Deadwood; snags or downed coarse are important habitat features for many forest-dwellers. They influence ecological activities and biodiversity. This study reported on the ecological role of snags and downed coarse as habitat providers. The research was conducted at Kanawa forest reserve. Systematic random sampling method was employed to lay 4,000m line transects (500m each) across the forest edge (FE) and core forest (CF) of the reverse. On each transect, five 20m x 20m plots were established at 100m interval to assess the deadwood, their colonizers and relationship. Different animal species were recovered using snags as their prepared home or hiding place. Salamander (31%) was found in significantly greater frequencies in the core forest as colonizer. Downed coarse accommodate diverse animal species with only one plant, Chick wee. Forest edge has the transect with higher numbers of colonizers, whereas core forest has the optimum percent of downed coarse. On colonization and relationship, the interaction is either as saprophyte, use as niches or habitat. The organisms are Reptiles, Isopoda, Hymenoptera and Herbs. Among the animate thing, forest edge possess more and diverse colonizers.

This study examined the integration of Remote Sensing and Geographic Information System (RS/GIS) for analyzing land use and land cover dynamics in Gombe Metropolitan, the Gombe State capital for the period 1976 to 2016. Land sat (TM) images of 1976, 1996and 2016 were used. The study employed supervised digital image classification method using Erdas Imagine 9.2 and Arc GIS 10.5 software and classified the land use into undisturbed vegetation, sparse vegetation, Settlements, Farmlands, Rock outcrops, Bare surfaces. The images were analyzed via georeferencing, image enhancement, image resampling and classification. The results obtained show an increasing settlements (from 0.36% - 4.01%) and farmlands (from 24.8% - 51.2%), over a decreasing of other LULC classes (bare surfaces, undisturbed and sparse vegetation, and rocky outcrops) for the time period of 1976 to 2016. These results could help city planners and policy makers to attain and sustain future urban development. It is therefore recommended that encouragement should be given to people to build towards the outskirts, like New mile 3 and Tumfure, etc through the provision of incentives and forces of attraction that is available at the city center in these areas to avoid the problem of overcrowdings.

The structure and properties of tropical stream food webs were investigated in nine second and third order streams, three in continuous sub-montane forest, three in tea plantations and three in maize fields.All were located on the Mambilla Plateau, north-east Nigeria.Components of all trophic levels (e.g., fine particulate organic matter [FPOM], coarse particulate organic matter [CPOM], algae, benthic invertebrates and fish) were sampled, and analysed by examination of gut contents and using stable isotopes techniques.Gut contents of key invertebrate species were categorised into eight types of food items: filamentous algae, diatoms, fungi, CPOM ≥ 1 mm (usually leaf litter and wood fragments), FPOM 1 mm (often amorphous detritus) and animal parts.Several food web properties were calculated and a basic food web was constructed using density data.Invertebrate species richness and density were higher in forest than in tea plantations and maize fields.Community and dietary analyses revealed that streams in the tea plantation and maize fields had simpler food webs incorporating fewer species and shorter food chains than those in continuous forest.However, potamonautid crabs (macroconsumers) and fish were present in all streams.Significant differences occured in three food web parameters calculated for streams in catchments differing in land uses: web size (ANOVA F2, 6 = 15.509,P = 0.004), predator prey ratio (ANOVA F2, 6 = 17.337,P = 0.003), standing biomass of invertebrates (AFDM); CPOM mass (ANOVA F2, 6 = 8.727, P = 0.016) and algal (ANOVA F2, 6 = 37.599, P = 0.001).Stable isotope analysis revealed that primary consumers assimilated a mixture of autochthonous and allochthonous carbon resources (CPOM and algae) in all streams.

