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Sekä jatkuvapeitteistä että jaksollista metsänkäsittelyä tehdään eri voimakkuuksilla ja erilaisin hakkuutavoin. Ei ole olemassa yksiselitteistä sääntöä, jolla voitaisiin todeta, kuuluuko jokin tietty hakkuutapa jatkuva-peitteiseen vai jaksolliseen käsittelyyn (avohakkuita lukuun ottamatta). Esimerkiksi yläharvennuksia tehdään molemmissa käsittelytavoissa. Kaikkien metsänkäsittelytapojen aiheuttama häiriö on tyypillisesti sitä voimakkaampi, mitä voimakkaampi hakkuu tehdään. Avohakkuut aiheuttavat suurimman haitallisen vaikutuksen sekä luontoon että moniin metsien tarjoamiin ekosysteemipalveluihin. Yhteiskunnan kokonais-edun kannalta jatkuvapeitteisen käsittelyn osuuden lisääminen puuntuotannossa olevissa metsissä on nyky-tutkimuksen valossa kannattavaa. Jatkuvapeitteistä metsänkäsittelyä kannattaa tutkimustiedon perusteella kohdentaa etenkin puuntuotannossa oleviin metsiin, jotka sijaitsevat turvemaalla, ovat virkistyskäytössä, rajautuvat vesistöihin tai rajautuvat suojelualueisiin. Selvää on, että luontokadon pysäyttämiseksi ja ei-puuntuotannollisten ekosysteemipalvelujen turvaamiseksi tarvitaan metsänkäsittelymenetelmien monipuolis-tamisen rinnalla merkittävästi lisäsuojelua.

Despite considerable theoretical interest in how the evolution of phenotypic plasticity should be shaped by environmental variability and stochasticity, how individuals actually respond to these aspects of the environment within their own lifetimes remains unclear. We propose that this understanding has been hampered by experimental approaches that expose organisms to fluctuating environments (typically treatments where fluctuations in the environment are cyclical vs. erratic) for a pre‐determined duration while ensuring that the mean environment over that the entire exposure period is invariable. This approach implicitly assumes that responses to the mean and variance/predictability in the environment occur over the same time‐scale. If this assumption is false, one potential outcome is that phenotypic differences among the treatment groups might arise in response to differences in the mean environment that are present over shorter time periods among those same treatment groups. We illustrate an experimental design that (a) creates variation in the level of environmental predictability, (b) allows for estimation of the time‐scale over which the phenotypic response to the mean environment occurs and (c) permits statistical estimation of the effect of predictability in the environmental variable of interest while controlling for any effect of the mean environment over the relevant temporal scale. Using the clonally reproducing zooplankton species Daphnia magna, we test for within‐generation plasticity in the ability to tolerate high temperature following exposure to multiple temperature treatments with the same overall mean, but where the pattern of fluctuations differed among them. This approach revealed that heat tolerance in Daphnia was not influenced by variability in temperature per se nor the predictability of fluctuations in temperature but adjusted in response to the mean temperature they experienced 24 hr prior to measurement. Our results suggest that conclusions arising from studies that employ a single manipulation of environmental predictability and which cannot consider such potentially confounding effects may be premature. A free Plain Language Summary can be found within the Supporting Information of this article.

Chemical eradication of non-native species has become a widely used method to mitigate the potential negative im- pacts of altered competitive or predatory dynamics on biodiversity and natural ecosystem processes. However, the re- sponses of non-target species can vary from rapid full recovery to delayed or absent recolonization, and little is known about the potential shifts in resource use and trophic diversity of native species following chemical treatments. We used a before-after-control-impact approach to study the effects of rotenone piscicide treatment on abundance and tro- phic niche of benthic invertebrates in three untreated and three treated lakes in central Norway, the latter group hosting non-native roach (Rutilus rutilus) and pike (Esox lucius) prior to rotenone treatment. Based on community com- position data, the relative abundance of invertebrate grazers and collectors decreased while that of predators increased following fish removal in the treated lakes. The stable isotope data indicated minor shifts in resource use of, and tro- phic diversity among, benthic invertebrate communities. While the predatory dragonfly larvae (Odonata) and grazer snails (Lymnaeidae) showed increased δ13C values indicating increased reliance on littoral benthic algae, the collector mayfly larvae (Leptophlebia) showed decreased δ13C values following fish removal in treated lakes. Grazer snails also showed a shift to a lower trophic position, while the predatory dragonflies and collector mayflies showed no changes in δ15N values following fish removal. The community-level isotopic niches of benthic invertebrates showed no consis- tent changes, although the sample-size corrected and Bayesian estimates of standard ellipse areas (SEAC and SEAB) slightly increased in two of the three treated lakes due to an increased range in δ15N. In conclusion, our study findings indicate some changes in species assemblages but minor shifts in the resource use and trophic diversity of benthic in- vertebrate communities following fish removal in rotenone treated lakes Chemical eradication Community dynamics Food web Rotenone Species interactions Stable isotope analysis

