
02324nas a2200133   4500008004100000245013700041210006900178300001200247490000800259520168400267100002101951700001901972856019901991       2013                        eng d00aBryophyte diversity on Adirondack alpine summits is maintained by dissemination and establishment of vegetative fragments and spores0 aBryophyte diversity on Adirondack alpine summits is maintained b  a382-3910 v1163 a<p>Many alpine bryophytes rely primarily if not exclusively on gametophytic fragments for reproduction. The dispersal role of these fragments, however, has not been adequately addressed. The objective of this study was to determine the extent to which fragments disperse on alpine summits and the reproductive viability of those fragments. Airborne diaspores were collected from early spring snow deposits in 2008, 2009, and 2010 from the summit of Mt. Marcy, and from summer propagule traps placed on the summits of Mt. Marcy and Algonquin Peak in 2009 and 2010. All fragments collected were identified to genus and/or species, when possible. To test for reproductive viability, fragments were grown in nutrient agar under ambient conditions for a period of 17 weeks. To detect the presence of spores, collected debris was surface sterilized and cultured on separate dishes containing nutrient agar. A total of 6130 gametophytic fragments, representing 26 species, were collected. Collections were dominated by individual leaves (65%) and leafy branch fragments (32%). Up to 20% of fragments collected were found to be viable, with the majority of growth originating from stem tissue. In contrast, spore production was found to be uncommon to rare. The results of this study provide evidence that Adirondack alpine bryophyte populations are maintained by the production and dissemination of gametophore fragments during both winter and summer months, with infrequent spore production events, perhaps episodically when weather conditions are most suitable. Data also suggest that vegetative propagules may travel longer distances on these summits than originally predicted.</p>
1 aRobinson, S., C.1 aG., Miller, N.  uhttps://bioone.org/journals/the-bryologist/volume-116/issue-4/0007-2745-116.4.382/Bryophyte-diversity-on-Adirondack-alpine-summits-is-maintained-by-dissemination/10.1639/0007-2745-116.4.382.full01968nas a2200241   4500008004100000245010800041210006900149300001200218490000800230520122600238653002501464653001701489653001501506653002301521653001501544653002201559100002101581700002301602700002301625700001901648700002101667856003801688       2010                        eng d00aA 23-Year Assessment of Vegetation Composition and Change in the Adirondack Alpine Zone, New York State0 a23Year Assessment of Vegetation Composition and Change in the Ad  a355-3770 v1123 a<p>The Adirondack Mountains of New York State hold some of the southernmost communities of alpine vegetation in the eastern United States. Containing the greatest concentration of rare and endangered species in New York State, this ∼12,000-year-old ecosystem is important to understanding the ecological history of northeastern North America. In order to monitor floristic and vegetational shifts over time, 11 permanent transects were established in 1984 on four summits (Wright, Algonquin, Boundary, and Iroquois) of the MacIntyre Range in the Adirondack High Peaks region. Using the point-intercept method, all 11 transects were sampled in 1984, 1994, 2002, and 2007. Vegetation composition changed significantly over the 23-year period, with an overall decrease in bryophytes/lichens and an increase in vascular plants, indicating that vascular plants were replacing bryophytes, particularly in areas not disturbed by hikers. Community similarity was high among all transects, and increased with time for vascular plants as they became more abundant, indicating a successional convergence. Compositional shifts may also reflect effects of global warming and atmospheric deposition on alpine plant communities.</p>
10aAdirondack Mountains10aalpine flora10abryophytes10apermanent transect10asuccession10avegetation change1 aRobinson, S., C.1 aKetchledge, E., H.1 aFitzgerald, B., T.1 aRaynal, D., J.1 aKimmerer, R., W.  uhttp://dx.doi.org/10.3119/09-03.1