Large herbivore responses to surface water and land use in an East African savanna: implications for conservation and human-wildlife conflicts

2014 ◽  
Vol 23 (3) ◽  
pp. 573-596 ◽  
Author(s):  
Joseph O. Ogutu ◽  
Robin S. Reid ◽  
Hans-Peter Piepho ◽  
Nicholas T. Hobbs ◽  
Michael E. Rainy ◽  
...  
Keyword(s):  
Land Use ◽  
Surface Water ◽  
East African ◽  
African Savanna ◽  
Large Herbivore ◽  
Herbivore Responses

Anthropogenic stressors influence small mammal communities in tropical East African savanna at multiple spatial scales

2015 ◽  
Vol 42 (2) ◽  
pp. 119 ◽  
Author(s):  
Andrea E. Byrom ◽  
Ally J. K. Nkwabi ◽  
Kristine Metzger ◽  
Simon A. R. Mduma ◽  
Guy J. Forrester ◽  
...  
Keyword(s):  
Land Use ◽  
Small Mammal ◽  
Habitat Type ◽  
Local Scale ◽  
Natural Ecosystems ◽  
East African ◽  
African Savanna ◽  
Serengeti Ecosystem ◽  
Anthropogenic Stressors ◽  
Small Mammal Community

Context Protection of natural ecosystems undoubtedly safeguards ecological communities, with positive benefits for ecosystem processes and function. However, ecosystems are under threat from anthropogenic stressors that reduce the resilience both of component species and the system as a whole. Aims To determine how anthropogenic stressors (land use and climate change) could impact the diversity and resilience of a small mammal community in the greater Serengeti ecosystem, an East African savanna comprising Serengeti National Park (SNP) and adjacent agro-ecosystems, at local (SNP) and Africa-wide geographic scales. Methods We recorded small mammal species in 10 habitats in the greater Serengeti ecosystem, including the agro-ecosystem, over 48 years (1962–2010). We calculated richness and diversity for each habitat type, and used an index of similarity to quantify differences in the community among habitats. Species accumulation curves were also generated for each habitat type. Key results We recorded 40 species of small mammals in the greater Serengeti ecosystem. At the local scale, restricted habitat types in SNP (each <1% of the total area) made a disproportionately large contribution to diversity. Agro-ecosystems had lower richness and were less likely to contain specialist species. At regional and Africa-wide scales, local endemics were less likely to be recorded in the agro-ecosystem (57% species loss) compared with those with regional (33% loss) or Africa-wide (31%) geographic distributions. Conclusions At the local scale, the variety of habitats in SNP contributed to overall diversity. However, the ability to maintain this diversity in the adjacent agro-ecosystem was compromised for localised endemics compared with species with Africa-wide ranges. Land use intensification adjacent to SNP and projected changes in rainfall patterns for East Africa under global climate scenarios may compromise the future resilience of the small mammal community in this tropical savanna ecosystem. Implications The loss of rare or specialised species from protected areas and human-modified ecosystems could be mitigated by: (1) increasing habitat complexity and maintaining specialist habitats in the agro-ecosystem; and (2) creating buffers at the boundary of protected natural ecosystems that accommodate regime shifts in response to climatic change. These measures would increase the resilience of this coupled human–natural savanna ecosystem.

Phthalate esters in surface water of Songhua River watershed associated with land use types, Northeast China

2017 ◽  
Vol 25 (8) ◽  
pp. 7688-7698 ◽  
Author(s):  
Zhidan Wen ◽  
Xiaoli Huang ◽  
Dawen Gao ◽  
Ge Liu ◽  
Chong Fang ◽  
...  
Keyword(s):  
Land Use ◽  
Surface Water ◽  
Northeast China ◽  
Phthalate Esters ◽  
Songhua River ◽  
River Watershed ◽  
Land Use Types

Density dependence and the spread of invasive big-headed ants (Pheidole megacephala) in an East African savanna

Oecologia ◽  
2021 ◽  
Author(s):  
Alejandro G. Pietrek ◽  
Jacob R. Goheen ◽  
Corinna Riginos ◽  
Nelly J. Maiyo ◽  
Todd M. Palmer
Keyword(s):  
Density Dependence ◽  
East African ◽  
African Savanna ◽  
Pheidole Megacephala

