Autor: Revista Agraria Academica

Agrarian Academic Journal

agrariacad.com

doi: 10.32406/v8n5/2025/24-32/agrariacad

Phytochemical screening, total phenolic, flavonoid content and antioxidant activity of Corallina officinalis from the Algerian coast. Triagem fitoquímica, conteúdo fenólico total, flavonoides e atividade antioxidante de Corallina officinalis da Argélia.

Abdellatif Alioui¹, Benattouche Zouaoui¹, Asmaa Belmimoun¹

^1- Department of Biology, Faculty of Natural Sciences, University of Mascara, Algeria 29000. E-mail: alioui.latifbio@gmail.com

Abstract

This research conducted a comprehensive assessment of the in vitro antioxidant properties of Corallina officinalis, a red macroalga, using extracts prepared with various solvents. The methanolic extract (ME), chloroform fraction (CF), and hexane fraction (HF) were evaluated for their antioxidant efficacy through the DPPH and (FRAP) method. Phytochemical analyses were performed to measure the total phenolic and flavonoid content, employing spectrophotometric techniques. The results indicated that the methanolic extract contained the highest concentrations of phenolics and flavonoids, succeeded by the chloroform and hexane fractions. Qualitative investigation verified the existence of essential bioactive components including phenols, flavonoids, sterols, polysaccharides, and terpenoids. The methanolic extract demonstrated superior antioxidant performance, with a DPPH radical scavenging rate of 78.71% and a reducing power corresponding to an absorbance of 1.16 at 700 nm. In contrast, the hexane extract exhibited a scavenging rate of 43.11% and an absorbance of 0.98 at the same wavelength. These findings suggest that the extracts possess significant potential for antioxidant applications.

Keywords: Corallina officinalis. Antioxidant activity. Phytochemical.

Resumo

Esta pesquisa conduziu uma avaliação abrangente das propriedades antioxidantes in vitro de Corallina officinalis, uma macroalga vermelha, usando extratos preparados com vários solventes. O extrato metanólico (ME), a fração clorofórmica (CF) e a fração hexânica (HF) foram avaliados quanto à sua eficácia antioxidante através do método DPPH e (FRAP). Análises fitoquímicas foram realizadas para medir o conteúdo total de fenólicos e flavonoides, empregando técnicas espectrofotométricas. Os resultados indicaram que o extrato metanólico continha as maiores concentrações de fenólicos e flavonoides, sucedido pelas frações clorofórmica e hexânica. A investigação qualitativa verificou a existência de componentes bioativos essenciais, incluindo fenóis, flavonoides, esteróis, polissacarídeos e terpenoides. O extrato metanólico demonstrou desempenho antioxidante superior, com uma taxa de sequestro de radicais DPPH de 78,71% e um poder redutor correspondente a uma absorbância de 1,16 a 700 nm. Em contraste, o extrato hexânico apresentou uma taxa de sequestro de 43,11% e uma absorbância de 0,98 no mesmo comprimento de onda. Esses achados sugerem que os extratos possuem potencial significativo para aplicações antioxidantes.

Palavras-chave: Corallina officinalis. Atividade antioxidante. Fitoquímicos.

Introduction

Seaweeds, often referred to as marine vegetables, form the foundation of life in aquatic ecosystems and have served various purposes, including use as fertilizer, human food, and animal feed, spanning ancient to modern times (PACHECO et al., 2020). These marine organisms are categorized into three primary groups: Chlorophyta (green seaweed), Rhodophyta (red seaweeds), and Phaeophyceae (brown seaweeds). The classification is based on their pigment composition, and these groups exhibit significant variations in their metabolite compositions (PALANIYAPPAN et al., 2023). The Mediterranean contains more than eight hundred species of algae. Algeria has nearly 1,600 km of coastline, containing considerable algal diversity. Marine algae constitute a little-explored source in Algeria, although they constitute an economic development issue (CHEMLAL-KHERRAZ et al., 2024).

Seaweed is well recognized as a significant source of bioactive compounds, including proteins, polysaccharides, lipids, and polyphenols, due to the fact that these chemicals exhibit significant antibacterial, anticancer, antioxidant, antifungal, and antiviral effects (SUNDARAMURTHY et al., 2016).

