Original scientific paper
Pedophysiographic Features and Heavy Metal Content (Pb, Zn, Cd and Cu) in Spruce Forests of Northern Velebit and Štirovača
Darko Bakšić
orcid.org/0000-0003-3190-8321
; Šumarski fakultet Sveučilišta u Zagrebu, Zavod za ekologiju i uzgajanje šuma, Svetošimunska 25, HR-10 000 Zagreb, HRVATSKA
Ivan Perković
; Šumarski fakultet Sveučilišta u Zagrebu, Zavod za ekologiju i uzgajanje šuma, Svetošimunska 25, HR-10 000 Zagreb, HRVATSKA
Nikola Pernar
; Šumarski fakultet Sveučilišta u Zagrebu, Zavod za ekologiju i uzgajanje šuma, Svetošimunska 25, HR-10 000 Zagreb, HRVATSKA
Joso Vukelić
; Šumarski fakultet Sveučilišta u Zagrebu, Zavod za ekologiju i uzgajanje šuma, Svetošimunska 25, HR-10 000 Zagreb, HRVATSKA
Boris Vrbek
; Hrvatski šumarski institut Jastrebarsko, Zavod za ekologiju šuma, Cvjetno naselje 41, HR-10 450 Jastrebarsko, HRVATSKA
Abstract
The largest and the most coherent complexes of natural spruce stands in Croatia are currently distributed in the altimontane and subalpine vegetation belt of Velebit over an area of 3165 ha and altitudes ranging from 1100 to almost 1600 m.
Past phytocoenological research into spruce forests in northern Velebit distinguishes three different associations: frost valleys of Štirovača and Apatišanska Duliba support the altimontane spruce forest with bastard agrimony (Aremonio-Piceetum Horvat 1938), shallower sink holes and slopes descending from the surrounding tops contain the altimontane-subalpine spruce forest with Laserpitium krapfii (Laserpitio krapfii-Piceetum Vukelić et al. 2010), while rocky tops, hips, karrens and ridges feature the subalpine spruce forest with small-reed (Calamagrostio variae-Piceetum Bertović 1975). These associations are distributed as azonal, microclimatically and edaphically conditioned associations, of which spruce forest with bastard agrimony occurs in the belt of Dinaric beech-fir forest (Omphalodo-Fagetum) while the two others grow in a higher belt of subalpine beech forest with buttercup (Ranunculo platanifoliae-Fagetum). Their mutual differences result from ecological factors which are decisive for their occurrence and distribution. Of these, the edaphic relationships which we explored in this work draw particular interest.
Composite samples were taken from the top layer up to 5 cm deep (13 composite samples composed of 9 individual samples each), pedological profiles were opened (11 profiles), and soil samples were taken by pedogenetic horizons within pedological research in three spruce communities: altimontane spruce forest with bastard agrimony (Aremonio-Piceetum), altimontane-subalpine spruce forest with Laserpitium krapfii (Laserpitio krapfii-Piceetum), and subalpine spruce forest with small-reed (Calamagrostio-Piceetum) in the area of northern Velebit and Štirovača. Composite samples, taken from the top soil layer up to 5 cm deep, consisted of 9 samples, each taken at a distance of 1 m in a cross pattern.
Soil samples were analyzed by means of the following laboratory methods: determination of pH values (HRN ISO 10390:2005), determination of CaCO3 content (HRN ISO 10693:2004), determination of organic and total carbon and nitrogen with dry combustion (HRN ISO 10694:2004, HRN ISO 13878:2004), determination of concentrations of Pb, Zn, Cu and Cd (HRN ISO 11466:2004), and determination of the granulometric soil composition (HRN ISO 11277:2004). Descriptive statistics were made for all the samples by the investigated phytocoenosis. Variance analysis was used to test the differences between the composite soil samples for the layer of up to 5 cm in depth. Statistica 7.0 software was used for this purpose.
The analyses of composite soil samples taken from a depth of 5 cm in three different spruce communities (Aremonio-Piceetum, Laserpitio krapfii-Piceetum and Calamagrostio-Piceetum) showed than the lowest pH value was recorded in the community Aremonio-Piceetum, followed by the community Calamagrostio-Piceetum, while the highest value was recorded in the community Laserpitio krapfii-Piceetum. The average pH (H2O) value in the community Aremonio-Piceetum reaches 4.35, in Laserpitio krapfii-Piceetum it is 5.56 and in Calamagrostio-Piceetum it is 5.23. In terms of pH values for soil depths of up to 5 cm, the communities Aremonio-Piceetum and Laserpitio krapfii-Piceetum (pH H2O, p=0.01447; pH CaCl2, p=0.01668) show a statistically significant difference.
In all the communities the surface soil layer is richly humous and well supplied with nitrogen. It is the richest in the community Calamagrostio-Piceetum, where the average value of C org amounts to 131.6 g kg–1 and N tot. to 9.3 g kg–1 (Table 3). The C : N ratio in all the three communities is favourable and ranges between 11 and 15.
The average depth of the humus-accumulative horizon amounting to 6.5 cm is the lowest in the community Aremonio-Piceetum. It is higher in the community Laserpitio krapfii-Piceetum where it reaches 7.5 cm and the highest in the community Calamagrostio-Piceetum, where it is 21 cm. The content of pH values, C org., N tot. in the hummus-accumulative horizon shows similar values and an identical trend to composite soil samples at a depth of up to 5 cm. In terms of the argyle-accumulative and cambic horizon, the lowest pH value is observed in the community Aremonio-Piceetum, where the average pH (H2O) value is 5.30. In the community Laserpitio krapfii-Piceetum, the average pH (H2O) value is 6.92. The highest pH value is observed in the community Calamagrostio-Piceetum, where the average pH (H2O) value reaches 7.21, but it is only one profile opened in the shallow and distinctly skeletal calcocambisol. All the soils have a texture ranging from silty to clayey loam.
Soil reaction was the only parameter to show statistically significant differences for the top soil layer. These differences relate to the communities Aremonio-Piceetum and Laserpitio krapfii-Piceetum. The lowest pH value in the community Aremonio-Piceetum is conditioned by acid parent material, flat relief which additionally favours the podzolization process in the perhumid climate, while specific microclimatic conditions, frost sites and high air humidity cause more intensive accumulations of raw humus. In relation to the pH reaction, the lowest acidity is displayed by the association Laserpitio krapfii-Piceetum, as confirmed by phytocoenological research (Vukelić et al. 2010), according to which this community, compared to others, has the biggest number of species of the order Fagetalia. These species are dominant in adjacent, mainly neutrophilic beech and beech-fir forests.
All the three studied communities, Aremonio-Piceetum, Laserpitio krapfii-Piceetum and CalamagrostioPiceetum, manifested high Pb contamination in the surface soil layer of up 5 cm. The average Pb content (median) in the community Aremonio-Piceetum amounts to 54.5 mg kg–1, in the community Laserpitio krapfii-Piceetum to 65.0 mg kg–1, and in the community Calamagrostio-Piceetum to 54.7 mg kg–1. The top soil layer of 5 cm in the communities Laserpitio krapfii-Piceetum and Calamagrostio-Piceetum also manifested high Zn and Cd contamination. The average content (median) in the community Laserpitio krapfii-Piceetum for Zn is 101.0 mg kg–1 and for Cd it is 1.0 mg kg–1, whereas in the community Calamagrostio-Piceetum it is 75.0 mg kg–1 for Zn and 1.9 mg kg–1 for Cd.
Keywords
spruce communities; pedophysiographic features; heavy metals; Velebit
Hrčak ID:
68071
URI
Publication date:
8.4.2011.
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