Pak. J. Bot., 42(1): 35-46, 2010. CONSERVATION STATUS OF CADABA HETEROTRICHA STOCKS (CAPPARACEAE): AN ENDANGERED SPECIES IN PAKISTAN HAIDER ABBAS1*, MUHAMMAD QAISER2 AND JAN ALAM3 1 Karachi Institute of Biotechnology and Genetic Engineering (KIBGE), University of Karachi, Karachi-75270, Pakistan, 2 Federal Urdu University of Arts, Science and Technology, Karachi -75300, Pakistan, 3 Karachi University Herbarium (KUH), Center for Plant Conservation (CPC), University of Karachi, Karachi -75270, Pakistan * Corresponding author: invitro.life@gmail.com Abstract The conservation status of Cadaba heterotricha Stocks in Pakistan was determined according to IUCN 2001, Red Data List Categories and Criteria. Based on four years extensive field studies including population size, geographic range and habitat. Cadaba heterotricha is classified as Endangered (EN) species in Pakistan. Introduction It is estimated that some 270,000-425,000 vascular plant species are already known (Govaerts, 2001) with perhaps a further 10-20% still to be discovered and described (Hawksworth & Kalin-Arroyo, 1995). Native plants are key components of the global biological diversity, these plants are an integral part of our ecosystem in which they are facing multiple threats i.e. habitat loss and degradation, introduction of alien species, pollution and diseases, over-exploitation and climate change (McNeely et al., 1995; Wilcove et al., 1998; Sala et al., 2000; Alonso et al., 2001; Barbosa & Marquet, 2002; Sudhersan et al., 2003). Pakistan’s scenario is not different from the rest of the world. Plant biodiversity is also under tremendous pressure due to its population explosion, unplanned urbanization, deforestation and over-exploitation of natural resources (Anon., 2000; Ahmad et al., 2005). Unfortunately, very little work has been done on threatened plants of Pakistan and extremely limited information is available on this subject (Alam & Ali, 2009). According to Nasir (1991) 580-650 flowering plant species (i.e. 12%) are expected to be threatened. Chaudhri & Qureshi (1991) reported 709 taxa as threatened plants from Pakistan. However, both these studies are manly based on field observation and literature, without any support of quantitative data. In contrast, the recent red list of IUCN (Anon., 2008) only 19 flowering plants species have been listed from Pakistan. Regarding Pakistan, previous workers have classified the plant species as threatened or rare on the basis of literature or herbarium specimen. No work has been done according to IUCN red list categories or criteria (Anon., 2001) except Alam & Ali (2009), who classified Astragalus gilgitensis Ali as a Critically Endangered (CR). Cadaba heterotricha Stocks is a shrub and a member of the family Capparaceae. It is localized in the rocky slopes of Coastal belt of Karachi from Cape-Monze to Sona Pass. It is also reported from Kenya, Ethiopia, Somalia, Yemen, Oman and Pakistan (Fig. 1). Number of workers have reported it as a rare taxon in its geographic range (Table 1). Jafri (1958 & 1974) considered it as a rare species due to its narrow distribution in Pakistan. While, Nasir (1991) classified it as an endangered species for Pakistan. The conclusion of Nasir, was purely based on literature, rather then field based observations. Fig. 1. Global distribution map of Cadaba heterotricha. 36 HAIDER ABBAS ET AL., CONSERVATION STATUS OF CADABA HETEROTRICHA 37 38 HAIDER ABBAS ET AL., In order to determine the conservation status of the Cadaba heterotricha in Pakistan, present study was under taken. Materials and Methods Twenty one field surveys were conducted from 2005 to 2008 at a regular interval. Habit, habitat, altitudinal range, population size, distribution range, impacts of multiple threats like habitat destruction, erosion, fuel wood cutting, grazing, poultry farms and invasive species have been studied for four years in the habitat. • Distribution area of the taxon was calculated by plotting relevant GPS values on the map. ArcGIS 9.2 version was used for this purpose. • Previously known localities and their adjoining areas were thoroughly surveyed to determine the exact area of occurrence and nature of distribution of Cadaba heterotricha. • Locations were recorded with the help of global positioning system (GPS). • The population size was determined by counting the mature individuals. The seedlings were also counted separately. • Nature of habitat was analysed by soil erosion, invasive species and impacts of anthropogenic activities. • Habit and life form of every associated species in the habitat was also recorded and classified according to Raunkier’s System of Classification. • Information has also been collected from native people regarding the ethno-botanical usage. Results Habit, habitat and associated species: Cadaba heterotricha is a medium size shrub (Fig. 2) and grows on slopes and cliffs of calcareous rocks up-till an altitude of 150m. However, few individuals were also recorded in plains near rocky