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Discussion in 'Wildlife & Nature Conservation' started by DesertRhino150, 8 Jul 2018.

  1. DesertRhino150

    DesertRhino150 Well-Known Member

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    Ecological research gives an invaluable insight into how sometimes very different species interact with each other. It would also, for the more adventurous zoo, be a fascinating subject to explore - keeping species with ecological partnerships in close association that could potentially show how these species interact. To that end, I have decided to create this thread, where research or other articles about ecology can be shared. I have included some initial articles and pieces of research that may be of interest:

    - Research has found that dingoes in New South Wales can affect the shape of sand dunes in the Strzelecki Desert and in turn influences how the wind flows over the landscape. The Dingo Fence has acted as a barrier to dingoes and on the side where they are absent, feral cats and foxes have flourished. In turn, native herbivores such as hopping mice have declined and vegetation cover has increased in their absence. This has stabilised the dunes and created taller dune peaks. On the side of the fence where dingoes remain, the dunes are generally flatter and not as tall.
    https://phys.org/news/2018-07-dingoes-sculpt-sand-dunes-australian.html

    - The dusky-throated antshrike is among several alarm-calling birds that have been discovered to be a keystone species in the Amazonian rainforest. By alerting other birds to the presence of predators such as hawks and falcons, the antshrikes allow other species to use the middle layer of the rainforest where the risk of predator attack is higher, because of the combination of abundant cover and open space for a raptor to manoeuvre. To test this, eight antshrikes were caught from mixed-species flocks in Peru and kept in an aviary for several days. The results were varied from flocks without antshrikes, with other mixed flock members moving into dense cover and others moving up into the canopy. Whatever the result, the mixed flock system broke down. Birds in control flocks, where the antshrike was released immediately after capture tended to stay out in the open.
    https://phys.org/news/2018-05-amazonian-lookout-birds-species-dangerous.html#nRlv

    - In Southeast Alaska, brown and black bears are abundant because of salmon, but supplement their diet with berries. Once the seed-filled scats are dropped in the landscape, several species including Northwestern deer mice and Northern red-backed voles visited the scats to collect seeds that the bear has defecated. A single bear scat may contain enough seeds to support the daily energy requirements of 91 deer mice and in some areas bears are potentially capable of indirectly subsidising the energy needs of 45-65% of the local deer mouse populations. In turn, the rodents sometimes scatter-hoard the seeds and allow those seeds that they do not find again to germinate.
    https://phys.org/news/2018-07-berry-gorging-disperse-seeds-scat-small.html

    - This study from December 2017 catalogues the ecological impacts of reptiles in tropical areas. This includes their role as gene transporters (pollinators, seed dispersers and sessile invertebrates), nutrient transfer (the huge quantities of unhatched reptile eggs left buried on beaches and their role as prey for larger predators), 'trophic actors' (reptiles as predators or scavengers that occur at much higher numbers and biomass than mammalian carnivores) and ecosystem engineers (from grazing, burrow-digging, the creation of waterholes and the construction of rotting vegetation mounds by nesting crocodilians). It also addressed the issue of lack of conservation interest in reptiles against birds or mammals and offers options on how to redress this bias.
    The Plight of Reptiles as Ecological Actors in the Tropics
     
    Last edited: 8 Jul 2018
  2. DesertRhino150

    DesertRhino150 Well-Known Member

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    Studies on how forest ecology shapes the transmission rates of Lyme disease have found that there was both a bottom-up control (the year following a high acorn crop, the numbers of the white-footed mouse and chipmunk, which are both very efficient at transmitting Lyme disease, increased) and a top-down control (sites with high predator diversity had lower infection prevalence in tick nymphs; bobcats, foxes and opossums were all associated with a reduction in tick infection). At sites dominated by coyotes, which exclude smaller carnivores, the infection prevalence in tick nymphs was higher.
    https://phys.org/news/2018-07-forest-ecology-lyme-disease-eastern.html

