The Sinister Side of an Early Spring
Although, a mild winter may seem like a positive thing – bringing forth more comfortable weather, less layering, early blooms -- the impact on the sequence of corresponding natural events is substantial, and potentially catastrophic.
During one of our weekly birdwatching outings in early January, my friends and I noticed that the Snowdrops (Galanthus spp.)were already making an appearance through the leaf litter. It struck us as pretty odd to see them this early in the year, so we looked up the blooming timetable, and it turned out that the New York City Parks Department had already mentioned on their website that the first ones were spotted blooming on January 1stin Central Park, and then in the Lower East Side less than two weeks later, though they are usually not expected until the end of January (still considered early) or in the first few weeks of February.
Snowdrops (Galanthus spp.) in Central Park in Manhattan, NY
Other early bloomers around the city this year include Japanese varieties of Cherry (Prunus spp.) trees, such as Yoshinos (Prunus × yedoensis 'Somei-yoshino') and Okames (Prunus x incamp 'Okame'), as well as other Asian tree varieties, like Star Magnolias (Magnolia stellata) and Saucer aka Tulip Magnolias (Magnolia × soulangeana), all of which were expected between the last week of March and mid-April. I noticed some of the edges of unfurling magnolia blooms becoming blackened, and I suspect that the instability of the temperature, such as fluctuations of 30°– 40°F within 24 hours, are to blame.
Magnolia (Magnolia spp.) at New York Botanical Garden in Bronx, NY
But, all of this isn’t new information. We have been on this climate trajectory for several years. In his 2017 article, Tim Radford, of the Climate News Network,explained that spring had come 22 days earlier in the United States, and 26 days ahead of schedule for Greenland. This trend has continued in subsequent years, and an analysis of 244 U.S. cities, Climate Central has determined that “the six weeks after Groundhog Day are warming up 93%.” Also, this year our Spring Equinox, the first official day of the new season, which welcomes more daylight (Equinox: aequus– latin for “equal” and nox– latin for “night”), arrived on March 19, and according to The Old Farmer’s Almanac, it’s the earliest seasonal shift in the last 124 years (since 1896).
So why is this all that bad?
What difference does three to four weeks make?
The Larger Impact on Plants
The warming temperatures in the Northeast ushered in an explosion of blooms, much to the dismay of seasonal allergy sufferers, and new growth for many introduced and invasive species. Due to this head start, several of these invaders (many of which hail from Europe and Asia) have been able to establish themselves much more quickly, able to flower and be fertilized (many by wind), as well as increased their ability to grow and spread, expanding their range before our natives have had a chance to awaken from dormancy. These species include Japanese Rose (Rosa multiflora), Wineberry (Rubus phoenicolasius), and Lesser Celandine (Ficaria verna).
But what about the native plants that may have actually cut their slumber short? One such example are our native maples. The Red Maple’s (Acer rubrum) crimson pompom-like blooms and the pendulous green flowers of the Sugar Maple (Acer saccharum), had been on display earlier than usual, with some being spotted blooming in late February in the city and upstate New York. Though a beautiful sight to behold, these flowers (that may be male, female, or both depending on the species) could be harbingers of an industry collapse to come.
At a recent “DIY Maple Sugaring” event offered by the Westchester Land Trust, Kristen O’Hara, Conservation Programs Coordinator, explained to us that as the winters have been milder, the sap carrying sugar to the aerial parts of the trees has begun flowing sooner, shifting the harvesting period from early March to as early as mid-January. Not necessarily a bad thing, right? Syrup makers could just start earlier, no? Shorter winters may actually mean the end of the road for many companies in the decades ahead. “In the last 50 years, sugar content has changed. The sugar content in a Sugar Maple used to be about 6%”, Kristen stated. Sugar Maples hold the title for the highest sugar percentage in maples, and now a decline is being noticed, with some trees having as low as 4% or even a devastating 2%.
