The intersection of wildlife and climate change – Trentonian
New Jersey has always been a busy intersection – and not just where major freeways intersect!
This state we find ourselves in is also a major intersection for wild things! New Jersey is the northern tip of the geographic range of many “southern” species and the southern tip of many “northern” species. Mountain ranges overlap here, making this small, highly urbanized state a “sweet spot” with an astonishing diversity of flora and fauna.
But as Earth’s temperature warms due to climate change, ranges are changing, and adaptable species that can move easily are moving north, especially insects and fungi.
This comes at a time of global biodiversity loss. According to the World Wide Fund for Nature, there has been an average global decline of 68% in the populations of mammals, birds, fish, reptiles and amphibians since 1970. In North America, the decline was 33 % – less severe but still alarming.
Most biodiversity loss over the past 50 years has been caused by habitat destruction and degradation, as the human population has tripled and the human footprint on the landscape has exploded. Over the next few decades, global warming of the Earth will be a major driver of biodiversity loss.
What changes might New Jerseyans see?
Birds – If you’re a birder, you probably know that New Jersey is home to two species of chickadees, the northern black-capped chickadee and the Carolina chickadee, two common backyard birds. For years the boundary between them ran roughly between Trenton and Perth Amboy. Due to warming, the line is moving north toward Interstate 78.
Climate change is also affecting rare, lesser-known birds that live deep in forests. Sensitive migrants like golden-winged warblers, Nashville warblers, and Canada warblers are summer residents of the hardwood forests of northern New Jersey, but their numbers are declining here as populations move north. Wetland marsh species will be seriously threatened as marshes will be lost due to sea level rise.
Fish – If you fish in the ocean off the coast of New Jersey, you may have noticed changes in fish and shellfish. Lobster, surf clams and hake (also known as whiting) were once plentiful but are now becoming scarce as they cannot tolerate warmer waters. Most of the populations of all three species have moved north to the New England coast. At the same time, black bass and summer flounder (also known as fluke), once centered off the coast of Virginia, have moved north and are more abundant than ever in New Jersey. .
Reptiles – Diurnal terrestrial reptiles like rattlesnakes and box turtles are already affected by climate change. Field biologists find that unusually warm winter periods prompt reptiles to leave their underground winter lairs. When temperatures drop again, those who have ventured too far risk freezing if they cannot return. Reptiles are unlikely to use migratory corridors to adjust their geographic ranges. The biggest obstacle is the paved roads, which are often deadly traps for creatures.
Amphibians – One amphibian moving north is the green tree frog, a southern species that recently colonized New Jersey’s south side of the Delaware River.
But some who were already there may struggle. Rare amphibians like blue-spotted, long-tailed, tiger, and Jefferson salamanders that breed in pools and vernal springs will likely be affected by climate change. If we regularly see an early onslaught of summer heat, the pools dry out quickly as the trees come out. If successive broods of larvae cannot metamorphose into adults before their pools evaporate, some species may become locally extinct.
Insects – Surveys show that dozens – possibly hundreds – of southern insects that were rare or previously not found in New Jersey have become common. Many are beneficial, such as pollinating butterflies, but a few can increase stress on forest ecosystems, such as the southern pine beetle which has caused significant damage.
Common Mammals – Many New Jerseyans won’t notice the impacts of climate change on wildlife, as many of our most visible mammals – including white-tailed deer, foxes, squirrels, raccoons and coyotes – easily adapt to living around people and can thrive in any habitat.
Currently, overabundant deer are the biggest threat to New Jersey’s forests and biodiversity. They gobble up native plants, shrubs and young trees, literally clearing the way for invasive and non-native plants to thrive. Exotic plants are not preferred by deer, nor do they support the native insects needed to support a diverse bird population.
Plants – Some 850 native plant species are already threatened. Few will be able to persist as climate change adds to existing stressors. Our natural landscape is filling with adaptable weed species, just as chain restaurants and box stores are homogenizing the American landscape.
Yet, because of New Jersey’s incredible investments in land preservation over the past 60 years, this state still has a chance to retain its biodiversity and sense of place. Through the efforts of the state Green Acres program, federal land preservation programs, local governments, nonprofit land trusts, and important laws such as the state wetland laws, Pinelands and the Highlands, approximately one-third of New Jersey’s landmass is preserved.
In his book, Half-Earth, the recently deceased biologist EO Wilson called for devoting half of the Earth’s surface to nature to avoid mass extinction of species. This target seems even more cautious in light of the additional threats posed by climate change.
So, despite New Jersey’s national success in land preservation, our work is not done! Time is running out for our mission to leave many open spaces filled with diverse plant and animal species for our children and grandchildren.
To learn more about the Half-Earth initiative, visit www.half-earthproject.org. And for more information about preserving New Jersey’s lands and natural resources, visit www.njconservation.org or contact me at [email protected]
Tom Gilbert is co-executive director of the New Jersey Conservation Foundation.