Cold stratification complements cold water in enhancing the germination of Juniperus procera seeds

Enhancing seed germination is a fundamental step for conservation of plant genetic resources but less is understood specifically for endangered native and endemic tree species in the tropics.We examined how cold stratification and application of different treatments impact the germination of Juniperus procera seeds. We collected seeds from nine different altitudes of Managesha forest, Oromia region, Ethiopia. The seeds were stored in gene bank at -10oC for four years for cold stratification as a dormancy breaking method. We employed three treatments: cold water, 70oC hot water and 100 ml of 1% H2O2 to setup germination experiment in completely randomized design with four replications (50 seeds each). The germinated seeds were counted every fifth day until no more germinated seeds were observed. We analyzed data using two-way ANOVA and the significant for mean difference among altitudinal gradients was computed with Tukey HSD tests. The germination percent from cold stratified and moistened in cold water was higher than either from control, soaking in 70oC hot water or applying 1% H2O2 solution. Moreover, the germination percent varied among the altitudinal gradients for all the three treatments. At some altitudes, the germination was higher or lower consistently throughout control and the three treatments. The variations in altitudinal gradient and the associated environmental factors have triggered the differences in germinability of J. procera seeds. Our overall results suggest that cold stratification can complement cold water to break the dormancy and enhance the germination of J. procera seeds

The antiviral properties of edible medicinal plants: potential remedies against coronaviruses

SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) is an unparalleled challenge for the international community. Subsequently, an extraordinary effort has been made to contain SARS-CoV-2. However, this has been largely limited to behavioral changes and vaccination. To make the containment strategies effective, behavioral changes and vaccination need to be complemented with alternative prevention methods and curative treatments. This work reports the antiviral properties of some of the commonly known edible medicinal plants that can be used as potential remedies to suppress coronaviruses. A growing body of evidence substantiates that edible medicinal plants with antiviral properties that have been proven effective against sibling coronaviruses likely contain the spread of SARS-CoV-2, and they may also suppress the fatality of COVID-19 (coronavirus disease 2019). The secondary metabolites found in herbal medicines do not cause pathogens to develop drug resistance, which is a common problem in conventional medicines. The use of edible medicinal plants is much safer and causes less panic, thereby avoiding the fear associated with the use of herbal medicines. Right dosages and mixtures of edible medicinal plants need to be rigorously investigated to circumvent unanticipated side effects and chronic health risks

Crop pests and predators exhibit inconsistent responses to surrounding landscape composition

The idea that noncrop habitat enhances pest control and represents a win–win opportunity to conserve biodiversity and bolster yields has emerged as an agroecological paradigm. However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous across studies and effects on pests are inconclusive. The observed heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and biocontrol are measured. Here, we use a pest-control database encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates, and crop damage as a function of landscape composition. Our results showed that although landscape composition explained significant variation within studies, pest and enemy abundances, predation rates, crop damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes with more noncrop habitat but overall showing no consistent trend. Thus, models that used landscape-composition variables to predict pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our work shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others. Future efforts to develop tools that inform farmers when habitat conservation truly represents a win–win would benefit from increased understanding of how landscape effects are modulated by local farm management and the biology of pests and their enemies

Pests and pest controlling organisms across tropical agroecological landscapes in relation to forest and tree-cover

A major challenge in agroecosystems is how to manage the systems so that it reduces crop pests and enhances natural pest control. This thesis investigates patterns of crop pests and top-down effects of birds and arthropod predators in relation to land-use composition across spatial scales. In paper (I) I examined the crop distribution and land-use types in relation to the crop raiding patterns in 15 transectsin sites close to and far from forests along with a questionnaire survey at household level. I found severe crop raiding close to forests, but it had no impact on crop composition growing between the two sites. In paper (II) I examined the effect of forest and tree cover, at local and landscape scales, on the abundance of arthropod predators by collecting specimens from 40 home gardens. My result showed higher abundance of arthropod predators when either the home garden or the surroundings had a high tree-cover, compared to when tree-cover at both scales was similarly either high or low. In paper (III) I investigated the effect of excluding birds and arthropod predators on leaf damage on rape seed in 26 home gardens. I found stronger top-down impacts from arthropod predators on crop pests in tree-poor gardens than in tree-rich gardens. There was no effect of birds. In paper (IV) I explored the effect of landscape complexity on bird and arthropod predation using plasticine caterpillars in 36 home gardens across landscapes. The rate of arthropod predation on caterpillars was higher in simple than in complex landscapes. The rate of bird predation did not vary between complex and simple landscapes. In simple landscapes, arthropod predation was higher than that of birds. The overall results suggest that simplified gardens/landscapes still have enough habitat heterogeneity to support arthropod predators for the significant top-down controlling effect on crop pests. However, I did not find clear effect of complexityon the top-down effect of birds.At the time of the doctoral defence the following papers were unpublished and had a status as follows: Paper 1: Manuscript; Paper 3: Manuscript; Paper 4: Manuscript</p

Crop pests and Natural Enemies in Agricultural Landscapes in Relation to Spatial Heterogeneity of Wild Trees and Forests

