Wyniki wyszukiwania - Biblioteka Nauki

1

The influence of riparian vegetation on the distribution and abundance of bats in an African savanna

100%

Monadjem A. , Reside A.

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tom 10

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nr 2

EN

Riparian habitats are known to be important for bats across the world, however this is largely unstudied in Africa. We investigated the community structure of bats in riparian areas and the surrounding savanna landscape in Swaziland's lowveld using mist nets and a harp trap. We found riparian sites overall had higher bat activity, diversity, species richness and abundance. One species (Epomophorus wahlbergi) accounted for 52.6% of captures. Seasonality had no effect on overall captures, nor did distance from nearest riparian habitat for savanna sites. Echolocation guilds were correlated with vegetation characteristics, with CF (constant frequency), FM (steep frequency-modulated) and FM-QCF (broadband FM) bats more frequently captured at sites with denser undergrowth than QCF (quasi-constant frequency or narrowband FM) bats; conversely, QCF bats were more frequently caught at sites with lower canopy cover than other bats. Our findings suggest that although bats discriminate between microhabitats, they do not respond to larger-scale habitat features in the way that other taxa, such as birds, are found to. In conclusion it appears that riparian areas are important foraging sites for bats within African savannas.

2

Comparative non-linear regression - case of infiltration rate increase from upstream in valley

100%

Keita A. , Yacouba H. , Hayde L. G. , Schultz B.

International Agrophysics

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2014

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tom 28

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nr 3

EN

In Tropical Savannah flooded valley soils, very low infiltration rates often result in acidic conditions favourable to high concentrations of metallic ions, toxic for rice. Determination of the under-phreatic infiltration rate is important in drainage design to reclaim degraded soils. Several studies have addressed the mapping of the infiltration rate. Yet, its relationship with the toposequence of the valley is not clarified. This paper has investi- gated such a possibility, examining the case of the irrigated rice valley of Tiefora, Burkina Faso. Nine boreholes – from 1 to 5 m deep – were implemented from upstream to downstream. The Lefranc permeability test of the under-phreatic level in water- logged soils – used when the impervious layer is close to soil sur- face or absent – was conducted. First, a comparative regression was applied to the data, including all the parameters of the regression curves. In the case of dissimilarity of the infiltration processes, the comparison focused on the final permeability. The results show a permeability increase from upstream (0.10±0.10 cm h -1 ) to down- stream (greater than 20±10 cm h -1 in some places). Taking into account such a permeability increase in the subsurface drainage system design would result in implementation of more efficient and cost effective systems.

3

Parasitism of ectoparasitic flies on bats in the Northern Brazilian cerrado

84%

Santos C. L. C. , Pereira A. C. N. , Bastos V. J. C. , Graciolli G. , Rebelo J. M. M.

Acta Parasitologica

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2013

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tom 58

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nr 2

EN

In this work we record the highest number of bat flies species among those already performed in the Brazilian cerrado and discuss the associations and patterns of parasitism of these species and their hosts. A total of 1,390 ectoparasitic flies were collected, belonging to 24 species of Streblidae and one of Nycteribiidae, parasitizing 227 bats of 15 species. Among the species found, the presence of Trichobius sp. on Lonchophylla mordax and the first occurrence of Hershkovitzia sp. on Thyroptera devivoi are highlighted. Lophostoma species presented the highest proportion of individuals with infracommunities and the highest values of parasitological indexes. The high number of bat fly species and hosts, as well as the high values for rates of parasitism and infracommunities, suggests that this area of cerrado has good shelter conditions for these species. The abundance of species and high rates of parasitism detracts from the hypothesis that a higher mean intensity of ectoparasites results from lower competition among flies for hosts in areas with lower ectoparasite species richness. Biogeographical and historical factors of host populations, besides the number of host species and individuals sampled, may contribute to species number and intensity of parasitism.

4

Field evaluation of two aqueous plant extracts on water melon Citrullus lanatus (Thumb) insect pests in Northern Guinea savannah of Nigeria

84%

Degri M. M. , Sharah H. S.

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tom 09

EN

Leaf beetles and fruitfly infestation greatly limits water melon (Citrullus lanatus) production throughout the tropics. The efficacy of aqueous plant extracts applied at 5 % w/v concentration of two botanicals (neems seed oil and garlic bulb) and 1.5 melt of one synthetic insecticide (karate 2.5 EC) against their infestation were evaluated. The effects of these treatments including control on the number of the insects, number of leaves, vines, length of vines, number of fruits, fruit weight, fruit damaged and undamaged were assessed during 2012 and 2013 cropping seasons in Lawanti, Gombe state, Northern Guinea Savannah region of Nigeria. Result of the study showed that neem seed oil and garlic bulb treatments at 5 % w/v were effective against the leaf beetles and water melon fruitfly as the synthetic insecticide karate 2.5 EC in managing the water melon insect pests. Karate 2.5 EC significantly reduced the infestation of the insect pests of water melon and increased number of leaves, vines, length of vines, number of fruits, fruit weight and number of undamaged fruits/plot followed closely by neem seed oil (A. indica) and garlic bulb (A. sativum) extracts. Water melon a growth and fruit yields were appreciably improved in these treatment while untreated control water melon crops had more leafs beetles and fruitfly infestations, poor plant growth and lower fruit yields. Both botanicals can thus serve as alternatives to synthetic insecticides for managing water melon leaf beetles and fruitfly attack.

