Floristic composition, biological spectrum, and phytogeographic distribution of the Bin Dara Dir, in the western boundary of Pakistan

Manan, Fazal; Khan, Shujaul Mulk; Muhammad, Zahir; Ahmad, Zeeshan; Abdullah, Abdullah; Rahman, Amjad ur; Han, Heesup; Ariza-Montes, Antonio; Contreras-Barraza, Nicolás; Raposo, António

doi:10.3389/ffgc.2022.1019139

ORIGINAL RESEARCH article

Front. For. Glob. Change, 16 November 2022

Sec. Forest Management

Volume 5 - 2022 | https://doi.org/10.3389/ffgc.2022.1019139

This article is part of the Research Topic Mountainous Forest Ecosystems: Challenges and Management Implications View all 16 articles

Floristic composition, biological spectrum, and phytogeographic distribution of the Bin Dara Dir, in the western boundary of Pakistan

$\nFazal Manan$ Fazal Manan¹

Shujaul Mulk Khan¹^*

Zahir Muhammad²

Zeeshan Ahmad¹

Abdullah Abdullah¹

Amjad ur Rahman¹

Heesup Han³^*

Antonio Ariza-Montes⁴

Nicolás Contreras-Barraza⁵

António Raposo⁶

¹Department of Plant Sciences, Quaid-i-Azam University Islamabad, Islamabad, Pakistan
²Department of Botany, University of Peshawar, Peshawar, Pakistan
³College of Hospitality and Tourism Management, Sejong University, Seoul, South Korea
⁴Social Matters Research Group, Universidad Loyola Andalucía, Córdoba, Spain
⁵Facultad de Economía y Negocios, Universidad Andres Bello, Santiago, Chile
⁶CBIOS (Research Center for Biosciences and Health Technologies), Universidade Lusófona de Humanidades e Tecnologias, Lisboa, Portugal

This study assessed the floristic composition, biological spectrum, and phytogeographical elements of the Bin Dara western boundary of Pakistan. The flora consisted of 140 plant species belonging to 47 families. The most dominant family was Poaceae (with 14 species), followed by Asteraceae (11 species). The biological spectrum showed the therophytes (71 species, 50.71%) as the dominant life form class, followed by mega-phanerophytes (27 species, 19.28%), nano-phanerophytes (15 species, 10.71%), geophytes (10 species, 7.14%), chamaephytes (9 species, 6.42%), and hemi-cryptophytes (8 species, 5.71%). Leaf size classes comprised of nanophylls (48 species, 34.28%), microphylls (32 species, 22.85%), mesophylls (22 species, 15.71%), macrophylls (17 species, 12.14%), leptophylls (12 species, 8.57), megaphylls (8 species, 5.75%), and aphyllous (1 species, 0.71%). Cosmopolitan was the most prominent form of phytogeographic elements (with 17 species, 12.14%), followed by pantropical and Euro-Siberian Mediterranean Irano-Turanian (14 species, 10%) each. The pluriregional represented (13 species, 9.28%), Holarctic and Mediterranean Irano-Turanian (10 species, 7.14%), Irano-Turanian and Western Himalayan (9 species, 6.42%) each. It is recommended that further study is needed to map the vegetation, its indicators, and rare species that face a huge threat of endangerment.

Introduction

The floristic composition of any area gives us essential information about different plant species diversity and their distribution (Ali et al., 2018; Bano et al., 2018; Gul et al., 2018). It leads to the proper identification of plant species and thereby conservation in a scientific and systematic way. The distribution of plant species is a valuable source of information for environmental factors and ecosystem services in a particular habitat (Angyalossy et al., 2022; Flores-Argüelles et al., 2022; Magray et al., 2022; Shannon et al., 2022; Wani et al., 2022b; Watts et al., 2022). Floristic diversity is used to interpret plant species of any geographical area, whether cultivated or wild in their nature (Farooq et al., 2019; Khan and Badshah, 2019; Ca et al., 2020; Wani and Pant, 2021; Wani et al., 2022a). The presence of all plant species found in a particular area is termed flora while vegetation is related to the relative importance of plant species, their life and leaf form, population, and distribution in relation to space and time. Floristic inventory can help us to understand the features of vegetation characteristics (Mehmood et al., 2015, 2017; Rahman et al., 2016; Li et al., 2021; Zhao et al., 2021) and it is important for human existence, economic health, ecosystem function, and stability (Khan et al., 2016; Wani et al., 2021; Su et al., 2022; Wani and Pant, 2022).

