Osun Sacred Forest Grove is a unique landscape that combines important environmental, biological and cultural features. We conducted a multifaceted rapid assessment to evaluate the conservation status of the grove eleven years after it was designated a World Heritage Site. We recorded a rich diversity, consisting of 2 rock types, 3 minerals, 88 plant species, 108 insect families and 4 mammal species. Our survey also enabled us document up to 40 cultural artifacts. However, the plants, small mammals and insects collected, in their role as indicator taxa, demonstrate that biodiversity decreases extending outward from the core area of the grove into the buffer and outside zones. In addition, the detection of heterotrophic bacteria and fungi from microbiological analyses in water samples of the Osun River which runs through the grove raises health concerns. Our findings lead us to recommend that efforts be stepped up to deter encroachment of the buffer and outside zones into the core area of the grove. Furthermore, careful repair of deteriorating cultural artifacts should be undertaken regularly, with the actions of visitors monitored adequately to prevent depletion of biodiversity and pollution of the environment.
From ancient times sacred groves, invoking religious and ethnic ideals have represented an alternate but effective means of conserving biodiversity. In modern times, these traditional efforts at conservation are becoming increasingly reinforced by legislative and governmental frameworks. These groves are usually rich patches of undisturbed forest, serving as a natural habitat for endemic, rare, primitive and economically valuable organisms (Lyngwi & Joshi, 2015) . Results of a comparative study have also shown that sacred groves shelter high diversity of medicinal plants and have more vigorous regeneration of trees than formal forest reserves (Baraiah et al., 2003) . Therefore inventories are desirable to assess the diversity present in these groves.
Nevertheless, most surveys of forest biodiversity in south-western Nigeria have targeted singular taxa (e.g., Ogunjemite & Olaniyi, 2012 ; for Chimpanzees in Oluwa Forest Reserve) or a particular segment of the biota ( Aigbe & Omokhua, 2015 ; on trees in Oban Forest Reserve). Biodiversity is interactive, with varied taxa influencing and depending on each other. Insects pollinate plants and serve as prey to rodents and birds, which in turn help to disperse seeds. In addition, non-biological components of the environment (physical and even cultural aspects) affect the well-being of biota. For instance, the integrity and freshness of streams and rivers (i.e., the physical environment) affect their capacity to serve as a substrate and habitat for aquatic organisms, while taboos within certain ethnic groups (the cultural environment) have actually played a positive role in preserving certain forest species such as primates in Indonesia (Riley, 2010) .
As elements of the environment and biodiversity are interconnected, so also can the measurement of certain aspects provide information about others. For example, detecting Coliform bacteria or sampling arthropods such as Odonata which are closely associated with aquatic habitats provide information about water quality (Caro & Doherty, 1999; Convention on Biological Diversity, 2006) . In another instance, comparing small mammal assemblages has helped track how the derived savanna is encroaching into forests in south-western Nigeria (Olayemi & Akinpelu, 2008) . Also, the study of relationships between rock composition and floral and faunal diversity has helped to reveal the association of mosquitoes with rock holes in the Okeiho-Iseyin area of southwestern Nigeria (Ayansola et al., 2003) .
The Osun Sacred Forest Grove represents a classic example of where important biological, environmental and cultural values converge to form a special landscape in need of carefully considered conservation. Historically, the Osun River, which runs through Osogbo town, circumscribes the forest grove which the indigenes hold sacred. Hunting of animals and fishing within the river is prohibited by ethnic taboo. In addition, around August every year, the Osun Festival is held in honour of the river goddess, attracting thousands of worshippers and tourists to the grove. From 1960 into the 2000s the Austrian artist, Suzanne Wenger, erected a series of sculptures embedded across the terrain of the grove with motifs in Yoruba traditional myth and religion that enhanced its value as a cultural site of key significance within Osogbo and indeed Nigeria. Ultimately, in 2005, the United Nations Scientific and Cultural Organization (UNESCO) designated the Osun Forest Grove a World Heritage Site.
