ABSTRACT:
Fayoum region is the most fertile agricultural land in Egypt and one of the oldest agricultural city in the world. The present study aimed to determine its weed flora composition and its distribution through different habitats. Results recorded 175 species of vascular plants belonging to 124 genera and 35 families distributed in eight habitats. The richest families were Poaceae, Asteraceae (Compositae) and Fabaceae (Leguminoseae), while genera with the highest number of species were Euphorbia, Amaranthus and Cyperus. Cynodon dactylon and Alhagi graecorum were the present species, recorded at all habitats. Old cultivated lands recorded the highest species number followed by orchard habitats, on the contrast road side and wasteland habitats recorded the lowest species numbers. Therophytes were the dominant life form, while Phanerophytes were the smallest group in this study, 5%. The highest Jaccard similarity index was recorded between healthy land and orchard habitats, which supported also by ward classification.
Keywords:
arable fields; weed; therophytes; agriculture; flora
RESUMO:
A região de Faium é a área agrícola mais fértil do Egito e uma das mais antigas cidades agrícolas do mundo. O presente estudo teve como objetivo determinar a composição da flora de plantas daninhas e sua distribuição através de diferentes habitats. Os resultados registraram 175 espécies de plantas vasculares pertencentes a 124 gêneros e 35 famílias, distribuídos em oito habitats. As famílias mais ricas foram Poaceae, Asteraceae (Compositae) e Fabaceae (Leguminoseae), enquanto os gêneros com maior número de espécies foram Euphorbia, Amaranthus e Cyperus. Cynodon dactylon e Alhagi graecorum foram as espécies presentes, registradas em todos os habitats. As antigas terras cultivadas registraram o maior número de espécies, seguidas dos habitats com pomares, ao contrário das margens de estradas e dos habitats de terras baixas, que registraram o menor número. Os terófitos foram a forma de vida dominante, e os fanerófitos foram o menor grupo neste estudo (5%). O maior índice de similaridade de Jaccard foi registrado entre as terras saudáveis e o habitat com pomares, o que também foi confirmado pelo método de Ward.
Palavras-chave:
terra arável; plantas daninhas; terófitos; agricultura; flora
INTRODUCTION
Weeds are defined as any plant that is objectionable or interferes with the activities or welfare of man (Vencill, 2002Vencill W. Herbicide handbook. Lawrence: Weed Science Society of America, 2002. 493p.). Their role is manifold from an agronomic point of view; they represent a major barrier to farmers in terms of harvest losses caused by their presence because they compete for different resources, such as nutrient and water (Wang et al., 2007Wang S. et al. UV-B radiation increases paraquat tolerance of two broad-leaved and two grass weeds in relation to changes in herbicide absorption and photosynthesis. Weed Res. 2007;47:122-8.). Some weeds are also allelopathic, which affects yields more adversely (Al-Sherif et al., 2013Al-Sherif, E., Hegazy, A.K., Gomaa, N.H., Hassan, M.O. Allelopathic effect of black mustard tissues and root exudates on some crops and weeds. Planta Daninha. 2013;31(1):11- 9.; Trezzi et al., 2016Trezzi M.M. et al. Allelopathy: driving mechanisms governing its activity in agriculture. J Plant Interact. 2016;11:53-60.). By contrast, there is considerable evidence that arable weeds play an important role in providing resources and habitat to higher trophic levels by supplying food and shelter to a wide variety of farmland fauna (Storkey and Westbury, 2007Storkey J., Westbury D.B. Managing arable weeds for biodiversity. Pest Manag. Sci. 2007;63:517-23.; Al Sherif, 2009Al-Sherif E. Melilotus indicus (L.) All., a salt-tolerant wild leguminous herb with high potential for use as a forage crop in salt-affected soils. Flora. 2009;204:737-46.). Thus, the decrease in weed diversity has dramatically affected the associated food web. Weed species are adapted to crops and to management techniques such as soil disturbance by tillage or ploughing. However, condensation in the last decades with chemical fertilization, use of herbicides, plantations of high-tolerant cereal varieties and use of seed-cleaning mechanisms have decreased species richness (Roschewitz et al., 2005Roschewitz I. et al. The effects of landscape complexity on arable weed species diversity in organic and conventional farming. J Appl Ecol. 2005;42:873-82. ). To assess the true measure of these intensification factors, recent studies have been conducted in different countries to contrast weed flora structure with those of former studies conducted decades ago, e.g., in Germany (Sutcliffe and Kay, 2000Sutcliffe O.L., Kay Q.O.N. Changes in the arable flora of central southern England since the 1960. Biol Conserv. 2000;93:1-8. ), United Kingdom (Lososova et al., 2004Lososova Z. et al. Weed vegetation of arable land in Central Europe: gradients of diversity and species composition. J Veg Sci. 2004;15:415-22. ) the Czech Republic (Pysek et al., 2005Pysek P. et al. Effects of abiotic factors on species richness and cover in Central European weed communities. Agric Ecosyst Environ. 2005;109:1-8. ), and Denmark (Andreasen and Stryhn, 2008Andreasen C., Stryhn H. Increasing weed flora in Danish arable fields and its importance for biodiversity. Weed Res. 2008;48:1-9. ).