The biological spectrum of an area also gives the climate picture of that region. It tells about weather patterns, especially the rainfall and temperature phenomena, and their distribution over the year. Climatic conditions over a longer period give rise to phytogeographic consistency among the floristic elements. According to Takhtajan (1969a) and Ali and Qaiser (1986), there are three phytogeographical regions in Pakistan i.e., Irano-Turanian, Saharo-Sindian, and the Indian regions (Khan et al., 2020). But Kitamura (1960) and Hara (1966) also recognized the Sino-Japanese region. Thus, four phytogeographical regions are recognized in Pakistan. Each region is delimited based on certain criteria, apart from others, by Zohary (1950), and characterized by the presence of a component of the flora or phytogeographical elements.

In the Irano-Turanian Region, there are both diurnal and annual plant species characterized by extreme temperature and low precipitation. There is a considerable difference of opinion so far as the subdivision of the region is concerned. Two sub-regions, i.e. Western and Eastern Irano-Turanian sub-regions were recognized because of the climatic and physiognomic factors (Zohary, 1950). The Eastern Irano-Turanian sub-region occurs at 35°-36° north latitude and the Western Irano-Turanian sub-region is at 29°-30° north latitude. The western Himalayas are situated in the Western Irano-Turanian subregion, which has many endemic plant species. The western boundaries of the Sino-Japanese region in the Himalayas touch western Nepal (Takhtajan, 1969b) and according to the findings of Zohary (1950), Kitamura (1960), and Hara (1966) it further spreads through Pakistan into Afghanistan to their western limit. This is supported by the interruption of the maximum rainfall (180 cm) areas (Haq et al., 2020). Before glaciation, the present Sino-Japanese flora had changed relatively little from the vegetation of the north-temperate regions that surrounded the whole northern hemisphere (Axelrod and Raven, 1978). While the name “Saharo-Sindian” was given by Eig (1931), the area spreads from the Atlantic coast of north Africa through the Sinai Peninsula, the entire Sahara, most of Arabia, more than half of Palestine, part of Syria, south Iran, south Iraq, southern Baluchistan, Sindh, most parts of Punjab in Pakistan and the Rajasthan desert in India (Eig, 1931).

The Indian region comprises the flanks of the Himalayas, the Gangetic plain, the Indian peninsula proper, and Sri Lanka. The territory of this region is not continuous in Pakistan. It lies between 27° and 28° north latitude in the southeastern part and between 29° and 32° north latitude in the eastern Punjab province. Distribution of phytogeographic elements helps in tracing plant migration, origination, evaluation, plant speciation, distribution range, conservation plans, perception of ecological nature, diversification, and plant wealth.

However, very little attention has been given to the assessment of phytogeographic elemental distribution patterns in these areas. Therefore, the present study was conducted to find out the floristic composition, biological spectrum, and phytogeographic distribution of the Bin Dara, in the western boundary of Pakistan. The results might be helpful to ecologists, plant geographers, conservationists, and ethnobotanists in understanding the vegetation structure, conservation status, and characteristics in the region. The procedure adopted in the current study can be followed for the assessment of phytogeographic elements of any ecosystem of the world.

Materials and methods

Study area

The Bin Dara lies at 35°5′ 23.82″ to 35°6′ 1.41″ N latitude and 71°40′ 48.28″ to 71°41′ 52.66″ E longitude with an elevation range of 1,553–2,764 m in the western Himalaya floristic region in Pakistan (Figure 1). It has rigid topography, dominated by hills with hard rocks. Its temperature remains moderate and warm in the summer season. June and July are the hot months of the year (Manan et al., 2020). The area's mean annual minimum and maximum temperatures are 10 and 27°C, respectively.

