Insects
Wetlands ‘right-now’ – what’s happening?
Although International Wetlands Day happens on 2nd February each year, this is the time of year when wetlands, in the northern hemisphere, are almost dormant. If you go to visit a wetland on 2st February, you won’t see much happening.
Many of the plants and animals that normally live in the wetland are going through their winter dormancy now.
In February you will see the bare stems of the reeds and lots of dead vegetation. Under the surface however lots of things are already happening. Many of the animals that live in the mud on the floor of the wetlands are already preparing for spring. The larvae of the dragon flies are already actively feeding on other small animals in the detritus at the bottom of the pond. These larvae are fierce predators and this video link shows you how they behave on the bottom of the wetlands at this time of year if they can find prey dragonfly larvae feeding (see below).
When the risk of severe frost has passed, some of the plants will begin to emerge…..
….and when the weather warms up a bit and the average daily temperature stays above 6 degrees or so, the first obvious signs of life will appear.
In fact, it is at the wetlands that you can first see the stirrings of the new spring. The green shoots will appear on the reeds first of all. Then other smaller plants like the bog bean and the mayflower will begin to push up their foliage.
Then you know for sure that the winter is over!
Zooplankton
Under the surface of the water in the small freshwater wetlands there is an unbelievable diversity of life. There are hundreds and sometimes thousands of different species of animals and plants to be found there. Among the types of animals there, you can find insects, molluscs, worms, crustaceans, beetles and even fish – like sticklebacks, and tiny floating animals called zooplankton. Some of these animals like to live in the water column, some like to crawl about on the stems of the plants growing out of the bottom of the wetland and some others like to live their lives in the muddy substrate on the floor of the wetland.
There are many weird animals living in the wetlands, especially where there is standing water for most parts of the year. The common water flea, Daphnia pulex is a prolific inhabitant of our wetlands and lakes and its population explodes in May and June as they take advantage of warmer temperatures and the easier availability of food such as plankton and bits of organic matter floating in the water. However, and unfortunately for the poor old Daphnia, when their numbers increase sharply, other higher animals that like to eat daphnia (like carnivorous larvae, small fish, newts and small frogs) also increase in number and they keep the numbers of Daphnia in check.
Dragonflies and Damselflies
The Red Darter, common in the Irish wetlands in July & August
Because we’re now in late Spring and early summer is not far off, we want to bring you some seasonal information about the Dragonflies and Damselflies. The very cold spring is likely to have delayed the emergence of the dragonflies and damselflies somewhat in 2021. Many of the, thirty or so, species that we expect to see in Ireland come up on the wing in July and August, so there is still time for you to get out there and see some during this summer season.
If you want to see pictures of the different types of dragonflies that are found in Ireland, as well as information on which months they are on the wing, take a look at this link.
Ostracods
Under the surface of the water in the small freshwater wetlands there is an unbelievable diversity of life. There are hundreds and sometimes thousands of different species of animals and plants to be found there. Among the types of animals there, you can find insects, molluscs, worms, crustaceans, beetles and even fish – like sticklebacks, and tiny floating animals called zooplankton. Some of these animals like to live in the water column, some like to crawl about on the stems of the plants growing out of the bottom of the wetland and some others like to live their lives in the muddy substrate on the floor of the wetland.
There are about 8,000 species of ostracods living on earth today. There is evidence in the fossil record that ostracods were prolific on earth almost 600 million years ago and they are still thriving today. About 20 species can be found in our freshwater wetlands. Ostracods are weirder than fiction (picture opposite) and the species found in Ireland range in size from about 0.1 mm to about 5 mm in length. As crustaceans, they rely on a bi-valve shell of hard material to protect their delicate inner organs. They can slam the shells shut to protect themselves, if threatened.