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Animal migration is the relatively long-distance movement of individual animals, usually on a seasonal basis. It is the most common form of migration in ecology. It is found in all major animal groups, including birds , mammals , fish , reptiles , amphibians, insects , and crustaceans .
Animal migration is the relatively long-distance movement of individual animals, usually on a seasonal basis. It is the most common form of migration in ecology. [ 5 ] It is found in all major animal groups, including birds , [ 6 ] mammals , [ 7 ] fish , [ 8 ] [ 9 ] reptiles , [ 10 ] amphibians, insects , [ 11 ] and crustaceans .
The deserts in California receive between 2 and 10 inches (51 and 254 mm) of rain per year. [6] Plants in these deserts are brush and scrub, adapted to the low rainfall. Common plant species include creosote bush , blackbrush , greasewood , saltbush , big sagebrush , low sagebrush , and shadscale . [ 6 ]
Reinforcement is the deliberate introduction and integration of an organism into an area where its species is already established. [1] This mode of translocation is implemented in populations whose numbers have dropped below critical levels, become dangerously inbred, or who need artificial immigration to maintain genetic diversity. [15]
This difference in fortunes was manifested in several ways. Northwardly migrating animals often were not able to compete for resources as well as the North American species already occupying the same ecological niches; those that did become established were not able to diversify much, and in some cases did not survive for long. [ 89 ]
The role of migration in gene flow has also been studied in many species. [7] Parasite loads affect migration. Severely infected individuals are weak and have shortened lifespans. [8] Infection creates an effect known as culling whereby migrating animals are less likely to complete the migration. This results in populations with lower parasite ...
The forests of Northern California are home to many animals, for instance the American black bear.There are between 25,000 and 35,000 black bears in the state. [6]The forests in northern parts of California have an abundant fauna, which includes for instance the black-tailed deer, black bear, gray fox, North American cougar, bobcat, and Roosevelt elk.
Monarch butterfly migration is the phenomenon, mainly across North America, where the subspecies Danaus plexippus plexippus migrates each autumn to overwintering sites on the West Coast of California or mountainous sites in Central Mexico. Other populations from around the world perform minor migrations or none at all.