This paper gives a detailed view on extinction that is threatening almost all world species. Biodiversity and biodiversity hotspots have become a major national and international concern. This paper presents an analysis of California Floristic Province and the way human activities have threatened this habitat. To explain the past and existing threats to natural habitats and species occupying them, I have used several sources of information including books and journal articles.
Currently, life is facing a crisis of planetary and historical proportions. Many developed countries in the North are faced by threats posed by unsustainable consumption while high poverty status in the third world countries is threatening natural resources. Biodiversity is defined as a variety of different living organisms within a common habitat or a biological diversity contraction. Generally, biodiversity may be divided into three major fields, inter alia, genetic, species and ecosystem biodiversity (Thorne, 2002).
On the other hand, a biodiversity hotspot is a region with a significant biodiversity reservoir that is under serious human threat (Markov & Korotaev, 2008). For a region to be considered a biodiversity hotspot, it must have at least 1500 or 0.5% species or forms of endemic vascular plants, and have lost more than 70% of its natural vegetation. Globally, there are only 25 areas which meet the two qualifications. Some of these areas include Caribbean Islands, Mesoamerica, Madrean Pine-Oak Woolands, Atlatic Forest, Tropical Andres and Cerrado among many others. These areas hold approximately 60% of world’s reptiles, plant, birds, mammals, amphibians, and plants species (Jeffrey, 2004).
Biodiversity crisis is usually characterized by extinction, which is the gravest process concerning this topic. Extinction is thought to be natural, but artificial human acts have promoted the state of extinction in biodiversity hotpots by more than a thousand times. Several mass extinction cases have occurred in the world with the last one being the extinction of dinosaurs (Thorne, 2002). In this paper, California Floristic Province will be used as a case study to illustrate the threats that human activities are posing to biodiversity hotspots.
California Floristic Province
California Floristic Province (CFP) is located along the North American Pacific coast (Jeffrey, 2004). CFP covers a surface area of 293,804 km2, which includes more than 70% of California, some areas of south-western Oregon, parts of Northern Baja California, and western Nevada. To the north of this province lies a rocky mountainous region; its boundary is vague and not properly defined. This province takes a major part of California State but excludes the Great Basin, Modoc Plateau and the deserts in southern regions of the state. In Oregon, California Floristic Province includes cape Blanco, rogue watershed and coastal mountains. In Nevada, it embraces some parts such as Sierra, parts of Lake Tahoe, and a small part of Reno-Carson City. Finally, in Baja California, CFP includes chaparral forests and belts of Sierra San Pedro and Sierra Juarez, Guadalupe Island and coastal areas of El Rosario (Hickman, 993).
According to Hickman (1993), CFP is one of the largest world’s biodiversity hotspots because of an unusually high number of endemic plants. It is approximated that 8000 different plant species are presented in this region with more than 3400 taxa. Due to the human quest for westernization and development within this region, CFP lost more than 70% of its natural vegetation (Hickman, 1993). This region is located in Mediterranean climate zone with cool and wet winters and hot, dry summers (Hickman, 993). Most of the coastal regions of CFP are moderated by the bordering Pacific Ocean, and thus experience extremely cool summers. The ocean fog in these coastal regions supports Redwood forests and other aquatic habitats (Allan, 1992).
Human Needs that Endanger California Floristic Province
Allan (1992) explains that America is one of the nations that have undergone the path of western civilization, development and westernization. The high rate of economic development in the U.S.A. has encouraged intensive agricultural production and urban expansion. For instance, the California State is currently the best in commercial farming, generating more than half of agricultural commodities consumed locally in the U.S. A. California’s economy is ranked as one of the top seven best economies in the world. Besides, the region has a very high population that was estimated to be 35 million people according to 2002 statistics. Due to this, the state has the highest growth rate in the United States of America. Some of the direct pressures on CFP from this community include pollution, urbanization, strip mining, habitat encroachment, road construction, logging, livestock grazing, and forest fires.
