Research Article Demographic Analysis of Cornulaca Monacantha Delile Population in Asir Region, Saudi Arabia
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Egypt. J. Exp. Biol. (Bot.), 7(1): 67 – 78 (2011) © The Egyptian Society of Experimental Biology RESEARCH ARTICLE Mohamed A. El-Beheiry Kamal H. Shaltout DEMOGRAPHIC ANALYSIS OF CORNULACA MONACANTHA DELILE POPULATION IN ASIR REGION, SAUDI ARABIA ABSTRACT: The present paper aims to study the INTRODUCTION: demography and growth strategy of Cornulaca The amount of vegetation and the ratio monacantha Delile population under natural and of living to dead plant material in any habitat experimental conditions in Asir region, Saudi at any time point depend upon the balance Arabia (in terms of size structure, natality, obtaining between the processes of mortality, and demographic flux) and to assess production and destruction. Even within one its standing crop and the correlation between its environment, there may be considerable population characters and the prevailing variation in the mechanisms, which bring environmental variables. Thirty permanent about the destruction of vegetation stands were established to represent the components. In addition to natural microvariations in five habitats, where C. catastrophes (e.g. floods and wind storms) monacantha inhabits. In each stand, the height and the drastic forms of human impact (e.g. from the ground and the average diameter of the canopy for each C. monacantha individual were ploughing, moving, trampling, and burning), estimated monthly and its volume was account must be taken for more subtle effects calculated as a cylinder. The results showed such as those due to climatic fluctuations, significant variation in its growth variables in decomposing organisms, pathogens and relation to habitat types. The growth follows a herbivores (Grime, 2002; Morales and Carlo, seasonal pattern, where the highest values for 2006), most growth variables were obtained during The struggle for existence among plants Marsh and April, while the lowest during is, to a large extent, the struggle to grow in October and November. The plant has two the face of competition from neighbors. Thus, peaks of mortality: the first in January mainly the question of how competition alters the due to heavy death of the seedlings and growth of plants is central to understand the juveniles, while the second in June associated role of competition among plants in nature. with the end of its life cycle. Its size structure Field removal studies (reviewed by Goldberg was characterized by the preponderance of the young individuals comparing with the old ones. and Barton, 1992; Bleher et al., 2002; Regarding the density effect, the individuals Cordeiro and Howe, 2003) usually detect were bigger and had more leaves under low competition, but that is only the first step than under high density. Density affected also towards understanding its role. While the pattern of leaf distribution, length and numerous studies have attempted to measure number of branches and internodes. the influence of competition on plant size or growth over one or several independent intervals, few have attempted to evaluate the KEY WORDS: influence of competition on individual plant Architecture, Competition, Mortality, Natality, growth curves (Wichmann, 2001). Phytomass, Demographic flux In order to study the influence of the environment on plant growth it is necessary to CORRESPONDENCE: develop analytic techniques that break down Mohamed A. El-Beheiry the crude phenomenon of 'growth' into Botany Department, Faculty of Science, Tanta University, components. Growth itself may be expressed 31527 Tanta, Egypt in a variety of ways and it has become E-mail: [email protected] customary to consider the phenomenon as best described by the increase in dry weight, Kamal H. Shaltout although in some ecological situations other Botany Department, Faculty of Science, Tanta measures such as height may be more useful University, 31527 Tanta, Egypt (Bazzaz and Harper, 1977). Plant grows by the progressive accumulation of repeated elements: leaves, buds, internodes, branches, and flowers, which together make up modules. ARTICLE CODE: 09.02.11 Demographic studies have included leaves of herbs (Garbutt and Bazzaz, 1983) and trees ISSN: 1687-7497 On Line ISSN: 2090 - 0503 http://www.egyseb.org 68 Egypt. J. Exp. Biol. (Bot.), 7(1): 67 – 78 (2011) (Prior et al., 2004, 2009). Other components have also considered buds (Maillette, 1982), shoots (White, 1980) and branches (McGraw and Garbutt, 1990). Interactions between the effects of habitat conditions and competition are expected to be common in natural plant communities. This related to factors affecting the intensity of competition, such as the number of individuals (Cordeiro and Howe, 2003), plant density and spatial structure (Bleher et al., 2002), productivity (Turkington et al., 1993; Kadmon, 1995), and habitat fragmentation (Neal, et al., 2010) may vary considerably between one habitat and another, even at small spatial scales. Currently, scientists are investigating how management recommendations based on spatial population models differ from those based on non-spatial models (Shea, 2004). Fig. 1. Map showing the sites from which plants were collected.