Persistent soil seed banks in Phacelia secunda (Hydrophyllaceae): experimental detection of variation along an altitudinal gradient in the Andes of central Chile (33 degrees S)

Citation
La. Cavieres et Mtk. Arroyo, Persistent soil seed banks in Phacelia secunda (Hydrophyllaceae): experimental detection of variation along an altitudinal gradient in the Andes of central Chile (33 degrees S), J ECOLOGY, 89(1), 2001, pp. 31-39
Citations number
48
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Environment/Ecology
Journal title
JOURNAL OF ECOLOGY
ISSN journal
0022-0477 → ACNP
Volume
89
Issue
1
Year of publication
2001
Pages
31 - 39
Database
ISI
SICI code
0022-0477(200102)89:1<31:PSSBIP>2.0.ZU;2-S
Abstract
1 It is unclear whether soil seed banks in alpine environments are a result of selection for extended seed dormancy, of ideal conditions for seed pres ervation in the soil, or a combination of both. 2 The nature of the soil seed bank was investigated in the perennial herb P hacelia secunda (Hydrophyllaceae) through reciprocal burial experiments usi ng seeds obtained from populations growing at 1600, 2200, 2900 and 3400 m a .s.l. in the mediterranean Andes of central Chile. At the four elevations, six replicates of 50 seeds each, from each of the four elevational sources, were buried at 5 cm depth in mesh envelopes, placed in wire cages to prote ct against predation. Seeds were retrieved 1,2 and 3 years after burial, an d numbers of ungerminated seeds, and of those that remained viable, were de termined. 3 At all elevations of seed burial, increasing proportions of seeds remaine d ungerminated, and proportionately more of the ungerminated seeds remained viable, as elevation of source of seed increased. For seed from low elevat ion, more seeds remained viable in the soil at the higher burial sites. How ever, for the seeds from higher elevation sources, seeds remaining viable w ere similar in number at all sites for seed burial. Half-lives of seed buri ed at the source elevation, calculated from the log-logistic distribution, increased with elevation, and ranged from 188 days at 1600 m to 354 days at 3400 m. 4 The results suggest that the propensity to form a persistent seed bank in P. secunda increases with elevation. Seeds from the highest elevations had the longest persistence, and this was largely unaffected by soil preservat ion conditions. Seeds from lower elevations survived for less time, and thi s was modifiable by preservation conditions. These results suggest that bot h selective effects and soil conditions may be involved in soil seed bank e xpression in the alpine environment.