Effect of anthropogenic pressure on grasshopper (Orthoptera: Acridomorpha) species diversity in three forests in southern Cameroon.
Tropical rainforests shelter an important part of the world's biodiversity and represent an important stake for all countries, in particular with regard to the effects of anthropogenic disturbances and climate change. Forest biodiversity remains poorly studied throughout the African continent (Basset et al. 2001), where these ecosystems are heavily deforested, particularly in the Congo Basin. The rate of deforestation doubled in the Congo Basin between 1990 and 2005 (Tchatchou et al. 2015). These forests are subject to growing anthropogenic pressures leading to their fragmentation and progressive destruction (de Wasseige et al. 2012). The direct causes of deforestation include intensification of mining, population expansion, intensive agricultural practices, and construction of dams that severely alter the structure of the forest and its dependent biodiversity. As the primary means of livelihood for semi-subsistence farmers in the Congo Basin, shifting cultivation uses forest resources for agricultural production and as a source of non-wood products (Brown 2006). Cameroon loses about 140,000 hectares of forest per year (Ndoye and Kaimowitz 2000). In its southern part, industrial wood production has increased from 2.3 million m[sup.3] in 1991 to more than 3 million m[sup.3] in 2000 (de Wasseige et al. 2012). The destruction of these forests has altered the biophysical structure of the natural environment and leads to the breakdown of ecosystem equilibrium and the extinction of species as well as the modification of the structure of floral and faunal communities. The faunal composition is known to be negatively affected by this clearing, with reduction of canopy cover being the major factor of these losses (Scott et al. 2006, Steer et al. 2009). The habitat loss is predicted to greatly impact invertebrates' species diversity (Chinery 1993); these organisms are less mobile than vertebrates, have short life cycles, and are more specialized in micro-habitats due to their specificity to host plants.
Grasshoppers are a common and diverse invertebrate group worldwide (Gangwere et al. 1997, Song 2010, Zhang 2011). They are a dominant group of herbivorous insects with up to 20-30% of all arthropod biomass (Soliman et al. 2017) and occasionally constituting as much as half of the biomass in an environment (Gillon 1983). This group plays an important role in terrestrial food webs and is known to be a good source of protein for other animals such as amphibians, small reptiles, birds, and small mammals; therefore, their scarcity may disturb the trophic structure in an ecosystem (Schmidt et al. 1991, Soliman et al. 2017). Grasshoppers are important bioindicators of threatened environments because of their specific microhabitat preferences, functional importance in ecosystems, sensitivity to the modification of biotic and abiotic factors of their habitats, and the ease with which they can be sampled (Armstrong and van Hensbergen 1997, Samways 1997, Andersen et al. 2001, Guido and Gianelle 2001, Soliman et al. 2017). Diversity and community structure of grasshoppers as they relate to anthropogenic activities, types of vegetation, and climate change have been studied in many regions of the world (Otte 1976, Kemp et al. 1990, Clayton 2002, Torrusio et al. 2002, Gebeyehu and Samways 2003, Steck et al. 2007, Saha and Haldar 2009, Sirin et al. 2010, Branson 2011, Chen et al. 2011, Kekeunou et al. 2017). However, despite the high rate of deforestation observed, the bioindicator potential of grasshoppers in the Congo Basin area, and particularly in Cameroon, has been largely neglected. Apart from the recent works of Seino et al. (2013) and Kekeunou et al. (2017) on the diversity of acridoids in higher mountains in West Cameroon, abundance and grasshopper diversity have been poorly studied. The present article is a contribution to the understanding of the effect of anthropogenic pressure and forest degradation on the abundance and diversity of grasshopper species in southern Cameroon.
Materials and methods
Study sites. -Grasshoppers were collected over a year in three localities (Ongot, Zamakoe, and Ngutadjap; Fig. 1) in the forest area located on the margins of southern Cameroon plateau (3[degrees]27'N, 11[degrees]32'E and 4[degrees]10'N, 11[degrees]49'E). This area, about 650-700 m in elevation, is a part of the plateau that forms the northern and western edges of the Congo Basin (Westphal et al. 1981). The climate is typical of the Guinean zone with four seasons comprised of a long dry season (mid-November to mid-March), a short rainy season (mid-March to June), a short dry season (July to mid-September), and a long rainy season (mid-September to mid-November). Precipitation ranges from 1500-2000mm per year (Amou'ou et al. 1985, Santoir and Bopda 1995). The southern Cameroonian forest is dominated by Sterculiaceae and Ulmacae, and its undergrowth is made up of herbaceous plants such as Maranthaceae and Acanthaceae (Westphal et al. 1981). In this ecosystem, the natural vegetation is regularly degraded by the economic exploitation of wood and the practice of slash-and-burn agriculture (Santoir and Bopda 1995). The resulting bushy vegetation after degradation is less diversified and dominated by Chromolaena odorata , Ageratum conizoides , Synedrella nodiflora , and Imperata cylindrica . Plantain, cassava, yam, maize, and groundnut are the main food crops, while industrial crops include cocoa, coffee, sweet banana, and palm oil.
