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| Titel |
Vegetation condition assessment and monitoring in Mediterranean agropastoral regions |
| VerfasserIn |
Francesco Fava, Claudio Zucca, Paolo Roggero Pier |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250052735
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| Zusammenfassung |
| In the Mediterranean island of Sardinia pasturelands represent a major component of the landscape and livestock
farming is one of the main economic activities. Intensification of the agropastoral activities on unsuited lands
on the one hand, and land abandonment on the other are considerably affecting the structure and function of
ecosystems, leading in some case to severe land degradation processes. The development of operational techniques
for assessing and monitoring pasture condition at landscape level is therefore fundamental to implement efficient
territorial management policies and to determinate the right compromise between resource exploitation and
ecosystem service maintenance. Remote sensing technologies can significantly contribute to this task, providing
timely and increasingly cost-effective information about several land condition indicators at different spatial and
temporal scales.
The main aim of this study is the development of a pasture condition diagnostic tool at landscape scale based
on satellite remote sensing data suitable for Northern Sardinia agro-pastoral regions. Hypertemporal (16 day
composite) MODIS NDVI images (MOD13Q1-v005) at 250 m spatial resolution were analyzed to monitor the
short-term (2000-2010) temporal dynamics of pasture growth and assess the actual vegetation condition. The
deviation of the vegetation productivity estimated in a given location from the one estimated in a reference area
was used as indicator of pasture condition. Diachronic analysis of Landsat data was instead performed to assess
long-term land use/cover dynamics associated to pasture degradation patterns at high spatial resolution.
The integration of the information provided by different methodological approaches and remote sensing data
with complementary spatial and temporal scale is expected to give a reliable set of indicators of Mediterranean
pasture functionality and to improve our understanding of the main factors affecting degradation trends in the
study area. Preliminary results indicate that the high temporal resolution of MODIS NDVI time series allows
monitoring vegetation productivity as well as land surface phenological indicators These indicators are effective
in discriminating degraded pastures not only when poor conditions are related to decreasing plant cover and
productivity, as generally observed in arid and semi-arid ecosystems, but also when a change in vegetation
communities composition associated to land abandonment or over-exploitation is observed. The integration of
MODIS data with higher spatial resolution information provides additional information concerning the long-term
land use/cover history in the area, and it is necessary in highly fragmented agrosilvopastoral regions, where
MODIS images are significantly affected by “mixed pixel” problems. |
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