California State, being a commercial agriculture center in the U.S., has made use of genetically modified crops and hybridization. In animal husbandry and generally agriculture, agrarian revolution encouraged farmers to make use of hybridization to enhance their yields. Hybridized species and breeds normally originate from developed nations and undergo further hybridization with local varieties in developing nations. These developments in agriculture have come up with special breeds of plants and animals that are resistant to local diseases and climate. Hybridization has led to the collapse of several natural species of plants and animals, and, in turn, it has led to genetic pollution and genetic erosion. Scientists have proved that genetic pollution and erosion are destroying endemic genotypes, and eventually some genetic materials will become extinct (Bachelet et. al., 2003).
According to Bachelet et al. (2003), these human population pressures have made California state one of the five most ecologically degraded areas globally. The conversion of natural species habitats to grazing lands, exotic plants invasion and urban development pressure has reduced the vernal pool habitats and native grassland. The region was rich in biodiversity some years back but now what has remained is approximately 1% of its natural extent. The redwood forests that naturally occupied more than 800,00 km2 of CFP have been greatly reduced to 15% of their natural habitat due to the logging operations. Some other highly threatened zones are the riparian woodlands, sage scrub and wetland which have reduced to at most 10% of their original area. The wetlands have been polluted by water diverted for agriculture purposes, land fillings, residential and industrial needs. This has resulted in subsequent reduction of waterfowl, fish, and shellfish populations which fully depend on this habitat.
People living around CFP consume available resources at an alarming and unsustainable rate threatening their existence in the foreseeable future. In this case, such resources are said to have been overexploited. Some of the major causes of overexploitation are too much logging, overhunting, poor soil conservation measures and illegal trading in wildlife commodities. More than 25% of fish are overfished on a global scale to a level that cannot sustain their yields due to a significant drop in biomass. Intensive grazing, logging and development continue to threaten riparian forest, while the sage scrublands are threatened by commercial development, housing, and the off-road vehicles (Allan, 1992).
These activities have greatly destroyed the natural habitat and, in particular, the increased road constructions in areas around and through California Floristic Province have raised civil society concern. It is one of the factors that are greatly contributing to human encroachment, increased extraction of resources and a further biodiversity threat in this hotspot. Habitat destruction is one of the key issues in extinction of biodiversity, mostly in tropical forests. Some other factors contributing to loss of natural habitat include deforestation, overpopulation, global warming, water, air, and soil pollution (Bachelet et al., 2003).
There is a very close relationship between the species number and the habitat size. Species living in the ocean region and lower latitudes and, particularly, big-sized ones are very sensitive to habitat area reduction. Some nations lack property rights or have lax regulatory enforcement, which leads to a serious biodiversity loss. In 2004 National Science Foundation conducted a study which established that genetic diversity and biodiversity are co-dependent. This means that particular species diversity can thrive only in proximity to the other diversity within that particular species. Removing one of these conditions breaks down the cycle, allowing the community to be dominated by a particular species (Jeffrey, 2004).
Bachelet et al. (2003) further explains that another serious human activity that has threatened natural habitat is the introduction on invasive species in CFP. Invasive species is a term used to refer to organisms that breach the natural habitats of others and, in most cases, constrain them. Natural barriers such as seas, rivers, mountains, oceans and deserts enable individual species evolution, thus encouraging biodiversity. Without these natural barriers, invasive species occupy fresh territories, thus supplanting the original or native organisms by making use of resources that sustain the species or occupying new and better territories. If well designed, such invasions can reduce biodiversity. However, human activities in this region have been the root for invasive species living within their barriers. Human beings have introduced invasive species for food and several other purposes. Human activities, therefore, have necessitated species migration to new areas, which makes them more evasive.
Threatened Species in California Floristic Province
CFP unusually holds a large number of different species. Just as explained above, this province including the coastal region holds unique varieties of Redwood plants, fish reptiles and several other species of aquatic organisms. This region is, however, known for having unique plant communities. According to Allan (1992) several botanists have made efforts to put the plants into distinct vegetation species and groupings. As a result, these plants have been categorized into three major groups according to their geographical positions.