    Marine ecologists have found that on islands adjacent to coral reefs that are free of rats and rich in seabirds have fish that grow larger and faster for their age than rat-infested islands. The biomass of the entire fish community was about 50 percent higher around rat-free islands. Herbivorous fish that clean algae of the reef and break up dead coral so allowing the reef to grow particularly did well around bird-heavy islands. The findings suggest that eradicating rats from coral reef islands may be a fairly simple way to improve the health of the surrounding marine ecosystem.
    Coral reefs thrive next to rat-free islands, new study finds
     
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  3. DesertRhino150

    DesertRhino150 Well-Known Member

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    I have seen information about some interesting ecological science, one more recent piece of research and a couple of other research papers that are older but still very interesting:

    - Recently-published research from the Yellowstone National Park area has found that the so-called 'Landscape of Fear' (created where herbivores avoid risky areas where their natural predators are most active) is not a static 24-hour consequence of a predator's mere presence. Elk in the Yellowstone area actively used areas where they are at risk of wolves during the night, as wolves mainly hunt at dawn and dusk and are as inactive in the middle of the night as they are at midday. This study helps explain why previous studies have found no clear-cut effect of wolf predation risk on elk stress levels, body condition, pregnancy or herbivory. Any impacts on the elk and cascading effects on the plants that elk eat are more likely due to actual killing than fear.

    An article about the study is included here:
    https://phys.org/news/2018-06-yellowstone-landscape-scary.html

    The abstract of the paper is included below:
    https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1002/ecm.1313

    The two older papers are both about the ecological impacts of the Liberian mongoose (Liberiictis kuhni), a species about which I have not heard much about.

    - The first study found that Liberian mongooses (along with other terrestrial mammalian and avian insectivores) are important as both predators and nutrient cyclers. In exclosures experiments, seedling herbivory rates were 4.3 times higher than control sites outside the exclosures. Herbivorous invertebrates (primarily cockroaches and grasshoppers), spiders and earthworms were all more abundant inside exclosures but some smaller invertebrates (springtails, mites and fungus gnats) showed the opposite trend. Also more scarce in the exclosures was inorganic phosphorus, a limiting nutrient in tropical soils.

    The full paper (in PDF format) is included below:
    https://scholarship.rice.edu/bitstream/handle/1911/21692/Dunham_2008_Oikos.pdf?sequence=1

    - The second study looked at how the dominant tree species in Tai National Park (the same site as the former study) responded to the presence or absence of the Liberian mongoose, the most frequent ground-disturbing species at the study side. It is estimated that the mongoose turns over the entire forest floor leaf litter in the study area over a course of about eight months. Seeds exposed to the bioturbation of mongooses saw a 6.5-fold increase in small-scale horizontal movement and also increased the chances of the seeds being buried. Burial essentially eliminated the removal of seeds by seed predators. In simulated disturbances the germination of the Raphia palm (Raphia palma-pinus), the dominant tree species in the area, was enhanced by 17.5% on average over the course of about four months. The loss of these terrestrial insectivores could have underappreciated but important impacts on tropical plant communities.

    The full paper is included below:
    https://pdfs.semanticscholar.org/3ef7/e3c350c36675ed4db385914139d1c22674f6.pdf
     
  4. DesertRhino150

    DesertRhino150 Well-Known Member

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    I have found another couple of interesting pieces of research from the Tai Forest in Cote d'Ivoire (where the two pieces of research about the Liberian mongoose from the previous post was done) and I figured I would put them here. One is a recent piece of work and the other is considerably older.

    - The more recent research has found that sooty mangabeys, together with both white-breasted and Western crested guineafowl and squirrels (exact species not mentioned in either abstract or other articles) scavenge the remnants of nuts cracked by chimpanzees and red river hogs. The mangabeys in particular could access food that was otherwise too tough for them to open; they were more likely to visit nut-cracking sites after nut-cracking has occurred while the other species showed no such relation. The mangabeys also showed heightened vigilance when visiting chimpanzee nut-cracking sites, as chimpanzees are occasional predators of mangabeys. The scavenging of cracked nuts is a foraging behaviour that has not been recorded prior to this study.

