Browsing by discipline "Maantiede"

Climate change and the threat of an ecological collapse in the near future calls for rapid invention of new methods and tools at the service of informed decision making. Backed by academics Esri, Environmental Systems Research Institute – a multinational company and market leader in GIS (geographic information systems) have spread the word of geodesign as meeting sustainability demands in a variety of forms, allowing design processes based on science as well as values. Esri have been clear on creating a community, collaboratively developing the concept further, to meet global spatially related design challenges. The technological maturity have reach a critical level allowing new forms of fusions between geographic information systems (GIS) and design, but complete technological solutions are not yet available. In the study three research questions are answered. Two are, shortly, what is geodesign and what might it mean for professionals in geoinformatics. The study penetrates the concept of geodesign, using a qualitative and holistic approach. The components central to geodesign are highlighted, keeping the focus on the geospatial dimension of geodesign and the relevance for village planning. Village planning is a design process with deep local roots. The collective vision and will for the future is documented. The study introduces and discusses village planning according to changes in society and the demands it brings upon the villages; decentralized responsibilities and fulfillment of local democracy. The implications of geodesign on the spatial dimension of village planning is answered in the third research question. Finland-Swedish village plans are analyzed in theory-driven illustrative case study. Steinitz framework for geodesign is used as an analytic framework in a theory-driven illustrative case study. Supporting questions included in Steinitz framework, a procedure originally developed for landscape planning but now considered useful for geodesign in general, is used as analytic framework. The framework's analytical contribution is supplemented with interpretation based on knowledge of GIS, geodesign and village planning. The premise in the study is that geodesign have the potential to master a variety design processes while providing a timely concept for village planning. In relation to geodesign, village planning is analyzed as a local endogenous design process, showing high degree of participation. Steinitz framework consists of six models with pairwise relations. On the axis process models-change models a lacking correspondence in the village plans is identified, also a general lack in the holistic approach is identified, especially in systems and process thinking. The village plans also shows distinct strengths. The most prominent is the degree of participation. This means that village planning have potential to be supported by geodesign but also provide a model for citizen-led geodesign. Geodesign can be seen as theoretical and benefits obscure. In this study analytical results and interpretation illustrates what the theoretical approach of geodesign means in practice. Quotes from village plans supplemented with graphics, supporting the comparison of the similarities and differences between Steinitz framework and village planning, highlights the concept geodesign and brings it closer a real application in village planning.

Geographical Information Systems (GIS) are increasingly used to support the emergency planning. GIS methods can be utilized when planning the emergency response system as well as in the emergency management during and after incident. In this study, GIS methods are applied to maritime Search and Rescue (SAR) planning. Traffic amounts are constantly growing in the Gulf of Finland (GoF) and SAR response has to keep up with them. Means to evaluate the SAR response are needed to ensure the adequacy of rescue resources. The voluntary SAR response in in the Finnish waters of the GoF is evaluated. The focus is on the operations of the Finnish Lifeboat Institution (FLI) that is the umbrella organization for voluntary maritime rescue associations in Finland. However, it is hoped that also other SAR operators can apply the presented methods when planning their SAR operations. The main interest is in boating because leisure boats are most often the object of a rescue mission. Timeliness is crucial in emergency operations and thus the SAR response is evaluated here mainly based on the response times. The response times with the current fleet of the FLI are modelled with cost distance methods. Weather factors affect significantly the speed of the Search and Rescue Units (SRU). Therefore, in order to make the results more realistic, different wave height scenarios are included in the cost distance calculations. The wave heights are modelled with two different wind speeds and three different wind directions. The results contain response time maps for the whole study area in different wave height conditions, response times for past incident sites, response times with two units and response times for high incident density areas. Also the number of concurrent incidents in certain sub-areas is observed. According to the results of the thesis the voluntary SAR response in the GoF is generally good. Some improvements would be necessary if the FLI would be the only SAR operator in the area. However, if the units of Finnish Boarder Guard (FBG) are also taken into account the response seems adequate. Therefore, no major changes in the operations of voluntary SAR organizations in the GoF are suggested. Instead, the adequacy of the SAR response elsewhere in Finland could be evaluated. The lower density of SRUs outside the study area may result in inadequacy of SAR response.

