An inventory of species diversity of insects of the Muni-Pomadze Ramsar site, with special reference to species of conservation concern, was carried out as part of an evaluation of changes in the ecological character of the site, twenty years after designation. Samples were taken from two protected areas within the Ramsar site, in the wet (July), dry (January), and intermediate (June) seasons. Community diversity was characterized in terms of number of species accumulated, species richness, Shannon-Weiner indices of diversity, Pielou’s evenness, and Bray-Curtis similarity. A total of 134 families from 19 insect orders were recorded during the entire study period. Yenku Block A recorded the highest species richness (98) and the highest diversity index (14.97), corroborated by the highest Margalef index of 3.82 with a relatively even distribution of species (0.834) during the intermediate season, and recorded the lowest diversity (6.957) and species richness (41) during the dry season. On the whole, the Muni-Pomadzi Ramsar site showed a high diversity of insect species. The presence of species such as
Insects constitute a remarkably speciose group of organisms attributed mainly to their small size, which allows them to occupy niches not available to larger organisms. They are adapted to highly differing environments from the Arctic tundra to Alpine mountain summits as well as warmer tropical rainforest and coastal mangrove swamps and are able to tolerate extremes of temperature and other environmental conditions. Estimates of global species richness of insects vary from less than five million to as many as 80 million [
Insects are critical natural resources in ecosystems, particularly those of forests [
Insects are essential in the ecosystem by helping in nutrient recycling through leaf litter and wood degradation, carrion and dung disposal, and soil turnover. They play a major role in plant pollination and maintenance of plant community composition and structure via phytophagy [
The Muni-Pomadze Ramsar site was designated in 1992. A few years after its designation, an assessment of the insect diversity of the site and its surroundings in relation to habitat characteristics was carried out by the Coastal Wetlands Management Project (CWMP) funded by the Global Environment Facility (GEF) [
The Muni-Pomadze Ramsar site is situated to the west of the coastal town of Winneba in the Central Region of Ghana, approximately 55 km from Accra and encompasses approximately 90 km2 of the watershed surrounding the Muni Lagoon as well as two protected areas: Yenku Block A and Yenku Block B [
The field studies were carried out in July 2011, January, and June 2012, the wet, dry, and intermediate seasons, respectively. Eight main sampling methods were employed in the collection of insects. Butterfly nets were used for butterflies, dragonflies, and other high flying insects; visual observations and counts were done for those insects that were missed by the nets and also for insects species of which individuals had already been captured since it was not necessary to capture more insects than necessary. At each site, one Malaise trap for smaller, flying, mainly nocturnal insects, one flight interception trap (FIT) designed to intercept insects in flight and five Charaxes traps for alcohol-loving butterflies and other insects that are attracted to fermenting foods were set up. Rotten banana, mashed and mixed with alcohol (palm wine and or beer), was used as bait for the Charaxes traps. In addition, pitfall and yellow pan traps (five of each) were randomly set up at each site for crawling and ground dwelling insects and insects attracted by the yellow colour; sweeping was done for vegetation-dwelling insects and handpicking with forceps was done for insects within easy reach. Light trapping which lasted about two hours was done for the nocturnal insects along a small stream at Yenku Block B.
In addition to the various trapping methods, random walk sampling was undertaken by three persons for a minimum of three hours during each sampling period twice each day for seven days at each site. Visual observations and counts were done mainly for the dragonflies since they are very fast fliers and difficult to catch.
Insects collected were killed using a killing bottle containing ethyl acetate and kept either in alcohol or glassine envelops for later examination and identification. Identification of insects was done with reference to the collection in the Museum of the Department of Animal Biology and Conservation Science, University of Ghana, as well as with reference to Carter [
Cluster analysis was performed using Bray-Curtis similarity. Species contributing at least 20 individuals of the total abundance at each sampling site were included in the analysis. The original data was transformed (fourth root transformation) and standardized in order to minimize the weighting of numerically dominant species.
Five diversity indices were computed [
A total of 8634 individual insects belonging to 134 families and 19 orders were recorded in the survey. We present the butterflies and dragonflies data separately because of their numerical abundance, conservation interest, and role as indicators of ecosystem health but group all the other insects.
