City wetlands, do they create a mosquito problem?

Stormwater treatment wetlands are becoming more and more common elements in urban areas. But does this mean we will soon have thousands of annoying mosquitos as our neighbors? Not necessarily.

Mosquito larvae occupy seasonal forest ponds, where predation pressure is weak. © Sari Holopainen

Mosquito larvae occupy seasonal forest ponds, where predation pressure is weak. © Sari Holopainen

Mosquitos can be a real nuisance around their emerging environment. While more stormwaters are treated by city wetlands, there is serious concern about a growing mosquito problem. They are not only a nuisance, but can also spread diseases.

Several studies have been conducted to control mosquitos in urban wetland areas. Certain methods are apparently capable of limiting mosquito breeding in stormwater facilities, but overall results remain controversial.

What do mosquitos need to occur? Firstly, mosquito larvae need standing water to evolve. Secondly, because larvae are especially desirable prey for fish, mosquitos succeed better in shallow waters without fish. Stormwater management planning should therefore avoid small seasonal standing water patches. Deep ponds without vegetation support fish populations, and are therefore recommended for stormwater wetlands. If shallow ponds are utilized, they should have flowing water and combined to deeper patches.

A dragonfly on its territory in a stromwater wetland. © Sari Holopainen

A dragonfly on its territory in a stromwater wetland. © Sari Holopainen

The effect of vegetation is complex. As already said, fish predate in areas without vegetation. Mosquitos also reproduce well in dense monocultures such as cattail stands. However, another research studying the effect of vegetation in water tanks found that vegetated water tanks had higher invertebrate species diversity. Non-vegetated tanks had low diversity, but maintained high numbers of mosquito larvae.

It seems that successful mosquito control in wetlands relies on species diversity. A diverse food web will produce competition and predation. Thus the creation of breeding habitats for amphibians, fish, and dragonflies controls mosquito production. In laboratory tests water bugs and odonate larvae consumed more mosquito larvae than other tested prey items. Planting herbaceous plant species will tempt dragonflies to the spot. Amphibians breed in shallow waters with vegetation to attach their spawn to. They may be highly successful in areas that are too shallow and vegetated for fish. Amphibians are actually more successful in fishless ponds, with less fish predation and competition. Mosquitos are food for several other species too, and for example measures supporting bird and bat communities around wetlands may help reduce mosquito levels.

Bird families consumes huge numbers of mosquitos during their breeding seasons. A tit couple eats over ten kilograms of mosquitos yearly. This robin nested near an invertebrate rich beaver pond. © Sari Holopainen

Bird families consumes huge numbers of mosquitos during their breeding seasons. A tit couple eats over ten kilograms of mosquitos yearly. This robin nested near an invertebrate rich beaver pond. © Sari Holopainen

Several studies have concluded that well-designed constructed wetlands in urban areas do not create mosquito problems. Wetlands should not be opposed due to mosquitos, but citizens should demand that wetlands are planned to incorporate healthy ecosystems.

Read more:

Mosquito control for stormwater faciilities

Water Resources Management and Water Quality Protection


A 21st century researcher in Slush

I’m waiting for my turn backstage. It will begin in 30 seconds. The assistant counts down 4, 3, 2, 1 Now. I step on stage. I know that I’ll have exactly three minutes to present my research to the hundreds of people attending Slush. Lights dazzle my eyes, and I begin my pitch on conserving the world’s wetlands. After three minutes my microphone will be switched off. Someone might wonder why a biologist is attending Slush: an event for start-ups, investors and policymakers.

At the first Slush Science Pitching Competition in 2015.

At the first Slush Science Pitching Competition in 2015.

We all probably have a stereotypical image of a researcher/scientist in our heads. For most of us a researcher may be a senior male in a dusty room filled with books, papers and research materials. This image is not so far from the truth, because only 10% of the 300 most famous scientist of all time are women, and most of them have been influential only during recent decades.
But we are living in the 21st century. It is time to shake the dust away from these old assumptions and build an image of the 21st century scientist/researcher. Scientist nowadays face new challenges in their work. Our societies are changing and becoming more effective, and research must concurrently follow the same path.

Universities and financing have transformed in recent years in Finland, which has created not only challenges and reforms, but hopefully new opportunities as well. The Finnish government has cut down on the funding allocated for universities, so researchers are forced to find new ways of funding our principle purpose: research. Without research we don’t develop new innovation, and in addition, we can’t fulfill a basic human need: the thirst for knowledge.