Maantieteen ylioppilaskirjoitukset sähköistyivät ensimmäisten joukossa syksyllä 2016. Sähköistymisen myötä maantie- teen ylioppilaskoe tarjoaa uusia monipuolisempia tehtävätyyppejä ja geomedia-aineistoja. Painopisteenä ovat aineisto- jen soveltaminen ja tulkitseminen. Geomedialla tarkoitetaan maantieteellisiä lähteitä, kuten karttoja, tilastoja ja kuvia. Pro gradu -tutkielmani tavoitteena on selvittää kuinka kokelaat osaavat ratkaista uudentyyppisiä soveltavia luonnon- maantieteen tehtäviä ja hallitsevat geomedian käytön osana vastausta. Lisäksi tutkin millaisiin kognitiivisen ajattelun taitoihin tehtävänannot ohjaavat. Tutkimukseni avulla saadaan viitteitä lukionsa päättävien oppilaiden geomediatai- doista, vastausten laadusta sekä pystytään kehittämään ylioppilaskirjoituksia entistä parempaan suuntaan. Työssäni tutkitaan kahta luonnonmaantieteen tehtävää syksyltä 2016 ja keväältä 2017 (N=400). Geomedian käyttöä tutkitaan koko aineistosta ja kokelaiden kirjallisista vastauksista käytetään osaa aineistosta (N=140). Tehtävänannot luokitellaan uudistetun Bloomin taksonomian avulla ajattelun eri tasoille. SOLO-taksonomian avulla luokitellaan sekä kirjalliset että kuvalliset vastaukset. Lopuksi tuloksia verrataan keskenään. Tutkimuksessa kiinnitettiin huomiota eten- kin kuvien ja diagrammien tuottamiseen, aineiston hyödyntämiseen ja viittaamiseen sekä kokelaiden valmiuksiin pär- jätä sähköisissä ylioppilaskirjoituksissa. Tutkimuksessa käytetyt luonnonmaantieteen tehtävät ovat rakennettu niin, että ne sisältävät monipuolisesti erilaisia ajattelun taitoja mittaavia tehtäviä. Siirryttäessä tehtävissä eteenpäin vaaditaan kokelailta korkeamman ajattelutaitojen käyttöä. Tehtävissä tulee soveltaa geomedia-aineistoa, kirjoittaa esseitä ja tulkita aineistoa. Saatujen tuloksien perus- teella kokelaiden geomedian käyttötaidot vaativat vielä harjoittelua ja kuvien tuottaminen osana sähköistä koetta koe- taan vielä haastavana. Omaa ajattelua olisi kaivattu enemmän ja moni vastaus vaikutti ulkomuistista tuotetulta. Haas- tavaksi koettiin rakentaa johdonmukainen, selkeä ja jäsennelty vastaus. Vastaukset sijoittuivat suurimmaksi osaksi yh- den rakenteen vastaustasolle. Vastaustaso nousi korkeammalle SOLO-tasolle tehtävänannon vaatiessa korkeamman ajattelun taitotasoa. Geomedia oli selvästi kokelaille vielä uusi asia. Parhaimmillaan itse tuotetut kuvat olivat informa- tiivisia ja tukivat kirjallista vastausta. Kuvat olivat joko itse piirrettyjä, kuvankaappauksia tai muokattuja kuvankaap- pauksia. Itse tuotetut diagrammit olivat selkeitä ja helppolukuisia sekä esittivät tehtävänannossa kysytyn asian hyvin, mutta niidentulkinta koettiin haastavaksi. Aineistoon ja itse tuotettuihin kuviin oli viitattu harvakseltaan.