However, several factors currently threaten the cultural and natural sanctity of Osogbo Sacred Grove. For instance, over the years, Osogbo town has expanded to surround the grove and the pressures of urban development appear to infringe the protected area. Also, there is no information concerning the effect the constant stream of visitors through the year (for spiritual activities and tourism) may have on the grove. There is an urgent need to obtain contemporary data concerning physical, biological and cultural aspects of this protected area.
Therefore it was our aim to conduct a rapid environmental assessment of Osun Sacred Grove in order to provide updated information about its conservation status. More specifically, our objectives were: 1) to plot a digitized map against which key biota and cultural features in the protected area can be referenced; 2) to sample, as indicator taxa, higher and lower plants, arthropods, small mammals and primates; and 3) to determine the water quality of the Osun River in the grove by measuring various physical and microbiological parameters. These results are presented in relation to anthropological threats noticed in the protected area during our sampling.
Osun Sacred Grove is located approximately between latitudes 7˚44'50.0'' - 7˚46'00.0'' N and longitudes 4˚32'40'' - 4˚33'40'' E (
The buffer zone around the grove features significant anthropogenic influence. It is majorly farmland, cultivated mostly with subsistence crops like maize, beans, cassava, okra and pineapple. Within the buffer zone northward of the Main Gate (
As the vegetation from the buffer zone was predominantly agricultural, only plants from the core zone of the grove were surveyed. Voucher specimens were identified, preserved and deposited in Herbarium of Natural History Museum (UNIFEM), Obafemi Awolowo University, Ile-Ife, Nigeria. Identification was made using herbarium specimens, monograms and available Floras. Tour guides employed at the grove were also interviewed for the medicinal uses of some of the plants collected.
Insects were sampled in the core, buffer and outside zones. They were collected by both direct and indirect methods. The direct methods used in this study include searching and hand picking, sweep and butterfly netting. The indirect methods were with malaise traps, berlese traps, yellow pan traps, light traps and pit fall traps. Insect specimens collected were preserved by wet and dry preservation methods. Dry-preserved specimens were sacrificed with ethyl acetate, dried properly and identified before being stored in insect boxes and cabinets.
Murid rodents, shrews and primates were the mammals surveyed in this study. As collecting vertebrates is prohibited within the grove, small mammals were captured using Sherman traps in the buffer and outside zones. Traps were set in the late afternoon until the morning of the next day. Sighting of primates was carried out while
walking through designated transects that covered most of the core area. Transects were patrolled periodically from early in the morning till late afternoon. The transects, demarcated by taking advantage of the siting of cultural artifacts as represented by points in
Preliminary survey of the rock types was carried out within the Osun Sacred grove. As Osun River strips away the soil it exposes the underlying bedrock, which gives the opportunity to survey the underlying rock types and minerals along the river course.
In order to assess water quality within the grove a total of 8 samples were collected between 9.00 - 11.00 am daily from different locations within the core zone (L1-L8;
In accordance with APHA (1998) Heterotrophic Plate Count (HPC) was used to measure bacteriological quality of water samples. Hundredfold serial dilution of each water sample was carried out six times in a set of test-tubes containing 9.9 ml sterile water. 1 ml of each dilution was plated out in duplicates, employing the use of nutrient agar medium. These were kept in molten form. Pour Plate method was adopted. The culture plates were incubated invertedly and aerobically at 35˚C for 48 hours. The plates were observed for growth and selected for count after expiration of the incubational period. The number of colonies with less 300 and its duplicate for each sample was selected. The count so obtained was multiplied by the dilution factor and expressed as colony forming unit (CFU) ml−1 of the original sample.
The same procedure for the Heterotrophic Plate Count (HPC) was repeated for the fungi count. In this method malt extract agar was employed as the culture medium following APHA (1998) . The culture plates were incubated invertedly and aerobically at 30˚C for 7 days (until the plates showed no further increase in the number of fungal colonies).
