The Sinai Hairstreak Satyrium Jebelia Andrew Power, Samy Zalat
Total Page：16
File Type：pdf, Size：1020Kb
Nowhere left to go: the Sinai Hairstreak Satyrium jebelia Andrew Power, Samy Zalat & Francis Gilbert Journal of Insect Conservation An international journal devoted to the conservation of insects and related invertebrates ISSN 1366-638X Volume 18 Number 6 J Insect Conserv (2014) 18:1017-1025 DOI 10.1007/s10841-014-9707-8 1 23 Your article is protected by copyright and all rights are held exclusively by Springer International Publishing Switzerland. This e- offprint is for personal use only and shall not be self-archived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com”. 1 23 Author's personal copy J Insect Conserv (2014) 18:1017–1025 DOI 10.1007/s10841-014-9707-8 ORIGINAL PAPER Nowhere left to go: the Sinai Hairstreak Satyrium jebelia Andrew Power • Samy Zalat • Francis Gilbert Received: 9 June 2014 / Accepted: 1 October 2014 / Published online: 11 October 2014 Ó Springer International Publishing Switzerland 2014 Abstract High-mountain endemics with very restricted Introduction ranges are likely to have a high risk of extinction under the various scenarios of global warming. Endemic to the high Species with narrow environmental niches often have small mountains of the St Katherine Protectorate in South Sinai or very small ranges (‘endemics’) and low local abun- (Egypt), the Sinai Hairstreak Satyrium jebelia is just such a dances (Rabinowitz 1981), although in some ancient spe- species. For the first time, its population size was estimated cialized species abundances can be high (Williams et al. and its distribution and that of its larval food plant 2009). Changes in climate over thousands and millions of (Rhamnus dispermus) were mapped. The total world pop- years are important drivers of the distribution of endemics ulation in 2012 was estimated to be 1,010 individuals, (Ohlemu¨ller et al. 2008; Dirnbo¨ck et al. 2010): the Pleis- perhaps divided into six smaller sub-populations of varying tocene glaciations and post-Pleistocene warming are well size. Its moderate dispersal ability and the relatively close known to have caused range contractions down to survival proximity of the sub-populations may indicate metapopu- refugia, followed by range expansions by some but not all lation structure, but more data are needed. Aspects of host- taxa (Hewitt 2000). In mountain regions, significantly plant and habitat quality were significant predictors of the associated with high biodiversity and endemicity (Myers presence of Sinai Hairstreaks on individual trees. No et al. 2000; and even human linguistic diversity: Axelsen immediate threats are evident except global warming: if and Manrubia 2014), past climate changes have forced current climate-change predictions for Egypt are correct, many species to higher altitudes in order to track their the quality of habitat and plant diversity will decrease in climate niche (Wilson et al. 2007; Dirnbo¨ck et al. 2010). the St Katherine Protectorate, with obvious long-term Such species can become isolated on ‘mountain-top conservation implications. islands’, out of which migration is very difficult or impossible: since migration then becomes non-adaptive, Keywords Butterfly conservation Á Mountain habitat Á many mountain endemics have evolved low powers of Monophagous herbivore Á Red Listing Á Population size dispersal (Thomas et al. 2004). As anthropogenic global warming continues, these species are being pushed even higher, restricting their available habitat even more: thus mountain endemics face a heightened risk of extinction because of these factors (Thomas et al. 2004; Ohlemu¨ller A. Power (&) Á F. Gilbert School of Biology, University of Nottingham, et al. 2008; Dirnbo¨ck et al. 2010). Nottingham NG7 2RD, UK Even within the naturally small ranges of mountain e-mail: [email protected] endemics, the sizes of patches of potential habitat are F. Gilbert important for explaining their occurrence (Aarts et al. e-mail: [email protected] 2013). Understanding the spatial structure of patches and the dynamics of their populations is crucial to a successful S. Zalat College of Arts and Sciences, Taibah University, El-Ula Branch, conservation strategy (Guiney et al. 2010), especially since El-Ula, Saudi Arabia by no means all sets of patchy populations function as 123 Author's personal copy 1018 J Insect Conserv (2014) 18:1017–1025 metapopulations (Fronhofer et al. 2012). The risks of plant as the Sinai Hairstreak (Nakamura 1975). As well as habitat loss are important, since habitat destruction differences in wing morphology, the size of the male decreases habitat area as well as the connectivity between genitalia of the Sinai Hairstreak is different. suitable sites, making it more difficult to move