101 |
Investigating the archaeological implications of environmental change during the Middle Stone Age: a contribution from the geochemical analysis of speleothems in the southern Cape , South AfricaAdigun, Jane Sabina January 2016 (has links)
A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg, 2016. / In current Middle Stone Age research there is interest in understanding whether climatic and environmental factors played a role in behaviours related to subsistence, mobility patterns and material culture production. From a palaeoenvironmental perspective, the southern Cape is recognized as an important study region for exploring the link, if any, between past environmental conditions and key MSA occurrences. The research presented in this thesis aimed to contribute to the existing database of past environments in the southern Cape through the geochemical analysis of speleothems from a previously uninvestigated locality in the De Hoop Nature Reserve. Together, the De Hoop speleothems provide a discontinuous record of environmental change from marine oxygen isotope stage MIS 5a to MIS 3 (and the Holocene). Results from the De Hoop records indicate warm summer rain and C4 vegetation in early MIS 5a (c. 85 ka to 80 ka) but more variability by late MIS 5a (c. 79 ka to 74 ka). At Klasies River main site, also on the southern Cape coast, the upper MSA II is associated with the warm early MIS 5a conditions. At Blombos Cave, another important coastal MSA site, the Still Bay occurring within terminal MIS 5a was linked to warm but more variable late MIS 5a conditions. While early MIS 4 (c. 73 ka to 68 ka) was comparatively cooler, conditions were similar to those in early MIS 5a. From this research, the earlier phase of the Howiesons Poort at Klasies River main site and the Howiesons Poort at Klipdrift Shelter were correlated with the early MIS 4 conditions in De Hoop. By late MIS 4 (c. 67 ka to 60 ka), conditions remained cool, but were seemingly more variable than during the earlier part of this
iii
stage / GR2016
|
102 |
Har signalarter störst förekomst inom eller utanför Dalarnas boreala naturreservat? : En studie om arttätheten av signalarter i Dalarnas barrskogar / Are signal species most abundant inside-or outside the boreal nature reserves? : A study about the density of indicator species in the coniferous forests in Dalarna, SwedenAhlgren, Caroline January 2023 (has links)
Today, it is well known that biological diversity is decreasing worldwide, and the presence of indicator species can identify areas with high biological diversity. Environments with a high presence of indicator species are important to protect and preserve in the form of, for example, nature reserves as these environments indicate high nature values. The aim of this study is to find out whether the coniferous forest's indicator species have the greatest species density and occurrence within the boundaries of the nature reserves in Dalarna, Sweden. The distribution of 10 different indicator species within the coniferous forests of Dalarna, Sweden, was mapped in the QGIS software and the total species density inside as well as outside the nature reserves of Dalarna was compared in the statistical program SPSS. The species density of five selected indicator species was compared inside versus outside of the reserves. The result for the 10 indicator species showed that there was no significant difference between inside versus outside of the reserves, although there were a higher species density per hectare outside the boundaries of the nature reserves. The result for the five selected indicator species showed no significant difference between inside versus outside of the reserves, however, the species density of both R.subpinnatus and P.grossa were higher within the boundaries of the nature reserve. More sightings of indicator species outside the boundaries of nature reserves may indicate that the public is more inclined to report sightings in unprotected areas, rather than reporting sightings in protected areas that have already been established as having high nature values. Many species observations are found just outside the boundaries of the nature reserve, which may indicate that high nature values occur there as well. Further studies about potential buffer zones and their impact on indicator species are encouraged. / Att den biologiska mångfalden minskar världen över är idag välkänt, signalarter är arter som vars närvaro kan tyda på en miljö som kan generera en bra grund för hög biologisk mångfald. Miljöer med hög närvaro av signalarter är viktiga att skydda och bevara i form av exempelvis naturreservat eftersom dessa miljöer tyder på höga naturvärden. Denna studies frågeställning är om barrskogens signalarter har störst arttäthet och förekomst