Standish, R.J., Williams, P.A., Robertson, A.W., Scott, N.A. and Hedderley, D.I. 2004. Invasion by a perennial herb increases decomposition rate and alters nutrient availability in warm temperate lowland forest remnants. Biological Invasions 6: 71–82.
While the impacts of invasive weeds on community processes are well studied, comparitively little is known about the impacts of weeds on ecosystem processes. We determined the impact of Tradescantia fluminensis on litter decomposition and nutrient availability in a remnant of New Zealand lowland podocarp-broadleaf forest. We used multiple approaches to demonstrate that Tradescantia increases litter decomposition and alters nutrient availability, effects which could influence the long-term viability of a majority of podocarp-broadleaf forest remnants affected with Tradescantia in New Zealand.
02 March, 2004
Standish (2004): Impact of an invasive clonal herb on epigaeic invertebrates in forest remnants in New Zealand.
Standish, R.J. 2004. Impact of an invasive clonal herb on epigaeic invertebrates in forest remnants in New Zealand. Biological Conservation 116: 49–58.
Tradescantia fluminensis is widespread throughout northern New Zealand and can become the dominant ground cover of forest remnants that it invades. Epigaeic invertebrates were sampled within three Tradescantia-infested plots and three non-infested plots at each of three sites using pitfall traps. Impacts of Tradescantia were apparent despite large differences in invertebrate assemblages among sites. The impact of Tradescantia could be a result of the weed’s tall, dense vegetation structure and associated microclimate, relative to native ground covers.
Tradescantia fluminensis is widespread throughout northern New Zealand and can become the dominant ground cover of forest remnants that it invades. Epigaeic invertebrates were sampled within three Tradescantia-infested plots and three non-infested plots at each of three sites using pitfall traps. Impacts of Tradescantia were apparent despite large differences in invertebrate assemblages among sites. The impact of Tradescantia could be a result of the weed’s tall, dense vegetation structure and associated microclimate, relative to native ground covers.
Moore and Battley (2003): Cockle-opening by a dabbling duck, the Brown Teal.
Moore, S.J. & Battley, P.F. 2003. Cockle-opening by a dabbling duck, the Brown Teal. Waterbirds 26: 331-334.
Many birds feed on bivalves, but only oystercatchers (Haematopus spp.) are known to prise open the shells. Brown Teal (Anas chlorotis), a dabbling duck endemic to New Zealand, were observed opening Common Cockles (Austrovenus stutchburyi) on Great Barrier Island. The teal jack-hammered into the open shells of feeding cockles and quickly scooped out the flesh. Despite having the bill morphology of a typical dabbling duck, they were adept at this feeding method.
Many birds feed on bivalves, but only oystercatchers (Haematopus spp.) are known to prise open the shells. Brown Teal (Anas chlorotis), a dabbling duck endemic to New Zealand, were observed opening Common Cockles (Austrovenus stutchburyi) on Great Barrier Island. The teal jack-hammered into the open shells of feeding cockles and quickly scooped out the flesh. Despite having the bill morphology of a typical dabbling duck, they were adept at this feeding method.
Gillman et al. (2003): Response of forest tree seedlings to simulated litterfall damage.
Gillman, L.N., Wright, S.D. & Ogden, J. 2003. Response of forest tree seedlings to simulated litterfall damage. Plant Ecology 169: 53-60.
Litterfall has been recognised as an important cause of seedling mortality in many forests. However, this is the first study to demonstrate differences in resilience to litterfall among seedling species. Seedling pairs of seven species were selected and one of each pair was pinned to the ground to simulate litterfall damage. Surprisingly, pinned Nothofagus menziesii and Hedycarya arborea suffered few mortalities and grew much faster than unpinned seedlings, whereas pinned Nestegis cunninghamii and Prumnopitys ferruginea suffered high mortalities and survivors grew little. Other species demonstrated intermediate resilience. This variable resilience combined with variability in microsite litterfall risk may contribute to regeneration niche differentiation.
Litterfall has been recognised as an important cause of seedling mortality in many forests. However, this is the first study to demonstrate differences in resilience to litterfall among seedling species. Seedling pairs of seven species were selected and one of each pair was pinned to the ground to simulate litterfall damage. Surprisingly, pinned Nothofagus menziesii and Hedycarya arborea suffered few mortalities and grew much faster than unpinned seedlings, whereas pinned Nestegis cunninghamii and Prumnopitys ferruginea suffered high mortalities and survivors grew little. Other species demonstrated intermediate resilience. This variable resilience combined with variability in microsite litterfall risk may contribute to regeneration niche differentiation.
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