東華大學圖書館 |

Language: English

Help

回圖書館首頁

手機版館藏查詢

Back

Switch To: Labeled | MARC Mode | ISBD

Experimental Investigations into the...

Jespersen, Robert Gustav.

Linked to FindBook

Google Book

Amazon

博客來

Experimental Investigations into the Ecological Functions of Cryptogams in Alpine Plant Communities.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Experimental Investigations into the Ecological Functions of Cryptogams in Alpine Plant Communities./
Author:	Jespersen, Robert Gustav.
Description:	179 p.
Notes:	Source: Dissertation Abstracts International, Volume: 74-09(E), Section: B.
Contained By:	Dissertation Abstracts International74-09B(E).
Subject:	Biology, Ecology. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3563179
ISBN:	9781303113093

Experimental Investigations into the Ecological Functions of Cryptogams in Alpine Plant Communities.
Jespersen, Robert Gustav.

Experimental Investigations into the Ecological Functions of Cryptogams in Alpine Plant Communities. - 179 p.

Source: Dissertation Abstracts International, Volume: 74-09(E), Section: B.

Thesis (Ph.D.)--University of Washington, 2013.

Vegetation scientists and alpinists alike have long noted the impressive collection of cryptogams in alpine plant communities, yet few have endeavored to uncover what ecological roles they may have. I attempted to address the question of whether and how cryptogams affect the higher plants with which they cohabitate, using several manipulative experiments involving the soil-plant-cryptogam matrix. Studies were conducted in the alpine and subalpine zones of mountains in Washington State and Chile. In most experiments, I measured the performance of several alpine plant species in the midst of either abundant or no cryptogam cover, and I coupled this with measurements of the physical and biogeochemical status of the rhizosphere. The results of these experiments cautiously support the view that some cryptogams influence the growth of neighbor plants. Most notable were the reductions in growth of grass-like species seen in plots where fruticose (large-bodied) cryptogams were removed; Festuca contracta lost approximately 40% of its initial cover when the lichen Usnea trachycarpa was removed from the spaces between plants, and Carex scirpoidea lost approximately 10% of its initial cover when the mixture of Flavocetraria cucullata and Cetraria islandica was removed from its surroundings. These growth reductions coincided with greater leaf temperature swings and some profound changes in thermal and biogeochemical properties of the rhizosphere. In particular, all of the cryptogams with tissues extending above the soil surface (U. trachycarpa, F. cucullata - C. islandica, Polytrichum piliferum) helped buffer soil temperature extremes, and in some cases buffered leaf temperature extremes and retained soil moisture. Finally, all three cryptogam surfaces studied were associated with higher soil N and C, and both removals and additions of F. cucullata- C.islandica were associated with lower NH4-N. While the mechanisms behind the observed shifts in soil resources are unknown, microclimate data provide sufficient evidence to suspect indirect effects of temperature and moisture on mineralization processes. In summary, I found moderate evidence that cryptogams affect alpine plants, and that this influence might occur through a number of physical and biochemical pathways.

ISBN: 9781303113093Subjects--Topical Terms:

1017726
Biology, Ecology.

Experimental Investigations into the Ecological Functions of Cryptogams in Alpine Plant Communities.
LDR:03206nam 2200277 4500 001 1958114
005 20140224122717.5
008 150212s2013 ||||||||||||||||| ||eng d
020 $a 9781303113093
035 $a (MiAaPQ)AAI3563179
035 $a AAI3563179
040 $a MiAaPQ $c MiAaPQ
100 1 $a Jespersen, Robert Gustav. $3 2093102
245 1 0 $a Experimental Investigations into the Ecological Functions of Cryptogams in Alpine Plant Communities.
300 $a 179 p.
500 $a Source: Dissertation Abstracts International, Volume: 74-09(E), Section: B.
500 $a Adviser: Thomas M. Hinckley.
502 $a Thesis (Ph.D.)--University of Washington, 2013.
520 $a Vegetation scientists and alpinists alike have long noted the impressive collection of cryptogams in alpine plant communities, yet few have endeavored to uncover what ecological roles they may have. I attempted to address the question of whether and how cryptogams affect the higher plants with which they cohabitate, using several manipulative experiments involving the soil-plant-cryptogam matrix. Studies were conducted in the alpine and subalpine zones of mountains in Washington State and Chile. In most experiments, I measured the performance of several alpine plant species in the midst of either abundant or no cryptogam cover, and I coupled this with measurements of the physical and biogeochemical status of the rhizosphere. The results of these experiments cautiously support the view that some cryptogams influence the growth of neighbor plants. Most notable were the reductions in growth of grass-like species seen in plots where fruticose (large-bodied) cryptogams were removed; Festuca contracta lost approximately 40% of its initial cover when the lichen Usnea trachycarpa was removed from the spaces between plants, and Carex scirpoidea lost approximately 10% of its initial cover when the mixture of Flavocetraria cucullata and Cetraria islandica was removed from its surroundings. These growth reductions coincided with greater leaf temperature swings and some profound changes in thermal and biogeochemical properties of the rhizosphere. In particular, all of the cryptogams with tissues extending above the soil surface (U. trachycarpa, F. cucullata - C. islandica, Polytrichum piliferum) helped buffer soil temperature extremes, and in some cases buffered leaf temperature extremes and retained soil moisture. Finally, all three cryptogam surfaces studied were associated with higher soil N and C, and both removals and additions of F. cucullata- C.islandica were associated with lower NH4-N. While the mechanisms behind the observed shifts in soil resources are unknown, microclimate data provide sufficient evidence to suspect indirect effects of temperature and moisture on mineralization processes. In summary, I found moderate evidence that cryptogams affect alpine plants, and that this influence might occur through a number of physical and biochemical pathways.
590 $a School code: 0250.
650 4 $a Biology, Ecology. $3 1017726
650 4 $a Biology, Botany. $3 1017825
690 $a 0329
690 $a 0309
710 2 $a University of Washington. $b Forest Resources. $3 2093012
773 0 $t Dissertation Abstracts International $g 74-09B(E).
790 $a 0250
791 $a Ph.D.
792 $a 2013
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3563179