inom naturreservatens gränser. Med hjälp av artobservationer från Artportalen kartlades 10 olika signalarters utbredning i Dalarnas barrskogar i programvaran QGIS. Därefter jämfördes den totala arttätheten för studiens alla arter per hektar innanför och utanför Dalarnas naturreservat i statistikprogrammet SPSS för att se om det fanns en signifikant skillnad mellan respektive område. Även arttätheten för fem utvalda signalarter jämfördes för att se om det fanns en signifikant skillnad mellan de skyddade och icke-skyddade områdena. Resultatet visade att det inte fanns en signifikant skillnad mellan områdena (p=>0,05), även om det var fler artobservationer per hektar utanför naturreservatens gränser. Resultatet för de enskilda arternas arttäthet per hektar och område visade att det inte fanns någon signifikant skillnad mellan områdena, dock var arttätheten för både R.subpinnatus och P.grossa högre inom naturreservatens gränser. Att det förekommer fler observationer av signalarter utanför naturreservatens gränser kan bero på att allmänheten kan vara mer benägna att rapportera in fynd som gjorts i oskyddade områden, i stället för att rapportera in eventuella fynd i skyddade områden som redan har konstaterat höga naturvärden. Många artobservationer återfinns precis utanför naturreservatens gränser vilket kan tyda på att höga naturvärden förekommer även där. Vidare studier kring buffertzoner och dess påverkan på signalarter uppmuntras.
|
103 |
A geographical interpretation of the interplay between urban development, conservation, and sense of place of urban greenspace in Rietvlei Nature Reserve, Tshwane, South AfricaDe Jager, Anna Elizabeth 11 1900 (has links)
Abstract in English, Afrikaans and Zulu / In an increasingly changing world, the attributes of human and physical
environments are critical in assessing human quality of life (HQoL). The research
sources consulted for this thesis point to specific relationships between urban
change, ecosystem services and the HQoL. A variety of models have been
developed in the global North to assist urban planners to manage the benefits and
stressors related to urban shrinkage, ecosystems and HQoL. In the global South
the trend is urban growth rather than shrinkage and few models are available for
this context.
Based on a mixed-method case-study approach, the Rietvlei Nature Reserve,
located in the rapidly-growing urban peripheral zone between the Tshwane and
Ekurhuleni metropolitan areas in the Gauteng province of South Africa, was
selected to assess the benefits and stressors of localised urban development,
conservation and sense of place. The purpose of the assessment was to develop
a Greenspace Stress Model of Urban Impact (GSMUI) that would be of value to
local authorities in managing the interplay of the varied functions of a nature
reserve as a greenspace in the global South. Land-use changes were analysed
using remote-sensing images. Semi-structured interviews were conducted with
purposively-selected key informants to evaluate the functions of the Reserve and
the objectives of the Ecological Management Plan for the Reserve. The benefits
and risks to the Reserve, as well as the sense-of-place aspects, were identified
through semi-structured interviews with 18 purposively-selected key informants,
181 on-site face-to-face semi-structured interviews with visitors to the Reserve,
group discussions with interest groups and electronic surveys involving 365
respondents. Data were also collected through the researcher’s own observations
and her participation in activities at the Reserve. The empirical results of the
research were verified by 14 purposively-selected key specialist informants, who
evaluated and ranked the identified benefits and stressors. Benefits and stressors
were not ranked the same from different perspectives.
Using the results of the empirical research, the researcher was able to merge and
adapt a number of models developed for the management of greenspaces in the
global North in order to develop the GSMUI specifically for the Rietvlei Reserve.
Guidelines were also developed for the application of the GSMUI in geographically
similar greenspaces in the global South. / In ‘n toenemend veranderende wêreld, is die eienskappe van menslike en fisiese
omgewings krities vir die evaluering van menslike lewenskwaliteit (HQoL). Die
navorsing wat geraadpleeg is, het spesifieke verwantskappe tussen stedelike
verandering, ekosisteemdienste en HQoL aangedui ‘n Verskeidenheid modelle is
in die globale Noorde ontwikkel om stedelike beplanners te help om die voordele
en stressors verwant aan ontwikkeling (stedelike inkrimping), ekosisteme en
menslike lewenskwaliteit, te bestuur. Onvoldoende modelle is nog ontwikkel vir die
om die teenoorgestelde neigings in die globale Suide te bestuur.
