Restoration ecophysiology: an ecophysiological approach to improve restoration strategies and outcomes in severely disturbed landscapes

Photochemical attributes determine the responses of plant species from different functional groups of ferruginous outcrops when grown in iron mining substrates

Environments originating from banded iron formations, such as the canga , are important reference ecosystems for the recovery of degraded areas by mining. The objective of this work was to evaluate if the relationship between morphofunctional and photosynthetic attributes of native canga species from different functional group results in distinct responses when grown in iron mining tailings substrate. The experiment was carried out with species belonging to different functional groups: a widespread semi-deciduous tree-shrub, Myrcia splendens ; an endemic deciduous shrub, Jacaranda caroba ; and a nitrogen-fixing herbaceous species, Periandra mediterranea . The species were grown in two conditions, reference soil and iron ore tailing. Despite belonging to different functional groups when grown in tailings, the morphofunctional attributes presented similar responses between species. M. splendens was the species most affected by the conditions imposed by the iron ore mining tailings, with decreased light-use efficiency and electron transport. P. mediterranea had satisfactory growth and maintenance of photosynthetic attributes. J. caroba growing in the tailings increased the effective quantum yield of PSII. The photochemical and growth assessments were able to better explain the adaptive strategies developed by the species, guaranteeing a greater chance of success during the rehabilitation of mining substrates.

Functional traits and drought strategy predict leaf thermal tolerance

Heat stress imposes an important physiological constraint on native plant species-one that will only worsen with human-caused climate change. Indeed, rising temperatures have already contributed to large-scale plant mortality events across the globe. These impacts may be especially severe in cities, where the urban heat island effect amplifies climate warming. Understanding how plant species will respond physiologically to rising temperatures and how these responses differ among plant functional groups is critical for predicting future biodiversity scenarios and making informed land management decisions. In this study, we evaluated the effects of elevated temperatures on a functionally and taxonomically diverse group of woody native plant species in a restored urban nature preserve in southern California using measurements of chlorophyll fluorescence as an indicator of leaf thermotolerance. Our aim was to determine if species' traits and drought strategies could serve as useful predictors of thermotolerance. We found that leaf thermotolerance differed among species with contrasting drought strategies, and several leaf-level functional traits were significant predictors of thermotolerance thresholds. Drought deciduous species with high specific leaf area, high rates of transpiration and low water use efficiency were the most susceptible to heat damage, while evergreen species with sclerophyllous leaves, high relative water content and high water use efficiency maintained photosynthetic function at higher temperatures. While these native shrubs and trees are physiologically equipped to withstand relatively high temperatures in this Mediterranean-type climate, hotter conditions imposed by climate change and urbanization may exceed the tolerance thresholds of many species. We show that leaf functional traits and plant drought strategies may serve as useful indicators of species' vulnerabilities to climate change, and this information can be used to guide restoration and conservation in a warmer world.