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ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris)
ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris)
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ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris)
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While this is information is not specific to tigers, it is most certainly relevant.
 *This image is copyright of its original author Trends in Wildlife Connectivity Science from the Biodiverse and Human-Dominated South Asia Abstract The threat of habitat fragmentation and population isolation looms large over much of biodiversity in this human-dominated epoch. Species-rich South Asia is made particularly vulnerable by its high human density and anthropogenic habitat modification. Therefore, reliably estimating wildlife connectivity and the factors underpinning it become crucial in mitigating extinction risk due to isolation. We analysed peer-reviewed literature on connectivity and corridors for terrestrial mammals in South Asia to identify trends in connectivity research. We identify key research gaps and highlight future directions that may aid efforts to robustly study connectivity. We found a significant bias towards charismatic megafauna and their habitats. Methodologically, although we observed a range of approaches reflecting some of the advances and innovations in the field, several studies lacked data on animal movement/behaviour, leading to potentially biased inferences of how species disperse through human-modified landscapes. New avenues for connectivity research, though currently under-explored in South Asia, offer alternatives to the heavily used but less-reliable habitat suitability models. We highlight the advantages of landscape genetic methods that reflect effective dispersal and are made feasible through non-invasive and increasingly more cost-effective sampling methods. We also identify important gaps or areas of focus that need to be addressed going forward, including accounting for animal movement/behaviour, human impacts and landscape change for dynamic and adaptive connectivity planning for the future. Trends in Wildlife Connectivity Science from the Biodiverse and Human-Dominated South Asia Key points derived:
 (03-31-2024, 09:24 PM)TheHyenid76 Wrote: While this is information is not specific to tigers, it is most certainly relevant. Why have most of the studies and research been conducted on tigers, significantly more so than other megafauna? Because the tiger is an iconic flagship and umbrella species, the tiger leads the ecosystem. As the top apex predator and dominant carnivore throughout its entire range in the wild, tigers are the pinnacle of the food-chain and ecological pyramid. This means the entire ecosystem relies on the state of a healthy tiger population. This is not the case with other megafauna such as leopards, wolves, bears, wild boars, elephants, bovines, etc. This is also why the tiger is the face of wildlife conservation. The conservation of tigers directly leads to the conservation of all other animals in its habitat. The opposite is not the case. Why? because tigers occupy much larger territories than all other animals that share their range, also, the tiger is the only predator in the ecosystem that hunts and regulates the populations of the largest herbivores which can weigh well over a tonne. What does a tiger need? Food, water and habitat, and that's exactly what every other animal needs. So once you provide the tiger, the apex predator, with all these things, rest of the animals in the ecosystem will automatically thrive. Many people don't realize the great importance of conserving top-tier apex predators like tigers. They're vital to nature. Unlike other megafauna such as bears, wolves, leopards, herbivores, etc, the tiger regulates the entire ecosystem and keeps all other animals in check. Tigers often kill and eat other carnivores such as bears, dholes, leopards and sometimes even crocodiles. By doing this, tigers regulate the numbers of other predators in the forest. This is the role of an alpha predator. There are also certain large, dangerous prey species such as adult gaur and wild buffalo, especially full-grown bulls, which cannot be hunted and killed by any other predator, except the tiger. If the tiger goes extinct, which predator would regulate the gaur, rhino or wild water buffalo populations? None. All other predators are physically incapable. If the tiger goes extinct, large herbivores like gaur, wild buffalo and banteng would overpopulate, which in turn, will deplete forest resources and eventually cause the ecosystem to collapse. This is why wildlife scientists, ecologists and biologists primarily focus on conserving tigers in Asia, because of the great importance of the tiger's role in the ecosystem. Ecologists use tiger populations to estimate how well a region is doing with regards to its biodiversity and ecological balance by estimating tiger populations. A large or growing tiger population is an indicator of a healthy ecosystem. Of course, other animals are also important and all play a role in the ecosystem, but other predators like bears, leopards, jackals, dholes, wolves, and crocodiles don't regulate the population of other predators, nor regulate the populations of large megafauna species such as wild water buffalo, gaur, rhino, and banteng. This is solely the tiger's job and what its specifically built to do. Unlike tigers, other hyper-carnivorous (pure) predators like leopards, crocodiles, dholes, and wolves don't hunt everything. There are certain prey species which are off limits due to their massive size, aggression and strength (i.e. adult gaur, wild buffalo, rhino). To also avoid competition with tigers, other pure predators (leopards, dholes, and wolves) will usually prey on small-medium sized prey animals, whereas the tiger usually hunts the largest prey animals and also often kills and eats all other animals (other predators & mammals) in the forest. So overall, the tiger has the greatest affect on the ecosystem. All in all, the tiger is the most important species in the ecosystem (and Asia) to protect and conserve. The extinction of the alpha apex predator would be devastating to the ecosystem.  *This image is copyright of its original author
All correct @Apex Titan but my friend that does not mean 'less charismatic' species should be neglected. Neglect of smaller carnivores like fishing cats can lead to ignorance about them which leads to conflict with humans. Fishing cat-Human conflict is rising in Bangladesh. Even the humble porcupine and the golden jackal plays an important role in the ecosystem.
