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Remote Sensing Measures Restoration Successes, but Canopy Heights Lag in Restoring Floodplain Vegetation
摘要： Wetlands worldwide are becoming increasingly degraded, and this has motivated many attempts to manage and restore wetland ecosystems. Restoration actions require a large resource investment, so it is critical to measure the outcomes of these management actions. We evaluated the restoration of floodplain wetland vegetation across a chronosequence of land uses, using remote sensing analyses. We compared the Landsat-based fractional cover of restoration areas with river red gum and lignum reference communities, which functioned as a fixed target for restoration, over three time periods: (i) before agricultural land use (1987–1997); (ii) during the peak of agricultural development (2004–2007); and (iii) post-restoration of flooding (2010–2015). We also developed LiDAR-derived canopy height models (CHMs) for comparison over the second and third time periods. Inundation was crucial for restoration, with many fields showing little sign of similarity to target vegetation until after inundation, even if agricultural land uses had ceased. Fields cleared or cultivated for only one year had greater restoration success compared to areas cultivated for three or more years. Canopy height increased most in the fields that were cleared and cultivated for a short duration, in contrast to those cultivated for >12 years, which showed few signs of recovery. Restoration was most successful in fields with a short development duration after the intervention, but resulting dense monotypic stands of river cooba require future monitoring and possibly intervention to prevent sustained dominance. Fields with intensive land use histories may need to be managed as alternative, drier flood-dependent vegetation communities, such as black box (Eucalyptus largiflorens) grasslands. Remotely-sensed data provided a powerful measurement technique for tracking restoration success over a large floodplain.
关键词： chronosequence,environmental flows,fractional cover,land use,floods,cultivation,drought
更新于2025-09-09 09:28:46
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Physiological Response to Different Irradiation Regimes during Barley Seedlings Growth Followed by Drought Stress under Non-Photoinhibitory Light
摘要： Differences in physiological response of barley seedlings cultivated under low (LI, ~65 μmol m-2 s-1) and elevated irradiation (EI, ~450 μmol m-2 s-1) to upcoming drought were evaluated. After ten days of cultivation, drought stress was induced under LI by withholding water and was defined as: mild stress (MS), severe stress (SS), extreme stress (ES) and control (C, well watered). Decreased relative water content (RWC) in both LI and EI grown plants was associated with increased lipid peroxidation (TBARS) and electrolyte leakage (%EL) as well as with decreased total chlorophylls content at SS and ES. Antioxidative response to drought was, generally, indicated by higher accumulation of free proline, increased activities of catalase (CAT), guaiacol peroxidase (GPOD) and ascorbate peroxidase (APX). Even the majority of estimated physiological and biochemical parameters showed no differences between investigated light regimes before drought stress induction, the LI grown plants responded on drought by adjustment of the photosynthetic apparatus to prevent photoinhibitory oxidative damage. Photosynthesis downregulation in EI grown plants under ES was revealed due to reduced values of maximum quantum yield of photosystem II (Fv/Fm) and performance index (PIABS) showing that acclimatization to EI conditions lowered their tolerance to the following drought stress although it was applied under low irradiation (LI). Therefore, those plants had reduced capability to cope with the challenge of upcoming drought stress showing more pronounced cellular oxidative damage (SS and ES), less efficient and almost dysfunctional photosynthetic apparatus in extreme drought (ES).
关键词： antioxidative response,photosynthesis,Hordeum vulgare,light regime,drought stress,lipid peroxidation
更新于2025-09-04 15:30:14