Coliform tests were also carried out on the water samples. The most probable number (MPN) of coliform presumptive test was carried out on each of the test samples. The culture tubes were incubated at 35˚C for 48 hours. After incubation, the numbers of coliform cells present in 100 ml of the original water sample were estimated. Furthermore, confirmatory test was carried out on the water samples for detection of Escherichia coli. Tubes showing gas and/or acid (MPN) were sub-cultured on Eosin Methylene blue (EMB) agar incubated at 35˚C for 24 hours. The tubes were observed for typical colonies of E. coli. Several typical colonies of E. coli from the EMB plate were sub-cultured into brilliant green broth fermentation tubes and peptone water. The fermentation tubes were incubated at 37˚C and 44˚C for 48 hours while that of the peptone water was incubated at 35˚C for 24 hours.
We also carried out an inventory of artifacts of cultural significance such as shrines and sculptures as they are laid out within the natural habitat of the grove. The relative position for each of these artifacts was recorded in GPS coordinates and plotted on a digital map (
As a tropical forest, the vegetation of Osun Sacred Grove is of three layers. The first consisting of herbs, small shrubs and tree seedlings; the second consists of average-height trees and shrubs; the topmost consists of very tall trees of 15-30 m in height with various girths and with climbers forming a dense or partially dense canopy. The plant species and their families identified during the survey comprise of 74 species of Angiosperm (41 families), 10 species of Pteridophytes (5 families), 2 species of Bryophytes (2 families), and 2 species of lichens (2 families) as shown in
Botanical Name of Plants | Family | Habit/Growth form | Common Name | Local Name |
---|---|---|---|---|
Angiosperms | ||||
1) Acanthospermun hispidum | Asteraceae | Herb | ||
2) Acanthus montanus (Nees) T. Anders | Acanthaceae | Herb | False thistle | Ahonekun |
3) Adeniacissampeloides | Passifloraceae | Tree | Arokeke | |
4) Ageratum conyzoides L. | Asteraceae | Herb | Imiesu | |
5) Albizia zygia (DCJ.) F. Macbr. | Mimosaceae | Tree | ||
6) Alternanthera pungens H.B.K. | Amaranthaceae | Herb | ||
7) Alfzelia africana Sm | Ceasalpiniaceae | Tree | Apa | |
8) Alchornea laxiflora (Benth) Pas & Hoffin | Euphorbiaceae | Shrub | ||
9) Allophyllus africanus P. Beauv. | Tree | Eekanehoro | ||
10) Anchomanes difformis Engl. | Araceae | Herb | OgiriIsako | |
11) Alstonia boneii De Wild | Apocynaceae | Tree | Ahun | |
12) Andropogon tectorum Shum & Thorn | Poaceae | Grass | ||
13) Antiaris toxicaria Lesch. | Moraceae | Tree | Oro | |
14) Annona seleganensis | Annonaceae | Tree | ||
15) Aristolochia ringes Vahl | Ariostolochiaceae | Climber | ||
16) Aspilia Africana (Pers) C.D.Adams | Apocynaceae | Herb | ||
17) Bambusa vulgaris Schrad. ex J.C. Wendl | Poaceae | Bamboo | Oparun | |
18) Baphia nitida Lodd | Papilionaceae | Tree | Irosun | |
19) Blepharis maderaspertensis | Asteraceae | Herb | Ojusaju | |
20) Blighia sapida Loveth. | Sapindaceae | Tree | Isin | |
21) Brachystegia eurycoma Harms | Caesalpiniaceae | Ako | ||
22) Bridelia micrantha (Hoschst) Baill. | Euphorbiaceae | Tree | Ire | |
