scholarly journals How do African elephants utilize the landscape during wet season? A habitat connectivity analysis for Sioma Ngwezi landscape in Zambia

2021 ◽  
Author(s):  
Doubt Chibeya ◽  
Heather Wood ◽  
Sara Cousins ◽  
Kerryn Carter ◽  
Moses Amos Nyirenda ◽  
...  
2005 ◽  
Vol 126 (2) ◽  
pp. 247-259 ◽  
Author(s):  
Birgit Binzenhöfer ◽  
Boris Schröder ◽  
Barbara Strauss ◽  
Robert Biedermann ◽  
Josef Settele

Koedoe ◽  
2015 ◽  
Vol 57 (1) ◽  
Author(s):  
Robin M. Cook ◽  
Michelle D. Henley ◽  
Francesca Parrini

The presence of humans and African elephants (Loxodonta africana) in the Great Limpopo Transfrontier Park can create situations of potential human–elephant conflict. Such conflict will likely be exacerbated as elephant and human populations increase, unless mitigation measures are put in place. In this study we analysed the movement patterns of 13 collared adult African elephants from the northern Kruger National Park over a period of eight years (2006–2014). We compared the occurrence and displacement rates of elephant bulls and cows around villages in the Limpopo National Park and northern border of the Kruger National Park across seasons and at different times of the day. Elephants occurred close to villages more often in the dry season than in the wet season, with bulls occurring more frequently around villages than cows. Both the bulls and the cows preferred to use areas close to villages from early evening to midnight, with the bulls moving closer to villages than the cows. These results suggest that elephants, especially the bulls, are moving through the studied villages in Mozambique and Zimbabwe at night and that these movements are most common during the drier months when resources are known to be scarce.Conservation implications: Elephants from the Kruger National Park are moving in close proximity to villages within the Great Limpopo Transfrontier Park. Resettlement of villages within and around the park should therefore be planned away from elephant seasonal routes to minimise conflict between humans and elephants.


2018 ◽  
Vol 2 (2) ◽  
pp. 63-70 ◽  
Author(s):  
R. Obour

Broussonetia papyrifera is an exotic tree widely grown for paper production. Due to its prolific regeneration it has invaded forestcanopy gaps and degraded farmlands and has now become an invasive species in Ghana. In enhancing its value for use the plantwas evaluated as potential forage for grazing animals vis-à-vis other two existing forage plants: Ficus exasperata and Leucaenaleucocephala.The study assessed the palatability and preference of Broussonetia papyrifera using sheep and goats for the wet anddry seasons.The species were assessed in indoor pen feeding trials using eight-unit (3×3 m) pens with the cafeteria method.The amount of forage offered was 100g (fresh material) in all instances for each species and for ten minutes. Adesign basedon 3×2×2 factorial in Randomized Complete Block Design (RCBD) was used to test the differences in palatability betweenthe three forage species.Results revealed that palatability was higher (P<0.05) in Leucaena leucocephala compared with Ficusexasperata and Broussonetia papyrifera for sheep and goats across seasons. The trend shown might be the result of the effectsof familiarity with the Leucaena leucocephala since animals tend to select plants that are familiar than newly introduced andunfamiliar plants. The study also revealed high level of condensed tannin (CT) in Broussonetia papyrifera which might haveinterfered with forage intake by the animals.There were no significant differences in palatability of Broussonetia papyrifera forgoat in both dry and wet season interactions and Ficus exasperata for goat in both dry and wet season interactions (P>0.05).Thestudy concluded that Broussonetia papyrifera could be a potential feed for both sheep and goats across seasons.The researchrecommended that livestock farmers should incorporate Broussonetia papyrifera feed into their programmes for both sheep andgoats and should be introduced to animals from infancy so that it may become a familiar feed for them.


2020 ◽  
Vol 15 ◽  
Author(s):  
Jujuan Zhuang ◽  
Shuang Dai ◽  
Lijun Zhang ◽  
Pan Gao ◽  
Yingmin Han ◽  
...  

