scholarly journals Hippopotamus are distinct from domestic livestock in their resource subsidies to and effects on aquatic ecosystems

2020 ◽  
Vol 287 (1926) ◽  
pp. 20193000
Author(s):  
Frank O. Masese ◽  
Mary J. Kiplagat ◽  
Clara Romero González-Quijano ◽  
Amanda L. Subalusky ◽  
Christopher L. Dutton ◽  
...  
Keyword(s):  
Aquatic Ecosystems ◽  
Major Ions ◽  
Gross Primary Production ◽  
Cattle Dung ◽  
Resource Subsidies ◽  
Large Herbivores ◽  
Ecosystem Effects ◽  
Animal Dung ◽  
Large Numbers ◽  
Domestic Livestock

In many regions of the world, populations of large wildlife have been displaced by livestock, and this may change the functioning of aquatic ecosystems owing to significant differences in the quantity and quality of their dung. We developed a model for estimating loading rates of organic matter (dung) by cattle for comparison with estimated rates for hippopotamus in the Mara River, Kenya. We then conducted a replicated mesocosm experiment to measure ecosystem effects of nutrient and carbon inputs associated with dung from livestock (cattle) versus large wildlife (hippopotamus). Our loading model shows that per capita dung input by cattle is lower than for hippos, but total dung inputs by cattle constitute a significant portion of loading from large herbivores owing to the large numbers of cattle on the landscape. Cattle dung transfers higher amounts of limiting nutrients, major ions and dissolved organic carbon to aquatic ecosystems relative to hippo dung, and gross primary production and microbial biomass were higher in cattle dung treatments than in hippo dung treatments. Our results demonstrate that different forms of animal dung may influence aquatic ecosystems in fundamentally different ways when introduced into aquatic ecosystems as a terrestrially derived resource subsidy.

scholarly journals Distributions of Invasive Arthropods across Heterogeneous Urban Landscapes in Southern California: Aridity as a Key Component of Ecological Resistance

Insects ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 29 ◽  
Author(s):  
Weston Staubus ◽  
Savanah Bird ◽  
Savannah Meadors ◽  
Wallace Meyer
Keyword(s):  
Native Species ◽  
Southern California ◽  
Propagule Pressure ◽  
Urban Systems ◽  
Urban Landscapes ◽  
Resource Subsidies ◽  
Ecological Resistance ◽  
Large Numbers ◽  
Sage Scrub ◽  
Grassland Habitats

Urban systems often support large numbers of non-native species, but due to the heterogeneity of urban landscapes, species are not evenly distributed. Understanding the drivers of ecological resistance in urban landscapes may help to identify habitats that are most resistant to invasion, and inform efforts to model and conserve native biodiversity. We used pitfall traps to survey non-native ground-dwelling arthropods in three adjacent, low-elevation habitat types in southern California: California sage scrub, non-native grassland, and suburban development. We found that non-native species were fewer and less widely distributed in the sage scrub and grassland habitats. Due to the proximity of our sites, differences in propagule pressure is an unlikely explanation. Instead, we suggest that the absence of water subsidies in the sage scrub and grassland habitats increases those habitats’ resistance to arthropod invasions. Comparisons to studies conducted at fragments closer to the coast provide further support for the relationship between aridity and invasibility in southern California. Our findings highlight that inland fragments are important for conserving native arthropod diversity, that models of non-native species distributions in arid and semi-arid urban systems should include aridity measures, and that reducing resource subsidies across the region is critical to mitigating spread of non-natives.

Mechanized extraction of arthropods from cattle dung

1987 ◽  
Vol 77 (2) ◽  
pp. 239-246 ◽  
Author(s):  
R. W. Sutherst ◽  
A. Macqueen ◽  
B. M. Kelley ◽  
D. A. Stegeman ◽  
K. G. Asher ◽  
...  
Keyword(s):  
Large Scale ◽  
Motor Drives ◽  
Cattle Dung ◽  
Community Studies ◽  
Electric Motor Drives ◽  
Fine Mesh ◽  
Large Numbers ◽  
Arthropod Fauna ◽  
Eggs And Larvae ◽  
Dung Sample

AbstractEcological, population and community studies of arthropod fauna inhabiting dung require large-scale quantitative data to produce statistically adequate results. A mechanized extraction technique is described which recovers fauna accurately and rapidly from large numbers of cattle dung pads. The equipment comprises a motor-driven paddle which agitates the dung sample in a bucket with fine mesh panels inlaid into its walls and through which is passed a continuous flow of water. An electric motor drives five such units simultaneously. Most dipteran puparia and adult arthropods float on water and are recovered following the washing. Puparia are recovered manually, while mites and adult beetles are extracted from the floating debris with heat in modified Berlese-Tullgren funnels. The wash bucket and its drained contents are then immersed in a flotation vat through which a sodium carbonate solution is recirculated. Insect eggs and larvae are floated off into sieves and rinsed before preservation. The resulting samples are fixed and preserved in 70% ethanol for later identification and counting. The procedure recovered 70–90% of most types and stages of dung fauna. Up to 25 complete dung pads can be processed per day with a team of three people.