The conversion of natural habitat for human use such as, agricultural intensification and others cause the simplification of landscape and loss of biodiversity. The fragmentation of landscape may influence the ecological functions like trophic cascades or predator-prey-primary producer interactions either directly or indirectly. This paper presents the review of the major theories in population regulation, island biogeography, and general concepts in brief and some reports of research findings in trophic cascades, population dynamics of natural enemies in agricultural landscape in both temperate and tropical contexts. The result of the review indicated that the heterogeneity of agricultural landscape (e.g. from simple crop habitat to complex natural habitat) determines not only the cross-edge spillover but also affects the magnitude (abundance), direction of flow and diversity of natural enemies and crop pests. As a result, the efficiency of natural regulation of crop pests in top-down and bottom-up processes may vary accordingly.  Nevertheless, from the literature I have assessed, I would suggest that further empirical research is needed to get a comprehensive understanding concerning the relationship between natural pest regulation functions (top-down and bottom-up mechanisms) and crop pests in agroecosystem both at local and regional scales. This suggestion may be vital mainly in tropical regions context where the high biodiversity is declining rapidly on one hand and where little information is currently available on the other verge

Haulm Forage Value of Lentil Varieties in Central Ethiopia

The major livestock feed next to natural pasture in central highlands of Ethiopia is cereal crop residue; however, supplementation with additional nutritional entities is most often recommended.  The present study aims to examine the nutritive value of lentil haulm and how this value varies among the varieties and locations. For this, 80gms of haulm samples of Alemaya, Derash and local lentil varieties were collected with four replications from Bishoftu, Akaki, and Chefe-Donsa from on farm trial sites of Ethiopian institute of agricultural research. To test for the variation in haulm nutritional values among the varieties, two-way ANOVA was employed. The results showed that the interaction of variety and location had significant effect on crude protein (CP), neutral detergent fiber (NDF), metabolizable energy (ME) and in vitro organic matter digestibility (IVOMD) (P&lt;0.05). Here, CP content of lentil haulm was higher for a local variety when compared with the two commercial varieties. The haulm yield (4.38t/ha) and haulm dry matter yield (3.97 t DM/ha) were higher for Derash when compared with that of the local variety (P&lt;0.05). Overall, the present finding denoted that although in some cases the lentil haulm nutritional values and yields vary among varieties and were dependent on growing locations, it can be observed to have optimum feeding values to supplement livestock feed with the cereal crop residues in central Ethiopia

Woody species diversity and the carbon stock potentials of different land use types in agroecosystem of Jimma Ganati District, Western Ethiopia

We investigated the impact of land use types and topographical variables on the diversity of wood species and their carbon stocks in the studied agroecosystems. A generic allometric equation developed for woody plants in agricultural landscapes was used to estimate the carbon stock. We used a mixed-effects linear model using the lmer function in the lme4 package to test the effects of land use types and topographic variables on wood species diversity (Shannon diversity) and stem carbon stock potential. Our study result showed that there is significantly higher woody diversity (P 0.05) effect on aboveground and belowground carbon stock. The tree species' structural attributes such as height, DBH size, and basal area (BA) have a positive and statistically significant (P < 0.05) effect on carbon stock. The study also found that only a few high DBH class (old growth) tree individuals that are deliberately spared in cropland and grazing land matrix have a high carbon stock contribution. For example, seven species, Podocarpus falcatus, Ficus vasta, Prunus africana, Schefflera abyssinica, Ficus sur, Ekebergia capensis, and Apodytes dimidiate, contribute an estimated 70% of the estimated total carbon stock in the landscapes. These results indicate the need to protect such scattered old-trees in agricultural landscapes both for biodiversity conservation and carbon sequestration thereby integrating climate change adaptation and mitigation strategies into subsistence farming systems

Data from: Arthropod but not bird predation in Ethiopian homegardens is higher in tree-poor than in tree-rich landscapes

Bird and arthropod predation is often associated with natural pest control in agricultural landscapes, but the rates of predation may vary with the amount of tree cover or other environmental factors. We examined bird and arthropod predation in three tree-rich and three tree-poor landscapes across southwestern Ethiopia. Within each landscape we selected three tree-rich and three tree-poor homegardens in which we recorded the number of tree species and tree stems within 100 × 100 m surrounding the central house. To estimate predation rates, we attached plasticine caterpillars on leaves of two coffee and two avocado shrubs in each homegarden, and recorded the number of attacked caterpillars for 7–9 consecutive weeks. The overall mean daily predation rate was 1.45% for birds and 1.60% for arthropods. The rates of arthropod predation varied among landscapes and were higher in tree-poor landscapes. There was no such difference for birds. Within landscapes, predation rates from birds and arthropods did not vary between tree-rich and tree-poor homegardens in either tree-rich or tree-poor landscapes. The most surprising result was the lack of response by birds to tree cover at either spatial scale. Our results suggest that in tree-poor landscapes there are still enough non-crop habitats to support predatory arthropods and birds to deliver strong top-down effect on crop pests