Tässä mietinnössä Luontopaneeli keskittyy Suomen pinta-alaltaan suurimman ja siten lajien kannalta merkityksellisimmän elinympäristön eli boreaalisten metsien suojelun kohdentamiseen. EU:n BD-strategiassa mainitut käsitteet vanha metsä ja luonnontilainen metsä eivät ole yksiselitteisiä, ja niiden määritelmiin voidaan perustellusti esittää erilaisia näkökohtia. Tämän ei tule estää rationaalisten suojelusuunnitelmien tekoa. Luontopaneeli korostaa, että käsitteiden määrittelyn sijaan tärkeintä on EU:n BD-strategian tavoitteiden eli luonnon monimuotoisuuden säilymisen ja kokonaisheikentymättömyyden saavuttaminen. Tässä mietinnössä Luontopaneeli esittää laskelman, jolla Suomi voi metsien osalta täyttää oman osansa EU:n BD-strategian tiukan suojelun tavoitteista. Mietinnön johtoajatuksena on ehdottaa suojelun kohdentamiseksi käytäntöön sovellettavissa oleva menetelmä, joka vallitsevan tieteellisen ymmärryksen valossa turvaa parhaiten metsäluonnon monimuotoisuuden säilymisen Suomen kaikissa osissa. Menetelmää noudattamalla tiukan suojelun piiriin saadaan pinta-alasta riippumatta kaikki jäljellä olevat vanhat metsät ja luonnontilaiset metsät sekä yhteensä vähintään 10 prosenttia Suomen metsäisten elinympäristöiden pinta-alasta.

Tässä mietinnössä Luontopaneeli keskittyy Suomen pinta-alaltaan suurimman ja siten lajien kannalta merkityksellisimmän elinympäristön eli boreaalisten metsien suojelun kohdentamiseen. EU:n BD-strategiassa mainitut käsitteet vanha metsä ja luonnontilainen metsä eivät ole yksiselitteisiä, ja niiden määritelmiin voidaan perustellusti esittää erilaisia näkökohtia. Tämän ei tule estää rationaalisten suojelusuunnitelmien tekoa. Luontopaneeli korostaa, että käsitteiden määrittelyn sijaan tärkeintä on EU:n BD-strategian tavoitteiden eli luonnon monimuotoisuuden säilymisen ja kokonaisheikentymättömyyden saavuttaminen. Tässä mietinnössä Luontopaneeli esittää laskelman, jolla Suomi voi metsien osalta täyttää oman osansa EU:n BD-strategian tiukan suojelun tavoitteista. Mietinnön johtoajatuksena on ehdottaa suojelun kohdentamiseksi käytäntöön sovellettavissa oleva menetelmä, joka vallitsevan tieteellisen ymmärryksen valossa turvaa parhaiten metsäluonnon monimuotoisuuden säilymisen Suomen kaikissa osissa. Menetelmää noudattamalla tiukan suojelun piiriin saadaan pinta-alasta riippumatta kaikki jäljellä olevat vanhat metsät ja luonnontilaiset metsät sekä yhteensä vähintään 10 prosenttia Suomen metsäisten elinympäristöiden pinta-alasta.

When a change in the environment occurs, organisms can maintain an optimal phenotypic state via plastic, reversible changes to their phenotypes. These adjustments, when occurring within a generation, are described as the process of acclimation. While acclimation has been studied for more than half a century, global environmental change has stimulated renewed interest in quantifying variation in the rate and capacity with which this process occurs, particularly among ectothermic organisms. Yet, despite the likely ecological importance of acclimation capacity and rate, how these traits change throughout life among members of the same species is largely unstudied. Here we investigate these relationships by measuring the acute heat tolerance of the clonally reproducing zooplankter Daphnia magna of different size/age and acclimation status. The heat tolerance of individuals completely acclimated to relatively warm (28°C) or cool (17°C) temperatures diverged during development, indicating that older, larger individuals had a greater capacity to increase heat tolerance. However, when cool acclimated individuals were briefly exposed to the warm temperature (i.e. were ‘heat-hardened'), it was younger, smaller animals with less capacity to acclimate that were able to do so more rapidly because they obtained or came closer to obtaining complete acclimation of heat tolerance. Our results illustrate that within a species, individuals can differ substantially in how rapidly and by how much they can respond to environmental change. We urge greater investigation of the intraspecific relationship between acclimation and development along with further consideration of the factors that might contribute to these enigmatic patterns of phenotypic variation.