slopes. However, individuals in the plains concentrated along stream beds. Euphorbia caducifolia Haines, Acacia senegal (L.) Willd., and Commiphora wightii (Arn.) Bhandari were found as dominant species in the habitat. In total of 29 associated species (Table 2) were observed in the habitat. Amongst these, 18 shrubs, 3 trees, 7 biennial or perennial herbs, and 1 annual herb were recorded. The dominant life form was phanerophytes (14 species) followed by chemophytes (9 species), hemicryptophytes (4 species) and therophytes (1 species). Area of distribution in Pakistan: In Pakistan, Cadaba heterotricha occupies an area of 76.96 Km2 in the coastal belt of Karachi between Cape-Monze to Sona Pass. However, in the distribution area, rocky slopes occupy less area as compared to plains (Fig. 3). Population size and mode of reproduction in the wild: The population size during 2005-2008 is given in Table 3. Maximum mature plants were found in 2005 i.e., 260 followed by 257, 254 and 251 in 2006, 2007 and 2008 respectively. During the study, no seedlings were observed on rocky slopes or cliff, however, some immature plant individuals growing of the suckers from the parent plants were found on eroded gravel plains. Initially, during two years (2005 & 2006) we could not find any young plant, while, during 2007 and 2008, 20 and 18 young plants were recorded, respectively. CONSERVATION STATUS OF CADABA HETEROTRICHA Fig. 2. Cadaba heterotricha: A, Habit; B, Flower; C, Fruits. Fig. 3. Cadaba heterotricha: A, Study area; B, distribution in Pakistan. 39 HAIDER ABBAS ET AL., 40 Table 2. Species found in association with Cadaba heterotricha from 2005 to 2008 along with their habit and life form. # Species Habit 1. Acanthaceae Family Barleria acanthoides Vahl Perennial Herb Life form Chaemaphyte 2. Amaranthaceae Aerva javanica (Burm.f.)Juss ex Schultes Perennial Herb Chaemaphyte 3. Asparagaceae Asparagus dumosus Baker Shrub Phanerophyte 4. Asteraceae Pluchea arguta Boiss. Shrub Phanerophyte 5. Asteraceae Echinops echinatus Roxb. Annual Therophyte 6. Asteraceae Pulicaria boissieri Hook.f. Shrub Chaemaphyte 7. Boraginaceae Cordia sinensis Lam. Shrub Phanerophyte Phanerophyte 8. Burseraceae Commiphora wightii (Arn.) Bhandari Shrub 9. Caesalpiniaceae Senna holosericea (Fresen.) Greuter Shrub Chaemaphyte 10. Capparaceae Capparis cartilaginea Decne. Shrub Phanerophyte Phanerophyte 11. Capparaceae Capparis deciduas (Forssk.) Edgew. Shrub 12. Chenopodiacee Salsola imbricata Forssk. Perennial Herb Chaemaphyte 13. Chenopodiaceae Suaeda fruticosa Forssk. ex J. F. Gmelin Shrub Phanerophyte 14. Convolvulaceae Convolvulus glomeratus Choisy Perennial Herb Hemicryptophyte 15. Convolvulaceae Seddera latifolia Hochst. & Steud. Shrub Chaemaphyte Phanerophyte 16. Euphorbiaceae Euphorbia caducifolia Haines Shrub 17. Gentianaceae Enicostemma hyssopifollium (Willd.) Verdoon Perennial Herb Hemicryptophyte 18. Malvaceae Senra incana Cav. Shrub Chaemaphyte 19. Malvaceae Abutilon fruticosum Guill. & Perr. Perennial Herb Chaemaphyte 20. Mimosoideae Acacia senegal (L.) Willd. Tree Phanerophyte Shrub - Tree Phanerophyte 21. Mimosoideae Prosopis juliflora (Swartz) DC. 22. Mimosoideae Acacia nilotica subsp. hemispherica Ali & Faruqi Shrub to Tree Phanerophyte 23. Papilionaceae Indigofera articulata Gouan Phanerophyte Shrub 24. Poaceae Cymbopogon jwarancusa (Jones) Schult. Perennial Herb Hemicryptophyte 25. Poaceae Chrysopogon aucheri (Boiss.) Stapf Shrub Phanerophyte 26. Rhamnaceae Ziziphus nummularia (Burm.f.) Wight & Arn. Shrub Phanerophyte 27. Salvadoraceae Salvadora oleoides Dcne. Tree Phanerophyte 28. Scrophulariaceae Kickxia ramosissima (Wall.) Janchen Perennial Herb Hemicryptophyte 29. Tiliaceae Grewia tenax (Forssk.) Fiori Shrub Phanerophyte 30. Tiliaceae Grewia villosa Willd. Shrub Phanerophyte 31. Zygophyllaceae Fagonia indica Burm. f. Perennial Herb Chaemaphyte Habitat destruction and soil erosion: The habitat of Cadaba heterotricha has a good quality stone, suitable for the construction purposes which is being excavated by and transported with help of machines. This excavation activity is going on in the entire habitat. At an average from each excavation site three trucks are loaded each day if they are filled manually but if big machines are used, then they can easily send around 15-20 truck loads per day. The crushing and excavation of stones continues throughout the year, but it reaches at its maximum during the summer because of enormous increase in demand. Soil erosion during rainy season, is another threat in the habitat. Plant individuals of Cadaba heterotricha grows very well on the plains instead of rocky slopes, but they tend to grow on the edges of the eroded land and soil erosion is accelerated due to heavy rains, thus disturbing the already restricted and specific habitat (Fig. 4). CONSERVATION STATUS OF CADABA HETEROTRICHA 41 Fig. 4. Cadaba heterotricha: A, General view of the habitat degradation due to stone excavation; B, Stone excavation and transportation activities; C, Grazing