Plant diversity of five important wetlands of Babol Mazandaran province, Iran

Introduction

Wetlands are valuable ecosystems which provide abundant services and materials with economic value, not only to the adjacent local populations but also to regional communities, providing valuable services such as water quality improvement, flood mitigation, erosion control and recreational enrichment (Mitsch and Gosselink, 2000). Destroying wetlands by means of drainage and pollution, which have derived from wastewater of agriculture and industries are substantial problems for the world wetlands. The occurrence of exotic species such as Azolla filliculoides on the water surface of wetlands is the major concern in these aquatic ecosystems in the north part of Iran. The wetlands of Babol namely Marzoonabad, Langoor, Bosra, Ramenet and Aghoozbon are important ecosystem in the north of Iran. Studying these wetlands is very important because they serve as a very valuable resting, nesting and wintering places for a wide variety of waterfowls. These wetlands also play the critical role in restoring water, which is required for cultivating activities in summer. Because of variety in the climatic conditions, there are rather remarkable and unique wetlands with exclusive characteristic in different parts of Iran. Some floristic and ecological studies have been conducted on these vaulable ecosystems e.g. Hashilan wetland (Karami et al., 2001) in the west and Parishan wetland (Dolatkhahi et al., 2010) in the south of Iran. Nevertheless, many floristic and vegetation studies of the wetland habitats in Iran were concentrated along the southern Caspian shore, i.e. Amirkelayeh lagoon and coasts of Lahijan-Langerud (Asri and Moradi, 2004; Ghahreman et al., 2004), Anzali lagoon (Ghahreman and Attar, 2003; Asri and Eftekhari, 2002), Miankaleh wildlife refuge (Sharifnia et al., 2007; Ejtehadi et al., 2003; Asri et al., 2007), Boujagh National Park (Naqinezhad et al., 2006) , Estil wetland (Khodadadi et al., 2009, Solukli wetland in Golestan national Park (Akhani, 1998), Gomishan lagoon (Karimi, 2010). The aims of the study were to present: (1) a checklist of all vascular plants found in these five wetlands, (2) spectrum of life form and phytogeographical data across the whole wetlands together with detailed information about the habitats, life form and chorology for each species, (3) a comparison between the results of Babol wetlands and other wetlands and (4) a solution for protecting these wetlands from serious destruction.

Materials and Methods

Study area

The wetlands of Babol are located in Mazandaran province, northern Iran, between 52° 35' - 52° 45' E and 36° 31' - 36° 37' N. The studied area covers five wetlands namely Marzoonabad, Langoor, Bosra, Ramenet and Agoozbon. Marzoonabad and Basra wetlands are located beside Babol-Amol road. Langoor and Agoozbon wetlands are near Babol- Bahnamir road and finally Ramenet wetland is placed beside Babol-Kiakola road. All these wetlands are located in the plain part of Babol (Figure 1). There are many cultivated places and also some canals around of the studied wetlands. These canals carry water from wetland to cultivated farms. The total surface and the mean altitude of the Babol wetlands are 1470 ha and 14.7 m respectively. The rainiest month is October. The mean annual precipitation is 738.7 mm and the mean annual temperature is 16.3 °C. The maximum and minimum mean temperatures are 29.3 °C, and 4.5 °C, respectively. The ombrothermic diagram of the studied area was prepared according to climate data obtained from the Gharakheil meteorological station (Figure 2). Three rivers namely Talar, Babol and Haraz provide water for these five wetlands and then empty their water into the Caspian sea.

Data collection and analyses

In order to survey the flora of Babol wetlands, topographic maps were provided at first. Then, the specimens were collected in different seasons. The collected samples were then identified and named based on the classification and terminology applied to various Flora, such as: Flora Iranica (Rechinger, 1963-1998), Flora of Iran (Assadi, 1988-2007) and Flora of Turkey (Davis, 1965-1988). All plant specimens were deposited in the Farabi Herbarium (FAR), Tehran. Life forms were named following the Raunkiaer’s classification (Raunkiaer, 1934) and chorology of species is based on Zohary (1973) and Takhtajan (1986) viewpoints. The habitat and color flower of each species were carefully noted while collecting the samples.

Results and discussion

In this study, a total of 196 species of vascular plants were identified from Babol wetlands, which belonged to 58 families and 138 genera. There were different number of families, genera and species amoung various taxonomic groups (Table 1). The richest families in terms of the number of taxa were Poaceae (24), Cyperaceae (19), Asteraceae (16) and Fabaceae (13) respectively. Nine families possessesed two taxa and the remaining 28 families had just one taxon. As for the species richness, genera with four and exceeding species were: Cyperus (eight species), Polygonum (seven species), Potamogeton (four species), Juncus (four species), Carex (four species), Trifolium (four species) and Typha (four species). The most species-rich wetland was Marzoonabad with 111 plant taxa and the lowest species-rich wetland was Aghoozbon with 30 plant taxa. This could be due to the occurrence of more divers’ habitats and different surface area in the Marzoonabad wetland. In Langoor wetland, there were 63 taxa from 56 genera and 31 families. There were 111 plant taxa from 86 genera and 45 families in the Marzoonabad wetland. In Bosra wetland, there were 51 plant taxa from 42 genera and 26 families. In Ramenet wetland, 43 plant taxa from 38 genera and 21 families were collected and determined. In a study on Aghoozbon wetland, 30 plant taxa within 27 genera and 18 families were determined. The ratios of species/genera and genera/families for the Babol wetlands indicated a higher taxonomic diversity as compared to other wetland areas, but these wetlands had fewer species than others, because of lower surface area and higher habitat homogeniety (Table 2).