Taking the pulse of Mother Ganga - Revealing the visible and invisible water pollution crisis along the Ganges River

2021 ◽  
Author(s):  
Stefan Krause ◽  
Keyword(s):  
Water Pollution ◽  
Water Quality ◽  
Land Use ◽  
Surface Water ◽  
River Network ◽  
Ganges River ◽  
Sediment Samples ◽  
Water And Sediment ◽  
The Ganges ◽  
Water And Sediment Samples

&lt;p&gt;It is probably hard to overestimate the significance of the River Ganges for its spiritual, cultural and religious importance. As the worlds&amp;#8217; most populated river basin and a major water resource for the 400 million people inhabiting its catchment, the Ganges represents one of the most complex and stressed river systems globally. This makes the understanding and management of its water quality an act of humanitarian and geopolitical relevance. Water quality along the Ganges is critically impacted by multiple stressors, including agricultural, industrial and domestic pollution inputs, a lack and failure of water and sanitation infrastructure, increasing water demands in areas of intense population growth and migration, as well as the severe implications of land use and climate change. Some aspects of water pollution are readily visualised as the river network evolves, whilst others contribute to an invisible water crisis (Worldbank, 2019) that affects the life and health of hundreds of millions of people.&lt;/p&gt;&lt;p&gt;We report the findings of a large collaborative study to monitor the evolution of water pollution along the 2500 km length of the Ganges river and its major tributaries that was carried out over a six-week period in Nov/Dec 2019 by three teams of more than 30 international researchers from 10 institutions. Surface water and sediment were sampled from more than 80 locations along the river and analysed for organic contaminants, nutrients, metals, pathogen indicators, microbial activity and diversity as well as microplastics, integrating in-situ fluorescence and UV absorbance optical sensor technologies with laboratory sample preparation and analyses. Water and sediment samples were analysed to identify the co-existence of pollution hotspots, quantify their spatial footprint and identify potential source areas, dilution, connectivity and thus, derive understanding of the interactions between proximal and distal of sources solute and particulate pollutants.&lt;/p&gt;&lt;p&gt;Our results reveal the co-existence of distinct pollution hotspots for several contaminants that can be linked to population density and land use in the proximity of sampling sites as well as the contributing catchment area. While some pollution hotspots were characterised by increased concentrations of most contaminant groups, several hotspots of specific pollutants (e.g., microplastics) were identified that could be linked to specific cultural and religious activities. Interestingly, the downstream footprint of specific pollution hotspots from contamination sources along the main stem of the Ganges or through major tributaries varied between contaminants, with generally no significant downstream accumulation emerging in water pollution levels, bearing significant implications for the spatial reach and legacy of pollution hotspots. Furthermore, the comparison of the downstream evolution of multi-pollution profiles between surface water and sediment samples support interpretations of the role of in-stream fate and transport processes in comparison to patterns of pollution source zone activations across the channel. In reporting the development of this multi-dimensional pollution dataset, we intend to stimulate a discussion on the usefulness of large river network surveys to better understand the relative contributions, footprints and impacts of variable pollution sources and how this information can be used for integrated approaches in water resources and pollution management.&lt;/p&gt;

Large herbivores suppress liana infestation in an African savanna

2021 ◽  
Vol 118 (41) ◽  
pp. e2101676118
Author(s):  
Tyler C. Coverdale ◽  
Ryan D. O’Connell ◽  
Matthew C. Hutchinson ◽  
Amanda Savagian ◽  
Tyler R. Kartzinel ◽  
...  
Keyword(s):  
Stable State ◽  
Life Forms ◽  
Tree Canopy ◽  
Alternative Stable State ◽  
African Savanna ◽  
Large Herbivore ◽  
Large Herbivores ◽  
Woody Vines ◽  
Plant Life Forms ◽  
Canopy Area

