Floristic Composition of Dahab Island at Nile Region, Egypt

Transcription

1 Current Science International Volume : 06 Issue : 04 Oct.- Dec Pages: Floristic Composition of Dahab Island at Nile Region, Egypt Nael M. Fawzi, Hanan S. Abdelmaksoud and Safwat A. Azer Flora and Phytotaxonomy Researches Department, Horticultural Research Institute, Agricultural Research Center, Giza, Egypt Received: 20 August 2017 / Accepted: 10 Oct / Publication Date: 30 Oct ABSTRACT This research aimed to study the floristic composition among different habitats at Dahab Island, Giza, Egypt. Ninety one species, belong to 27 dicotyledon and 5 monocotyledon families, were recorded and identified with Egyptian floras and available checklists. The life span showed that winter, summer and all-year annual species were represented by 57 species (62.64%), while herb and woody perennials were 34 species (37.36%). Moreover the low number of woody perennial species was related to the high intensity of disturbance due to agricultural activities in the field crops and orchards habitats. The woody perennial species were not recorded at water bodies habitat. In terms of abundance and distribution species of Poaceae, Compositae and Leguminosae were found to be the dominant species. The wide distribution of some species among the studied habitats may be interpreted as common or dominant species. Cynodon dactylon was the most dominant species at all studied habitats except the water body's ones, while Cyperus rotundus was the dominant species at irrigation canals and orchards habitats. The monotypic genera showed the higher distribution more than the polytypic ones. In addition, the polytypic families and genera were not noticed at water bodies habitat. Key words: Floristic composition, life span ratio, frequency ratios, polytypic, monotypic, Dahab Island Introduction The Nile system has been subjected to large scale schemes of river control, as barrages and dams which have been built across the Nile. These have segmented the natural hydro biological system (Kassas, 1971). Islands differ in their geological, geomorphological, geography, biological and climatic (Maul, 1993 and Leatherman, 1997). River islands have an economic value since they have high potential for all types of development. The erosion and sedimentation processes in islands are affected by the changes in the hydraulic characteristics and human interventions (Sadek, 2013). The construction of Aswan High Dam during 1960s affected the river morphology including islands formation and types (Sadek, 2013). In Egypt, Nile islands are the real breathing space for its surrounding areas (Farag et al., 2013). The narrow areas of the fertile lands of the River Nile region occupy less than 5% of total area of Egypt. They represent the backbone of the cultivation of the traditional crops that are fully utilizing the freshwater of the River Nile (Zahran et al., 2014). In addition, El-Abassery and Hassan (2008) proposed that there are some 500 islands in the main stream of the Nile and its Rosetta and Damietta branches. Moreover, El-Hadidi and Hosni (2000) indicated that these islands have great diversity in origin, size and structure; 144 of them have been designated as protected areas and spread over 16 governorates; 27 of these protected islands are located at Aswan (Amer, 2009). Also, Amer et al. (2015) showed that Beni-Suef governorate has 46 islands that differ in length, width and space. The greater Cairo area has six islands: Canataire, Dahab, Qusairah, Rawdah,Waraq and Zamalek. Dahab Island located in the Nile phytogeographical region and belongs to Giza governorate. The island located between latitude 29 58' 26" N and longitude 31 12' 50" E. The total area of the island is approximately 4.1km x 0.67km (Farag et al., 2013). Most of the rains fall in winter months. The main winter crops are clover and wheat; while summer ones are maize and beans. Water for irrigation is raised from the River Nile into irrigation canals and then to the fields. Corresponding Author: Safwat A. Azer, Flora and Phytotaxonomy Researches Department, Horticultural Research Institute, Agricultural Research Center, Giza, Egypt. safwat.azer@hotmail.com 729

