African Journal of Ecology and Ecosystems

African Journal of Ecology and Ecosystems Vol.  2 (3) pp. 107-117, March, 2015. © International Scholars Journals

Full Length Research Paper

Utilitarian separations of woody species, Proxy of Ecological versatility and procurement for Forest administration

*Senait Gelila Defar, Molatu Bikila and Mamo T. Akilu

Department of Ecology and Natural Resource Management, Haramaya University, Dire Dawa, Ethiopia.

E-mail: prof. [email protected] 

Accepted 02 February, 2015

Abstract 

The natural forests in north western Ethiopia have been dwindling at an alarming rate. However, church forests are found as a spot in each community serving as unique and conspicuous in situ conservation of indigenous species. Five church forests with adjacent degraded forests were surveyed to investigate the functional distance and diversity. Fifty woody species were identified both from the church and adjacent degraded forests and have 34 species in common (S_j = 0.68). Eleven new species were recorded in the adjacent degraded forest, but five species which were found in the church forest disappeared. The average functional distances between woody species were 22.3 ± 14.4 (mean ± SD) and 23.8 ± 17.0 for church and adjacent degraded forests, respectively. Dominant woody species were functionally dissimilar. Functional distances between 10 minor of the church and 10 dominant of adjacent degraded forest species were significantly different (² = 12.24, P = 0.01), suggesting that minor species have offered insurance. Passenger species and some of the dominant species in the church forest have also offered insurance. Functional distance which is a cumulative effect of functional attributes is a proxy for ecological elasticity to disturbances and helps in forest management decisions.

Key words: Church forests, degraded forests, ecosystem, functional attributes, relative abundance, resilience.

African Journal of Ecology and Ecosystems Vol.  2 (2) pp. 103-106, February, 2015. © International Scholars Journals

Full Length Research Paper

Environmental assessment of forest soils in Azerbaijan

Vagif E. Aiyev

Department of Soil Science, Faculty of Agriculture, Khazar University, Baku, Azerbaijan.

Email: [email protected]

Accepted 22 January, 2014

Abstract 

While afforestation is relevant in the study of the ecological state of forest soil, analyses of the soil samples and valuation of the soil types to obtain final yield class is important. Within the National State Afforestation Program, as the research object, the south-east slope of the big Caucasus has been chosen for checking up soils under woodland and woodless areas. After having taken soil samples in this zone, these samples were analyzed and the amount of humus, nitrogen, phosphorus and absorbed matters sum (AMS) have been determined for a hectare (t/ha). Formula (1) was applied to determine the soil fertility factor and mechanical composition quantity (t/ha). By the traditional soil valuation method, proposed by an academician, G. Sh. Mammadov, in comparison with the selected etalon soil type, other soil valuations were given by points. Formula (2) was used to obtain the final points of the soil type and subtypes: 1) The total amounts (t/ha) of the soil types and subtypes which were determined based on formula (1). As summary of the ecological estimation, the final main yield class points of soils was established due to calculation by formula (2) for all soil type and subtypes under woodland and woodless areas in Shamakhi region, situated in the very natural zone. The results obtained from the experiments and calculations, showed the present ecological state of the woodland and woodless soils, their fertility factor and mechanical composition.

Key words: Ecological estimation, main yield class, soil ecology, valuation of soil, valuation point, ecological safety, forest protection.

African Journal of Ecology and Ecosystems Vol.  2 (2) pp. 095-102, February, 2015. © International Scholars Journals

Full Length Research Paper

Evaluating the outcomes of small–scale cutting of mangrove forests in the ecosystem

*Simon E. Ahidjo, Ephraim R. Hayatou and Peter L. Ayang

Department of Environmental Science, University of Ngaoundéré, Ngaoundéré, Cameroon.

E-mail: [email protected] 

Accepted 16 January, 2015

Abstract 

One of the most universal forms of resource-use in the tropics is small-scale wood exploitation; but ecologists are only starting to study its effects. This paper examines the effects of small-scale wood harvesting on forest structure and composition of mangrove forests. A stratified sampling method was used to select the sample zone. The forest characteristics were assessed by employing the quadrat/census plot method (Cintron and Schaeffer, 1984). To assess canopy structure, plot perimeter was used as a basis for line intercept sampling (Lertzman et al., 1996). Two-thirds of all canopy gaps were caused by human activities and this might have dramatic effects on regeneration because there were significantly more seedlings in canopy gaps compared with closed canopy areas. Rhizophora was the dominant species and formed a virtually monospecific stand in the coastline zone with a gradual transition to a mixed forest of Laguncularia, Avicennia and Rhizophora. Ecological characteristics such as mean tree density, seedling density, mean diameter at breast height, basal areas and gap sizes differed among seaward, middle and landward zones. The findings from the present study highlight that the ecological effect of small scale wood exploitation is a potential threat to mangrove forest ecosystem health.

Key words: Cameroon, mangrove ecology, forest ecosystem health.

African Journal of Ecology and Ecosystems Vol.  2 (1) pp. 083-094, February, 2015. © International Scholars Journals

Full Length Research Paper

Utilization of macroinvertebrate gathering to evaluate the natural integrity of Nyando Wetlands, Kenya

Jomo Awori Odinga

Department of Biological Sciences, University of Nairobi, Nairobi, Kenya.