    An article about this research is included below:
    https://phys.org/news/2018-07-monkeys-benefit-nut-cracking-abilities-chimpanzees.html

    Included here is the abstract of the research paper itself:
    https://onlinelibrary.wiley.com/doi/abs/10.1002/ajp.22895

    - The older piece of research is a thesis from 1994 and looks at niche separation in the seven duiker species of the Tai Forest.
    The study found that Maxwell’s duiker is the most common species in both mature and secondary forest that is diurnal; its diet was restricted to food items either 3cm or less in diameter or soft enough to be broken up before swallowing. The next largest species, the zebra duiker, is a diurnal species recorded only from mature forest where it was regularly seen in adult pairs. The black, bay and Ogilby’s duiker are all similar in size – the black duiker was the second most common species in secondary forests while Ogilby’s duiker was only seen in mature forest; both these species are diurnal. The bay duiker is the second most common species in mature forest but does also occur in secondary forest; it is nocturnal and has a thicker neck and wide jaws to ingest larger food items than the black or Ogilby’s duikers. The two largest species, the yellow-backed and Jentink’s duiker are both active by both day and night. The yellow-backed duiker occurred only in secondary forest at the research site while the Jentink’s duiker only lives in mature forest and the areas around natural granite outcrops or inselbergs – where Jentink’s duiker is absent, the yellow-backed duiker occurs in mature forest which suggests a degree of competition.
    The other herbivores of the area are primarily leaf-eating, so do not compete with the fruit-eating duikers for food – royal antelope and bushbuck occurred only in secondary vegetation where they were common, the only sightings of forest buffalo were also from secondary vegetation although they travel through mature forest to reach isolated clearings and inselbergs and the bongo was probably absent from secondary vegetation as a result of hunting rather than food availability. The water chevrotain is also a frugivore and may compete with duikers but it is restricted to the vegetation around waterways and was not seen in the study area.

    The results I have included here are from pages 189-194 of this rather impressive document (which in part used behavioural information gathered from captive animals at Monrovia Zoo) included below:
    https://pdfs.semanticscholar.org/c8a6/bb647b8d3c20f74c682bdd88ec3d112686f2.pdf
     
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  5. Swampy

    Swampy Well-Known Member

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    I remember referencing that duiker study in a university assignment last year. Definitely worth a read.
     
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  6. DesertRhino150

    DesertRhino150 Well-Known Member

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    I have been looking around and found some more pieces of ecological research - although some are several years old I still think they are of sufficient interest to warrant posting here.

    Anomalures
    The first piece of research from late last year, looks at the ecology of anomalures living in Central Gabon. By studying hollow trees (the sole roosting area for these animals), three species were identified, namely the Lord Derby's anomalure Anomalurus derbianus, dwarf anomalure Anomalurus pusillus and the long-eared flying mouse Idiurus macrotis. The former and latter species were especially researched - the former largely roosted either alone or in pairs while the latter nested communally in groups of up to forty individuals. Sometimes the two species shared a hollow tree, together with three different species of bats including free-tailed bats Tadarida sp.
    Seven observations of feeding in Lord Derby's anomalure was observed, which consisted of gnawing off the bark of trees (three tree species recorded) and licking up phloem sap. Flying mice were observed gnawing the bark of one of the tree species also used by Lord Derby's. Individuals of both these species were radio marked to find out how far they range over a night and how many different trees are used for sleeping.
    The paper does not that in ecological terms, anomalures are more similar to Australian gliding possums than to flying squirrels, with Lord Derby’s anomalure having a niche fairly similar to the greater glider and the flying mouse being more similar to the sugar glider.
    A footnote of interest that I also noticed in the paper – a sighting was made of one of the marked female Lord Derby’s anomalures and her young being forced to escape from a second exit hole in their sleeping tree by a Central African oyan Poiana richardsoni entering the tree from the upper hole.

