In this second article on Determinants of Health (DoH), we will explore some of the interdependencies of factors affecting animal health and plant health – birds, bees, flowers, and trees. This intricate balance of variables, however, is being threatened by human activity and climate change. Even if not fully appreciated or completely understood, the impact on people, pets, and the planet is certain.
Migratory birds carry diseases as they travel, spreading these diseases to human communities and agricultural animals alike. This is a direct DoH for humans and animals, in addition to impacting food nutrition and food supply chains. Economic impacts directly affect the livelihoods of farms and farmers along the migratory path.
Human activity and climate change greatly affect the timing and pattern of this same disease pathway. The more we change the climate, the more we change the pattern of disease. Climate change alters bird migration timing and patterns, which worsens the disease process. Birds of prey, songbirds, and agricultural flocks are more susceptible to the negative effects of climate change on their eggs and offspring. This is currently a subject of great study in the wild and great economic and food supply concerns, regardless of geographic location or socioeconomic status.
According to the US Department of Agriculture’s Natural Resources Conservation Services, one-third of all bites of food in the nation are dependent upon honey bees and fellow pollinators. Most of our fruits, vegetables, and nuts are products of bee pollination and honey bees are responsible for pollinating crops worth $15 billion each year. These small creatures also provide food, either directly or indirectly, for countless wild and domesticated animals. And the ability of bees to pollinate is diminished by the use of many different types of pesticides.
Deforestation and climate change have negative impacts on the health of humans, animals, and plants. Less commonly known is that trees are the main source of nectar for bees. Loss of this food source directly affects the health of the hives and subsequently reduces the chance for recovery of the habitat through pollination. Further, the amount of fresh water needed by bees to maintain hydration and produce honey is considerable. Scarcity of that resource from climate change or pollution significantly affects the health and functionality of the hive.
Climate change alters when a flower is open, shifting the opportunity for pollination within a day and across the season. The health of a plant’s reproductive parts is a critical component of the entire food production cycle, even if the flower or fruit is not directly eaten by humans and/or food animals, such as the flower of a potato or turnip. Availability and variety of plants, as well as the nutritional quality of these food sources, also are affected by climate change and constitute two established DoHs.
Plants that animals eat are dependent on pollination. The majority of these are not pollinated by bees and other insects but by wind and weather. Most of us are aware that pollen in the wind contributes to seasonal allergies. There is less awareness, though, of the impact on airborne pollen that is needed to yield plants for consumption by grazing animals – domesticated or wild – and other livestock. Alterations in wind and weather from human activity and climate change are interfering with this form of pollination. The result is reduced plant production, depleted food sources for both humans and animals, and increased food costs.
Trees and large plants serve many important environmental functions. Healthy flora exchanges carbon dioxide, reverses climate change via sequestration, and draws water from the ground that is released at the top to produce humidification. Yet as climate change causes the atmosphere to become drier, trees are not as effective with gas exchange. With increasing temperatures and decreasing humidity, trees need to take more water from the soil in order to maintain gas exchange. These effects of climate change dehydrate soil, increase wind erosion, and disrupt the sensitive habitats under tree canopies and within the soil to the further endangerment of many species.
Additional effects of climate change are light cycle changes. The amount, frequency, and timing of sunlight reaching the earth’s surface defines the light cycle. This circular path of light and dark is dependent upon humidity, temperature, and weather. Changes in the light cycle, then, are both a factor in climate change and a result of climate change. All plants will use some oxygen at night, with larger plants and trees requiring more than smaller ones. But trees experiencing heat and humidity stress, combined with alterations in the light cycle, will consume significantly more oxygen and release significantly more carbon dioxide during the day than unstressed flora.
Humans significantly impact the health of all plants and animals, as our activities interact with every environment. In turn, the environments and all life contained therein interact with us, which underscores the need for good environmental stewardship. And mitigating the degree to which this interaction has a negative impact on the health and well-being of humans, animals, and plants is a key factor in containing healthcare and food costs and is the responsibility of us all.
Allison A. Sakara, N.P., M.S.N., R.N., P.H.R.N.
Founder & Executive Director, High Alert Institute, Inc. (a 501c3 Not-for-Profit)