Surface temperature as an indicator of plant species diversity and restoration in oak woodland. (June 2020)

• Record Type: Journal Article
• Authors: Hamberg, L. Jonas; Fraser, Roydon A.; Robinson, Derek T.; Trant, Andrew J.; Murphy, Stephen D.
• Is Part Of: Ecological indicators. Volume 113(2020)
• Publication Date: 2020-06
• Subjects: Landsat -- ECOSTRESS -- Restoration -- Thermal imaging -- Biodiversity -- Monitoring; Environmental monitoring -- Periodicals; Environmental management -- Periodicals; Environmental impact analysis -- Periodicals; Environmental risk assessment -- Periodicals; Sustainable development -- Periodicals; 333.71405
• DOI: 10.1016/j.ecolind.2020.106249
• Languages: English
• ISSNs: 1470-160X

Abstract

Highlights: Relative surface temperature may be a useful indicator of plant diversity change. Increased plant species diversity decreased summer surface temperature at our sites. Restoration decreased summer surface temperature by 4.5 °C over 12 years. Diurnal temperature variability decreased by 5 °C over 8 years at our sites. The new ECOSTRESS thermal imager on ISS has great utility for ecosystem monitoring. Abstract: As ecological restoration projects increase in size and complexity, scalable indicators of biodiversity change are needed for monitoring and evaluation. Through three experiments, we tested (1) if relative surface temperature decreased over time across 31 fields initially restored from agriculture to oak woodland between 2006 and 2013, (2) if diurnal temperature variation decreased with time since restoration for the same fields, and (3) if plant species diversity affects relative surface temperature change when controlling for biomass and shade. Thermal imagery was acquired from Landsat satellites 5, 7 and 8 for each growing season in 2002–2018 (excluding 2012) and from the ECOSTRESS thermal instrument on the International Space Station (ISS) for 2018. Three of the 31 fields were surveyed annually 2007–2018 for plant species diversity, ground and canopy cover, and number of woody stems. All surface temperatures were measured in percentage difference relative to adjacent mature forest areas that exhibited stable temperature responses over time. We found (1) a mean decrease in temperature of 1.5 percentage point per year since restoration; (2) a decrease of 4 percentage points of diurnal temperature difference per year since restoration for the same fields; and (3) when controlling for ground and canopy cover, stem count, and Normalized Difference Vegetation Index, an increase of one 'effective number' of plant species diversity decreased relative temperature by 5 percentage points. These results correspond to a decrease of daytime temperature of 4.5 °C over 12 years, a decrease of diurnal temperature variation of 5 °C in 8 years and a 0.3 °C decrease per extra plant species. Our results offer compelling evidence that relative temperature has potential to be used as an indicator to measure ecosystem change resulting from restoration.