Ecosystem services are inherently defined mutual interaction between ecological and social systems because only those ecosystem processes that contribute to the fulfillment of human needs, are defined as ecosystem services [1] [2] [3] [4]. The ecosystem services approach offers the ability to explore the influence of land use and practices on natural capital stocks, on the processes that build and degrade these stocks, and on the flow of ecosystems services from the use of these stocks [5]. Service-providing ecosystems are denoted as natural capital [6] [7]. Ecosystem services linked to natural capital can be divided into three main categories (provisioning, regulating and cultural) [2] [5]. Agroecosystem services are the multiple goods and services provided to humanity by nature in combination with additional anthropogenic inputs in agricultural systems [2]. Concept of agroecosystem service combines environmental and socio-economic approach to the analysis and evaluation of natural capital. For practical use as well as legislative use of the concept of agroecosystem services in planning and prospective studies, qualitative and quantitative analysis and evaluation of agroecosystem linked to spatial visualization at the required level are essential [7]. The concept of agroecosystem services receives increasing attention in recent years with an emphasis on national assessment. Following this trend, an integrated evaluation and mapping of agroecosystem services was carried out in the Slovak Republic [8].

Agricultural systems are intensely managed by humans and are more controlled and regulated than majority of the other ecosystems [5]. Traditionally, agroecosystems have been considered primarily as sources of provisioning services, but more recently their contributions to the other types of ecosystem services have been recognized [2] [9] , such as regulating and cultural services [5] [10] [11]. Recent conceptual works used the ecosystem services approach to highlight the importance of pedosphere to the human well being and prosperity [12] [13]. We consider the agroecosystem not only as means of production but also as a part of the natural environment, where the pedosphere has functions other than food production [14] [15]. The agroecosystem based on soil is multifunctional in all conditions, both in terms of its processes and functions and services [16]. The cascade model developed by Haines-Young and Potschin [17] demonstrated how soil functions can contribute to ecosystem services. According to Greiner et al. [18] soil and their functions are critical to ensure the provision of ecosystem services. Nevertheless, agroecosystem services at the national level, were not assessed on the context of the Slovak Republic. In Slovakia, Juráni [19] , Bujnovský et al. [20] , Makovníková, Barančíková and Pálka [21] and Barančíková et al. [22] have been also dealing with assessment of soil functions that are the basis for the evaluation of agroecosystem services. These authors define a minimum collection of soil indicators for sufficient assessment of soil functions. These indicators form our basis for agroecosystem services evaluation.

While the concept of natural capital and economic services are widely accepted and their potential contribution to better environmental management is also acknowledged [9] [23] [24] , their practical applications such as distribution and mapping are still insufficient and limited. The models and their map presentations should reflect biophysical factors on one hand, but on the other hand they should be applicable within administrative units for better application of models in decision-making [25]. Ecosystem services and natural capital are inherently spatial by nature although some services are easier to map then others. According to Costanza et al. [26] , landscape metrics quantifies physical landscape structures which themselves determine processes and functions. Landscape metrics has therefore to be considered as meaningful parameters together with the others in ES mapping and evaluation [27]. Ecosystem services evaluation and mapping are useful for assessment of landscape capacities and potentials to supply ecosystem services [10] and to adapt the management to local conditions [18] [28]. These maps are also important to assess spatial trade-offs among ES and synergies among multiple ES [27]. Because the provision of ecosystem services depends on biophysical conditions and changes over space and time due to human induced land cover, land use and climatic changes [10] [29] , the supply and demand of services may differ geographically [30]. A number of recent studies have evaluated and mapped the supply of services at global [31] , continental [32] , national [3] [33] [34] [35] or regional scales. For this reason, it is necessary to understand better where and what services are provided by a local area of land or region [30]. The most common indicators for mapping ecosystem services are land cover, soils, vegetation and nutrient related indicators. According to a review of different approaches used to model ecosystem services, regulating services were the most commonly modeled, followed by provisioning and cultural services and supporting processes [36]. Provisioning services strongly depend on the extent of managed land and the land use intensity. However, for quantification of productivity or food provision, further information, for example on soil quality or soil management, location or climatic zone, is essential to derive a valid estimation on food provision [4]. Cultural ecosystem services are less in the foreground to be put on maps, because researchers must rely on proxies for their quantification [37]. Ecosystem services models can vary from simple expert based scoring systems to complex ecological models cycles of carbon, nitrogen and water [27]. Linking ecosystem services models to landscape coverage is one of the conditions for using these models to monitor changes in land use management, spatial planning, and implementation of the assessment of the potential of natural capital services in socio-economic planning within the region and landscape [17]. Burghard and Maes [27] highlights the importance of the process of mapping ecosystem services that can be used to visualise impacts which are often considered invisible externalities of agriculture, both positive and negative.