2 Many floristic studies were conducted on the riverian islands of Egypt; Springuel (1981) studied the natural vegetation of the islands at Aswan. El-Khatib (1997) described the current and past vegetation types of Kraman islands in the River Nile at Sohag Governorate. Mohamed and Hassan (1998) conducted a study on the plant life through 43 Nile islands of El Minia governorate and recorded 95 species. Abd El-Ghani (2001) stated that the studies on the vegetation of aquatic ecosystems on the Nile islands have received little attention. Hamada (2004) studied the plant life of seven islands in the Nile stream at Aswan governorate. Shaheen et al. (2004) recorded 206 species in a study of botanical diversity in the flora of some islands in the Egyptian Nubia. Hamed et al. (2012) worked on some riverian islands at Qena governorate. Amer et al. (2015) worked on the some islands at Beni-Suef governorate with special reference to the migration route. Recently, Azer et al. (2016) studied the floristic composition of Waraq Island at Giza governorate and recorded 116 species. This study was carried out to identify the floristic composition at Dahab Island and demonstrate the abundance and life span ratios of winter, summer, all year annual species and herb and woody perennial speciesamong six studied habitats namely; field crops, irrigation canals, Nile banks, orchards, wastelands and water bodies. Material and Methods The study area The study area extends along the River Nile and belongs to Giza governorate (Figure 1). The island located between latitudes 29º N and altitudes 31º E. The total area of the island is approximately 4.1km x 0.67km. The climate of the study area is characterized by two distinct seasons: a rainy season from December through March and a dry season which runs from May through October. Values of relative humidity were less in winter months than summer months. Species collection and identification Several visits were performed to the studied area to cover all the studied habitats from July 2016 to July The studied species were recorded to represent the plant diversity and covered the studied habitats at Dahab Island. The recorded species were arranged alphabetically (Tables 1-6). The identification of the collected species were carried on according to Täckholm (1974) and Boulos (1995, 1999, 2000, 2002, 2005 and 2009), and were updated by Angiosperm Phylogeny Group III (2009); Chase and Reveal (2009) and Haston et al. (2009). Voucher specimens were collected and identified at the herbarium of Flora and Phytotaxonomy Researches Department (CAIM), Horticultural Research Institute, Agricultural Research Center. One hundred and fifteen plant specimens were collected and prepared as herbarium sheets. Floristic sampling A total of 18 locations (3 locations per each habitat) and a total of 138 quadrates have been chosen to cover the variations of six different habitats at Dahab Island. The quadrates were chosen as the following: 30 quadrates in field crops habitat (10 quadrates per each location), 18 quadrates in irrigation canals habitat (6 quadrates per each location), 27 quadrates in Nile banks habitat (9 quadrates per each location), 21 quadrates in orchards habitat (7 quadrates per each location), 24 quadrates in wastelands habitat (8 quadrates per each location) and 18 quadrates in water bodies habitat (6 quadrates per each location). The size of the sample quadrates were varied from one habitat to another, depending on species richness variability among the studied habitats. Categories of plant species Frequency of species (F %) was calculated as the number of quadrates where the species was recorded divided by the total number of quadrates at each habitat (Shaltout et al., 1992; Abd El-Ghani et al., 2013 and Soliman et al., 2015). The species reported within habitats were classified into three categories according to Abd El-Raouf et al. (1993); Soliman et al. (2009) and were modified by the 730

