Sie können Bookmarks mittels Listen verwalten, loggen Sie sich dafür bitte in Ihr SLUB Benutzerkonto ein.
Medientyp:
E-Artikel
Titel:
Experimental Evidence for Factors Maintaining Plant Species Diversity in a New England Salt Marsh
Beteiligte:
Hacker, Sally D.;
Bertness, Mark D.
Erschienen:
Ecological Society of America, 1999
Erschienen in:Ecology
Sprache:
Englisch
ISSN:
0012-9658;
1939-9170
Entstehung:
Anmerkungen:
Beschreibung:
<p>Understanding the processes that maintain species diversity patterns is vital for conserving and managing communities. In this paper, we examine the effect of plant species interactions on the maintenance of plant species number across intertidal zones characterized by different soil conditions in a New England salt marsh community. In this system, plant species number is low in the high intertidal and lower middle intertidal, and high in the upper middle intertidal. To understand the causes of this unimodal pattern of change in species diversity, we experimentally tested for the influence of competition, facilitation, and physical factors across this physical gradient. We established plots with and without plant neighbors, transplanted plant species into these plots, and measured mortality, leaf area, and flower number for a single growing season. We found that competition plays a more important role in the high intertidal habitat by decreasing leaf area and flower production and causing 100% mortality of one of the species tested. In contrast, physical factors are critical in the lower middle intertidal, causing 100% mortality of three of the four species tested, with or without neighbor interactions. In the upper middle intertidal, direct positive interactions were important to the higher species number. Three of the four species had 100% mortality without neighbors but minimal mortality or leaf area loss with neighbors. These positive effects were due to one particular facilitator species, Juncus gerardi L., which ameliorates the soil conditions that develop in its absence thus allowing other species to co-occur. Without Juncus, our data predict that plant species number would not be as high in the upper middle intertidal. We show that the rise in species number in the upper middle intertidal is dependent on three co-occurring conditions: the absence of a competitive dominant, less harsh physical conditions than the lower middle intertidal, and the presence of a facilitator species.</p>