    The paper for this study is included below:
    https://hal.archives-ouvertes.fr/hal-01320856/document

    Bat-eared foxes
    Several interactions between insectivorous birds and mammals has been recorded in South Africa, with previous studies finding feeding associations between ant-eating chats and both aardvarks and aardwolves, between clapper larks and aardvarks and between aardwolves and aardvarks. This series of observations made during an ecological study of South African canids found four different bird species following feeding bat-eared foxes. Of these, ant-eating chats were seen to associate with bat-eared foxes on fifteen occasions, double-banded coursers four times, crowned lapwings three times and Northern black korhaan on one occasion. On two occasions larks were also seen shadowing the foxes but low light conditions and distance prevented them from being identified to species. All of the birds followed the foxes at close distance, ranging from between 0.5-2m in the courser, lapwing and korhaan and between 0.5-3m in the ant-eating chat. All the birds took advantage of termites that the foxes had excavated and this may be important to the birds during winter, when the termites spend more time underground.

    The full PDF of this study is included below:
    https://www.researchgate.net/profil...uth_Africa/links/0deec524c6ce8821ac000000.pdf

    Crested porcupine burrows
    This study looked at how the burrows of Indian crested porcupines are used by other species, dependent upon the burrow's characteristics. Six species (three mammals and three reptiles) were found occupying the nine burrows selected for analysis. Of these the Bengal monitor lizard was not evaluated and both the crested porcupines themselves and an unidentified species of gecko did not show any significant correlation with any burrow characteristics. In contrast, the golden jackal showed a significant positive correlation with mean chamber height, the fulvus roundleaf bat showed a negative correlation with the number of branches and openings in a burrow and the Indian rock python showed a strong negative correlation with both mean chamber height and width. Previous research at this study site found striped hyaenas using porcupine burrows as breeding dens but they only occur rarely in the area and were not found in this particular study. The findings of this study indicate that Indian crested porcupines are major ecosystem engineers and a primary excavator constructing ecologically significant burrows.

    The full PDF of this paper is included below:
    https://www.researchgate.net/profil...of-Keoladeo-National-Park-Rajasthan-India.pdf

    Badgers and other carnivores
    Research has been done on how badgers and their setts attract other carnivores in Russia; in total eleven different species of carnivore visited badger setts across two sites, one in European Russia (home to European badgers) and one in the Russian Far East (home to Asian badgers). Across both sites, raccoon dogs and red foxes used the setts in order to breed. All the other visitors were coming to search for food, either the badgers themselves or the rodents also found around the sett. In European Russia the three visiting species were grey wolf, Eurasian lynx (both likely badger predators) and European pine marten (a rodent predator). In the Russian Far East site the visitors were Eurasian lynx, brown and Asiatic black bear, yellow-throated marten (all likely to be hunting the badgers themselves), leopard cat, sable and Siberian weasel (rodent predators).
    Very little actual interaction was recorded between the species, although badgers were seen to flee underground at the approach of a bear - indeed, 82% of the setts in the Russian Far East study site showed signs of excavation by bears; also on one occasion raccoon dogs were seen to remove dead badger cubs from a sett although whether they were killed or scavenged is obviously not known.

    The abstract for this paper is included below:
    CEEOL - Article Detail

    The full paper is available on PDF, but it insists on being opened on another browser so I cannot include link it from here.

    Small carnivore ecosystem services
    I also figured I would include this interesting work about the ecosystem services of small mammalian carnivores in South Africa. An assessment (with camera traps) of cropped land, grazing land and settlements in two rural villages found nine species of small carnivore, of which rodents make up a significant part of the diet of seven of those species including the striped polecat, honey badger, slender mongoose, African civet and large-spotted genet. The greatest diversity of carnivore occurred on the croplands; use of an area by wild carnivores was negatively influenced by relative abundance of domestic dogs and positively influenced by relative abundance of livestock.
    Interviews with village residents found that they failed to appreciate how these small carnivores may be important in controlling crop pests. Indeed, although some recognised that these animals do eat rodents, they still have negative perceptions of them and often kill them. At present rodents, which destroy 15% of all the crops growing in Africa, are controlled largely by poisons which are expensive and eventually result in resistance in rodents. The research recommends using community outreach to teach about the positive benefits small carnivores could bring; similar projects have changed attitudes of South African farmers to birds of prey such as barn owls as well as snakes.
    There are a lot of interesting things that could be said about ecosystem services provided by animals, even if it is not ecology per se.

