El Niño: Winners and Losers


El Niño has been a welcome arrival for drought-stricken California, but it's proving to be a two-sided coin for local flora and fauna.

by Christian Yungert

Jan. 29, 2016—The dry times would appear to be ending as El Niño, our hydro-savior, has come to shower us in its life-replenishing rains. The dried ground gratefully gulps rainwater as fast as it falls. The brown tints that have long shaded the typically verdant fields and forests are retreating in the face of fresh new growth. The San Lorenzo River, reduced to a trickle in places, has burst to life as it rushes to return wayward raindrops to their ocean home.

Commonly mistaken as only increased storms and rainfall, El Niño is a change in Pacific Ocean currents with global impacts. In El Niño years, the Trade Winds that normally push warm water west across the Pacific Ocean fail. As a result, the cold-water currents and nutrient upwelling that fuel the biodiversity of the Monterey Bay and the Eastern Pacific Ocean are halted as warmer temperatures from the Central Pacific Ocean spread eastward.

These changes surge through local ecosystems and food webs. Organisms at the bottom of the food chain, like plants and plankton, experience profound effects on their population health. These changes in turn influence the populations of increasingly larger organisms. Biologists refer to this phenomenon as a trophic cascade. To some it is a blessing, and others a curse.

The Losers: The Ocean Food Web

Plankton El Niño stops coastal upwelling. When this happens, all the nutrients that have fallen to the bottom of the ocean remain in Davey Jones’ Locker, not to be pushed to the surface by cold-water currents as in normal years. The warm water and lack of nutrients cause plankton levels to plummet. The main buffet in town has suddenly run out of food.

Baitfish An integral part of the Monterey Bay ecosystem, the Northern Anchovy and Pacific Sardine have long supported fisherman and marine life alike. However, without plankton to feast on, these swimming snacks struggle to find a meal. Their limited ability to migrate to cooler waters often spells death.

Seals and Sea Lions These Monterey Bay favorites are in for a tough time. Warm waters drive the food sources for harbor seals and California sea lions deeper and further from their normal range. Already managing a tight energy budget, local pinnipeds are having to work even harder for their usual meal. The results are ugly. Less food for mom equals less food for baby. El Niño is notoriously responsible for the malnutrition and death of many young seals and sea lions.

Sea Otters Our local kelp forests thrive because of cold water and resource rich upwelling. El Niño’s effects and rough storms trash these fragile ecosystems. As a result, Monterey Bay’s iconic sea otters lose both supermarket and sanctuary.

Seabirds Prey that decides to live in deeper water might be a manageable problem if you live in the ocean. But, for local seabirds that can only dive so deep, their meals are just out of reach. Large birds like the California Brown Pelican will migrate to better feeding grounds. Others like our Common Murre already dot local beaches, having starved.

El Niño Winners: Plants and Land Animals

Annuals These are the plants that flower, go to seed, and then die all in one year. Many sit patiently in the seed bank until the right conditions sprout them into life. Colorful local natives like Purple Owls Clover and Baby Blue Eyes could be plentiful this spring.

Perennials Our long-term residents are starting to thrive. The big increase in water and soil saturation will lead to increased growth, flowering, and fruit production. Be on the look out for Trilliums and Fetid Adder’s Tongue; they should be doing well.

Rodents and Small Mammals The little guys who make their living off seeds and plants are set to enjoy some good times. Seed irruptions have been know to cause small rodent populations to boom to 20 times their normal level. Our woodland neighbors like the California Mouse, Dusky-Footed Wood Rat, and the Western Brush Rabbit are in for a treat.

Carnivores Coyotes, Grey Foxes, Bobcats, and others are licking their chops. The upcoming population boom of small mammals will make meals easier to come by. Keep your eyes peeled for an increase in potential sightings. Well-fed mothers have an easier time raising their young and healthy young mean more adults. You just might catch a glimpse of one of our more elusive neighbors.

Other Victims and Beneficiaries of El Niño

Losers: People with Allergies It doesn’t take a genius to know the increased rain has been good to the plants. But, with the soil becoming saturated, expect plant growth to kick-start. Not only will plants be adding new growth, but they’ll be making pollen like crazy. People who suffer allergies should prepare for a tough summer. Locust Trees, plentiful around Santa Cruz County, with their drooping yellow bouquets of flowers, will be especially guilty.

Losers: Drought-Damaged Trees Those hit hardest by the drought may fall by the wayside. Weakened root systems limit a tree’s stability. Combined with softer, water-soaked soils and strong winds, these trees don’t have what it takes to stay standing. Recent observations from the UC Santa Cruz Forest Ecology Research Plot have noted an increased number of native Madrone trees toppling over. Other young trees of all species that never had the chance to establish strong roots will be victims as well.

Losers: Home Gardens In wet El Niño years, herbivorous insects are known to increase. This could spell trouble for local gardeners. Expect increased numbers of garden pests from thrips and aphids to snails and slugs.

Winners: Non-Native Plants Ill adapted to the cycle of drought that occurs in California, non-native species had it rough the past few years. With life-giving water flowing once again, expect them to rebound with a vengeance. Invigoration of a presumably strong seed bank ensures that these invaders aren’t going to be defeated anytime soon.