FIGURE 1

Figure 1. Map showing Bin Dara, western boundary of Pakistan.

The current study was conducted through the detailed methodology as follows.

Field survey

Regular field surveys were conducted throughout Bin Dara, Dir, using standard ecological techniques (Ahmad et al., 2016; Amri et al., 2019; Mumshad et al., 2021; Ur Rahman et al., 2021; Ali et al., 2022). We followed the standard taxonomic procedures for collecting, drying, and further processing the herbarium specimens (Bridson and Forman, 1998). Plant specimens were collected, labeled, placed in blotting papers, pressed with a plant presser, and poisoned using mercuric chloride plus ethyl alcohol solution. Specimens were then fixed on the standard herbarium sheets, having a size of 17.5″ × 11.5″. All the plant species were identified with the help of “Flora of Pakistan” and other available literature (Nasir and Ali, 1972). Complete floristic lists of species along with ecological descriptions were prepared for further analyses.

Life form classification

All recorded plant species were classified into different life form classes using the Raunkiaer (1934) method. Its detailed descriptions are as follows:

Phanerophytes (Ph)

Plants with perennating buds emerging at least 25 cm above the ground surface are called Phanerophytes. Based on height, Phanerophytes are further divided into the following subclasses.

Megaphanerophytes: (Mg). > 30 m.

Mesophanerophytes: (Ms). 7.6–30 m.

Microphanerophytes: (Mp). 2–7.5 m.

Nanophanerophytes: (N). 0.25–2 m.

Chamaephytes (Ch)

These are perennial plants in which their shoots or buds lie up to 25 cm on an upright stem from the ground. Chamaephytes are also called surface plants. They are characteristically found in cool and dry climates.

Hemicryptophytes (He)

These are plants whose perennial buds lie near the ground where they are covered by soil and litter. Such plants are found in cold and moist climates. They include a multitude of grasses and forbs.

Geophytes/cryptophytes (G/Cr)

The plant's perennial buds lie beneath the ground level or underwater (hydrophytes). The underground reproductive parts (rhizome, corn, bulb, and tuber) are drying and freezing.

Therophytes (Th)

These plants survive unfavorable conditions in the form of seeds. They are annual herbs and usually grow in the rainy season only from seeds. Therophytes are typically found in desert grasslands.

Climbers and Liana

These plants use rocks, manmade structures, and other plants for their support and growth. Liana is a woody climber that is generally rooted in soil, but its leaves are often in full sun. They are often many meters from the ground.

\begin{array}{l} Raunkiar Biological Spectrum = \\ \frac{No . of individual of a species of a particular life form class}{Total No . of all species in a single strand} \times 100 \end{array}

Leaf size spectra

The leaf size spectrum gives the idea of the adaptations and physiology of plant leaves. Plants are classified into different leaf size spectra using Raunkiaer (1934) method. Detailed leaf size classes descriptions are as follows:

Leptophyll (L): 25 sq. mm

Nanophyll (N): 9 × 25 sq. mm

Microphyll (Mic): 9² × 25 sq. mm

Mesophyll (Mes): 9³ × 25 sq. mm

Macrophyll (Mac): 9⁴ × 25 sq. mm

Megaphyll (Ma): Larger than class Macrophyll.

\begin{array}{l} Raunkiar leaf size spectrum = n o n u m b e r \\ \frac{No . of individual of a species of a particular leaf size class}{Total No . of all species for that strand} \times 100 \end{array}

Floristic elements classification

Vegetation of the study area is described and classified into various floristic elements based on Brummitt et al. (2001) as defined in Table 1.

TABLE 1

Table 1. A description of the floristic elements in Bin Dara, Pakistan.

Results

Plant species composition

A total of 140 plant species were recorded belonging to 50 families. Out of which 46 families were Dicotyledons, two families Monocotyledons, and one family of Gymnosperm and Pteridophyte each. The most dominant family was Poaceae (with 14 species) followed by Asteraceae (11 species) and Lamiaceae (10 species). Regarding the habitat of the plant species, 101 were herbs, 12 were shrubs and 27 were trees (Figure 2).