    The abstract for this paper is included here:
    https://www.sciencedirect.com/science/article/pii/S2212041617301699

    An article written about this research is included here:
    https://phys.org/news/2018-03-foe-friendhow-carnivores-helpfarmers.html
     
    Last edited: 20 Aug 2018
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  7. Swampy

    Swampy Well-Known Member

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  8. birdsandbats

    birdsandbats Well-Known Member

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    Bonnethead Sharks are common in captivity. How has no one noticed this before in captive animals. How have those only meat-fed captive animals stayed healthy?
     
  9. Kakapo

    Kakapo Well-Known Member

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    Because seagrasses are not so common in captivity, and when used in aquariums, they're always put in smaller tanks, not in the oceanic tanks that holds the medium and large sharks.

    Particularly, the fact of a shark actually feeding on seagrass and that percentage on the diet (not just using them as digestive aid like a cat) is atonishing and very surprising to me.
     
  10. DesertRhino150

    DesertRhino150 Well-Known Member

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    Research has recently found that the red-backed salamander Plethodon cinereus has a pivotal role in the forest ecosystems of North America. In many northeastern forests they outnumber all the birds and mammals combined, with one 2002 study in Virginia recording a density of 3 salamanders per square metre - 1 square kilometre could harbour 3 million red-backed salamanders.

    The salamander is a predator of small invertebrates that graze on fungal communities including snails and termites. By recreating small controlled representations of the forest floor habitat in laboratory enclosures (referred to as 'mesocosms'), scientists have found that red-backed salamanders directly control a forest's fungal community. The salamander's feeding habits affect both the density and diversity of fungus - in terms of diversity the salamanders affect fungus everywhere in the forest, from deep underground to those that grow in the canopy far above the forest floor.

    This recent discovery makes the threat posed by Batrachochytrium salamandrivorans fungus especially dangerous to the wider ecosystem in North America.

    The actual research paper is included here:
    salamander's top down effect on fungal communities in a detritivore ecosystem

    An article summarising the study and its findings is included here:
    Essential ubiquity: How one tiny salamander species has a huge impact
     
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  11. DesertRhino150

    DesertRhino150 Well-Known Member

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    Just seen some recent research that has been carried out on the diet of desert lions of the Hoanib Floodplain along the Namibian coast. Feeding on marine species, a behaviour that disappeared in the 1980s when the lion population was eradicated, is now becoming more frequent with three young lionesses especially turning to coastal food sources.

    Between May 2017 and November 2018, the lion's diet consisted of sixty cormorants (both Cape and white-breasted), eighteen Cape fur seals, two greater flamingos and two red-billed teal along with four black-backed jackals, two Cape crested porcupines and a gemsbok. While some of the seals were scavenged, the lions hunted all the birds and many of the seals including adult females.

    The abstract to this research is included below; there are PDFs available of the research if you put its title into Google Scholar.

    Lions (<i>Panthera leo</i>) specialising on a marine diet in the Skeleton Coast Park, Namibia | Namibian Journal of Environment
     
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  12. KevinB

    KevinB Well-Known Member

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    Not entirely sure if this fits in here, but it does seem to do so to me and I wouldn't know where else to share it.

    The Atlantic puffin, Fratercula arctica, has been found to be amongst the birds that use ultraviolet features, in that case in courtship.

    For more information see this article by the Audubon Society:
    Puffins Amp Up Their Sex Appeal With Glowing Beaks

    Abstract of the original study (couldn't locate a full version though):
    https://www.tandfonline.com/doi/full/10.1080/00063657.2018.1563771
     
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  13. DesertRhino150

    DesertRhino150 Well-Known Member

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    A couple of recent pieces of research that I think are of interest:

    The first paper studies interactions between arthropods and small vertebrates in the Peruvian Amazon. Predation on vertebrates is recorded in wandering and fishing spiders, tarantulas, giant centipedes, giant water bugs and stingless bees (the latter recorded only preying on frog eggs). The prey taken by arthropods includes mostly frogs but also lizards, snakes and one record of a Pamphobeteus tarantula predating a white-bellied slender opossum, the first record of a spider preying on a marsupial. Also included in the research are three records of fly myiasis in frogs and also records of commensal relationships between Pamphobeteus tarantulas and the narrow-mouthed frog Chiasmocleis royi, which amiably share the same burrows.