(05-02-2024, 07:50 PM)TheHyenid76 Wrote: All correct @Apex Titan but my friend that does not mean 'less charismatic' species should be neglected. Neglect of smaller carnivores like fishing cats can lead to ignorance about them which leads to conflict with humans. Fishing cat-Human conflict is rising in Bangladesh. Even the humble porcupine and the golden jackal plays an important role in the ecosystem. I totally agree with you, every single animal plays an important role in an ecosystem. Even insects and rodents play an important role. However, wildlife ecologists and biologists focus primarily on conserving large apex predators like tigers because this particular apex species plays a far greater role and has a much bigger and important impact on the ecosystem. Look at it this way. In all tiger habitats throughout their range, if leopards went extinct, the ecosystem will still thrive because tigers are there. If bears (brown bears, Asiatic black bear, sloth bear, sun bear) went extinct, the ecosystem will still thrive because other ungulates like wild boars will consume the pine nuts, acorns, plants and scavenge on carcasses, and deer and bovines will consume the vegetation. So other ungulates and omnivores will still play the role of a bear. If dholes, wolves, crocodiles and jackals went extinct, the ecosystem will still thrive because tigers are there. Now, if tigers went extinct, it would be devastating for the ecosystem. For reasons I already explained in my previous post. Tigers are the 'saviour' of the ecosystem. This is why biologists and ecologists tend to focus mostly on the conservation of tigers. Having said that, I do think that more studies should also be conducted on other species too. But I can see why the focus is mainly on tigers.
Here's a new article (published in January 2, 2024) 'Khabarovsk game warden creates a taiga chronicle' of an interview with renowned Russian biologist, conservationist & game warden - Alexander Batalov, who shared some interesting stories from his practice and experiences with a correspondent of the Khabarovsk Territory Today news agency.
For those who don't know, Alexander Batalov is one of Russia's leading tiger & bear experts with over 50 years of field experience studying the large predators of the taiga. He is also the Director of the Durminskoye forestry and hunting enterprise. He's spent several decades following the trails and tracking tigers, bears and other predators to study their diet and habits. Alexander Batalov even traveled to Africa – South Africa and Zambia – to exchange his vast experience as a game warden. They are trying to preserve the population of elephants and rhinos. It's a good read for those who are interested in the Amur tigers studied by Batalov in the Durminskoye forest. For those interested in tigers and bears, in this new article / interview, Batalov once again mentioned that the tiger Ochkarik killed and devoured the huge male brown bear 'Chlamyda' or 'Chlamys'. "A huge robber bear named Chlamys really hindered her in this. If Rachel gets an animal for her kittens, he will come and brazenly take the prey. Then the tigress began to growl in a special way - she called for help from the father of her cubs, a tiger named Ochkarik. He came to the rescue and dealt harshly with the offender - he simply devoured him. After all, Ochkarik is a seasoned male."  *This image is copyright of its original author https://todaykhv.ru/news/in-areas-of-the...nce/71709/ https://habarovsk.bezformata.com/listnew...127201098/ Here's a picture of Ochkarik after he had killed and eaten the huge male brown bear; In this picture taken on Batalov's camera trap, Ochkarik's stomach is gorged, after he had eaten the brown bear:  *This image is copyright of its original author There's several (at least 4 articles) interviews of Batalov, a video, and an email from Batalov himself, confirming that the tiger Ochkarik killed and completely ate the giant male brown bear.
Tigers Suppress Dhole Populations.
