Genetic Diversity and Relative Abundance of Cebu Black Shama (Copsychus cebuensis Steere) in Fragmented Forests of Cebu Island, Philippines

Abstract

This study determined the relative abundance of Cebu black shama (Copsychus cebuensis Steere) in selected isolated forest fragments in Cebu Island, Philippines and their genetic diversity based on 619 bp cytB gene. Mist nets were used to capture the bird in these forest fragments. Four contour feathers were plucked from the body of the caught birds, before they were released, and were stored in tubes with 70% ethanol before DNA extraction. Fifty-nine black shama (C. cebuensis) individuals were encountered from the visited territories. At least 13 black shama individuals were estimated to inhabit one hectare of forest habitat. For the first time, analyses of mitochondrial genes revealed that C. cebuensis had a long evolutionary history from an initially large and stable population that went through recent expansion resulting from a recent isolating or bottleneck event as indicated by high haplotype diversity (Hd) and nucleotide diversity (πn), i.e. Hd>0.50 and πn>0.005, and non-significant values of Tajima’s D test, Fu and Li’s D*, and Fu’s Fs statistics. It is hypothesized that this bottleneck event was habitat fragmentation. Furthermore, phylogenetic analyses of C. cebuensis supported its monophyly.

Population density and distribution of the Endangered Black Shama Kittacincla cebuensis

“…The Black Shama was previously known to occur in 35 localities in Cebu including six records in highly urbanised areas (Collar et al 1999, Paguntalan and Jakosalem 2008, Malaki et al 2013, Malaki 2015, Parilla et al 2019). A total of eight new localities was added to the distribution range of the Black Shama.…”

“…Casili in Consolacion recorded 50 individuals in 1999 (Collar et al 1999) and was among the sites converted into housing development. Five male birds were mist-netted in a wooded area close to a subdivision in Casili in 2013 (Parilla et al 2019). We also recorded the bird in a university campus in Talamban in 2014 and in a high-end subdivision in Apas, Cebu City from 2011 to 2014.…”

“…This was significantly lower than the estimated density of 5,200-5,300 individuals/km 2 (52-53 individuals/ha) in forests and mixed plantations in 2012 (Malaki et al 2013), and the 2014 estimates at 2,600-3,600 individuals/km 2 (26-36 individuals/ha) in both mixed-tree species plantations and 3,100 individuals/km 2 (31 individuals/ha) in natural forests (Malaki 2015). Parilla et al (2019) mist-netted birds using playback of Black Shama calls in four of the sites surveyed in this study. The use of Black Shama calls during point counts in breeding seasons violates the most important assumptions of the Distance sampling method (Buckland et al 2001).…”

“…“Sites” are defined here as forest patch/es and “localities” are the specific areas within the forest patch/es (sites). We used the 28 sites known to harbour Black Shama (Collar et al 1999, Gonzalez et al 1999 unpublished, Jakosalem et al 2005 unpublished, Paguntalan and Jakosalem 2008, Malaki et al 2013, Malaki 2015, Paguntalan et al 2015, Parilla et al 2019) as reference for choosing the 27 localities within the 11 sites in Cebu (Figure 1). We also compiled information on recent reports of Black Shama presence in sites where previously it had not been known to occur.…”

“…The same site was revisited in 2014 where Black Shama density was estimated at 2,600–3,600 individuals/km 2 (26–36 individuals/ha) in both mixed-tree species plantations and 3,100 individuals/km 2 (31 individuals/ha) in natural forests (Malaki et al 2015). Around the same period, mist-netting surveys in four sites in Cebu recorded a total of 45 Black Shama territories and from these, density was estimated at 1,300 individuals/km 2 (13 individuals/ha) (Parilla et al 2019). The aims of this survey were to assess habitat use and confirm or reassess the previous population density estimates and distribution of the Black Shama by covering a much wider geographical area looking for new sites and by revisiting sites previously surveyed.…”