    The paper, with many pictures showing the different interactions, is included below:
    http://amphibian-reptile-conservati...3_1_[General_Section]_65-77_e169_high_res.pdf

    The second piece of research concerns the reintroduction of the Tasmanian devil to mainland Australia. By studying coprolites and fossil bones, it has been found that these animals were capable of tolerating a much wider range of climatic and environmental conditions than they currently occupy and also shared the mainland landscape with native small-to-medium sized species over a long period of time.

    The abstract for this paper is included below:
    https://www.sciencedirect.com/science/article/abs/pii/S0006320718310280?via=ihub

    An article about the research is included below:
    https://phys.org/news/2019-02-tassie-devils-feral-cats-mainland.html
     
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  14. DesertRhino150

    DesertRhino150 Well-Known Member

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    I have seen a number of recent research papers about ecology that might be of interest, so I am including them here:

    - This review shows the importance of aquatic predators (both fresh and saltwater) towards ecosystem function and services. This includes their role in controlling food webs, nutrient cycling, ecosystem engineering, reducing disease transmission, mediating species invasions, climate mitigation, tourism, fisheries and bioinspiration.

    An article about the research is included below, with the full paper included below that:
    https://phys.org/news/2019-03-explores-impacts-marine-freshwater-predators.html
    https://www.sciencedirect.com/science/article/pii/S0169534719300205

    - Fiddler crabs have been found to be critical ecosystem engineers in mangrove ecosystems by cycling the nutrients found in the sediment. The sediment the crabs deposited attracted a range of bacteria that help with the turnover of organic matter; in doing so increasing nutrient availability in the sediment.

    As above, the article is included on top and the actual research paper below:
    https://phys.org/news/2019-03-fiddlers-mangrove-ecosystems.html
    Fiddler crab bioturbation determines consistent changes in bacterial communities across contrasting environmental conditions

    - Following research on the role of wildebeest carcasses in the Mara River, this project looked at how pre-decline animal populations in North America may have influenced river nutrients. While abundant resident animals like alligator snapping turtles, mussels and beavers all likely had relatively small contributions to total phosphorus levels in the water (all 1.0% or less), massive pulses of carcasses such as mass-drownings of bison and caribou may have provided up to half the phosphorus in their respective rivers. Such drownings would have been commonplace before the loss of most terrestrial megafauna in North America and would have played a strong role in nutrient cycling.

    The article and research paper are both included below:
    https://phys.org/news/2019-03-animal-carcasses-source-river-nutrients.html
    https://www.sciencedirect.com/science/article/pii/S2352249618300429

    - Actual evidence of herbivores occupying new habitats and altering ecosystems following the disappearance of apex predators in mammals has been difficult to obtain. Research in Mozambique's Gorongosa National Park has found that, following the disappearance of leopard, hyaena and hunting dog, forest-dwelling bushbuck have moved into open habitats, are consuming novel food and suppressing growth of a common food plant (the waterwort Bergia mossambicensis). Experimentally simulating predator risk through leopard call playbacks found that this affect is reversible. Since the study has been completed, a pack of African hunting dogs has been reintroduced to Gorongosa and observations indicate they are mostly preying on the open-country bushbucks.

    The article (which contains details about the released hunting dogs) and research paper are included below:
    https://phys.org/news/2019-03-ecologists-landscape-fearlessness-war-torn-savannah.html
    http://science.sciencemag.org/content/early/2019/03/06/science.aau3561.abstract
     
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  15. DesertRhino150

    DesertRhino150 Well-Known Member

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    I have found four pieces of interesting-looking ecological research all from fairly recently, pertaining to two species of mammals:

    Puma
    - A study of 18 puma-killed carcasses for beetles recorded a total of 24,293 beetles representing 215 species. Eight families of beetle were significantly more abundant at puma kill sites than at empty control sites. This research suggests that the puma is an ecosystem engineer for scavenger communities and also suggests that there may be consequences for invertebrate communities where apex predators exist at reduced numbers or have been eradicated. The abstract to the paper can be read below:
    Pumas as ecosystem engineers: ungulate carcasses support beetle assemblages in the Greater Yellowstone Ecosystem