Fig. 1: Study sites in relation to vegetation types in Cameroon (see Mertens et al. 2012). [see PDF for image]
Grasshoppers were sampled in three forest ecosystems, each with different levels of anthropogenic pressure and degradation: Ongot forest, 14 to 88 inhabitants/km[sup.2] located in the division of Mefou and Akono, near Yaounde; Zamakoe forest, 10 to 41 inhabitants/km[sup.2] in the division of Nyong and So'o, near Mbalmayo; and Ngutadjap forest, 2 to 15 inhabitants/km[sup.2] in the division of Ntem Valley, near Ebolowa (Gockowski 1996). Plant species richness is higher in the less degraded Ngutadjap forest, lower in the Zamakoe forest, and lowest in the Ongot forest (Suppl. material 1). Gockowski (1996) showed that the residents of Ongot draw more income from paid work and extensive agriculture. In Ngutadjap, people depend more on hunting and fishing activities, while Zamakoe is a transition zone between the conditions of Ongot and Ngutadjap forests.
Grasshopper sampling. -The grasshopper species were sampled every month from the forests of Ongot, Zamakoe, and Ngutadjap using sweep nets, quadrats, and pitfall traps. Samples by net were made randomly for 30 min; grasshoppers were also captured by hand on the litter in 22 movable iron quadrats of 1 m[sup.2] each. These quadrats were placed every 10m, on two parallel transects of 110m, separated from each other by 10m. Other specimens were collected in 10 pitfall traps (of 8cm diameter each), 1/3 filled with 5% formalin as a preservative; each trap was laid every 20m in the same transects after quadrat exploration.
Grasshopper identification. -The collected specimens were identified using keys from Dirsh (1956, 1961, 1965, 1966, 1970), Jago (1967), Kevan (1975), Hollis (1975), and Lecoq (1980).
Species richness, sampling efforts and species accumulation curves. -Species richness (S) is the number of species reported from each sampling site. We have estimated these theoretical values by the non-parametric estimators viz. , Chao1 and Abundance-based Coverage Estimator (ACE) (Marcon 2015) using the software EstimateS (Colwell 2013). The plots of cumulative species number per sample were generated using the same software with data randomized 100 times. We estimated the sampling effort as the ratio of observed species richness to theoretical species richness. Average efforts were compared using a Kruskal-Wallis H-test in the software PAST (Hammer et al. 2001).
Relative abundances. -The average relative abundances (Marcon 2015) were calculated using the following formula:
f x = a n x 1 + n x 2 + a[macron] + n x 17 N x 100
I[pounds sterling]nx 1+nx 2+...+nx 17 is the sum of abundances of species x from the first to the seventeenth month in a given site; N is the sum of abundances of all the species in the three sites. Mean abundance between the different sites and between species were compared by the Kruskal-Wallis H-test while comparisons of mean abundances for two samples were made by the Wilcoxon W-test using PAST.
Abundance distribution models. -The abundance distributions of the reported species were compared to the geometric distribution model of Motomura, the broken stick model of Mac-Arthur, and the log series model of Fisher (Carlo et al. 1998, Cielo Filho et al. 2012, Havyarimana et al. 2013, Marcon 2015) to find the one that fits most to our dataset. These models provide information on how species are distributed and on how they share the available resources in the ecosystem (Havyarimana et al. 2013). PAST software automatically generates the results from the row data. The [CHI][sup.2] test was used in PAST to compare the observed abundance distribution to the expected for the three types of theoretical distributions tested.
Diversity. -Species diversity of grasshoppers was calculated in PAST and expressed as dominance (D), Shannon diversity (H), and evenness (H/Hmax) indexes (Carlo et al. 1998, Tadu et al. 2013, Marcon 2015, Kekeunou et al. 2017, Mbenoun Masse et al. 2017, Raghavender and Vastrad 2017). The Shannon index for two samples were compared using the Student t-test (Hutcheson 1970).
Similarity. -Similarities between the grasshopper communities were assessed by the Bray Curtis index (C[sub.n] ) (Bray and Curtis 1957, Tadu et al. 2013, Tadu and Djieto-Lordon 2014, Raghavender and Vastrad 2017) and the correspondence analysis of the species to the different communities (Yelland 2010). Cluster analysis was performed using the Paired Group Method (UPGMA) in PAST. PAST graphically generates the Euclidean distances between rows (species) and columns (sites/forests) for the correspondence analysis.
Species richness. -A total of 12 grasshopper species were identified belonging to two families: Pyrgomorphidae (two species) and Acrididae (10 species) (Fig. 2A). The subfamily Catantopinae was the most diverse with six species following by the Oxyinae and Pyrgomorphinae (two species each), and Acridinae and Coptacrinae with only one species each (Fig. 2B).
