Knowing the causes of biological invasion success can be relevant to combat future invasive processes.The recent invasion of the horseshoe whip snake Hemorrhois hippocrepis on the island of Ibiza provides the opportun...Knowing the causes of biological invasion success can be relevant to combat future invasive processes.The recent invasion of the horseshoe whip snake Hemorrhois hippocrepis on the island of Ibiza provides the opportunity to compare natural history traits between invasive and source populations,and to unravel what makes this snake a successful invader that is threatening the only endemic vertebrate of the island,Podarcis pityusensis.This study compares the basic reproductive traits of mainland native and invasive populations of the snake.Our results revealed that invasive populations were characterized by female maturity at a smaller size,extended reproductive period,and much lower reproduction frequency compared to the native population.In contrast,some major reproductive traits--the abdominal fat body cycle,clutch size,hatchling body size,and hatchling body condition,did not differ between the two populations.Some of these results must reflect the environmental differences in the recently invaded island with respect to the source area,and overall plasticity of reproductive traits.Plasticity is evolutionarily interesting,and may aid the succesful growth of this species in their invasiveness of Mediterranean islands like Ibiza.The most significant finding is that this expression of phenotypic plasticity occurred rapidly in this invasive population,within a period of 14 years maximum.Our results on the reproduction ecology of the invasive population were not conclusive regarding the factors determining the invasiveness of the snake and pointed to alternative causes.展开更多
The regime of disturbance with natural or anthropogenic origin can lead to the destabilization or even to a mass mortality of benthic communities. Due to the heterogeneity of the disturbance there is a formation of pa...The regime of disturbance with natural or anthropogenic origin can lead to the destabilization or even to a mass mortality of benthic communities. Due to the heterogeneity of the disturbance there is a formation of patches in different stages of ecological succession. The aim of this study is to follow and describe the resilience in artificial disturbed sediment in a polluted bay in Rio de Janeiro. The sediment was collected, sterilized and placed inside corers (10 cmdiameter ×15 cmheight) in the same place where it was collected. We allocated the samples in two structures, the difference between them was that one was placed closed to the bottom and the other was placed50 cmheight. We found 2352 organisms distributed in 14 taxons. The class Polychaeta and the order Amphipoda showed the highest density in all the survey and treatments. We identified the factors influencing the scenarium: different mechanisms of dispersal, the position of the structures and life history of each group. Disturbance can be the main cause of the patch’s diversity found in estuaries and coastal areas. Because of this, monitoring of selected areas becomes an important tool to understand the regime of disturbance as a key factor structuring benthic communities in soft sediment, also suggesting a metapopulation dynamics.展开更多
基金the Consell Insular d'Eivissa,Govern de les Illes Balears[grant numbers 54/2013 and 21/2015—AGRICULTURA].
文摘Knowing the causes of biological invasion success can be relevant to combat future invasive processes.The recent invasion of the horseshoe whip snake Hemorrhois hippocrepis on the island of Ibiza provides the opportunity to compare natural history traits between invasive and source populations,and to unravel what makes this snake a successful invader that is threatening the only endemic vertebrate of the island,Podarcis pityusensis.This study compares the basic reproductive traits of mainland native and invasive populations of the snake.Our results revealed that invasive populations were characterized by female maturity at a smaller size,extended reproductive period,and much lower reproduction frequency compared to the native population.In contrast,some major reproductive traits--the abdominal fat body cycle,clutch size,hatchling body size,and hatchling body condition,did not differ between the two populations.Some of these results must reflect the environmental differences in the recently invaded island with respect to the source area,and overall plasticity of reproductive traits.Plasticity is evolutionarily interesting,and may aid the succesful growth of this species in their invasiveness of Mediterranean islands like Ibiza.The most significant finding is that this expression of phenotypic plasticity occurred rapidly in this invasive population,within a period of 14 years maximum.Our results on the reproduction ecology of the invasive population were not conclusive regarding the factors determining the invasiveness of the snake and pointed to alternative causes.
文摘The regime of disturbance with natural or anthropogenic origin can lead to the destabilization or even to a mass mortality of benthic communities. Due to the heterogeneity of the disturbance there is a formation of patches in different stages of ecological succession. The aim of this study is to follow and describe the resilience in artificial disturbed sediment in a polluted bay in Rio de Janeiro. The sediment was collected, sterilized and placed inside corers (10 cmdiameter ×15 cmheight) in the same place where it was collected. We allocated the samples in two structures, the difference between them was that one was placed closed to the bottom and the other was placed50 cmheight. We found 2352 organisms distributed in 14 taxons. The class Polychaeta and the order Amphipoda showed the highest density in all the survey and treatments. We identified the factors influencing the scenarium: different mechanisms of dispersal, the position of the structures and life history of each group. Disturbance can be the main cause of the patch’s diversity found in estuaries and coastal areas. Because of this, monitoring of selected areas becomes an important tool to understand the regime of disturbance as a key factor structuring benthic communities in soft sediment, also suggesting a metapopulation dynamics.
