•The species composition of true-bug communities changes amongst different types of environmental management regimes.•The species composition of bees, beetles, and flies do not change amongst ...different types of environmental management regimes.•Species richness of all insect taxa was higher when flower species richness, a local attribute, was higher, but to different extents in each insect group.•Insect richness in urban ecosystems are determined by multiple landscape attributes.
Urban green spaces vary in their local and regional attributes, and this variation can have contrasting effects on the ability of urban green spaces to support biodiversity. Here we assess the response of four insect taxa to urban development in Sydney, Australia, using a multiscale approach. We sampled four insect orders (Coleoptera, Diptera, Hemiptera and Hymenoptera) at 19 sites and employed a) multivariate analyses to test the responses of insect communities to environmental management regimes, and b) generalised linear models to determine taxa responses to urban green spaces at local and regional scales. We hypothesised that environmental management regimes (forest, urban forest remnant, and recreational park) affected the species composition of insect communities but found no evidence to support this hypothesis. Only species composition of hemipteran communities responded at this scale, with assemblages in urban forest remnants distinct to those in forests and recreational parks. Conversely, site attributes at local and regional scales had distinct effects on each insect group. While species richness of all taxa was positively related to local flower species richness, they exhibited variable responses to regional attributes such as greenspace proportion and site area. The taxon-specific response to local and regional attributes of urban green spaces suggest that there is no silver-bullet for managing local or regional traits to promote diversity of major insect groups in urban areas. These results highlight the opportunities for managers and planners to develop unique and targeted taxon-specific interventions aiming to enhance urban insect diversity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Urban greenspaces are vital refugia for insect biodiversity, but seasonal fluctuation responses of insect taxa to urbanisation and local attributes of urban greenspaces are not well known. Regions ...with mild temperate climates and winter-flowering plants have active winter pollinators that are often neglected. A thorough knowledge of the seasonally fluctuating ecological needs of insects is essential for adequate insect-friendly greenspace management. Hover flies are cosmopolitan inhabitants of urban greenspaces where they provide multiple critical ecosystem services such as pollination and pest control. Our study uses a multi-scale approach to determine the seasonal effects of urbanisation on hover fly richness, abundance, and assemblages in urban greenspaces. We selected 30 sites along an urbanisation gradient (as measured by human population density) in Sydney, Australia, and sampled each site over a year across seasons. We found that hover fly species richness was higher in winter and spring than in summer, while abundance was highest in winter and lowest in summer. Our results also show that a combination urbanisation and local attributes of urban greenspaces (flower richness, flower abundance, human population density, and proportion of native flowers) combined to affect hover fly species richness and abundance in seasonally dependant ways. Hover flies are especially abundant and diverse during winter- a time of the year when other native floral visitors are less active. Thus, hover flies may be important pollinators of the large community of winter-flowering plants in Australia. Urban greenspaces can be made more hospitable to hover flies by implementing simple management initiatives, such as complementing native floral resources with non-native flowers in periods of scarcity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from ...6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale.
ABSTRACT
Urbanisation is a leading cause of global biodiversity loss, imposing the most rapid and ecologically damaging impacts of any human driven land-use change. Despite the trend of biodiversity ...decline, urban nature provides many health, wellbeing and workplace productivity benefits to city dwellers. Hence, there is an urgent need to return nature to cities not only to conserve biodiversity, but also to maintain human experiences of nature. To meet this challenge, there are currently significant global attempts to re-green cities to improve environmental condition, including restoring habitat for biodiversity. However, many barriers to widespread implementation still exist, including competition for limited space, a lack of technical capacity, and a disengaged community. New approaches to urban restoration are urgently needed that suit the small fragments of space available, and that can deliver multiple benefits not only to conserve urban biodiversity but also to reconnect people with nature. To overcome these challenges, an ‘ecology with cities’ perspective, combining horticultural, ecological and social approaches to urban habitat management and restoration, is needed. Significant opportunities exist for urban ecologists and zoologists to engage with practitioners and the community to co-develop and implement approaches to successfully achieve the aim of creating biodiverse urban environments.
Los bosques secundarios han aumentado su extensión en las últimas décadas; a su vez, han sido propuestos como elementos de conservación. El propósito de este estudio fue evaluar la composición ...vegetal y la diversidad en potreros y bosques (Granada, Cundinamarca, Colombia), para comprobar si los procesos sucesionales demuestran direccionalidad. Se ubicaron seis parcelas de 0.1 Ha del borde del bosque hacia el potrero y hacia el bosque. Para cada parcela se determinó la estructura de la vegetación, diversidad y composición florística. Se encontró que la diversidad de los bosques es significativamente superior a la de los potreros en etapas tempranas de sucesión. Por medio de ordenaciones, el estado sucesional de cada una de las parcelas y se caracterizó observando que la vegetación tiende a agruparse según su edad, evidencia de que la sucesión es un proceso direccional. Dibujando perfiles de vegetación y calculando la densidad de plántulas a lo largo del gradiente bosque-potrero se encontró que el reclutamiento de plántulas no es significativamente diferente entre el borde y el interior del bosque. Por último, se encontró una relación inversamente proporcional entre distancias florísticas y geográficas de las parcelas, señalando la discontinuidad como una barrera a la sucesión del bosque.
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