Fig. 2: Species richness from each study site. A. Families; B. Subfamilies. [see PDF for image]
Ten of the 12 identified species were collected by net, six species were collected in quadrats, and only two species in pitfalls (Table 1). Two species were collected only from the least disturbed forest of Ngutadjap (Gemeneta opilionoides and Parapetasia femorata ). Gemeneta terrea was collected from the two more disturbed forests of Ongot and Zamakoe, while Apoboleus degener was collected only from the most disturbed forest of Ongot. Pteropera carnapi , Cyphocerastis hopei , and Taphronota ferruginea were collected only from the moderately anthropized forest of Zamakoe (Table 1). The remaining five species were common to all three localities.
Table 1: Species richness according to the different sampling methods in the forests. [see PDF for image]
Sampling effort and species accumulation curves. -Sampling captured almost the entire estimated species assemblage (95.3 [+ or -] 1.42%). No significant difference (H = 2, P = 0.36) was observed between the localities: Ngutadjap (97.0 [+ or -] 3%), Ongot (96.5 [+ or -] 3.5%), and Zamakoe (92.5 [+ or -] 2.5%) (Table 2). The species accumulation curve of each forest started to i[logical not]atten out towards the end of the sampling period (Fig. 3).
Fig. 3: Species accumulation curves of the study sites. [see PDF for image]
Table 2: Sampling effort and diversity of grasshopper species from the study sites. The values in brackets represent the theoretical species richness; a and b: the results of Shannon diversity index test for two samples. [see PDF for image]
Relative abundance. -A total of 465 individuals were collected from the target localities (Appendix 1). We did not observe great differences in abundance between seasons (Appendix 1). Among these 465 individuals, 72 (16.8 [+ or -] 2.3%) were collected from the low anthropized forest of Ngutadjap, 167 (35.5 [+ or -] 2.8%) from the more anthropized forest of Ongot, and 226 (47.7 [+ or -] 3.0%) from the moderately anthropized forest of Zamakoe (Table 3). The mean abundances were significantly higher (H = 23.49, P < 0.0001) in the grasshopper community from Zamakoe, and significantly lower in that of Ngutadjap. Mazea granulosa reported from all localities was the most abundant species (79.2%) (Table 3). The abundance of this species significantly differed among the three sites (H = 22.02, P < 0.0001): 11.7% in Ngutadjap, 26.4% in Ongot, and 41.1% in Zamakoe (Table 3). The common species Holopercna gerstaeckeri and Serpusia opacula were less abundant than M. granulosa . All other species were present with very low abundances in the different sites studied (Table 3).
Table 3: The mean relative abundance (%) of species between the different study sites. Each value is: mean [+ or -] standard error; H-value: Kruskal Wallis test; P-value: probability; a, b and c: the results of the comparisons, with the Wilcoxon test, for two samples. [see PDF for image]
Abundance distribution models. -The grasshopper species collected during this study were distributed into seven abundance ranks in the Ongot and Ngutadjap forests and in nine abundance ranks in Zamakoe forest. The distribution models of species abundance from the target localities were very different from the geometric model of Motomora: Ongot ([CHI][sup.2] = 53.3; P < 0.001; Fig. 4A), Zamakoe ([CHI][sup.2] = 562.2; P < 0.001; Fig. 4B), and Ngutadjap ([CHI][sup.2] = 30.6; P < 0.001; Fig. 4C); the broken stick of MacArthur model: Ongot ([CHI][sup.2] = 88.6; P < 0.001; Fig. 4A), Zamakoe ([CHI][sup.2] = 290.8; P < 0.001; Fig. 4B), and Ngutadjap ([CHI][sup.2] = 27.4; P < 0.001; Fig. 4C). All the observed abundance distribution models were closer to, though slightly different from, Fisher' log-series distribution model: Ongot ([CHI][sup.2] = 17.1; P = 0.002; Fig. 4A), Zamakoe ([CHI][sup.2] = 110.5; P < 0.001; Fig. 4B), and Ngutadjap ([CHI][sup.2] = 11.1; P = 0.011; Fig. 4C). The rare species (average relative abundance <1%) accounted for 58% of the species collected in all three of the studied forests.
Fig. 4: Abundance distribution model of species in the different forests. A. Ongot; B. Zamakoe; C. Ngutadjap. [see PDF for image]
Diversity. -The dominance index showed that there are fewer dominant species in Zamakoe (0.71) than in Ongot (0.54) and Ngutadjap (0.47) (Table 2). The Shannon diversity index (H) was higher at Zamakoe (H = 1.18, H/Hmax = 0.23) followed by Ongot (H = 0.97, H/Hmax = 0.38) and lower at Ngutadjap (H = 0.73, H/Hmax = 0.46) (Table 2). The Shannon diversity index of grasshopper communities of Zamakoe and Ngutadjap forests were significantly different (t = 14.3, P = 0.005) (Table 2). All the above shows that the species diversity has increased with the level of forest degradation in the study site.