Background: Breast cancer is a complex disease with high prevalence in women, the molecular mechanisms of which are still unclear at present. Most transcriptomic studies on breast cancer focus on differential expression of each gene between tumor and the adjacent normal tissues, while the other perturbations induced by breast cancer including the gene regulation variations, the changes of gene modules and the pathways, which might be critical to the diagnosis, treatment and prognosis of breast cancer are more or less ignored. Objective: We presented a complete process to study breast cancer from multiple perspectives, including differential expression analysis, constructing gene co-expression networks, modular differential connectivity analysis, differential gene connectivity analysis, gene function enrichment analysis key driver analysis. In addition, we prioritized the related anti-cancer drugs based on enrichment analysis between differential expression genes and drug perturbation signatures. Methods: The RNA expression profiles of 1109 breast cancer tissue and 113 non-tumor tissues were downloaded from The Cancer Genome Atlas (TCGA) database. Differential expression of RNAs was identified using the “DESeq2” bioconductor package in R, and gene co-expression networks was constructed using the weighted gene co-expression network analysis (WGCNA). To compare the module changes and gene co-expression variations between tumor and the adjacent normal tissues, modular differential connectivity (MDC) analysis and differential gene connectivity analysis (DGCA) were performed. Results: Top differential genes like MMP11 and COL10A1 were known to be associated with breast cancer. And we found 23 modules in the tumor network had significantly different co-expression patterns. The top differential modules were enriched in Goterms related to breast cancer like MHC protein complex, leukocyte activation, regulation of defense response and so on. In addition, key genes like UBE2T driving the top differential modules were significantly correlated with the patients’ survival. Finally, we predicted some potential breast cancer drugs, such as Eribulin, Taxane, Cisplatin and Oxaliplatin. Conclusion: As an indication, this framework might be useful in understanding the molecular pathogenesis of diseases like breast cancer and inferring useful drugs for personalized medication


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Melinda Boyers ◽  
Francesca Parrini ◽  
Norman Owen-Smith ◽  
Barend F. N. Erasmus ◽  
Robyn S. Hetem

AbstractSouthern Africa is expected to experience increased frequency and intensity of droughts through climate change, which will adversely affect mammalian herbivores. Using bio-loggers, we tested the expectation that wildebeest (Connochaetes taurinus), a grazer with high water-dependence, would be more sensitive to drought conditions than the arid-adapted gemsbok (Oryx gazella gazella). The study, conducted in the Kalahari, encompassed two hot-dry seasons with similar ambient temperatures but differing rainfall patterns during the preceding wet season. In the drier year both ungulates selected similar cooler microclimates, but wildebeest travelled larger distances than gemsbok, presumably in search of water. Body temperatures in both species reached lower daily minimums and higher daily maximums in the drier season but daily fluctuations were wider in wildebeest than in gemsbok. Lower daily minimum body temperatures displayed by wildebeest suggest that wildebeest were under greater nutritional stress than gemsbok. Moving large distances when water is scarce may have compromised the energy balance of the water dependent wildebeest, a trade-off likely to be exacerbated with future climate change.


2021 ◽  
Vol 13 (11) ◽  
pp. 2075
Author(s):  
J. David Ballester-Berman ◽  
Maria Rastoll-Gimenez

The present paper focuses on a sensitivity analysis of Sentinel-1 backscattering signatures from oil palm canopies cultivated in Gabon, Africa. We employed one Sentinel-1 image per year during the 2015–2021 period creating two separated time series for both the wet and dry seasons. The first images were almost simultaneously acquired to the initial growth stage of oil palm plants. The VH and VV backscattering signatures were analysed in terms of their corresponding statistics for each date and compared to the ones corresponding to tropical forests. The times series for the wet season showed that, in a time interval of 2–3 years after oil palm plantation, the VV/VH ratio in oil palm parcels increases above the one for forests. Backscattering and VV/VH ratio time series for the dry season exhibit similar patterns as for the wet season but with a more stable behaviour. The separability of oil palm and forest classes was also quantitatively addressed by means of the Jeffries–Matusita distance, which seems to point to the C-band VV/VH ratio as a potential candidate for discrimination between oil palms and natural forests, although further analysis must still be carried out. In addition, issues related to the effect of the number of samples in this particular scenario were also analysed. Overall, the outcomes presented here can contribute to the understanding of the radar signatures from this scenario and to potentially improve the accuracy of mapping techniques for this type of ecosystems by using remote sensing. Nevertheless, further research is still to be done as no classification method was performed due to the lack of the required geocoded reference map. In particular, a statistical assessment of the radar signatures should be carried out to statistically characterise the observed trends.


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