130 species of butterflies (Table
Butterfly species recorded over the entire survey period.
Species | Yenku Block A | Yenku Block B | ||||
---|---|---|---|---|---|---|
July | January | June | July | January | June | |
|
2 | 2 | 1 | 0 | 0 | 1 |
|
1 | 1 | 0 | 0 | 0 | 0 |
|
12 | 2 | 4 | 0 | 0 | 0 |
|
2 | 1 | 0 | 0 | 0 | 0 |
|
5 | 1 | 2 | 0 | 0 | 0 |
|
2 | 1 | 0 | 0 | 0 | 0 |
|
9 | 2 | 3 | 0 | 0 | 0 |
|
4 | 1 | 2 | 0 | 0 | 0 |
|
14 | 1 | 4 | 0 | 0 | 0 |
|
3 | 0 | 2 | 0 | 0 | 0 |
|
12 | 3 | 23 | 0 | 0 | 0 |
|
9 | 2 | 4 | 55 | 0 | 1 |
|
3 | 0 | 2 | 0 | 0 | 0 |
|
1 | 0 | 1 | 0 | 0 | 0 |
|
2 | 1 | 1 | 0 | 0 | 0 |
|
3 | 6 | 3 | 3 | 0 | 14 |
|
1 | 3 | 5 | 10 | 0 | 4 |
|
2 | 2 | 9 | 2 | 0 | 3 |
|
1 | 1 | 3 | 1 | 0 | 0 |
|
0 | 0 | 2 | 0 | 0 | 0 |
|
3 | 1 | 1 | 0 | 0 | 0 |
|
43 | 3 | 27 | 2 | 0 | 6 |
|
1 | 1 | 2 | 6 | 5 | 60 |
|
0 | 11 | 2 | 0 | 0 | 10 |
|
2 | 1 | 2 | 1 | 1 | 0 |
|
3 | 3 | 5 | 0 | 0 | 0 |
|
0 | 2 | 1 | 0 | 0 | 0 |
|
2 | 1 | 3 | 0 | 0 | 0 |
|
13 | 6 | 29 | 75 | 3 | 66 |
|
8 | 1 | 14 | 0 | 0 | 1 |
|
2 | 1 | 1 | 0 | 0 | 0 |
|
7 | 0 | 1 | 0 | 0 | 0 |
|
2 | 4 | 2 | 0 | 0 | 0 |
|
1 | 1 | 3 | 0 | 0 | 0 |
|
2 | 2 | 1 | 0 | 1 | 0 |
|
1 | 1 | 2 | 0 | 0 | 0 |
|
1 | 2 | 0 | 0 | 0 | 0 |
|
2 | 3 | 5 | 7 | 6 | 13 |
|
4 | 5 | 8 | 37 | 13 | 65 |
|
0 | 4 | 7 | 0 | 0 | 24 |
|
0 | 0 | 1 | 0 | 0 | 0 |
|
0 | 0 | 2 | 0 | 0 | 0 |
|
1 | 0 | 3 | 0 | 0 | 0 |
|
1 | 2 | 4 | 16 | 4 | 11 |
|
4 | 5 | 6 | 0 | 2 | 14 |
|
2 | 1 | 0 | 1 | 0 | 0 |
|
4 | 1 | 1 | 0 | 0 | 0 |
|
0 | 1 | 3 | 0 | 0 | 0 |
|
11 | 3 | 3 | 1 | 0 | 0 |
|
13 | 2 | 5 | 2 | 0 | 3 |
|
0 | 1 | 3 | 0 | 0 | 0 |
|
1 | 1 | 5 | 0 | 0 | 1 |
|
5 | 0 | 1 | 6 | 0 | 0 |
|
0 | 2 | 0 | 0 | 0 | 0 |
|
0 | 1 | 1 | 0 | 0 | 0 |
|
0 | 1 | 0 | 0 | 0 | 0 |
|
18 | 8 | 21 | 112 | 11 | 66 |
|
3 | 5 | 2 | 0 | 1 | 0 |
|
23 | 4 | 29 | 0 | 0 | 0 |
|
3 | 1 | 2 | 0 | 0 | 0 |
|
2 | 4 | 3 | 1 | 0 | 1 |
|
1 | 2 | 1 | 0 | 0 | 2 |
|
3 | 2 | 5 | 1 | 0 | 0 |
|
2 | 1 | 3 | 1 | 0 | 0 |
|
1 | 1 | 2 | 1 | 0 | 0 |