’n Gemengdemetodes-gevallestudie-benadering is gevolg om die voordele en
stressors van stedelike ontwikkeling, bewaring en sin vir plek in die Rietvlei
Natuurreservaat (geleë in die snelgroeiende stedelike randgebiedsone tussen die
Tshwane en Ekurhuleni Metropolitaanse gebiede in die Gauteng Provinsie van
Suid-Afrika) te ondersoek. Verandering in grondgebruik is deur
afstandwaarnemingsbeelde ontleed. Semi-gestruktureerde onderhoude is met
doelbewus-geselekteerde sleutelinformante gevoer om die funksies van die
Reservaat, sowel as die doelwitte van die Reservaat se ekologiese bestuursplan,
te evalueer. Semi-gestruktureerde onderhoude met 18 doelbewus-geselekteerde
sleutelinformante, 181 semi-gestruktureerde persoonlike onderhoude met
besoekers aan die Reservaat en groepbesprekings is met ereveldwagters en
belangegroepe gevoer, en 365 elektroniese vraelyste is ontleed ten einde die
voordele en risiko’s vir die Reservaat en ook die pleksin te identifiseer. Data is ook
deur middel van waarneming en deelname aan aktiwiteite in die Reservaat
ingesamel. Die empiriese resultate van die navorsing is geverifieer deur 14
doelbewus-geselekteerde sleutelinformante wat die geïdentifiseerde voordele en
stressors geëvalueer en geklassifiseer het. Voordele en stressors is verskillend
evalueer uit verskillende oogpunte.
Die gebruik van die empiriese navorsing het die navorser in staat gestel om ’n
aantal modelle aan te pas wat vir die bestuur van groenruimtes in die globale
Noorde ontwikkel is en te integreer ten einde die GSMUI te skep. Die CSMUI is
spesifiek op die bestuur van die Rietvlei Natuurreservaat gemik. Die navorsing bied
ook ‘n generiese GSMUI met implementeringsriglyne vir geografies-gelyksoortige
groenruimtes in die globale Suide. / Kumhlaba oguquka njalo, isimo sabantu nesemvelo kubalulekile ekuhloleni iqophelo
lempilo yabantu i-Human quality of life (HQoL). Ucwaningo oluhloliwe lukhombise ukuthi
kukhona ubudlelwane obuthile phakathi kokuncipha/ukwanda, inkonzo yobudlelwane
babantu nemvelo kanye ne HqoL. Lokhu kuxhumana kwehlukile kancane ezindaweni
zaseNyakatho nomhlaba (ukungcipha kwedolobha) nezindawo zaseNingizimu nomhlaba
lapho ukwanda kwamadolobha kugqame khona. Kwakhiwe amamodeli ahlukahlukile
khona eNyakatho nomhlaba ukusiza abahleli bamadolobha ukuphatha izinzuzo
nokuhluphayo okuhambisana nentuthuko (ukuncipha kwedolobha), kanye nesimo
sendawo kanye neHQol. Awekho amamodeli awenziweyo ukusiza ukuphatha isimo
esehlukile eNingizimi yomhlaba.
