Comparison of selected landscape ecological forest metrics in two different landscape types

By analysing changes in landscape structure we can trace the influence they have on the evaluation of the diversity function of a forest. In the presented research, it was assessed which indices for computing areas, cores and aggregation tendencies that can be calculated with the Fragstats 4.2 programme best meet our needs, what limits they have and what we should pay special attention to. We considered differences in the resolution of incoming data and different rules for the calculation of raster cells. Both were compared for forests in two different landscape types: Kočevje and Slovenska Istra. The basic surface indices CA and PLAND proved to be the most suitable, while for more demanding purposes, AREA_AM can be used as well. For the evaluation of core areas, basic indices proved to be the most suitable, too, specifically TCA and CPLAND. Other important indices were the index of the number of core areas per surface unit DCAD and indices CORE_AM and DCORE_AM for a more detailed spatial evaluation of core areas, whereas most useful for the evaluation of aggregation tendency proved to be the patch density index PD

Umetni energijski vnosi in ohranjenost primestnih gozdov na Slovenskem

Slovene forestry is concerned with nature conservation, but in the past, the species variety of forests has often been changed and, similarly as elsewhere in Europe, the share of forest with artificial dominance of Norway spruce increased. Based on the spatial model of landscape structure, we estimated the arrangement in conservation of suburban forests in eight Slovene macro regions. In the area of town Kočevje, we assessed artificial energy inputs in the forests lying within one kilometre large area used by inhabitants for daily recreation. In this area, 65 % of forests were categorized as forests with artificial dominance of Norway spruce.Slovensko gozdarstvo je naravovarstveno usmerjeno, toda v preteklosti je bila vrstna sestava gozdov pogosto spremenjena in podobno kot drugje v Evropi se je povečal delež zasmrečenih gozdov. Na podlagi prostorskega modela krajinske zgradbe smo ocenili razporeditev in ohranjenost primestnih gozdov v osmih slovenskih makroregijah. Na območju mesta Kočevje smo ocenili umetne energijske vnose v gozdovih, ki ležijo znotraj kilometrskega pasu mesta, na območju dnevne rekreacije prebivalcev. V tem pasu je kar 65 % gozdov sodilo v kategorijo zasmrečenih gozdov

Krajinske spremembe na območju Pivke, Slovenija

Spontaneous afforestation is one of the biosystemic landscape change processes affecting landscape functioning. The process of overgrowing is highly dynamic, and the temporal dimension of changes in landscape structure can be of key importance for evaluating habitat suitability. A detailed study was carried out in the area of 19.52 km2 within the Pivka municipality, where land use is a mixture of traditional farmland, forests, and extended areas of abandoned former farmland with natural re-growth. In addition, this area is highly important for two bird species: the Barred Warbler (Sylvia nisoria) and the Red-backed Shrike (Lanius collurio). Both species are sensitive to forest spreading and prefer a mixture of extensive meadows with shrubs and hedgerows as their most suitable habitat. Digital BW orthophotos from the 1975 - 2000 period and colour digital orthophotos from 2009 have be enused for on screen digitizing of the EUNIS habitat classes. Indicators of landscape changes were derived from temporal based difference in the landscape structure (different structural indicators based on patch size, shape, distances and patch dynamics). All the details obtained were evaluated based on Earth observation data and GIS supported methods. The most valuable parts of the area for both species are, from a biodiversity point of view, the core forest areas and mixture of meadows with shrubs and hedgerows.Spontano zaraščanje je eden izmed biosistemskih procesov sprememb, ki vplivajona delovanje krajine. Zaraščanje je dinamično in časovna dimenzija sprememb v krajinski zgradbi je lahko ključnega pomena za ocenjevanje primernosti habitatov. Podrobnejšo analizo smo izpeljali na 19,52 km2 izbrane površine v občini Pivka, kjer gre za prostor, kjer je raba zemljišč preplet tradicionalnih kmetijskih zemljišč, gozdov in obsežnih predelov zaraščajočih se kmetijskih površin. Poleg tega je to območje zelo pomembno za dve vrst ptic: pisano penico (Sylvia nisoria) in rjavega srakoperja (Lanius collurio). Obe vrsti sta občutljivi za širjenje gozda, saj je njun habitat preplet ekstenzivnih travnikov z grmičevjem in živicami. Za zaslonsko digitalizacijo habitatnih razredov EUNIS smo uporabili digitalne črno-bele ortofoto posnetke iz obdobja 1975 - 2000 in barvni digitalni ortofoto iz leta 2009. Kazalce krajinskih sprememb smo izpeljali iz razlike v zgradbi krajine iz različnih let (različni kazalniki krajinske zgradbe, ki temeljijo na velikosti in obliki zaplat, medsebojnih razdaljah med njimi in časovni dinamiki). Vse pridobljene podatke smo ovrednotili na podlagi daljinsko pridobljenih podatkov v okolju GIS. Najvrednejši deli prostora so jedrne cone gozdov in prepleti travnikov z živicami in grmovjem

The stability of forest areas in Slovenia as a criterion of landscape diversity and durability

