Biodiversity in California

California harbors special plants and animals than any other country in the United States of America (USA). The San Joaquin Valley in California is a region of immense biodiversity and consists of some endemic species and unique biotic communities. The San Joaquin kit fox is one such species.
The San Joaquin package fox, scientifically known as Vulpes macrotis mutica is endemic to the San Joaquin Valley and some adjacent arid valleys of central California. The package fox was first described and named by C. H. Merriam from a specimen gathered near Tracy, San Joaquin County.
The federal Endangered Species Act designated the San Joaquin package fox as endangered and protected in 1967 (U. S. Environmental Protection Agency, 2013) and as was designated as Threatened by the State of California in 1971.
The males of San Joaquin kit foxes are larger than the females, displaying sexual dimorphism. An average male measures 32 inches in length, 12 inches of this is the tail length. It stands 12 inches at shoulder height and weighs 5 pounds. Its foot pads are small and distinct from other canids in its range.
The average size is approximately two inches long and an inch wide. The foxes have long legs, thin body and the large ears set firmly together. Its nose is narrow and pointed. The tail typically carried little, tapers slightly towards its black tip (U. S. Environmental Protection Agency, 2013).
San Joaquin kit foxes have grasslands and scrublands as their habitats. Oak woodland, alkali sink scrubland, vernal pools and alkali meadow communities may also provide habitats for the foxes ((Bjurlin, 2003, Clarke et al., 2007).
The foxes create dense in these areas for shelter, protection, and reproduction, but in some cases, they can inhabit burrows created by other animals. The dens have many openings and are multi-chambered. Pupping dens are larger in size and may have the litter of prey remains scat, matted vegetation, and fresh paw prints.
A habitat’s soil type is important. The foxes prefer areas with loose-textured soils and sparse ground cover. This kind of soil supports an abundance of prey and facilitates the excavation of new dens. The foxes also prefer relatively flat terrain in washes, drainages and roadside berms. The foxes often reuse old burrows or human-made structures such as culverts and pipes that are small enough in diameter to exclude predators (Clarke et al., 2007).
The foxes predate on species such as the California ground squirrels, white-footed mice, kangaroo rats, pocket mice, San Joaquin antelope squirrels, black-tailed hares, desert cottontails, ground-nesting birds, chukar and insects, and vegetation (U. S. Environmental Protection Agency, 2013).
San Joaquin kit foxes breed at one year of age (U. S. Environmental Protection Agency, 2013), but sometimes do not produce in the first year. Between September and October, the females focus on preparing the pupping dens. Mating can occur from December to March, and the pups will be born after a 48-52 gestation period. The male provides the females food while she is lactating.
The kit fox has carved an important niche for itself in the environment. It acts as a rodent control mechanism as it feeds on the rodents in the valley. It also acts as an ‘architect of subterranean burrows’ making dens in flat to sloping terrain, which in turn provides cover for many other species.
The main subgroups of mammals include the egg-laying mammals, the marsupials, and the placental mammals. San Joaquin kit foxes and the swift foxes belong to the placental subset. They have undergone a succession of radiations as carnivores during the Mesozoic forms. The earliest forms of these carnivores are in the order Creodata based on the scientific classification of organisms, most of which became extinct at the end of the Eocene.
The modern carnivores, such as weasels (Mustelidae), cats (Felidae) and dogs (Canidae), all of which began to diversify in the late Eocene or Oligocene replaced the Creodata carnivore. The adaptable lifestyle of canids helped them survive the dropping temperatures in the Miocene and helped them spread in the Eurasia. The success of their colonization of Eurasia due to three million ago; canids had spread all over Europe (Pleistocene). The red fox established itself at an early stage and gave to the corsac fox, then both Ruppell’s fox and the swift fox. The quick fox then gave rise to the kit fox.
San Joaquin kit foxes adapt well to conditions of their environment. They have structures that help them live in the high temperatures of the desert. First, they do not need to consume water as their varied diet provides them with enough liquid to survive (U. S. Environmental Protection Agency, 2013).
Next, they have large ears set close together which act as radiators and help to cool them down. The ears also provide the perfect hearing; they use them to find rodents and insects underground as well as for listening for their predators (U. S. Environmental Protection Agency, 2013).
Third, their fur changes color in different seasons for camouflage. The kit fox’s fur changes color from tan in the summer to pale gray in winter (U. S. Environmental Protection Agency, 2013).
The foxes have fur on the pads of their paws which gives them better traction in the sandy soil of their habitat and protects them from the hot desert floor (U. S. Environmental Protection Agency, 2013). The kit foxes are also nocturnal. Therefore they are active during the cooler time of the night which helps them conserve moisture. They also have heavily pigmented eyes to protect them from the sun’s glare on the rare occasion they go out during the day.
Foxes are rarely translocated because of well-documented negative impacts, including low survival probability, injury and attempted a return to the area of origin (Bjurlin, 2003). If San Joaquin kit foxes were transplanted to a significantly different environment their chances of survival would be very low (Bjurlin, 2003). The foxes are a desert adapted species preferring areas with sparse ground cover and loose textured soil (Clarke et al., 2007).
For instance, in San Joaquin Valley, the kit fox’s numbers are minuscule most likely because the area was once a vast riparian forest and Tule marsh which later farmers converted to agriculture. These kinds of conditions are not suitable for the kit foxes (Clarke et al., 2007).
Their organ system may not be as efficient in the new environment making them more conspicuous to their predators rather than protecting them. A diet filled with more plants will still help them absorb water from their food as usual, and their fur covered paws would assist them to conserve heat during winter.
The continuing loss, degradation, and fragmentation of the habitat threaten the kit foxes. More than 95% of potential habitat for kit foxes on the San Joaquin Valley floor has been converted to irrigated agriculture or has been urbanized, displacing the kit fox to marginal habitats where populations have always been small. A direct result of the development of the native habitat is the fragmentation of the landscape, which limits dispersal, recruitment and genetic flow between populations.

Refernces

Bjurlin, C. (2003). Effects of roads on San Joaquin kit foxes: a review and synthesis of existing data. In International Conference on Ecology and Transportation (pp. pp. 397-406). Raleigh: Center for Transportation & the Environment, North Carolina State University.
Clarke, H., Duke, R., Orland, M., Golightly, R., & Hagen, S. (2007). The San Joaquin Kit Fox in North-Central California: A Review. Researchgate.
Entriken, K. (2017). San Joaquin kit fox. Online.sfsu.edu. Retrieved 28 February 2017,
U. S. Environmental Protection Agency, (2013). San Joaquin kit fox (pp. 1-2). Washington DC: Endangered Species Protection Program, Office of Pesticide Programs.
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