Similarity. -The cluster analysis based on species composition performed on the basis of Bray-Curtis index revealed that the grasshopper communities of Zamakoe and Ongot forests are more similar to each other (Fig. 5). The disposition of species by correspondence analysis shows that most of the species studied were closer to these two most degraded forests of Ongot and Zamakoe (Fig. 6). A. degener was specific to Ongot; P. carnapi , C. hopei , and T. ferruginea were specific to Zamakoe; and G. opilionoides and P. femorata were specific to Ngutadjap (Fig. 6).
Fig. 5: Similarity between the different forest grasshopper communities using the Bray-Curtis index. [see PDF for image]
https://binary.pensoft.net/fig/377310 10.3897/jor.29.33373.fig6 D36C881C-0DF0-51BC-9FF1-CFED63B65D2C
Fig. 6: Disposition of species between the different study sites using correspondence analysis. [see PDF for image]
Species richness and sampling effort. -The sampling efforts were high, varying between 87% and 93% in the forests studied, with no significant difference, which is consistent with the statement of Branson (2011) that evaluation and comparison of grasshopper diversities requires that all regions and ecosystems be studied in the same way. The species accumulation curve of each forest started to i[logical not]atten out towards the end of the sampling period; this shows that almost all the species had been collected: all the common species were sampled. The missing species are likely to be all rare taxa corresponding to the expected low abundance nature of tropical forest faunas.
Overall, 12 species were identified: seven in Ngutadjap and Ongot and nine in Zamakoe. Seino et al. (2013) and Kekeunou et al. (2017) have identified, respectively, 28 and 27 species in the mountainous area of West Cameroon. This considerable difference in species richness can be explained by the fact that (1) previous studies collected grasshoppers in both fallows and forests and (2) the works cited were conducted in the upland area of western Cameroon with two climatic seasons, while we carried out the present work in the southern Cameroon plateau with four climatic seasons. The structure, biology, and ecology of the grasshopper communities are logically expected to be different in the two different habitats.
Grasshoppers are indeed recognized as abundant insects in open environments, which may explain the low species richness observed in our work. Joubert et al. (2016) recently reported that grasshoppers constitute a signii[logical not]cant proportion of invertebrate diversity in grasslands; their abundance increases with burning, cattle grazing, and short vegetation. Spungis (2007) and Arya et al. (2015) also carried out studies in forests and found 14 and 12 species of grasshoppers identified, respectively, in the Western Himalaya in India and in the Ziemupe Nature Reserve forest in Latvia; the number of species of grasshoppers collected in these studies are similar to ours. Nevertheless, Raghavender and Vastrad (2017) report a high species richness, 30 species, in the forest of Dharwad in India. This difference may be explained by differences in the climate, types of vegetation, and grasshopper communities between southern Cameroon and the Dharwad region in India. In our study, the families were Acrididae (10 species) and Pyrgomorphidae (two species). Dirsh (1965, 1966, 1970) and Mestre and Chiffaud (2009) showed that these two taxa are the main acridid families in the fauna of both Cameroon and Congo Basin.
In the same way, Seino et al. (2013) and Kekeunou et al. (2017) found that Acrididae (18 and 22 species, respectively) and Pyrgomorphidae (four and six species, respectively) are the more speciose families in West Cameroon. The same results were given by Almeida and Camara (2008) in Brazil, and by Arya et al. (2015), More and Nikam (2016), and Raghavender and Vastrad (2017) in India. The Catantopinae was the richest subfamily in the study areas with three species in Ngutadjap and four species in Zamakoe and Ongot. Seino et al. (2013) reported this subfamily as most speciose in West Cameroon. After the Oedipodinae, the Catantopinae was also the richest subfamily in both agriculture and forest ecosystems of Dharwad, India (Raghavender and Vastrad 2017). The above results are consistent with the findings by Dirsh (1965) more than fifty years ago in Cameroon and in Africa.
Relative abundance and abundance distributions. -The abundance of grasshoppers in the three study sites increased with human pressure. In fact, it is already known that grasshopper abundance increases in dry grassland habitats and forests used by humans (Latchininsky and Gapparov 1996, 2011, Spungis 2007, Latchininsky 2008). These results contrast with those of Soliman et al. (2017) who reported higher species richness, abundance, and diversity in the less disturbed sites in South Cairo, Egypt. We can therefore assume that the behavior of grasshoppers in response to the environmental disturbances is influenced by the eco-climatic zone and the structure of plant and even animal communities.
In fact, ecosystem changes strongly affect behavior, especially of poikilotherms such as grasshoppers that feed on plant materials (Bronwyn 2013). The increase in abundance as the forest is opened up by human agency that was observed in our work is not due to an invasion by grassland or forest edge species, but of forest forms due to increased light penetration and, thus, a change in understory vegetation. The positive correlations that exist between the population density of grasshoppers and plant species diversity can be explained by both feeding and sheltering requirements of grasshoppers (Spungis 2007).