|
2 | 125 | 8 | 13 | 24 | 7 |
|
0 | 1 | 2 | 0 | 0 | 0 |
|
17 | 8 | 9 | 206 | 5 | 40 |
|
9 | 2 | 3 | 16 | 2 | 11 |
|
6 | 13 | 8 | 3 | 1 | 11 |
|
11 | 3 | 4 | 7 | 1 | 0 |
|
0 | 0 | 1 | 0 | 0 | 0 |
|
13 | 2 | 5 | 4 | 0 | 0 |
|
4 | 2 | 1 | 0 | 0 | 0 |
|
3 | 4 | 6 | 0 | 2 | 26 |
|
4 | 2 | 3 | 1 | 1 | 10 |
|
18 | 15 | 21 | 2 | 3 | 29 |
|
22 | 8 | 18 | 0 | 3 | 35 |
|
5 | 3 | 6 | 0 | 0 | 0 |
|
21 | 8 | 33 | 0 | 0 | 0 |
|
18 | 10 | 22 | 0 | 0 | 0 |
|
8 | 3 | 5 | 0 | 0 | 0 |
|
0 | 1 | 3 | 0 | 0 | 0 |
|
1 | 0 | 8 | 3 | 1 | 0 |
|
8 | 3 | 23 | 4 | 2 | 3 |
|
9 | 4 | 22 | 7 | 25 | 13 |
|
7 | 2 | 3 | 5 | 8 | 3 |
|
12 | 8 | 14 | 11 | 5 | 7 |
|
18 | 2 | 24 | 20 | 3 | 85 |
|
6 | 3 | 9 | 9 | 3 | 62 |
|
4 | 0 | 5 | 3 | 2 | 5 |
|
4 | 4 | 6 | 3 | 0 | 3 |
|
68 | 15 | 87 | 12 | 8 | 66 |
|
32 | 5 | 46 | 9 | 1 | 20 |
|
16 | 1 | 19 | 12 | 0 | 14 |
|
18 | 4 | 7 | 14 | 0 | 2 |
|
14 | 3 | 12 | 21 | 0 | 9 |
|
9 | 8 | 10 | 7 | 1 | 0 |
|
0 | 0 | 3 | 0 | 0 | 0 |
|
78 | 29 | 31 | 21 | 21 | 69 |
|
42 | 7 | 16 | 5 | 9 | 16 |
|
0 | 0 | 1 | 0 | 0 | 0 |
|
56 | 71 | 34 | 23 | 1 | 8 |
|
34 | 9 | 27 | 5 | 1 | 19 |
|
51 | 12 | 10 | 4 | 0 | 6 |
|
17 | 8 | 11 | 2 | 0 | 26 |
|
9 | 2 | 1 | 4 | 0 | 2 |
|
2 | 1 | 1 | 0 | 0 | 0 |
|
0 | 1 | 1 | 0 | 0 | 0 |
|
0 | 0 | 2 | 0 | 1 | 0 |
|
5 | 1 | 3 | 0 | 0 | 0 |
|
3 | 2 | 4 | 1 | 0 | 0 |
|
2 | 1 | 3 | 0 | 0 | 0 |
|
1 | 0 | 2 | 0 | 0 | 0 |
|
3 | 2 | 1 | 3 | 5 | 12 |
|
2 | 5 | 3 | 5 | 27 | 0 |
|
6 | 2 | 1 | 5 | 8 | 0 |
|
0 | 3 | 1 | 0 | 8 | 0 |
|
5 | 8 | 11 | 3 | 39 | 25 |
|
0 | 1 | 0 | 0 | 0 | 0 |
|
0 | 1 | 1 | 0 | 0 | 0 |
|
0 | 0 | 1 | 0 | 0 | 0 |
|
0 | 0 | 1 | 0 | 0 | 0 |
|
61 | 103 | 76 | 7 | 0 | 51 |
|
3 | 2 | 3 | 0 | 1 | 0 |
|
4 | 3 | 2 | 1 | 0 | 0 |
|
2 | 1 | 4 | 0 | 0 | 2 |
|
3 | 2 | 1 | 2 | 0 | 1 |
|
2 | 3 | 6 | 1 | 0 | 0 |
|
0 | 0 | 3 | 0 | 0 | 0 |
Table
Calculation of suite of diversity indices for butterfly species collected from the two sites at Muni-Pomadze, Yenku Block A and Yenku Block B.