(*) Therefore, spatial population models have been developed that bring together knowledge Study Area: about a species local demography and The study area is situated in the dispersal behavior (Jeltsch et al., 2008). southwestern region of Saudi Arabia. It is The present paper aim to study the about 90 km east of the Red Sea and 220 km demography and growth strategy of C. north of Yemen. It is unique in its environment monacantha populations under natural and and plant life and belongs to the greater Afro- experimental conditions in Asir region, Saudi Arabian shield, which is a part of the Arabia (in terms of size structure, natality, Precambrian crystalline plate (Schmidt et al., mortality, and demographic flux) and to 1978). The landscape is featured by rolling assess its standing crop and the correlation lands, rocky hills, wadis, and permanent wet between its population characters and the lands represented by a human-made lake prevailing environmental variables. The known as Lake Abha (El-Beheiry, 2007). This following questions were addressed: (1) Is the region supports different urban habitats such variation in local density observed in the field as road sides, waste grounds, hill sides, canal an important influence on variation in the terraces of sandy soil with small rocks and growth of C. monacantha individuals?, (2) If saline lands, where C. monacantha competition is not a major cause of size populations have developed in extensive variation in C. monacantha populations, what stands. Soil in these habitats is sandy mixed with small sized rocks, varied from 56 to 85%. other factors may account for the variation -1 observed in the field? Soil salinity varies between 4.8 mS cm in the saline lands and 1.4 mS cm-1 along terraces Study species: of high way roads (El-Beheiry, 2006). C. monacantha is a blue green intricate The climate of the southwestern region shrub, with short leaves, recurred, tapering is generally arid to hyper-arid. It is influenced from a clasping base into a rigid spine and by Saudi Arabia’s unique topography; grows on sandy and stony grounds. It is an mountains in the west bordering the Red Sea erect plant, growing up to 1 meter under and desert land in the interior eastwards. favorable conditions. It is a Saharo-sindian Long-term averages of climatic records at two species found in North Africa, Nubia, Arabia, stations distributed in the study area (Abha Iran and Pakistan (Baluchistan). In Saudi and Al-Soudah) indicate slight variations Arabia, it is distributed in southern Red Sea among sites. Rainfall is recorded throughout coastal regions (Fig. 1). This hardy shrub the year, especially during spring and favours sandy soil, but grows also with a summer. Mean annual rainfall for Abha is moderate content of gypsum and salt. It is 342.3 mm and for Al-Soudah is 640.6 mm. In situated in a hilly area, which drops gradually Abha, the mean maximum temperature is to the east (Abulfatih, 1992; El-Beheiry, o o 20.4 C and the minimum is 12.8 C. In Al- 2006). It is used as a medicinal plant for liver Soudah Mountains, the mean maximum problems and jaundice, as a hepatic and a o temperature is 17.3 C and the minimum is purgative. It is an excellent pasture for o 9.5 C. Mean annual and mean maximum wind camels despite the spines on the leaves, it -1 speed for Abha are 11.3 and 12.9 km hr ; also has a beneficial purgative effect for -1 while for Al-Soudah are 11.6 and 13.4 km hr camels, as well as helping milk production. It (Anonymous, 2000). is also used as a remedy for scabies (Boulos, 1983; Baba Aissa, 1999). ISSN: 1687-7497 On Line ISSN: 2090 - 0503 http://www.egyseb.org El-Beheiry & Shaltout, Demographic Analysis of Cornulaca monacantha Population 69 of individuals) were determined monthly. At MATERIAL AND METHODS: the end of the calendar year, the new Demography and population structure: successfully established individuals for each habitat were considered as input to its Thirty permanent stands were population. This was referred to as the annual established in the study area to represent the population natality. The annual mortality of micro variations in the five habitats in which the different shoots was also determined. The C. monacantha occurs: roadsides, waste amount of change in C. monacantha grounds, hillsides, canal terraces and saline populations (demographic flux ratio) was lands. The first four habitats were represented o o ´ estimated following the equation of Peter's in three locations (Abha (42 36´ E, 18 13 o o ´ (1980) (cf. Shaltout and El-Beheiry, 2000) as: N), Khamis Mishayt (42 49´ E, 18 16 N) and o o ´ flux ratio = change/flux = (N-M)/(N+M), where Al Qarah (42 46´ E, 18 06 N), while that of N and M are the number of emerged and dead the saline lands was represented only in o o ´ individuals in a permanent plot at a certain Ashuqaiq (42 03´ E, 17 49 N) (Fig.