    - The earliest study of the four I have included looks at how puma carrion provides for larger scavengers in its ecosystem. Studying in the Greater Yellowstone area, a total of 242 puma-killed carcasses were filmed with camera traps, recording species that either fed on the carcass or on invertebrates attracted to the carcass. The study recorded a total of 39 scavenger species, comprising 17 mammal and 22 bird species, the highest diversity ever recorded in such a study. Puma kills were visited more than remains left by either wolves or human hunters. Because they are subordinate predators pumas are disproportionately important in providing carrion; the researchers also identified six other medium-sized cats that hunt large prey and are subordinate to larger predators that may also be disproportionately important for carrion provision, namely the cheetah, Eurasian lynx, leopard, snow leopard and both species of clouded leopard. The research can be found below:
    https://www.sciencedirect.com/science/article/pii/S0006320717303920

    Hippopotamus
    - Some very recent research has found that hippopotamus in the Mara River are critical to the cycling of silicon in the savannah ecosystem. By eating silicon-rich grass and depositing it as dung in the water, hippos may transport 0.4 metric tonnes of silicon into the water, representing up to 75% of the total silicon flux. Declines in hippos and disruption of river systems could prevent this silicon reaching areas such as Lake Victoria, where it supports the growth of diatoms that form the base of the whole freshwater ecosystem. The research paper can be found below:
    Hippos (Hippopotamus amphibius): The animal silicon pump

    - Another recent study from Ruaha National Park in Tanzania has found that in the dry season dung deposition into high-density hippo pools reduces dissolved oxygen to the extent that fish are forced to the surface and become increasingly lethargic. This encourages fish predators; approximately seven times as many fish-eating birds were observed at high-density pools as at low-density pools and these high-density pools were also the only place where yellow baboons engaged in fishing behaviour, a novel activity not observed before. The paper can be found below:
    https://labs.eemb.ucsb.edu/mccauley..._McCauley-2018-African_Journal_of_Ecology.pdf
     
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  16. birdsandbats

    birdsandbats Well-Known Member

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    Wow, both of those are very interesting! These studies show that the ecosystem is much more intertwined than anyone thought, and make me wonder what other things like these are out there.
     
  17. Terry Thomas

    Terry Thomas Well-Known Member Premium Member

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    I have spent quite a lot of time, over many years, in the desert areas of Australia. Many times I have seen the dingo fence and observed dingo tracks on both sides. The fence does deter dingoes, but does not always stop them. I have never been convinced that the fence really does a lot of good in controlling dingoes. It certainly helps control several other species. Dingoes are very smart; they can climb a fence, go around, under, and sometimes through. Cattle grids at road intersections are not much of a barrier to them either. (These are only my own personal observations).
     
  18. DesertRhino150

    DesertRhino150 Well-Known Member

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    Found another couple of interesting pieces of ecological research I thought I would share here:

    - Horned passalus beetles (Odontotaenius disjunctus) in the eastern United States are naturally parasitized by a nematode worm (Chondronema passali) that does little harm to the beetle. This is because the beetle feeds more to compensate for the food lost to the parasites. Research comparing parasitized and non-parasitized beetles found that those with nematodes processed dead wood at a rate 15% greater than those without. The presence of parasites increases the efficiency of the beetles at breaking down wood and parasitized beetles provide a more effective ecosystem service.

    The research paper can be found below:
    https://royalsocietypublishing.org/doi/10.1098/rsbl.2018.0842

    - A study of 105 juvenile tiger sharks in the Gulf of Mexico found that 41 individuals (39%) had consumed land birds of 11 different species - 8 of them were passerine songbirds along with the white-winged dove, yellow-bellied sapsucker and American coot. No marine birds were found in the shark's stomachs. The majority of the birds were consumed during the autumn - it is thought most likely that the sharks are scavenging the birds after they are forced down onto the water and drown during extreme weather events while migrating across the Gulf.