In recent years, there has been increasing scientific interest in the antioxidant phytochemicals found in macroalgae extracts, given their crucial role in disease prevention. Substances such as phenols, tannins, flavonoids alkaloids, phlorotannins, terpenoids, pigments, glycosides, and steroids contribute to the protection of algae from oxidative stress induced by reactive oxygen species in harsh environments (YUAN; WALSH, 2006; SENGUTTUVAN, 2014). These antioxidants derived from macroalgae are essential for maintaining the structural integrity of cells under environmental stress conditions (ALENCAR et al., 2016). Natural processes, such as lipid peroxidation and the generation of free radicals, are often exacerbated by exposure to prooxidants like ultraviolet radiation, air pollution, and cigarette smoke (ADAMS, 2010; HUANG et al., 2009). By inhibiting oxidative reactions, antioxidants support the maintenance of redox homeostasis within biological systems (SINHA; DABLA, 2015). Polyphenols, flavonoids, and tannins have garnered considerable attention for their capacity to neutralize free radicals, hence decreasing the probability of acquiring conditions such as cancer, hypertension, and inflammation (POHANKA, 2014; BAINS; SHAW, 1997). The marine seaweed, Corallina officinalis has been shown to have a specific phenolic content, antioxidant properties, and antibacterial properties. As a result, it may be used as a source of biologically active substances (BARBA et al., 2016).

The purpose of this research sought to quantify the phenolic and flavonoid content of Corallina officinalis obtained from the Algerian coast and to assess its antioxidant capacity.

Materials and methods

Collection of algal material

Fresh Corallina officinalis samples were collected from the Mostaganem coastline in Algeria. After an extensive rinsing using tap water, the algae were cleansed with saltwater to eliminate any material adhering to their surface. The samples were transported to the laboratory under chilled conditions to preserve their biochemical integrity. Once in the lab, the algae were air-dried at ambient temperature in a shaded area, ground into a fine powder, and stored appropriately for further analysis.

Extraction

Ten grams of the dried algae powder were weighed and subjected to cold methanol extraction. The mixture was intermittently stirred for over 48 hours, followed by filtration. The crude methanolic extract was concentrated at forty degrees Celsius under reduced pressure using a rotary evaporator. A portion of the extract was partitioned using a Soxhlet extractor, successively with hexane and chloroform, each for four hours. The concentrated solvent fractions were freeze-dried and stored until use.

Phytochemical analysis

A phytochemical constituent screening was conducted on the extracts of C. officinalis, including phenols, flavonoids, tannins, alkaloids, phlobatannins, saponins, sterols, coumarins, terpenoids, quinones, and carbohydrates, following methods established in the scientific literature (UDDIN et al., 2014; TIWARI et al., 2011).

Determination of total phenolic and flavonoid content

The Folin-Ciocalteu colorimetric technique was employed to quantify the total phenolic content. Gallic acid was utilized as the reference, and the results were expressed as milligrams per gramme of dry matter (DM) comparable to gallic acid (WOJDYLO et al., 2007). Shafii et al. (2018) devised a refined technique for quantifying total flavonoid concentration, with results expressed as mg/g DM quercetin equivalent.

An assessment of the DPPH radical scavenging activity was conducted following a previously reported approach (GYAMFI et al., 1999). After adding one milliliter of diluted extract to one milliliter of 0.4 mM methanolic DPPH solution, the mixture was incubated in the dark for thirty minutes. A control comprising only the DPPH solution was utilized for comparative purposes during the absorbance measurement at 516 nm., with a control containing only the DPPH solution for comparison. The scavenging capacity was calculated using the formula:

In this instance, “Abs” denotes the absorbance values of both the control solution and the sample solution.

FRAP assay

The ferric reducing antioxidant power (FRAP) of the extracts was evaluated according to the methodology outlined by Zubia et al. (2020). An aliquot of 0.5 mL from each extract was combined with 1.25 mL of sodium phosphate buffer (0.2 M, pH 6.6) and 1.25 mL of 1% potassium ferricyanide solution, then incubated at 50°C for 20 minutes. After cooling, 1.25 mL of 10% trichloroacetic acid was introduced, succeeded by 1.25 mL of distilled water and 0.25 mL of 10% ferric chloride solution. Absorbance was quantified, and the antioxidant capacity was articulated as milligrams of ascorbic acid equivalent per gramme of extract.