Ngokusebenzisa inqubo exubile, inqubo ye-case study, iRietvlei Nature Reserve
(etholakala lapho kwanda khona ngokushesha amadolobha phakathi kweTshwane neEKurhuleni kwiprovinsi laseGauteng eNingizima Afrika), yakhethwa ukuhlola izinzuzo
nezingcindezi zokuthuthuka kwamadolobha, nokugcina isimo semvelo kanye nobunjalo
obuthile bendawo. Injongo yalolu hlolo bekuwukwenza indawo ebizwa iGreenspace Stress
Model of Urban Impact (GSMUI) ezosiza iziphathimandla zendawo ukuphatha
ukuxhumana okukhona phakathi kwezinhloso ezihlukahlukene zeReserve njengendawo
eluhlaza kwiNingizimu neAfrika yomhlaba. Kwahlaziywa indlela eguqukayo
yokusetshenziswa komhlaba ngokusebenzisa imifanekiso ebheka ikude etholakala kuma
mepi akhombisa indikimba (thematic map). Kwenziwa ama-semi-structured interviews
nababambiqhaza bolwazi ababalulekile ukuhlola ukusebenza kweReserve kanye
nezinhloso zohlelo olubizwa i-Ecological Management Plan for the Reserve. Izinzuzo
nezingcindezi zale-Reserve, kanye nobunjalo obuthile bendawo, kwaphawulwa,
ngokwenza ama-semi-structured interview nabathile ababalulekile abakhethwa abayi 18
ukuxoxa nabo, futhi kwenziwa nama-semi-structured interview ngokubhekana ubuso
nobuso nezivakashi ze-Reserve ezingama 181, kanye nezingxoxo nabaqaphi abathile
besiqiwi (rangers) kanye namanye amaqembu athintekayo. Ulwazi lwaqokelelwa futhi
ngokuthi abacwaningi babheke lokho okwenzekayo kanye nokubamba iqhaza
kwimisebenzi ye-Reserve. Imiphumela yobufakazi bocwaningo yaqinisekiswa ngosolwazi
ababalulekile bobuchwepheshe abangu 14 ababekhethelwe le nhloso, abahlola babuya
babeka ngamazinga izinzuzo nezingcindezi ukwenzela ukuthi abacwaningi babuye
baphinde bakwazi ukwenza enye i-GSMUI.
Ngokusebenzisa imiphumela yobufakazi bocwaningo, umcwaningi wakwazi ukuhlela
kabusha amamodeli amaningana athile enziwe ukuphatha izindawo eziluhlaza eNyakatho
lomhlaba, ukuze enze GSMUI eqondene nokuphatha iReserve laseRietvlei. Ucwaningo
lubuye lwahlinzeka futhi i-GSMUI enabile engasetshenziswa njengemikhombandlela
yezinye izindawo eziluhlaza ezifana nalezi khona eNingizimu yomhlaba. / Geography / Ph.D. (Geography)
|
104 |
Long-term development of different grassland insect communities in Central Europe since the 1950s / Langfristige Entwicklung verschiedener Insektengemeinschaften der Grasflächen Mitteleuropas seit den 1950er JahrenSchuch, Sebastian 14 July 2011 (has links)
No description available.
|
105 |
Slaget om talldungen : om informationen och kommunikationens betydelse i utvecklingen av Haväng och Vitemölla strandbackars naturreservat, 2011–2018 / The battle of the pine grove : about the importance of information and communication in the development of Haväng and Vitemölla strandbackar nature reserve, 2011-2018Ivarsson, Sebastian January 2018 (has links)
I Sverige började processen med att skydda natur redan 1909 och arbetet har fortsatt fram till idag. Även om naturskyddet ska gynna oss alla, är arbetet med det sällan problemfritt. Mitt intresse för dessa problem, hur de kan förstås och hanteras på ett konstruktivt sätt, är utgångspunkten för denna kandidatuppsats. Studien ämnar undersöka hur information och kommunikation har påverkat de närboendes upplevelse till Sand Life, i samband med utökandet och restaureringen av naturreservatet Haväng och Vitemölla strandbackar. I fallstudien undersöks delvis också den konflikt som uppstod i processen. Undersökningen möjliggjordes i tre steg: intervjuer med länsstyrelsen och Sand Lifes medarbetare; enkätundersökning och djupintervjuer med ett antal närboende i Vitemölla. Resultatet tyder på att de närboende som grupp, initialt var negativt inställda till Sand Life. Inställningen tycks bottna i att man upplevt länsstyrelsen och Sand Lifes ursprungliga planer som alltför omfattande och inte tillräckligt förankrade, utifrån ett lokalt perspektiv. Det framkom också att informationen om projektet hade varit bristfällig, vilket möjligen kan kopplas till den inställning man initialt hade. Idag pekar resultaten på att de närboende som grupp är neutrala till försiktigt positiva i sin upplevelse av Sand Life. I huvudsak verkar detta bero på att åtgärderna i naturreservatet blev tilltalande; möjligen kan inställningen också kopplas till att länsstyrelsen och Sand Life tog hänsyn och reviderade skötselplanen samt visade större öppenhet mot de närboende. Eventuellt kan proaktiv information, tydliga avsikter och viljan att utveckla olika planer och projekt i en kontinuerlig dialog med lokalbefolkningen begränsa naturskydd- och förvaltningskonflikters omfattning. / Although nature conservation is supposed to benefit all of us, the work is rarely trouble-free. My concern for these problems is the starting point for this candidacy. The study intends to investigate how information and communication has influenced the residents' attitude to Sand Life, in connection with the development of Haväng and Vitemölla nature reserve. The case study also examines the conflict that arose in the process. The investigation was made possible in three steps: interviews with the county administrative board and Sand Life staff members; questionnaire