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Are ecological niche optimum and width of forest plant species related to their functional traits?
Janez Kermavnar, Lado Kutnar, Aleksander Marinšek, Valerija Babij, 2023, original scientific article

Abstract: The ecological niche is one of the central concepts in plant ecology. Understanding which biological traits influence plant niches remains limited, preventing large-scale generalizations. Using a representative pool of 94 herb-layer species frequently occurring in the Slovenian forest vegetation types and an extensive suite of 28 plant functional traits, we tested whether traits serve as predictors for the optimum and width of plant species ecological niche. Niche optimum (mean) and niche width (standard deviation) of each species were derived from community-level ecological indicator values for six environmental gradients, i.e., light, temperature, continentality, moisture, soil reaction and nutrients. We investigated relationships between niche parameters and functional traits through a random forest analysis to account for relatively high trait correlations. Our results suggest that niche optimum and width of forest plant species are related to their functional traits. The two niche parameters were best explained by similar set of traits; however, the relative importance of traits differed substantially. Traits associated with disturbances (frequency and severity), plant dispersal (seed mass, dispersal syndrome), leaf economics spectrum (specific leaf area) and life strategy (CSR scores) showed the highest overall significance in predicting niche optimum and width. Functional traits were, on average, better predictors for niche optimum (average variance explained across all six environmental factors: 20.2%) than for niche width (average variance explained: 7.7%). Intraspecific trait variability, not considered in this study, likely plays an important role in case of niche width. The analyses suggest that, while not all traits impact niche parameters to the same degree, it is crucial to consider traits representing different ecological dimensions and revealing leading patterns of trait coordination. We recommend that the relative importance of traits for species niche parameters should be tested on a larger spatial scale using broader pool of forest understory plants across Europe.
Keywords: ecological gradients, Ellenberg indicator values, Slovenian forest types, trait-environment relationship, understory plants
Published in DiRROS: 09.03.2023; Views: 81; Downloads: 42
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Assessing the heterogeneity and conservation status of the Natura 2000 priority forest habitat type Tilio–Acerion (9180*) based on field mapping
Janez Kermavnar, Erika Kozamernik, Lado Kutnar, 2023, original scientific article

Abstract: Priority habitat types (HTs) within the Natura 2000 network are of the highest importance for conservation in Europe. However, they often occur in smaller areas and their conservation status is not well understood. One such HT is that of the Tilio–Acerion forests of slopes, screes and ravines (9180*). The Natura 2000 study site, Boč–Haloze–Donačka gora, in the Sub-Pannonian region of eastern Slovenia is characterized by a matrix of European beech forests and includes rather small, fragmented areas covered by Tilio–Acerion forests. The goal of this research was to examine the heterogeneity and conservation status of the selected HT through field mapping, which was performed in the summer of 2020. As the conservation of HT calls for a more detailed approach, we distinguished between the following four pre-defined habitat subtypes: (i) Acer pseudoplatanus-Ulmus glabra stands growing mostly in concave terrain, (ii) Fraxinus excelsior stands growing on slopes, (iii) Tilia sp. stands with thermophilous broadleaves occurring on ridges and slopes, (iv) Acer pseudoplatanus stands occurring on more acidic soils with an admixture of Castanea sativa. Field mapping information was complemented with the assessment of habitat subtype characteristics using remote sensing data. The results showed that habitat subtypes differed significantly in terms of area, tree species composition, forest stand characteristics, relief features and the various threats they experienced (e.g., fragmentation, tree mortality, ungulate browsing pressure). The differences between subtypes were also evident for LiDAR-derived environmental factors related to topography (i.e., terrain steepness and Topographic Position Index). This study provides a baseline for setting more realistic objectives for the conservation management of priority forest HTs. Due to the specificities of each individual habitat subtype, conservation activities should be targeted to the Natura 2000 habitat subtype level.
Keywords: forest habitat subtype, monitoring, biodiversity conservation, LiDAR, Slovenia, NATURA 2000
Published in DiRROS: 03.02.2023; Views: 645; Downloads: 58
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Funkcionalna ekologija rastlin: preverjanje izbranih konceptov na primeru rastlinskih vrst gozdnih rastiščnih tipov v Sloveniji
Janez Kermavnar, Lado Kutnar, Aleksander Marinšek, Valerija Babij, 2022, original scientific article

Abstract: Na primeru flore slovenskih gozdov smo obravnavali štiri funkcionalne znake rastlin: specifična listna površina (SLP), vsebnost suhe snovi v listih (VSS), višina rastlin (VIŠ) in masa semen oz. spor (MAS). Prva dva znaka nakazujeta ekonomiko lista (način in učinkovitost izrabe virov), druga dva pa velikost rastlinskih organov. Preučili smo povezave med znaki rastlin in njihovimi fitoindikacijskimi vrednostmi za ekološke dejavnike svetloba (L), temperatura (T), kontinentalnost (K), vlažnost tal (F), reakcija tal (R) in hranila (N). Ugotovili smo statistično značilne korelacije: med SLP in R, N, L, F ter K; med VSS in R ter N; med VIŠ in N, T, R ter F; med MAS in K, R, N ter T. Vzdolž prve osi ordinacijskega prostora smo prepoznali spekter listne ekonomike, ki poteka od vrst z večjimi vrednostmi SLP na produktivnejših, a hkrati senčnih rastiščih, do rastlin z večjimi vrednostmi VSS, prilagojenih na stresne ekološke razmere (npr. nizka reakcija tal ali pomanjkanje hranil oz. vode). Največji prispevek k pojasnjevanju variabilnosti v funkcionalnih lastnostih gozdnih rastlin je imel znak VIŠ, najmanjšega pa znak MAS. Ugotovitve so primerljive z dosedanjimi raziskavami, saj oba izbrana koncepta omogočata prepoznavanje pestrosti oblik in funkcij rastlin na globalni ravni.
Keywords: funkcionalni znaki rastlin, specifična listna površina, vsebnost suhe snovi v listih, višina rastline, masa semena, zelnate rastline, gozdna vegetacija
Published in DiRROS: 29.12.2022; Views: 654; Downloads: 326
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