Ongoing Environmental Issues


Regional issues

The Hudson Valley is a unique bioregion that is faced with pressing environmental issues such as climate change, habitat loss and fragmentation, invasive species, and deer overabundance. These issues are often interconnected such that one may occur or worsen because of the presence of another. Ecosystems, biodiversity, our economy and health and safety are all threatened because of these ongoing environmental problems.

Climate change

Catskill Mountains in autumn.

The Earth's climate is changing. This is primarily because greenhouse gases (or gases that trap heat in the atmosphere and stabilize earth's temperatures) are more abundant in our atmosphere now than they were before the Industrial Revolution. While greenhouse gases such as carbon dioxide, methane and water vapor naturally occur in the atmosphere, human activities (e.g., fossil fuel combustion, agriculture) have resulted in their dramatic increase. It is our contribution of these gases that is causing the climate to change at a rate never experienced before. Impacts of this change across the planet include:
  • Rise in average annual temperatures
  • More frequent extreme weather events (storms, droughts, rainfall)
  • Melting glaciers, sea ice, ice sheets, and permafrost
  • Sea level rise
  • Ocean warming and acidification
  • Extinction risk to numerous species
  • Threat to agriculture and crops
  • Appearance of warm-climate diseases in historically cooler climates

In the Hudson Valley we are faced with warmer winters, earlier springs and decreased snow cover that can threaten biodiversity, crops and the maple syrup industry. Record temperatures are being experienced more frequently throughout the year and more intense storms and precipitation events are leading to flooding that cause erosion, damage infrastructure and re-route streams or rivers. These factors will continue to accelerate in the future without mitigation to lessen human impact across the planet.

Habitat Loss and fragmentation

Example of habitat fragmentation in a dominant forested landscape. Image provided by

Habitat loss and fragmentation (the reduction of a habitat's size by breaking it into smaller pieces) is commonplace around the world. Humans impact habitats directly by clearing land for road-building, agriculture, and residential or commercial development. Habitat loss and fragmentation is the most prevalent threat to the ecosystems of the Hudson Valley. Some consequences of habitat loss and fragmentation include:
  • Reduction in biodiversity and threats to rare species
  • Altered distribution of species, migration routes and population sizes
  • Introduction of invasive species and nuisance animals

Invasive species

Eastern hemlock (Tsuga canadensis) twig covered in the hemlock wooly adelgid (Adelges tsugae), an invasive insect pest.

Invasive species are plants, animals, fungi or other organisms that are not native to a country, region or ecosystem and whose introduction causes or may cause harm to the environment, economy or human health. Invasive species can spread unchecked, taking resources (space, sunlight, nutrients, water) away from or killing native species. They pose a threat to biological diversity, alter community structure and can change ecosystem processes. Some characteristics that cause a species to become invasive include the following:
  • Absence of natural predators and diseases
  • Rapid growth and reproduction
  • Tolerance for wide range of environmental conditions
  • Ability to live on various food sources
  • High dispersal ability

Invasive species can be introduced to ecosystems through a variety of pathways. These include:
  • Transport on vehicles
  • Ballast water in ships
  • Exotic pet trade
  • Transport of firewood, or other natural materials
  • Plants and seeds imported for horticulture and legally sold in some stores (varies by state and species)
  • Dispersal by birds, deer, rodents, humans, other animals, wind, water

After establishment, invasive species can further spread through dispersal by wind, water, roots, humans or animals. In the Hudson Valley, land development, fragmentation, pollution, overabundant deer and climate change are all factors that can favor the spread and growth of invasive plants and animals.

Deer overabundance

White-tailed deer fawn in a forest understory dominated by Japanese stiltgrass (Microstegium vimineum).

White-tailed deer (Odocoileus virginianus) are an important component to our forests. However, their population size across much of the Hudson Valley has reached unsustainably high numbers over the last few decades due to lack of predators and increased habitat fragmentation from human development. Overabundant deer populations are known to degrade forest ecosystems, inflict economic hardships, and pose hazards to human health and safety. Below are some of the documented impacts of deer in the Hudson Valley and across much of the country. Overabundant deer:
  • Inhibit forest regeneration by eating tree seedlings
  • Transport invasive plant seeds to new areas via their fur or hooves or via ingestion
  • Decrease native understory plant diversity and density
  • Reduce ground-nesting and understory bird populations through frequent disturbance and reduction of plant density
  • Damage crops, gardens and landscape plants
  • Cause deer-vehicle collisions

A healthy deer population is one that is 10 deer or less per square mile. In the more fragmented areas of our region, deer populations are estimated to reach densities over 70 deer/sq. mile. The larger the population becomes, the more damage that is inflicted to our native ecology and our economy. Deer management activities coordinated on a regional basis will be necessary to help reduce the deer population and their impacts.

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