citrinella
Well-known member
In the UK, and also reported by a recent paper from Germany, invertebrates have declined sharply in recent decades. I have been making great efforts to try to stop this over the last 15 years or so, establishing wildflower strips and meadows. I thought things were going quite well, with these areas thronged with moths, bumblebees, hoverflies and all sorts I am less than familiar with then ...
In 2015 there was virtually nothing, almost no beasties at all until high summer and even then very few. Apparently moth recorders up and down the UK found it a miserable year. After all my efforts truly dispiriting. Since then things have not been quite so bad. However bird numbers on this farm have declined sharply over the last 10 years or so and I suspect problems during the breeding season - we make great efforts to keep food available all winter so residents should be OK, but birds like yellowhammer have declined massively.
While other factors are also likely to be important - spells of foul weather at nesting have had obvious serious impacts on nests I monitor - I wonder if the reduced availability of invertebrates for chick food could be a major issue.
The other day a neighbour made an observation which woke me up, I don't know if he originated it, but I had not heard it before. With climate change we now get short mild spells frequently in the winter. Sometimes this results in noticeable emergence of masses of invertebrates. However these spells do not offer suitable conditions - duration or resources - for the invertebrates to complete their life cycles, so possibly significant decreases in the potential breeding population could be occurring before the breeding season has even started.
It is easy to see that if these affects are indeed happening on an increasingly common basis populations could be badly affected over a period of decades.
Obviously such effects would not be uniform across species, some species would not react to these mild spells, and hopefully would not be directly affected, though some of those (non-reactors) might be dependent on those that do react, such as by preying on them. Never-the-less, it could be a significant part of the problems that seem to be affecting our invertebrates and causing such frightening declines in their abundance.
Mike.
In 2015 there was virtually nothing, almost no beasties at all until high summer and even then very few. Apparently moth recorders up and down the UK found it a miserable year. After all my efforts truly dispiriting. Since then things have not been quite so bad. However bird numbers on this farm have declined sharply over the last 10 years or so and I suspect problems during the breeding season - we make great efforts to keep food available all winter so residents should be OK, but birds like yellowhammer have declined massively.
While other factors are also likely to be important - spells of foul weather at nesting have had obvious serious impacts on nests I monitor - I wonder if the reduced availability of invertebrates for chick food could be a major issue.
The other day a neighbour made an observation which woke me up, I don't know if he originated it, but I had not heard it before. With climate change we now get short mild spells frequently in the winter. Sometimes this results in noticeable emergence of masses of invertebrates. However these spells do not offer suitable conditions - duration or resources - for the invertebrates to complete their life cycles, so possibly significant decreases in the potential breeding population could be occurring before the breeding season has even started.
It is easy to see that if these affects are indeed happening on an increasingly common basis populations could be badly affected over a period of decades.
Obviously such effects would not be uniform across species, some species would not react to these mild spells, and hopefully would not be directly affected, though some of those (non-reactors) might be dependent on those that do react, such as by preying on them. Never-the-less, it could be a significant part of the problems that seem to be affecting our invertebrates and causing such frightening declines in their abundance.
Mike.