and interviews with residents around Vitemölla. The result indicates that the residents as a group initially were negative in their attitude to Sand Life. The attitude seemed to be caused by the experience that the county administrative board and Sand Lifes' original plans for the nature reserve was too extensive and not sufficiently anchored, from a local perspective. It was also found that the information about the project had been inadequate, which could possibly be linked to the initial attitude. Today the results indicate that the residents as a group are neutral to cautiously positive in their attitude to Sand Life. Possibly due to the fact that the measures taken in the nature reserve became appealing; the attitude can perhaps also be linked to the authorities revising the care plan and showing greater openness towards the residents. Proactive information, clear intentions and the willingness to develop different plans and projects in a continuous dialogue with locals, can possibly limit the extent of conflicts.
|
106 |
The feasibility of reintroducing African wild dogs (Lycaon pictus) into the Great Fish River Nature Reserve, Eastern Cape, South AfricaPage, Samantha Karin January 2014 (has links)
With a declining population of roughly 3000-5000 individuals in Africa, African wild dogs (Lycaon pictus) are one of the most endangered carnivores in the world. As the global human population expands, it is becoming increasingly unlikely that large portions of land will be set aside for conservation, especially in developing countries. Thus, recent wild dog conservation efforts in South Africa have concentrated on establishing a managed metapopulation. A metapopulation is a group of geographically isolated subpopulations of a species that are managed (using supplementation and harvesting) to mimic natural gene flow. The Great Fish River Nature Reserve (GFRNR) in the Eastern Cape Province of South Africa has been identified as a potential reserve to become part of the national wild dog metapopulation. My research aimed to conduct a feasibility assessment of the long-term (~ 25 years) success of a wild dog reintroduction into the GFRNR. This assessment included biological modelling of wild dogs and their expected prey, and determining the potential anthropogenic threats to wild dogs on the private and communal land surrounding the reserve. I used VORTEX population modelling and determined that the GFRNR is likely to have a wild dog carrying capacity of ~22 individuals. Using a 25-year modelling simulation, the most appropriate wild dog reintroduction scenario would be to reintroduce six females and four males initially and supplement the population with one female and two males in years 3, 10, 15 and 23. In addition, the harvesting/removal of one male and one female in years 10 and 20 would be required to ensure 100% population persistence and adequate genetic diversity. Kudu (Tragelaphus strepsiceros) and bushbuck (Tragelaphus scriptus) are expected to be the two most important prey species for reintroduced wild dogs in the GFRNR. Furthermore, wild dogs are likely to prefer the north-western and south-western sectors of the reserve because of the relatively high prey densities in these areas. However, regular monitoring of both the potential prey and the wild dog populations is essential to ensure persistence of the wild dogs and to prevent prey populations decreasing precipitously. Using structured questionnaire interviews (n = 128), I found that while neighbouring land owners and local communities were generally positive about the potential wild dog reintroduction (56 % of all respondents), several threats to wild dogs were identified along the reserve boundary and on the adjoining unprotected land. Some private landowners and members of rural communities around the reserve (34 %) stated that they would kill any wild dogs that dispersed onto their land. In addition, some respondents (8 %) admitted to believing in traditional uses for wild dog products (e.g. fur) which could result in the illegal killing of wild dogs outside of the GFRNR for traditional purposes. Poaching and the presence of unvaccinated domestic dogs on neighbouring land were also identified as being potential threats to a reintroduced wild dog population. However, such anthropogenic threats appear to be localised to the western and southern boundaries of the reserve. Therefore, by implementing preventative measures (such as anti-snare collars, anti-poaching patrols and vaccination against rabies and canine distemper) the likelihood of such threats occurring can be reduced. I conclude that the GFRNR can sustain a population of wild dogs and successfully contribute to South Africa‘s national metapopulation. An additional reserve will benefit the country‘s metapopulation by increasing the number of wild dogs available for translocation, thereby increasing genetic diversity and overall resilience (to environmental change, disease etc.) of South Africa‘s wild dog population. This will contribute towards the future conservation of this endangered species.