The Cismontane region includes vegetation in the western region of CFP (Sierra Nevada) or the northern regions of Transverse Ranges. The Cismontane region has plants such as coastal prairie, coastal strand, chaparral, freshwater mash, and riparian woodland. Transmontane and Montane plants are located in the rain shadow region of Transverse Ranges (Hickman, 1993). Montane region is a habitat for alpine fell field, subalpine forest, montane meadow, montane chaparral and montane coniferous forest. The Transmontane region has such plants as sagebrush, shade scale, juniper woodland and shad-scale scrub. CFP hotspot has a very high level of plant endemism compared to the animals because out of the 7031 species or subspecies of plants in this region 2153 taxa are endemic. On the other hand, 24.7% or 8000 km2 of the natural and original plants habitat is presently still in its pristine conditions (Thomas et. al., 2007).
According to Thomas et. al. (2007), CFP holds 2120 species out of the 3500 vascular plant species found in the world. A high rate of plant endemism in this hotspot is due to its natural climate, topography, soils and geology. The total number of vascular species found in this province is bigger than the number of species in both north-eastern and central parts of the United States and Canada, which is ten times the size of California hotspot. Within this hotspot, there are four sub-regions that are regarded as centers of high plant species diversity. These sub-regions are Transverse Ranges, Sierra Nevada, Klamath-Siskiyou, and the coastal region (Thomas et. al., 2007).
In addition, the North Coast and Central regions of the California hotspot holds serpentine habitats that occur in fault zones. Because of the physical and chemical soil characteristics in this region, the habitat provides very poor nutrients to the species, thus leading to poor establishing of diverse flora. Botanists estimate that the endemic serpentine plants in this region represent 11% of the U.S. and Canada endemic serpentines. California hotspot provides a favorable habitat for giant sequoia. Giant sequoia, presently found in Sierra Nevada range, is the only supposed massive species to have lived on earth. It grows as tall as 75 metres and covers a circumference of more than 30 metres (Frey et. al., 2004).
This province has a large number of endemic vertebrates since out of the 340 recorded endemic bird species California Floristic Province alone holds 10 species. On the other hand, this area is the leading habitat of endemic bird species in the U.S.A. According to the definitions of Birdlife International, CFP has two endemic Bird areas (Thomas et. al., 2007). The Guadalupe Island provides a native habitat for organisms such as Guadalupe junco, California condor, and Guadalupe storm-petrel. On the other hand, this region holds about 20 endemic mammals out of the 150 mammals present in the U.S.A. Since the arrival of white settlers in California several mammal species found in this province have greatly reduced in numbers or gone extinct. These mammals include grey wolf, jaguar, grizzly bear and bison (Thomas et. al., 2007).
Frey et. al. (2004) explain that in CFP approximately 70 reptiles are threatened including the two reptiles found in Cedros Island only; the diamond rattlesnake and horned lizard. Other reptile species such as the red-diamond rattlesnake, ring-neck snake, and the nose snake have fragmented numbers or very low population. Amphibians are the most endemic species in this province. Out of the 100 native amphibians in California Floristic Province, a half can be found presently. The Batrachoseps salamander genus, which includes San Gabriel Salamander discovered recently in Los Angeles, is in great danger. Other endemic salamanders in this region are Aneides genus and tiger salamander (Thomas et. al., 2007). The coastal regions of California Floristic Province have over 70 species of inland fishes. The landlocked species in the mountains to the north of this province might get extinct in the near future if fishing is not controlled within the region.
This hotspot possesses an impressive diversity of invertebrates as it is home to more than 28000 insect species, out of which 9000 are endemic. These endemic species represent approximately 30% of insects in both Canada and U.S.A. It is worth noting that urbanization in the United States has necessitated the mutation of some of the native insect species into the new and more resistant ones (Thomas et. al., 2007).
Measures to Conserve Biodiversity Hotspots
There is an urgent need for biodiversity hotspot conservation measures. Apart from taking actions that will conserve the existing biodiversity hotspots, measures should be put in place to ensure that no other hotspots come up. Most developing nations have inadequate finances, which limits their ability to take care of game parks and national reserves. In most of these countries, expenditures are below 5% of the finances deemed necessary to conduct hotspot conservation measures (Snyder, 2000).