Sample site |
|
|
|
|
|
---|---|---|---|---|---|
YBAJUL | 106 | 1061 | 15.07 | 0.8547 | 3.986 |
YBAJAN | 111 | 684 | 16.85 | 0.7554 | 3.558 |
YBAJUN | 122 | 1011 | 17.49 | 0.8513 | 4.09 |
YBBJUL | 60 | 825 | 8.786 | 0.7358 | 3.013 |
YBBJAN | 41 | 269 | 7.15 | 0.8354 | 3.102 |
YBBJUN | 53 | 1064 | 7.461 | 0.8602 | 3.415 |
YBA: Yenku Block A; YBB: Yenku Block B; JUL: July; JAN: January; JUN: June;
Yenku Block B (YBB) recorded a relatively lower evenness, (
From the cluster analysis (Figure
Dendrogram of butterfly species at the two sites in Winneba July (2011), January, and June, in 2012. The cluster analysis was performed using group-average linking on Bray-Curtis species similarity from fourth root transformed abundance data.
Figure
Dendrogram of butterfly species occurring at Muni-Pomadze using group-average linking on Bray-Curtis species similarity from fourth root transformed abundance data. The analysis was performed on species contributing abundance of 20 or more.
Yenku Block B recorded the highest species richness (
Diversity indices for Odonata collected from the two sites at Muni-Pomadze, Yenku Block A and Yenku Block B.
Sample |
|
|
|
|
|
---|---|---|---|---|---|
YBAJUL | 7 | 77 | 1.381 | 0.7476 | 1.455 |
YBBJUL | 10 | 68 | 2.133 | 0.8306 | 1.912 |
YBAJAN | 7 | 69 | 1.417 | 0.6608 | 1.286 |
YBBJAN | 5 | 26 | 1.228 | 0.8906 | 1.433 |
YBAJUN | 8 | 44 | 1.85 | 0.776 | 1.614 |
YBBJUN | 8 | 40 | 1.898 | 0.8874 | 1.845 |
YBA: Yenku Block A; YBB: Yenku Block B; JUL: July; JAN: January; JUN: June;
A total of 3720 insects belonging to 19 other insect orders were recorded from the traps. Diptera was the most abundant (1932) as well as the most diverse order with 36 families, followed by Coleoptera with 21 families and Hymenoptera with 13 families (Table
Insects families recorded over the entire survey period.