A recent study determined that tigers suppress dhole pack sizes in India. Dhole packs are smaller in areas with higher densities of tigers, even if there is a higher density of potential prey species. The scientists conducting the study used camera traps to estimate pack size and tiger numbers. In Tadoba Andhari Tiger Reserve (TATT) where tiger density is high, there were 7 dhole packs averaging 6.4 dholes per pack. In Navegaon Naziri Tiger Reserve (NNTR) where tiger density is lower, there were 5 dhole packs averaging 16.8 dogs per pack. Pack sizes were 2.6 times larger in areas with lower tiger density. Both reserves are in a subtropical dry deciduous forest. Leopards are another important large predator in the reserves, and the leopard population is also negatively impacted by tigers. Common prey species in the reserves include spotted deer, sambar, barking deer, nilgai, wild boar, and gaur. Dhole pack sizes do increase in areas with greater prey density, but the abundance of tigers is a significantly greater influence on dhole pack size. Dholes tend to prey on smaller animals in areas with lots of tigers, so they can quickly consume more of the animal before a tiger drives them away from the kill. Tigers depress dhole populations by directly hunting them and by chasing packs away from their kills. The reduced group sizes in subordinate predators are an outcome of predation pressure, low recruitment rates, and reduced energy gains due to the inability to guard kills against the apex predator - the tiger. Tigers totally dominate dholes. The authors of the study saw tigers kill dholes on 5 different occasions and chase dhole packs away and displace them from their kills 23 times. They found no cases of dholes attacking or killing tigers, not even a tiger cub, nor driving them away from their kills. Also, since tigers were eliminated from Laos, dhole populations have increased there. Tigress killed a dhole: *This image is copyright of its original author Dhole pack size variation: Assessing the effect of Prey availability and Apex predator In multipredator systems, group sizes of social carnivores are shaped by the asymmetric intra-guild interactions. Subordinate social carnivores experience low recruitment rates as an outcome of predation pressure. In South and Southeast Asia, the Tiger (Panthera tigris), Dhole (Cuon alpinus), and Leopard (Panthera pardus) form a widely distributed sympatric guild of large carnivores, wherein tigers are the apex predators followed by dhole and leopard. In this study, we attempted to understand the variation in pack size of a social carnivore, the dhole, at two neighboring sites in the Central Indian landscape. We further evaluated local-scale patterns of variation in pack size at a larger scale by doing a distribution-wide assessment across the dhole ranging countries. At the local scale, we found an inverse relationship between the density of tiger and pack size of dhole while accounting for variability in resources and habitat heterogeneity. Larger dhole packs (16.8 ± 3.1) were observed at the site where the tiger density was low (0.46/100 km2), whereas a smaller pack size (6.4 ± 1.3) was observed in the site with high tiger density (5.36/100 km2). However, in a multipredator system, the strength and direction of competition are complex. Therefore, it is imperative to understand behavioral and demographic responses of carnivores to each other, for safeguarding their viable populations and for maintaining ecosystem equilibrium. One such multipredator system found in South and Southeast Asian forests is of the tiger, dhole, and leopard. Wherein, the two big cats are solitary and the dhole is a social canid. Based on their physiological demands and competitive abilities, tigers (180–245 kg) are considered to be top predators followed by leopards (46–65 kg) and dholes (10–21 kg) (Steinmetz et al., 2013). For example, a study conducted in Kuiburi National Park, Thailand; found tiger presence to be solely correlated with prey rich sites, whereas, presence probability of dhole and leopard was a trade-off between prey availability and active spatial avoidance of tigers (Steinmetz et al., 2013). Whereas, the tiger depleted system of Northern Laos has shown a significant increase in site occupancy of dholes, (Rasphone et al., 2019). RESULTS 3.1 Pack size variation We identified seven packs from TATR (Tadoba Reserve) and five packs form NNTR (Navegaon Naziri Reserve). The number of individuals in a pack ranged from 7 to 12 for TATR Packs and 10 to 28 for NNTR Packs. The reported average pack size was 6.4 (1.3) and 16.8 (3.1) for TATR and NNTR, respectively. A significant difference was found between the pack size of TATR and NNTR (t = −3.05, p-value = 0.02) as depicted through box plots (Figure 2, TATR pack size: median = 7, IQR = 4; NNTR pack size: median = 16, IQR = 6).  *This image is copyright of its original author Dhole pack size in response to tiger density (per 100 km2) based on distribution-wide assessment:  *This image is copyright of its original author Dhole pack size in response to prey density (per km2) based on distribution-wide assessment:  *This image is copyright of its original author Across a wide range of taxa from oceanic (Baum & Worm, 2009) to terrestrial ecosystems, competitively inferior predators differ in abundance, distribution, and behavior as a response to apex predator density and distribution (Newsome et.al., 2017; Newsome & Ripple, 2015). Similarly, from the sympatric guild of tiger, leopard, and dhole, various scientific studies depict a significant decline in leopard populations along with the shift in their diet and spatial displacement to fringe areas, after the population recovery of tigers (Harihar et al., 2011; Kafley et al., 2019; Mondal et al., 2012; Steinmetz et al., 2013). Our study