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Environment, Ecology & Earth's biodiversity
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Fascinating stuff on how animal hierarchies can influence seed dispersal in a population, from The important role of animal social status in vertebrate seed dispersal
"Because coyote dominance hierarchies affect individual access to carrion (i.e., dominant individuals have greater access than subordinates; Atwood & Gese, 2008; Gese et al., 1996), it is likely that subordinate individuals consume greater amounts of fruit (a secondary food item), transporting substantially greater quantities of seeds than dominant individuals (Figure 1). Because transient (less-dominant) coyotes also have reduced access to ungulate carcasses than territorial (more-dominant) individuals (Gese, 2001), it is likely that resident status is an important predictor of individual fruit consumption, and subsequent seed dispersal, in coyote populations. It may be quite common that subordinate individuals disperse substantially more seeds than dominant individuals within carnivore populations (Box 1) as well as many primate populations where social status is known to dictate individual diet breadth. For example, in Kenya, fungivorous vervets (Cercopithecus aethiops) exhibit rank-dependent diet breadth. High-ranking female vervets females are able to defend fungi, a larger component of high-ranking female diets, due to its abundance in restricted areas (Isbell et al., 1999). As a result, lower-ranking females incorporate significantly more fruit in their diets (Isbell et al., 1999) and are, therefore, likely to disperse greater quantities of seeds than high-ranking females." "Dominant individuals typically defend territories with preferred habitat types, and subordinate individuals generally have less restricted home ranges, sample more habitat patches during a foray, and are more likely to go on extraterritorial forays. Subordinate individuals are consequently more likely to move seeds greater distances and deposit seeds in a broader diversity of habitat types" "Hence, if dominant individuals deposit seeds in habitats with different granivore communities than the habitats in which subordinates deposit seeds, then the probability of post-dispersal seed survival may drastically differ. This contrast may be most evident in group-living canids, like coyotes, where dominant individuals spend more time maintaining territory boundaries, often through scent-marking and scat deposition, than subordinate individuals (Gese, 2001). Because territory boundaries often fall along habitat edges, including roads and trails, seed fate may differ among dominant- and subordinate-dispersed seeds if granivores either avoid or prefer edges." "Recent work on Sardinian warblers (Sylvia melanocephalahas) illustrates that juveniles dispersing from natal territories can provide functional connectivity for plants between isolated habitats by dispersing seeds through the matrix (González-Varo et al., 2019). Hence, the subordinate social status of juveniles in natal territories can be an important mechanism by which seeds may be dispersed long distances and into a greater diversity of habitats than the habitats used by adults (Blitzer et al., 2012; González-Varo et al., 2019). Social dominance in grizzly bear (Ursus arctos horribilis) populations is typically a result of individual size (larger bears are dominant over smaller bears) and reproductive status (females with cubs are subordinate to single males; Ben-David et al., 2004; Gende & Quinn, 2004). Because individual social status affects bear diet and space use (Box 1), juvenile males are likely to become less effective seed-dispersal agents over their lifetime, and females are likely to be most effective seed-dispersal agents during their lifetime when they are rearing cubs. Crocodilian species (order Crocodylia) can also consume large quantities of fleshy fruit, yet their role as agents of seed dispersal is largely unappreciated (Platt et al., 2013). Some crocodile populations can have distinct dominance hierarchies (Garrick & Lang, 2020; Platt et al., 2013; Tucker et al., 1998), and individual social status, which is generally a function of ontogeny and territoriality, can affect movement patterns that may then generate predictable intraspecific variation in seed dispersal (Platt et al., 2013). For example, non-territorial subadult Nile crocodiles (Crocodylus niloticus) exhibit the highest range of movement than all other social classes because they do not maintain distinct home ranges during this life stage (Hutton, 1989). Long-distance movement by socially subordinate subadults that are forced to disperse from natal habitats due to intraspecific competition has also been documented in Australian freshwater crocodiles (Crocodylus johnstoni; Tucker et al., 1998). It is, therefore, possible that socially subordinate, subadult crocodilians provide uniquely long seed-dispersal services." 
12-31-2023, 09:00 PM
( This post was last modified: 01-02-2024, 10:08 AM by sanjay
Edit Reason: corrected the format
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(04-13-2017, 10:20 AM)sanjay Wrote: Top predators play very important role in climate change in the environment they lives.They can bring life back to the place they live. They give more lives then they take. Absolutely, the role of top predators in ecosystems, often referred to as trophic cascades, is a fascinating and vital aspect of maintaining ecological balance. The reintroduction of wolves to Yellowstone National Park is a classic and well-documented example. Wolves, as apex predators, influence not only the population of their prey (such as elk) but also the behavior of those prey animals. This, in turn, has ripple effects on vegetation, which can impact other wildlife and even the geography of the landscape. In the case of Yellowstone, the absence of wolves had led to an overpopulation of elk, which, in turn, resulted in overgrazing of vegetation, particularly along riverbanks. When wolves were reintroduced, they naturally controlled the elk population, allowing vegetation to recover. This, in a domino effect, led to improved habitat for various species, including beavers, birds, and even fish. The revival of vegetation also stabilized riverbanks and altered the flow of rivers, demonstrating the profound impact that a top predator can have on an entire ecosystem. Such examples highlight the intricate interconnectedness of species within an ecosystem and the importance of preserving biodiversity, including top predators, to maintain the health and functionality of natural environments. Videos and documentaries showcasing these ecological transformations can serve as powerful tools for raising awareness about the importance of conservation and the role that each species, no matter how small or large, plays in sustaining our planet. |
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