3 authors as following: dominant 40% frequency, common > 15-40% frequency and rare 15% frequency. Fig. 1: A map shows the location of Dahab island at Nile region, Giza governorate, Egypt (source: Google Earth) Statistical analysis Statistical analysis of the studied species was based on Microsoft Office Excel to measure the following criteria: (1) Frequency ratios of the recorded species. (2) The variations of growth form and species abundance ratios. (3) Monotypic and polytypic species and genera. (4) See once species ratios among the studied habitats at Dahab Island. Results and discussion General distribution patterns of species The winter, summer and all- year annual species constituted the main bulk of the total flora at Dahab Island, where 57 species (62.64% of the total) were recorded and identified. The short life cycle of annuals, as well as the prevailing climatic conditions and water availability, lead to their frequent occurrence (Shaltout and El-Fahar, 1991 and Soliman et al., 2015). The dominance of annual species related to their high reproductive capacity and ecological, morphological, and genetic plasticity under high levels of disturbance (Grime, 1979 and Abd El-Ghani et al., 2013). The low number of herb perennials (22 species) and woody perennials (12 species: includes 7 shrubs and 5 trees) might be related to the intensive management used in the plantations which could affect vegetative growth structures (Abd El-Ghani, 1994; Abd El-Ghani and El-Sawaf, 2004 and Abd El- Ghani et al., 2013). In the current investigation, the wide distribution of some species among the represented habitats may be interpreted as common or dominant species. Species with wide ecological amplitude (e.g., Cynodon dactylon and Cyperus rotundus) were caused by phenotypic plasticity and heterogeneity (Shaltout and Sharaf El-Din, 1988 and Abd El-Ghani et al., 2013). The restricted distribution of some species, such as Mentha longifolia subsp. typhoides in irrigation canals habitat, Alternanthera sessilis, Ranunculus sceleratus and Veronica anagallis- aquatica in Nile banks habitat 731

4 as well as Glinus lotoides, Juncus subulatus, Calotropis procera and Tamarix nilotica in wastelands habitat can be attributed to the habitat preference phenomenon. In line with this, Abd El-Ghani and Fawzy (2006) and Abd El-Ghani et al. (2013) discussed this phenomenon in the farmlands of the Egyptian habitats. They concluded that each of the 5 distinguished habitats (farmlands, canal banks, reclaimed lands, wastelands, and water bodies) has its own preferential species. Ecological status of plant species The frequency ratios of the species were generally varied among the studied habitats at Dahab Island (Tables 1-6). Cynodon dactylon was the most dominant species at the five represented habitats except the water bodies' ones. The highest ratio of frequency 100% (Table 2) was recorded at irrigation canals habitat followed by 62.96% at Nile banks one (Table 3). Cyperus rotundus L. was the dominant species at irrigation canals habitat (Table 2). In addition, at the water bodies habitat, Ceratophyllum demersum was the dominant species followed by Potamogeton nodosus. They were represented by 53.33% and 40%; respectively (Table 6). The findings from this study showed that the distribution of plant species represented by frequency ratios showed notable variation among the studied habitats (Abd El-Ghani and El-Bakry, 1992). The high diversity of plant species could also be due to the differences in seed production, dispersal, germination and seedling establishment (Newman, 1994; Essandoh et al., 2011 and Soliman et al., 2015), which promote high levels of coexistence among the recorded plant species. Floristic composition A total of 91 species of vascular plants belong to 33 families were recorded and identified among the studied habitats (Tables 1-6). The most common families were Poaceae 21 species and Compositae 9 species, followed by Leguminosae 7 species. Moreover, Brassicaceae, Convolvulaceae and Euphorbiaceae were represented by (4 species). In addition, 13 families were monotypic and constituted 14.29% of the total recorded families. Generally, the total number of genera within each family followed the same sequence for the total number of species. Genera with highest number of species included Cyperus and Euphorbia (3 species each) were recorded during this study. The findings of the current investigations were in agreement with (Abd El-Ghani et al., 2013; Azer, 2013; Amer et al., 2015 and Azer et al., 2016). Life-span or "plant longevity" ratios The data in Figure (2) showed that, the highest ratio 61% of winter annual species was noticed at field crops habitat followed by 42% at irrigation canals habitat, while the lowest one 15% was recorded at Nile banks habitat. Similarly, the highest ratio 18% of summer annual species was recorded at both irrigation canals and orchards habitats, while the lowest ratio 4% was recorded at Nile banks habitat. In addition, all-year annual species showed the highest ratio 21% at orchards habitat followed by 11% at field crops habitats, while the lowest ratio 2% was recorded at Nile banks habitats. In addition the highest ratio 100% of herb perennial species was recorded at water bodies habitat followed by 44% at Nile banks habitat, while the lowest one 11% was recorded at field crops habitat. Similarly, the highest ratio 30% of woody perennial species was recorded at Nile banks habitat followed by 18% at wastelands habitat, while the lowest one 3 % was noticed at orchards habitat. On the whole, winter, summer and all-year annual species and woody perennial species were not noticed at water bodies' habitat. Plant longevity (life span) within the area under study showed remarkable variations. The notable aspects of these variations are due to the growth of annual species. They usually appear in late winter or early spring in abundant number of individuals. Our results support the conclusions of (Abd El-Ghani, 1994 and Al Wadie, 2002). On the other hand, the low number of herb and woody perennial species in the study area was due to the human factors which contributed to the disruption of natural equilibrium among the component of the ecosystem that causing its deterioration. These findings are in agreement with Abd El-Ghani and Bakry, (1992); Abd El-Ghani (1994 and 1998) and Abd-El Ghani and El-Sawaf (2004). 732