The objective of the research is to study how the geopolitical situation during and after the Cold War can be distinguished in the national security strategies and discourses of the United States of America. The end of the Cold War has been understood as a turning point in the study of geopolitics. This represent a transition to an era where the influence and meaning of individual states has diminished, and the world has moved into the era of globalization. The objective of the study is to determine how these changes can be detected in the foreign policy of the United States and the geopolitical discourses. Other specific research questions include how the United States perceives itself in world politics during and after the Cold War and how the difference is visible in the comparison of the national security documents and the public speeches of the presidents. The data that has been chosen for the study represents the National Security Strategies of the United States from the years 1950, 1987, 2000 and 2010. These documents are compared to the State of the Union Addresses from the corresponding years. The research method that is used is critical discourse analysis, which is used with traditional discourse analysis to reveal the power relations behind the discourses. Tabulation is used in the quantitative analysis to study the effects of globalization in the vocabulary. The changes in the discourses and highlighting different values indicate that alternating political goals transform the discourses that are used. The effect of globalization is detected in the altered way of speaking about enemies and allies, about the organizations and alliances that states form and about the economy. The change in the position of the President is present in the documents especially through discourses and argumentation strategies. Compared to traditional and critical geopolitical studies, the documents indicate that the research tradition should place more emphasis on the economy and how it has affected international relations and international security. The significance of economy as a pacifying element is highlighted in the results of the document. The documents indicate that the United States has strived to promote capitalism from the beginning of the Cold War which has created an interdependent political system, which makes conflicts between these states less likely. These changes are visible already before the end of the Cold War, and therefore this specific event does not represent a dramatic shift in the discourses.

Maankäyttö vaikuttaa vedenlaatuun. Kaupungistuminen aiheuttaa pintavalunnan lisääntymistä ja veden laadun heikentymistä. Merkittäviä kaupunkivesissä esiintyviä aineita ja epäpuhtauksia, joiden pitoisuudet kasvavat kaupungistumisen myötä, ovat muun muassa ravinteet ja metallit. Viime aikoina veden laadullisten ja määrällisten muutosten hillinnässä on alettu käyttää uudenlaisia ekologisia huleveden hallintatapoja. Nämä ekologiset hallintatavat pyrkivät veden laadullisten ja määrällisten ominaisuuksien säilyttämiseen maankäytön muutoksista huolimatta. Tutkielmassa kuvataan Helsingin Kuninkaantammen ojavesien fysikaalis-kemiallista vedenlaatua. Tutkimus toteutettiin kolmella pienellä osavaluma-alueella kesä-joulukuussa 2011. Tutkimuksen tarkoituksena on selvittää alueen yleinen vedenlaatu sekä tarkastella vedenlaadussa valuma-alueittain ilmeneviä eroja. Tutkimusalueella tapahtuu lähivuosina merkittäviä maankäytön muutoksia, joiden vaikutuksia vedenlaatuun ja määrään pyritään minimoimaan hyödyntämällä ekologisia hulevedenhallintamenetelmiä. Kuninkaantammi on Helsingin kaupungin hulevesistrategian pilottialue, jossa uudenlaisten menetelmien vaikuttavuutta vedenlaatuun halutaan selvittää. Tutkielma vastaa kysymykseen, mikä on vedenlaatu ennen alueen rakentamista. Vesinäytteistä tutkittiin muun muassa kiintoaine-, ravinne-, metalli- ja hivenainepitoisuuksia. Ojavesien laatu Kuninkaantammessa on pääosin hyvä. Pitoisuudet ovat luonnonpurojen pitoisuuksia korkeampia, mutta hulevesien pitoisuuksiin verrattuna matalia sekä Helsingin kaupunkipuroihin verrattuna keskimääräisiä tai matalia. Maankäyttö valuma-alueilla heijastuu vedenlaatuun. Alueella, jolla on enemmän rakennettua pintaa, fosfori-, nitraatti-, kupari-, nikkeli- ja hivenainepitoisuudet ovat korkeampia kuin vähemmän rakennetulla alueella. Kuitenkin toisella metsäisellä valuma-alueella typpi- ja fosfaattipitoisuudet sekä kromi-, rauta-, lyijy- ja sinkkipitoisuudet ovat näytepisteistä korkeimmat. Metsäisimmällä valuma-alueella epäpuhtauspitoisuudet ovat alhaisimmat. Jotta vedenlaatu myös pysyisi hyvänä ja uudenlaisista hulevedenkäsittelyjärjestelmistä olisi hyötyä, tulee toteutukset mitoittaa riittävän suuriksi. Ympäristöongelmien perimmäinen syy johtuu ihmisten käyttäytymisestä. Veden laatuun vaikuttaa voimakkaasti vesistön sosiaalinen ympäristö, joten pelkät rakenteelliset ratkaisut eivät riitä vedenlaadun kohentumiseen. Yhteiskunnalliset instituutiot, kuten muodollisten instituutioiden ympäristöasenne, vaikuttavat ihmisten käyttäytymiseen. Viestinnällä ja tietoisuuden lisäämisellä voidaan vaikuttaa asenteisiin ja käyttäytymiseen. Vaikuttava viestintä on luonteeltaan positiivista ja joko faktoihin perustuvaa tai tunteisiin vetoavaa. Positiiviset ympäristökokemukset lisäävät ympäristömyönteisyyttä, jolla voidaan saavuttaa mahdollisesti myös kaupunkivesien vedenlaadun kohentumista. Ihmisten tietoisuuden kasvattamiseen kaupunkivesien merkityksestä tulisi kiinnittää huomiota.

