Article History
Received: 27 November 2017
Accepted: 10 January 2018
First Online: 5 February 2018
Change Date: 6 March 2018
Change Type: Correction
Change Details: After publication of the article (Tian et al. 2018), it has been brought to our attention that the date included in the caption of Figure 3 is incorrect. The caption states that the photographs were taken on “July 20, 2013” but they were in fact taken on “Sept 30, 2015”.