Disturbed and new habitats can be important for the spreading of some grasshopper forms (Samways et al. 1997, Sergeev 1998, Latchininsky et al. 2011). At the same time, some grasshopper species are threatened by anthropogenic pressures, such as overgrazing and ploughing (Latchininsky and Gapparov 1996, 2011, Sergeev 1998). The abundance distribution of the species observed in this work were most similar to, though slightly different from, Fisher' log-series distribution model. Therefore, species with low abundance were the most numerous in the forests studied compared to the most abundant ones or those with intermediate abundance (Havyarimana et al. 2013). This distribution model shows that although they had different levels of utilization and degradation, these three forest ecosystems are disturbed by human activities (Hughes 1986). Under these conditions, the available resources may be immobilized by a small number of species that develop strategies of resistance to human disturbances (Ramade 2009, Cielo Filho et al. 2012, Havyarimana et al. 2013); this was the case of M. granulosa , S. opacula , and H. gerstaeckeri in the forests studied. The other species are relegated to the unfavorable areas (Ramade 2009), as was the case with G. opilionoides and P. femorata , two very rare species found only in the less degraded forest of Ngutadjap. It therefore seems necessary to reconstitute and conserve these different ecosystems in order to protect this forest biodiversity and its trophic structure.
Diversity and similarity. -In this work, species diversity increased with the level of human activity and use of forest resources: it was higher in the more anthropized forests of Zamakoe and Ongot and lower in the less anthropized forest of Ngutadjap. This result is presented by our cluster analysis based on species composition. Steer et al. (2009) also observed an increase in the invertebrate diversity, especially of diurnal Lepidoptera, with the level of forest degradation in Madagascar. Recently, Soliman et al. (2017) also reported significant differences between grasshopper community structures in moderately and highly disturbed sites in India, using one-way analysis of similarity. We therefore assume that invertebrate communities, especially of insects, are strongly influenced by increased human activities in forest ecosystems around the world; these invertebrates are recognized worldwide as indicative of the levels of natural habitat degradation (Clayton 2002, Gebeyehu and Samways 2003, Steck et al. 2007, Sirin et al. 2010, Chen et al. 2011).
This work was financially supported by a Rufford Small Grant (ID application: 19665-1) from the Rufford Foundation. We thank Dr. C.H.F. Rowell for proofreading the manuscript.
Almeida AV, Camara CAG (2008) Distribution of grasshoppers (Orthoptera: Acridoidea) in the Tapacura ecological station (Sao Lourenco da Mata, PE/Brazil).Brazilian Journal of Biology68: 21-24. https://doi.org/10.1590/S1519-69842008000100004
Amou'ou JP, Melingui A, Mounkam J, Tchepannou A (1985) Le Cameroun. Armand Colin, Paris.
Andersen AN, Ludwig JA, Lowe LM, Rentz DCF (2001) Grasshopper biodiversity and bioindicators in Australian tropical savannas: Responses to disturbance in Kakadu National Park.Austral Ecology26: 213-222. https://doi.org/10.1046/j.1442-9993.2001.01106.x
Armstrong AJ, van Hensbergen HJ (1997) Evaluation of afforestable montane grasslands for wildlife conservation in the north-eastern Cape, South Africa.Biological Conservation81: 179-190. https://doi.org/10.1016/S0006-3207(96)00034-1
Arya M K, Joshi PC, Vinod PB (2015) Species composition, abundance, density and diversity of grasshoppers (Insecta: Orthoptera) in a protected forest ecosystem in the Western Himalayas, India.International Journal of Fauna and Biological Studies2: 42-46. http://www.faunajournal.com/vol2Issue5/pdf/2-5-6.1.pdf
Basset Y, Aberlenc HP, Barrios H, Curletti G, Berenger JM, Vesco JP, Causse PA, Haug A, Hennion AS, Lesobre L, Marques F, O'Meara R (2001) Stratification and diel activity of arthropods in a lowland rainforest in Gabon.Biological Journal of the Linnean Society72: 585-607. https://doi.org/10.1111/j.1095-8312.2001.tb01340.x
Branson DH (2011) Relationships between plant diversity and grasshopper diversity and abundance in the Little Missouri National Grassland. Psyche 2011: 748635. https://doi.org/10.1155/2011/748635
Bray JR, Curtis JT (1957) An ordination of the upland forest communities of Southern Wisconsin.Ecological Monographs27: 325-349. https://doi.org/10.2307/1942268
Bronwyn AE (2013) Culturally and Economically Significant Insects in the Blouberg Region, Limpopo Province, South Africa. Dissertation, University of Limpopo, South Africa. http://hdl.handle.net/10386/1002
Brown DR (2006) Personal preferences and intensii[logical not]cation of land use: Their impact on southern Cameroonian slash-and-burn agroforestry systems.Agroforestry Systems68: 53-67. https://doi.org/10.1007/s10457-006-0003-9
Carlo HR, Help P, Herman MJ, Soetaert K (1998) Indices of diversity and evenness.Oceanis24: 61-87.
Chen Y, Li Q, Chen Y, Chen Z (2011) Effects of different land use on grasshopper diversity in lac agroecosystems.Terrestrial Arthropod Reviews4: 255-269. https://doi.org/10.1163/187498311X601704
Chinery M (1993) Insects of Britain and Northern Europe. Harper Collins Publishers, New York.
