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Matteson, K. and G. Langellotto (2010). "Determinates of inner city
butterfly and bee species richness." <u>Urban Ecosystems</u>
<b>13</b>(3): 333-347.<br>
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Although urbanization is increasing worldwide, relatively few studies
have investigated patterns of urban biodiversity outside of city parks
and reserves, in urban neighborhoods where people live and work. We
evaluated models including local and landscape factors that might
influence the bee and butterfly richness of community gardens located
within densely populated neighborhoods of the Bronx and East Harlem in
New York City (>10,000 people/km2). The gardens were surrounded by
buildings and limited amounts of green space (3,600400 building units and
10 green space within a 500m radius). Contrary to our initial prediction
that landscape green space might be especially influential in this
heavily urbanized setting, the most highly supported models for both bee
and butterfly richness (based on Akaike Information Criterion) included
just the local, within-garden variables of garden floral area and
sunlight availability. There was marginal support for models of bee
richness including the number of building units surrounding gardens
within a 500m radius (which exhibited a negative association with bee
richness). In addition, perhaps because bees are central place foragers
that may nest within or near gardens, supported models of bee species
richness also included total garden area, canopy cover, and the presence
of wild/unmanaged area in the garden. Generally, our findings indicate
that sunlight and floral abundance are the major factors limiting local
pollinator diversity in this setting. This suggests that rooftop and
other urban habitats might be managed to increase local pollinator
diversity, even if seemingly within heavily developed
neighborhoods.<br><br>
</dl>Matteson, K. C. and G. A. Langellotto (2009). "Bumble bee
abundance in New York City community gardens: Implications for urban
agriculture." <u>Cities and the Environment</u> <b>2</b>(1).<br>
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variety of crops are grown in New York City community gardens. Although
the production of many crops benefits from pollination by bees, little is
known about bee abundance in urban community gardens or which crops are
specifically dependent on bee pollination. In 2005, we compiled a list of
crop plants grown within 19 community gardens in New York City and
classified these plants according to their dependence on bee pollination.
In addition, using mark-recapture methods, we estimated the abundance of
a potentially important pollinator within New York City urban gardens,
the common eastern bumble bee (Bombus impatiens). This species is
currently recognized as a valuable commercial pollinator of greenhouse
crops. However, wild populations of B. impatiens are abundant throughout
its range, including in New York City community gardens, where it is the
most abundant native bee species present and where it has been observed
visiting a variety of crop flowers.<br><br>
<dd>We conservatively counted 25 species of crop plants in 19 surveyed
gardens. The literature suggests that 92% of these crops are dependent,
to some degree, on bee pollination in order to set fruit or seed. Bombus
impatiens workers were observed visiting flowers of 78% of these
pollination-dependent crops. Estimates of the number of B. impatiens
workers visiting individual gardens during the study period ranged from 3
to 15 bees per 100m2 of total garden area and 6 to 29 bees per 100m2 of
garden floral area. Of 229 B. impatiens workers marked, all recaptured
individuals (45%) were found in gardens where they were initially marked.
These results indicate an abundance of B. impatiens workers within New
York City community gardens and suggest that, at least for certain time
periods, many individual workers forage within single gardens. Both
findings suggest that B. impatiens may be an especially important
pollinator of several common crops grown within community gardens and
other urban green spaces that are used for agricultural production.
Studies of other pollinating insect species in urban habitats as well as
the relationship between pollen movement and seed or fruit set will
complement the findings of this study.<br><br>
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