5 Table 1: List of recorded species with their frequency ratios in field crops habitat at Dahab Island No. of quadrates recorded by species/location Taxa Families Location 1 Location 2 Location 3 Total quadrates *Frequency ratio *Abundance WINTER ANNUALS SPECIES 1 Ammi majus L. Apiaceae R 2 Anagallis arvensis L. Primulaceae R 3 Avena fatua L. Poaceae C 4 Beta vulgaris L. Chenopodiaceae C 5 Chenopodium album L. Chenopodiaceae D 6 Chenopodium murale L. Chenopodiaceae C 7 Cichorium endivia L. subsp. divaricatum Compositae C (Schousb.) P.D. Sell 8 Coronopus didymus (L.) Sm. Brassicaceae R 9 Cyclospermum leptophyllum Apiaceae C 10 Emex spinosa (L.) Campd. Polygonaceae C 11 Eruca vesicaria (L.) Cav. Brassicaceae C 12 Euphorbia peplus L. Euphorbiaceae C 13 Lolium perenne L. Poaceae C 14 Malva parviflora L. Malvaceae C 15 Melilotus indicus (L.) All. Leguminosae R 16 Phalaris minor Retz. Poaceae C 17 Poa annua L. Poaceae D 18 Raphanus raphanistrum L. Brassicaceae R 19 Senecio aegyptius L Compositae C 20 Spergularia diandra (Guss.) Heldr. & Caryophyllaceae C Sart. 21 Trifolium alexandrinum L. Leguminosae C 22 Trifolium resupinatum L. Leguminosae R 23 Urtica urens L. Urticaceae R SUMMER ANNUALS SPECIES 24 Amaranthus lividus L. Amaranthaceae C 25 Amaranthus viridis L. Amaranthaceae C 26 Corchorus olitorius L. Malvaceae R 27 Euphorbia heterophylla L. Euphorbiaceae C 28 Portulaca oleracea L. Portulacaceae C ALL YEAR ANNUALS SPECIES 29 Cuscuta campestris Yuncker Convolvulaceae R 30 Polypogon monspeliensis (L.) Desf. Poaceae C 31 Solanum americanum Mill. Compositae C 32 Sonchus oleraceus L. Compositae R HERB PERENNIAL SPECIES 33 Convolvulus arvensis L Convolvulaceae D 34 Cynodon dactylon (L.) Pers. Poaceae D 35 Cyperus rotundus L. Cyperaceae C 36 Orobanche ramosa L. Orobanchaceae D WOODY PERENNIAL SPECIES 37 Phoenix dactylifera L. Arecaceae C 38 Sesbania sesban (L.) Merr. Leguminosae R * Frequency ratios= Total number of quadrates where the species was recorded divided by the total number of quadrates (30). *Abundance ratios= (D = dominant 40% frequency), (C= common > 15-40% frequency), (R = rare 15% frequency). 733