Statistical analysis

Data from three separate replicates were gathered and provided as mean values with standard deviation (SD). Statistical significance was evaluated using the Student’s t-test and the Least Significant Difference (LSD) test, with a significance threshold established at p < 0.05.

Results and discussion

Phytochemical analysis

Table 1 summarizes the phytochemical screening results for the algae extracts, revealing the presence of various bioactive constituents, such as phenols, flavonoids, tannins, sterols, terpenoids, and carbohydrates. Phenols and flavonoids were found to be the most abundant, followed by moderate levels of terpenoids, while carbohydrates and tannins were present in smaller amounts. The hexane extracts contained lower concentrations of phenols and flavonoids compared to the methanol and chloroform extracts, likely due to the limited solubility of these compounds in hexane. Similar findings by Bahammou et al. (2021) highlighted the presence of tannins, flavonoids, phenols, and steroids in C. mediterranea. Differences in bioactive compound content among studies may result from variations in algal material and extraction methods.

Table 1 – Phytochemical screening of extracts from red algae C. officinalis

(+) and (-) signs indicate the presence and absence of the phytoconstituent, respectively.

Total phenolic content

Phenolic compounds, a crucial class of secondary metabolites, are involved in vital biological processes such as antibacterial, anticarcinogenic, anti-inflammatory, and therapeutic activities. The extracts demonstrated phenolic content ranging from 2.5 ± 0.12 to 22.9 ± 0.26 mg of gallic acid equivalents (GAE) per gramme of dry weight (DW) extract (Figure 1). The methanol extract of C. officinalis exhibited the highest phenolic content (22.9 ± 0.26 mg GAE/g DW), significantly exceeding (p < 0.05) the hexane and chloroform extracts. These findings correspond with further studies suggesting that methanol extracts possess increased phenolic content (MORSY et al., 2018). Prior studies have recorded reduced levels of phenolics and flavonoids in Corallina species (ISMAIL, 2017).

Total flavonoid content

Flavonoids, another important group of phenolic compounds in medicinal plants, exhibit strong antioxidant activities (PIETTA, 2000). The total flavonoid content (TFC) was quantified as quercetin equivalents. Figure 1 shows that methanol extracts of C. officinalis had the highest flavonoid content (5.58 mg/g DW), followed by chloroform extracts (4.72 mg/g DW), and hexane extracts with the lowest (2.21 mg/g DW). This trend underscores the efficacy of methanol as an extraction solvent. The high levels of phenolic and flavonoid compounds in C. officinalis are likely responsible for its antioxidant properties. Literature comparisons revealed discrepancies in TFC values, which may be influenced by genetic, environmental, and seasonal factors, as well as differences in extraction techniques (KUMAR; ROY, 2018).

Figure 1 – Total phenolic and flavonoid content of various extracts of C. officinalis.

DPPH radical scavenging assay

The antioxidant activity of C. officinalis extracts was determined using the DPPH radical scavenging assay and the FRAP method to assess their electron-donating capabilities. As shown in Figure 2, the methanol extract exhibited the strongest DPPH radical inhibition (78.71%), followed by the chloroform fraction (65.23%), with the hexane fraction showing the lowest inhibition (43.11%) at 500 µg/mL.

Figure 2 – DPPH radical scavenging activity of different solvent of C. officinalis.

These variations in activity are likely to be due to differences in the bioactive compound composition of the extracts. The high DPPH inhibition is attributed to polyphenolic compounds capable of neutralizing free radicals, suggesting potential therapeutic applications for oxidative stress-related conditions. This study’s findings align with Ismail’s research (ISMAIL, 2017), although they differ from previous reports indicating no significant DPPH activity for certain Corallina extracts (HSAINE et al., 2019).

Ferric reducing ability

The reducing capacity of phytochemicals extracted from C. officinalis is illustrated in Figure 3, which is contingent upon concentration. A statistically significant difference (p < 0.05) was noted between the reducing power of the methanol extract and the chloroform and hexane fractions. The ability to decrease, shown by the conversion of Fe2+ to Fe2+, serves as a crucial antioxidant defense mechanism that entails the transfer of electrons and hydrogen atoms (OBOH, 2008). The correlation between radical scavenging activity and total polyphenolic content supports the notion that polyphenolic compounds are the principal contributors to the antioxidant activities seen in these extracts.