Egypt has an area of about one million km2; its cultivated land occupies only four percent and the rest of the country is a desert. The Fayoum region is located about 95 km southwest of Cairo and is considered as one of the oldest agricultural cities in the world, as it was founded around 4000 BC; its location next to the Nile Valley was the main reason to attract extensive human activities, especially agriculture, since the Paleolithic era (Caton-Thompson and Gardner, 1929Caton-Thompson G, Gardner E.W. Recent work on the problem of Lake Moeris. Geograph J. 1929;20-60. ; Mc Donald, 2009Mc Donald M.M.A. Increased Sedentism in the Central Oases of the Egyptian Western Desert in the Early to Mid-Holocene: Evidences from the peripheries. Afr Arch Rev. 2009;26:3-43.; Hamdan and Lucarini, 2013Hamdan M. A., Lucarini G. Holocene paleoenvironmental, paleoclimatic and geoarchaeological significance of the Sheikh El-Obeiyid area (Farafra Oasis, Egypt). Quat Int. 2013;302:154-68.; Fadl, 2016Fadl M.A. Plant remains from the Holocene of Sheikh El-Obeiyid Area (Farafra Oasis, Egypt), 7730-5360 b.p. Int Res J Biol Sci. 2016;5(9):22-31.). It obtains its irrigation water from the Nile and its soil is mainly Nilotic silt. It gathers the characteristics of a desert depression with no outlet to the sea and the characteristics of the Nile Valley. Although it has been one of the most fertile and productive areas in Egypt since ancient times, currently there are no publications available on weed flora of the study area. In the meantime, there have been significant changes in kinds of crop that are typically mature in this area, as well as changes in tillage methods, fertilizer application and weed control methods. The content developed in this work represents an original approach whose aim is to determine the weed flora and its distribution through different habitats in the Fayoum region.
MATERIAL AND METHODS
Study area
Fayoum is a depression in the Libyan Desert, attached to the main valley trunk by a narrow neck-like connection. It has an area of approximately 1,700 km2, and located about 95 km southwest of Cairo. It represents a lateral bud while the Delta is the flower and the Valley is the stem of a Lotus plant (Figure 1). It extends between longitudes 30o23' and 31o5' E, and latitudes 29o5' and 29o35’N with mean annual temperature of 20.9 ºC and mean annual rainfall of 7 mm.