The aim of this study was to assess and map agroecosystem services on national level and to evaluate agroecosystem services along the climatic gradient in Slovak Republic. The paper aims to describe the use of GIS techniques in creating a uniform spatial unit for agroecosystem services inventory and compare the spatial configuration, synergies and trade-offs of agroecosystem services along the climatic regions.

Evaluation of agroecosystem services linked to spatial visualization allows to optimize the management of agroecosystems, thereby to promote synergies between ecosystem functioning and the social dynamics of respective region. Explicit modelling of agroecosystem services is considered to be one of the main requirements for implementation of the concept of these services in institutional decision-making. Krkoška, Lorenzová et al. [52] and Kanianska et al. [53] identified land use and land cover as a major driving force leading to the differencies in agroecosystem services potential. Another important driving force affecting the distribution of agroecosystem services is climatic region [54] , that impacts distribution of these services as well as interaction between them [55] [56] [57]. The correlations between climatic region categories and agroecosystem services for arable land and grassland in the Slovak Republic shows in Table 2.

Significance labels: ***p < 0.001, **p < 0.01, *p < 0.05, ns: non significant.

Positive correlation coefficient indicates the positive effect of cold climate zone, while negative coefficient indicates the positive influence of warm climate zone. The warm and dry lowland region has higher production potential, water regime regulation, pollutant filtration, and soil drainage in comparison to slightly warm to cool regions. These results are consistent with the place of occurence of soil, its properties, processes and functions in the concept of agroecosystem services [8] [20] [53].

The potential of the provisioning service of agricultural land is determined by its location in the landscape with the climatic conditions (temperature and precipitation) and it is a combination of abiotic, biotic, morphological and socio-economic factors (Figure 2). In Slovakia 29.14% of ecosystems of agricultural land has very high potential for provisioning services. They are mainly ecosystems of arable land, located in warm climate in the Danube basin. The high level of provisioning services (crop poroduction) indicates Spake et al. [58] in his work for widest lowland valleys in North Alps, where agricultural areas are overrepresented. The main limiting features of low potential of provisioning services are relatively cool climate and considerable sloppiness, limited depth or relatively high stoniness of soils in such ecosystem. In this category the predominant ecosystems are permanent grasslands. Our results show that the proportion of the category with higher potential of the provisioning service increases from the cool climate to very warm (Figure 2) (for arable land from cool climate with prevailing low potential to very warm with very high potential, for grassland from cool climate with lowpotential to very warm with high potential of provisioning services).

In Slovakia 27.47% of the area of agricultural ecosystems has very high potential for regulation of water regime (accumulation of water in the soil) (Figure 3).

They are mostly ecosystems of arable land located in Eastern Slovak Lowland, Danubian Upland, South-Slovak Basin and Košice Basin with heavy clay loam and clayey deep soils without skeleton. In Slovakia out of the total area of agricultural land the highest proportion (35.96%) have ecosystems with high potential for regulation of water regime (Figure 3). Ecosystems with low potential for water storage occupy 21.21% and they are located on deep to moderately deep, light soils without skeleton and on moderately heavy, slightly

to moderately skeletal soils. The greatest influence on water storage potential in both ecosystems has climate, but the impact of soil texture is also significant. Potential of water regime regulation within both types of ecosystems increaces from the cooler to the warmer climate and the highest potential is most represented in areals with warm climate, where deep clay soils developed on clay sediments of former seas and lakes, as well as rivers (alluvial cones, aggradational levee) occur and are situated in the foothill parts of lowlands and in the basins [59].