This thirst for knowledge is probably stronger in researchers than humans in general, and possibly the reason why we have chosen our profession. We researchers must still remember that many of us get our salary from public funding. Our jobs allow us to do what we love, not only for ourselves but also for the common good, and because of this it is our duty to communicate and report the results we get, instead of leaving them to just gather dust on our desks. Our principle purpose is to create new information, from which new innovation and development come into the world. But increasing information aka research is just a part of our job. We also need to assure that this new information is reachable by everyone. Last spring I heard a disturbing idea: “What if we already have solutions for every single problem in the world, but they are just in the form of dusty reports on researchers’ desks.”

As 21st century researchers we have to fight against this thought, and if anything strive to communicate our result in channels as versatile as possible. This is why I as a biologist took part in the first ever Slush Science Pitching Competition. I saw the event as a possibility of increasing the awareness of companies, investors and policymakers of our existence. Researchers shouldn’t be intimidated of presenting in different and versatile occasions, but should rather see them as opportunities to touch, anneal our amazing work, and deliver information to everyone.

Protecting one of the largest economies in the world

Wetland  ecology group_University of Helsinki_shallow waters of the Baltic Sea

Shallow waters of the Baltic Sea © Stella Thompson

Implementing the Red List of Ecosystems (RLE) has kicked off to a good start. I introduced this fairly new conservation method in a previous blogpost ( So far trial studies have been conducted in cooperation with IUCN on all continents apart from Africa and Antarctica. Several countries (e.g. El Salvador, Costa Rica, Marocco, Senegal) have additionally completed or nearly completed drafts for the RLE assessment of their ecosystems. Norway, Finland, and Australia are furthest in the task of implementing RLE categories and criteria into their national nature conservation standards and biodiversity legislation. A quick look at the different ecosystems encompassed so far reveals that various mires, wetlands, shore environments, coral reefs, and temperate and boreal forests are fairly well represented.

The Southern Hemisphere in particular has stepped up in the concrete utilization of RLE in assessing the health and collapse risk of ecosystems. Through a series of 13 studies, Australian researchers have determined that RLE is a functional tool for classifying and assessing various ecosystems. This has concurrently revealed several practical measures for promoting ecosystem conservation. Within the next couple of years the assessments will be extended to include all ecosystems in Australia. Factors most strongly weakening the health of Australian ecosystems have been gathered together. It is hardly surprising that climate change plays a large part, impairing ecosystems from rainforests to oceans and deserts to dry meadows. However, each ecosystem faces unique challenges at its own pace. This supports the all-round utilization of RLE. We cannot kid ourselves that conserving a few currently unwell ecosystems would be sufficient, but we must also take into consideration the probable changes that will occur in presently healthy or nearly healthy ecosystems in the near future. The future viewpoint should unquestionably be included in national RLE assessments.

A concurrent armament race seems to be ongoing concerning marine conservation; during 2015 at least four countries announced plans of founding the largest marine conservation areas in the world. The Kermadec nature reserve in the Pacific waters of New Zealand will span 240 000 mi2 (620 000 km2), while Great Britain is planning three protection zones in the Pacific and Atlantic Oceans with a combined area of 695 000 mi2 (1 8000 000 km2). Palau ratified the establishment of a 193 000 mi2 (500 00 km2) nature reserve, and Chile declared intentions of founding a marine sanctuary in the waters of Easter Island, covering 243 200 mi2 (630 000 km2). Complete RLE assessments should be conducted on each of these soon-to-be-founded zones, to find the areas that would most benefit from improvement. Assessments have indeed been planned for some of the reserves.

Marine conservation is geared towards securing important growth, spawning, reproductive, and feeding areas. Protecting specific ecosystems, e.g. underwater volcano chains, and securing fishing possibilities are also paramount. A recent WWF report (downloadable at calculates the combined economic value of oceans at $24 trillion. The products and services attainable from oceans is valued at $2.5 trillion. If they were an independent nation, the world’s oceans would be the seventh largest economy on the globe, ranking between Great Britain and Brazil. However, the WWF report concludes that the biodiversity of oceans has decreased by nearly 40% during 1970–2010 due to climate change, seawater acidification, and overfishing. Currently two thirds of our fishing waters have been completely utilized. Most of the remaining areas are over- rather than underexploited. The economic value of oceans is presently dwindling rapidly as marine ecosystems weaken and collapse.