Floristic study
The agroecosystem in the study area (all the area of Fayoum governorate) was divided into 8 habitats (old cultivated land (healthy land), new reclaimed land, salt affected soil, wasteland, roadside, orchards, outskirts and Canal bank). Field data on the floristic composition were gathered throughout intensive fieldwork between January 2013 and May 2015 along the study area. A total of 208 permanently visited stands were surveyed, using a stratified sampling technique, and distributed along different habitats. Stands were determined as follows: 88 stands for old cultivated land, 20 stands for new reclaimed land, 14 for salt affected soil, 14 for wasteland, 20 for roadside, 20 for orchards (mainly orange and lemon orchards), 12 stands for outskirts and 20 stands for canal banks. The size of the stand varied from one site to another, depending on the total cultivated area, variability in both croplands, and habitats. Plant specimens were collected, identified and deposited at the herbarium of the Botany Department, Faculty of Science at Fayoum University. Identifications were performed according to TÓckholm (1974Täckholm V. Student’s Flora of Egypt. 2nd. ed. Cairo: University Publishing Cooperative Printing Company, 1974.) and Boulos (1999Boulos L. Flora of Egypt: Azollaceae-Oxalidaceae. Cairo: Al Hadara Publishing, 1999 v.1, 2000Boulos L. Flora of Egypt: Geraniaceae-Boraginaceae. Cairo: Al Hadara Publishing, 2000. v.2, 2002Boulos L. Flora of Egypt: Verbenaceae-Compositae. Cairo: Al Hadara Publishing, 2002. v.3., 2005Boulos L. Flora of Egypt: Alismataceae-Orchidaceae. Cairo: Al Hadara Publishin, 2005. v.4). Life forms of species were detected while relying on the location of the regenerative buds and the shed parts during the unfavorable season (Raunkiaer, 1934Raunkiaer C. Life forms of plants and statistical geography. Oxford: 1934.) while the chorotypes were determined according to Zohary (1973Zohary M. Geobotanical foundations of the Middle East. Stuttgart: Gustav Fischer Verlag, 1973. 2v.).
Statistical analysis
We assessed floristic similarities between different habitats by performing a hierarchical classification analysis based on incidence interpolated data with Wards’s (minimum variance) procedure and Euclidean distances as a dissimilarity measure (Ward, 1963Ward J.H. Hierarchical grouping to optimize an objective function. Am Stat Assoc J. 1963;58:236-44. ); this analysis was performed with Statistica ver. 8 (StatSoft, Inc., Tulsa, OK, USA). Jaccard’s similarity index was applied to evaluate ß diversity similarity among stands based on presence/absence of the species, as follows: JI=a/(a+b+c); a: number of common species in samples, b: species that exist just in the first sample, c: number of species that exist only in the second sample.
RESULTS AND DISCUSSION
One hundred and seventy-five species of vascular plants belonging to 124 genera and 35 families were recorded (Table 1). The richest families were Poaceae, Asteraceae (Compositae) and Fabaceae (Leguminoseae), whereas 10 families were recorded as monospecies and accounted for less than 29% of the total recorded families. Generally, family size was small; 33 families have less than 10 species and only four families have more than 10 species. Genera with the highest number of species were Euphorbia (6 species), Amaranthus and Cyperus (5 species each) and Suaeda (4 species). Cynodon dactylon and Alhagi graecorum were shown to be ubiquitous species as they were were recorded in all habitats while Tamarix nilotica and Phragmites australis occupied 87% of the study habitats. Twenty percent of the total species were recorded in one habitat only; about 70% of these species were recorded in old cultivated land and/or orchards while no species was confined to new reclaimed land or roadside habitats (Table 1). Old cultivated lands contained the highest number of species, genera and family numbers (85%, 89% and 94% respectively), followed by orchard habitats (58%, 60% and 71%, respectively). By contrast, wasteland and canal bank habitats recorded the lowest numbers (Figure 2). Therophytes were the dominant life form (98 species) while Hemicryptophytes recorded the second most frequent life form (39 species) while Chamaephytes and Geophytes presented 15 and 14 species, respectively. Phanerophytes were the smallest group in this study, 5% (Figure 3). Table 2 shows the different chorotypes of the surveyed flora. Cosmopolitan was represented by 25 species with high occurrence; Palaeotropical, by 18 species; Pantropical, by 16 species and Plurireginal, by 6 species in the study region. Monoregional was represented by about 19% with Saharo-Arabian as the most common chorotype (represented by 11 species). Biregional was represented by 43 species with the highest representation of Mediterranean and Saharo-Sindian by 24%. The triregional chorology was represented by 17%. The highest Jaccard similarity index was recorded between old cultivated land (healthy land) and orchard habitats while the lowest one was found between wasteland and roadside (Table 3). Canal bank habitats showed the lowest similarity indices in comparison with other habitats. The dendrogram obtained from the hierarchical classification (Figure 4) supported Jaccard similarity results; it clustered habitats into two main groups: the first one included two habitats: old cultivated lands and orchard. The other main group was subdivided into three subgroups, and each of them contained two homogeneous habitats; new reclaimeded land with wasteland, roadside with canal bank and salt affected soil with outskirt habitats.