6 Table 2: List of recorded species with their frequency ratios in irrigation canals habitat at Dahab Island No. of quadrates recorded by species/location Taxa Families Location 4 Location 5 Location 6 Total quadrates *Frequency ratio *Abundance WINTER ANNUALS SPECIES 1 Capsella bursa-pastoris (L.) Medik. Brassicaceae C 2 Chenopodium album L. Chenopodiaceae D 3 Chenopodium murale L. Chenopodiaceae C 4 Cichorium endivia L. subsp. divaricatum Compositae C (Schousb.) P.D. Sell 5 Euphorbia peplus L. Euphorbiaceae C 6 Laphangium luteoalbum (L.) Tzvelev Compositae C 7 Lepidium didymum L. Brassicaceae C 8 Oxalis corniculata L. Oxalidaceae C 9 Plantago major L. Plantaginaceae C 10 Poa annua L. Poaceae C 11 Rumex dentatus L. Polygonaceae C 12 Sisymbrium irio L. Brassicaceae C 13 Trifolium alexandrinum L. Leguminosae C 14 Trifolium resupinatum L. Leguminosae C SUMMER ANNUALS SPECIES 15 Amaranthus lividus L. Amaranthaceae C 16 Brachiaria mutica (Forssk.) Stapf Poaceae C 17 Corchorus olitorius L. Malvaceae C 18 Echinochloa colona (L.) Link Poaceae D 19 Eclipta prostrata (L.) L. Compositae C 20 Euphorbia heterophylla L. Euphorbiaceae C ALL YEAR ANNUALS SPECIES 21 Polypogon monspeliensis (L.) Desf. Poaceae C 22 Solanum americanum Mill. Solanaceae C 23 Sonchus oleraceus L. Compositae C HERB PERENNIAL SPECIES 24 Adiantum capillus-veneris L. Pteridaceae R 25 Convolvulus arvensis L. Convolvulaceae C 26 Cynanchum acutum L. Apocynaceae C 27 Cynodon dactylon (L.) Pers. Poaceae D 28 Cyperus rotundus L. Cyperaceae D 29 Imperata cylindrica (L.) P.Beauv. Poaceae C 30 Ipomoea cairica Sweet Convolvulaceae C 31 Mentha longifolia (L.) Huds. subsp. Lamiaceae R+ typhoides (Briq.) Harley 32 Pluchea dioscoridis (L.) DC. Compositae C WOODY PERENNIAL SPECIES 33 Ricinus communis L. Euphorbiaceae C * Frequency ratios= Total number of quadrates where the species was recorded divided by the total number of quadrates (18). *Abundance ratios= (D = dominant 40% frequency), (C= common > 15-40% frequency), (R = rare 15% frequency). + = See once species 734

7 Table 3: List of recorded species with their frequency ratios in Nile banks habitat at Dahab Island No. of quadrates recorded by species/location Taxa Families Location 7 Location 8 Location 9 Total quadrates *Frequency ratio *Abundanc e WINTER ANNUALS SPECIES 1 Eruca vesicaria (L.) Cav. Brassicaceae R 2 Laphangium luteoalbum (L.) Tzvelev Compositae R 3 Ranunculus sceleratus L. Ranunculaceae R+ 4 Raphanus raphanistrum L. Brassicaceae R SUMMER ANNUALS SPECIES 5 Alternanthera sessilis (L.) R.Br. ex DC. Amaranthaceae R+ ALL YEAR ANNUALS SPECIES 6 Juncus bufonius L. Juncaceae R 7 Solanum tuberosum L. Solanaceae R HERB PERENNIAL SPECIES 8 Cynodon dactylon (L.) Pers. Poaceae D 9 Cyperus alopecuroides Rottb. Cyperaceae C 10 Cyperus schimperianus Steud. Cyperaceae R 11 Datura stramonium L. Solanaceae R+ 12 Imperata cylindrica (L.) P.Beauv. Poaceae C 13 Ipomoea cairica Sweet Convolvulaceae C 14 Juncus inflexus L. Juncaceae C 15 Phragmites australis (Cav.) Trin. ex Steud. Poaceae C 16 Pluchea dioscoridis (L.) DC. Compositae D 17 Saccharum spontaneum L. Poaceae C 18 Typha domingensis Pers. Typhaceae C 19 Veronica anagallis- aquatica L. Plantaginaceae R+ WOODY PERENNIAL SPECIES 20 Acacia nilotica (L.) Willd. ex Del. Leguminosae R+ 21 Arundo donax L. Poaceae C 22 Ipomoea carnea Jacq. Convolvulaceae C 23 Leucaena leucocephala (Lam.) de Wit Leguminosae C 24 Phoenix dactylifera L. Arecaceae C 25 Ricinus communis L. Euphorbiaceae C 26 Salix mucronata Thunb. Salicaceae C 27 Salix tetrasperma Roxb. Salicaceae C * Frequency ratios= Total number of quadrates where the species was recorded divided by the total number of quadrates (27). *Abundance ratios= (D = dominant 40% frequency), (C= common > 15-40% frequency), (R = rare 15% frequency). + = See once species 735