|
107 |
An assessment of the implication of involving local communities in biodiversity conservation : a case study of Blouberg Nature Reserve in Limpopo, South AfricaRampheri, Mangana Berel January 2020 (has links)
Thesis (M.Sc. (Geography)) -- University of Limpopo, 2020 / This work aimed at assessing the implications of involving local communities in biodiversity conservation in Blouberg Nature Reserve (BNR) in Limpopo Province, South Africa. To achieve this objective, firstly biodiversity status before and after involving local communities in conservation initiatives was assessed using multi-temporal medium-resolution Landsat series data and species diversity indices. The results showed that there were significant variations (α = 0.05) in tree species diversity in BNR for before and after involving local communities. For example, tree species diversity was low after involving communities particularly for the years 1996 and 2019. Secondly, benefits and costs of involving local communities in biodiversity conservation as well as their investigate views, perceptions and attitudes BNR management were assessed. The study demonstrated local communities do not obtain sufficient benefits or incur numerous costs from the nature reserve. Despite this, there was considerable support for biodiversity conservation (84.2%) since household respondents still held positive attitudes towards biodiversity conservation in the reserve. For, example most of them indicated that they would report illegal activities to the authorities. However, despite lack of participation by the majority of the household respondents (89.6%) in biodiversity conservation, they demonstrated understanding of the relevance of nature conservation. In contrary, the BNR Manager stated that the local communities received benefits in the form of fuel-wood for special occasions such as funerals and bush meat sold at treasury approved tariffs during culling. However, illegal activities like poaching are still experienced in the nature reserve. Thus, the study underscores the relevance the integrating satellite data and qualitative information in assessing the ecological condition of PAs. Such information can help in biodiversity monitoring and decision-making on conservation of biodiversity.
Keywords: biodiversity conservation; community-based natural resource management approach; ecological status; mapping; satellite data; spatial characterisation; species diversity; statistical analysis.
|
108 |
Léčebna se speleoterapií Ostrov u Macochy / Sanatorium with Speleotherapy Ostrov u MacochyHendrych, Pavel January 2016 (has links)
The diploma project proposes The Children´s Sanatorium with Speleotherapy Ostrov u Macochy which is to take place in the Císařská Cave. Site is located close to the mentioned cave in an exposed natural environment adjacent by urban housing which is represented by dispersed detached houses. An ambition of project is connecting an existing down-entrance to Císařská Cave with design new up-entrance, building of speleotherapy and existing development. There is created a new interconnection which respects and supports a local morphology. The building is situated on the end of connector in direct continuity with existing roads and development which suitably complements because of architecture form based on an archetyp of traditional cottage. The complex offers services for rehabilitation, sanatorium, accommodation and sports for childrens clients and general public too. A project intention was an effort to maximize incorporation the volume to feature of town, townscape with gabled roofs and natural surroundings with preservation high users comfort.