Yenku Block A | Yenku Block B | |||||
---|---|---|---|---|---|---|
Family | July | January | June | July | January | June |
Gryllidae | 8 | 7 | 15 | 6 | 13 | 11 |
Acrididae | 6 | 6 | 4 | 7 | 5 | 14 |
Tettigonidae | 3 | 0 | 4 | 12 | 3 | 3 |
Tridactylidae | 0 | 2 | 5 | 0 | 1 | 4 |
Tetrigidae | 2 | 1 | 1 | 6 | 2 | 1 |
Formicidae | 81 | 96 | 31 | 75 | 39 | 29 |
Apidae | 6 | 0 | 8 | 4 | 1 | 5 |
Evaniidae | 1 | 3 | 1 | 3 | 1 | 1 |
Sphecidae | 2 | 2 | 5 | 0 | 1 | 8 |
Vespidae | 0 | 3 | 11 | 0 | 1 | 6 |
Braconidae | 3 | 7 | 13 | 8 | 6 | 15 |
Ichneumonidae | 2 | 2 | 4 | 4 | 1 | 3 |
Scelionidae | 0 | 3 | 2 | 1 | 2 | 1 |
Halictidae | 0 | 1 | 2 | 2 | 1 | 1 |
Pompylidae | 1 | 0 | 4 | 0 | 0 | 3 |
Chalcididae | 0 | 2 | 2 | 0 | 1 | 4 |
Eulophidae | 1 | 0 | 3 | 0 | 2 | 4 |
Tiphiidae | 2 | 0 | 1 | 0 | 0 | 0 |
Blattidae | 6 | 5 | 9 | 1 | 4 | 1 |
Mantidae | 2 | 0 | 1 | 0 | 0 | 1 |
Noctuidae | 3 | 4 | 2 | 0 | 0 | 4 |
Arctidae | 0 | 1 | 0 | 1 | 0 | 2 |
Satyridae | 2 | 0 | 2 | 0 | 0 | 3 |
Pieridae | 0 | 0 | 3 | 1 | 1 | 2 |
Acraeidae | 0 | 0 | 1 | 1 | 0 | 0 |
Nymphalidae | 0 | 1 | 2 | 2 | 0 | 0 |
Termitidae | 1 | 1 | 2 | 0 | 2 | 5 |
Rhinotermitidae | 0 | 0 | 1 | 0 | 0 | 2 |
Kalotermitidae | 2 | 0 | 0 | 0 | 0 | 1 |
Cercopidae | 5 | 11 | 6 | 10 | 26 | 8 |
Aleyrodidae | 0 | 2 | 4 | 0 | 0 | 0 |
Aphididae | 0 | 0 | 3 | 0 | 0 | 0 |
Fulgoridae | 0 | 0 | 1 | 0 | 0 | 0 |
Cicadellidae | 2 | 3 | 13 | 17 | 9 | 13 |
Delphacidae | 0 | 0 | 2 | 3 | 2 | 2 |
Membracidae | 0 | 1 | 0 | 0 | 0 | 1 |
Pseudococcidae | 0 | 0 | 1 | 0 | 0 | 1 |
Dictyopharidae | 1 | 0 | 0 | 2 | 0 | 1 |
Psyllidae | 0 | 0 | 3 | 0 | 3 | 4 |
Acanalonidae | 1 | 0 | 0 | 0 | 0 | 1 |
Flatidae | 0 | 0 | 1 | 0 | 0 | 0 |
Isotomidae | 3 | 33 | 22 | 1 | 32 | 27 |
Calliphoridae | 2 | 2 | 5 | 31 | 2 | 3 |
Sepsidae | 0 | 0 | 3 | 5 | 0 | 0 |
Tachinidae | 4 | 5 | 13 | 0 | 12 | 19 |
Sarcophagidae | 3 | 1 | 15 | 1 | 3 | 6 |
Culicidae | 1 | 5 | 8 | 34 | 6 | 17 |
Muscidae | 2 | 1 | 9 | 3 | 1 | 7 |
Tephritidae | 69 | 24 | 29 | 4 | 5 | 22 |
Drossophilidae | 1 | 53 | 24 | 3 | 5 | 993 |
Phoridae | 11 | 14 | 24 | 7 | 15 | 28 |
Tipulidae | 4 | 0 | 2 | 0 | 0 | 3 |
Asilidae | 0 | 0 | 2 | 7 | 0 | 4 |
Diopsidae | 0 | 0 | 0 | 0 | 0 | 1 |