Agroecosystems of arable soils have a high to very high potential for regulation of soil erosion, regulation of water erosion (92% out of the total area of arable land). Arable land is located mainly in flat areas where low risk of water erosion occurs (Figure 4). These values of soil erosion significantly correlate with the attribute of slope (r = −0.72, p = 0.0008). Another prerequisite for higher potential for regulation of water erosion on arable land is presence of deep soils, and consequently higher limit for acceptable soil loss. When considering the overall coverage of land by permanent grassland (land registered in LPIS as permanent grasslands), the potential for soil erosion control achieves very high levels (total area of permanent grasslands―100%, is classified to the category with the very high potential) [8]. The potential to regulate soiltransport is increasing with warmer climate in case of arable land as well as permanent grassland. This is related to the occurrence of deep soils in lowland areas, where warm and very warm climatic regions predominate, and the limit for acceptable loss of soil is higher. In case of arable soils, there is a potential for regulation of soil erosion at approximately the same level in moderate cool (MC) and moderate warm (MW) climatic zone (Figure 4). In general, grassland potential to regulate soiltransport rises from the MC climatic zone to the VW climatic zone. The grassland potential is over 80% in the VW climatic zone (Figure 4).

Cleaning potential of ecosystems in agricultural land depends on the potential for contamination and potential of soil sorbents with high affinity to inorganic pollutants. Out of the total agriculrural land in Slovakia, 41.67% of ecosystems have very high potential for soil cleaning (immobilization of inorganic pollutants). They are mainly ecosystems of arable land with high carbonate content developed on loess, located in the Danube and the Eastern Slovak Lowlands without any anthropogenic and geochemical depositions (Figure 5). This is based on agrosystems with optimal soil parameters in relation to the ecosystem filtration service [21] [60] [61] [62]. Ecosystems of arable land of low potential (41.12% of the area) are developed on fluvisols (along Váh River, Hron River and Bodrog River). Low cleaning potential of these ecosystems is due to a higher number of risk elements in alluvial sediments, anthropogenic deposition and low potential of soil sorbents (low pH, low content of carbonates, and low content of organic matter of lower quality). However, grassland ecosystems are also strongly involved in low category of cleaning potential. Permanent grasslands mostly use farmland ecosystems located at higher altitudes as well as steeper slopes, on soils with lower sorption potential, and on soils developed on substrates with higher content of risk elements. Areas occuring in moderately cold to moderately warm climatic regions, with steeper slopes, and a higher percentage of clay particles have very low and low potentials. Very warm climatic region, mild slope and medium content of clay fraction prevail in areas with high and very high filtration potential.

Carbon stored in ecosystems is an important indicator of regulation services potential [34] whose amount depends on land use and land management practices [52]. In agroecosystems of agricultural land, soil organic matter represents the largest share of the total soil organic carbon stock. Agroecosystems contribute to climate regulation by organic carbon sequestration in soil. Soil organic carbon content can be used to represent the carbon sequestration and can be used as an indicator in climate regulation potential service [12]. The results of percentage distribution of various categories of potential of climate regulations are significantly influenced by the ecosystems of arable land due to high share of area of these ecosystems in the total area of agricultural land. Out of the total area of agroecosystems for agricultural land up to 94.83% belong to the category of low potential of climate regulations (Figure 6). Agroecosystems of arable land located in lowlands are characterized by low potential for climate regulation and low average stocks of soil organic carbon. In higher altitudes, the average organic carbon stocks, and thus the potential of climate regulation is slightly rising.