Longinoja brook is one of the biggest brooks in Helsinki by catchment area and it is one of the most important spawning areas of brown trout (Salmo trutta) of River Vantaanjoki. The brook and its catchment have undergone significant changes in the process of industrialization and urbanization ever since the 19th century. In the 21st century Longinoja has been restored in order to improve habitats and spawning areas of bown trout, to prevent erosion and to increase the recreational and aesthetic value of the brook. The aim of the thesis was to study the changes in Longinoja's water quality in time and space, the loadings of its side ditches and the effect of land use on areal differences in water quality. The thesis was a part of a survey made by the City of Helsinki Environment Center. The water quality of Longinoja was monitored with an automatic probe 19.4.–6.10.2010 and 4.4.2011–10.1.2012, during which time water samples were collected in every 1–2 weeks. In addition water samples were collected four times a year from different parts of the catchment, in winter, spring, summer and fall in 2010 and 2011. Water quality and loadings of the side ditches and the effect of land use on areal differences in water quality were examined on the basis of water samples collected from the side ditches. Samples were collected four times during growth season in 2011 on rainy days. Intense changes in water quality during snowmelt and especially heavy rains are characteristic of Longinoja. Also hygienic water quality alters greatly. On the basis of median concentrations, the water quality was similar in 2010–2011 than in 2004. Only the concentrations of suspended solids and total phosphorus were clearly higher in 2010–2011 than in 2004. Concentration of phosphate was quite low in comparison with mean concentration of brooks in Helsinki. Compared with Finnish headwaters the conductivity and concentrations of nitrate, iron, copper, zinc and nickel are quite high in Longinoja as they are in other brooks in Helsinki. The loading of suspended solids in spring months is about 8 times greater in comparison with fall months and about 11 times greater in comparison with summer months. The loading of phosphorus in spring months is about 7 times greater compared with fall months and about 9 times greater compared with summer months. Estimated load of suspended solids in Longinoja in year 2011 was 17 100–17 900 kg/km²/y and load of phosphorus 32–34 kg/km²/y. Few relationships between water quality and land use were found because of small dataset. Only low density residential areas could be seen to increase concentration of suspended solids. The Helsinki-Malmi Airport seems to increase loading of nitrogen (TN, NO₃-N, NH₄-N) and nickel and the industrial area in Tattarisuo seems to cause loading of some oxygen consuming contaminants. Based on the results future restoration measures should be focused in the catchments of Longinoja's side ditches Suurmetsänoja, Teerikukonoja and Lentokentänoja. With increasing runoff loading of suspended solids and phosphorus from Suurmetsänoja, phosphate, zinc and copper from Teerikukonoja and suspended solids, nickel and nitrogen from Lentokentänoja is significant.

