When most people think about drought, I suspect, they visualize crispy, dry vegetation and dusty landscapes – the Dust Bowl, in other words. Or they might think about fallow fields and withering crops. But like most things, drought is much more complex. And we’re in one now, at least here in the Sierra foothills.
Rangeland livestock producers are often the first people to feel the impacts of drought. Even though the hillsides where we’re grazing our sheep outside of Auburn appear lush and green, we are definitely in a critical position. We’ve measured just 0.03 inches of rain since January 29 – and there’s nothing forecasted in the next 14 days. We’ll likely go through February with just one percent of our long term monthly average – and we’ll start March at just over half our year-to-date annual average.
We had a great December and a decent January, but the warm temperatures and dry weather of February are concerning. The warm temperatures are bringing the blue oaks on our rangeland out of dormancy. The longer days are encouraging grass growth, and the north wind has drawn moisture out of the soil. While our grass growth has been fairly normal to date, the depletion of soil moisture – without rain to replenish it – will mean that our annual grasses will mature earlier than usual. Earlier maturing grass has several impacts. As our annual grasses make seed-heads, they become less palatable to our sheep. Equally as important, these plants will mature earlier – which means they don’t produce as much biomass.
We time our production calendar to match grass growth with the feed demands of our sheep. Once the ewes begin lambing – sometime before the end of the month – their forage intake nearly doubles. If our weather stays dry – and our forage matures earlier – we’ll move through our winter pastures more rapidly. We have enough grass ahead of us to get through lambing, but it might impact the forage we save for next fall.
When you boil down our responsibility as ranchers, it comes to matching forage demand (stocking rate) with forage supply (carrying capacity). We’ve been building our numbers up since the 2011-2015 drought; we’re realizing this winter that we may have overshot our carrying capacity. We’ll lamb out the ewes we have; we’ll think long and hard about how many sheep we can carry through this coming fall.
Perhaps the biggest challenge presented by our changing climate is that the extremes have become more extreme. Since we’ve lived in Auburn, our rainfall has varied from 19.99 inches (in 2007) to 62.97 inches (in 2017). While the timing of our precipitation is as critical as the amount (in terms of grass growth), the variation from one year to the next makes it difficult to calculate how many sheep our grasslands can support. That’s why rangeland drought is different….