Factors Affecting the Distribution of the Eurasian Beaver and the North American Beaver in Finland

ABSTRACT Understanding the factors affecting the distribution of species lies at the core of ecology and is becoming increasingly important in the field of applied ecology, such as conservation biology and wildlife management. Distribution patterns of species are largely affected by climate, resource availability, dispersal, disturbance and population dynamics. In my thesis, I studied the factors affecting the distribution of two beaver species in Finland, the Eurasian (Castor fiber) and the North American beaver (Castor canadensis). These species were simultaneously introduced in the 1930s but show a strikingly different distribution and population size at present. I determined the population dynamics, habitat use and availability, and patterns of distribution for both beaver species utilizing data gathered by hunters in beaver monitoring counts and landscape data from a geographic information system (GIS). The results of this thesis indicate that the dynamics of both species is density dependent and migration is an important aspect. In addition, population growth rates have not differed considerably between the species. Beavers seem to disperse slowly from the source populations and a comprehensive water system may enable them to locate habitats close to their natal sites. In addition, habitat use, and thus, available suitable habitats of the two beaver species seem to be similar in Finland, indicating a competition for resources. However, the present environments might affect the different observed patterns, most noticeably that the Eurasian beaver occurs closer to agricultural areas, which may also provide highly suitable habitats for beavers. The importance of deciduous trees and aquatic habitat to beavers was also apparent in my studies. Moreover, I found that the North American beaver has spread longer distances from the introduction sites. The reason for the smaller range of the Eurasian beaver was not, however, completely clear as lack of suitable habitats and barriers to movement do not seem to restrict the spread of the native species. The results of this thesis show that the reasons for the different distribution patterns of the two species are likely complex, and the patterns can be caused by several intrinsic and extrinsic factors. This highlights that it is hard to predict how an introduced species will succeed in new areas. These results can be utilized when planning species introductions, and in wildlife management and the conservation of species. KEYWORDS: Castor fiber, Castor canadensis, distribution, monitoring counts, population dynamics, habitat useTIIVISTELMÄ Lajien levinneisyyteen vaikuttavien tekijöiden ymmärtäminen on keskeisessä osassa ekologiassa, ja on yhä enemmän tärkeää myös sovelletun ekologian aloilla, kuten suojelubiologiassa ja riistanhoidossa. Lajien levinneisyyteen vaikuttavat suuresti ilmasto, resurssien saatavuus, dispersaali, häirintä ja populaatiodynamiikka. Väitöstyössäni tutkin kahden majavalajin, euroopanmajavan (Castor fiber) ja amerikanmajavan (Castor canadensis), levinneisyyteen vaikuttavia tekijöitä Suomessa. Nämä lajit istutettiin Suomeen samanaikaisesti 1930-luvulla, mutta lajien levinneisyys ja populaatiokoot ovat silmiinpistävän erilaisia tällä hetkellä. Tutkin molempien lajien populaatiodynamiikkaa, habitaatinkäyttöä ja -saatavuutta, sekä alueellista sijoittumista, majavalaskennoista saadun datan ja paikkatietoaineistojen avulla. Tulokseni viittaavat siihen, että molempien lajien populaatiodynamiikka on tiheydestä riippuvaista ja migraatio on tärkeä tekijä. Lisäksi populaatioiden kasvukertoimet eivät ole paljoakaan eronneet lajien välillä. Majavat näyttäisivät leviävän hitaasti lähdepopulaatioistaan ja kattava vesistöverkosto saattaa auttaa niitä sopivan habitaatin löytämisessä synnyinalueen läheltä. Myös lajien habitaatinkäyttö, ja näin ollen sopivien habitaattien saatavuus, näyttäisivät olevan samankaltaisia, mikä merkitsisi lajien välistä kilpailua resursseista. Lajien nykyiset elinympäristöt saattavat kuitenkin vaikuttaa havaittuihin eroihin alueellisessa sijoittumisessa, mistä huomattavin on euroopanmajavan esiintyminen maatalousalueiden läheisyydessä. Maatalousalueet voivat näin ollen tarjota sopivia habitaatteja majaville. Lehtipuiden ja vesistöjen tärkeys majaville oli myös nähtävillä tutkimuksissani. Lisäksi havaitsin, että amerikanmajava on levinnyt pidemmälle istutuspaikoiltaan. Euroopanmajavan pienempään levinneisyyteen ei kuitenkaan löytynyt täysin selkeää syytä, sillä sopivien habitaattien saatavuus ja ympäristön esteet leviämiselle eivät näyttäisi estävän lajin levittäytymistä. Tämän tutkimuksen perusteella syyt lajien erilaisiin levinneisyyksiin ovat todennäköisesti monimutkaiset, ja useat lajien sisäiset ja ulkoiset tekijät voivat vaikuttaa levinneisyyteen. Tämä korostaa, että siirrettyjen eläinten menestymistä uusilla alueilla on vaikea ennustaa. Tuloksia voidaan hyödyntää lajien siirtoistutusten suunnittelussa, sekä populaatioiden kannanhoidon ja lajien suojelun suunnittelussa. ASIASANAT: Castor fiber, Castor canadensis, levinneisyys, kannanseuranta, populaatiodynamiikka, elinympäristönkäytt