Variation in parameter estimates resulting from different threshold velocities used in heat tolerance algorithm, Timm data on arithmetic scale

Lepidurus arcticus (the Arctic tadpole shrimp) is a vulnerable keystone species in Arctic and alpine water bodies where its occurrence and population size may influence the viability and life history traits of resident salmonids. Using data from a Norwegian mountain hydropower reservoir, Aursjoen, we illustrate how reduced availability of L. arcticus as prey resulted in the reduced condition, growth and delayed maturation of resident brown trout (Salmo trutta). We further link changes in the relative abundance of L. arcticus as prey to changing reservoir conditions, e.g. water level changes in the spring period, thereby establishing an indirect link between reservoir operation regimes and brown trout population traits. While no evidence for decreased brown trout survival was found, the results indicate that alternative brown trout prey resources, i.e. the small chydorid cladoceran Eurycercus lamellatus, do not appear to have successfully offset the caloric loss from reduced consumption of large-sized L. arcticus. Although the fundamental explanation for the observed L. arcticus collapse remains largely unknown, the present findings provide strong evidence that this vulnerable crustacean species can affect the abundance, viability and life history traits of valued resident salmonid populations in oligotrophic alpine lakes and reservoirs exposed to climate- and hydropower-driven changes in water levels and temperature. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

Sexual dimorphism in the Arctic tadpole shrimp, Lepidurus arcticus (Pallas, 1793), was examined. Selective forces shape sexes differently. Males fitness increases by successful mate searching, whereas females increase reproductive potential by attaining large sizes. Sexual dimorphism was examined in 331 L. arcticus from Svalbard, Norway. Males were significantly smaller than females and had significantly smaller carapaces, telsons and cercopods. Lepidurus arcticus is an omnivorous, sometimes cannibalistic, predator. Cannibalism potential effects on sexual dimorphism were studied in the field and laboratory. Cannibalism frequency did not differ significantly between populations. Females dominated in all populations. Male L. arcticus searching for females are at greater risk due to increased chance of encounters with predators and cannibalistic females. Male small body size is advantageous against visually hunting predators, while more robust limbs help males search for females effectively and amplex them. In contrast, the significantly larger female carapace protects her and her eggs from predators.

International audience; Arctic terrestrial ecosystems are generally considered to be species poor, fragile and often isolated. Nonetheless, their intricate complexity, especially that of the invertebrate component, is beginning to emerge. Attention has become focused on the Arctic both due to the importance of this rapidly changing region for the Earth and also the inherent interest of an extreme and unique environment. The three archipelagoes considered here, Svalbard, Franz Josef Land and Novaya Zemlya, delineate the Barents Sea to the west, north and east. This is a region of convergence for Palearctic and Nearctic faunas re-colonising the Arctic following the retreat of the ice after the Last Glacial Maximum (LGM). Despite the harsh Arctic environment and the short period since deglaciation, the archipelagoes of the Barents Sea are inhabited by diverse invertebrate communities. But there is an obvious imbalance in our knowledge of many taxa of each archipelago, and in our knowledge of many taxa. Research effort in Svalbard is increasing rapidly while there are still few reports, particularly in the western literature, from Franz Josef Land and Novaya Zemlya. Nevertheless, there appears to be a surprising degree of dissimilarity between the invertebrate faunas, possibly reflecting colonization history. We provide a baseline synthesis of the terrestrial and freshwater invertebrate fauna of the Barents Sea archipelagoes, highlight the taxa present, the characteristic elements of fauna and the complexity of their biogeography. In doing so, we provide a background from which to assess responses to environmental change for a region under increasing international attention from scientific, industrial and political communities as well as non-governmental organizations and the general public.

Background: Little is known about variation in catch per unit of effort (CPUE) in stickleback fisheries, or the factors explaining this variation. We investigated how nine-spined stickleback (Pungitius pungitius) CPUE was influenced by trap model by comparing the CPUEs of two very similar minnow trap models fished side-by-side in a paired experimental design. Results: The galvanized trap type (mean CPUE = 1.31 fish h–1) out-fished the black trap type (mean CPUE = 0.20 fish h–1) consistently, and yielded on average 81% more fish. Conclusions: The results demonstrate that small differences in trap appearance can have large impacts on CPUE. This has implications for studies designed to investigate abundance and occurrence of fish using minnow traps. peerReviewed

Teimme elokuussa 2019 kauan suunnitellun ja unelmoidun retken Käsivarren Lappiin. Tarkoituksena oli käydä etsimässä ja kartoittamassa Lapin uhanalaisia ja vähän havainnoituja äyriäis- ja nilviäislajeja perustuen osin hyvin vanhoihinkin havaintoihin. Hanna-Kaisa Lakka on kartoittanut Enontekiön äyriäispopulaatioita ja niiden ympäristövaatimuksia jo vuodesta 2012 alkaen. Hannu Ormio on kartoitellut nilviäisiä Kilpisjärven ympäristössä vuonna 2011 ja Katriina Könönen on havainnut ensimmäisen lehtijalkaisäyriäisensä 1990-luvulla yliopiston tunturivesikurssilla ja myöhemmin muutamia havaintoja on kertynyt myös kesäisillä lomareissuilla. Yövyimme Kilpisjärven asemalla ja kartoitimme lähialueen lajistoa Mallan luonnonpuistossa ja Saanalla muutaman päivän ajan. nonPeerReviewed