8 Table 4: List of recorded species with their frequency ratios in orchards habitat at Dahab Island No. of quadrates recorded by species/location Taxa Families Location 10 Location 11 Location 12 Total quadrates *Frequency ratio *Abundance WINTER ANNUALS SPECIES 1 Bidens pilosa L. Compositae R 2 Chenopodium album L. Chenopodiaceae C 3 Chenopodium murale L. Chenopodiaceae C 4 Cyclospermum leptophyllum (Pers.) Apiaceae R Sprague 5 Emex spinosa (L.) Campd. Polygonaceae C 6 Euphorbia peplus L. Euphorbiaceae C 7 Malva parviflora L. Malvaceae R 8 Melilotus indicus (L.) All. Leguminosae R 9 Poa annua L. Poaceae R 10 Sisymbrium irio L. Brassicaceae R SUMMER ANNUALS SPECIES 11 Amaranthus viridis L. Amaranthaceae C 12 Digitaria sanguinalis (L.) Scop. Poaceae C 13 Echinochloa colona (L.) Link Poaceae C 14 Euphorbia heterophylla L. Euphorbiaceae C 15 Portulaca oleracea L. Portulacaceae C 16 Trianthema portulacastrum L. Aizoaceae C ALL YEAR ANNUALS SPECIES 17 Bidens pilosa L. Compositae R 18 Brachiaria mutica (Forssk.) Stapf Poaceae C 19 Plantago major L. Plantaginaceae C 20 Polypogon monspeliensis (L.) Desf. Poaceae C 21 Setaria verticillata (L.) P. Beauv. Poaceae C 22 Solanum americanum Mill. Solanaceae C 23 Sonchus oleraceus L. Compositae R HERB PERENNIAL SPECIES 24 Convolvulus arvensis L. Convolvulaceae C 25 Cynanchum acutum L. Apocynaceae D 26 Cynodon dactylon (L.) Pers. Poaceae D 27 Cyperus rotundus L. Cyperaceae D 28 Desmostachya bipinnata (L.) Stapf Poaceae C 29 Leptochloa fusca (L.) Kunth Poaceae R 30 Paspalidium geminatum (Forssk.) Stapf Poaceae R 31 Pluchea dioscoridis (L.) DC. Compositae C 32 Withania somnifera (L.) Dunal Solanaceae R WOODY PERENNIAL SPECIES 33 Phoenix dactylifera L. Arecaceae R * Frequency ratios= Total number of quadrates where the species was recorded divided by the total number of quadrates (21). *Abundance ratios= (D = dominant 40% frequency), (C= common > 15-40% frequency), (R = rare 15% frequency). 736

