Effects of released farmed mallards on species richness of breeding waterbirds and amphibians in natural, restored and constructed wetlands

Common practices in current game management are wetland restoration and creation, as well as releases of quarry species. We studied the impact of releases of mallard ducklings on species richness of wild waterbirds and amphibians on three types of wetlands: natural, constructed and restored. Data on species richness, macrophyte cover and water characteristics (total phosphorous and pH) were collected at 32 sites in an agricultural landscape in southern Sweden. In total, 14 species of waterbirds were recorded, ranging from zero to seven per wetland and survey. Amphibians were present in 24 of the 32 wetlands; in total five species were found, ranging from zero to three per wetland. By using generalized linear modelling we found that wetland type best predicted waterbird species richness. Constructed wetlands had significantly more waterbird species, regardless of whether they were used for mallard releases or not. There were breeding amphibians in 62% of natural, 100% of restored and 77% of constructed wetlands. Breeding amphibians were present in 84% of wetlands without, and in 62% of wetlands with releases. However, included variables did not explain amphibian species richness in the wetlands. Releasing large numbers of mallards on a wetland and providing food ad libitum is likely to affect water quality, nutrient availability and predation pressure. Indeed, phosphorous levels were significantly higher in release wetlands, but no differences were found between wetland types.This means that mallard releases may increase nutrient loads in environments that are already eutrophied. However, in our study system releases did not influence species richness of waterbirds and amphibians locally. Constructing wetlands for mallard releases can thus have positive local effects on species richness.Peer reviewe

Evolutionsundervisning i den engelska skolan – undersökning av elevernas kunskap om evolution

Inget inom biologi är förståligt förutom i ljuset av evolution. Tyvärr börjar evolutionsundervisningen alldeles för sent i skolan samtidigt som det finns organisationer som jobbar för att underminera evolutionsteorins giltighet. Detta genom att försöka få kreationism och Intelligent Design som alternativ till evolutionsteorin på naturvetenskapliga lektioner, vilket riskerar leda till att elevers kunskap om och förståelse för evolutionen minskar. Syftet med detta arbete var att genom en enkät kontrollera engelska elevers kunskaper om livets uppkomst och utveckling samt få reda på deras eventuella kreationistiska tankar eller missuppfattningar i ämnet. Arbetet ska även ge tips och råd till lärare som på naturvetenskapliga lektioner ska undervisa i evolution. Enkätundersökningen genomfördes på elever från tre olika klasser i Brighton, England. Elever kryssade även i om de var pojke/flicka och om de ansåg sig vara religiösa eller inte för att finna eventuella skillnader mellan årskurs, kön och religion. Två intervjuer genomfördes med James Williams, från Sussex University för att få information och tips till lärare i evolutionsundervisning. Enkätsvaren visade att elever överlag har en relativt god kunskap om livets uppkomst och utveckling utan större kreationistiska tankar. Däremot visade svaren på dålig uppfattning om vad som är vetenskap eller inte. Svaren visade att ju äldre eleverna var och ju mer biologiundervisning de hade desto större var sannolikheten för ett rätt svar. En annan skillnad var att religiösa elever oftare svarade sant på kreationistiska påståenden. Evolutionsundervisning måste börja så tidigt som möjligt för att så hög förståelse som möjligt ska uppnås. Lärare måste ha en god kunskap för att kunna argumentera för evolutionen. De måste även ha kunskap om vetenskapsteori och vara tydliga med det vetenskapliga språket. Det viktigaste att tänka på för naturvetenskapliga lärare i evolutionsundervisning är att behandla alla med respekt och vara tydliga med vad som ska läras ut på lektionerna och varför

Large-scale releases of native species : the mallard as a predictive model system

Human alteration of natural systems, and its consequences are of great concern and the impact on global ecosystems is one of the biggest threats that biodiversity stands before. Translocations of invasive species, as well as intraspecific contingents with non-native genotypes, whether they are deliberate or unintentional, are one such alteration and its consequences are continuously being assessed. The mallard (Anas platyrhynchos) is the most numerous and widespread duck in the world and a flagship in wetland conservation. It is also an important game species which is heavily restocked for hunting purposes, especially in Europe where over three million ducklings are released every year. Because of its hunted status, its abundance, and the number of released individuals, it can serve as a model species to study effects of releases, both for conservation and restocking for hunting, on wild populations. In this thesis the status of the mallard was assessed in the Nordic countries and the effects of releases on the wild populations were studied by mining historical ringing data, comparing morphology of present-day wild, farmed, and historical mallards, and analyzing phylogeography of wild and farmed mallards in Europe. The status of the mallard population in the Nordic countries are generally good, however, a joint effort of European countries is needed to monitor and manage the population. A significant difference between wild and farmed mallards concerning longevity, migration, bill morphology and genetic structure was also found, together with signs of cryptic introgression of farmed genotypes in the wild population with potential fitness reduction as a result. The effect is however limited by that only a fraction of released farmed mallards reach the breeding season due to low survival. A natural captive environment is crucial to keep individuals wild-like with high survival rates after release. However, with an introgression of potentially maladapted farmed genotypes leading to a reduction in fitness, a low survival of released mallards would favor the wild population. A legislative change regarding obligation to report numbers, provenance, and release sites of farmed mallard should be considered, together with practical solutions of ringing and genetic monitoring of released mallards

Hur utsatta är utsatta änder?