Several global agreements have been signed to protect biodiversity hotspots. For instance, the Convention for Biological Diversity gives all sovereign nations a right over biological resources. This agreement urges all sovereign countries to adopt the whole range of possible measures which will ensure biodiversity conservation and development of biologically sustainable resources and share fruits of their biological efforts. The countries which give room for collection of biological or natural products are entitled to a share of the benefits of this activity rather than allowing the exploiting institutions or individuals to capture the benefits privately (Snyder, 2000).
In the U.S.A, this threat is regulated by both the state and federal government as well as civil organizations. It is, however, discouraging to note that a very small percentage of the area is being protected. The U.S. A. has enacted laws, treaties and commissions which, if fully implemented, will be very effective in terms of taking care of the endangered species in all of the biodiversity hotspots in the country. Such treaties as International Whaling Commission and Convention on International Trade in Endangered Species have played a great role in eliminating trade in endangered species. The Endangered Species Act in the country is designed to explicitly eliminate anthropogenic extinctions. In practice, the act has successfully lowered the extinction rates and has conserved several endemic species such as the bald eagle, the alligator, and the gray whale. If this treaty had been enacted much earlier, species such as Louisiana prairie vole, Carolina elktoe mussel, and Hawaiian plants would still be existent to date (Snyder, 2000).
Additionally, the U.S. has strengthened both economic and legislative disincentives on state, national, and international levels. At the international level, the country has designed measures that will put a lot of pressure on nations which will fail to comply with the legislation. Incentives such as ecosystem service payment are provided by habitat protection bodies at both the state and federal level. These bodies fund communities that reside near biodiversity hotspots or conservation regions, thereby encouraging them to view this conservation move as profiting and appealing (Snyder, 2000).
Several nations have responded to the international call for biodiversity conservation. For instance, Australia has initiated laws at a national level directed towards biodiversity conservation. By these laws, the protection of threatened species has been guaranteed, and they have properly defined species that should be protected due to extinction threats. Laws that govern gene pools were enacted several decades ago in many regions. These laws govern plant breeding and domestication. Genetic engineering advances in the country have led to enactment of tighter laws that govern the distribution and use of gene patents, GMOs and process patents (Jeffrey, 2004).
Some of the crucial measures implemented by international civil organizations include the Ecosystem Partnership Fund (EPF). EPF is a worldwide conservation program that provides both technical and financial assistance to civil societies which develop projects directed towards conservation of the earth’s natural animal and plant habitats. Such habitats include biodiversity wilderness, threatened marine areas and biodiversity hotspots (Jeffrey, 2004).
The World Wildlife Society has come up with a system called Global 200 Ecoregions. This system has a primary responsibility to select threatened ecological regions and take measures to conserve the areas including 3 freshwater, 14 terrestrial, and 4 types of marine habitats. These regions are chosen based on their taxonomic uniqueness, endemism, species richness, and unusual evolutionary and ecological phenomena. All the 25 biodiversity hotspots have at least two ecological regions (Snyder, 2000).
Birdlife International has come up with approximately 218 areas where birds are endemic. Each of these areas holds at least two birds which cannot be found anywhere else in the world. Besides, Birdlife has identified 11000 important bird habitats that require urgent conservation measures. Measures are put in place to make sure that these birds are protected from any possible threats to their existence. Plant Life International has designed several programs targeted at identifying endemic plants which need protection (Jeffrey, 2004).
Several conservation groups and large scientific organizations have come up with an initiative called Alliance for Zero Extinction (Snyder, 2000). These two groups combine efforts focused on protection of all the endemic species globally. As a result, 595 sites have been identified, and measures to protect them have been implemented. On the other hand, National Geographic Society has come up with a hotspot global map that contains biodiversity hotspot metadata including conservation measures which can be used (Snyder, 2000).
Despite the fact that governments have tried to protect biodiversity hotspot, individuals should understand that it is done for their own benefit. For protection to be more effective, individuals living around these regions should be directly involved. Rules to govern the threat should not be punitive but rather corrective. Human activities are threatening the existence of important biodiversity in the world through urbanization and the need for more settlement space. It is important that all these activities are done in a sustainable manner to ensure that the future generation will also enjoy biodiversity.