Email: [email protected]

Accepted 07 January, 2015

Abstract 

This study aimed to investigate changes in macroinvertebrate assemblage within Nyando wetlands and developed an index of biotic integrity for monitoring human disturbances. Triplicate macroinvertebrate samples were collected monthly for seven months using a scoop net. They were sorted live, counted and identified to genus level. Water samples for nutrients were collected and analyzed using standard methods. Physico-chemical parameters were taken in situ using electronic meters. Macroinvertebrates were analyzed for richness, diversity, dominance and abundance. Abundance was correlated with physico-chemical parameters. Kruskal-Wallis test was used to test spatial differences in macroinvertebrate community. Metrics for index of biotic integrity were chosen, tested, and a 5, 3, 1 scoring criteria was used. A total of 45 genera were identified and Kruskal-Wallis test analysis revealed significant spatial differences in macroinvertebrate abundance. Repeated measures ANOVA showed significant spatio-temporal differences. Tolerant macroinvertebrates were abundant at the disturbed sites whereas intolerant taxa showed a strong negative correlation with nutrient levels. Sites with higher disturbance recorded a total index score far below the reference site score. The results indicated that macroinvertebrates in Nyando wetlands can be used to monitor its ecological integrity. The IBI developed should be used to protect the lake from eutrophication.

Key words: Human disturbance, water quality, index of biotic integrity.

African Journal of Ecology and Ecosystems Vol.  2 (1) pp. 075-082, January, 2015. © International Scholars Journals

Full Length Research Paper

Plant groups and tree species relationship in a Miombo Ecosystem in the Lake Rukwa bowl, Southern Tanzania: Implications for protection

*Jakaya Hassan, Salmin Warioba and Benjamin E. Lowassa

Department of Forest Biology, Faculty of  Agriculture, University of Dar es Salaam, Dar es Salaam, Tanzania.

E-mail: [email protected]

Accepted 22 December, 2014

Abstract

This study assessed the plant communities and species associations in the eastern Miombo woodlands eco-region of the Lake Rukwa basin southern Tanzania. Information was collected from 288 temporary sample plots in 32 sampling sites established randomly in the area and covering as much variation in the landscape as possible. Detailed analysis of the vegetation identified six tree communities of conservation importance, which included Brachystegia boehmii-Pericopsis angolensis woodland, Julbernardia globiflora woodland, Combretum molle-Sclerocarya birrea-Combretum zeyherii-Acacia seyal var fistula woodland, Bridelia cathartica-Diospyros mespiliformis woodland, Brachystegia bussei-Pterocarpus tinctorius woodland and Brachystegia microphylla-Isoberlinia tomentosa-Hymenocardia acida- Syzygium owariense woodland. Majority of the described plant communities are typical of Miombo ecosystems dominated by trees belonging mainly to the genera Brachystegia and Julbernardia. A mixture of non-legume species but typical of the Miombo ecosystem, however, dominates two out of six described plant communities. Apparently, there is high variability of plant communities in the Miombo ecosystem of southern Tanzania, an indication of the diverse nature of the Miombo ecosystem, also, an implication of high species diversity. This documentation on the patterns of species assemblages is the beginning of unveiling the diversity of assemblage of species in dry forest ecosystems which occupy a wide area in the region. These associations are important targets for conservation and monitoring vegetation changes in this ecosystem.

Key words: Miombo ecosystem, plant communities, species associations.

African Journal of Ecology and Ecosystems Vol.  2 (1) pp. 071-074, January, 2015. © International Scholars Journals

Full length Research paper

Ichthyofauna differing qualities of Lake Asejire: Ecological ramifications

Ramah J. Marvis

Department of Earth and Environmental Sciences, Benson Idahosa University, Benin City, Nigeria.

Email: [email protected] 

Accepted 19 December, 2014

Abstract 

The natural diversity of most aquatic systems has witnessed various changes in stock diversity and abundance resulting from structural changes in habitat, food composition and uncontrolled exploitation. These have altered the ecology of the fish resources with the disappearance of some species and dominance of others. This study seeks to identify the ecological implication of the stock diversity and abundance in Lake Asejire. Lake Asejire is a 525 ha man-made lake on river Osun one of the major rivers that drain the western part of Nigeria. Fish samples were collected for a period of 24 months using gillnets of between 25 and 187.5 mm mesh sizes. Data obtained were analyzed using inferential statistics and descriptive analysis of means, frequencies and percentages. Seventeen families identified and grouped into trophic levels. Herbivores were 63.03 and 60.35%; carnivore 31.05 and 30.65% and omnivores were 5.91 and 8.99% by biomass in the first and second year respectively. The herbivores were dominated by the cichlids, heterotis and cyprinids; carnivores by bagrids, characids, channids and Lates while mormyrids, synodonts and clarids constitute the omnivores. Seasons had no effect on the population and number of the carnivores. The carnivore to herbivore ratio (F/C) was 1.33 and 0.9 by number and 1.7 and 1.33 by biomass; this is of concern as this could pose a threat to ecological balance. It is recommended among others that fishing pressure should be increased on carnivores and more herbivores be injected to the environment to prevent the collapse of the fisheries.

Key words: Fishing pressure, trophic levels, diversity, ecological balance, lake.