Floristic composition , biological spectrum and phenological pattern of vegetation in the subtropical forest of Kotli District , AJK , Pakistan

A comprehensive floristic survey of Kotli District, Azad Jammu and Kashmir was conducted during 2014-2016 to analyse phytodiversity and ecological characteristics of plant resources. The flora comprised of 202 plant species distributed among 71 families and 176 genera. Of these, 6 species were pteridophytes, 1 species was a gymnosperm, 159 species were dicotyledons and 36 species were monocotyledons. Based on species numbers, Asteraceae (23 Spp), Poaceae (20 Spp), Fabaceae (15 Spp), Labiatae (11 Spp), and Euphorbiaceae (07 Spp) were the leading families. Based on biological spectrum, therophytes (73 Spp., 36.14 %) were dominant followed by hemicryptophytes (19.31%), nanophanerophytes (13.37%), geophytes (10.40%), lianas (7.92%), chamaephytes (7.43%) and megaphanerophytes (5.45%). Nanophylls (36.14%), leptophylls (26.73%) and microphylls (26.24%) were the major leaf size classes. Phenological study revealed four different flowering seasons, with April the peak flowering month during which 122 species blossomed. This current study will provide essential baseline information for ecologists, taxonomists and conservationists to carry out more detailed ecological investigations and conservation management planning for the plant resources of this area.


Introduction
The diversity and ecological characteristics of the plants of a particular area depend upon environmental conditions, including altitude and climate.Thus ecological characteristics, such as life form, leaf spectra and phenological pattern, can be used as indicators of prevailing environmental conditions [1].Flora refers to all plant life occurring in any particular geographic region at a specific geological period and includes the number of species.In contrast vegetation refers to the number and distribution of individuals of different plant species in a particular ecosystem [2].The study of floristic composition is a common taxonomic practice as it provides the baseline information for subsequent, more detailed ecological investigation as well as planning for conservation and sustainable management of the resources of the area [1,3].The concept of life form was first introduced by Humboldt with the term Vegetative Form.It ranked next to floristic composition in ecological studies [4] and is the outcome of the adaptation of plants to certain climatic conditions [5].The life form of a plant reflects the climate of the area and is also useful in comparing the geographical distribution of plant communities.Traditionally it was used in the description of vegetation structure at the community level [6].The most compact and consistent classification of life form is that of Raunkiaer, which is based on the degree of presence and protection of perenating buds.On the basis of life form, he recognized three different phytoclimates on earth including the therophytic climate in deserts, hemicryptophytic in the temperate zone and phanerophytic in the tropics.Mueller-Dumbois and Ellenberg [7] divided plant species in to five main life form categories based on similarity in their structure and function.Similarly leaf size classes have been used in vegetation description and in order to understand the physiological processes of plants and plant communities [8].Phenology refers to the study of the timing and causes of repeated biological phenomena with respect to the non-living and living factors and the relationship between the phases of different or the same species [9,10].Small variations in climate can have a great effect on the vegetation [11].For example, vegetation can be characterized by different patterns of climate-induced phenological events [12], with flowering induced by significant rain in the months of winter and summer, temperature differences, changes in photoperiodism, and drought [13].In addition to characterizing the vegetation, such studies can also be useful in developing effective management strategies as well as better understanding community level interactions and the vegetation regeneration potential [14].Some previous evaluation studies have been carried out on the floristic composition and ecological characteristics and phenological patterns of the vegetation of the more remote regions of Pakistan, including Azad Kashmir [1, 3, 15-23].However, the inaccessibility of the Kotli District means that this area has received very little exploration by plant taxonomists and ecologists, with only a very few published studies [23][24][25][26][27][28].Therefore, the present work was conducted in order to report on this areas floristic diversity and its ecological characteristics in order to provide the baseline information for subsequent more detailed ecological investigations and to provide the basis for conservation management of the natural resources of the area.