List of plant species recorded in the study area with their families and life forms in different habitats (+: present, -: absent)
Hierarchical classification of the different habitats based on their floristic composition (incidence data), using Ward’s method and Euclidean distances as measures of Linkage Distance.
Diversified crop rotations in recent years has increased weed diversity compared with monocultures (Doucet et al., 1999Doucet C. et al. Separating the effects of crop rotation from weed management on weed density and diversity. Weed Sci. 1999;47:729-35.). Poaceae, Fabaceae (Leguminosae) and Compositeae; the richest families, in the current study, represent the most common ones in the Mediterranean North African flora (Quézel, 1978Quézel P. Analysis of the flora of Mediterranean and Saharan Africa. Ann Molec Bot Gard. 1978;65:479-534. ), and they are considered to be the most important families in small-scale farming in highland Peru, central Mexico and northern Zambia (Vibrans, 1998Vibrans H. Native maize field weed communities in south-central Mexico. Weed Res. 1998;38:153-66.). Poaceae recorded the highest number of species because of its ability to grow in various habitats. Boulos and Fahmy (2007Boulos L., Fahmy G. Grasses in ancient Egypt. Kew Bull. 2007;62:507-11.) recorded that grasses in Egypt grow in many different ecosystems: salt marshes and arid lands, for example, and they are especially prevalent in old cultivated lands in the Nile Valley. The wide distribution of the some weeds in the current study may be interpreted as species with wide ecological amplitude and characterized by phenotypic plasticity and heterogeneity (Shaltout and Sharaf El-Din, 1988Shaltout K.H., Sharaf El-Din A. Habitat types and plant communities along transect in the Nile Delta region. Feddes Repert. 1988;99:159-62.; Abd El-Ghani et al., 2013Abd El-Ghani M.M. et al. Weed flora in the new reclaimeded lands along the northern sector of the Nile Valley in Egypt. Turk J Bot. 2013;37:464-88. ). Restricted distribution of other weeds can be attributed to the habitat preference phenomenon, e.g., hydrophytic plants Ludwigia stolonifera and Cyperus alopecuroides. Old cultivated lands contained the highest number of species, followed by orchard habitats, because these habitats provide weed species with suitable conditions for germination, growth and reproduction. By contrast, road side and wasteland habitats recorded the lowest number of species as a result of the lack of water and compacted soil, respectively.
Life form reported in the present study supports many previous studies in Egyptian agroecosystem habitat (Abd El-Ghani, 1994Abd El-Ghani M.M. Weed plant communities of orchards in Siwa Oasis, Egypt. Feddes Repert. 1994;105:387-98.; Shaheen, 2002Shaheen A.M. Weed diversity of newly farmed land on the southern border of Egypt (Eastern and Western shores of Lake Nasser). Pak J Biol Sci. 2002;5:602-8.). Weed communities were characterized by being mostly therophytes with short stature (shorter than the crop), which flowered between March and April and had low seed mass (Storkey et al., 2010Storkey J., Moss S.R., Cussans J.W. Using assembly theory to explain changes in a weed flora in response to agricultural intensification. Weed Sci. 2010;58:39-46. ). The low number of phanerophytes might be related to the intense handling used in the plantations, such as ploughing, subsoiling, harrowing, levelling, and furrowing operations, which could affect the life cycles of phanerophytes.