Figure 3 – Total reducing power of all extracts of C. officinalis.

Conclusion

The methanolic extract of C. officinalis demonstrated the highest total phenolic content and antioxidant activity, whereas the hexane fractions revealed the lowest values. The strong correlation between phenolic component content and antioxidant capability indicates that solvent selection significantly affects the extraction of bioactive chemicals. The results of this study further substantiate that methanol serves as an efficient extraction solvent. Moreover, they illustrate the possibility for additional research into the pharmacological applications of C. officinalis, particularly for oxidative stress mitigation and the discovery of active constituents.

Conflicts of interest

The authors declare no conflicts of interest regarding the work presented here.

Authors’ contribution

Abdellatif Alioui – execution of the experiment, guidance, corrections and revision of the text; Benattouche Zouaoui – execution of the experiment; Asmaa Belmimoun – work corrections.

Financial support

We are grateful to Mascara University in Algeria.

Acknowledgements

We are grateful to Prof Hamdi Bendif for all support.

References

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ZUBIA, M.; THOMAS, O. P.; SOULET, S.; DEMOY-SCHNEIDER, M.; SAULNIER, D.; CONNAN, S.; MURPHY, E. C.; TINTILLIER, F.; STIGER-POUVREAU, V.; PETEK, S. Potential of tropical macroalgae from French Polynesia for biotechnological applications. Journal of Applied Phycology, v. 32, n. 4, p. 2343-2362, 2020. https://doi.org/10.1007/s10811-019-01920-8

Received on December 1, 2024

Returned for adjustments on June 6, 2025

Received with adjustments on August 3, 2025

Accepted on August 26, 2025

Agrarian Academic Journal

agrariacad.com

doi: 10.32406/v8n5/2025/12-23/agrariacad

Contribution to the study of the floristic diversity of steppe zone Tiaret (Algeria). Contribuição para o estudo da diversidade florística da zona estepária de Tiaret (Argélia).

Houria Ouzzir¹, Yasmine Kadi Hanifi²

^1- PhD student, Laboratory of Ecology and Environment, University of Science and Technology Houari Boumediene – USTHB, BP 32 Bab Ezzouar, 16111 – Algiers, Algeria. E-mail: houriabalegh6@gmail.com

^2- Professor, Laboratory of Ecology and Environment, University of Science and Technology Houari Boumediene – USTHB, BP 32 Bab Ezzouar, 16111 – Algiers, Algeria. E-mail: hykadihanifi@yahoo.fr

Abstract

This study is devoted to steppe zone of the Tiaret region. Our work consists in highlighting the floristic biodiversity following a flora inventory, using subjective sampling – the simplest and most intuitive form of sampling – in order to obtain a database in which taxonomic, ecological and other characteristics are specified, revealing the importance of this biodiversity. The results of the flora analysis study led to the identification of 159 taxa divided into 28 botanical families and encompassing 101 genera. Endemic vegetation includes 15 taxa. As regards rarity, there are 08 fairly rare species, 01 rare species and 04 very rare species. Examination of the biological types of all the vegetation surveyed revealed that therophytes, numbering 71, dominate the scene with 45%. The Mediterranean phytochoric element is predominant with 63 species. The high perturbation index (62%) reflects a high degree of disturbance to the vegetation in this zone, which also reflects a more open environment (anthropozoic pressure). We recommend to the sustainable use of biodiversity. through the implementation of several integrated strategies.

Keywords: Subjective sampling. Flora analysis. Anthropozoic pressure. Preservation of biodiversity.

Resumo

Este estudo é dedicado à zona de estepe da região de Tiaret. Nosso trabalho consiste em destacar a biodiversidade florística seguindo um inventário da flora, utilizando amostragem subjetiva – a forma mais simples e intuitiva de amostragem – a fim de obter um banco de dados no qual características taxonômicas, ecológicas e outras são especificadas, revelando a importância dessa biodiversidade. Os resultados do estudo de análise da flora levaram à identificação de 159 táxons, divididos em 28 famílias botânicas e abrangendo 101 gêneros. A vegetação endêmica inclui 15 táxons. Em relação à raridade, há 8 espécies bastante raras, 1 espécie rara e 4 espécies muito raras. O exame dos tipos biológicos de toda a vegetação pesquisada revelou que terófitas, totalizando 71, dominam a cena com 45%. O elemento fitocórico mediterrâneo é predominante, com 63 espécies. O alto índice de perturbação (62%) reflete um alto grau de perturbação da vegetação nesta zona, o que também reflete um ambiente mais aberto (pressão antropozoica). Recomendamos o uso sustentável da biodiversidade por meio da implementação de diversas estratégias integradas.