Wetland  ecology group_University of Helsinki_fishing boats on the Atlantic

Fishing boats on the Atlantic Ocean © Stella Thompson

The oceans and seas have long been the Wild West of our planet, where utilization and downright exploitation are permitted with little or no rules (the so-called “tragedy of the commons”). Legislation lags behind the current situation, but founding enormous nature reserves is an excellent way to uphold ocean ecosystem health, at least from the viewpoint of reducing raw material overexploitation. But even huge conservation zones are not sufficient to control the negative effects of climate change.

Marine sanctuaries are an indication of how much we can do to uphold and maintain ecosystem health, especially when national authority and decision-making is combined with international cooperation. Unfortunately the similar protection of land ecosystems is proving more difficult because of intense land use and strict land ownership. The above-mentioned four marine sanctuaries will have a total surface area of approximately 75% of the surface area of the European Union. Conserving such a massive land area would be demanding. International cooperation is the only way forward when dealing with these challenges.


More on the planned marine sanctuaries:

Happy World Wetland Day 2016!

We are celebrating the 45th year of wetland conservation. On February 2, 1971 the Ramsar Convention was signed to uphold wetland biodiversity and functions. More than a billion people make a living from wetlands, so conserving them is essential not only for wildlife but also to us all.

Green sandpipers (Tringa ochropus) flourish in wetlands. © Sari Holopainen

Green sandpipers (Tringa ochropus) flourish in wetlands. © Sari Holopainen

Hunters and conservationists – with shared cause

Do hunters conserve nature? This seemingly controversial issue seems to be a source of never-ending debate. I recently found a text discussing this issue, published in the “Finnish Nature” (Suomen Luonto) magazine as early as 1944. While conservationists and hunters may sometimes be in direct conflict, some shared targets were recognized already in 1944.

Extensive red fox hunting makes it possible for the rare arctic fox to breed successfully in Sweden and Norway. Red fox in an arctic fox habitat in Varanger Peninsula, northern Norway. © Sari Holopainen

Extensive red fox hunting makes it possible for the rare arctic fox to breed successfully in Sweden and Norway. Red fox in an arctic fox habitat in Varanger Peninsula, northern Norway. © Sari Holopainen

O. Hytönen (1944) raised the very same observations that are still apparent. Although hunters kill animals, prey animal populations should not be eradicated by responsible hunting practices. Some hunting actions are straightly connected to nature conservation, such as feeding animals during harsh winters, habitat management and predator control. Currently discussed effect of trophy hunting as an important conservation tool in development countries is an example of an indirect connection: by paying for hunting permits hunters help to maintain local animal diversity. As noted in a recently published paper, banning of trophy hunting can lead to exacerbating biodiversity loss.

In 1953 “Finnish Nature” (Suomen Luonto) published another text on the subject, this time written by G. Bergman. Bergman wrote that the relationships between hunters and conservationists has not always been smooth in Finland, or in other Nordic countries, while no benefits could be gained from these conflicts. Bergman noted that modern game management has several shared principles with nature conservation. He also pointed out that nature conservation and hunting have successfully been managed together in the US. As during Bergman’s times, Europe is still somehow on separate paths, and the situation has become particularly inflamed in some countries. Ironically, Bergman wrote that if we refuse to understand the interests of others, nature conservation aims may be disturbed.

The good old American way

What were the good manners already mentioned by Bergman in America? Maybe he meant the Federal Duck Stamp system established already in 1934. All US hunters must buy a Duck Stamp on a yearly basis, however, whoever can get one. With this small cost the buyers contribute to bird habitat conservation. The US Fish and Wildlife Service advertises that the stamp is “among the most successful conservation tools ever created to protect habitat for birds and other wildlife”. About 1 500 000 stamps are bought yearly, and 98% of the profits are given to the National Wildlife Refuge System for wetland conservation.

Coldwater River National Wildlife Refuge in Mississippi provides great circumstances for wintering ducks. The park is protected, but bird watching is aloud in some parts of the park. Duck hunting is possible outside the park in private lands. © Sari Holopainen

Coldwater River National Wildlife Refuge in Mississippi provides great circumstances for wintering ducks. The park is protected, but bird watching is aloud in some parts of the park. Duck hunting is possible outside the park in private lands. © Sari Holopainen

Another traditional American actor smoothly combining conservation and hunting is Ducks Unlimited (DU), founded by a group of hunters in 1937. DU targets habitat conservation, and is now claimed to be the world’s largest and most effective private waterfowl and wetlands conservation organization according to their website. Most DU members are still hunters.

