 |
| Titel |
Land use affects the net ecosystem CO2 exchange and its components in mountain grasslands |
| VerfasserIn |
M. Schmitt, M. Bahn, G. Wohlfahrt, U. Tappeiner, A. Cernusca |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 7, no. 8 ; Nr. 7, no. 8 (2010-08-03), S.2297-2309 |
| Datensatznummer |
250004922
|
| Publikation (Nr.) |
 copernicus.org/bg-7-2297-2010.pdf |
|
|
|
|
|
| Zusammenfassung |
| Changes in land use and management have been strongly affecting mountain
grassland, however, their effects on the net ecosystem exchange of CO2
(NEE) and its components have not yet been well documented. We analysed
chamber-based estimates of NEE, gross primary productivity (GPP), ecosystem
respiration (R) and light use efficiency (LUE) of six mountain grasslands
differing in land use and management, and thus site fertility, for the
growing seasons of 2002 to 2008. The main findings of the study are that:
(1) land use and management affected seasonal NEE, GPP and R, which all
decreased from managed to unmanaged grasslands; (2) these changes were
explained by differences in leaf area index (LAI), biomass and
leaf-area-independent changes that were likely related to photosynthetic
physiology; (3) diurnal variations of NEE were primarily controlled by
photosynthetically active photon flux density and soil and air temperature;
seasonal variations were associated with changes in LAI; (4) parameters of
light response curves were generally closely related to each other, and the
ratio of R at a reference temperature/ maximum GPP was nearly constant
across the sites; (5) similarly to our study, maximum GPP and R for other
grasslands on the globe decreased with decreasing land use intensity, while
their ratio remained remarkably constant. We conclude that decreasing
intensity of management and, in particular, abandonment of mountain
grassland lead to a decrease in NEE and its component processes. While GPP
and R are generally closely coupled during most of the growing season, GPP
is more immediately and strongly affected by land management (mowing,
grazing) and season. This suggests that management and growing season
length, as well as their possible future changes, may play an important role
for the annual C balance of mountain grassland. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|