between The eggs of both the Blue Spot and Sinai Hairstreaks are and colonise suitable areas of habitat, and increasing said to go through a diapause with a delayed emergence extinction risk for most (but not all) species (Rueda et al. until the following spring. In the former, caterpillars hatch 2013). Such considerations may be especially important in in spring and feed on emerging flower buds and young arid environments, which are patchy and fragmented due to leaves; its caterpillars secrete a sugary substance and are the limited and patchy natural resources available, espe- tended by ants (Settele et al. 2008). Myrmecophilous cially water (Sheffer et al. 2011). relationships are common in lycaenid butterflies, with This study concerns a high-mountain Egyptian endemic about 75 % of species having an association with ants butterfly, the Sinai Hairstreak Satyrium jebelia (Nakamura (Pierce et al. 2002). However, the genus Satyrium has 1975; Lepidoptera: Lycaenidae: Theclinae), now probably fewer species with ant associations than other genera Egypt’s only known endemic butterfly species after the (Fiedler 1991). Tending ants may provide protection to the recent discovery of a population of the Sinai Baton Blue caterpillars from parasites or predators, but the benefits of Pseudophilotes sinaicus in Saudi Arabia (Dr Samy Zalat, myrmecophilous relationships are likely to be species- pers. obs.). Before this study the Sinai Hairstreak was specific (Pierce et al. 2002). It is unknown if the larvae of known only from three small sites above 2,000 m altitude in the Sinai Hairstreak are tended by ants. the South Sinai mountains, all within a 10-km radius of the town of St Katherine, in the heart of the St Katherine Pro- Study site tectorate. These data highlight it as a species urgently needing reliable assessment, likely to be Critically Endan- The St Katherine Protectorate is one of Egypt’s largest gered under the IUCN categorisation. As of 2007, there were protectorates, situated in South Sinai and spanning an area only fourteen known records, the latest from 2001 (Gilbert of 4,350 km2 (Grainger and Gilbert 2008). Known as the and Zalat 2007). The original collector and describer, Na- ‘Roof of Egypt’ the area contains all of Egypt’s highest kamura (1975), stated that the Sinai Hairstreak is on the mountains (up to Mt St Katherine at 2,643 m), with deep wing between late May and early July, and is not uncommon extensive networks of dry valleys (‘wadis’) cut throughout in areas where its larval food plant, Sinai Buckthorn the landscape. The igneous Pre-Cambrian Ring Dyke Rhamnus dispermus, occurs. The dioecious Sinai Buckthorn encompassing 640 km2 and lying at the centre of the is found more widely on mountaintops in the Middle East national park was classified by UNESCO as a world heri- (Boulos 2000), but before our study it was unknown whether tage site in 2002 for its cultural and religious importance. R. dispermus is under threat in the St Katherine Protectorate. The massif is 600 million years old and is comprised Thus here we address two questions: (a) what is the mainly of red granite (UNESCO 2002). Our study sites are distribution of both butterfly and host-plant in the St Kath- found around the high mountain peaks around the city of St erine Protectorate; and (b) how large is the total population, Katherine within the Ring Dyke. and how do butterflies move among host-plants? The mountain massif is a local hotspot of biodiversity: the flora contains Turano-Iranian relicts of the last 10,000 years of drying of the Sahara (Boulos 2000). South Materials and methods Sinai has a Sahara-Mediterranean climate with hot summers (upto36°C) and cold winters, and is the coolest area in Study system Egypt (UNESCO 2002). On average the area receives 62 mm of rainfall a year (Zahran and Willis 2009). The high The Sinai Hairstreak is probably most closely related to the mountains are sometimes covered in snow during the winter, Blue Spot Hairstreak Satyrium spini (Schiffermu¨ller) of the and snow melt provides the area with more water throughout subgenus Satyrium (Nakamura 1975), found throughout the rest of the year (Grainger 2003). The relatively high western Europe as far east as Iran (Tshikolovets 2011). amount of water available compared to the rest of Egypt has There have not been any recent studies on the phylogeny of resulted in a relatively high diversity of plants and animals, Satyrium, and the current attribution of the Sinai Hairstreak among the richest in the country, if not the richest. to the subgenus Superflua is not well supported (Gian Christophoro Bozano, pers. comm.). The Blue Spot Hair- Host-plant and butterfly distribution streak has a similar wing pattern and egg structure, as well as being relatively close geographically.