Dolichopodidae | 1 | 1 | 2 | 9 | 0 | 4 |
Syrrphidae | 2 | 1 | 7 | 5 | 2 | 10 |
Rhagionidae | 0 | 0 | 1 | 0 | 0 | 3 |
Stratiomyiidae | 0 | 0 | 2 | 0 | 0 | 1 |
Bombylidae | 2 | 0 | 2 | 1 | 0 | 1 |
Tabanidae | 19 | 0 | 28 | 1 | 0 | 3 |
Glossinidae | 1 | 0 | 92 | 0 | 0 | 8 |
Simulidae | 2 | 0 | 0 | 3 | 0 | 1 |
Mycetophilidae | 0 | 0 | 4 | 0 | 0 | 9 |
Sciaridae | 0 | 0 | 2 | 0 | 0 | 6 |
Chironomidae | 0 | 0 | 0 | 3 | 0 | 1 |
Ceratopogonidae | 0 | 0 | 3 | 0 | 0 | 2 |
Conopidae | 0 | 0 | 2 | 3 | 0 | 0 |
Lauxanidae | 0 | 0 | 0 | 0 | 0 | 2 |
Psychodidae | 0 | 0 | 1 | 0 | 0 | 0 |
Cecidomyiidae | 1 | 0 | 2 | 0 | 0 | 0 |
Platypezidae | 0 | 0 | 1 | 0 | 0 | 0 |
Trichoceridae | 0 | 0 | 1 | 0 | 0 | 4 |
Acroceridae | 0 | 0 | 0 | 0 | 0 | 2 |
Empididae | 0 | 0 | 2 | 13 | 0 | 18 |
Therevidae | 1 | 0 | 3 | 0 | 3 | 1 |
Otitidae | 0 | 0 | 12 | 0 | 0 | 3 |
Anthomyiidae | 0 | 0 | 0 | 8 | 0 | 11 |
Bibionidae | 0 | 0 | 0 | 7 | 0 | 3 |
Chrysomelidae | 11 | 3 | 12 | 19 | 2 | 8 |
Carabidae | 23 | 0 | 14 | 8 | 4 | 2 |
Tenebrionidae | 3 | 1 | 6 | 1 | 0 | 0 |
Scarabaeidae | 167 | 0 | 44 | 2 | 0 | 2 |
Mordellidae | 5 | 0 | 1 | 8 | 1 | 1 |
Phalacridae | 0 | 0 | 2 | 0 | 0 | 1 |
Coccinellidae | 2 | 0 | 0 | 0 | 3 | 0 |
Dermestidae | 0 | 0 | 0 | 4 | 0 | 0 |
Meloidae | 0 | 0 | 0 | 3 | 0 | 0 |
Curcujidae | 0 | 1 | 6 | 0 | 0 | 14 |
Scolytidae | 0 | 0 | 1 | 1 | 0 | 0 |
Lampyridae | 0 | 0 | 5 | 13 | 0 | 2 |
Staphylinidae | 5 | 0 | 15 | 52 | 0 | 51 |
Ptinidae | 0 | 0 | 1 | 0 | 0 | 1 |
Lucanidae | 0 | 0 | 2 | 0 | 0 | 1 |
Hesteridae | 0 | 0 | 2 | 0 | 0 | 0 |
Anthicidae | 0 | 0 | 0 | 0 | 0 | 1 |
Cleridae | 0 | 0 | 0 | 0 | 0 | 1 |
Scaphididae | 0 | 0 | 2 | 0 | 0 | 0 |
Curculionidae | 5 | 0 | 6 | 1 | 0 | 6 |
Cerambycidae | 1 | 0 | 1 | 0 | 0 | 2 |
Hydropsychidae | 5 | 0 | 3 | 14 | 0 | 4 |
Polycentropodidae | 3 | 0 | 0 | 0 | 0 | 5 |
Philopotamidae | 0 | 0 | 1 | 4 | 0 | 0 |
Leptoceridae | 2 | 0 | 1 | 10 | 0 | 2 |
Psychomyiidae | 0 | 0 | 0 | 2 | 0 | 0 |
Thripidae | 2 | 0 | 7 | 7 | 1 | 13 |
Forfinculidae | 1 | 0 | 2 | 0 | 0 | 1 |
Labiidae | 0 | 0 | 2 | 0 | 1 | 0 |
Carcinophoridae | 0 | 1 | 1 | 0 | 0 | 2 |
Libellulidae | 1 | 0 | 2 | 0 | 0 | 1 |
Coenagrionidae | 0 | 0 | 0 | 0 | 0 | 1 |
Pyrrhocoridae | 1 | 1 | 3 | 2 | 0 | 3 |