5

Comparative analysis of eight neotropical savanna ecosystems: production-decomposition indexes

84%

Breymeyer A. I.

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tom 49

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nr 4

6

The paleoecology of the Late Miocene mammals from the Optima Local Fauna of Oklahoma, USA

67%

Frederickson J. A. , Cohen J. E. , Engel M. H. , Hunt T. C. , Wilbert G. A. , Castaneda O. S. , Czaplewski N. J.

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tom 67

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nr 1

7

Yield evaluation of three sesame (Sesamum indicum L.) varieties intercropped with maize (Zea mays L.) in a Southern Guinea Savannah location, Nigeria

67%

Ijoyah M. O. , Iorlamen T. , Fanen F. T.

International Letters of Natural Sciences

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2014

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tom 18

EN

Field experiments were conducted from July to November during the 2012 and 2013 cropping seasons, at the Research Farm, University of Agriculture, Makurdi, Nigeria, to evaluate the yields of two newly introduced sesame varieties (Ex Sudan and SN 603) against the commonly grown variety “E-8” under intercropping with maize variety „Oba 98‟. The trial area consisted of a total of seven treatments, replicated three times in a randomized complete block design. The results showed that, though maize yield was not significantly (P ≤ 0.05) affected by intercropping with sesame varieties, however, intercropped yield of sesame variety „Ex Sudan‟ was significantly (P ≤ 0.05) greater by 26.8 % and 25.6 % respectively, in years 2012 and 2013, compared to that obtained from intercropped sesame variety „SN 603‟, and by 19.5 % and 20.9 % respectively, in years 2012 and 2013, compared to that produced from intercropped popular sesame variety „E-8‟. Intercropping maize variety „Oba 98‟ with sesame variety „Ex Sudan‟ gave the highest total intercrop yield, greatest biological efficiency with a relative yield total values of 0.87 and 0.91 respectively, in 2012 and 2013. The combination also recorded the highest land equivalent ratio (LER), highest land equivalent coefficient, highest area x time equivalent ratio (ATER), highest total monetary returns (N584,200 and N588,600 respectively, in years 2012 and 2013) and highest monetary equivalent ratio (MER). The implication of study showed that sesame variety „Ex Sudan‟ performed best and could therefore be recommended as a potential replacement for the popular variety „E-8‟ under intercropping with maize variety „Oba 98‟ in Makurdi, Nigeria.

8

Intercrop advantages of some improved sweet potato + soybean in Makurdi, Benue State, Nigeria

67%

Egbe M. O. , Osang P. O.

International Letters of Natural Sciences

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2015

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tom 39

EN

Field trials were conducted during 2011 and 2012 cropping seasons at the Teaching and Research Farm of the University of Agriculture Makurdi, Benue State located in Southern Guinea Savanna of Nigeria. The objective of the study was to evaluate the response of some improved sweet potato varieties planted at three densities to intercropping with soybean. The experiment was a 2x3x3 split-split plot laid out in a randomized complete block design with three replications. The main plot consisted of two cropping systems [sole cropping (sweet potato, soybean) and intercropping (sweet potato + soybean). The sub-plot consisted of three sweet potato varieties (CIP440037, NRSP/05/007C and CIP440141). The sub-sub-plot treatment comprised of three sweet potato planting densities (25,000 plants/ha, 33,000 plants/ha and 50,000 plants/ha). Intercropping severely depressed the yields of both sweet potato varieties and the soybean component, such that intercrop yields were rarely above 50% of sole crop yields, irrespective of the sweet potato variety used. The number and weight of the sweet potato component was not significantly affected at the planting density of 50,000 plants/ha. Indices used to measure intercrop advantage showed that intercropping these sweet potato varieties with soybean was biologically efficient and percentage land saved varied from 23.08 and 32.43. Soybean was more competitive than sweet potato at all densities tested.

9

Use of an ecohydrology model to predict the impact on the Serengeti ecosystem of deforestation, irrigation and the proposed Amala Weir Water Diversion Project in Kenya

67%

Gereta E. , Wolanski E. , Borner M. , Serneels S.

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tom 02

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nr 1-4

EN

The Mara River catchment is the dry weather refuge for more than one million migrating wildebeest and zebras of the Serengeti ecosystem. The river flow is affected by developments in Kenya, including deforestation and water diversion for irrigation and the proposed Ewaso Ng’iro (South) Hydropower Project. An ecohydrology model was used to predict the likely impact of these developments on the Serengeti ecosystem. The model was forced by observed monthly rainfall in the period 1900-2000 and calibrated against observations of the number of wildebeest and lions also in the period 1960-1999. The projects are predicted to have little effect on the number of migrating wildebeest in the Serengeti until a drought occurs; historically a drought occurs about every seven years. At that time 20 to 80% of the migrating wildebeest may die, according to the severity and duration of the drought. With a 50% die-off, it may take twenty years for the population to recover; with an 80% die-off there may be no population recovery. In practice the economic benefits would go to Kenya while Tanzania would suffer the economic costs, eg the negative impact on the tourism industry. To ensure sustainable development for both Kenya and Tanzania, a transboundary Mara River management plan needs to be implemented and be compatible with ecohydrology principles for the sustainable use of aquatic resources.