The changes in our society have had their ramifications in the sense of community in neighborhoods, the latest big social change being the fast alteration of the media environment. Digital forms of communications allow people to communicate almost instantly all over the world. Yet people still tend to form social ties locally, and a growing interest to local themes has been on the rise. The aim of this case study was to find out which underlying housing and socio-economic factors affect the sense of community in neighborhoods, sense of community in areal Facebook groups and the activity of use of these groups, and if there is overlapping in the factors affecting these. The other aim was to examine if communality in areal Facebook groups or the activity of their use increases sense of community in neighborhoods in Helsinki. The research was descriptive, and the objective was not necessarily to make generalizations to the whole study population. Two differing views have shaped the grand theories of sense of community in neighborhoods. In the first wave, there was a division between idealizing the feudal communities, where a strong dependency of neighborly relationships was a given and the relationships of the urban neighborhoods, where residents were seen as isolated and unsatisfied. The changing society shifted the view to examining relationships as a personal network and the form of communities in the overlapping of these networks. These two views differ most importantly in their views of the meaning of distance to social relationships, and the importance of neighborly relationships in general. In the Internet era relationships can be seen to be formed in networks, but neighborhoods and physical proximity still carry a meaning to local relationships. Two different research areas, in terms of common housing types and the amount of children in families, were chosen from neighborhoods in Helsinki; the northern study area around Paloheinä, Pakila and Torpparinmäki, and the southern area around Kallio and Vallila districts. A questionnaire was sent to three different areal Facebook groups and the total amount of responses received was 335. Sum variables were formed to indicate the sense of community among the respondents, sense of community in their areal Facebook group and the use activity of that Facebook group. These variables were then further analyzed statistically and compared to each other and the respondents’ background factors. The responses split up quite evenly between the two study areas, and the background information reported by the respondents reflected the same factors that these areas were chosen by. All the sum variables correlated positively with each other, thus indicating that those who had a greater sense of community in their neighborhood also possessed a greater sense of online community in their areal Facebook group. The respondents from the northern study area had altogether a higher sense of community, sense of community in the areal Facebook group, and a more active use of the group. The results reflected the ones from previous studies, as a higher sense of community was attached to older age, longer residence in the area, apartment ownership, having children in the family and living in a one-family house. Living in a one-family house was also attached to higher sense of community in the areal Facebook groups, as well as having children, long residence in the area and apartment ownership. According to the results in this case study, some of the same background factors produced a higher value in the sense of community in neighborhoods and the sense of community in the areal Facebook groups studied. These shared factors and the correlations between the sum variables indicate that higher sense of community in areal Facebook groups could lead to a higher sense of community in neighborhoods as well. Distance in relationship still possesses a meaning as neighbors form areal groups in social media that can develop into lively communities.

Congestion of traffic is one of the biggest challenges for urban cities in global perspective. Car traffic and traffic jams are causing major problems and the congestion is predicted to worsen in the future. The greenhouse effect has caused a severe threat to the environment globally. On the other hand from the point of view of companies and other economic parties time and money has been lost because of the congestion of traffic. This work studies some possible traffic payment systems for the Helsinki Metropolitan area introducing three optional models and concentrating on the point of view of the economic parties. Central part of this work is formed by a research questionnaire, which was conducted among companies located in the Helsinki area and where more than 1000 responses were gained. The study researches the approaches of the respondents to the area s current traffic system, its development and urban congestion pricing and the answers are analyzed according to the size, industry and location of the companies. The economic aspect is studied by economic theory of industrial location and by emphasizing the meaning of smoothly running traffic for the economic world. Chapter three presents detailed information about traffic congestion, how today s car-centered society has been formed, what concrete things congestion means for economic life and how traffic congestion can be limited. Theoretically it is examined how urban traffic payment systems are working using examples from London and Stockholm where successful traffic payment experiences exist. The literature review analyzes urban development, increasing car traffic and Helsinki Metropolitan area on a structural point of view. The fourth chapter introduces a case study, which concentrates on Helsinki Metropolitan area s different structures, the congestion situation in Helsinki and the introduction of the traffic payment system clarification. Currently the region is experiencing a phase where big changes are happening in the planning of traffic. The traffic systems are being unified to consider the whole region in the future. Also different advices for the increasing traffic congestion problems are needed. Chapter five concentrates on the questionnaire and theme interviews and introduces the research findings. The respondents overall opinion of the traffic payments is quite skeptical. There were some regional differences found and especially taxi, bus and cargo and transit enterprises shared the most negative opinion. Economic parties were worried especially because of the traffic congestion is causing harm for the business travel and the employees traveling to and from work. According to the respondents the best option from the traffic payment models was the ring model where the payment places would be situated inside the Ring Road III. Both the company representatives and other key decision makers see public transportation as a good and powerful tool to decrease traffic congestion. The only question, which remains, is where to find investors willing to invest in public transportation if economic representatives do not believe in pricing the traffic by for example traffic payment systems.