Red Maple (Acer rubrum) at Forest Park in Queens, NY
Brief dormancy periods mean the trees refrain from producing excess sugar stores leading to less being packed away in their roots for future use come warmer weather. “So, these trees stop producing the kind of sap that we need for the industry,” Kristen continued, “They are not going to die. They are going to be fine, but their leaves will stop being red, because their sugar content is the whole reason why their leaves are red, and this will also impact tourism, and its impacting one of the biggest industries that New York and the Northeast has, which is maple sugaring.” She proceeded to test the sap that had just been collected with the refractometer (also called a saccharimeter), which measured a 3% sugar content. She said that their land was rich in healthy soil, which may be a reason that the content is higher than most trees in surrounding areas. Given the decrease of a little over half the previous content standard, we can theorize that within the next 50 years, there may be a crisis for maple syrup companies in our area, and that the industry will cease to be one able to carried out within the states, and will become exclusive to our northern neighbor.
Earlier “green-up” periods also effect our agricultural industries because earlier emergence would expose leaves and flowers to unexpected late frosts, which could, in turn, destroy their blooms, eliminating their chances of being pollinated, bearing fruits, and ultimately, no seeds, or worse, defoliate plants resulting in premature crop death.
The Impact on Animals
Warming temperatures are affecting animal species because their life cycles are dependent on their synchronization with seasonal changes and all that it brings. While we are aware of the devastation of such tragedies like the melting ice caps, we may not pay attention to the smaller changes that are not extensively covered by the media, such as how these differences of only a few degrees are impacting the lives of wildlife big and small.
During the heart of the winter, we tend to see less rodents, for example, because most species go into hibernation. As the temperatures drop, they experience their own drops in activity levels, a physiological change known as torpor. Squirrels and chipmunks undergo this shift, but this winter they appeared far more visible on the landscape than previous years. This could mean that higher amounts of pests, such as mice and rats are being more active and starting to reproduce earlier.
Meanwhile, on the opposite side of the size spectrum, bears have been reported as awakening from hibernation a month earlier than expected, or even foregoing the dormancy period all together, such as some bears in Siberia, where the temperature barely dropped below 50°F.
Millions of years of evolution have intrinsically linked the relationship between plants and insects. One example is the plant-herbivore relationship. Many plant species serve as hosts, a specific food source required for insect larvae to reach maturity, and if the timing of emergence is altered, the effects can be disastrous to their life-cycle. There have been reports of Monarchs (Danaus plexippus) migrating northward earlier, arriving to lay eggs in Kansas, Texas, and Oklahoma before their host plants, Milkweed (Asclepias spp.), have had the opportunity to establish themselves. Sandra Schwinn, a Monarch Watch Conservation Specialist, explained in an interview that the young native Milkweed sprouts are only about “3 inches tall with nine or 10 eggs. That wouldn’t even feed one [caterpillar].” These types of instances are a serious issue for specialist feeders because this would result in a lower rate of offspring survival.
Monarchs (Danaus plexippus) in Central Park in Manhattan, NY
However, early egg-laying periods may not be an issue for a generalist feeder, such as the larvae of the Gypsy Moth (Lymantria dispar), but it could spell trouble for the plant species they do choose to feed on. There is a strong plant-predatory insect relationship, such as that between several herbaceous and woody species with parasitic wasp species. These plants release volatile compounds that signal that they are being attacked and according to studies, such as one involving Black Poplar trees, these chemical cocktails are tailor-made to attract certain predators during certain times of the day. Many of these predators overwinter, but if such generalists herbivorous insects were able to begin their feeding of indiscriminate plant species earlier, those plants may be releasing volatiles to attract help to no avail, for their calls may go unanswered if the predators have not yet established themselves at that point in the season or have been decimated by unexpected late frosts.
What about the plant-pollinator relationship? While we have many generalists, there are specialized species that practice flower fidelity, and earlier blooms may spell disaster for both parties. If the flowers appear before the pollinators have transitioned out of dormancy, they may not be fertilized in time or the numbers of those that are may be greatly reduced. A decrease in fertilized flowers means a decrease in certain fruits and berries, which can impact food availability for native or migrating species. Along the same vein, less fruit means less seeds, again affecting the amount of resources available. Though there are many species that can self-fertilize (monoecious plants), dioecious plants, which have male or female flowers respectively, may have a harder time if they are dependent on insects, rather than wind, to transport pollen between them.
