Literature Review: Pine Marten Recovery: A Tool for Biological Invasive Species Control and Red Squirrel Conservation?
Themes Explored:
- Observed population changes of red and grey squirrel in areas of pine marten recovery.
- Dietary analysis of pine martens.
- Pine martens as a novel predator to grey squirrel, which do not have arboreal predators in their natural environment.
- Effects on resource and disease mediated competition between red and grey squirrels, driven by pine marten recovery.
- Public opinions on pine marten as a form of grey squirrel control.
Key Findings:
Studies indicate pine marten presence suppresses both resource and disease-mediated competition between red and grey squirrels. There was evidence of higher quantities of grey squirrel in pine marten diet in areas where both squirrel species occur. As well as instances of red squirrels demonstrating more cautious behaviour, when exposed to pine marten scent, versus grey squirrel. Studies show pine marten recovery can contribute to grey squirrel control efforts, but as part of a wider strategy and evaluated on a case-by-case basis, where different ecological dynamics are at play. Longer term impacts require further study.
Empirical Paper: Red Squirrel in Mid Wales: A Review of Long-Term Monitoring Data and Recommendations for Future Conservation Management
Themes Explored:
- Outcomes from long term monitoring, looking at frequency of sightings of pine marten, grey squirrel and red squirrel from within the MWRSP focal area and buffer zone. Collected from trapping data, trail cameras and sightings.
- Limitations of data collection, in particular lack of absence data and issues arising from working across a large and remote area.
- Recommendations for future monitoring methods and identifying key knowledge gaps for future research.
Key Findings:
Whilst no statistical significance could be identified on the effects of pine marten presence on red and grey squirrel within the MWRSP area, trends did indicate potential causation between increased frequency of pine marten sightings in 2021 and a decrease in frequency of grey and red squirrel sightings. However, due to the lack of absence data and other inconsistencies, this is tenuous. This highlighted the need for more robust approaches to long-term monitoring. Understanding the genetic health of the population was highlighted as a key action for the project. Given the complexities of the area and habitat, gaining conclusive population numbers would be difficult, but genetic analysis will still provide a useful snapshot of the health and long-term viability of this population of red squirrels.