Abd El-Ghani (1994Abd El-Ghani M.M. Weed plant communities of orchards in Siwa Oasis, Egypt. Feddes Repert. 1994;105:387-98.) recorded similar results concerning the weed flora of the Siwa Oasis orchards and reported that this may indicate severe human impact on the study area. The Mediterranean floristic elements extending in the Euro-Siberian territory attained higher representation as compared with the Mediterranean species with the Saharo-Sindian extension. These results agree with the findings that suggest the presence of a transitional Mediterranean territory in Egypt between the pure Mediterranean and the Saharo-Arabian territory (El-Demerdash et al., 1997El-Demerdash M.A., Hosni H.A., Al-Ashri N. Distribution of the weed communities in the North East Nile Delta, Egypt. Feddes Repert. 1997;108:219-32.). The widely distributed species belong to bi- and tri-regional chorotypes and constituted 73 species, thus revealing that the floristic structure of the study area is relatively complex as compared with other areas of Egypt.
Similar results were reported in other areas all over the country (Abd El-Ghani, (1992Abd El-Ghani M.M. Flora and vegetation of Qara Oasis, Egypt. Phytocoenologia. 1992;21:1-14.) in Qara Oasis, Abd El-Ghani and Fahmy, (1998Abd El-Ghani M.M., Fahmy A.G. Composition of and changes in the spontaneous flora of Feiran Oasis, S Sinai, Egypt, in the last 60 years. Willdenowia. 1998;28:123-34. ) in Feiran Oasis, Shaheen, (2002Shaheen A.M. Weed diversity of newly farmed land on the southern border of Egypt (Eastern and Western shores of Lake Nasser). Pak J Biol Sci. 2002;5:602-8.) in Upper Egypt and Abd El- Ghani and Fawzy, (2006Abd El-Ghani M.M., Fawzy A.M. Plant diversity around springs and wells in five oases of the western desert, Egypt. Int J Agric Biol. 2006;8:249-55.) in the Egyptian Oases).
The shade effect produced by large trees in orchards keeps the soils moist for longer; at the same time, farmers cultivate some crops such as Egyptian clover in orchards in the winter, which created many similar characters between these habitats and led to the Ward classification whereby these habitats are clustered in one group.
The results provide the most up-to-date information on weed flora for one of the oldest agronomic cities in the world and its distribution through different habitats. They are considered to be valuable as a grounding for political decisions concerning the management of arable land.
REFERENCES
- Abd El-Ghani M.M. Flora and vegetation of Qara Oasis, Egypt. Phytocoenologia. 1992;21:1-14.
- Abd El-Ghani M.M. Weed plant communities of orchards in Siwa Oasis, Egypt. Feddes Repert. 1994;105:387-98.
- Abd El-Ghani M.M., Fahmy A.G. Composition of and changes in the spontaneous flora of Feiran Oasis, S Sinai, Egypt, in the last 60 years. Willdenowia. 1998;28:123-34.
- Abd El-Ghani M.M., Fawzy A.M. Plant diversity around springs and wells in five oases of the western desert, Egypt. Int J Agric Biol. 2006;8:249-55.
- Abd El-Ghani M.M. et al. Weed flora in the new reclaimeded lands along the northern sector of the Nile Valley in Egypt. Turk J Bot. 2013;37:464-88.
- Al-Sherif E. Melilotus indicus (L.) All., a salt-tolerant wild leguminous herb with high potential for use as a forage crop in salt-affected soils. Flora. 2009;204:737-46.
- Al-Sherif, E., Hegazy, A.K., Gomaa, N.H., Hassan, M.O. Allelopathic effect of black mustard tissues and root exudates on some crops and weeds. Planta Daninha. 2013;31(1):11- 9.
- Andreasen C., Stryhn H. Increasing weed flora in Danish arable fields and its importance for biodiversity. Weed Res. 2008;48:1-9.
- Boulos L. Flora of Egypt: Azollaceae-Oxalidaceae. Cairo: Al Hadara Publishing, 1999 v.1
- Boulos L. Flora of Egypt: Geraniaceae-Boraginaceae. Cairo: Al Hadara Publishing, 2000. v.2
- Boulos L. Flora of Egypt: Verbenaceae-Compositae. Cairo: Al Hadara Publishing, 2002. v.3.