Study area, vegetation and climate
Kotli is one of the biodiversity rich areas of Azad Jammu and Kashmir.The district is located 130 km north of Islamabad, the capital of Pakistan (73°.47.180´ E to 74° 04.613´ E longitude; 33° 23.069´N to 33° 29.344´ N latitude; altitudinal range 450 m to 1900 m). Figure 1 shows the location of the various sampling sites used in this study.The region is mountainous and covers an area of 1860 km 2 .Climatically the area is dry subtropical at the lower altitudes and subtropical humid in the upper reaches with a mean annual precipitation of 1250 mm.

Floristic list, life form and leaf spectra
A complete list of plant species was prepared by alphabetical arrangement of the plant families and then in each plant family different plant species were arranged alphabetically.Plants were classified in to different life form and leaf size classes following Raunkiaer (1934), Hussain (1989)

Florisic composition Florisic composition
The flora of District Kotli consisted of 202 species of 71 families and 176 genera (Table 1).Of these, there were 159 species of dicotyledons, 36 species of monocotyledons, one species of gymnosperm and six species of pteridophytes.Pinus roxburghii was the only gymnosperm present in the investigated area.On the basis of growth form, 11 trees, 28 shrubs and 163 herbs comprised the 5.45%, 13.86% and 80.69% of the floral diversity of the investigated area (Table 2, Figure 2).
Asteraceae (23 Spp.) and Poaceae (20 Spp.) were the dominant families followed by Fabaceae (15 Spp.), Labiatae (11 Spp.), and Euphorbiaceae (7 Spp.).Acanthaceae, Amaranthaceae, Apiaceae, Cyperaceae, Malvaceae and Rosaceae had 5 species each.Boraginaceae, Convolvulaceae, Geraniaceae, Polygonaceae, Pteridaceae and Rananculaceae had 4 species each (Table 3, Figure 3).Each of the Apocynaceae, Brassicaceae, Caryophyllaceae, Primulaceae and Solanaceae had 3 species.The remaining 49 families had two or fewer species (Table 3).  4 Figure 4).The percentage of therophytes was high during spring as compared to monsoon season.5).5, Figure 7).Peak flowering in trees, shrubs and herbs occurred during April, while among the grasses flowering was at a peak during August.Ferns for the most part reproduced during June-August.Many species have been floristically listed from District Kolti, however most of them have a limited distribution on a quantitative basis due to their restricted life cycle.High species number is the indication of high species diversity and richness in the area.Qualitative features like floristic composition alone cannot provide the true picture of subtropical zone of Kotli district therefore the quantitative parameters and ecological behavior of vegetation resources like habit, phenology, life from and leaf spectra and ethno ecological potential should also be studied for a full description of the plant resources of this area.