Temperature and humidity affect not only blooming times, but nectar and pollen production as well. The flowers themselves are food sources for thousands of insect species, and a shift in schedule can impact foraging activity and life cycle dynamics, such as output of offspring.
I actually spotted my first honey bee (Apis mellifera) and a Cabbage White butterfly (Pieris rapae) of the year, during the first week of March. They had begun to emerge and feast on the seemingly overabundant flowers. So, what could potentially go wrong? Before venturing out to enjoy the 65°F weather, I had seen the upcoming week’s forecast and saw that the temperature was due to make some sudden drops into the thirties. These fluctuations could mean death for our invertebrate friends.
European Honey bee (Apis mellifera) on a Crocus (Crocus vernus) at Central Park
At his lecture “Introduction to Beekeeping”, Nick Hoefly, beekeeper at Astor Apiaries, stated that such rapid changes could be the downfall for bee colonies that have emerged too early and ceased to form winter clusters. During the winter months, the cold slows down their metabolisms and the bees group together, with the queen safe in the center, generating heat (an average of 92°F) by vibrating their wings, enabling her to survive along with enough worker bees to forage come spring. Without the protection of this cluster, a sudden frost could kill not only their food sources, but too many workers or an even worse scenario -- the queen – sending the colony into disarray and potential collapse.
According to Nick, the honey bees that we have come to know and love, and that have become an integral part of our agricultural industry, were originally brought here from Europe during the 1600’s, and are considered an “beneficial invasive species that doesn’t negatively impact the environment”. A shift in the seasonal transition may lead to dearth, a term defined as “a drought of flowers” when used within the beekeeping community. This lack of food could promote die off in the colony, and even incite behavior such as robbing between hives which could increase the aggression and stress levels of your colony. When asked about his thoughts on how the early spring will affect the upcoming beekeeping season, Nick responded, “This is going to be an interesting year, just because of the early bloom”. He noted that he, along with other hobbyists’ he has communicated with thus far, are half expecting a week of freezing sometime later in March, that would possibly kill their bees. In reference to what the impact may be on honey production, he continued by saying that “if all the blooms have happened, then in the summer we might have an extended dearth and have to put on emergency syrup or some sort of emergency food source for bees. But you would just have to observe, manage it, and monitor it as you go.”
What about our feathered comrades, especially those that have begun their long and treacherous spring migrations? On their website, Audubon details that in Queens County, NY alone, we are facing a 3°C increase and that we have 63 stable bird species, along with highly vulnerable species including the Eastern Towhee (Pipilo erythrophthalmus)and Piping Plovers (Charadrius melodus), along with those considered moderately vulnerable, like the American Woodcock (Scolopax minor) and Willow Flycatcher (Empidonax traillii), and species of low vulnerability as well, such as the Bald Eagle (Haliaeetus leucocephalus) and the Wood Duck (Aix sponsa). Warming weather will contribute to habitat loss forcing species far from their original breeding grounds and into ecosystems with new competition and will become likely prey to predators in those areas, which can send a population into freefall. Human-driven habit loss and the use of pesticides are already an active threat to avian decline, and these drops will effect humans in a myriad of ways, including higher rates of disease due to less carrion consumers, higher rodent population damaging crops without raptors to keep them in check, and even the further fall of forests, such as rainforests in which many trees depend on birds for seed dispersal.
Eastern Towhee (Pipilo erythrophthalmus) at Central Park; Courtesy of Carol Seffari
During the Audubon New York and Audubon Connecticut joint-webinar, “Spring Bird Migration: The Magical Mystery Tour”, available for replay here, Ken Elkins, Community Conservation Manager (Audubon CT), detailed the effects a milder winter may have on our traveling feathered friends. “The short distance migrants that are coming in February through early April -- their times are probably adjusted more because of weather patterns that they are triggered by temperatures and winds a bit more. The long-distance migrants, the neotropical migrants that are in Central and South America, they’re just preparing now based on day-length to start their migration and if they have the right winds, then they might be able to make that migration a couple of days sooner.” As an example, Ken brought up a bird mentioned earlier in the broadcast, the Grey-cheeked Thrush (Catharus minimus), that was recorded traveling from Columbia to Ontario, Canada in 47 hours when in previous years that route may have taken the same bird 96 to 120 hours. He stressed the point that “overall those birds are still migrating at the same times because it isn’t the exact temperature of weather that is triggering them to start their movement” but rather the increase in daylight.