Coreidae | 1 | 0 | 1 | 2 | 0 | 0 |
Pentatomidae | 3 | 1 | 3 | 1 | 0 | 2 |
Reduvidae | 0 | 1 | 3 | 1 | 2 | 1 |
Lygaeidae | 0 | 0 | 2 | 1 | 1 | 2 |
Berytidae | 0 | 1 | 1 | 0 | 0 | 0 |
Largidae | 2 | 0 | 0 | 0 | 1 | 1 |
Nepidae | 0 | 0 | 0 | 1 | 0 | 0 |
Alydidae | 0 | 0 | 1 | 1 | 0 | 0 |
Cydnidae | 1 | 0 | 2 | 0 | 0 | 1 |
Thyreocoridae | 1 | 0 | 1 | 0 | 0 | 2 |
Ascalaphidae | 0 | 0 | 1 | 0 | 0 | 0 |
Sialidae | 0 | 0 | 0 | 1 | 0 | 0 |
Phasmatidae | 1 | 0 | 3 | 0 | 0 | 1 |
Oligotomidae | 0 | 0 | 1 | 0 | 0 | 0 |
Machilidae | 0 | 0 | 0 | 0 | 0 | 1 |
Panorpidae | 0 | 0 | 0 | 0 | 0 | 1 |
The diversity indices for the total of 127 insect families caught in the traps are presented in (Table
Diversity indices for insect families collected from the two sites at Muni-Pomadze, Yenku Block A and Yenku Block B.
Sample |
|
|
|
|
|
---|---|---|---|---|---|
YBAJUL | 59 | 513 | 9.294 | 0.6544 | 2.668 |
YBAJAN | 41 | 314 | 6.957 | 0.694 | 2.577 |
YBAJUN | 98 | 651 | 14.97 | 0.8347 | 3.827 |
YBBJUL | 63 | 472 | 10.07 | 0.8245 | 3.416 |
YBBJAN | 42 | 227 | 7.558 | 0.8075 | 3.018 |
YBBJUN | 91 | 1515 | 12.29 | 0.4405 | 1.987 |
YBA: Yenku Block A; YBB: Yenku Block B; JUL: July; JAN: January; JUN: June;
A cluster analysis using Bray-Curtis similarity was performed for all the insects collected from the traps at both sites for the three sampling seasons (Figure
Dendrogram of all other insects collected from traps at the two sites in Winneba (YBA and YBB) in July (2011), January, and June, in 2012. The cluster analysis was performed using group-average linking on Bray-Curtis similarity from fourth root transformed abundance data.
The insects were averaged over the orders and similarity analyses were performed on all 3720 insects from the 19 orders collected from the traps over the entire sampling period. The cluster analysis revealed three distinct clusters/groupings above a Bray-Curtis similarity 25% (Figure
Dendrogram of all insect orders collected from traps at the two sites (YBA and YBB) in July (2011), January, and June, in 2012. The cluster analysis was performed using group-average linking on Bray-Curtis similarity from fourth root transformed abundance data.
