Changes in food resources and conservation of scarab beetles: from sheep to dog dung in a green urban area of Rome (Coleoptera, Scarabaeoidea)

Abstract

The aim of the research was to show how a change in land use influences the structure of a dung beetle assemblage and affect its\ud conservation. In the Pineto Urban Regional Park (Rome), dog dung is the sole food resource currently available for scarab dung\ud beetles, after the recent removal of wild and domestic herbivores. A one-year sampling was conducted to study the scarab assemblage\ud in dog scats (1999) and to compare it with the previous assemblage associated with sheep droppings (1986). Richness, evenness\ud and similarity parameters were compared between the two allochronic assemblages. From sheep to dog dung, an impoverishment of\ud the total richness was observed (from 19 to 9 species) together with an increase of individuals (by 7 times). Dog dung harboured 20%\ud of the current scarab dung beetle fauna of Rome, probably as a consequence of the dog mixed diet, rich in cellulose. Both the communities\ud showed a high percentage of tunnellers, probably because of the food shortage and, for dog scats, of the high dehydration\ud rate. A comparison with other Roman scarab communities enhanced that: (1) the change in food resource determined a higher difference\ud in species composition respect to other parameters (size and habitat diversity); (2) dog dung provided a temporary refuge for\ud species that otherwise may encounter local extinction in urban environments.\ud 2005 Elsevier Ltd. All rights reserved.\ud Keywords: Urban ecology; Community ecology; Biodiversity conservation; Food resources; Dung beetle assemblage

City “Green” Contributions: The Role of Urban Greenspaces as Reservoirs for Biodiversity

“…Interestingly, Tecajetes sheltered a high proportion of copro-necrophagous beetles (62.5%) and bats (57.1%), while we recorded 54% of the total ant species in Berros. This underlines the value of small greenspaces for certain groups that benefit from managed, disturbed, and open areas, where resources are more abundant for them [83][84][85]. It is noticeable that among Berros, Tecajates, and San Roque (the three smallest intra-urban greenspaces), the latter was the one with lowest values for most studied taxonomic groups, noticing that although this is a lightly managed and unvisited greenspace with cloud forest elements, its contribution to local biodiversity is relatively low.…”

Impacts on Insect Communities and Species

“…Several surveys of dung beetles in more-or-less urban areas have probed the capability of the beetles to achieve this, and noted the loss of species from the earlier assemblages. Thus, in the large (240 ha) Urban Regional Park of Pineto, Rome , an apparent response to reduction of sheep grazing giving way to a predominance of dog dung was reduction of species richness from 19 to 9 dung beetle species, but with overall abundance increasing substantially (Carpaneto et al 2005 ). The surveys compared were from 1986 (when the park was intensively grazed by sheep before this was reduced in 1989 with the park becoming a public recreational area) and 1999 (when it was dominated by dog dung).…”

Selected Urban Threats to Insects

“…In Rome , Fattorini ( 2011 ) recorded increased density of insectivorous bird populations as a cause of native insect declines. Following Carpaneto et al ( 2005 ), he noted the Hooded crow ( Corvus corone cornix ) and European starling ( Sturnus vulgaris ) as amongst notable opportunist omnivores, but also that raptors fed on beetles. Tenebrionidae were an important food source for the Kestrel ( Falco tinnunculus ) and Litle owl ( Athene noctua ) (Fattorini 2001 ).…”