Taxonomic Diversity and Structure of Gastropods in Stations at Salvia officinalis L. (Lamiaceae) in the Gardens of Tlemcen Park (Tlemcen Mounts, Algeria)

The Tlemcen region is located in north-western Algeria and is characterized by a semi-arid bioclimate. An approach to the diversity of the malacofauna associated with Salvia officinalis was carried out in three stations belonging to this area from February to June 2015. The specific richness of the Gastropods is 9 divided into three families: Milacidae, Helicidae and Subulinidae. The second includes two subfamilies including that of Helicinae and that of Helicellinae. Two species are constant, 01 is incidental and the 06 others are very accidental. The relative importance of snails fluctuates according to the stations and according to the months and the seasons. In winter, in the first station the malacological richness is equal to 6. In February, the specific richness is relatively important in the 2nd station with a value equal to 7. Milax nigricans (Milacidae) has a frequency of 10% in station 1 and has a density of 0.1 in this same station. It is absent in the other two stations. Euparypha pisana has a frequency of 60% in station 3 and an abundance of 0.57 in this same station.


Introduction
Regarding the work on wildlife in the Tlemcen region, several of them have been undertaken on different species of host plants. In fact, in the steppe region lo-How to cite this paper: Damerdji, A. (2022) Taxonomic Diversity and Structure (Poaceae) including in particular Gastropods [1] preceded a publication on Arthropods in the same region [2]. Bioecological studies on fauna are subsequently undertaken on Ampelodesma mauritanicum in the Tlemcen region by DAMERDJI and ADJLANI [3] and DAMERDJI [4], on the doum Chamaerops humilis still around Tlemcen by DAMERDJI [5] and DAMERDJI and BOUHELLOU [6]. On Thyme, Thymus ciliatus Desf. (Labiatae) a study is made on the malacofauna by DAMERDJI [7]. On Broom (Fabaceae), a malacological study is carried out by DAMERDJI [8]. On the other hand, in the park's gardens, very little work concerning wildlife has been carried out.
Authors have worked on the taxonomy and biogeoraphy of gastropods from the Iberian Peninsula and the Balearic Islands [9] [10] [11]. Other authors have carried out studies on terrestrial molluscs in very specific regions such as the Najerilla valley [12] and the municipality of Valence [13] [14]. GOMEZ [9] has drawn up a catalog of species from the Iberian region. BIGOT and AGUESSE [15] deal with structural variations of 7 Mediterranean ecosystems highly characteristic of the Rhône delta (Camargue).
On the malacofauna proper, DAMERDJI [16] examines a bioecological study in the steppe zone of the region of Tlemcen, work that the author completes at the level of the Tlemcen Mountains [17] and taking into consideration the impact of edapho-climatic factors on the conchology characteristics of the terrestrial malacological population in the same region [18] Here again, no work has been done on the Gastropods living on Salvia officinalis, a plant of medical interest. This gap justifies the present work.

Methodology
Three parts are presented, the first concerns the choice of plant material, the second the presentation of the study stations and the third the adopted methodology which includes first the field work and then the techniques used to exploit the results obtained.

Choice of Plant Material
Sage is a perennial plant with a woody stem at the base, forming a bush sometimes exceeding 80 cm, green-whitish branches. The leaves are quite large, thick, green-whitish, and opposite; the light purplish blue flowers in loose terminal spikes, arranged by 3 to 6 in spaced whorls. The bell-shaped calyx has 5 long teeth and upper bilabial corolla in helmet and lower trilobed lip. The root of the sage is brownish and fibrous. The stem, 20 to 30 cm high, is very branchy. The leaves are opposite oblong to oval, stiff, with rounded teeth, gray blue to gray green, tomentose and decussate, velvety to the touch, thick but soft. They are up to 7 cm long. Persistent, they fall if the winter is very harsh.
The flowers are arranged in 6 to 8 whorls of 4 to 10 flowers and inflorescence on the spike. They are large (20 to 35 mm long), bilabial, with short peduncles, The fruit, in the shape of a tetrakene, is invisible, composed of fine green marbles lodged at the bottom of the involucre as soon as flowering; they will quickly turn into black seeds.
According to GUIGNARD and DUPONT [19]

Choice of Study Stations
The choice of stations is made taking into account the presence but above all the abundance of Salvia officinalis. Other factors were taken into account (altitude, slope).  The following Table 1 indicates the characteristics of the three stations studied.