African savannas are the last stronghold of diverse large-mammal communities, and a major focus of savanna ecology is to understand how these animals affect the relative abundance of trees and grasses. However, savannas support diverse plant life-forms, and human-induced changes in large-herbivore assemblages—declining wildlife populations and their displacement by livestock—may cause unexpected shifts in plant community composition. We investigated how herbivory affects the prevalence of lianas (woody vines) and their impact on trees in an East African savanna. Although scarce (<2% of tree canopy area) and defended by toxic latex, the dominant liana, Cynanchum viminale (Apocynaceae), was eaten by 15 wild large-herbivore species and was consumed in bulk by native browsers during experimental cafeteria trials. In contrast, domesticated ungulates rarely ate lianas. When we experimentally excluded all large herbivores for periods of 8 to 17 y (simulating extirpation), liana abundance increased dramatically, with up to 75% of trees infested. Piecewise exclusion of different-sized herbivores revealed functional complementarity among size classes in suppressing lianas. Liana infestation reduced tree growth and reproduction, but herbivores quickly cleared lianas from trees after the removal of 18-y-old exclosure fences (simulating rewilding). A simple model of liana contagion showed that, without herbivores, the long-term equilibrium could be either endemic (liana–tree coexistence) or an all-liana alternative stable state. We conclude that ongoing declines of wild large-herbivore populations will disrupt the structure and functioning of many African savannas in ways that have received little attention and that may not be mitigated by replacing wildlife with livestock.

scholarly journals Waterborne Viruses and F-Specific Coliphages in Mixed-Use Watersheds: Microbial Associations, Host Specificities, and Affinities with Environmental/Land Use Factors

2016 ◽  
Vol 83 (3) ◽  
Author(s):  
Tineke H. Jones ◽  
Julie Brassard ◽  
Edward Topp ◽  
Graham Wilkes ◽  
David R. Lapen
Keyword(s):  
Land Use ◽  
Surface Water ◽  
Surface Waters ◽  
Water Samples ◽  
Land Development ◽  
Hepatitis E ◽  
Surface Water Flow ◽  
Mixed Use ◽  
Human Viruses ◽  
Waterborne Viruses

ABSTRACT From the years 2008 to 2014, a total of 1,155 water samples were collected (spring to fall) from 24 surface water sampling sites located in a mixed-used but predominantly agricultural (i.e., dairy livestock production) river basin in eastern Ontario, Canada. Water was analyzed for viable F-specific DNA (F-DNA) and F-specific RNA (F-RNA) (genogroup I [GI] to GIV) coliphage and a suite of molecularly detected viruses (norovirus [GI to GIV], torque teno virus [TTV], rotavirus, kobuvirus, adenovirus, astrovirus, hepatitis A, and hepatitis E). F-DNA and F-RNA coliphage were detected in 33 and 28% of the samples at maximum concentrations of 2,000 and 16,300 PFU · 100 ml−1, respectively. Animal TTV, human TTV, kobuvirus, astrovirus, and norovirus GIII were the most prevalent viruses, found in 23, 20, 13, 12, and 11% of samples, respectively. Viable F-DNA coliphage was found to be a modest positive indicator of molecularly detected TTV. F-RNA coliphage, unlike F-DNA coliphage, was a modest positive predictor of norovirus and rotavirus. There were, however, a number of significant negative associations among F-specific coliphage and viruses. F-DNA coliphage densities of >142 PFU · 100 ml−1 delineated conditions when ∼95% of water samples contained some type of virus. Kobuvirus was the virus most strongly related to detection of any other virus. Land use had some associations with virus/F-specific coliphage detection, but season and surface water flow were the variables that were most important for broadly delineating detection. Higher relative levels of detection of human viruses and human F-RNA coliphage were associated with higher relative degrees of upstream human land development in a catchment. IMPORTANCE This study is one of the first, to our knowledge, to evaluate relationships among F-specific coliphages and a large suite of enteric viruses in mixed-use but agriculturally dominated surface waters in Canada. This study suggested that relationships between viable F-specific coliphages and molecularly detected viruses do exist, but they are not always positive. Caution should be employed if viable F-specific coliphages are to be used as indicators of virus presence in surface waters. This study elucidates relative effects of agriculture, wildlife, and human activity on virus and F-specific coliphage detection. Seasonal and meteorological attributes play a strong role in the detection of most virus and F-specific coliphage targets.

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