Palavras-chave: Amostragem subjetiva. Análise da flora. Pressão antropozoica. Preservação da biodiversidade.

Introduction

Diversity is the most striking characteristic of this life (TILMAN, 2000). The diversity of life forms, so numerous that we have yet to identify most of them, is the greatest wonder of this period (WILSON, 1988).

Biodiversity refers to the variety of living species that inhabit the biosphere. It is also the total richness or number of living species that inhabit a given type of habitat, the whole of an ecosystem, a biogeographical region or the entire biosphere (RAMADE, 2008).

According to the United Nations Convention on Biological Diversity, held in Rio de Janeiro in 1992 (CBD, 1992), biological diversity is defined as the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part.

It was in 1992, at the Earth Summit, that the action plans for sustainable development were defined, and it was on the same date that the Convention on Biological Diversity was opened for signature with a view to the sustainable use of its components and the fair and equitable sharing of the benefits arising out of the utilization of its genetic resources.

The Mediterranean basin is a biodiversity hot spot (MYERS et al., 2000), it is the second largest hot spot in the world and the largest of the five Mediterranean climate regions on the planet. It is also the third richest hot spot in the world in terms of plant diversity (MÉDAIL; MYERS, 2004).

Algeria’s overlapping geographical location between two floral empires gives it a highly diverse flora, with species belonging to different biogeographical elements. Floristic diversity is the most visible element of biodiversity (DAJOZ, 2008).

The Algerian flora comprises around 4,000 taxa divided into 131 botanical families and 917 genera, of which 464 taxa are national endemics (387 species, 53 subspecies and 24 varieties) (YAHI; BENHOUHOU, 2011).

The steppic zone occupies the southern part of the Wilaya; it corresponds to the high steppic plains that slope imperceptibly down towards Chott Chergui and the Oued Touil valley.

It covers an area of 1.380,401 ha, or 68.44% of the total area of the Wilaya Tiaret. For the most part, they are located in the average arid bioclimatic sub-stage which is characterized by purely steppe vegetation and varying rainfall between the 200 and 300 mm / year isohyets (PAWT, 2008) (FIGURE 1).

Figure 1 – Situation map of Tiaret’s area.

The most dominant type of training vegetation in the region is steppe with a surface area of 974.967,65 ha, followed by herbaceous crops with 150.322,90 ha, located to the north of the communes of Madna, Sidi Abderahamane, Chehaima, Ain Deheb, Naîma, Faidja and Rechaiga, and practically the whole of the commune of Medrissa; another part of this formation is located to the south of the wilaya in the communes of Zmalet Emir Abdelkader and K’sar Chellala.

The region’s steppe is degraded over an area of almost 438.224,98 ha and is marked by the presence of species indicative of this state of degradation, such as Atractylis serratuloides, Peganum harmala, Astragalus armatus, Noaea mucronata and Salsola vermiculata. The esparto steppe (Stipa tenacissima) covers an area of 214.388,54 ha, equivalent to 17%, while herbaceous crops account for only 149.727,33 ha, or 11.94% of the total (BNEDR, 2008).

This steppe formation is based on perennial grasses Macrochloa tenacissima, Lygeum spartum, Aristida pungens and perennial chamaephytes Artemisia herba-alba, Artemisia compestre, Helianthemum hirtum.

Its facies of degradation Noaea mucronata, Peganum harmala, Thymelaea microphylla, Arthrophytum scoparium, Astragalus armatus, Atractylis serratuloides.

This research initiative aims to invent and analyze the floristic composition, the distribution of species according to their ecological affinities, and the structure of the vegetation in this semi-arid environment. It also enables us to assess species richness, the predominance of certain biological groups (such as therophytes and chamephytes). At the same time exploring the interactions between humans, biodiversity and ecosystems while identifying sustainable solutions for their preservation, to measure the impact of disturbances on the vegetation. The study thus contributes to a better understanding of ecological dynamics and provides a basis for the conservation and sustainable management of this steppe biodiversity.