23) Cactus feruginea | Cornaraceae | Herb | ||
24) Carpolobia lutea (G. Don) | Polygalaceae | Shrub | Osunsun | |
25) Chasmanthera dependes Hochst. | Menispermaceae | Tree | ||
26) Chrysophyllum albidum G. don | Sapotaceae | Tree | Agbalumo | |
27) Ceiba petandra (L.) Gaertn | Bombaceae | Tree | Araba | |
28) Celtiszenkeri Engel. | Ulmaceae | Tree | Ita | |
29) Centrosema pubescens Benth | Papilionaceae | Climber | EwuAhun | |
30) Chromolaena odoratum (L.) | Asteraceae | Herb | Akintola | |
31) Cissus petiolata Hook. | Vitaceae | Climber | ||
32) Cnestis ferruginea D.C. | Comaraceae | |||
33) Cola milleni K.Shcum | Sterculaceae | Tree | Obi edun |
34) Combretum bracteatum Engl. & Diels | Combretaceae | Liane | Ogandudu | |
---|---|---|---|---|
35) Comberum platypterum Hutch. &Dalz. | Combretaceae | Liane | Ogandudu | |
36) Commelina diffusa Burm. | Commelinaceae | Herb | ||
37) Crotalaria retusa L. | Fabaceae | Shrub | Rattle weed | |
38) Delonix regia (Boj ex Hook) | Fabaceae | Tree | Flamboyant | Sekeseke |
39) Drycaena fragrans (L.) Ker Gawl. | Asparagaceae | Tree | Peregun | |
40) Elaeis guineensis Jacq. | Asteraceae | Tree | Ope | |
41) Euphorbia hirta L. | Euphorbiaceae | Herb | Asthma plant | |
42) Euphorbia heterophylla L. | Euphorbiaceae | Herb | ||
43) Ficus exasperata Vahl. | Moraceae | Tree | Sand paper tree | Eepin/ipin |
44) Funtumia elastica (Preuss) Stapf. | Apocynaceae | Tree | ||
45) Gliricidia sepium Jacq. | Papilionaceae | Tree | Agunmaniye | |
46) Grewia mollis Juss | Tiliaceae | Tree | Ora-igbo | |
47) Grewia capinifolia Juss | Malvaceae | Tree | Itakunokere | |
48) Gomphrena celosoides Mart. | Amaranthaceae | Herb | Irawoile | |
49) Gmelina arborea Rosb. | Verbanaceae | Tree | ||
50) Icacina trichantha Oliv. | Icacinaceae | Shrub | Gbegbe | |
51) Jatropha curcas L. | Euphorbiaceae | Shrub | ||
52) Jatropha podagrica L. | Euphorbiaceae | Shrub | ||
53) Lannea welwitschii (Hien) Engler | Anarcadiaceae | Tree | Opon | |
54) Lecamniodiscus cuscupaniode Planch ex Bth. | Sapindaceae | Tree | Akika | |
55) Lonchocarpus cyanescens Benth | Fabaceae | Shrub | Elu | |
56) Napoleona vogelii Hook & Planch | Lecythidaceae | Tree | Ito | |
57) Newboudia laevis (P. Beauv) Seem. ex Bur. | Bignonaceae | Tree | Akoko | |
58) Milicia excelsa (Welw) C. C. Berg | Moraceae | Tree | Iroko | |
59) Morinda lucida Benth. | Rubiaceae | Tree | Oruwo | |
60) Mormodica charantia L. | Curcubitaceae | Herb | Bitter melon | Ejinrin |
61) Myrianthus arboreus P. Beauv | Moraceae | Tree | ||
62) Nerium oleander L. | Apocynaceae | Shrub | Oleander | |
63) Olax subscorpioidea Oliv. | Olaeceae | Shrub | Ifon | |
64) Pterocarpus osun Craib | Fabaceae | Tree | ||
65) Rauvolfia vomitora Afzel | Apocynaceae | Tree | Asofeyeje | |
66) Sansieviera liberica Gerome & Labroy | Liliaceae | Shrub | OjaIkoko | |
67) Spigelia anthelmia L. | Euphorbiaceae | Herb | Pink weed | |
68) Spondias mombin L. | Anarcadiaceae | Tree | Iyeye |
69) Synedrella nodiflora Gaertn | Asteraceae | Herb | Starwart | |
---|---|---|---|---|
70) Tectona grandis L. | Verbanaceae | Tree | ||
71) Tithonia diversifolia (Hemsl.) A. Gray) | Asteraceae | Tree | ||
72) Tridax procumbens L. | Asteraceae | Herb | ||
73) Triplochiton scleroxylon K. Schum. | Sterculaceae | Tree | Arere | |