The land of a thousand lakes

Wetlands have been destroyed for a long time due to differing human interests, also in Finland. Some areas have been lost altogether, while some have lost their value due to e.g. vegetation overgrowth. We still have many lakes left, but shallow eutrophic lakes – the waterbird lakes – are the ones that have been lost most often. Hunters are a group with an interest to construct and restore wetlands. According to a report by the Finnish Wildlife Agency, hunters have constructed or restored about 2 000 wetlands during the past decades. In addition to benefitting game animals, the entire ecosystem benefits. Wetlands also offer several other ecosystem services, including water purification and erosion control.

Many wetlands have been established in Finland to support game animals. Saarikko-wetland in southern Finland is a small, yet very productive duck habitat constructed by the REAH-project (active management of game animal habitats). © Sari Holopainen

Many wetlands have been established in Finland to support game animals. Saarikko-wetland in southern Finland is a small, yet very productive duck habitat constructed by the REAH-project (active management of game animal habitats). © Sari Holopainen

Methods matter

Sometimes hunting itself supports animal populations. For example, hunters can help to maintain animal communities through ecosystem engineering pushed by hunting and the co-evolution of animals and humans. In 2013 a scientific paper showed that in Australia Aboriginal hunting was one of the cornerstones supporting monitor lizard populations. Monitor lizards occur most densely in areas where they are hunted, because of the hunting method used; the burning method creates a patchy mosaic of regrowth in the landscape. In areas with no hunters, occasional lightning strikes burn land in a more homogenous way, and thus also lizards are scarcer. The same practice might also benefit several other desert species. However, in many cases Aboriginals have lost their traditional hunting possibilities, and the loss of these traditional practices sustaining habitats might have contributed to decreasing populations of several desert animal species.

While the debate between hunting and nature conservation has already lasted a long time, and is still on-going, common targets have been raised throughout the process by cooperative actors of both sides. There has always been, and currently still are, differing hunting methods for concerning conservational effects, but it is self-evident that all these practices are not against conservation targets.

Read more:

Enrico Di Minin, Nigel Leader-Williams & Corey J.A. Bradshaw: Banning Trophy Hunting Will Exacerbate Biodiversity Loss. 2015. Trends in Ecology & Evolution. Online.

Connecting Aboriginal Land Use Management Strategies, Mammal Extinction Rates and Shifts in Fire Regimes in a Changing Climate: An Interdisciplinary Approach to Inform Conservation Strategies for Threatened Species in the Australian Western Desert

An interdisciplinary approach to understanding the role of anthropogenic fire in the desert grasslands of Australia

Battle of the foxes

Guest author: Samuli Karppinen

“It was the fifth red fox for the same day”. “Foxes are everywhere”, I thought numerous times during my summer job time in the region of Inari. I was amazed at the number of red foxes (Vulpes vulpes) present in the very northern part of Finland. Nearly every day and no matter where I went, I discovered foxes. I observed foxes close to settlements, and at the end of forest gravel roads. They were mainly lonely adults, but litters of the same year were common too. In addition, the number of red fox dens supported the idea that they succeed well in the northern part of Finland. The arctic fox (Vulpes lagopus) is adapted to life in arctic areas. In Finland, arctic foxes have bred in the regions of Inari and Utsjoki. Arctic fox populations are similar in size to those in Sweden and Norway. Population size at the end of the 1800s was estimated to be 15 000 individuals. At present, the size of the population is estimated to be only 120 individuals. Despite yearly sightings of arctic foxes in Finland, it is nearly 20 years since the last confirmed arctic fox litter. During the summer I began wondering how red foxes influence the declining arctic fox population?

The Arctic fox in Polar Park Norway. © Sari Holopainen

The Arctic fox in Polar Park Norway. © Sari Holopainen

Intensive hunting in the early 1900s was the ultimate reason for the collapse of the Fennoscandian arctic fox population. Even though arctic foxes were protected in 1940, the population did not return to its earlier size. There are several probable causes. Due to changes in reindeer husbandry, arctic foxes cannot exploit the same number of carrions. Global warming causes problems to arctic species and the arctic fox does not stretch the point. Climate change affects snow cover, which reflects on the amount of lemmings. Lemmings are a vital food source for arctic foxes. Arctic fox brood and litter sizes are bigger when the amount of voles and lemming are at their highest point. In addition, global warming is raising the tree line to higher altitudes on the fells. This improves the survival of red foxes in the areas inhabited by the arctic fox.

