School of Agriculture, Food and Ecosystem Sciences - Research Publications
Permanent URI for this collection
Search Results
1 - 5 of 5
-
ItemBiotic homogenization in an increasingly urbanized temperate grassland ecosystem(WILEY, 2017-05)QUESTION: How does urbanization and associated declines in fire frequency alter the floristic composition of native temperate grasslands? Does it lead to: (1) biotic homogenization, i.e. compositional similarity between remnants increases; (2) biotic differentiation, whereby similarity between remnants declines, or; (3) clustered differentiation, where similarity between remnants remains unchanged, but composition shifts from the historical state? LOCATION: Victoria, Australia. METHODS: Using site‐level surveys, we examined changes in the floristic similarity of 29 urban grasslands from 1992 to 2013 and compared these changes to those of 63 rural grasslands from 1989 to 2014. Community‐level changes in the representation of key functional traits were also examined in urban grasslands, with traits advantaged following disturbance regime change and urban fragmentation predicted to increase in frequency. RESULTS: Our results supported the biotic homogenization hypothesis in urban grasslands. Compositional similarity between grasslands increased principally because of an increase in commonly shared non‐native species, with change in native composition comparatively minor. However, no evidence of biotic homogenization was found in rural grasslands, with no significant change in overall composition identified. The most urbanized sites had the highest number of non‐native species in both the current and historical data sets, yet non‐native composition over the past two decades changed the most in sites on the urban fringe, becoming more similar to sites closer to the urban core. As expected, following declines in fire frequency and increased urbanization, the overall composition of urban grasslands shifted to taller plant species, while native species capable of vegetative reproduction and exotic species with an annual life span increased in frequency. CONCLUSION: Urbanization was an important driver of biodiversity change in the investigated system, with increasing competition intensity in response to disturbance regime change a likely cause of biotic homogenization. Our results demonstrate that non‐native species are a key driver of biotic homogenization, emphasizing the importance of managing non‐native immigration and maintaining historical disturbance processes once native ecosystems become urbanized.
-
ItemMoving beyond biotic homogenization: searching for new insights into vegetation dynamics(WILEY, 2016-05)Abstract Biotic homogenization has been predicted to occur in cities across the world. However, the empirical evidence has been less than convincing. Lososová et al. explore the middle ground between these two points of view in this issue of Journal of Vegetation Science. They take a more sophisticated approach, linking homogenization to bigger questions of vegetation assembly in urban environments.
-
ItemComposition of the soil seed bank in remnant patches of grassy woodland along an urbanization gradient in Melbourne, Australia(SPRINGER, 2013-10)Urban areas around the world are rapidly expanding, with flow-on consequences for the native plants and animals that inhabit these areas. The impacts of this urban growth are not always immediate, and in the case of the local extinction of plant species may take up to 100–150� years. Understanding how urbanization affects ecological patterns and processes may allow us to minimize the loss of species from these areas through better planning and conservation decisions. This study examined the composition of the soil seed bank in remnant patches of grassy woodland along an urbanization gradient in northern Melbourne, Australia, using an ex-situ glasshouse germination trial. A total of 108 species emerged from the soil seed bank, although a majority of the seedlings were seeds from 19 non-indigenous monocot species. Species richness per plot of emergent seedlings was best explained by average annual rainfall, rather than the degree of urbanization in the surrounding landscape. This indicates that the existing plant community may be responding to a natural productivity gradient. The persistence of 123 indigenous plant species in the existing vegetation, even when the soil seed bank is dominated by non-indigenous monocot species, suggests that these plant communities can exist within urban areas, particularly in combination with appropriate management activities that ensure the continuation of previously occurring natural processes.
-
ItemThe effect of urban ground covers on arthropods: An experiment(SPRINGER, 2014-03)
-
ItemThe future of urban biodiversity research: Moving beyond the 'low-hanging fruit'(SPRINGER, 2013-09)