74) Zanthoxylum xanthoxyloides (Lam.) | Rutaceaea | Tree | Ata | |
Pteridophytes | ||||
1) Asplenium trichomanes L. | Aspleniaceae | |||
2) Dryopteris nicklesii Turd | Aspleniaceae | |||
3) Cyclosorus afer (Christ) Ching | Dryopteridaceae | |||
4) Nephrolepis biserrata (Sw.) Schott | Thylepteridaceae | |||
5) Nephrolepis undulate Afzelius ex. Sw | Dryopteridaceae | |||
6) Pityrogramma calomelanos L. | Dryopteridaceae | |||
7) Platycerium stemaria (P. Beauv) Desv | Polypodiaceae | |||
8) Pteris togoensis Hieron | Pteridaceae | |||
9) Pteris mildbraedii L. | Pteridaceae | |||
10) Pteris artrovirens Bak. | Pteridaceae | |||
Bryophytes | ||||
1) Racopilum africanum Mitt. | Racopilaceae | |||
2) (unidentified*) | ||||
Lichens | ||||
1) Hypogymnia physodes (L) Nyl | Paemeliaceae | Foliose | ||
2) Lepraria incana | Stereocaulaceae | Leprose | Dust lichen |
The lower number of plant species recorded in this study could be due to the fact that our sampling was within a limited period that is typical of rapid assessment schemes. Still, our survey reveals a range of plant diversity that is worth preserving, especially those identified to possess medicinal and other ethno-botanical properties (
To our knowledge there has been no definite and comprehensive information to date published on the biodiversity and abundance of insects in Osun Sacred grove. One hundred and eight insect families belonging to 17 different orders of insects were recorded during this study (
Name of Plants | Local names | Medicinal uses |
---|---|---|
Alchornea laxiflora | Pepe, Ijan | Leaves for pile; roots boiled as blood tonic |
Dracaena fragrans | Peregun | Leaves for high fever |
Cola milleni | Obi edun | Boosting sperm cells |
Mormordica charantia | Ejinrin | Leaves for pile, stomachache |
Morinda lucida | Oruwo | Leaves as antimalarial |
Lonchocarpus cyanescens | Elu | For treating pile; also for treating yaws, leprosy and skin diseases. |
Ceiba petandra | Araba | Reliefs of Dysmenorrhea |
Grewia carpinnifolia | Itakunokere | Boosting sperm count |
Milicia excelsia | Iroko | Bark as antimalarial |
Rauvolfia vomitora | Asofeyeje | Bark for diabetic and malaria; as sedative and treating menstrual disorder. |
Anchomanes difformis | Ogiriisako | Tubers for treating measles, cough |
Olax subscorpioidea | Ifon | Stem for treating tooth decay |
Zanthoxylum zanthoxyloides | Ata | For treating tooth ache |
The presence of Osun river which runs through the grove could explain the high occurrence of Odonata and Ephemeroptera in core and buffer zones (
Insect family | Core zone | Buffer zone | Outside zone | Insect family | Core zone | Buffer zone | Outside zone |
---|---|---|---|---|---|---|---|
Order Hymenoptera | |||||||
Pergidae | X | X | X | Ichneumonidae | X | X | X |
Siricidae | X | Braconidae | X | ||||
Argidae | X | X | X | Chrysididae | X | ||
Cimbicidae | X | Pelecinidae | X | ||||
Formicidae | X | X | X | Sphecidae | X | ||
Evaniidae | X | X | X | Vespidae | X | X | X |
Aphelenidae | X | X | Tiphiidae | X | |||
Gasteruptiidae | X | X | X | Megachildae | X | X | |
Order Diptera | |||||||
Tipulidae | X | X | X | Asilidae | X | X | X |
Cecidomyiidae | X | Bombyliidae | X | X | |||
Simulidae | X | X | Drosophilidae | X | X | ||