Benthic invertebrate communities have been shown to respond to habitat degradation as a result of land use changes. Although these changes have been well documented in temperate regions, their effects in the tropics have been poorly documented particularly where land use activities differ markedly (e.g., tea, maize and plantations). A survey 55 1st and 2nd order highland tropical streams, across four land use categories, ranging from continuous tropical montane rain forest to intensive crops and pasture. Streams were sampled in the tropical dry season (October–March) for physico-chemical parameters and components of the biological community, (i.e., fine particulate organic matter [FPOM], coarse particulate organic matter [CPOM], algae and benthic invertebrates). Catchment riparian conditions and human water use activities were used to generate a multivariate land use intensity gradient score. Temperatures in pasture streams were warmer than forest streams (up to 25oC) and dissolved oxygen levels frequently low (15–79%). However, physico-chemical conditions did not show any clear patterns across land uses categories. In contrast, benthic invertebrate communities showed strong response with the highest taxonomic diversity in continuous forest streams (mean 20 taxa) and the lowest in streams with intensive crops (e.g., cabbage crops, mean 8 taxa). Marked changes were found in invertebrate communities with several taxa occurring primarily in forested streams (e.g., the mayflies Heptageniidae and Oligoneuriidae and brachyuran crabs). Tropical land use farming (e.g., tea, maize, cabbage) have significant impacts on the benthic invertebrate assemblages of highland streams in Nigeria. However, not all crop and plantation streams had highly impacted communities because some have wider riparian buffer zones. This study further highlight the importance of conservation and management of montane forest fragments in these regionsKeywords: Tropical, Nigeria, highland, benthic invertebrates, land use, degradation

The need for new compounds active against malaria parasites is made more urgent by the rapid spread of drug-resistance to available anti-malaria drugs.The crude methanolic extract of Albizia chevalieri leaves was investigated for its antimalarial activity against Plasmodium berghei (NK65) during early and established infections.The level of parasitaemia, mean survival time and weight variation of rats were used to determine the antimalarial activity of the extract.The Phytochemical screening of the crude extract were evaluated to elucidate the possibilities of its antimalarial effects.The safety of the extract was also investigated in rats of both sexes by the acute oral toxicity limit test.The leaf extract demonstrated significant (P<0.01)dose dependent activity against the parasite in the suppressive and curative, and also had repository activity.The antimalarial effect of A.chevalieri is comparable to that of artermether.The leaf extract also prolonged the survival time of the infected rats.The LD50 of the plant extract was established to be >3000mg/kg body weight in rats.The results showed that the leaf extract of the plant has potential antiplasmodial activity, which can be exploited in malaria therapy.Accordingly with further studies, this plant could serve as a potential source of new and novel antimalarial drug for the control of malaria.

In this paper, we utilise the newly developed method K-Disjoint Maximum Convex Sum Problem (K-DMCSP) in a real-life application, which investigates the effects of land use changes on benthic stream communities in highland tropical streams of Nigeria. A collaboration between computer scientists and freshwater biologists was established to implement and examine the robustness of this approach compared to a traditional method that used rectangular shape in the K-Disjoint Maximum Sub-Array algorithm (K-DMSA). This novel approach uses the K- DMCSP, which utilises a convex shape as compared to a rectangular shape. In the above comparison the new approach using the convex shape optimises the sum and yields more accurate and precise results. This is because using the rectangular shape is limiting and is therefore not flexible enough to cover various sets of data distributions. The new approach was applied to data that were collated from 55 tropical highland streams on the Mambilla Plateau, Nigeria to investigate the interactions between substrate index or dissolved oxygen and temperature with number of macroinvertebrates (taxa). The K-DMCSP method located the K-maximum threshold values. This was achieved by defining the substrate index or dissolved oxygen associated most with the temperature by maximising the sum of elements of a selected portion of a two dimensional array. The K-DMCSP successfully detected the various temperatures between the different categories of the substrate index or dissolved oxygen, and how those variables affect numbers of macroinvertebrates. Furthermore, applying the algorithm revealed that the number of macroinvertebrates differs according to land use (e.g. forestry and agriculture). The new method used in this paper is encouraging in its capability to find the relationship between various environmental parameters and macroinvertebrate distribution and diversity. This method can potentially be applied to other real-life applications requiring finding associations between different parameters.