    The paper can be found below:
    https://esajournals.onlinelibrary.wiley.com/doi/epdf/10.1002/ecy.2728?referrer_access_token=ihwJWPvedALfYrGj8LNST04keas67K9QMdWULTWMo8NV5QroktNaDP7pLpu5LR1ihkAJUy-p8oTXHvvPZT_G05PiA9yRWf7qH25nnbpYnWtVZTy41Roc-o3fefjq9WMxtNP9zCUFBy3K-8jk4IRtpw==
     
    Last edited: 24 May 2019
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  19. birdsandbats

    birdsandbats Well-Known Member

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    Looks like you forgot the scientific names.
     
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  20. DesertRhino150

    DesertRhino150 Well-Known Member

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    I have seen some more ecological research that might be of interest, so I am sharing it here:

    Elephants
    - A study of 30 water-filled footprints of African elephants in Uganda's Kibale Forest recorded 27 families or orders of macroinvertebrates using them as a habitat; the species were dominated by water scavenger beetles and predaceous diving beetles. Species composition in the footprints was influenced by environmental variables such as age and the amount of organic matter present. Further studies with artificial footprints found that there was higher species richness in footprints closer to natural water bodies. The invertebrates quickly colonise the flooded footprints and may use them as stepping stones to reach new habitats.

    The abstract for the paper in question is included below:
    Error - Cookies Turned Off

    - A more recent piece of research on Asian elephant tracks in Myanmar found that the small pools that form in elephant footprints may persist for over a year. Twenty observed footprints contained the eggs or tadpoles of a single species of unidentified frog; the footprints provide a breeding habitat when others are unavailable and also lack the predators of larger water bodies.

    This research is included below:
    https://www.degruyter.com/view/j/mamm.2019.83.issue-3/mammalia-2017-0174/mammalia-2017-0174.xml

    - Staying on the subject of Asian elephants and frogs, a study in Sri Lanka found that 1.7% of 290 piles of elephant dung examined were being used by three species of frogs as shelter. The burrowing frog Sphaerotheca sp. and Jerdon's narrow-mouthed frog Microhyla rubra both only occurred under the dung in the interface with the ground while the ornate narrow-mouthed frog Microhyla ornata only occurred inside piles of dung partially deformed by diarrhoea and still humid inside. Inspections of 180 dung piles of domestic cattle and water buffalo in the same area found no use by frogs.

    The research is included below:
    https://s3.amazonaws.com/academia.e...2f57c06424e44afb866cb5ca7d7eff7347a18b8c32f87

    - A study in southeast Zimbabwe found that wallowing mammals, especially elephants but also rhinoceros, buffalo and warthog are possibly the most important dispersers of small aquatic invertebrates in the area. Laboratory hatching of mud found on rubbing trees by ponds revealed the propagules of 22 invertebrate taxa as well as some aquatic plants.

    This research is included below:
    https://s3.amazonaws.com/academia.e...ad69715bd346d29d7ac200ea5aba9dc4f162018eb9117

    Sympatric mustelids

    - The Baraba steppe-forest in West Siberia is home to four sympatric Mustela species - the stoat, Siberian weasel, steppe polecat and least weasel. All four species co-occur in the same habitat which they use similarly and all are active at the same time of day. Stoats fed chiefly on small rodents (45.9%) and water voles (33.2%), Siberian weasels consumed a similar percentage of small rodents (6.7%) but ate more water voles (49.0%), steppe polecats consumed fewer small rodents (32.3%) but ate more water voles and also took larger rodents such as muskrats, ground squirrels and hamsters while the least weasel subsisted almost exclusively on small rodents. With such strong overlap in habitat use, diet and activity time in this guild, it seems that the niche differences are more subtle. While it has not been tested, the skull shape of the Siberian weasel suggests it hunts chiefly by sound rather than by smell as the other mustelids do while the shape of the steppe polecat's skull allows it to tackle different prey to the other species.

    The paper in question is included below:
    https://s3.amazonaws.com/academia.e...393211fb325296cd36380c4b3ed6cb11ef27aa638ecd3
     
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