Salinisation and prospects for biodiversity in rivers and wetlands of south-west Western Australia

2003 ◽  
Vol 51 (6) ◽  
pp. 673 ◽  
Author(s):  
S. A. Halse ◽  
J. K. Ruprecht ◽  
A. M. Pinder
Keyword(s):  
Western Australia ◽  
Aquatic Ecosystems ◽  
Saline Water ◽  
Biological Communities ◽  
Invertebrate Species ◽  
South West ◽  
Large Numbers ◽  
High Concentrations ◽  
Water Volumes ◽  
Western Australian

Saline water was common in south-west Western Australian aquatic systems prior to land-clearing because most streams and wetlands were ephemeral and evapo-concentrated as they dried, and there were high concentrations of stored salt in groundwater and soil profiles. Nevertheless, a 1998 review of salinity trends in rivers of south-west Western Australia showed that 20-fold increases in salinity concentrations had occurred since clearing in the medium-rainfall zone (300–700 mm). More recent data confirm these trends and show that elevated salinities have already caused substantial changes to the biological communities of aquatic ecosystems. Further substantial changes will occur, despite the flora and fauna of the south-west being comparatively well adapted to the presence of salinity in the landscape. Up to one-third of wetland and river invertebrate species, large numbers of plants and a substantial proportion of the waterbird fauna will disappear from the wheatbelt, a region that has high biodiversity value and endemism. Increased salinities are not the only threat associated with salinisation: increased water volumes, longer periods of inundation and more widespread acidity are also likely to be detrimental to the biota.

scholarly journals Nitrogen fluxes in Western streams

2017 ◽  
Vol 40 ◽  
pp. 61-68
Author(s):  
Hilary L. Madinger ◽  
Robert O. Hall Jr.
Keyword(s):  
Nitrogen Fixation ◽  
Primary Production ◽  
Aquatic Ecosystems ◽  
Additional Data ◽  
Gross Primary Production ◽  
Dissolved Gas ◽  
Dissolved Nitrogen ◽  
Relationship Types ◽  
Stream Nitrate ◽  
The Relationship

Nitrogen pollution to streams is altering the nitrogen cycling in unknown ways, causing challenges for predicting nitrogen fixation fluxes within aquatic ecosystems. Increasing nitrate pollution decreases the amount of nitrogen fixation occurring in streams. However, the relationship between stream nitrate concentration and the rate of nitrogen fixation is unknown. We predict that lower nitrate streams will have the highest rates of nitrogen fixation. Additionally, there will be much more energy produced in streams with nitrogen fixation compared to the amount required to fix the nitrogen. We estimated whole-stream gross primary production and nitrogen fixation fluxes using the diel change in dissolved nitrogen and oxygen gases compared to the expected dissolved gas saturation. Our whole-stream method is preferable to chamber estimates to understand the relationship between energy requirements for nitrogen fixation and gross primary production, but additional data is needed to distinguish between relationship types and make our measurements generalizable.   Featured photo by Intermountain Forest Service, USDA Region 4 Photography on Flickr. https://flic.kr/p/jbTRUj

scholarly journals Hosts, seasonality and geographic distribution of the South African tortoise tick, Amblyomma marmoreum

2006 ◽  
Vol 73 (1) ◽  
Author(s):  
I.G. Horak ◽  
I.J. McKay ◽  
Heloise Heyne ◽  
A.M. Spickett
Keyword(s):  
South African ◽  
Adult Tick ◽  
Eastern Cape ◽  
Large Herbivores ◽  
Mpumalanga Province ◽  
The North ◽  
Numida Meleagris ◽  
Large Numbers ◽  
North Eastern ◽  
Northern Cape