Methodology
In

Ecological Indices
Among the ecological composition indices used to exploit the results, mention should be made of the frequency of occurrence, abundance or centesimal frequency.
The frequency of occurrence of a species is the ratio expressed as a percentage of the number of samples where this species is noted to the total number of samples taken: F is the frequency of occurrence of the species. P a is the total number of samples containing the species considered. P is the total number of samples taken. In terms of consistency [21] distinguishes three groups. The species in the first group are qualified as constant when they are found in 50% or more of the surveys carried out in the same community. Those of the second group are incidental because they are only present in 25% to 49% of samples. Finally, accidental species have a frequency of occurrence of less than 25%.
The relative abundance of a species corresponds to the ratio of the number of individuals of this same species to the total number of individuals of all species combined: is the relative abundance of the species considered. Na, Nb, Nc, are the numbers of individuals of species a, b, c.
The relative abundance provides information on the importance of each species compared to all of the species present.
The density of a stand is the number of living individuals of all species per unit area. Fairness (E) is defined as the ratio of calculated diversity to maximum diver-

Results
The results relate to the inventory of gastropods harvested from sage, their relative seasonal and monthly importance, and the calculation of ecological indices and the vertical distribution of these species.

Variations of the Gastropods Found in Depending on the Season
The results obtained are given in the following Figure 1.
In winter, station 1 includes 6 malacological species. The malacological richness is estimated at 3 in the second station and 5 in the third station.
In spring, the Gastropods are relatively important in the 3 rd station with a richness equal to 9. The 2 nd station has eight species. In summer, the climatic conditions becoming drier, the 3 stations include respectively only one species.

Monthly Variations in the Wealth of Gastropods
The results concerning the monthly size of the Gastropods are given in the following Figure 2.
At first glance, the Gastropods seem to be present during the various months of prospecting. In February, the 1 st presents 7 species. In June, we count only one

Monthly Variations in the Numbers of Snail Individuals Recorded on Salvia officinalis in the Three Stations
The results obtained are shown in Figure 3. It should be noted that the Gastropods decreased in the fifth and sixth month.

Exploitation of the Results by Ecological Indices
All the malacological species inventoried are taken into account for the calculation of the ecological indices. The results concerning the ecological indices are placed in Table 2.

Application of the Frequency of Occurrence to Snail Species
Two species of Gastropods are constant, namely: Euparypha pisana and Rumina decollata. Helicella virgata is an accessory species and the 6 others are very accidental including Helicella pyramidata and H. terveri.

Relative Abundance of Snails
In the present case, this criterion sheds light on the biology of the malacofauna harvested from sage.

Diversity or Shannon Index-Weaver
The data in Table 3 allows us to calculate the SHANNON-WEAVER index in the 3 stations. The Shannon-Weaver index is high in the station1. It equals 2.56 in this station. The lowest value of 1.39 is observed in the second station. Seven species are present in the first, six in the third station and 4 species in the second station.

Evenly Distributed Index Applied to Snail Species
E: fairness greater than 0.5 tends to 1 for each of the three stations studied. The population of gastropods is in balance. The 1 st station is slightly more balanced compared to the other two stations (E = 0.91). Therefore, the numbers of different species tend to be in balance with each other.

Vertical Distribution of Gastropods on Salvia officinalis
The following Table 4 shows the vertical distribution of the Gastropod species on the sage.