Life form
The biological spectrum of the vegetation can be developed by classifying all the species of higher plants in to life form classes and expressing their ratio both in numbers as well as percentages.The biological spectrum provides an indication of the existing climatic condition and can be helpful in comparing widely separated geographical communities.However the proportion of various life forms within the biological spectrum may be changed due to biotic influences such as deforestation, overgrazing, agricultural practices and trampling etc [3, 23, 41].In the investigated area, the peak time for flowering was April-September.Less flowering was observed from November to February.Kakim and Yadava [60] similarly reported that in the sub-tropical forests of Manipur India flowering occurred during the months of April to September, while Jadeja and Nakkar [11] reported that in Gujrat India maximum flowering occurred in the months of January and February.This difference might be due to climatic effects and differences in altitude and latitude.Our results are also in contrast with Malik and Malik who reported that maximum flowering occurred during July and August in the Ganga Chotti and Beddori hills of Azad Kashmir, which again may be due to a higher altitude, rainfall and saturation in their study area [61].With a change in climatic conditions, the flowering period of plant species can be affected.A change in temperature can cause a shift in the reproductive phenology of plant species [62].An increase in temperature advances the phenology of many plant species [63].In the investigated area many herbaceous species were in flowering condition in the month of March when there was a slight increase in temperature otherwise flowering occurred in the month of April.So our findings are in accordance with previous reports.Nautiyal and his coworkers reported that flowering in many plant species of the alpine zone occurred after snow fall [64].In the investigated area flowering started in the month of March for the majority of the woody plant species so our findings in this regard are in accordance with this study.The majority of tree species were in flower during April which is also in accordance with Dar and Malik, who reported maximum flowering among the tree species during April while working in Lawat district, Azad Kashmir [65].
Golluscio and his coworkers observed that grasses, members of Poaceace, had the majority of their phenological activities during the autumn and winter seasons as compared to the non-grass plant species which had different starting and ending dates of vegetative and reproductive growth [66].In our case too most of the grasses bloomed in autumn and early winter so our finding is in line with this.Changes in climatic factors such as temperature and humidity can produce changes in the phenology of the plant species.Similarly urbanization is a major factor of global climatic change.There was an uneven fluctuation in temperature throughout the year in urban areas of Canada which has direct impact on vegetation phenology [67].Similarly in our case, rise in temperature from March to May favored the flowering of plants and further increase in temperature caused onset and maturation of fruits from June -September.Biotic factors can also have a profound influence on the plant phenological events [68].This has been observed in our case as temperatures generally decreased during October and November to promote leaf fall and in June and July the grazing pressure increased which facilitated the second dormant phase.The grazing of annual herbaceous plant species prior to flowering will restrict the population because in this case seeds will be the only propagation source for regeneration and survival.Therefore it is essential to coordinate the grazing period with the flowering cycle in order to promote sustainable use of plant resources.

Conclusion
The district Kotli is rich in biodiversity.The high percentage of therophyte and nanophyllous species are due to the subtropical climate of area.The high proportion of therophyte also reflect that area is under sever biotic pressure due to deforestation and overgrazing Majority of species are becoming endangered in the area, therefore immediate conservations measures are needed to preserve the endangered flora.The grazing of annual herbaceous plant species prior to flowering will restrict the population because in this case seeds will be the only propagation source for regeneration and survival.Therefore it is essential to coordinate the grazing period with the flowering cycle in order to promote sustainable use of plant resources.

Figure 1 .
Figure 1.Shows the location of the various sampling sites used in this study

Figure 5 .
Figure 5. Graphical representation of seasonal variation in leaf spectra

Figure 6 .Figure 7 . 1 , 15 , 27 , 37 ]
Figure 6.Wards cluster analysis dendrogram based on the phenological pattern of the vascular flora of Kotli District, AJ&K Three different forest types have been recognized in the area, namely subtropical scrub forest, subtropical chir pine forest and subtropical broad leaf humid forest.The highest average monthly precipitation is recorded during the month of July (291 mm), while the lowest average monthly precipitation of 19 mm occurs during the month of November.Temperatures reach a peak during June and July, with average daily minimum temperatures of 23.

Appendix I. Floristic composition, Biological Spectrum and phenology of plant species recorded from District Kotli, Azad Jammu & Kashmir Division/Family S. No Species Seasonality Life Form Leaf Spectra Phenology Monsoon Spring A. Pteridophytes
, Badsha et al (2013) and Ali et al.

18, 23, 25, 28].
This is because in dry areas and particularly in mountains, the soil has a low nutrient and water content making it difficult for plant roots to absorb moisture and nutrient and thus encouraging the dominance of nanophyllous and leptophyllous vegetation, as was observed in our study area.The ratio of different leaf size classes changes during different seasons in the study area due to the presence of annuals and rhizomatous geophytes.Malik and his coworkers and Batalha and Martins also reported that leaf size is directly related to the soil conditions and the availability of moisture [

18, 23, 55].
Leaf size alone could not be used to identify the climate or specific zone of the investigated area; root system and the habit of plants might play an equal role.