The red and arctic foxes cannot inhabit the same territory. Research has uncovered that red foxes colonize and annihilate arctic fox dens. The red fox is very adaptable to different habitats and competes for food with the arctic fox. The striking winning picture of the Wildlife Photographer of the Year 2015 –competition underlines the interactions between the two species. The arctic fox is smaller than the red fox and loses the competition for food and habitats. Exploring the number of litters in the last 20 years, it can be seen that while red fox litters have grown, arctic fox litters have declined. The first idea to prevent the spreading of red fox populations is extensive hunting. At the beginning of the millennium, red foxes were intensively hunted in the fell areas of Enontekiö and Utsjoki under the Naali Life – project. The catch quotas appointed by the Ministry of Agriculture and Forestrywere fulfilledvery well by hunters each year. Unfortunately, the hunting alone and the short hunting period in particular had hardly any significance for the arctic foxes.The hunting probably only improved the living conditions of the remaining red foxes and the population might even have strengthened.

Fox cub in Inari. © Samuli Karppinen

Fox cub in Inari. © Samuli Karppinen

Finnish hunters are active in culling semi-predators, like red foxes. It seems that Finnish hunters actively cull semi-predators up to the height of the Arctic Circle. Active culling does not occur in the regions of Inari and Utsjoki, at least in the same scales.Reasons for this are clear: hunters are less enthusiastic, distances are long, the road network is sparse, and snow coveris thick. Maybe hunters of northern Finland don’t feel that culling is as important as hunters in southern Finland do. Red fox culling has to be continuous and intensive year after year for it to have positive effects on the arctic fox population. In 2015, the Finnish wildlife agency, as a part of Management of invasive Raccoon Dogs (Nyctereutes procyonoides) in the north-European countries project, started a project to cull the raccoon dog population in Lapland. A similar project, focused on the red fox, could be a good motivator for local hunters to cull the red foxes.

Research has indicated that lynx (Lynx lynx) regulate red fox populations. Foxes do not succeed in areas where lynx populations are abundant. One of the reasons for red fox success in the fell areas could be a lack of lynx. Unfortunately, it is not realistic to expect that lynx could be the arctic fox’s rescuer. The EU-Life project SEFALO+ (Save the Endangered Fennoscandian Alopex lagopus) has shown that a combination of actions, supplementary feeding, red fox culling, and protection of dens, could cease the decline of the arctic fox population and even enhance it. Nevertheless, I began wondering whether all these actions to save the arctic fox population in the Nordic countries will merely delay their extinction? Their population is small and genetic variation low. Diseases may heavily impact such a small population. Another possible threat to the arctic fox is the occurrence of escaped farm foxes on the mountain tundra. They can breed with wild arctic foxes, but hybrids do not survive in the wild. There are many problems and threats, which Fennoscandian arctic fox population have to face to avoid extinction.

Amphibious sea snakes – torn in between

When I attended the International Wildlife Management Congress (5th IWMC) in Sapporo Japan, I was blown away with a very interesting group of sea snakes: the amphibious sea snakes (Laticaudinae), also known as sea kraits. They possess traits of both land and sea snakes. They are kind of torn between living on land or in the ocean. Their evolution has led to characteristics that enable them to live in both environments, at least for certain periods at a time. But these multiple skills come with a trade-off. For example the locomotion ability in aquatic environments may reduce their terrestrial locomotor ability and vice versa. Even though terrestrial crawling and aquatic swimming are superficially similar activities in snakes, they need different substrates to produce the motion. In general sea kraits move over twice as fast in water than on land.

The ability to move on land is based on both their ventral scales, which are wide just as with land snakes, and their poorly developed tail fins. Sea kraits also use land as their freshwater source. Even though they have a salt gland to excrete the excess salt, they also have to drink freshwater to obtain a proper water balance within their bodies. The freshwater resources that sea kraits use are rainwater, estuaries and sea springs. Estuaries are used by all species, not just to drink freshwater, but also to hide.

The reproduction of amphibious sea snakes differs from true sea snakes (Hydrophinae). Firstly, they are oviparous, whereas true sea snakes are viviparous. Viviparous means that snakes give birth to live young. Oviparous on the contrary means the animal lays eggs and the offspring hatch from them. Sea kraits return to land to mate and lay eggs. The eggs are laid in nests fulfilling certain specific condition.

Sea kraits have lungs for breathing. They therefore need to surface every 15 minutes on average to breathe. The breaking of the surface may take only a split second while a sea krait takes a breath of air and dives again. Most of their time they spend at sea in shallow tropical reefs, which are threatened in several ways. Agricultural and urban runoff, in addition to both organic and inorganic pollution are one of the main threats to shoreline tropical reefs. Many sea krait species are considered vulnerable or nearly threatened. Hopefully we will be able to conserve these interesting and mesmerizing creatures of the oceans before it’s too late.