*At the root level
Only one malacological species has been found. It is Milax nigricans (Milacidae) which seeks certain humidity at this level.

*At ground level
This pedofauna is made up of molluscs which remain a particularly characteristic Similarly in the steppe zone located south of Tlemcen, DAMERDJI in 1996 [16] has 15 species belonging to the malacofauna while [1] only one was noted with Leucochroa candidissima. This species currently called Sphincterochila candidissima is particularly fond of limestone rocks [20]. The latter shows a strong morphological adaptation for its thick and white test which must protect it from the high temperatures that can prevail in these lawns; it closes in summer with a horny epiphragm, which protects it from diapause. It should be noted that 20 species are considered to be specific, including 14 Helicidae [27]. As an example, the 5 th ecosystem considered (the steppe zone), we find there 2 species of Helicidae (Archelix bailloni and Helicella lemoinei).
In his quantitative ecology essay on Camargue Sansouire Invertebrates, BIGOT [28] indicates the number of molluscs collected in the main environments of the Camargue. In Sansouire, the specific richness is estimated at 8. Abiotic and biotic factors remain important in the variation in the size of the shells of Sphincterochila candidissima [29]. This species has a high abundance in xerophilic medium as in El-Aricha. However, this is linked to the degradation of the environment [18]. L. candidissima is much localized in Camargue where it is known in the area of the Tour du Valat and its surroundings [30]. The population of L. candidissima in the Camargue tends to show a clear detachment of the turns of its shell [31]. ENGEL [32] indicates its presence mainly in the low and salty Sansouire with Arthrocnemum glaucum.
On the other hand, E. pisana is common throughout the Camargue where its tests are collected under the Salicornia fruticosa and harbor many invertebrates [30]. On the other hand, the impact of the edapho factors has been demonstrated -climate on the conchology characters of the population of terrestrial gastropods in the region of Tlemcen [18]. According to BIGOT [33] an important fauna representing the major part of the orders of Invertebrates and almost all the orders of known insects in Camargue, took refuge in the empty shells. These tests play a big role as shelters. Wildlife finds an ideal refuge there from the cold winter temperatures and from the heat wave. These tests are also used as a food source, or even as a place for lay and metamorphosis. In 1971 SACCHI [34] studied the comparative ecology of pulmonary gastropods from the Mediterranean and Atlantic dunes.
At the same time, it should be noted that [5] found that in winter, the specific richness of snails is high on Chamaerops humilis with 12 species. In addition, Macularia hieroglyphicula also is in winter on the Diss [4].
On Rosemary, the fluctuations are between 125 individuals in April and 31 in December [25].
The phenomenon of "clusters" is an adaptive mark pushed towards the environment for species that are not very resistant to the isolated state. It occurs every year in the Rhône delta for at least 2 or 3 weeks and sometimes over several months [15].
On Rosemary, DAMERDJI et al. [25] find the high diversity index in the 3 rd station which decreases in the 1 st station. The largest population concerns Euparypha pisana with 137 individuals in the 1 st station and 212 individuals in the 3 rd station. DAMERDJI et al. [25] found the highest equal distribution in the third American Journal of Plant Sciences station in Rosemary.
At ground level, the majority of the inventoried Gastropods are found there.
Macularia, Archelix (Helicidae) and Milax gagates are counted among the pedofauna [3]. At the Diss stem, 4 species of Gastropods are noted. These species use this part of the plant to make their epiphragm and settle there [4]. Only the species Euparypha pisana, difficult to recognize with its polymorphism is found on the stipe of the doum [5].
On the diss, we found 2 species of Helicidae considered as phytophagous. According to KHELIL [2], individuals of Leucochroa candidissima are consumers of alfa foliage. On the Doum, the leaf surface being rough, the Gastropods manufacture their epiphragms to be able to survive in extreme conditions. On the Sage, very rare are the malacological species found on the limbus.

Conclusion
The

Conflicts of Interest
The author declares no conflicts of interest regarding the publication of this paper.