- Boulos L. Flora of Egypt: Alismataceae-Orchidaceae. Cairo: Al Hadara Publishin, 2005. v.4
- Boulos L., Fahmy G. Grasses in ancient Egypt. Kew Bull. 2007;62:507-11.
- Caton-Thompson G, Gardner E.W. Recent work on the problem of Lake Moeris. Geograph J. 1929;20-60.
- Doucet C. et al. Separating the effects of crop rotation from weed management on weed density and diversity. Weed Sci. 1999;47:729-35.
- El-Demerdash M.A., Hosni H.A., Al-Ashri N. Distribution of the weed communities in the North East Nile Delta, Egypt. Feddes Repert. 1997;108:219-32.
- Fadl M.A. Plant remains from the Holocene of Sheikh El-Obeiyid Area (Farafra Oasis, Egypt), 7730-5360 b.p. Int Res J Biol Sci. 2016;5(9):22-31.
- Hamdan M. A., Lucarini G. Holocene paleoenvironmental, paleoclimatic and geoarchaeological significance of the Sheikh El-Obeiyid area (Farafra Oasis, Egypt). Quat Int. 2013;302:154-68.
- Lososova Z. et al. Weed vegetation of arable land in Central Europe: gradients of diversity and species composition. J Veg Sci. 2004;15:415-22.
- Mc Donald M.M.A. Increased Sedentism in the Central Oases of the Egyptian Western Desert in the Early to Mid-Holocene: Evidences from the peripheries. Afr Arch Rev. 2009;26:3-43.
- Pysek P. et al. Effects of abiotic factors on species richness and cover in Central European weed communities. Agric Ecosyst Environ. 2005;109:1-8.
- Quézel P. Analysis of the flora of Mediterranean and Saharan Africa. Ann Molec Bot Gard. 1978;65:479-534.
- Raunkiaer C. Life forms of plants and statistical geography. Oxford: 1934.
- Roschewitz I. et al. The effects of landscape complexity on arable weed species diversity in organic and conventional farming. J Appl Ecol. 2005;42:873-82.
- Shaheen A.M. Weed diversity of newly farmed land on the southern border of Egypt (Eastern and Western shores of Lake Nasser). Pak J Biol Sci. 2002;5:602-8.
- Shaltout K.H., Sharaf El-Din A. Habitat types and plant communities along transect in the Nile Delta region. Feddes Repert. 1988;99:159-62.
- Storkey J., Moss S.R., Cussans J.W. Using assembly theory to explain changes in a weed flora in response to agricultural intensification. Weed Sci. 2010;58:39-46.
- Storkey J., Westbury D.B. Managing arable weeds for biodiversity. Pest Manag. Sci. 2007;63:517-23.
- Sutcliffe O.L., Kay Q.O.N. Changes in the arable flora of central southern England since the 1960. Biol Conserv. 2000;93:1-8.
- Täckholm V. Student’s Flora of Egypt. 2nd. ed. Cairo: University Publishing Cooperative Printing Company, 1974.
- Trezzi M.M. et al. Allelopathy: driving mechanisms governing its activity in agriculture. J Plant Interact. 2016;11:53-60.
- Vencill W. Herbicide handbook. Lawrence: Weed Science Society of America, 2002. 493p.
- Vibrans H. Native maize field weed communities in south-central Mexico. Weed Res. 1998;38:153-66.
- Wang S. et al. UV-B radiation increases paraquat tolerance of two broad-leaved and two grass weeds in relation to changes in herbicide absorption and photosynthesis. Weed Res. 2007;47:122-8.
- Ward J.H. Hierarchical grouping to optimize an objective function. Am Stat Assoc J. 1963;58:236-44.
- Zohary M. Geobotanical foundations of the Middle East. Stuttgart: Gustav Fischer Verlag, 1973. 2v.
Publication Dates
-
Publication in this collection
2018
History
-
Received
14 Nov 2016 -
Accepted
16 Mar 2017