Material and methods

Vegetation surveys are carried out using traditional methods, by drawing up a list of all the plant species present on a previously determined surface unit within a homogeneous station; this is the minimum area (HAMMADA, 2007); in our case, it is 100m².

The sampling used is subjective the simplest and most intuitive form, which consists in selecting as samples areas that appear particularly homogeneous and representative in accordance with the stigmatist method, the surveys were carried out on areas that were homogeneous in terms of physiognomy, flora and ecology (GOUNOT, 1969)

The linear survey is considered as an effective way to study the evolution of the vegetation cover when it is a permanent line (GOUNOT, 1969; AIDOUD, 1983); 10 stations were sampled; 110 surveys were performed (TABLE 1).

The list of plant species can be easily identified by consulting a number of references:

– The flora of Algeria (QUEZEL; SANTA, 1962-1963);

– The flora of the Sahara (OZENDA, 1977);

– The Dobignard and Chatelain index (2010-2013);

– The website of the database of plants in Africa (CJBG, 2021);

– The new flora of Algeria and the southern desert regions (QUEZEL; SANTA, 1962-1963) supported by the website (tela-botanica).

 Table 1 – Distribution of surveys in the Tiaret steppe region.

Socio-economic aspects

Nearly half of the population working in the various sectors of these communes is livestock farmers, practicing traditional agriculture represented mainly by cereal growing, with yields too low to meet their needs, and extensive livestock rearing.

Results and discussion

1. Floristic study

1.1 Floristic composition

Floristic composition varies according to climatic conditions (mainly rainfall and temperature), type of exploitation, soil and topography (AIDOUD, 1989).

In all the stations studied, we recorded 159 species belonging to 28 families. It should be noted that of the 28 families recorded, 10 are represented by only one species. However, 04 families, respectively the Asteraceae (42 species), Poaceae (17 species), Fabaceae (15 species) and Amarantaceae (10 species), are the most dominant (FIGURE 2; TABLE 2).

Figure 2 – Specific distribution of the most common families in the study area.

Table 2 – Flora recorded (generic and specific) by 28 botanical families in the study area.

1.2. The biological spectrum

Biological types are a combination of morphological characteristics resulting from the adaptation of species to environmental conditions (RAUNKIAER, 1934; BRAUN-BLANQUET, 1951; PIGNATTI, 1982; SIRVENT, 2020), especially during unfavorable periods.

As in most studies of steppe environments, therophytes are dominant, which is a particular feature of arid and semi-arid zones (FLORET; PONTANIER, 1982; LE HOUÉROU, 1986 and 1995). The dominance of species which complete their cycle in less than a year is only the consequence of various hazards combining climate and pressure on resources (AIDOUD; TOUFFET, 1996; BOUCHAREB, 2012).

Kadi Hanifi (2003) confirmed that the regression of steppe formations generally results in the chamaephytisation of thorny species of no economic interest, which are abandoned and pushed aside by the livestock.

The distribution of the species in the study according to biological type is shown in Figure 3.

Figure 3 – Species distribution by biological type.

In our station, the Theophytes are the most represented (45%) of the total inventoried before the Chamephytes (25%), the Hemicryptophytes (17%) and apart respectively Geophyte (05%) and Phanerophytes (04%).

The abundance of therophytes is related to the aridity of the environment (NEGADI et al. 2014). Chamephytisation is also closely linked to the degradation of the environment by human activity, with the proliferation of hardy species.

1.3. The phytogeographical spectrum

According to Quezel (1983), the biogeographical diversity of Africa is due to the various climatic changes it has undergone since the Miocene, which have led to the migration of tropical flora.

Figure 4 – Distribution of species by chorological type.

The analysis of the overall phytochoristic spectrum reveals the predominance of the Mediterranean element, with a high rate of 40%, i.e. 63 species, followed by the Southern element (13%), Southern-Mediterranean (11%) and Nordic (08.5%). Mediterranean-Septentrional (08%). As for the other elements, they contribute little to floristic richness. Iso-latitudinal-Mediterranean (04.5%), Atlantic (04%), Cosmopolitan (03.5%) (FIGURE 4).

