutiny can be identified. Secondarily, such an analysis provides a geographical orientation essential for communication not only between newcomers and those familiar with the area, but also among those familiar with the area but who refer to sites by differing methods. Photographs and maps from various sources were examined. Below are listed what we consider to be the most useful subset of these for ecological and geographical assessment of salt marsh impoundments on Merritt Island, Florida. (Document has 25 pages.)