In the paper by Tylianakis et. al., we mainly discussed about figure 1 and table 1. According to the figure, as you move from a forest to a rice field, the evenness in interactions drops. Also, it was mentioned in class that evenness, complexity, and stability are important to maintain species richness and resilience.
In the paper by Beckmann and Berger, we talked about how urban bears are becoming dependant on humans by scavenging on garbage rather than by foraging for themselves. This poses a threat to bears because when they are becoming adapted to getting “easy” food, they may lose their ability to forage in the wild. One example that we talked about in class was the house sparrow
finch (I think it was the house finch [it’s actually the house sparrow – Madhu]). The house sparrow finch has become so dependent living in urban areas. Because of that, there are no house sparrows finches living in the wild. We also talked about how the European house sparrows finch were declining in Europe because of their dependence on urban areas. The reason for the decline in Europe is due to the changes in human activities.
In the paper by Battin, we talked about ecological traps. One example that was mentioned in the article that was talked about in class was the Cooper’s hawk example. As mentioned, urban areas are a major ecological trap for these birds. Feeding and building nests are not the problem for these birds. The problem is that these hawks, the nestlings, are capable of becoming infected by a pigeon disease. Urban areas are considered an ecological threat because at least 50% of nestlings die, when this is not the case for nestlings in the wild. This Cooper’s hawk example can be an example of the initial stage of adaptation – where the urban hawk population can evolve to become resistant to the disease. If not, the ecological trap may become a sink.
My opinions to these papers is that all of the papers we’ve read were quite interesting except the one by Tylianakis et. al. When reading it, I couldn’t readily understand the figure really well until it was further explained in class. As for the paper by Beckmann and Berger, it was really interesting because I thought about rock pigeon when we were talking about the house sparrow
finch in class. From my current understanding, I have never seen a rock pigeon in the wild. I was thinking that if all people on earth were to disappear, I think this bird would eventually become extinct. In regards to the paper by Battin, it was quite interesting when it was mentioned in class that the urban environment as an ecological trap for hawks could also be an initial stage of settling in a new environment. This is interesting because an ecological trap could just be another term for colonization – since not all species colonizing a new habitat are readily adjusted to that environment.