Utsättningar av djur och växter har förekommit mycket länge. Slottens svandammar har kommit till av detta skäl, godsen har satt ut jaktbart vilt. Jordbruk och skogsbruk bygger på idén att plantera ut för att sedan skörda, och även naturvården ägnar sig åt ”stödutplanteringar”. Ingen fågelart sätts ut i så stora antal som gräsanden. Men vad är det för änder det handlar om? Vilka blir effekterna

Effekter av utsättningar av farmade änder ämnade för jakt

I över 40 år har det i Sverige pågått ett storskaligt, ekologiskt experiment där hundratusentals gräsänder årligen har fötts upp i fångenskap och satts ut i våtmarker för att öka på den jaktbara populationen. Genom uppfödning i fångenskap riskerar man att de farmade gräsänderna blir annorlunda gentemot de vilda. För att studera effekterna på den vilda populationen av dessa utsättningar startades 2010 ett doktorandprojekt finansierat av Naturvårdsverket. Projektet kom fram till att farmade änder skiljer sig i beteende och utseende mot de vilda. Det går även att genetiskt skilja på farmade och vilda gräsänder. Ett nytt projekt startades 2017 för att vidare studera effekter av utsättningar, nu även på miljön och den biologiska mångfalden där änderna sätts ut. Projekten om effekter av utsättningar av farmade änder involverar forskare från olika lärosäten i Sverige, men också från flera olika europeiska länder. Ett nära samarbete med olika lokala privata aktörer som uppfödare, markägare, jägare och viltmästare samt större organisationer somViltmästareförbundet och Svenska Jägareförbundet är avgörande för projektens framgång. Att kommuniceraresultaten på så väl vetenskapliga konferenser som för icke akademiker involverade i projekten samt i undervisning på Högskolan Kristianstad och på gymnasieskolor har hela tiden varit en målsättning. Projekten har också en tydlig plats i forskningsmiljön MABH vars kompetenser inom t.ex. vattenvård, sjukdomsspridning och landskapsutnyttjande kanknytas till projekten

Survival of wild and farmed-released mallards : the Swedish example

More than three million farmed mallards are released annually for hunting purposes in Europe. The ecological impact of these releases depends on how many birds survive to join the wild breeding population. We estimated annual survival in farmed-released and wild-caught Swedish mallards, using mark-recapture data. In 2011–2018, we ringed 13,533 farmed ducklings before release (26.5% recovered). Most recoveries were birds shot at the release site, while only about 4% were found >3 km away. In 2002–2018, 19,820 wild mallards were ringed in Sweden, yielding 1369 (6.9%) recoveries. Like in farmed-released birds, most recoveries were by hunting, but 91.1% of recovered wild mallards were >3 km away from the ringing site. Annual survival rate in farmed-released mallards (ringed as pulli) was 0.02. In wild mallards (ringed as fledged or fully grown), annual survival was lower in females (0.64) than in males (0.71). At two sites in 2018, farmed ducklings were released in two batches 3 weeks apart to study the effect of early versus late release date, while controlling for body condition (BCI). Ducklings released early had a higher BCI and were recovered earlier (lower longevity) than those released late. Individual BCI and longevity were not correlated in recovered ducklings. Based on our estimate of annual survival in farmed-released mallards, a substantial number, i.e., 5000 (95% CI, 3040–6960), join the wild population annually. Despite being fed, a large proportion of released ducklings does not survive until the hunting season. Early releases may maximize pre-hunting survival. Repeated releases may prolong hunting opportunities and increase hunting bags

Evaluation of Nutritional Quality and Sensory Parameters of Meat from Mallard and Four Species of Wild Goose

Future challenges concerning protein supply for food and feed include the management of all currently available resources. In Sweden, wildfowl are hunted for several reasons, one of which is to protect growing crops. In this study, meat from wild geese and mallard was evaluated with respect to its quality and sensory parameters. The most pronounced sensory differences were between meat from the barnacle goose and the Canada goose and between meat from mallards that were farmed and born wild. This study also provides measurements of values for the nutritional and heavy metal contents of the meat from these wildfowl species in order to elucidate their possible use as modern foods

Average number of lamellae (±1 standard deviation) per position ( = 1 centimeter) by group and sex in mallards.

<p>Position 1 is in the most proximate part of the maxilla. In position 2, historical males were statistically different from farmed ones, and nearly so (<i>p = </i>0.051) also from present-day wild males. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115143#pone-0115143-t002" target="_blank">Table 2</a> for sample sizes. Different letters indicate significant difference of means within each group and sex.</p><p>Average number of lamellae (±1 standard deviation) per position ( = 1 centimeter) by group and sex in mallards.</p