Differences in habitat use between the native Eurasian beaver and the invasive North American beaver in Finland

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Distribution patterns of the native Eurasian and the non-native North American beaver in Finland - possible factors affecting the slow range expansion of the native species

Distribution patterns of species are affected by resource availability, dispersal, disturbance and population dynamics. The smaller population size and range of the native Eurasian beaver (Castor fiber) compared to the non-native North American beaver (Castor canadensis) in Finland raise questions on reasons for the slower range expansion of the native species. We compared the population growth rates and the spread of both species from their release sites. We also studied the factors possibly affecting the spread of the Eurasian beaver in South western Finland in more detail. We found that the North American beaver has spread longer distances than the Eurasian beaver, but we did not find evidence for movement barriers constraining the expansion rate of the native species. Lack of high-quality habitats does not seem to constrain the expansion to nearby areas either. Despite this, the Eurasian beaver population has grown to a high density close to its reintroduction site, and it has started to spread to novel areas only recently. We conclude that the expansion of the native beaver in Finland seems to be controlled by factors other than those related to barriers for movement: movement behavior and population dynamics, which require further investigation

Differences in habitat use between the native Eurasian beaver and the invasive North American beaver in Finland

Habitat requirements largely determine the distribution and abundance of a species. An invasive species can therefore threaten the survival of a native species, if the two species are similar in niche use. In Finland, the distribution of the invasive North American beaver (Castor canadensis) is approaching the range of the native Eurasian beaver (Castor fiber) possibly creating a threat for the latter. We compared the habitat use of the native and invasive beaver species in Finland in the main distribution of the species and within a smaller area where the species live in sympatry. We compared the used habitats (volume of birch and other deciduous trees and distance to agricultural and urban areas) at beaver lodges and at random locations in the available riparian habitat with (conditional) logistic regression models. Results indicated that the native beaver lodges were located closer to agriculture than those of the invasive beaver. The volume of birch was also slightly greater near the lodges of the native beaver than those of the invasive beaver. However, habitat use of both of the species seemed quite flexible, because the habitat near lodges did not differ much from the available habitat. We conclude that the probability that the North American beaver will invade the distribution area of the Eurasian beaver in Finland depends, at least partly, on the ability of the former to live in proximity to agricultural areas. However, methods other than those related to managing habitat quality may be the best approach to controlling the invasive species.</p

Environmental factors affecting the distributions of the native Eurasian beaver and the invasive North American beaver in Finland

When planning conservation and reintroductions of native species and control of invasive species, it is important to understand the environmental factors affecting species distributions. Habitat suitability largely determines where species can occur, but in addition to habitat and food resources, it is important to also consider human disturbance and climate when mapping possible distributions. We studied the environmental factors affecting the present distribution of the native Eurasian beaver (Castor fiber) and the invasive North American beaver (C. canadensis) in Finland. We compared the role of food resources, aquatic habitat type, anthropogenic disturbance and climate for beaver occurrence with species distribution models. We created maps of suitable areas for the two species and compared how the results would change if these two ecologically similar species were modelled together. We found that aquatic habitat type and climate largely explain the present distributions of the species. In addition, there were differences between the species in their preference for food resources, aspen, birch and grey alder. However, we suspect that the species' reintroduction history, i.e. the differences in the present environment, much explain the differences found between the species. We conclude that when planning possible reintroductions for the Eurasian beaver, factors other than food resources should also be considered. We also suggest that studies on habitat suitability should consider the history of the species and include data from different environments. Thus, more comprehensive information for management planning would be achieved and a better ability to predict the location of optimal areas for the species

