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Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Frequent alteration in land cover often leads to decreased stability of ecosystems which can also increase the vulnerability of rural communities to externalities of environmental change. This study carried out in parts of the coast of southwestern Nigeria utilized topographic base maps and two-time Landsat TM imageries to assess the trend in land cover changes and ecosystems degradation for the three time periods 1965, 1986 and 2001. Remote sensing, geographic information systems and landscape pattern analysis were employed for data processing and analysis. The focus of the analysis was on land cover change, land degradation, and changes in landscape pattern resulting from interplay of natural and anthropogenic drivers. The results show increased trend in human-induced land cover change with concomitant severe negative impacts on ecosystems and livelihoods. About 98,000ha (30% of the area) was seriously degraded as at 2001. About 33,000ha (10%) was under permanent saline water inundation with about 21 communities already dislocated. Loss of fragile ecosystems including marshland (from 7.7% in 1965 to 1% in 2001) and mangrove (from 14.6% in 1965 to 3.1% in 2001) was intense, while over 300 ponds/small lakes which are important for the local fishing economy have disappeared. About eighteen communities were also dislocated by erosion in a section around the southeastern parts of the coastline. Landscape metrics generated, suggested increased ecosystems perturbation and landscape fragmentation. The paper also discussed the implications of these rapid changes for ecosystems stability, food security and sustainable rural livelihoods in the area. [ABSTRACT FROM AUTHOR]

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Tree species population dynamics were studied in a 0.25-ha secondary rain forest plot which was accidentally burnt in 1983 by a severe ground fire. The effect of the fire on tree species in the plot was assessed after 14 months in 1984 and 14 years in 1997 to establish the changes in tree species composition and structural characteristics of the plot after the fire. The present study investigated the changes in species composition, mortality, recruitment rates and some structural characteristics of the plot 18 years after the fire. The results from this study were compared with previous studies in the plot. Tree species richness of the plot (37 per 0.25 ha in 1983), which increased to 40 and 71 species 1 and 14 years respectively after the fire dropped to 63 species 18 years after. Fifteen species, which were not originally present before the fire, are established and abundant now. Ten woody species, each of which were originally present and which established 1 year after the fire have died. Stem density increased from 3192 trees ha−1 1 year to 10,064 trees ha−1 18 years after the fire. Basal area increased while species diversity, which increased to 3.41 14 years after, decreased to 3.07 18 years after. The annual mortality rate was 2.1% 14 years after and annual recruitment rates were 74.5% year−1 and 35.7% year−1 1 and 18 years after the fire, respectively. These observations give insight to secondary forest succession after fire. Résumé On a étudié la dynamique des populations d'arbres dans une parcelle de 0,25 ha de forêt pluviale secondaire qui a été brûlée accidentellement en 1983. L'effet du feu sur les espèces d'arbres contenues dans la parcelle a étéévalué après 14 mois, en 1984, et après 14 ans, en 1997, pour déterminer les changements de la composition des espèces d'arbres, et les caractéristiques structurelles de la parcelle après le feu. La présente étude analyse les changements de la composition des espèces, la mortalité, le taux de régénération et quelques caractéristiques structurelles de la parcelle 18 ans après l'incendie. Les résultats sont comparés à ceux des études précédentes au même endroit. La richesse en espèces de la parcelle (37 pour 0,25 ha en 1983) qui était passée à 40 un an après le feu et à 71 après 14 ans, s'est réduite à 63 espèces après 18 ans. Quinze espèces qui n’étaient pas présentes avant l'incendie sont maintenant bien établies et abondantes. Dix espèces ligneuses qui étaient présentes originellement et qui étaient installées un an après le feu ont disparu. La densité des pousses a augmenté de 3.192 arbres/ha, un an après le feu, à 10.064 arbres/ha après 18 ans. La surface terrière a augmenté tandis que la diversité des espèces, qui avait aussi augmenté jusqu’à 3,41, a diminuéà 3,07 18 ans plus tard. Le taux de mortalité annuel était de 2,1%, 14 ans après le feu, et le taux de régénération était de 74,5% et de 35,7% respectivement un an et 18 ans après l'incendie. Ces observations donnent un aperçu de l’évolution d'une forêt secondaire après un feu. [ABSTRACT FROM AUTHOR]

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article presents information on a study on seasonal variations in distribution and catch composition of migratory fishes Penaeus and Macrobranchium in Badagry Creek, Nigeria. It states that bioecology of migratory fishes is important for aquatic food web of fisheries. In the present study the variations in physical and chemical properties of water and the fish populations was studied. In the study a significant variation in the catch compostion of P. notialis and M. macrobrachion was noted.

The article presents information on a survey on the fungi found on Red mangrove and White mangrove plants in deltaic region of Rivers State, Nigeria. The study analyzed the several species of mangroves in the selected region to isolate and identify fungi on various plant parts. The article includes several charts that list various pathogenic fungal species isolated from mangrove plants of various regions, including Pestalotia dichaeta, Fusarium sp., and Phomopsis sp.

Studies the diet of python sebae with consideration on its adaptation to altered habitats in suburban and natural habitats of southern Nigeria. Phyton size; Local time of phyton sighting; Similarity of food preferences of python from suburban and natural habitat; Time of suburban phyton predatory events; Python activity patterns.

Rainfall interception by forest trees, pH, alkalinity, total suspended and dissolved solids of incident rainfall, stemflow and throughfall and the effect of tree species in these parameters were investigated in three open sites and a secondary rain forest at Ile-Ife, Nigeria, in 1994 and 1995. The tree species Blighia sapida, Holarrhena floribunda and Piptadeniastrum africanum intercepted different proportions of incident rainfall, 1.6, 39.4, and 7.4%, respectively. The pH of stemflow was higher than that of throughfall and the pH of both was always higher than that of incident rainfall. The total suspended solids were higher at the beginning and towards the end of the rainy season. The total dissolved solids concentration in all rainfall fractions was highest at the early rains and during the heavy rain months, especially in throughfall and stemflow. The total suspended and dissolved solids concentration of stemflow was higher than that of throughfall and those of both were higher than that of the incident rain. Total alkalinity of incident rainfall and throughfall decreased, while that of stemflow increased with increase in rainfall. There were significant differences in the alkalinity of stemflow and throughfall under the crowns of the tree species. [ABSTRACT FROM AUTHOR]