Stabilnost notranjega okolja gozdov je pomemben kazalec biotske pestrosti na krajinskem nivoju, ko se odločamo o tem, ali bi določene gozdove lahko izkrčili. Zaradi tega smo se odločili, da ocenimo stabilnost notranjega gozdnega okolja v Sloveniji med letoma 1975 in 2012, saj so nam na voljo primerljivo dovolj natančni podatki o gozdni maski za teh 38 let. Štiri vrste sprememb pokrovnosti z gozdom (stabilni negozd, krčitve, zaraščanje in stabilni gozd) pojasnjujemo z empiričnim modelom v obliki odločitvenega drevesa, ki upošteva nadmorsko višino, naklon terena, talni tip, oddaljenost vsake celice na rastrski karti od gozdnega roba v izhodiščnem letu, oddaljenost vsake celice na rastrski karti od najbližjega naselja v izhodišč- nem letu. Pojasnjevalne modele smo zgradili po metodi strojnega učenja (Quinlan, 1986) z orodjem See5 (www.rulequest. com). Natančnost izbranega modela je znašala 74,65 %. V letu 2012 so stabilni gozdovi, katerih površina se od leta 1975 ni spreminjala, pokrivali 53 % Slovenije. Izmed vseh spremenljivk najbolje pojasnjujeta spremembo rabe začetna oddaljenost od gozdnega roba in deloma naklon terena. Oddaljenost od naselij in nadmorska višina nimata opaznega vpliva.The stability of forest core areas is an important indicator of biotic diversity on a landscape level in the process of deciding whether certain forests could be cleared. Consequently, we decided to estimate the stability of forest core areas in Slovenia between 1975 and 2012, as we are in possession of sufficiently accurate data to make a comparison of forest cover for these 38 years. Four types of changes in forest coverage (stable non-forest, deforestations, overgrowing and stable forest) are explained with an empiric model designed as a decision tree, which takes into account the altitude, the slope of the terrain, ground type, the distance of each cell on a raster map from the forest edge in the base year and the distance of each cell on a raster map from the nearest settlement in the base year. Explanatory models were built using the method of machine learning (Quinlan, 1986) using See5 (www.rulequest.com). The accuracy of the chosen model was 74.65%. In 2012, stable forests covered 53 % of Sloveniatheir coverage has remained unchanged since 1975. From all the variables, land-use changes are best explained by the initial distance from the forest edge and partially by the slope of the terrain. The distance from settlements and the altitude, on the other hand, do not play a significant role

Forest Patch Connectivity: The Case of the Kranj–Sora Basin, Slovenia

This article features a spatial analysis of forest patches, trees, and shrubs outside forests in part of the Kranj–Sora Basin in central Slovenia. Forest patch connectivity is explored using methods derived from graph theory. The graph nodes represent the forest patches and the edges between them represent the shortest connections calculated using a raster layer containing data on the resistance of individual land-use types. The contribution of an individual forest patch to habitat connectivity and availability is calculated using selected indicators. The findings show that the largest forest patches complemented by smaller patches constitute the basic connectivity tool. Thus, habitat size and close-to-nature structure are vital for the conservation of species over short distances. In conclusion, guidelines are presented for managing and mitigating the effects of further clearing the remaining natural vegetation

Supporting the spatial management of invasive alien plants through assessment of landscape dynamics and connectivity

Invasive alien species are responsible for several negative impacts worldwide. Managing biological invasions is often difficult and the success rate is quite low, but with good planning it is possible to achieve good results. Besides employing the correct methods and techniques, an overall strategy based on landscape dynamics and expected spatial patterns can be fundamental to achieve success. The decision of where to act can be embedded in a general strategy based on several criteria/goals such as control of large populations, connectivity disruption, and so on. This work focused on Acacia dealbata in a Natura 2000 site in Portugal, how the current amount and distribution can affect the spread pattern, and different possible strategies to approach the management. Based on the species dispersal traits, we argue that not only the area but also the perimeter (there fore, the shape) and location of the patches should be considered when fighting the invasion. Three scenarios were designed and compared using the perimeter–area ratio, a landscape dynamics analysis, and a connectivity index. Results show that removing the patches with higher perimeter–area ratio (mostly small satellite patches) would be more impactful than removing the larger patch or removing random intermediary perimeter–area patches first. After this approach based on landscape dynamics, the employment of a connectivity assessment provided an ordered list of patches to remove sequentially. Overall, this approach can be valuable in the early steps of the planning process, supporting better decisions regarding the available resources and contributing to maximize the effectiveness of the actio

Comparison of selected landscape ecological forest metrics in two different landscape types

By analysing changes in landscape structure we can trace the influence they have on the evaluation of the diversity function of a forest. In the presented research, it was assessed which indices for computing areas, cores and aggregation tendencies that can be calculated with the Fragstats 4.2 programme best meet our needs, what limits they have and what we should pay special attention to. We considered differences in the resolution of incoming data and different rules for the calculation of raster cells. Both were compared for forests in two different landscape types: Kočevje and Slovenska Istra. The basic surface indices CA and PLAND proved to be the most suitable, while for more demanding purposes, AREA_AM can be used as well. For the evaluation of core areas, basic indices proved to be the most suitable, too, specifically TCA and CPLAND. Other important indices were the index of the number of core areas per surface unit DCAD and indices CORE_AM and DCORE_AM for a more detailed spatial evaluation of core areas, whereas most useful for the evaluation of aggregation tendency proved to be the patch density index PD