9 Table 5: List of recorded species with their frequency ratios in wastelands habitat at Dahab Island No. of quadrates recorded by species/location Taxa Families Location 13 Location 14 Location 15 Total quadrates *Frequency ratio *Abundance WINTER ANNUALS SPECIES 1 Bidens pilosa L. Compositae C 2 Chenopodium album L. Chenopodiaceae C 3 Chenopodium murale L. Chenopodiaceae C 4 Euphorbia peplus L. Euphorbiaceae D 5 Lolium perenne L. Poaceae C 6 Malva parviflora L. Malvaceae R 7 Melilotus indicus (L.) All. Leguminosae C 8 Phalaris minor Retz. Poaceae C 9 Plantago major L. Plantaginaceae C 10 Rumex dentatus L. Polygonaceae R 11 Senecio desfontainei Druce Compositae R 12 Sericocarpus linifolius (L.) "Britton, Sterns Compositae C & Poggenb." 13 Spergularia marina (L.) Griseb. Caryophyllaceae R SUMMER ANNUALS SPECIES 14 Corchorus olitorius L. Malvaceae R 15 Digitaria sanguinalis (L.) Scop. Poaceae C 16 Echinochloa colona (L.) Link Poaceae D 17 Portulaca oleracea L. Portulacaceae C 18 Trianthema portulacastrum L. Aizoaceae C ALL YEAR ANNUALS SPECIES 19 Cenchrus barbatus Schum. Poaceae C 20 Glinus lotoides L. Molluginaceae R+ 21 Polypogon monspeliensis (L.) Desf. Poaceae C 22 Solanum americanum Mill. Solanaceae C HERB PERENNIAL SPECIES 23 Convolvulus arvensis L. Convolvulaceae C 24 Cynanchum acutum L. Apocynaceae D 25 Cynodon dactylon (L.) Pers. Poaceae D 26 Cyperus rotundus L. Cyperaceae C 27 Desmostachya bipinnata (L.) Stapf Poaceae D 28 Imperata cylindrica (L.) P.Beauv. Poaceae D 29 Juncus subulatus Forssk. Juncaceae R+ 30 Medicago sativa L. Leguminosae C 31 Phragmites australis (Cav.) Poaceae C 32 Pluchea dioscoridis (L.) DC. Compositae C 33 Withania somnifera (L.) Dunal Solanaceae R WOODY PERENNIAL SPECIES 34 Calotropis procera (Aiton) Dryand. Apocynaceae R+ 35 Ipomoea carnea Jacq. Convolvulaceae C 36 Leucaena leucocephala (Lam.) de Wit Leguminosae C 37 Phoenix dactylifera L. Arecaceae R 38 Ricinus communis L. Euphorbiaceae C 39 Sesbania sesban (L.) Merr. Leguminosae R 40 Tamarix nilotica (Ehrenb.) Bunge Tamaricaceae R+ * Frequency ratios= Total number of quadrates where the species was recorded divided by the total number of quadrates (24). *Abundance ratios= (D = dominant 40% frequency), (C= common > 15-40% frequency), (R = rare 15% frequency). + = See once species 737