1.4. Endemism and rarity

We note that the highest proportion of species are North African (66,66%), followed by Algerian (20%). The endemic Algerian-Moroccan (06,66%) and Saharan (06,66%) species are poorly represented (TABLE 3).

Table 3 – endemic species to the study area.

Two non-endemic taxa present in our study area are protected at national level by executive Decree No. 12-03 of 04 January 2012 establishing the list of protected non-cultivated plant species in Algeria. These are Hélianthemum Lippii (L.) Pers. (Cistaceae) and Ononis natrix L. (Fabaceae).

The distribution of taxa by degree of rarity is as follows: 08 taxa fairly rare; 01 taxa rares; 04 taxa very rare (TABLE 4):

Table 4 – Rare species in the study area.

AR: fairly rare; R: rare; RR: very rare.

1.5. Disturbance index (LOISEL; GOMILA, 1993)

IP = 62%, shows that the richness of therophytes and Chamephytes in the study area indicates a high degree of disturbance, which also reflects a more open environment. It also reveals a degradation of the plant cover due to human activity.

Discussion

The 110 surveys carried out enabled 159 species belonging to 101 genera and 28 botanical families to be recorded and identified. The biological types show a predominance of therophytes (71 species). In the Mediterranean as a whole, the Mediterranean phytochoric element is predominant with 63 species. Endemics are represented by 15 species. Rare species in the study area are 13 species.

The biological types of flora recorded for our study area can be summarised as follows: Th > Ch > He > Ge > Ph.

Plant regression is evidenced by the high number of therophytes (45%), as well as a sharp increase in thorny and toxic species (Astragalu, Atractylis serratuloides, Carthamus lanatus, Thymelaea microphylla, Noaea mucronata, Onopordun arenarium, Thapsia garganica, Euphorbia and Peganum harmala) and a few psammophilous species (Stipagrostis pungens, Filago spathulata, Helianthemum lippii) to the detriment of palatable species, especially those of the Fabaceae and Poaceae families:

– The therophytization observed in our area is linked to the harshness of the climate and to anthropogenic actions that are increasingly degrading the conditions for the installation of new species. Emberger (1955) claim that the rate of therophytes increases with the aridity of the medium. This wealth is due to the process of ”biological recovery” of the reconstitution, regeneration and reappearance of species threatened with destruction by degradation factors.

– As our area is agro-pastoral, we found that the most palatable species (Asteriscus pygmeus, Astragalus mareoticus, Astragalus sinaicus, Hippocrepis multiciliquosa, Atractylis cancellata, Cutandia dichotoma, Evax pygmea, Malva aegyptiaca, Medicago laciniata, Medicago minima, Muricaria prostrata, Nonnea micrantha, Plantago albicans, Stipa and Vicia monantha subsp cinerea) are becoming rarer.

– On the other hand, unpalatable species such as Atractylis serratuloides, Noaea mucronata and Thymelaea microphylla are increasingly colonising rangelands used for summer and autumn grazing.

– Most of the species on the list of flora in undeveloped rangelands compiled by HCDS, DGF…. are poor species, such as: Atractylis humilis, Noaea mucronate, Echinops spinosus, Thapsia garganica, Peganum harmala.

– Grazing also favors the chamephytes repelled by herds such as Thymelaea microphylla and Astragalus armatus.

The high disturbance index (62%) in this study influences plant composition, favoring species adapted to environmental and anthropogenic stress, the main impacts observed are as follows:

– Dominance of therophytes and chamephytes, typically, this dominance is due to overgrazed environments. overgrazing reduces the biomass of perennial species such as Stipa tenacissima and favours thorny and toxic plants (MEKIDECHE et al., 2018).

– Impoverishment of biodiversity: anthropogenic disturbances lead to a reduction in endemic and Mediterranean species replaced by multi-regional or ubiquitous taxa (BENKHETTOU et al., 2015).

Soil degradation and limited resilience increased erosion due to reduced perennial plant cover effects:

– Water retention: limiting the growth of deep-rooted species.

– Soil fertility: favoring species tolerant of impoverished soils (TRÉMOLIÈRES et al., 2008).

Impacts on ecosystem services: the dominance of ruderal species reduces:

– Fodder productivity, crucial for local livestock

– Farming Carbon sequestration capacity, linked to the limited above-ground and root biomass of therophytes.