also revealed an inverse relationship between the density of tiger and group size of dhole while accounting for variability in resources and habitat heterogeneity. Dhole pack size in NNTR was ~ 2.62 times bigger than the pack size in TATR. The smaller pack size of dholes in a high tiger density scenario could be because of two reasons. Firstly, intense intraguild competition and associated risk of fatal injuries negatively affect dholes in TATR. For instance, loss of experienced breeders due to predation can result in decreased reproductive rate and destabilization in the pack; mortalities of helpers in the pack can result in diminished hunting efficiency and reduced food provisioning for pups; litter loss due to predation events from tiger can result in lower recruitment rates in the pack (Borg et al., 2015; Courchamp & Macdonald, 2001). All these mechanisms would synergistically act to reduce pack size, beyond which a small pack would experience inherent challenges of breeding and survival. Secondly, larger groups can successfully defend their kills and also consume the prey quickly, leaving minimal chances to attract other competitors (Carbone et al., 2005). However, the fact that per capita intake is compromised in larger groups because of sharing carcass with a greater number of individuals, might act as a counteractive selective pressure. Therefore, we predicted that the decision to be in smaller groups is to maximize energy gain while coexisting with a dominant predator by showing differential prey selection in prey size class and to avoid detection over kills. Although interference competition events are difficult to observe in the wild in such a landscape, we collected opportunistic data via direct predation events, that is, tigers killing dholes (n = 5) and occasions when dholes lost their kills to tigers (n = 23), which support our predictions on the relation between the two competing species. Long-term studies on the demography and behavioral ecology of the two species would further our understanding of such intraguild interactions in the landscape. Conversely, low apex predator density in NNTR seems to be operating in a complex two-way mechanism. We predicted that the larger pack size of dholes in NNTR might be an outcome of reduced predation pressure and easy availability of resources. It is observed in multipredator systems that availability of prey resources is key to the coexistence among carnivores. However, external factors like human-mediated disturbances can alter trophic interactions. Declining apex predator population often results in the reduced threat of predation and wider niche availability in terms of food and space for subordinate predators (Green et al., 2019). Such competitive release scenarios lead to higher survival rates of juveniles and subadults which correspond to larger group sizes in subordinate carnivores (Groom et al., 2017). Additionally, larger packs of subordinate predators are also known to be competitively advantageous to suppress the recovery of dominant predators in the system (Periquet et al., 2015). Patterns at local scale were also in concurrence with results of distribution-wide assessment of dhole pack size. We found pack size to be negatively associated with tiger density and positively associated with prey density. However, the effect size of tiger density was stronger than that of prey density. A similar pattern has been observed in the African ecosystem, where lion populations crashed due to human-induced environmental changes while facilitating the spotted hyena population. Spotted hyenas exhibit more behavioral plasticity than lions and have adapted to human subsidies in disturbed habitats. The reduced lion abundance and decreased risk of predator encounter resulted in increased foraging group size, larger clan size, an overall increase in time spent on kill sites, and easy availability of human subsidies for spotted hyenas (Green et al., 2019). Another such trend has been observed between African wild dog pack size and lion densities across temporal scale in Savé Valley Conservancy (SVC), Zimbabwe (Groom et al., 2017). Before lion population recovery, wild dog pack sizes were observed to be large. However, after the population recovery of the dominant predator, the wild dogs suffered a significant decline in survival rates of pups and adults. Competition from dominant carnivores remains one of the major factors that drive densities of other sympatric carnivores in a system. Therefore, to conserve the endangered dhole, it is crucial to understand its response to tigers, another endangered and flagship species. Our study fills some glaring lacunae in the previous understanding of how intraguild competition can potentially limit a subordinate social predator. NNTR and TATR were comparable natural experiment setups that allowed us to understand demographic responses and the consequences of dominance shift between the endangered tropical carnivores. We suggest that the increased pack size of a social subordinate predator seems to be a demographic adaptation to varying competitor densities and availability of a wider niche. This study contributes to the holistic understanding of guild interactions to optimize ecological triage while conserving charismatic apex predators and mid-ranking predators. https://onlinelibrary.wiley.com/doi/full...0%20km2%29 https://www.researchgate.net/publication...x_predator Top-tier apex predators like tigers dominate and regulate or reduce the populations of other sympatric subordinate (mid-ranking) predators such as wolves, bears, leopards and dholes. As I mentioned in one of my previous posts, as the alpha predator, the tiger has the greatest affect on the ecosystem and keeps all other animals of the forest in check. |
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