Early Spring?

I have been saying for a while now that plants are blooming earlier than usual this year. My friend, Ralph Philbrick asked if I had the data to quantify it. I wasn’t sure if I did.

First of all, what exactly is a normal year?

I’ve only been taking data since the trails opened up after the Jesusita fire, and much of that time has been in drought. I have learned in that time. I couldn’t recognize many species at first, and I originally kept very crude data.

Even at the best (which I hope is now) I don’t necessarily have a very good idea of when anything started blooming. I simply run trails recording what I see. If something always blooms first on Romero (as Prickly Phlox tends to do), and I happen not to run Romero until long after that happens then I’ll get a distorted view of when it first started blooming.

When I look at the dates when any species started blooming first they seem to hop all over the place.


If the individual data are distorted they will probably be evened out by comparing lots of species (the error goes down with the square root of the number of species). If I miss the start of Prickly Phlox then I’ll probably see Sticky Phacelia blooming early somewhere else to make up for it. Or something.

But as time goes on I recognize more and more species. So in 2012 I would expect to see fewer species blooming simply because I knew fewer species.

So I will produce graphs showing a count for all species blooming on each given day of the year, but only species I had recognized by, say 2012. I’ll ignore anything I identified after that. I’ll also only look at native species. I’ll start with 2012 simply because my data before that were too poor (of course 2012 was the start of the drought so none of my years is representative).

I’ll graph things by rain year rather than calendar year, because plant growth (and blooms) tracks the coming of the rain. The rain year starts in Sep or Oct depending on whom you listen to (it doesn’t make much difference).

So here are some graphs. The red color shows the bloom pattern of 2015, the blue the bloom pattern of 2012, 2013, 2014 (depending on the graph), purple shows the overlap.



And in these four years it does look as if 2015 has an earlier spring. By about a month for 2012, and 2013, and by about 2 months for 2014.

I also wondered if various classes of plant types (annuals, perennials, shrubs, non-natives) had different blooming patterns from the combined total. Here I am using data from 2014 (last full year) and I’m not restricting myself to plants I had identified by 2012. But again these are all native plants — except for the non-native comparison.
The perennials seem to provide about 40~50% of all species blooming throughout the year. They track the total fairly well.

The annuals fluctuate a bit more, a little lower than would be expected in Dec/Jan, but otherwise the proportion seems about the same across the year.

The shrubs seem to complement the annuals.

The non-natives do not track with the natives. The red is the count of non-natives and the blue of natives (the blue count does NOT contain the non-natives so this is a fundamentally different comparison from the preceding ones).

Then I wondered what the percentages actually looked like:


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