Chironomidae | X | Tephritidae | X | X | X | ||
Culicidae | X | X | X | Muscidae | X | X | X |
Dixidae | X | X | Anthomyiidae | X | X | X | |
Tabanidae | X | X | Calliphoridae | X | X | X | |
Stratiomydae | X | X | X | Sarcophagidae | X | X | |
Order Lepidoptera | |||||||
Papilionidae | X | X | X | Psychidae | X | ||
Satyridae | X | X | X | Sphingidae | X | X | X |
Pieridae | X | X | X | Limacodidae | X | X | X |
Nymphalidae | X | X | X | Saturniidae | X | X | X |
Sesiidae | X | X | Noctuidae | X | |||
Pterophoridae | X | X | Tinneidae | X | X | ||
Pyralidae | X | X | Coleophoridae | X | X | X | |
Order Coleoptera | |||||||
Carabidae | X | X | X | Dermestidae | X | X | X |
Dystiscidae | X | X | Buprestidae | X | X | ||
Gyrinidae | X | X | Tenebrionidae | X | X | ||
Scarabaeidae | X | X | X | Cerambycidae | X | X | |
Silphidae | X | X | X | Bruchidae | X | X | X |
Hydrophilidae | X | X | Chrysomelidae | X | X | X | |
Byturidae | X | X | X | Curculionidae | X | X | X |
Helodidae | X | Anthribidae | X | X | |||
Elateridae | X | X | Brentidae | X |
Order Heteroptera | |||||||
---|---|---|---|---|---|---|---|
Belostomatidae | X | X | Anthocoridae | X | X | ||
Nepidae | X | X | X | Reduviidae | X | X | |
Gelastocoridae | X | Tingidae | X | ||||
Corixidae | X | X | Miridae | X | X | X | |
Notonectidae | X | X | X | Lygaeidae | X | ||
Gerridae | X | X | Pentatomidae | X | X | X | |
Order Homoptera | |||||||
Cicadidae | X | X | X | Aleyrodidae | X | X | X |
Membracidae | X | Aphididae | X | X | |||
Cicadellidae | X | Kerridae | X | ||||
Fulgoridae | X | Coccidae | X | ||||
Issidae | X | X | Pseudococcidae | X | |||
Psyllidae | X | X | X | ||||
Order Isoptera | |||||||
Kalotermitidae | X | X | Termitidae | X | X | X | |
Rhinotermitidae | X | X | |||||
Order Dermaptera | |||||||
Labiidae | X | ||||||
Order Mantodea | |||||||
Mantidae | X | X | X | ||||
Order Blattaria | |||||||
Blattidae | X | X | X | Blattelidae | X | X | |
Order Phasmida | |||||||
Phasmatidae | X | X | X | ||||
Order Orthoptera | |||||||
Acrididae | X | X | X | Tettigoniidae | X | X | X |
Gryllidae | X | X | Gryllotalpidae | X | |||
Tetrigidae | X | X | X | ||||
Order Plecoptera | |||||||
Capniidae | X | X | X | ||||
Orer Zygoptera | |||||||
Coenagrionidae | X | X | |||||
Order Odonata | |||||||
Libellulidae | X | X | Macromiidae | X | |||
Aeshnidae | X | X | |||||
Order Thysanura | |||||||
Lepismatidae | X | ||||||
Order Collembola | |||||||
Sminthuridae | X | X | Isotomidae | X | X | X |
Nine small mammal specimens were captured in the buffer and outside zones (as trapping of mammals is prohibited within the grove). These are made up of 3 species, which are the Multimammate rat Mastomys natalensis, the Pygmy mouse Mus (Nannomys) setulosus and Olivier’s shrew Crocidura olivieri (
Concerning primates, a total of 289 sightings were made within the core zone. All specimens were Mona monkeys Cercopithecus mona, identified based on external morphological features published in Butynski et al. (2013) . This contrasts a previous report by Babalola et al. (2014) that the White throated monkey (Guenon cercopithecus erythrogaster) is the dominant primate within Osun grove. We did not encounter this latter species during this survey.