The tortoise tick Amblyomma marmoreum was collected from large numbers of reptiles and other animals during the course of numerous surveys conducted in South Africa. A total of 1 229 ticks, of which 550 were adults, were recovered from 309 reptiles belonging to 13 species, with leopard tortoises, Geochelone pardalis being the most heavily infested. The 269 birds sampled harboured 4 901 larvae, 217 nymphs and no adult ticks, and the prevalence of infestation was greatest on hel meted guinea fowls, Numida meleagris. Only two larvae were recovered from 610 rodents, including 31 spring hares, Pedetes capensis, whereas 1 144 other small mammals yielded 1 835 immature ticks, of which 1 655 were collected from 623 scrub hares, Lepus saxatilis. The 213 carnivores examined harboured 2 459 ticks of which none were adult. A single adult tick and 6 684 larvae and 62 nymphs were recovered from 656 large herbivores, and a total of 4 081 immature ticks and three adults were collected from 1 543 domestic animals and 194 humans. Adult male and female A. marmoreum were most numerous on reptiles during January and February, and larvae during March. The largest numbers of larvae were present on domestic cattle and helmeted guineafowls in the Eastern Cape Province during March or April respectively, whereas larvae were most numerous on helmeted guineafowls, scrub hares and the vegetation in north-eastern Mpumalanga Province during May. In both provinces nymphs were most numerous between October and December. Amblyomma marmoreum appears to be most prevalent in the western regions of the Western and Eastern Cape and Free State provinces, and the north-eastern regions of the Northern Cape, KwaZulu- Natal, Mpumulanga and Limpopo provinces.

Potential risks of trophic impacts by escaped transgenic salmon in marine environments

2014 ◽  
Vol 42 (2) ◽  
pp. 152-161 ◽  
Author(s):  
LINGBO LI ◽  
TONY J. PITCHER ◽  
ROBERT H. DEVLIN
Keyword(s):  
Genetically Modified Organisms ◽  
Coho Salmon ◽  
Trophic Levels ◽  
Indigenous Species ◽  
Ecosystem Effects ◽  
Large Numbers ◽  
Complementary Approach ◽  
Potential Risks ◽  
Non Indigenous Species

SUMMARYThere is significant concern about potential ecological effects of introduced organisms, including non-indigenous species and those created by genetic modification. This paper presents an Ecopath with Ecosim modelling approach, designed to examine long-term trophic effects of growth hormone (GH) transgenic coho salmon should they ever escape to a coastal salmonid ecosystem, namely the Strait of Georgia in British Columbia (Canada). The model showed that the effects of introduced GH transgenic coho salmon varied with their biomass, diet, structure of the invaded ecosystem, and environmental conditions. Occasional escapes of non-reproductive salmon did not have a significant impact on the example ecosystem. However, effects of GH coho salmon varied with their diet when large numbers of these fish were present in the simulated ecosystem (for example, when they constituted 20% of total current aquaculture production in the area). Further, climate-driven changes in the biomass of low trophic levels (bottom-up effects) could have a greater impact on the ecosystem than the introduction of large numbers of GH coho salmon. A new version of Ecopath with Ecosim's Monte Carlo approach showed that the model predictions were robust to GH coho salmon's Ecopath parameters, but more sensitive to vulnerabilities of prey to GH coho salmon. Modelling ecosystem effects of genetically modified organisms provides a complementary approach for risk assessments when data from nature are not readily obtainable.

scholarly journals Collapse of the world’s largest herbivores

2015 ◽  
Vol 1 (4) ◽  
pp. e1400103 ◽  
Author(s):  
William J. Ripple ◽  
Thomas M. Newsome ◽  
Christopher Wolf ◽  
Rodolfo Dirzo ◽  
Kristoffer T. Everatt ◽  
...  
Keyword(s):  
Fire Regimes ◽  
Large Carnivores ◽  
Population Declines ◽  
Resource Depression ◽  
Ecological Processes ◽  
Large Herbivore ◽  
Large Herbivores ◽  
Cascading Effects ◽  
Ecosystem Effects ◽  
Herbivore Species

Large wild herbivores are crucial to ecosystems and human societies. We highlight the 74 largest terrestrial herbivore species on Earth (body mass ≥100 kg), the threats they face, their important and often overlooked ecosystem effects, and the conservation efforts needed to save them and their predators from extinction. Large herbivores are generally facing dramatic population declines and range contractions, such that ~60% are threatened with extinction. Nearly all threatened species are in developing countries, where major threats include hunting, land-use change, and resource depression by livestock. Loss of large herbivores can have cascading effects on other species including large carnivores, scavengers, mesoherbivores, small mammals, and ecological processes involving vegetation, hydrology, nutrient cycling, and fire regimes. The rate of large herbivore decline suggests that ever-larger swaths of the world will soon lack many of the vital ecological services these animals provide, resulting in enormous ecological and social costs.

scholarly journals Modification and Performance Evaluation of a Floating Drum Biogas Digester

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
F. Uthman
Keyword(s):  
Large Scale ◽  
Constant Pressure ◽  
Industrial Wastes ◽  
Cattle Dung ◽  
Scale Production ◽  
Inlet Pipe ◽  
Animal Dung ◽  
Large Scale Production ◽  
Accumulated Temperature ◽  
And Performance

