Bees are flying insects closely related to wasps and ants, known for their role in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey and beeswax.
It has been shown from various studies that there are some species of Bumble bees like Bombus L Latreille are able to survive in the anthropogenic habitats. There are the minimum requirements like nest sites, nest building materials such as rodent fur, flowers and grasses for the survival of bumble bees.
These are the sources from which bumble bees collect the pollen and nectar. There are the preferable sites for nesting where bumble bees make nests either in the ground, often in abandoned rodent burrows , or abandoned bird nests , or above the ground or in the tall grasses. The first study related with insects in parks of urban areas showed that these parks serve as a role of island of useable habitat surrounded by an inhospitable sea of development. This is in accordance with theory of island biogeography.
There is relatively the best way to predict the insect abundance and diversity being provided by structurally complex and taxonomically diverse communities of wild and cultivated flowering plants in community gardens. Several studies show that edges and community assemblage of the patches proliferate high ratio of perimeter to area than non-edge adapted species. Insects in fragmented habitats have looked at scales of landscapes which help to predict the species assemblage. Semi natural habitants surroundings correlates with the species richness of trap nesting bees , wasps and their natural enemies and solitary , wild bees at small spatial scales and honeybees at large spatial scales.
An estimate of nest density in different habitats is a prerequisite for estimating bumblebee population sizes, and is directly relevant to making decisions about which habitats to create or conserve to provide more bumblebee nesting sites. Land which is supported by the cities and towns is considered to be free from draining surfaces which are generally termed as the green space which reduce the impact of urbanization.
These green spaces have potential to preserve and create the habitat by lessening the detrimental effects on species assemblage and by retaining the corridors through the urban matrix. Domestic gardens associated with the residential zones form the major component of urban green space. Few of the estimates in the UK cities show that entire urban area of 19-27% is composed by the domestic gardens, so the domestic gardens may play important role in maintaining and conserving the biodiversity in such regions. The role of parks in promoting biodiversity particular species diversity. Biodiversity has a direct link to human wellbeing whereas it also provides an important base for ecosystem functioning and so a range of ecosystem services.
Interdependent relation of bees and plants in Suburban sprawls providing community
It is shown by the studies that bees are the pollinators on which approximately 80% of wild plant species and 75% of cultivated plant species rely for pollination process. It is because of that pollinators and plants depend on their services which coexist mutualistically. Urbanization is vast worldwide and has modified environments. Several studies shows that global urban previous and infrastructure development lead to increase in previous 100 years and population will increase in future. This massive increase in huge lead to expand buildings de vegetating land ultimately causing loss of habitat and extinction of species and biodiversity. But urbanization is not entirely finishing species but it shifts the community structure from one habitat to another habitat. It is focusing on priority of effects on species that serves the ecosystem services such as wild bees that play role in many ways like crop pollination. So several studies reveal that by urbanization and in cities many wild species are thriving. Wild bees may take benefit by combination of vegetation features and human variables that are occurring in urban environment.
Source of survival and Requirements for nectar source
There is a vast variety of ornamental species and exotic plant species in the parks and gardens. In this ecosystem bees would be able to survive and prosper over these species. Community structure can be shaped by providing and presence of some exotic and dominant species. But there is another case in which few studies shows that in urban environment, the dominant species affect the overall structure of whole bee communities.
The presence of parks and gardens in the cities play critical role in conservation and promoting the biodiversity and can also benefit the humans and wildlife. Urban present in community gardens provides various benefits where it improves the values of public health and provides the floral resources in large amount to the pollinators. There are following things that enable the bumble bees to survive are nest sites, nest building materials such as rodent fur and grasses and flowers from which they can collect pollen and nectar. Bumble bees are provided with benefits by availability of a variety and continuity of floral resources in the gardens.
A part from continuity of forage, the sites in which overwintering queens can hibernate and new colonies can be founded by queens emerging from hibernation in spring in nesting sites and these are the essential resources for bumble bees. At their nesting sites, the bumblebees queen are known to fight, so in some cases of landscapes the population size or density can be limited by the availability of nest site. There are the management options for the conservation of bees for example sowing of wildflower strips which are targeted at flowering visiting insects such as bees. To enhance the forage availability for long tongued bumblebees in particular, the current nectar and pollen mixture has been chosen.
High floral density in attracting bees and conserving solitary and wild bees species.
The solitary bees of estimated 24000 exist in vast majority. In temperate regions within the urban landscapes, the solitary bees are dominant and recorded 79% of urban bees there in region of California in their nesting sites. There has been estimation that over 1600 native bee species in California and 250 bee species has to be found in urban areas throughout the state. The gardens present there have more potential to become a more pollinator friendly. It is the one of the feature of many urban landscapes have shown to attract many insect species including bees. Some studies shows that some bees are finding a niche within highly modified and human dominated urban landscapes.
It has been showed that in urbanization, there is not clear perception of response by bees. Their nesting sites are on considerable distances where the bees forage on patches of floral resources. If there is a availability of floral resources and nesting sites exist and the distance between two resources is not too large then the bees would be able to live prolong in urban areas. There was greater abundance of the nesting bees in the urban fragments than in the outlying desert. It was because of higher availability of nesting sites in urban area, native bees of seventy four species were collected in gardens.
It has been shown from the study that the most of the community gardens are particularly characterized by the low or no pesticides use and applications. So the high floral density present in the community gardens provides ultimately the important habitat for urban bee populations. It can be comprehended from the factors that increase or decrease in pollinator abundance and diversity in the community gardens could improve the gardens yields and ultimately helping in the conservation of wild bee species.
Floral resources for reproduction and life cycle
Floral resources are considered to provide the nectar and pollen and are crucial for reproduction and survival in bees at appropriate times. The ability of bees to take enough nutrition and to provide provision to the nest depends upon the availability and productivity of flowering plants for the larval development. There is wide range of plant species on which adult bees may feed on the nectar but may exhibit mesolectic or oligolectic patterns of pollen foraging.
During the specific seasons, the individual lifespan of an adult bee is usually limited to a few weeks emphasizing on managing the bees communities and foraging patterns in appropriate floral blooms with adult flight. Changes being taken by usage and maintenance of urban parks change the available resources to the insects within the parks. Soils are compacted and there is less stability of microclimates. Urban parks leading to decline the native vegetation to landscaping and to the invasive plants. Species continue to exist in the urban parks must be able to utilize the every resource in this new type of habitat
Provides pollination services for bees and their effects on gardens and agriculture productivity.
Insect pollination helps to increase the productivity in 68% of the world’s leading 57 crops and is necessary for the fruit setting in crops including watermelon, vanilla, kiwi, passion fruit, squashes and pumpkins. Even the self-fertile plants can benefit from insect pollination which is capable of fruiting in the absence of pollinators.
These benefits include better taste, increased fruit set, longer shelf life, and more symmetrical shape. These are the plants that provide the host service and bees provide pollination to them. While most studies on pollination services have focused on rural horticultural systems there is no reason to believe that pollinators will be less important in urban systems. Indeed, it was observed that fruit and seed set in cucumbers and egg plants in small urban gardens in Chicago were positively influenced by the diversity and abundance of wild bees. In order to make the productiveness, community gardens such as other horticultural systems require adequate pollination services from a range of insects, the most important of which are likely to be bees.