Why would pink flowers not grow on the right side of a field when the blue flowers are all over. Hypothesis?

I need to come up with a scientifice hypothesis and experiment. On a scenic drive I noticed that there are pink flowers growing on the left side of field while blue flowers were all over. I noticed a small group of trees in the middle of the field with deer sleeping under them.

Why would pink flowers not grow on the right side of a field when the blue flowers are all over. Hypothesis?
There are a few that you could use:





1. Pink flowers were introduced recently, and blue flowers have been around for a long time. The blue flowers have had enough time to spread seeds across the entire area, but the pink flowers are still trying to spread.





2. The pink flowers have different nutrient requirements than the blue flowers, and only that part of the field provides it for them. Maybe whatever is on the edge of the field (a river? a road? more trees?) is providing slightly different nutrient balances, like increased shading, or more nitrogen content in the soil. It could also be that something present in most of the field (maybe a byproduct of deer poop, or a toxic contaminant) is less in that side of the field, and pink flowers are more susceptible to death by that toxin than blue flowers.





3. The animals in the area (like the deer) prefer to eat the pink flowers over the blue flowers, so the pink flowers around the copse of trees have all been eaten, and only that small patch remains.





4. The animals in the area (like the deer) prefer to eat the blue flowers over the pink flowers, which spreads the seeds more quickly.





5. Blue flower seeds can pass safely through the deer's gut and thus get spread across the entire field, but pink flowers get damaged while passing through the deer.





6. Blue flowers out-compete the pink flowers, so that pink flowers die wherever blue flowers are growing. Their root systems might prevent the pink root systems from growing deep enough to sustain themselves, or they may absorb all of the nutrients that pink needs first.





Note that 3 and 4 are exact opposites of each other, but could create the same result on different time scales and in slightly different situations. For example, if both were introduced at the same time, and deers preferred blue flowers but don't eat many of them, #4 makes sense. On the other hand, if deers absolutely love pink flowers and eat them all of the time, it could explain why you don't see many, even though they were, at one point, growing across the entire field. That explains #3.





Also, this may not just be about deer. There is an entire ecosystem present in the field and the surrounding area. A different animal could be eating the flowers and causing this imbalance of flower color.
Reply:Maybe the seeds for the pink flowers were only spread on the


one side of the field and the seeds of the blue flowers were


spread everywhere. Also maybe the pink flowers need


more morning sunlight then the blue flowers.
Reply:something the deer are doing is changing the viability of certain strains of the same plant. this is possibly to do with


a) the deer walking on one side of the field might expose some buried seeds which out compete the others.


b) the seeds passing through the deer's gut might kill pink or blue seeds or help one type germinate faster than the other


c) the urine or faeces of the deer might help or hinder one type of flower