Honey bees see a world of colour through five eyes | Herald Sun
Jul 3, 2017 – Picture: Luis Mata/RMIT … on top of their head, which point at the sky, sense the colour of the ambient light without forming an actual image.
This post is about a paper entitled Conserving herbivorous and predatory insects in urban green spaces that my colleagues Caragh Threlfall, Nick Williams, Amy Hahs, Mali Malipatil, Nigel Stork, Steve Livesley and I published in Scientific Report.
All species in this planet are delicately interlinked to each other in a beautifully complex network of ecological interactions. In cities, insects are key components of urban ecological networks and are greatly impacted by anthropogenic activities. In this paper we examined how insect functional groups respond to changes to urban vegetation associated with different management actions. We set out to investigate how herbivorous and predatory heteropteran bugs were influenced by differences in vegetation structure and diversity in a series of urban green spaces throughout southeastern Melbourne. The studied green spaces included golf courses, gardens and parks.
We looked at how the species richness of herbivorous and predatory heteropteran bugs varied amongst the different types of green space, and the effect that vegetation volume and plant diversity had on trophic- and species-specific occupancy. To this purpose we used a special type of modelling framework, namely ‘multi-species site occupancy models’. The hierarchical structure of multi-species site occupancy models is composed of three levels: a level for the ecological process (e.g. species site occupancy), another for the observation process (i.e. species detectability), and a third to account for the sampling of each species from its metacommunity.
In the paper we report that golf courses sustain higher species richness of herbivorous and predatory heteropteran bugs than parks and gardens, and that at the trophic- and species-specific levels, herbivores and predators show strong positive responses to vegetation volume. However, we also report that the effect of plant diversity is distinctly species-specific, with species showing both positive and negative responses.
Our findings highlight that high occupancy of herbivorous and predatory bugs is obtained in green spaces with specific combinations of vegetation structure and diversity. We point out that the challenge faced by green space managers is how they can boost the conservation value of all urban green spaces for herbivorous and predatory insects through management strategies and actions aimed at promoting synergistic combinations of vegetation structure and plant diversity. We suggest that this will be especially important in large green spaces with simple vegetation structure, and in smaller green spaces such as public parks and residential gardens where a heterogeneity of planting structure and diversity is more difficult to intentionally achieve. We believe that tackling this conservation challenge could provide enormous benefits for all other elements of urban ecological networks, including human city-dwellers.
How did The Little Things that Run the City project get its name?
The Little Things that Run the City has been inspired by Edward O. Wilson’s famous quote:
“…let me say a word on behalf of these little things that run the world”
The quote was part of an address given by Wilson on occasion of the opening of the invertebrate exhibit of the National Zoological Park (Washington D.C., USA). It later appeared in writing format in the first volume of the journal Conservation Biology.
The key objective of Wilson’s address was to stress the urgent need to recognise the importance of insects and other invertebrates for humanity. Almost 30 years ago he was keen to see that efforts aimed at the conservation of biodiversity were beginning to also include non-vertebrate animals. In his words:
“A hundred years ago few people thought of saving any kind of animal or plant. The circle of concern has expanded steadily since, and it is just now beginning to encompass the invertebrates. For reasons that have to do with almost every facet of human welfare, we should welcome this new development.”
In this research collaboration with the City of Melbourne we aim to expand the circle further to also encompass the conservation of insects and other invertebrates in urban environments.
We are inspired to ‘say a word on behalf of the little things that run the city’.
Cover art by Kate Cranney.
On the 16th February 2016, the Urban Sustainability Branch of the City of Melbourne conducted a workshop with a working group of plant, fungi, bird, reptile, frog, mammal, insect and mollusc experts with the objective of identifying appropriate target species for rewilding, monitoring and public engagement in the City of Melbourne. The workshop was undertaken in close collaboration with our RMIT University’s Interdisciplinary Conservation Science Research Group and the Shared Urban Habitat research project of the National Environmental Science Programme – Clean Air and Urban Landscapes Hub.
The ‘Target species for rewilding, monitoring and public engagement in the City of Melbourne’ report aims to summarise the events that took place during the workshop and present its most significant findings, including a list of potential species that could be targeted for rewilding, monitoring and/or public engagement actions in the municipality.