FIGURE 2

Figure 2. Percentage-wise representation of the plant's habitat in Bin Dara, the western boundary of Pakistan.

Raunkiaer life form classification

Based on the Raunkiaer life form system of classification, Therophytes were the dominant plant species along with 71 members (50.71% of the total vegetation), followed by Megaphanerophytes (27 species, 19.28%), Nanophanerophytes (15 species, 10.71%), Geophytes (10 species, 7.14%), Chamaephytes (9 species, 6.42%) and Hemicryptophytes (8 species and 5.71%) (Table 2).

TABLE 2

Table 2. Life form spectra of the Bin Dara vegetation.

Raunkiaer life size classification

The leaf size of the region was dominated by Nanophylls containing a total of 48 species (34.28%), followed by Microphyllous with 32 species (22.85%), Mesophylls with 22 species (15.71%), Macrophylls with 17 species (12.14%), and Leptophylls with 12 species (8.57%). Furthermore, Megaphylls with 8 species (5.75%), and Aphyllous with 1 species (0.71%) were the least concentrated in the area (Table 3, Figure 3).

TABLE 3

Table 3. Life form spectra of the Bin Dara, Dir, vegetation.

FIGURE 3

Figure 3. Leaf size spectrum in Bin Dara, western boundary of Pakistan.

Phytogeographic/floristic elements

The vegetation of the present study recognized 27 different floristic elements. Cosmopolitan (12.14%) was the highest percentage of elements, followed by Pantropical and Euro Siberian-Mediterranean-Irano-Turanian (ES-M-IT) with 10% each. The Pluriregional (PL) represents 9.28%, holarctic and Mediterranean- Irano-Turanian (7.14%), IT and WH 6.42% each (Figure 4). The other elements were less represented in the study area. Six species (4.28%) were endemic or nearly endemic to the western Himalayan region. These endemic species were Parrotiopsis jacquemontiana, Cedrus deodra, Pinus wallichiana, Quercus baloot, Viburnum cotinifolium, and Bistorta amplexicaulis (Table 4).

FIGURE 4

Figure 4. Floristic elements in Bin Dara, western boundary of Pakistan.

TABLE 4

Table 4. Life form, geographical distribution, leaf size, and floristic elements of the Bin Dara, in the western boundary of Pakistan.

Discussion

Ecological sampling and analyses are of prime importance for the vegetation of any geographic zone. Its precise interpretation can help in successfully achieving this aim. Many such sampling-based studies frequently interpret the vegetation at habitats, ecosystems, and regional and global levels (Khan et al., 2011; Longo et al., 2019; Abbas et al., 2021; Ahmad et al., 2022b; Anwar et al., 2022; Haq et al., 2022; Munyasya et al., 2022; Rasheed et al., 2022; Yang et al., 2022). Such studies interpret the intricate vegetation structure more meaningfully in relation to the abiotic environment (Khan et al., 2017; Miao et al., 2018; Ahmad et al., 2021, 2022a; Iqbal et al., 2021; Ali et al., 2022a,b; Hussain et al., 2022; Khan S. A. et al., 2022). The present study revealed that the dried condition of the Bin Dara, Dir, is reflected in its vegetation in the form of stunted growth, small leaf size, sparse distribution, dwarf height, and isolated individuals of plant species that in turn are characteristics of the xerophytic flora. Our findings are also supported by some of the studies from adjacent areas (Abbas et al., 2019; Ahmad et al., 2019; Ahmed et al., 2019; Anwar et al., 2019; Hussain et al., 2019; Kamran et al., 2020; Khan, 2022). Furthermore, biological spectra are used to assess the life form and leaf sizes for better interpretations of the climatic conditions of an ecosystem. These physiognomic characteristics are considered indicators of biotic interaction, and climatic and habitat deterioration. A similar biological spectrum of different areas shows similar climatic conditions. According to Raunkiaer (1934), the climate and habitat of an area are characterized by the life form and biological spectrum of an area, though, the proportion of life forms can be altered due to biological disturbances.

