Science Facing Aliens - Invasive Alien Species in Belgium - Belgian ...

Recommendations

Info

52 # crabs fyke -1 day -1 150 100 50 Liefkenshoek tunnel Rupelmonde Antwerp 0 0 F M A M J J A S O N D J F M A M J J A S O N D J F M 2007 2008 Figure 1. Seasonal abundance of the Chinese mitten crab in the Scheldt estuary. Figure 2. Burrows of the Chinese mitten crab in the left side bank of a freshwater marsh creek in the Scheldt estuary. Inset: mitten crab in the opening of its burrow. 350 300 250 200 150 100 50 # crabs fyke -1 day -1 (Antwerp)
The invasion of ring-necked parakeet (Psittacula krameri) in Europe and Belgium: mechanisms and consequences for native biota. Diederik STRUBBE & Erik MATTHYSEN Evolutionary Ecology Group, Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp Establishment of ring-necked parakeets in Europe In Europe, at least 75 nonnative bird species established feral populations (Chiron et al. 2009) and, due in large part to their popularity as cage birds, parrots (Psittacidae) are well represented as invaders, accounting for about 18 % of Europe’s established exotic avifauna (DAISIE 2009). Among parrots, the ring-necked parakeet is undoubtedly the most successful invader. Although this parakeet originates from mostly subtropical regions in Africa and Asia, it has formed at least 65 populations in Europe (Lever 2005, Strubbe & Matthysen 2009a), with population sizes varying from several tens to several thousands of birds (Strubbe & Matthysen 2007). In order to identify the mechanisms that allow this parakeet to invade Europe, we gathered data on parakeet releases and correlated the outcome of an introduction event with human population density and climatic factors, thereby testing two of the major hypotheses on the establishment success of non-native species, i.e. the ‘human activity’ (Taylor & Irwin 2004) and the ‘climate matching’ hypothesis (Williamson 1996). The former hypothesis states that human activity facilitates the establishment of alien species while the latter postulates that species have a higher probability to establish if they are introduced to regions with a climate similar to that in their native area. We found that parakeet establishment correlated positively with measures of human activity such as human population density, but negatively with the number of frost days, providing support for both hypotheses (Strubbe & Matthysen 2009a). Human activity is a root cause of species introductions (Westphal et al. 2008), but human-dominated habitats are often characterized by abundant food and we argue that this increased food supply could well explain the link between the parakeets’ establishment success and human population density, as food availability is one of the most important factors limiting bird populations and supplementary feeding may enhance breeding success (Robb et al. 2008), thus increasing population persistence probability. The negative relationship between parakeet establishment and the number of frost days indicates that parakeets may suffer from climate mismatch, although population crashes during harsh winter are rare, and establishment failure could also be caused by a reduced breeding performance, e.g. due to a lower body condition. Low temperatures can also impact on avian embryonic development, and further support for the climate matching hypothesis comes from Shwartz et al. (2009), who found that European parakeet populations have a much higher rate of egg infertility than parakeets in the native range (India), or populations introduced to warmer regions such as Israel. Predation pressure, however, is much lower in the introduced regions compared to the native range, and this ‘predator release’ (Liu & Stiling 2006) partly offsets the climate mismatch, allowing the parakeet to flourish throughout much of temperate and Mediterranean Europe (Shwartz et al. 2009). 53
Page 1:
Science Facing Aliens Proceedings o
Page 4 and 5:
Segers, H & E. Branquart (Eds). Sci
Page 7 and 8: Welcome to the World? Non-native br
Page 9 and 10: these geese species exchange betwee
Page 11: References Anselin A., Geers V. & K
Page 14 and 15: 8 variables, hydro-morphological ch
Page 16 and 17: 10 References Bollache, L., Devin,
Page 18 and 19: 12 Figure 1 - USDA hardiness zones
Page 20 and 21: 14 40 35 30 25 20 15 10 5 0 # of bl
Page 22 and 23: 16 Appendix - List of non-native sp
Page 25 and 26: Impact of Fallopia spp. on ecosyste
Page 27 and 28: thermophilous grassland species. Ba
Page 29 and 30: Soil-dependent growth strategy of i
Page 31 and 32: Nr. of flowers/plant 3.0 2.5 2.0 1.
Page 33 and 34: Detection of intraguild predation b
Page 35 and 36: Adaline (µg) ± S.E. 2.50 2.00 1.5
Page 37 and 38: Measuring the impact of Harmonia ax
Page 39 and 40: Unidentified (9/20) Propylea 14-pun
Page 41 and 42: Comparing Fallopia japonica, F. sac
Page 43 and 44: SLA (m²/kg) 30 25 20 15 10 5 0 SLA
Page 45 and 46: Mediterranean container plants and
Page 47 and 48: All species from our survey have in
Page 49 and 50: dangers of uncritically using the t
Page 51 and 52: Water frogs in Wallonia: genetic id
Page 53 and 54: • the distinction between the nat
Page 55: References Berger, L., 1988. On the
Page 60 and 61: 54 Ring-necked parakeets in Belgium
Page 62 and 63: 56 Our models predict a mean number
Page 64 and 65: 58 Strubbe D. & Matthysen E., 2009c
Page 66 and 67: 60 Study area & data collection Lie
Page 68 and 69: 62 cm) and age of the tree and comp
Page 71 and 72: Soil arthropods associated to the i
Page 73 and 74: Table 1. Abundance of soil fauna ex
Page 75: References Armbrecht I., Perfecto I
Page 78 and 79: 72 Status of non-indigenous fish sp
Page 80 and 81: 74 Trends At 487 site-specific surv
Page 83 and 84: Non-indigenous species of the Belgi
Page 85 and 86: 70 60 50 40 30 20 10 0 cumulative #
Page 87 and 88: Brussels Psittacidae: impacts, risk
Page 89: References Anonymous 2005. UK non-n
Page 92 and 93: 86 country, by calculating the numb
Page 94 and 95: 88 raised awareness on the importan
Page 96 and 97: 90 Table 1 - Presentation of the di
Page 99: Science Facing Aliens Proceedings o
show all

Science Facing Aliens - Invasive Alien Species in Belgium - Belgian ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?