Cielo Filho R, Martins FR, Gneri MA (2012) Fitting abundance distribution models in tropical arboreal communities of SE Brazil.Community Ecology3: 169-180. https://doi.org/10.1556/ComEc.3.2002.2.4
Clayton JC (2002) The effects of clear cutting and wildfire on grasshoppers and crickets (Orthoptera) in an intermountain forest ecosystem. Journal of Orthoptera Research 11: 163-167. https://doi.org/10.1665/1082-6467(2002)011[0163:TEOCAW]2.0.CO;2
Colwell RK (2013) EstimateS: Statistical estimation of species richness and shared species from samples. Version 9. http://viceroy.eeb.uconn.edu/estimates
de Wasseige C, de Marcken P, Bayol N, Hiol Hiol F, Mayaux Ph, DescleIe B, Nasi R, Billand A, Defourny P, Eba'a Atyi R (2012) Les Forets du Bassin du Congo - EItat des ForeIts 2010. Office des publications de l'Union europeIenne, Luxembourg. https://doi.org/10.2788/48830
Dirsh VM (1956) The phallic complex in Acridoidea (Orthoptera) in relation to taxonomy.Transactions of the Royal Entomological Society of London108: 223-356. https://doi.org/10.1111/j.1365-2311.1956.tb02270.x
Dirsh VM (1961) A preliminary revision of the families and subfamilies of Acridoidea (Orthoptera, Insecta).Bulletin of the British Museum (Natural History) Entomology10: 351-419. https://doi.org/10.5962/bhl.part.16264
Dirsh VM (1965) The African Genera of Acridoidea. Cambridge University Press, Cambridge.
Dirsh VM (1966) Acridoidea of Angola.Publicacoes Culturais da Companhia de Diamantes de Angola74: 1-727.
Dirsh VM (1970) Acridoidea of the Congo (Orthoptera). Annales du Musee Royal d'Afrique Centrale, Tervuren, Serie in-8-Science Zoologiques-n[degrees] 182: 1-605.
Gangwere SK, Muralirangan MC, Muralirangan M (1997) The Bionomics of Grasshoppers, Katydids and Their Kin. CAB International, Wallingford.
Gebeyehu S, Samways MJ (2003) Responses of grasshopper assemblages to long-term grazing management in a semi-arid African savanna.Agriculture, Ecosystems & Environment95: 613-622. https://doi.org/10.1016/S0167-8809(02)00178-0
Gillon Y, Bourliere F (1983) The invertebrates of the grass layer. In: (Ed.) Ecosystems of the World (Vol.13). Tropical Savannas. Elsevier, Amsterdam, 289-311. http://www.documentation.ird.fr/hor/fdi:17364
Gockowski JJ (1996) Quelques donnees de l'enquete agricole dans les villages de recherche. Programme EPHTA en collaboration avec l'IRAD/ASB. IITA-Yaounde, Cameroon.
Guido M, Gianelle D (2001) Distribution patterns of four Orthoptera species in relation to microhabitat heterogeneity in an ecotonal area.Acta Oncologica22: 175-185. https://doi.org/10.1016/S1146-609X(01)01109-2
Hammer O, Harper DAT, Ryan PD (2001) PAST: Paleontological statistics software package for education and data analysis.Palaeontologia Electronica4: 1-9. http://palaeo-electronica.org/2001_1/past/issue1_01.htm
Havyarimana F, Bigendako MJ, Masharabun T, Bangirinama F, Lejoly J, Barima YSS, De Canniere C, Bogaert J (2013) Diversite et distribution d'abondances des plantes d'un ecosysteme protege dans un paysage anthropise: cas de la Reserve Naturelle Forestiere de Bururi, Burundi.Tropicultura31: 28-35. http://hdl.handle.net/2268/160257
Hollis D (1975) A review of the subfamily Oxyinae (Orthoptera: Acridoidea).Bulletin of the British Museum (Natural History) Entomology31: 189-234. https://doi.org/10.5962/bhl.part.29486
Hughes RG (1986) Theories and models on species abundance.The American Naturalist128: 879-899. https://doi.org/10.1086/284611
Hutcheson K (1970) A test for comparing diversities based on the Shannon formula.Journal of Theoretical Biology29: 151-154. https://doi.org/10.1016/0022-5193(70)90124-4
Jago ND (1967) A key to the grasshopper species (Orthoptera: Acridoidea) recorded from Ghana.Transactions of the Royal Entomological Society of London119: 235-266. https://doi.org/10.1111/j.1365-2311.1967.tb00511.x
Joubert L, Pryke JS, Samways MJ (2016) Positive effects of burning and cattle grazing on grasshopper diversity.Insect Conservation and Diversity9: 290-301. https://doi.org/10.1111/icad.12166
Kekeunou S, Membou DT, Tamesse JL, Oumarou Ngoute C (2017) Acrididea diversity in degraded areas of higher mountains in West Cameroon.African Entomology25: 239-243. https://doi.org/10.4001/003.025.0239
Kemp WP, Harvey SJ, O'Neill KM (1990) Patterns of vegetation and grasshopper community composition.Oecologia83: 299-308. https://doi.org/10.1007/BF00317552
Kevan DKM (1975) A revision of the genus Taphronota Stal, 1873 (Orthoptera; Acridoidea; Pyrgomorphidae). Publicaoes Culturais da Companhia de Diamantes de Angola (1974) 88: 79-150.
