How can we know exactly when and where a seed will germinate? The simple answer is we can't. Much to the chagrin of anyone who has ever tried to grow plants from seed, there seems to be an endless amount of obstacles between deposition of seed and whether or not it will germinate. At the end of the day, it seems that the land will decide where a plant is going to grow. Because of this, the seed to seedling stage of a plants life is the first and greatest bottleneck in the patterns we see in plant communities around the world.
For some plants its easy. If seed makes it to a location, the plants will grow. For many (and I mean many) plant species, habitat means everything. Anyone interested in growing plants must never overlook microclimates. We all know what climate means. At least we should. Just like entire regions can have their own climates, so too can different parts of the landscape. It could be that snow melt happens slower in one area, making the ground slightly more saturated. Perhaps there is a layer of clay underneath helping to hold water longer. If you are a high desert or alpine species, perhaps a small rock or boulder provides just enough protection from violent winds. It could even be a clump of moss or a shrubs that shelters a seedling long enough for it to establish itself. Heck, it could just as easily be a rusted out old can in the middle of the Mojave Desert.
The are limitless variations on the theme but they are all too often overlooked. There are few ways of predicting what will work and what won't. On more than one occasion I have forgotten about seeds planted years ago only to have the plants suddenly appear out of nowhere. As with everything in nature, these things are dynamic. What ecology is in need of are more studies that investigate the recruitment limitations of individual or groups of species. We need ecologists speaking with restoration practitioners and vice versa. We need to keep in mind that organisms can inform theory and then some.
Photo Credit: Zachary Cava (https://www.flickr.com/photos/101789078@N06/)