The overall vegetation of the study region is dominated by therophytes with 71 species (50.71%) followed by megaphanerophytes with 27 species (19.28%). The dominance of therophytes shows that the study area is under huge anthropogenic and biotic pressure like grazing pressure and human disturbance (Ullah and Badshah, 2017; Manan et al., 2020; Bedair et al., 2021). Hence, as a result, hemicryptophytes cannot survive in such type of environment. Our results are similar to the finding of Al-Yemeni and Sher (Al-Yemeni and Sher, 2010), who reported that therophytes are a dominant life form spectra due to different environmental gradients in the Asir Mountain, Saudi Arabia. In addition, similar studies being carried out in the adjacent area like Sher and Khan (2007), Khan et al. (2013), Sharma et al. (2014), and Hussain et al. (2015) reported that therophytes, along with hemicryptophytes and megaphanerophytes, are the dominant vegetation in their respective regions.

The leaf size spectrum identified nanophyll and microphyll as the dominant leaf size spectra in the current project area. Similarly, Nasir and Sultan (2002) reported Nanophylls as the dominant life form from the Botanical Garden at Azakhel, District Nowshera, Pakistan. Whereas Hussain et al. (2014) studied the flora of Sarsawa Hills, District Kotli in Azad Kashmir. They stated that Leptophylls, Nanophylls, and Microphylls were the dominant classes. Microphylls are characteristic of steppes, while Nanophylls are characteristic of hot deserts (Tareen and Qadir, 1993; Badshah et al., 2013). Large leaf species occur in warm moist climates while smaller leaves are characteristic of dry and cold climates and degraded habitats.

In the present study, the dominance of cosmopolitan elements can be attributed to dispersal mechanisms and geological activities in the past. These species are distributed on almost all continents (having worldwide distribution). The flora of the western Himalayan province is transitional between the eastern Asiatic and ancient Mediterranean (Takhtajan, 1986; Khan et al., 2020; Zeb et al., 2021; Khan S. M. et al., 2022). Bin Dara, being part of the western Himalayas, receives the monsoon rains during summer and heavy snowfall in winter; the plants renew growth at the approach of spring in the months of March–April (Manan et al., 2020). Ullah et al. (2015) also reported the dominance of Cosmopolitan, Pantropical, Euro-Siberian, Mediterranean, Irano-Turanian, and Pluriregion elements in Myankaleh Wildlife Refuge, Mazandaran Province, Iran. Siadati et al. (2010) also found the dominance of Euro-Siberian and Pluriregion elements in Hyrcanian forests in northern Iran. Some of the unique floristic elements in the study region might be due to the collision of Eurasian and Indian tectonic plates. Further studies are recommended to study the edapho-physiological pattern of the area to understand the underlying mechanisms of the present-day vegetation for its future management and conservation purposes. This study also covers the three sustainable development goals including life on land, climate action, good and wellbeing (Ejaz et al., 2022; Shehzadi et al., 2022).

Conclusion

Therophytes and nanophylls are the dominant life form and leaf form spectra of the Bin Dara, Dir, in the western boundary of Pakistan. Cosmopolitan, pantropical, Euro-Siberian, Mediterranean, Irano-Turanian, and pluriregion were the dominating phytogeographic elements in the studied region. The dominance of therophytes indicates that the study area is under immense anthropogenic pressure and an accelerated rate of deforestation. It is therefore recommended that the eastern and western Himalayan regions should be given more focus on the proper management and conservation of vegetation in the current scenario of climate change in the studied mountainous regions. It is also recommended that the methodology adopted in the current study can be followed to assess the phytogeographic elements of any habitat in the world.

Data availability statement

The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author.

Author contributions

This work was conducted and written jointly by FM, SK, ZM, ZA, AA, AuR, and AR. Funding acquisition: HH, AA-M, and NC-B. Project administration: HH. Writing—review and editing: AA-M and NC-B. All authors have read and agreed to the published version of the manuscript.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Publisher's note

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References

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