Table 1. The number of families and genera in the taxonomic groups

Table 2. Comparative floristic richness and taxonomic diversity. Myankaleh (Ejtehadi et al., 2003); Anzali (Ghahreman and Attar, 2003); Amirkelayeh(Ghahreman et al., 2004); Boujagh (Naqinezhad et al., 2006); Fereydoonkenar (Hoseinzadeh, 2007).

Vegetation of the wetlands

The main structure of vegetation of whole areas of the studied wetlands were relatively similar to the vegetation of other wetlands of the northern Iran (e.g. Naqinezhad et al., 2006; Asri and Eftekhari, 2002). The vegetation of these five wetlands were also relatively different from each other. The Langoor wetland which had the surface area more than 700 ha was the largest wetland in Babol. Nymphaea alba was the dominant aquatic plant in this wetland. This plant was considered as a monodominant vegetation in this wetland in the area. The Marzoonabad wetland which had the surface area as much as 400 ha was located in second status. There were many plant communities such as Nymphaea alba-Nelumbium nuciferum and Phragmites australis-Sparganium erectum in the wetland. The Bosra wetland which was more than 150 ha had the marshy mood in some parts. The special characteristic of this wetland was the occurrence of high density of Phragmites australis that served as a very valuable nesting places for lots of waterfowls. There was an obvious community of Typha domingensis-Sparganium erectum in the Ramenet wetland. Finally, one of the major characteristics of the Aghoozbon wetland was the occurence of Paspalum distichum vegetation in its Islands.

A floristic resemblance study was done to show the level of similarity between the five wetlands, using Sørensen’s (1948) similarity index (Table 3). Based on the obtained results the similarity level varied between 4.1% (Ramenet-Aghoozbon) to 29.8% (Marzoon abad-Langoor). This revealed that the floristic similarity was related to each wetland surface area and immigration of the variety of waterfowl that was carried plants seeds from other wetlands (Naqinezhad et al., 2006). It can be seen frequently between Marzoonabad and Langoor wetlands. Furthermore, less similarity between Ramenet and Aghoozbon wetlands was derived mostly from human activities and their relatively far distance. Moreover, frequency of species in each wetland indicated that with the increase in wetland surface, the number of species increases except for the Langoor wetland. This could be due to water deficiency, human interference and lack of migratory waterfowls in the Langoor wetland (Figure 3).

Table 3. Comparison of the flora of the five wetlands with each other using Sørensen’s coefficient (references are as Table 1) (in percentage).

Figure 3. The number of species according to their surface area in the five wetlands of study area

Life forms

In the total assessment of life from spectrum, therophytes made up 37% of the vegetation and were the dominant biological type in the studied area, followed by hemicryptophytes with 20%, as the second dominant life form (Figure 4). Although, therophytes occurred abundantly in desert areas (Archibold, 1995), its high presence was attributed to human activities and extensive grazing. This effect was previously observed in other studied ecosystems as well (Ghahreman et al., 2006; Ejtehadi et al., 2003; Khodadadi et al., 2009).

Chorological spectrum

The chorotype distributions of species in these five wetlands are as given (Figure 5). As it is shown, the flora of the study areas is much affected by pluriregional elements due to two reasons. First, the humid and wet habitats dominating the area, that harbor the bulk of the pluriregional plants adapted to wet places. Second, human activities that are responsible for the establishment of widespread weeds (Archibald, 1995; Naqinezhad et al. 2006).

Habitat

The results of this study showed the existence of three different habitats in the studied area as follows (Figure 7):

1-Habitat for marginal plants: These habitats were usually situated on wet places near to wetlands, plains, rivers, etc. i.e. Euphorbia helioscopia, Marrubium vulgare, Fimbristylis bisumbellata, Silene latifolia, Juncus acutus, Lathyrus hirsutus, Bupleurum marschallianum, Polygonum lapathifolium, Ranunculus marginatus, Verbascum punalense.

2-Habitat for the emergent plants, these habitats contained marshlands and places out of open water area. Plants of this habitat had the high ability to absorb large amount of water. These habitats placed at second status after marginal habitats. Some species of this habitat were: Hydrocotyle vulgaris, Oenanthe aquatica, Eclipta prostrata, Nasturtium microphyllum, Lythrum salicaria, Samolus valerandi, Ranunculus ophioglossifolius, Carex songorica, Sparganium erectum, Sagittaria sagittifolia, Phragmites australis.

3-Habitat for open water plants: These parts were characterized with some floating and submerged plants. There were fewer species existed in this habitat. Species adapted to these habitats were: Ceratophyllum demersum, Salvinia natans, Callitriche brutia, Batrachium trichophyllum, Lemna minor, Nympha alba.

A column in Table 4 is relevant to habitat diversity of plant species.The number of plant species (in number) which can be found in each habitat is summarized in Figure 6.

Table 4. Floristic list of the five important wetlands of Babol.

Symbols and abbreviations used in the table:

Life form: Geo (geophyte), Hel (helophyte), Hem (hemicryptophyte), Hyd (hydrophyte), Pha (phanerophyte), Thr (therophyte)

Chorotype: COSM (cosmopolitan), ES [Euro-Sibirian (Eux-Hyr=Euxino-Hyrcanian, Hyr=Hyrcanian], IT (Irano-Turanian), M (Mediterranean), PL (pluriregional)

Habitat and Ecology: Aq (aquatic habitats), Em (emergent plant), Fl (floating plant), Hyg (hygrophyte), Ma (marginal plant), Su (submerged plant)

Location: AW (Aghoozbon wetland), BW (Bosra wetland), LW (Langoor wetland), MW (Marzoonabad wetland), RW (Ramenet wetland).