The high disturbance index reflects a profound transformation of steppe ecosystems, marked by forced adaptation of the flora to human and climatic pressures, while weakening natural resilience mechanisms (BENKHETTOU et al., 2015).

Recommendations

To better preserve floral biodiversity in the semi-arid steppe region of Tiaret, several integrated strategies can be implemented, drawing on lessons learned from local studies and international best practice:

Sustainable land management and ecological restoration. Adopting appropriate agro-pastoral techniques, such as rotational grazing and regulating overgrazing, would reduce pressure on key species (Stipa tenacissima, Artemisia herba-alba). The reintroduction of native species through targeted reforestation programs would strengthen ecosystem resilience. Combating soil erosion by mechanical means (benching) or biological means (stabilizing vegetation) is also crucial (DGF/GEF/PNUD-ALG/00/G35/2005, 2014).

Involving local communities. Developing economic alternatives (crafts based on aromatic plants, ecotourism centered on steppe landscapes) would reduce dependence on natural resources. Training in sustainable agriculture and water management could improve farming practices while preserving the flora. The example of the GEF project in Algeria shows that the involvement of local NGOs (Association de Protection de la Steppe de Mecheria) increases the effectiveness of measures (DGF/GEF/PNUD-ALG/00/G35/2005, 2014).

Strengthening protected areas. Extending and connecting existing protected areas with ecological corridors would encourage genetic exchange between plant populations. The implementation of adaptive management plans, incorporating regular monitoring of floristic diversity (Shannon-Weaver index, disturbance rate), would enable strategies to be adjusted.

Institutional framework and international cooperation. Harmonizing agricultural, forestry and conservation policies would avoid contradictions between development and preservation. Programs such as those of the GEF (Global Environment Facility) have demonstrated the importance of international funding to support local initiatives (DGF/GEF/PNUD-ALG/00/G35/2005, 2014).

Research and monitoring. A strengthening of long-term phyto-ecological studies, coupled with satellite monitoring systems, would provide a better understanding of the climatic and anthropogenic dynamics affecting the region. The creation of a digitized regional herbarium would facilitate the monitoring of endangered species (DGF/GEF/PNUD-ALG/00/G35/2005, 2014).

The sustainable use of biodiversity and preserving plant biodiversity: a global challenge. Every year, a large number of plant species disappear without new ones being born. This impoverishment of species is due to a number of factors, including natural factors (climatic aridity, silting up), not forgetting anthropogenic factors (overexploitation of natural resources, overgrazing and overcrowding, modification of landscapes and land use, intensive agriculture, pollution.

If human activities are the immediate causes of the erosion of biological diversity, the solutions and remedies must be sought in the behavior of societies.

In other words, the conservation of biodiversity depends on the development choices made at both national and international level.

Conclusion

Based on field work and data processing, the steppe region of Tiaret presents a rich diversity of flora, but is exposed to disturbance, with vegetation dominated by species adapted to semi-arid Mediterranean conditions.

The results of the flora analysis yielded 159 taxa divided into 28 botanical families and encompassing 101 genera. Endemic vegetation includes 15 taxa. As regards rarity, there are 08 fairly rare species, 01 rare species and 04 very rare species. Examination of the biological types of all the vegetation surveyed revealed that therophytes, numbering 71, dominate the scene with 45%. The remaining types are respectively: chamaephytes, hemicryptophytes, geophytes and phanerophytes. Examination of the phytochoric types of all the vegetation surveyed revealed that the Mediterranean element dominates over the other types of presents.

Anthropogenic pressure on environments through overgrazing generates not only the loss of global and endemic floral biodiversity but also the proliferation of toxic and non-pastoral plants.

For sustainable development and effective protection of the existing flora, action must focus on preserving the environment and on the socio-economic aspect by involving the local population.

These combined actions (limit overgrazing, protecting soils, restore natural habitats, setting up protected areas or nature reserves, raising people’s awareness) integrated into a national policy of conservation and sustainable management, will reduce the pressure on this fragile ecosystem and ensure its long-term survival.

These results show that steppe development projects and the introduction of forage species are effective solutions for combating silting and restoring degraded rangelands.

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Received on November 29, 2024

Returned for adjustments on May 26, 2025

Received with adjustments on June 18, 2025

Accepted on August 2, 2025