From
An inventory of the rock types of Osun Osogbo grove reveals that two types occur. These are the Granite gneiss and Granite pegmatite rocks. They outcrop in locality one, Ibu Ojubo (L1,
No. of primates (Cercopithecus mona) sighted | Core Zone | No. of small mammals trapped | Buffer zone | Outside zone | |||
---|---|---|---|---|---|---|---|
Day 1 | Day 2 | Day 3 | Average | ||||
Main gate area | 28 | 8 | 20 | 18.66 | Crocidura olivieri | 2 | 3 |
Main reception area | 41 | 70 | 42 | 51 | Mastomys natalensis | 3 | |
Ojubo Osun area | 17 | 9 | 14 | 13.33 | Mus setulosus | 1 | |
Southern bridge area | 4 | 11 | 25 | 13.33 |
Sampling site | Rock Occurrences | Mineral Occurrences |
---|---|---|
L1 | Granite gneiss (R) | Qtz (F), Fsp (F), and Bt (F) |
L2 | Nil | Qtz (F) |
L3 | Granite pegmatite (R) | Qtz (F), Fsp (F), and Bt (F) |
L4 | Nil | Qtz (F) |
L5 | Nil | Qtz (F) |
L6 | Nil | Qtz (F) |
L7 | Granite gneiss (R) | Qtz (F), Fsp (F), and Bt (F) |
L8 | Nil | Qtz (F) |
*Bt = Biotite, Fsp = Feldspar (orthoclase), Qtz = Quartz, R = Rare and F = Few (Kretz, 1983; Mandarino, 1999; Mandarino and Back, 2004) .
Sampling site | Physical-chemical parameters of water samples | |||
---|---|---|---|---|
PH | Temperature (˚C) | Conductivity (ms/cm) | Total Dissolved Solids (TDS) (ppm) | |
L1 | 7.3 | 27.7 | 0.09 | 068 |
L2 | 7.6 | 27.5 | 0.12 | 106 |
L3 | 7.8 | 26.3 | 0.15 | 110 |
L4 | 7.4 | 25.3 | 0.06 | 054 |
L5 | 6.5 | 31.5 | 0.15 | 104 |
L6 | 7.8 | 26.5 | 0.15 | 145 |
L7 | 7.8 | 25.5 | 0.12 | 098 |
L8 | 7.8 | 26.3 | 0.12 | 106 |
water samples is within the range of 6 to 9 set by World Health Organization (WHO, 2008) for drinking water. This implies that the pH value of the water is suitable for recreational, domestic and agricultural uses. The electrical conductivity of the water samples is between the ranges of 0.06 to 0.15 ms/cm (
The results of the microbiological analysis of the water samples are presented in
Sampling site | THB at 35˚C (CFU/ml) | Coliform Tests | THF at 30˚C (CFU/ml) | ||
---|---|---|---|---|---|
Coli MPN (cells/100ml) | Confirmatory | Completed | |||
L1 | 4.0 × 104 | 2.4 × 102 | ECP* | + | 1.0 × 102 |
L2 | 5.2 × 105 | 1.1 × 103 | ECP | ++ | 3.0 × 102 |
L3 | 3.6 × 105 | 4.6 × 102 | ECP | + | 7.0 × 104 |
L4 | 5.8 × 105 | 36.0 | ECP | + | 4.0 × 102 |
L5 | 3.3 × 105 | 2.1 × 102 | ECNP | NA | 3.0 × 102 |
L6 | 5.0 × 104 | 15.0 | ECNP | NA | 1.4 × 105 |
L7 | 3.3 × 105 | 1.2 × 102 | ECP | + + | 9.0 × 102 |
L8 | 1.14 × 105 | 4.6 × 102 | ECP | + + | 6.0 × 102 |
The number of coliform cells present in the water samples ranged from 15.0 cells/100ml to 1.1 × 103 cells/100ml (
Notably, one of the harmful pathogenic strains, E. coli O157:H7 are known to be found in cow intestines. Escherichia coli O157:H7 produces a powerful toxin that can cause severe illness (Lejeune et al., 2001; Habteselassie et al., 2010) . There is a high tendency that the introduction of faecal coliform into the river is as a result of continuous grazing of cows in the buffer and outside zones of the grove. Escherichia coli O157:H7 have adverse effects on human health, affect animals and contaminates plants by interacting with plants cells especially when the contaminated water is used for agricultural purposes. Consumption of water contaminated with either human or animal faeces can result into urinary tract infections, waterborne disease such as cholera, diarrhea and typhoid according to WHO (2008) . The water can also act as a carrier of other parasitic infections such as balantidias (Balantidium coli) and certain helminths. Furthermore, poliomyelitis (polio) may be contacted if the water is contaminated by the faeces of a person infected by poliovirus. The detection of faecal coliforms in the water samples implies that the water is contaminated and is not safe for drinking or domestic, agricultural and recreational activities without treatment.