|
109 |
Výskyt ochranářsky významných druhů PR Tetínské skály a jeho ovlivnění environmentálními faktory / The influence of environmental factors on abundance of conservation important species in Tetínské skály Nature ReserveAugustinová, Šárka January 2013 (has links)
Tetínské skály Nature Reserve is one of the major sites for the presence of protected species, which are Dianthus gratianopolitanus, Saxifraga rosacea subsp. Sponhemica and Saxifraga paniculata. My goal was a field survey and data collection about the incidence of these species on the surfaces of rock walls, followed by identification of key environmental factors and description of their impact on the species. Such survey has not been conduncted so far. I used mainly multivariate analysis, PCA and RDA and One-way ANOVA to determine the interrelationships. The analysis results showed significant differences in species abundances influenced by different combinations of environmental factors. The factors with significant influence include cardinal direction. The highest proportion of species abundances showed areas of eastern orientation. Another important factor was shading from vegetation, which proved to have strong negative impact on abundace, especially for species S.rosacea subsp. sponhemica and D. gratianopolitanus. These two variables indicate a preference for sunny areas. Other factors with a significant influence on the occurrence of species are also a presence of soil surface rock wall and a presence of gardens in the area over the rock wall, which greatly increased the proportion of...
|
110 |
Uppföljningsinventering av Karlsviks och Bohults naturreservat - observerade förändringar sedan reservaten bildades / Follow-up inventory of Karlsvik and Bohult nature reserves - observed changes since their establishmentLjungkvist, Max, Trapp, Adam January 2020 (has links)
Abstract Broadleaved forests are highly valuable biotopes with important recreational value and contain rich occurrences of species of conservation concern. To monitor the development of nature values in a forest ecosystem during an interval of approximately ten years, follow-up inventories were carried out, following the first inventories which took place ten years ago in two nature reserves (Karlsvik and Bohult) dominated by broadleaved trees in the county of Halland, Sweden. Indicator species of lichen and moss were searched for and compared to the first inventories. The results show that both reserves contain more indicator species today than approximately ten years ago, though a change in the species composition was observed. In Bohult fewer indicator lichens were observed, although more observations were made of indicator mosses - making the total number of indicator species higher than in the previous inventory. Potential explanations to the differing results of the two reserves were discussed and assessed to be for varied reasons. The observed increased occurrences of indicator species may be due to increased continuity leading to bigger and older trees which make way for more epiphytes. The observed decreased occurrences of indicator species may be due to human activity such as newly carried out clearcutting in close proximity to the reserve (which could lead to edge effects or other environmental stresses), nitrogen deposition or exploitation. An observed threat for both reserves is the increasing growth of norway spruce (Picea abies) which may outcompete broadleaved species and the potential indicator species they may inhabit. / Sammanfattning Ädellövskogar är mycket värdefulla naturtyper med höga rekreationsvärden och med rika förekomster av naturvårdsarter. För att utvärdera förändringen av skogliga naturvärden inom en tidsperiod av ca tio år utfördes uppföljningsinventeringar av två tidigare inventerade naturreservat som domineras av ädellövskog i Hallands län i Sverige. Signalarter av lavar och mossor eftersöktes och jämfördes med tidigare funna signalarter. Båda reservatens ursprungliga inventeringar utfördes för ca tio år sedan och resultaten visar att de båda reservaten nu har fler signalarter än tidigare, samtidigt som en förändring observerades i artsammansättningen då samtliga signalarter ej återfanns. I Bohult observerades färre signalartslavar, men fler signalartsmossor - vilket resulterade i ett större antal signalarter totalt för området. Potentiella förklaringar till de skilda förändringarna diskuterades och bedömdes bero på varierande orsaker. Det större antalet observerade signalarter skulle kunna förklaras av ökad tid för kontinuitet med fler grova och äldre träd som utgör lämpliga substrat för kolonisering av de eftersökta signalarterna. Det färre antalet observerade signalartslavar i Bohult skulle kunna bero på mänsklig påverkan i form av nyligen utförda kalavverkningar i angränsning till reservatet, vilket kan bidra till kanteffekter eller andra påfrestningar på miljön. Kvävenedfall, dikning av vattendrag eller annan exploatering föreslås också som möjlig orsak. Ett observerat hot för båda reservaten var igenväxningen av gran, vilken skulle kunna konkurrera med ädellövträden och de signalarter de kan husera.
|
Page generated in 0.0285 seconds