Systemic Blockade of ACVR2B Ligands Protects Myocardium from Acute Ischemia-Reperfusion Injury

Activin A and myostatin, members of the transforming growth factor (TGF)-b superfamily of secreted factors, are potent negative regulators of muscle growth, but their contribution to myocardial ischemia-reperfusion (IR) injury is not known. The aim of this study was to investigate if activin 2B (ACVR2B) receptor ligands contribute to myocardial IR injury. Mice were treated with soluble ACVR2B decoy receptor (ACVR2B-Fc) and subjected to myocardial ischemia followed by reperfusion for 6 or 24 h. Systemic blockade of ACVR2B ligands by ACVR2B-Fc was protective against cardiac IR injury, as evidenced by reduced infarcted area, apoptosis, and autophagy and better preserved LV systolic function following IR. ACVR2B-Fc modified cardiac metabolism, LV mitochondrial respiration, as well as cardiac phenotype toward physiological hypertrophy. Similar to its protective role in IR injury in vivo, ACVR2B-Fc antagonized SMAD2 signaling and cell death in cardiomyocytes that were subjected to hypoxic stress. ACVR2B ligand myostatin was found to exacerbate hypoxic stress. In addition to acute cardioprotection in ischemia, ACVR2B-Fc provided beneficial effects on cardiac function in prolonged cardiac stress in cardiotoxicity model. By blocking myostatin, ACVR2B-Fc potentially reduces cardiomyocyte death and modifies cardiomyocyte metabolism for hypoxic conditions to protect the heart from IR injury.Peer reviewe

The learning support features in 2nd grade multiplication : Teacher's guides and teachers as areas of study