The low potential of climate control for agroecosystems of arable soils is mentioned in Burghard et al. [63] work. The average stock of soil organic matter in arable land of Slovakia (at a depth 0 - 30 cm) ranges from 59 t C ha⁻¹ (soils in altitudes from 0 to 300 m a.s.l.) to 67 t C ha⁻¹ [64]. Carbon sequestration in arable soils is lower compared to the grassland [50] within the same soil type, therefore, in case of agroecosystems of arable soils there are no categories of high and very high potential of climate control. Cambel and Souster [65] and Schnitzer [66] report that intensive soil management reduces the amount of organic matter in the soil [66]. The average stock of soil organic matter in ecosystems of slovakian grasslands (0 - 30 cm deep) is ranging from 73 t C ha⁻¹ (soil at altitudes from 0 to 300 m nm) to 86 t C ha⁻¹ (land at an altitude above 600 m a. s. l.) [64]. The high and very high category of climate regulation is up to 58.04% of the agricultural grasslands area. In case of grassland ecosystems, cambisols, which are the most widespread soil’s type in Slovakia [67] , are dominant soil type at higher altitudes (>300 m nm). Higher representation of the high category of climate control was also established in warm climatic zone (Figure 6). At elevated average temperatures, soil organic matter stock in arable soils decreased, as organic carbon inputs of plant residues and manure are not able to eliminate carbon losses due to faster mineralization [50] [68]. Agroecosystems of arable soils in colder regions have a higher potential for climate control.

Agroecosystems also have the potential for providing cultural ecosystem services, particularly recreational activities linked to natural resources, such as hiking, biking, cross-country skiing. The capacity of ecosystems to provide recreational services depends on particular uniqueness of the site, its accessibility and the surrounding infrastructure. Agroecosystems of arable land are predominantly of very low to low potential of natural conditions for recreation. In Slovakia 53.82% of permanent grassland area has high and very high natural conditions potential for outdoor recreation. On the contrary to ecosystems of arable land, grassland agroecosystems are located close to the protected Natura 2000 sites in areas with steeper sloppiness and at higher altitude. Agroecosystems have predominantly very low to low potential of natural preconditions for recreation (Figure 7). The perception of the landscape in intensively and extensively farmed areas is also different, which, according to Martens [69] , may negatively affect the attractiveness of intensive agricultural regions for recreation. The overall assessment of the potential of natural preconditions for recreation in % of agricultural land is strongly influenced by the ecosystem of arable soils (Figure 7), which has higher share in total area of evaluated agroecosystems. According to Burkhard et al. [63] , agricultural use of grassland has predominantly medium potential to provide recreational services (outdoor activities).

Trade offs and Synergies between Agroecosystem Services

Ecosystem services are non-lineary linked and changes in one service can impact the others in positive or negative way [58] [70] [71]. Spake et al. [71] define synergies when multiple services are enhanced simultaneously and trade-offs when the provision of one service is reduced due to increased use of another service. For identifying and mapping agroecosystem services associations with regards to known land use (arable land or grassland), climatic zone PCA analysis and Spearmans pairwise correlation analysis were used to evaluate the relationships between ecosystem services [58] [72].

The first axis (Figure 8) of principal component analysis biplot for agroecosystem services of arable land represents a spatial trade-offs between climatic zones and provisioning services, regulation of water regime, pollutants filtration and regulation of soil erosion. The second axis PC2 describese a synergy between climatic zones and clima regulation and their trade-offs with potential of natural conditions for recreation. The first two components accounted for 70% of the total variation in agroecosystem services. The trade-offs between climatic zones and provisioning services and regulation of water regime are more pronounced in the case of grassland.

Positively correlated agroecosystem services are assumed to be synergistic, while negative correlations infer trade-offs [58] [73] [74]. The relationship of individual services expressed through correlation coefficients is given in Table 3.

