Non-native trees alter biomass and nutrient availability in mountain streams of the Cape Floristic Region, a global biodiversity hotspot
Simaika, J. (2018). Non-native trees alter biomass and nutrient availability in mountain streams of the Cape Floristic Region, a global biodiversity hotspot. 5th European Congress of Conservation Biology. doi: 10.17011/conference/eccb2018/107916
© the Authors, 2018
The invasion by alien trees of riparian zones may lead to significant alterations in the amount and timing of leaf litter inputs to freshwater ecosystems, consequently affecting stream ecological functioning. Invasive Australian Acacia tree species are among the most harmful of invading species in the Cape Floristic Region (CFR), a global biodiversity hotspot . Blackwattle (Acacia mearnsii) are leguminous nitrogen fixers, making significant contributions to available biomass and nitrogen in their new habitats . To-date the amount, nor the timing of additions of biomass and nutrient are known. This study assessed patterns of leaf litterfall, Biological Nitrogen Fixation and nutrient resorption (N and P) capacities of A. mearnsii and two native co-occurring species in two perennial streams in the CFR. Instream leaf litter decomposition and macroinvertebrate herbivory experiments were conducted. The results indicate significant riparian zone effects in terms of biomass and nutrient input. The annual leaf litterfall of A. mearnsii in riparian zones was nearly nine times greater compared to native vegetation, and A. mearnsii leaves were dropped twice a year, in mid-summer and mid-autumn, whereas natives dropped their leaves only once. Acacia mearnsii also retained significantly higher N concentrations in leaf litter than the native species throughout the year. The co-occurring native species were efficient at resorption of nutrients, on par with global averages. In contrast, A. mearnsii N resorption was low. In stream, invasive species leaf litter decomposed at a significantly faster rate than that of fynbos species, which was explained by differences in litter quality between species. This suggests that the structurally simpler and higher nutrient containing A. mearnsii leaf litter was preferred by macroinvertebrates. This study highlights the potential of a single alien plant species to disrupt multiple ecosystems, and provides insight to the ability of invaders to disrupt vulnerable Mediterranean-type ecosystems by creating their own environment.  Richardson, D.M., Holmes, P.M., Esler, K.J., Galatowitsch, S.M., Stromberg, J.C., Kirkman, S.P., Pysˇek, P. and Hobbs, R.J. (2007) Riparian vegetation: degradation, alien plant invasions and restoration prospects. Diversity and Distributions, (13), 126-139.  Morris, T. L., Esler, K. J., Barger, N. N., Jacobs, S. M. and Cramer, M. D. (2011) Ecophysiological traits associated with the competitive ability of invasive Australian acacias. Diversity and Distributions, 17(5), 898-910. ...
PublisherOpen Science Centre, University of Jyväskylä
ConferenceECCB2018: 5th European Congress of Conservation Biology. 12th - 15th of June 2018, Jyväskylä, Finland
MetadataShow full item record
- ECCB 2018 
Showing items with similar title or keywords.
Distribution of biodiversity in managed landscapes – can remotely sensed data be used to find biodiversity hot-spots? Lövroth, Therese; Hjältén, Joakim; Roberge, Jean-Michel; Olsson, Jörgen; Lindberg, Eva; Dynesius, Mats (Open Science Centre, University of Jyväskylä, 2018)Management of boreal forests for timber production has caused changes in forest structures and disturbance regimes, which have influenced distribution patterns and abundance for a wide range of organisms. The aim of this ...
Increasing temperature and productivity change biomass, trophic pyramids and community‐level omega‐3 fatty acid content in subarctic lake food webs Keva, Ossi; Taipale, Sami J.; Hayden, Brian; Thomas, Stephen M.; Vesterinen, Jussi; Kankaala, Paula; Kahilainen, Kimmo K. (Wiley-Blackwell, 2021)Climate change in the Arctic is outpacing the global average and land‐use is intensifying due to exploitation of previously inaccessible or unprofitable natural resources. A comprehensive understanding of how the joint ...
Tree monocultures in biodiversity hotspots: impact of pine plantations on the mammal assemblages of the Atlantic Forest and the Southern Cone Mesopotamian Savanna ecoregions of South America Iezzi, María Eugenia; De Angelo, Carlos; Varela, Diego M.; Cruz, Paula; Cirignoli, Sebastián; Di Bitetti, Mario S. (Open Science Centre, University of Jyväskylä, 2018)Large scale plantations of exotic trees (mostly Pinus and Eucalyptus) are replacing vast areas of native environments in South America, with still poorly known consequences on local communities. This is particularly worrisome ...
Timonen, Jonna; Gustaffson, L.; Kotiaho, Janne Sakari; Mönkkönen, Mikko (Collaboration for Environmental Evidence, 2011)Background: The concept of Woodland Key Habitats (WKH, small-scaled presumed hotspots of biodiversity) has become an essential component of forest management in Fennoscandian and Baltic countries. There have been debates ...
Elo, Riikka; Penttinen, Ritva; Sorvari, Jouni (Open Science Centre, University of Jyväskylä, 2018)The red wood ant (Formica) nest mounds form in forest landscape diversity hotspots by hosting large amount of invertebrate ant associates. The most numerous associate group, the soil-dwelling oribatid mites, have however ...