activities. Table 3. Summary of population size of Cadaba heterotricha from 2005-2008. Population size 2005 2006 2007 2008 Mature plants 260 257 254 251 Immature plants 0 0 20 18 Fuel wood cutting and poultry sheds: Another threat for the small population of Cadaba heterotricha, is its over-exploitation for fuel wood purpose. Local residents of various goths (villages) i.e., Goth Haji Usman, Goth Ahmed and other, have no access to natural gas (sui-gas) and electricity. The population of 20,000 inhabitants and increasing number of poultry farms, need fuel wood on regular basis, for cooking and maintaining temperature during winter season in poultry farms. Grazing impact: Inhabitant of the area tends to maintain a large number of livestock like goats, camel and cows, which exerts a tremendous pressure on the vegetation. Unfortunately, the situation further deteriorates before Eid-ul-Azha (A Muslim festival in which livestock are sacrificed), when local inhabitants purchase extra livestock for this upcoming event at least three to five months ahead. This seasonal increase in the number of livestock creates an immense pressure on the vegetation which is already under severe stress. More than 300 goats and 60-70 cows in the areas were counted during the field studies (Fig. 4C). 42 HAIDER ABBAS ET AL., Invasive species: The whole area has been heavily infested by Prosopis juliflora but it grows more aggressively on the plains then on the stony slopes or gravel sites. During 2005, the first year of survey, Prosopis juliflora was not found growing as gregariously as in 2008 and one can imagine the scenario in the future. Discussion and Conclusion The specific features of restriction and isolation expose the species, prone to extinction, especially in the era of rapid habitat loss or degradation (Myers, 1988; Heywood & Watson, 1995; Sala et al., 2000). Cadaba heterotricha is mostly found on rocky slopes and sandy soils with limestone silt. Our observations are in agreement with the previous workers, which have reported the species from almost similar habitats from other parts of the world (Table 1). Hence, it is suggested that Cadaba heterotricha is habitat specific and confined to a narrow distribution range. The prime cause of plant extinction around the globe is the fragmentation and disturbance of species habitat (Sala et al., 2000; Barbosa & Marquet, 2002). A large scale stone excavation and road construction activity is the major cause of disturbance and destruction in the habitat of Cadaba heterotricha. Gully erosion is causing a severe damage during rains, individuals of Cadaba heterotricha growing in sandy are found more prone to erosion than the plants found on rocky slopes and cliffs. Invasion of invasive species is widely considered as second greatest cause of species endangerment and extinction after habitat loss around the globe (Huston, 1994; Wilcove et al., 1998; Primental et al., 2001; Levine et al., 2003). Millions of hectares of rangeland have already been invaded by Prosopis juliflora. The process is still occurring in South Africa, Australia and coastal Asia (Pasiecznik, 1999) and having serious consequences on ecological, economic and social systems (Primental et al., 2000). Due to devastating effects of Prosopis juliflora, it has been included in the IUCN’s list of 100 world’s worst invasive species (Pallewatta et al., 2003). According to El-Keblawy & Al-Rawai (2007) Prosopis juliflora is causing extirpation of the native flora, resulting in the reduction of species richness and diversity. Noor et al., (1995) reported that Prosopis juliflora is playing a vital role in Pakistan in the elimination of natural vegetation due to its allelopathic effects. Prosopis juliflora was also observed as aggressively growing invasive species in the habitat of Cadaba heterotricha. However, concentration of the population was mostly found on sandy areas rather than rocky slopes. According to Pieper (1994) impact of grazing ranges from almost undetectable removal of plant material to severe depletion of vegetational resources and extensive erosion. Grazing activity was observed in the habitat, but its impact was quite prominent and devastating for Cadaba heterotricha. Uncontrolled and expanding grazing activities have a deep and long term impact on the local vegetation and it is disastrous for the local plant wealth which is already in stress. Over-exploitation of plant species for fodder and fuel wood purpose by local communities and nomads is a complex problem and a major cause of plant extinction (Hirway & Goswami, 2007; Engler, 2008). Regarding impacts of unsustainable use of plant species, no accurate information has been published (Davis et al., 1995), but there is no doubt about its consequences. In case of Cadaba heterotricha, another major concern is that, local inhabitants and commercial scale poultry farms have no access to the natural CONSERVATION STATUS OF CADABA HETEROTRICHA 43 gas and electricity for maintaining their living. Fuel