In the case of arable land trade-offs between the potential provisioning services and potential of climate regulation as well as potential of natural conditions for recreation was determined. The synergistic effect is between the provisioning agroecosystem service, regulation of water regime and soil cleaning (immobilization of inorganic pollutants). The similar relationships have been established for permanent grassland. However, in this land use management, there was no trade-offs between the potential provisioning services and potential of climate regulation as well as potential of natural conditions for recreation. The synergistic effect of regulation of water regime and soil state in its work Lescourret et al. [73]. Statistically significant synergistic effects are determined within each climatic area. Synergistic relationship between the potencial of erosion regulation and the potencial of water regime regulation as well as provisioning services has been established in all climatic regions. Only in moderate warm and very warm climatic region we have determined synergistic relationship between the potencial of provisioning services and the potencial of soil cleaning (immobilization of inorganic pollutants). In the moderate warm climate zone and warm climate zone, the potencial of provisioning services and the potencial of water regulation are also mutually beneficial.

Significance labels: ***p < 0.001, **p < 0.01, *p < 0.05, ns: non significant.

This study applies a first assessment of agroecosystem services in the Slovak Republic and allows us to link the analysis of land use and differences of particular agroecosystem services in climatic regions. Evaluation of agroecosystem services linked to spatial visualization allows to optimize the management of agroecosystems, and thereby to promote synergies between ecosystem functioning and the social dynamics of the region. Provisioning, regulating and cultural ecosystem services of agricultural land are analyzed, modelled and evaluated in spatial grid scheme, which is replicable and could be applied by planners in case that they are proficient in geographical information systems. This proposed mapping system can also be used to assess agro ecosystem services in the regions and districts in the Slovak Republic that provide guidelines and limits for policy development on land management and land use changes at local and regional levels. Applying the agroecosystem service concept can help to show the effects of land use, climatic conditions as well as human interventions by qualitatively and quantitatively analyzing trade-offs between different services and by supporting the development of site-specific, more sustainable land use strategies. According to Burghard et al. 2013 and Krkoška, Lorencova et al. (2016), the mainstreaming of agroecosystem services into national policy and decision making needs to be futher supported by assessments based on local or national data and more accurate modelling approaches.

This study suggests that climate has the most significant impact on agroecosystem services. Warm, dry lowland region has a higher potential of provisioning services, regulation of water regime, filtration of pollutants and control of soil erosion in comparison to moderately warm and cold regions. In moderate cold region, more than 90% of the total arable land area has low potential for regulation water regime and cleaning potential (immobilization of risk elements). In moderate warm climatic region, there is a high share of categories of low and moderate potential of provisioning services and low and moderate potential of regulation of water regime. Majority of the total area of warm climatic region belongs to the categories of moderate to high potential of provisioning services and high potential of regulation of water regime. In this climatic zone categories of low potential of risk elements immobilization is present in more than 65% of the total arable land area. On the other hand, in very warm climatic zone, more than 89% of the total arable land area belongs to the category with very high cleaning potential (immobilization of risk elements). Potential of natural conditions for recreation is higher only in moderate cold and moderate warm climatic zones with higher proportion of grassland area agroecosystems and protected areas NATURA 2000.

Ecosystem services are non-lineary linked and changes in one service can impact the other in positive or negative way. High potential of provisioning service is linked to the high potential of regulation of water regime, pollutants filtration and soil erosion. The opposite trend has the potential provisioning services to potential of natural conditions for recreation. However, increasing of primary and secondary production of agroecosystems must be managed with regard to the sustainability of soil multifunctionality and also the sustainability of potential of agroecosystem to provide ecosystem services in their integrity. Agroecosystems management should always be oriented to the optimization of providing of the current needs within the sustainable use of agroecosystems.

The authors acknowledge the Slovak Research and Development Agency for the financial support via Project No. APVV-0098-12 “Analysis, modelling and evaluation of agroecosystem services” amd Project No. APVV-15-0160 “Elimination of degradation processes in soil by biodiversity restoring”.

The authors declare no conflicts of interest regarding the publication of this paper.

Makovníková, J., Pálka, B., Širá?, M., Houšková, B., Kanianska, R. and Kizeková, M. (2018) Ecosystem Services in Differently Used Agroecosystems along a Climatic Gradient in Slovakia. Open Journal of Ecology, 8, 623-645. https://doi.org/10.4236/oje.2018.812037