The Total Heterotrophic Fungi (TBF) count of the water samples is between the ranges of 1.0 × 102 cfu/ml to 1.4 × 105 cfu/ml (
There are over 40 sculptured images of deities in different postures and undertaking various chores within the sacred grove. There are also several shrines placed in specific areas of the grove, connoting a unity of purpose of the deities. All these allow the grove to be aptly described as a repository of the tangible and intangible cultural heritage of the Osogbo people, a feat that Wenger carried out singularly to protect the sacredness of the grove (Wenger, 1990) .
A map was plotted using coordinates taken on the cultural materials (
From our rapid survey of the Osun Sacred Grove we recorded a significant amount of biological diversity: 88 plant species, 108 insect families and 4 mammal species. We believe further diversity exists that can be uncovered in an extended sampling of the study area. The pattern of distribution of this biological diversity demonstrates the negative, depleting effect that the buffer and outside zones can have if their encroachment upon the core zone of Osun grove is left unchecked. Insects show decreasing diversity extending outward from the core zone. Also, the small mammals captured in the buffer and outside zones are predominantly commensal species associated with human disturbance. Furthermore, from our water sample analyses, heterotrophic bacteria and fungi were detected at various points in the Osun River (specifically in the core zone of the grove). This indicates the presence of feacal contamination (presumably coming from grazing cattle or indeed human waste in the buffer and outsize zones). This presents a danger to conservation and raises health concerns, as the Osun River within the grove is regularly used for bathing and other religious rituals.
Nevertheless, threats to the environmental sanctity of Osun grove appear to come not only from outside but also within. Access to the grove and the behavior of visitors once inside needs to be monitored more closely. For instance, during our sampling we have observed that the road in
The fieldwork was supported by the Centre for Distance Learning, Obafemi Awolowo University. We would also like to acknowledge the assistance of students and all the technical staff in the Natural History Museum, Obafemi Awolowo University, including Adeoba Obadare, Faloba Bakare and Gideon Akinyemi. Kunle Oni helped prepare our digitized map. We thank the staff of the Osun State office of the National Commission for Museums and Monuments for their hospitality and the great lengths they went to facilitate our work.
Adisa Ogunfolakan,Chinyere Nwokeocha,Ayodeji Olayemi,Moshood Olayiwola,Adebola Bamigboye,Adenike Olayungbo,Joan Ogiogwa,Oyeseyi Oyelade,Olanipekun Oyebanjo, (2016) Rapid Ecological and Environmental Assessment of Osun Sacred Forest Grove, Southwestern Nigeria. Open Journal of Forestry,06,243-258. doi: 10.4236/ojf.2016.64020