Latchininsky AV (2008) Grasshopper outbreak challenges conservation status of a small Hawaiian Island.Journal of Insect Conservation12: 343-357. https://doi.org/10.1007/s10841-008-9143-8
Latchininsky A, Gapparov FA (1996) Les consequences du dessechement de la mer d'Aral sur la situation acridienne dans la region.Secheresse7: 109-113.
Latchininsky A, Sword GA, Sergeev MG, Cigliano MM, Lecoq M (2011) Locusts and grasshoppers: Behavior, ecology and biogeography. Psyche 2011: 578327. https://doi.org/10.1155/2011/578327
Lecoq M (1980) Cles de determination des acridiens des zones sahelienne et soudanienne en Afrique de l'Ouest. Bulletin de l'Institut Fondamental d'Afrique Noire (1979) 41/A/3: 531-595.
Marcon E (2015) Mesures de la biodiversite. UMR Ecologie des forets de Guyane, Kourou. http://hal-agroparistech.archives-ouvertes.fr/cel-01205813v4
Mbenoun Masse PS, Nzoko Fiemapong AR, VandenSpiegel D, Golovatch IS (2017) Diversity and distribution of millipedes (Diplopoda) in the Campo Ma'an National Park, southern Cameroon.African Journal of Ecology56: 73-80. https://doi.org/10.1111/aje.12418
Mertens B, Neba SG, Steil M, Tessa B, Mendomo Biang JD, Leach A, Mbouna D, Mboua P, Feuzing A, Methot P, Minnemeyer S, Douard P, Ngilambi H (2012) Atlas Forestier Interactif du Cameroun. World Resources Institute, Washington DC.
Mestre J, Chiffaud J (2009) Acridiens du Cameroun et de Republique centrafricaine (OrthopteraCaelifera). Supplement au catalogue et atlas des acridiens d'Afrique de l'Ouest. http://acrida.info/PDF2009/Catalogue-Acridiens-2009.pdf
More SV, Nikam KN (2016) Studies on grasshoppers (Orthoptera) in Tilari forest, Chandgad, Kolhapur district of Maharashtra (India).International Journal of Recent Scientific Research7: 9457-9460. http://www.recentscientific.com/sites/default/files/4578._0.pdf
Ndoye O, Kaimowitz D (2000) Macro-economics, markets and the humid forests of Cameroon, 1967-1997.Journal of Modern African Studies38: 225-253. https://doi.org/10.1017/S0022278X00003347
Otte D (1976) Species richness patterns of new world desert grasshoppers in relation to plant diversity.Journal of Biogeography3: 197-209. https://doi.org/10.2307/3038010
Raghavender B, Vastrad AS (2017) Changing scenario of short horned grasshopper diversity in agriculture and forest ecosystems in Dharwad.Journal of Entomology and Zoology Studies5: 268-272. http://www.entomoljournal.com/archives/2017/vol5issue2/PartD//5-1-138-321.pdf
Ramade F (2009) Elements d'ecologie: Ecologie fondamentale (4th edn). Dunod.
Saha HK, Haldar P (2009) Acridids as indicators of disturbance in dry deciduous forest of West Bengal in India.Biodiversity and Conservation18: 2343-2350. https://doi.org/10.1007/s10531-009-9591-9
Samways MJ, Gangwere SK, Muralirangan MC, Muralirangan M (1997) Conservation biology of Orthoptera. In: (Eds) The Bionomics of Grasshoppers, Katydids and their Kin.CAB International, Wallingford, 481-496.