The aim of this study is to examine what kind of mental images are attached to twelve city districts in Helsinki. More accurately put the research questions are 1) to find out how images are portrayed when writing about them in newspapers or spoken about by real-estate agents. 2) What kind of effect mental images has on people and 3) what kind of discursions affects those images. The districts are chosen so that they represent well different areas in Helsinki from their socio-economic and cultural background, as well as architecturally. These districts are Kruununhaka, Töölö, Kallio, Haaga, Oulunkylä, Paloheinä, Viikki, Malmi, Jakomäki, Herttoniemi, Mellunmäki and Östersundom. The research data contains real-estate agents' interviews and articles from Helsingin Sanomat. Real-estate agents provide an interesting viewpoint to different districts with their expertise of neighborhoods and clients. Helsingin Sanomat, for one, portrays the word of media in this research. The influence of media is very powerful, even so that the image it gives of unknown districts becomes 'the truth' of them. The newspaper data contains over 300 articles of different city districts and matters that are associated with mental images of those districts. The real-estate agents' data consist of 43 answers to internet based survey questionnaire. Based on the results it turns out that the real-estate agents are very familiar with almost every district, especially those located in downtown. Most poorly they know about the image of Östersundom, which has been merged to Helsinki most recently. Downtown districts' mental images are perceived positively, as also is the case with residential district Paloheinä and green functionalistic suburb Haaga. The mental images of areas located in eastern or north-western Helsinki, such as Malmi, Jakomäki and Mellunmäki, are perceived most negatively. The impression that newspaper articles give is the same. Articles about those districts very often contain negative expressions even though during the year 2014 aspect of writing has been more positive and has given more peaceful and better image of districts that have bad reputation. The data of real-estate agents' questionnaires also imply that mental images have very great significance for people, especially for the citizens of Helsinki when they are making decisions where to move. Many mental images are also stereotypical and dated. Based on the results can be discovered that mental images are composed by many factors. Firstly, architecture and building time have great influence especially to techno-rationally built areas. They usually have week images for example because of the hard times Finland was going through during the building time. Areas that were built during Empire, Jugend or Functionalistic eras are very popular and perceived positively. They are commonly portrayed by good historical matters. New districts are perceived mostly positively and are sometimes linked to images that are created during city planning. Secondly, geographical location has prejudiced influence on image. Location in eastern or north-western Helsinki dramatically pushes the mental image towards negative conceptions even though it was unsuitable. Thirdly, poverty discursion stigmatizes disadvantaged areas with slummy things such as alcoholism and disquietude. Mental images are altered very slowly but the change is important for example for the city of Helsinki, which is actively trying to create plans for making all city districts' images better.

Some of the most important causes of coastal sand dunes being threatened today are overgrowth of habitats, mechanical wear and construction. The study area, the boreal sand dunes of Vattajanniemi (belongs to Natura 2000 -network), is under heavy trampling (mechanical wear) because the area is in military and recreational use. Plant communities form clear zones parallel to the shore for topographically varied gradient driven by abiotic and biotic factors of stress and disturbance. There has been grazing, harvesting trees and scrub and limitations in trampling as management practices in Vattajanniemi to reduce the mechanical wear and to prevent the overgrowth. This study examined the changes in cover of vegetation, species richness and species composition six years after the management practices were started. The data was collected from 142 vegetation plots in July 2006 and 2012. The plots were located in six habitat types. Descriptive statistics, histograms and Wilcoxon tests were used to discover changes in vegetation cover and species richness between the years. Sørensen Index was used to study the change in species composition in the whole area as well as in different habitat types. The changes in vegetation cover, species richness and species composition (Sørensen Index) were viewed by management practices (grazing, harvesting) and habitat types in boxplots. In addition, the variation Sørensen Index (beta-diversity) with respect to the 2006 total vegetation cover, species richness and the distance to the beach was examined. Generalized linear models were used to explore how much habitat type and management practices (grazing, harvesting) explain the change in total vegetation cover and species richness and the vegetation cover and species richness of the year 2012. Results of this study indicate that total vegetation cover and species richness are statistically significantly increased. As well there has been positive changes in the vegetation cover and species richness of the different functional groups. Vegetation type has been a very significant factor to explain the vegetation cover and species richness in 2012. Grazing has affected differently in different habitat types. The rate of beta-diversity varies between habitats. Species turnover rate was significantly higher in those plots that have been grazed or harvested compared to those plots, which were not. Trampling limitations are considered to increase vegetation cover and species diversity in all habitat types. Management can increase species richness and diversity in coastal dune systems. Each habitat type tolerates disturbance differently and needs its own kind of management plan. Several consecutive years of study, or longer-term (over ten years) research would give a better understanding of which changes are caused by management practices and which are a part of a natural variation.