10 Table 6: List of recorded species with their frequency ratios in water bodies habitat at Dahab Island No. of quadrates recorded by species/location Taxa Families Location 16 Location 17 Location 18 Total quadrates *Frequency ratio *Abundance HERB PERENNIAL SPECIES 1 Ceratophyllum demersum L. Ceratophyllaceae D 2 Eichhornia crassipes (Mart.) Solms Pontederiaceae C 3 Ludwigia adscendens subsp. diffusa (Forssk.) Onagraceae C P.H.Raven 4 Persicaria maculosa Gray Polygonaceae C 5 Potamogeton nodosus Poiret Potamogetonaceae D * Frequency ratios= Total number of quadrates where the species was recorded divided by the total number of quadrates (18). *Abundance ratios= (D = dominant 40% frequency), (C= common > 15-40% frequency), (R = rare 15% frequency). Annual and perennial species The histogram illustrated on Figure (4a) showed that the highest ratio 84% of the annual species was noticed at field crops habitat followed by 70% at both irrigation canals and orchards habitats, while the lowest one 26% was recorded at Nile banks habitat. Similarly, the highest ratio 100% was recorded at water bodies habitat, followed by 74% at Nile banks one, while the lowest ratio 16% was noticed at field crops habitat. On the whole, the annual species was not noticed at water bodies' habitat. The total number 91 of the recorded species was composed of 57 annual species (62.64%), 22 herb perennial species (24.18%), 12 woody perennial species (13.19%). These agree with Mashaly (2001 and 2002) and Mashaly et al. (2002, 2008 and 2009). The low number of shrubs and trees, in the current study related to the high intensity of disturbance due to agricultural activities in the field crops and orchards; this fact also reported by Abd El-Ghani et al.(2013); Azer (2013); Amer et al. (2015) and and Azer et al. (2016). Monocotyledon and dicotyledon families The data in Figure (4b) showed that the dicotyledon families showed the highest ratio 88% of distribution at field crop habitat followed by 84% at wastelands habitat, while lowest ratio 73% was noticed at Nile banks habitat. In addition, the ratios of monocotyledon families varied among the studied habitats. The highest ratio 27% was recorded at Nile banks habitat, followed by 20% at water bodies habitat, while the lowest one 12 % was noticed at field crops habitat. The four major distributed families were Poaceae 21 species (23.08%), Compositae 9 species (9.89%), Leguminosae 7 species (7.69%) and Brassicaceae 4 species (4.40%). They comprised 41 taxa (45.05%) of the total recorded species. These families were reported earlier by Mashaly et al. (2009); Hamed et al. (2012); Azer (2013) and Amer et al. (2015) and Azer et al., (2016) as the most frequent families in the studied areas. Monotypic and polytypic families The data in Figure (4c) showed that the monotypic families showed the highest ratio 100% of distribution at water bodies habitat followed by 72% and 59% at orchards and irrigation canals habitats; respectively. On the other hand, the lowest ratio 35% was recorded at field crops habitat. In addition, the polytypic families were represented by 65% and 60% at filed crops and Nile banks habitats; respectively. The lowest ratios 28% were recorded at orchards habitat. However, the polytypic families were not noticed at water bodies habitat. The families with the highest richness 738

11 recorded by this study are compatible with the data of Quezel (1978) who reported that, Poaceae, Compositae, Leguminosae and Brassicaceae are among the most common families in the Mediterranean North African flora. Similar conclusion has been reached by Shaheen (2002); Abd El- Ghani and Fawzy (2006); Azer (2013); Amer et al. (2015) and Azer et al. (2016). Monotypic and polytypic genera The data in Figure (4d) revealed that the monotypic genera showed the highest ratio of distribution more than the polytypic ones. The highest ratio 100% of the monotypic genera was recorded at water bodies habitat followed by 96% and 95% at both Nile banks and wastelands habitats; respectively while the lowest one 89% was mentioned at field crops habitat. Similarly, the ratios of polytypic genera varied among the studied habitats. The highest two ratios 11% and 9% were recorded at filed crops and irrigation canals habitats; respectively while, the lowest ratio 4% were noticed at Nile banks habitats. However, the polytypic ones were not recorded at water bodies habitat. The current investigation is partially in agreement with Shaltout and El-Fahar (1991). See once species The recorded number of see once species was varied among the studied habitats (Tables 2, 3 and 5). One species namely; Mentha longifolia subsp. typhoides was recorded in irrigation canal habitats (Table 2). In addition, five species (5.49%) was recorded in Nile bank habitats (Table 3) which included: Acacia nilotica, Alternanthera sessilis, Datura stramonium, Ranunculus sceleratus and Veronica anagallis-aquatica. Moreover, four species (4.40%); namely Calotropis procera, Glinus lotoides, Juncus subulatus and Tamarix nilotica were recorded in wasteland habitats (Table 5). On the whole, the total numbers of see once species were 10 taxa (10.99%) at Dahab Island (Table 7). Table 7: List of see once species with their numbers and ratios recorded among the studied habitats at Dahab Island. Habitats Total number/habitat No. see once species/habitat Ratio Irrigation canals Nile banks Wastelands Total

12 Fig. 2: Spectrum shows life span ratios among the studied habitats at Dahab Island 740

13 Fig. 3: Spectrum shows species abundance ratio among the studied habitats at Dahab Island 741

14 a b c c d d d Fig. 4: Histogram shows ratios of: annual and perennial species (a), dicotyledon and monocotyledon families (b), monotypic and polytypic families (c) and monotypic and polytypic genera (d) among the studied habitats at Dahab Island 742

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