Santoir C, Bopda A (1995) Atlas regional Sud-Cameroun. Orstom/Minrest, Paris/Yaounde. http://www.documentation.ird.fr/hor/fdi:010004189
Schmidt GH, Ibrahim NM, Abdallah MD (1991) Toxicological studies on the long-term effects of heavy metals (Hg, Cd, Pb) in soil on the development of Aiolopus thalassinus (Fabr.) (Saltatoria: Acrididae).Science of the Total Environment107: 109-133. https://doi.org/10.1016/0048-9697(91)90254-C
Scott DM, Brown D, Mahood S, Denton B, Silburn A, Rakotondraparany F (2006) The impacts of forest clearance on lizard, small mammal and bird communities in the arid spiny forest, southern Madagascar.Biological Conservation127: 72-87. https://doi.org/10.1016/j.biocon.2005.07.014
Seino RA, Dongmo TI, Ghogomu RT, Kekeunou S, Chifon RN, Manjeli Y (2013) An inventory of short horn grasshoppers in the Menoua Division, West Region of Cameroon.Agriculture and Biology Journal of North America4: 291-299. https://doi.org/10.5251/abjna.2013.4.3.291.299
Sergeev MG (1998) Conservation of orthopteran biological diversity relative to landscape change in temperate Eurasia.Journal of Insect Conservation2: 247-252. https://doi.org/10.1023/A:1009620519058
Sirin D, Eren O, Ciplak B (2010) Grasshopper diversity and abundance in relation to elevation and vegetation from a snapshot in Mediterranean Anatolia: Role of latitudinal position in altitudinal differences.Journal of Natural History44: 1343-1363. https://doi.org/10.1080/00222930903528214
Soliman MM, Haggag AA, El-Shazly MM (2017) Assessment of grasshopper diversity along a pollution gradient in the Al-Tebbin region, South Cairo, Egypt.Journal of Entomology and Zoology Studies5: 298-306.
Song H (2010) Grasshopper systematics: Past, present and future.Journal of Orthoptera Research19: 57-68. https://doi.org/10.1665/034.019.0112
Spungis V (2007) Fauna and ecology of grasshoppers (Orthoptera) in the coastal dune habitats in Ziemupe Nature Reserve, Latvia.Latvijas entomologs44: 58-68. http://leb.daba.lv/44-sp1.pdf
Steck CE, Burgi M, Bolliger J, Kienast F, Lehmann A, Gonseth Y (2007) Conservation of grasshopper diversity in a changing environment.Biological Conservation138: 360-370. https://doi.org/10.1016/j.biocon.2007.05.001
Steer MD, Vater A, McCann-Wood S (2009) The effect of forest degradation on the species richness and diversity of a diurnal Lepidoptera community in Northern Madagascar. Frontier - Madagascar Environmental Research, Report 22. The Society for Environmental Exploration, London. http://frontier.ac.uk/Publications/Files/2010_11_23_13_51_51_235.pdf
Tadu Z, Djieto-Lordon C, Babin R, Yede , Messop-Youbi EB, Fomena A (2013) Influence of insecticide treatment on ant diversity in tropical agroforestry system: Some aspect of the recolonization process.International Journal of Biodiversity and Conservation5: 832-844. https://agritrop.cirad.fr/572130/1/document_572130.pdf
Tadu Z, Djieto-Lordon C (2014) Ant diversity in different cocoa agroforest habitats in the centre region of Cameroon.African Entomology22: 388-404. https://doi.org/10.4001/003.022.0219
Tchatchou B, Sonwa DJ, Ifo S, Tiani AM (2015) Deforestation and Forest Degradation in the Congo Basin: State of Knowledge, Current Causes and Perspectives. Occasional paper 144, Center for International Forestry Research, Bogor. https://doi.org/10.17528/cifor/005894
Torrusio S, Cigliano MM, De Wysiecki ML (2002) Grasshopper (Orthoptera: Acridoidea) and plant community relationships in the Argentine pampas.Journal of Biogeography29: 221-229. https://doi.org/10.1046/j.1365-2699.2002.00663.x
Westphal E, Embrechts J, Mbouemboue P, Westphal-Stevels JMC (1981) L'agriculture autochtone au Cameroun; les techniques culturales, les sequences de culture, les plantes alimentaires et leur consommation. Miscellaneous papers 20-Landbouwhogescool, Wageningen.
Yelland PM (2010) An Introduction to Correspondence Analysis.The Mathematica Journal12: 1-23. https://doi.org/10.3888/tmj.12-4
Zhang ZQ (2011) Animal biodiversity: An outline of higher-level classification and survey of taxonomic richness.Zootaxa3148: 1-237.
[see PDF for image]
Supplementary material 1: Data type: plant species richness
Explanation note: Effect of anthropogenic pressures on floristic composition from the forests of three localities of southern Cameroon.
This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.
Authors: Author: Charly Oumarou Ngoute, Sevilor Kekeunou, Michel Lecoq, Armand Richard Nzoko Fiemapong, Philene Corine Aude Um Nyobe, Charles Felix Bilong Bilong
 Laboratory of Zoology, Faculty of Science, University of Yaounde 1, Cameroon.
 CIRAD, Montpellier, France.
 Laboratory of Parasitology and Ecology, Faculty of Science, University of Yaounde 1, Cameroon.
Corresponding author: Charly Oumarou Ngoute (firstname.lastname@example.org)
Academic editor: Alina Avanesyan
|Printer friendly Cite/link Email Feedback|
|Author:||Oumarou Ngoute, Charly; Kekeunou, Sevilor; Lecoq, Michel; Nzoko Fiemapong, Armand Richard; Um Nyobe,|
|Publication:||Journal of Orthoptera Research|
|Date:||Feb 3, 2020|
|Previous Article:||Acridid ecology in the sugarcane agro-ecosystem in the Zululand region of KwaZulu-Natal, South Africa.|