wood chopping exercise is quite prominent in the habitat of Cadaba heterotricha, thus badly affecting its population. Rabinowitz (1981) suggests that those species which are found over a wide geographic range but are consistently rare throughout their distribution need immediate attention as they are more vulnerable from extinction point of view. Cadaba heterotricha is reported from Coast of Karachi to North Eastern Africa, a quite large distribution area. However, at the same time it is reported as a rare species throughout the region by previous workers (Baker, 1894; Gillett, 1944; Jafri, 1958, 1974; Miller & Moris, 1988; Tadesse, 1995; Wood. 1997; Ghazanfer, 2003; Raffaelli et al., 2003). It was first discovered by Stocks in 1852, from Sindh, Pakistan and even 157 years it is still considered as a rare species in the entire distribution range. In case of Pakistan, Jafri (1958, 1974) has clearly mentioned that it appears to be a rare species due to its narrow distribution range from Cape-Monze to Sona Pass area; moreover Nasir (1991) also considered this taxon as an endangered species for Pakistan. According to our observations, Cadaba heterotricha requires a specific habitat and grows from CapeMonze to Sona Pass It is a rare taxon according to the criteria of Rabinowitz (1981) by having specific habitat, extremely narrow distribution and rare throughout its geographic range. According to Baggs & Maschinski (2000) population size is often affected by dry periods during the growing season, when plants may not produce any viable seed and there will be no natural recruitment. No natural recruitment was observed in Cadaba heterotricha during field studies of 2005–2008. Hence, it is concluded that the population sizes of studied taxa are continuously reducing at an alarming rate, without having natural recruitment. Many threatened plant species are predisposed to threat due to their small population sizes (Rabinowitz, 1981; Kruckeberg & Rabinowitz, 1985). The conservation status of a species is mainly based on the number of mature individuals of that taxon (Anon., 2001). The current study was conducted, according to the IUCN red list categories and criteria (Anon., 2001), which describes in detail that if population size is fewer than 250 mature individuals with a continuous decline in their number along with no sub-populations, making the taxon eligible to be placed under Critically Endangered (CR) category. Cadaba heterotricha with a population size of 251, is placed under Critically Endangered category and is under threat of extirpation. These findings suggest that low population size along with continuous decline in their numbers without having any subpopulations is critical for its survival. Conservation status of a taxon is also based on the geographic range and number of localities/sub-populations (Anon., 2001). The categories and criteria clearly explain that if a taxon has less then 500 km2 extent of occurrence with one locality or severely fragmented localities should be considered as Endangered (EN) in addition to other parameters. In case of Cadaba heterotricha the extent of occurrence is 76.96 km2. From the point of view of number of localities the studied taxa is reported from single locality. Based on the small geographic range and single locality, C. heterotricha, is placed under Endangered Category. These findings according to IUCN criteria suggest that the restricted distribution range of concerned taxon in a single locality is critical for its survival. On the basis of multiple threats i.e., habitat specificity, restricted distribution range, habitat loss through commercial scale stone excavation activities, invasion of invasive HAIDER ABBAS ET AL., 44 species i.e., Prosopis juliflora, over exploitation in the form of grazing and fuel wood cutting and low population size along with negligible natural recruitment, the current study concluded that Cadaba heterotricha is highly prone to extirpation and eligible to be placed under Endangered (EN) category. In context with global biodiversity, conservation of a rare species at national level is very important. Hence, urgent conservation steps should be taken as suggest below, to avoid its extirpation from Pakistan. 9 9 9 9 9 9 9 9 The Cadaba heterotricha should be included in the Red Data list of threatened species for Pakistan. Conservation status assessment of the C. heterotricha in other countries should also be initiated to assign the category in international perspective. Efforts should be made to protect the taxon by minimizing the anthropogenic activities in the habitat (i.e. stone excavation, fuel wood cutting, grazing and poultry business). Cadaba heterotricha should be introduced in botanic gardens for public display. Seeds of the taxon should be preserved in local seed banks and also distributed to other regional conservation organizations, so that in case of any natural disaster it can be protected and recovered. 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