Biogas is a renewable source of energy that is obtained from the anaerobic digestion of agricultural residues, animal dung, energy crops, domestic wastes and industrial wastes. These categories of waste that produce biogas are promising sources of energy and the biotechnology process of biofuel is environmentally friendly. This study aimed at modifying, fabricating and evaluating a floating drum digester. The modified floating drum digester consists of the digester tank, gas holder tank, feeding inlet pipe, gas collector outlet, slurry outlet, thermometer and hose. The gas holder tank was inserted into the digester tank while the biogas is generated in the digester tank by pressure. The biogas was produced from the mixture of cattle dung 30 % and 50 % plant wastes. Hence, the organic waste mixed with water in the ratio of 1: 2 for the digestion process. The digestion temperature was recorded daily for a period of 21 days at constant pressure of 1.32 KN/m2 throughout the experiment. The result revealed that the minimum and maximum average temperatures are 25 to 33 oC. This shows that the ambient temperature affects the temperature in the digester and the amount of gas produced is a function of the accumulated temperature in the digester. It was observed that the biogas generated increase as temperature rise. The modified floating drum digester is affordable and it is recommended for small- and large-scale production.

Cattle removal in arid Australia benefits kangaroos in high quality habitat but does not affect camels

2016 ◽  
Vol 38 (1) ◽  
pp. 73 ◽  
Author(s):  
Anke S. K. Frank ◽  
Glenda M. Wardle ◽  
Aaron C. Greenville ◽  
Chris R. Dickman
Keyword(s):  
Management Tool ◽  
Cattle Dung ◽  
Habitat Types ◽  
High Quality ◽  
Large Herbivores ◽  
Clear Preference ◽  
High Rainfall ◽  
Grazing Impacts ◽  
Macropus Rufus ◽  
Arid Rangelands

Removing cattle as a management tool to conserve biodiversity may not necessarily alter grazing impacts on vegetation if other introduced or native herbivores move in and replace the cattle after removal. This study investigated whether there was a difference in the abundance of native red kangaroos (Osphranter (Macropus) rufus) and introduced feral camels (Camelus dromedarius) on arid rangelands where cattle had been recently removed compared with where cattle remained. Activity was measured by clearing and weighing dung, and by counting animal sightings. Kangaroos were encountered more frequently in high quality habitat (gidgee woodland) where cattle had been recently removed. However, kangaroo dung in newly cattle-free areas comprised only ~1.5% of the weight of cattle dung in this habitat where cattle still grazed, indicating no grazing compensation by the native herbivore. Camels showed no clear preference for particular habitat types but used dune tops usually avoided by kangaroos and cattle. There was no indication of camels using habitats differently in areas where cattle were removed. Camel dung collected across all habitats comprised less than a tenth the weight of cattle dung, but almost five times as much as kangaroo dung. As cattle removal had occurred relatively recently, further monitoring is needed to determine its impact over longer periods, especially through low and high rainfall cycles. Methods to improve the monitoring of large herbivores in the presence and absence of livestock and to assess whether anticipated conservation goals are achieved are discussed.

scholarly journals Community Ecology and Conservation of Bear-Salmon Ecosystems

2020 ◽  
Vol 8 ◽  
Author(s):  
Taal Levi ◽  
Grant V. Hilderbrand ◽  
Morgan D. Hocking ◽  
Thomas P. Quinn ◽  
Kevin S. White ◽  
...  
Keyword(s):  
Original Data ◽  
Resource Provisioning ◽  
Black Bears ◽  
Apex Predators ◽  
Resource Subsidies ◽  
Resource Base ◽  
Ecosystem Effects ◽  
Calf Survival ◽  
In The Wild ◽  
Complex Ecosystem

Apex predators play keystone roles in ecosystems through top-down control, but the effects of apex omnivores on ecosystems could be more varied because changes in the resource base alter their densities and reverberate through ecosystems in complex ways. In coastal temperate ecosystems throughout much of the Northern Hemisphere, anadromous salmon once supported abundant bear populations, but both taxa have declined or been extirpated from large parts of their former ranges with limited research on the consequences of diminished or absent interactions among species. Here we review the biogeography of bear-salmon interactions and the role of salmon-subsidized bears in (1) resource provisioning to plants and scavengers through the distribution of salmon carcasses, (2) competition among bears and other large carnivores, (3) predation of ungulate neonates, (4) seed dispersal, and (5) resource subsidies to rodents with seed-filled scats. In addition to our review of the literature, we present original data to demonstrate two community-level patterns that are currently unexplained. First, deer densities appear to be consistently higher on islands with abundant brown bears than adjacent islands with black bears and wolves, and moose calf survival is higher at low bear densities (<∼25 bears per 100 km2) but is constant across the vast majority of bear densities found in the wild (i.e., ∼>25 bears per 100 km2). Our review and empirical data highlight key knowledge gaps and research opportunities to understand the complex ecosystem effects related to bear-salmon interactions.

Sign in / Sign up

Export Citation Format

Share Document