Objectives. The aim of this study was to investigate primary school 2nd grade math teacher's guides as well as class teachers, for the learning support features in multiplication. The related research problems are following: How the teacher's guides for the mathematics support students of 2nd grade in learning of the multiplication? How the selected 2nd grade class teachers support the learning features in their multiplication lessons? Methods. This study is divided into two parts. The first part is a qualitative study of 2nd grade math teacher's guides, where three different book series (Matikka 2, Open Kymppi 2 and Tuhattaituri 2) were studied based on the theory-driven content analysis. The exercises from the book series were divided into several studied features: the steps of the arithmetic concept formation, understanding the calculation procedure with whole numbers, sequence skills, Bruner's learning theory and Fuson's language of mathematics. All the features were analyzed with Bereday's comparative analysis. The second part is a case study, where three independent 2nd grade class teachers were studied with the method of stimulated recall. All the teachers were monitored and videotaped during one multiplication lesson and interviewed afterwards about the teaching of multiplication in general and based on the videotaped lecture. The interviews were analyzed with thematic analysis. The results and conclusions. The math teacher's guide Matikka 2 emphasizes the connection between addition and multiplication as well as the learning period during the stage of concrete strategies. Sequence skills were supported the most in the Open Kymppi 2 guide, which had many exercises emphasizing mechanical repetition. On the other hand, the three stages of representation and mathematic languages were less supported in Open Kymppi 2 than in the other guides. The exercises in the Tuhattaituri 2 supported the learning features of the multiplication fairly evenly, although some of the exercises repeated themselves. Numbers 0 and 1 were less supported in Tuhattaituri 2 than in the other guides. All guides supported mental strategies, enactive stage of representation and mathematic languages quite poorly. In the second part of the study, during the multiplication lessons the teachers took well into account the stages of concrete strategies and automated concept formation. On the other hand, the stage of mental strategies did not show up in the results, only when asked separately. In addition, the use of the teacher's guides in the planning of the multiplication lessons was not significant for the studied teachers. Although the lessons supported the learning experience of multiplication quite versatilely, the studied teachers mentioned only some of the supported features in the learning of multiplication.Tavoitteet. Tutkimukseni tarkoitus oli selvittää, miten kertolaskujen oppimista tuetaan kouluissa käytössä olevien opettajan oppaiden harjoituksissa sekä sitä, miten opettajat tukevat opetuksessaan kertolaskujen oppimista. Tutkimusongelmani ovat seuraavat: 1. Millä tavoin matematiikan 2. luokan opettajan oppaat tukevat kertolaskujen oppimista? 2. Miten opettaja tukee kertolaskujen oppimista? Menetelmät. Tutkin kolmen eri kirjasarjan 2. luokan matematiikan opettajan opasta: Matikka 2, Open Kymppi 2 ja Tuhattaituri 2. Keskityin tutkimaan oppaista kertolaskuun johdattelevan sekä kertolaskuja opettavien kappaleiden opettajalle suunnattuja harjoituksia. Oppaiden lisäksi tutkin kolmea kouluissa tällä hetkellä opettavaa luokanopettajaa. Opettajien tutkimukseen käytin stimulated recall -menetelmää. Kuvasin opettajilta yhden kertolaskujen opetustunnin ja haastattelin opettajia erikseen kertolaskujen opetuksesta yleisesti sekä tämän tunnin pohjalta. Tutkimukseni oli laadullinen tapaustutkimus. Luokittelin molempien tutkimusten tulokset teorialähtöisellä sisällönanalyysillä, jonka analyysirunko pohjautui kertolaskujen oppimisen sekä aritmeettisen käsitteenmuodostuksen teoriaan. Opettajan oppaat analysoin Beredayn vertailevalla analyysilla ja opettajien haastattelutulokset teemoittelun avulla. Tulokset ja johtopäätökset. Opettajan oppaiden tuloksena oli, että Matikka painotti yhteen- ja kertolaskujen yhteyttä sekä kertolaskujen oppimista konkreettisten strategioiden vaiheessa ja laskujen ymmärtämistä lukumäärinä. Open Kymppi tuki lukujonotaitoja enemmän kuin muut tutkittavat oppaat. Open Kymppi sisälsi paljon mekaanista toistoa painottavia harjoituksia. Oppaan heikkoutena oli, että se tuki muita oppaita heikommin oppimisen tasoja ja matematiikan kieliä. Tuhattaiturin harjoitukset tukivat kertolaskujen oppimista tasaisesti, mutta osa oppaan harjoituksista toisti itseään. Lukuja 0 ja 1 kertolaskuissa tuettiin Tuhattaiturissa muita oppaita heikommin. Kaikki oppaat tukivat toiminnallista oppimisen tasoa ja kieltä sekä mentaalien strategioiden vaihetta heikosti. Seuraamieni oppituntien ja opettajien haastattelujen tuloksien pohjalta opettajat huomioivat opetuksessaan konkreettisten strategioiden sekä automatisoituneen käsitteenmuodostuksen vaiheet, mutta mentaalien strategioiden vaiheen tietoinen huomioiminen ei tuloksista ilmennyt. Opettajat toivat mentaaleita laskustrategioita esille vasta erikseen kysyttäessä. Toisena tuloksena oli, etteivät opettajat käytä kertolaskujen opetuksensa suunnittelun tukena merkittävästi opettajan opasta. Kuvattujen tuntien harjoitukset tukivat kertolaskujen oppimista monipuolisesti, mutta opettajat nimesivät harjoitusten kertolaskua tukevista piirteistä vain osan

Distribution patterns of the native Eurasian and the non-native North American beaver in Finland—possible factors affecting the slow range expansion of the native species

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Matematiikan opetus innovatiivisissa oppimisympäristöissä - Oppimisympäristön ja pedagogiikan välille kietoutuneet jännitteet

New school buildings are often designed for flexible innovative learning environments (ILEs) to support learning future skills better than before. However, little is known about the relationship between environment and pedagogy. This article examines the relationship between the environment and pedagogy from the perspective of primary school teachers in the context of teaching mathematics. We interviewed 26 teachers from 10 Finnish ILEs and did a thematic analysis. The relationship between the environment and pedagogy forms a complex network of entangled tensions between teacher's inner space, community's social space and physical space. When the ten-sions between these spaces were resolved in a positive way, ILEs enabled pedagogy that diversified mathematics education, improved student cohesion and teachers' well- being at work. However, the ILEs' transformation process often appears to be left unfinished, leading to unsuccessful resolution of tensions. Further, our findings highlight the importance of four-dimensional environmental competence in exploiting the affordances enabled by ILE.Peer reviewe