130 species of butterflies belonging to nine families were recorded during the survey. From the diversity indices for the butterfly species calculated for the three sampling seasons, the lowest abundance of butterflies at YBB in January (
The low evenness (
Factors such as resource availability for adults and larval host plants, behavioural traits, and interaction with other species [
Although Yenku Block A (YBA) recorded a high diversity (Margalef index
The species population structure could be considered homogenous, below a Bray-Curtis similarity of about 53%, however, homogeneity begins to break down leading to the formation of two clusters of species communities around 58%: YBBJUL, YBAJUL, YBAJUN, and YBBJUN forming one cluster and YBAJAN and YBBJAN forming the other (Figure
Species of butterflies such as
Species common to both sites were
Satyrids are generally dusty to dark brown and blend well with the dark vegetation of forested areas and forest undergrowths and are associated with grasses. Species such as
Most of the eight species of
The Lycaenids such as
Dragonflies are relatively ever-present in freshwater wetlands, and occupy a critical trophic niche in these systems. The adults are easily sampled; they are insects that are susceptible to human disturbance and constitute good candidates for wetlands assessment [
All the dragonfly species recorded in Yenku Blocks A and B are widespread species and therefore classified as of least concern [
A total of 3720 insects belonging to 19 orders were recorded from the traps. Diptera was the most abundant (1932) as well as the most diverse order with 36 families, followed by Coleoptera with 21 families and Hymenoptera with 13 families. The high numbers of Dipterans may have resulted from the use of the Malaise traps and the flight interception traps employed in this study which are basically designed to trap small flying insects, mainly Diptera and Hymenoptera. They were set up close to streams and many of the insects recorded were aquatic species that may have been trapped on emergence or as they came to lay eggs in or close to the water. Flight interception traps are also designed to intercept the flight of small to medium-sized flying insects. In a baseline survey conducted in 1997 [
Insect diversity was the highest at both sites in June (intermediate season) most probably because, during this time of the year, there are ample food resources for the insects and rainfall is not too heavy since heavy rainfall sweeps most insects away and destroys many of their food resources. The high numbers of Dipterans accounted for the highest abundance (
From the cluster analysis the insect species composition at Yenku Blocks A and B had a fairly similar species distribution for June and July (Figure
The cluster analysis performed on the insect orders revealed three distinct clusters/groupings above a Bray-Curtis similarity 25% with homogeneity below a Bray-Curtis of 20%, indicating a high level of dissimilarity in distribution (Figure
It is interesting to note that Diptera, Hymenoptera, and Coleoptera cluster together around 95% indicating a high level of similarity in distribution. These three orders contributed to 81% of the entire insect collection from the traps at both sites.
The presence of dung beetles, Scarabaeidae, in large numbers at Yenku Block A during the wet season sampling is an indication of the presence of large mammals at this site which is typical for the kind of vegetation found at the site.
The total number of species recorded in the current study and composition of the various taxonomic groups suggest an increase in insect abundance when compared with the findings in the 1997 survey. However, with the exception of butterflies, a direct comparison of overall insect abundance recorded in the two studies would not be appropriate because of the limited range of techniques and different sampling methods used in the 1997 study. The sampling methods used for butterflies in the two studies were similar and therefore the results are comparable. 74 (57% of the total) butterfly species were common to both Yenku Blocks A and B in this survey as compared to 22 species (29.3% of the total) that were common to both sites in 1997 [
No butterfly species were recorded only in Yenku Block B in the current survey; however Gordon and Cobblah [
Many habitat changes had occurred at the Ramsar site since its designation in 1992. The presence of pockets of farmlands created from portions of the Eucalytus plantation within Yenku Block A that had been cut down and converted to maize and cassava farmlands, for example, had created a wider range of habitat types and adequate food resources as well as pockets of open areas for easy flight allowing for the colonization of more butterfly species. At the initial stages of habitat loss, new habitats occur as gaps within the original habitat; however, as the proportion of new habitats increases in the landscape, the remaining areas of original habitat will be smaller and more isolated from one another [
The survey revealed high levels of insect diversity at the Muni-Pomadze Ramsar site with 134 insect families belonging to 19 orders recorded, including 130 species of butterflies. Butterfly species richness was greater at Yenku Block A (130) than at Yenku Block B (74). As was the case in a survey conducted in 1997 [
Species such as
The presence of deep forest species such as
The Muni-Pomadzi Ramsar site is still in a relatively good condition although more efforts should be put in place by the Forestry Commission of Ghana to maintain it and prevent encroachment by farmers and loggers since it is a site for conservation not only in Ghana but also in West Africa.
All authors agree to the publication of this paper and they do not have any conflict of interests with any party or commercial identity. They have no involvement that might raise questions of bias in this reported work or in its conclusions, implications, or opinions.
This study was undertaken under the building capacity to meet the climate change challenge (B4C) - Ghana project, which is implemented by a consortium of three institutions, the University of Ghana (lead), the Centre for African Wetlands, and the Ghana Wildlife Society, with funding from the Open Society Foundations. The authors are grateful to the Open Society Foundations for the funds that made the study possible.