14 Mar Non-native Bulbs, White Tailed Deer and Spring Ephemerals
Nonnative Bulbs
Article by Keith Moore
March 14, 2025
Nonnative Ozark Witch Hazel with bee
Have you seen any early spring flowers recently? Maybe snow drops or crocuses? Daffodils and tulips will soon be blooming too! What do all these plants have in common? They’re not native to our area! Most of them come from the Mediterranean region, with ranges from North Africa to Europe to the Middle East and beyond. Most of these nonnative plants have large bulbs that allow them to keep water and nutrients below ground during the harsh, dry months of Mediterranean summers.
Now you may be wondering, are these nonnative plants a problem? Can they become invasive? Thankfully they typically are not invasive! Most of these flowers are well behaved and don’t wildly reproduce. Occasionally they will naturalize in woodlands, but can often coexist with our native species just fine.
In fact, nonnative bulbs can sometimes be the only source of nectar and pollen for early spring pollinators! As climate change causes temperatures to fluctuate increasingly irregularly, our insects are emerging earlier and earlier in spring. This temperature imbalance causes insects to emerge long before most native plants have produced flowers.
Skunk Cabbage Flower
This is where nonnative bulbs come in! These plants can handle frosts better than most native species and therefore emerge earlier. That means when a 60 degree day hits in February and there are no native flowers around, crocuses and others can provide an emergency source of food to pollinators that are just waking up!
However it is not all doom and gloom when it comes to early spring native flowers. Trees like silver and red maples flower incredibly early compared to other native species. Skunk cabbage is a unique wetland plant that also emerges in early spring, sometimes even when snow is still on the ground! Some ephemerals like spring beauties and toothwort are not typically eaten by deer. Unfortunately some favorites like violets and trilliums are gobbled up by deer.
White Tailed Deer and Spring Ephemerals
Article by Keith Moore
March 14, 2025
Dutchman’s Breeches
Our local deer populations are having quite an impact on this plant-pollinator relationship. Did you know that by the early 1900’s, white tailed deer were nearing extinction? Similarly to the buffalo, white tailed deer were highly valued commodities and were hunted extensively. The US Biological Survey estimates that before European colonization, white tailed deer numbered around 30 million. By the early 1900’s, their population dropped by 99% to approximately 300,000.
Thankfully the federal government passed laws better regulating hunting and finally took steps towards conservation. However, around the same time gray wolves, the main predator of white tailed deer, were eliminated from our forests. That means that since the mid 1900’s, white tailed deer have been able to exponentially increase their population with few predators to limit their numbers.
Today white tailed deer have rebounded and are back to around 30 million strong. Unfortunately, the distribution of their population has drastically been altered. These animals thrive in woodland edge habitats, making our suburban expanses a paradise for them. Today deer populations are largely centered around urban and suburban areas, often declining in more rural areas. For some perspective, it’s generally said that 10 to 15 deer per square mile is a healthy population. However today in Pittsburgh, we have about 40 deer per square mile!
Trillium on Falls Ravine Trail
This overpopulation of deer has led to extreme habitat degradation in many of our green spaces. Deer often selectively eat our native species, especially important ones like spring ephemerals. These flowers pop up in early to mid spring before the trees leaf out, taking advantage of the temporary sunlight. That’s why spring ephemerals are so important to our spring pollinators. So when deer eat all of our native spring ephemerals, sometimes the crocuses and daffodils are all that will remain. While this relationship isn’t perfect, it’s nice to know that the first flowers of the year, even though not native, are still playing an important role in the ecosystem.
There are steps being taken to restore this imbalance. Across the country and even within our own Frick Park, deer exclosures have become common to protect plants from over browsing. Additionally the city of Pittsburgh has recently instituted a bowhunting program within some city parks to keep deer populations under control. As stewarding efforts continue in the park, we are making sure to select native species that deer usually won’t eat. While it’s highly unlikely wolves will ever be reintroduced to urban areas, some say coyotes are beginning to fill that ecological gap. Only time will tell how our relationship with these graceful yet destructive creatures will evolve.