Corrie Folsom-O’Keefe, Director of Science (Audubon CT) added that while temperatures and winds may cause an impact to the rate of migration, an important issue to note is the accessibility of resources along the route. “Take the Red Knot, for example, if they come from South America and land on the shores of the Chesapeake and Delaware Bays, but [the] horseshoe crabs haven’t started spawning yet, then they are going to have to wait for those resources to be available before they can continue their migration.”
As temperatures around the globe rise, there have also been studies on the decreasing sizeof many bird species. The decline in overall body mass is believed to benefit a bird’s ability to thermoregulate, which may make them more resilient when faced with hotter climates. An interesting studyon incubation calls and their effect on a chick’s growth before they hatch, proposes that these songs may be their only hope for survival in this shifting world. Kate Buchanan, a Deakin University Associate Professor, explained the process in an interview with Smithsonian Magazine, referring to the calls as an “acoustic signal” that is “potentially being used to program the development of offspring”, serving as a warning as to what to expect. The researchers conducted controlled experiments in which Zebra Finch (Taeniopygia guttata) eggs were either left with their parents, or removed early and therefore deprived of hearing their parent’s incubation calls, which occur only in the late stages of incubation. “Hearing that call before you even hatch affects your development, affects your growth rate, probably affects your vocalization and it affects your behavior and choice 100 or 200 days later when you go to nest yourself”, continued Buchanan, adding that those exposed to the calls would later go on to successfully nest in areas that were warmer than normal versus their deprived counterparts.
Changes in ocean temperature, decrease of pH, and species abundance are disrupting the food web and life cycles of countless marine creatures.Our oceans have experienced an increase in temperature“by over 1°C”, according to evolutionary ecology professor Martin Genner of the University of Bristol in Britain. Not only has there been significant coral die-off (also known as coral bleaching), but many fish species are also unable to survive in the warmer waters and are making their way away from their native ranges to cooler waters towards the poles that have now become more hospitable. In a studythat involved reviewing extensive data collected over the last century, Professor Genner and his colleagues were able to identify substantial changes of population densities, and fellow study authorLouise Rutterford, explained that they “predicted that warming seas would lead each species to increase in abundance at the pole-ward side of its range, as the warmer climate made the habitat more agreeable. We also predicted that each species would decline in abundance at the equator-ward side of its range, as temperatures become too warm to survive…Some marine life suffers as it is not able to adapt fast enough to survive warming, and this is most noticeable in populations nearer the equator…This is concerning as both increasing and decreasing abundances may have harmful knock-on effects for the wider ecosystem."
Another issue is that of ocean acidification, which has been affecting crustaceans and mollusks, including our native New York oysters. The acidity of the water impedes shell formation, so many young oysters are not surviving long enough to mature and spawn. Our local populations are already struggling with the effects of pollution, and are an important species to protect thanks to the ability of oyster reefs to work as storm breaks and losing them means more coastal erosion and more damage during hurricanes. Oyster farmers have also been affected, experiencing massive die-offs, but some have started to experimentwith using carbonates as buffers in their water supply to increase alkalinity and help their oyster stands survive.
Eastern Oyster (Crassostrea virginica) at Orchard Beach, Bronx, NY
These temporal shifts are causing major disruptions in processes that nature has fine-tuned over millennia, and the relationships between all organisms, including humans, are under threat. There needs to be a shift, instead, in policy-making, conservation and reforestation efforts, waste management, and consumerist ideology – all of which are enormous feats, but many efforts are currently ongoing. Then, there is the possibility that even if we take all of the appropriate action, it may be too late to make a substantial difference.
It is ironic that this year, upon witnessing many of these changes firsthand, and learning about the systems at work and how each can get affected, like a row of dominos collapsing upon the other, the arrival of spring has been a bittersweet one. Climate change is continuing to set off a chain of events that so many living beings will fail to recover from. Spring is supposed to be symbol of rebirth and new life, but for me, it’s lost some of its magic.