**3. Results**

#### *3.1. Habitat Map with Á NÉR Categories*

Based on the field works, 19 habitat types (i.e., Á NÉR categories) and their combinations (habitat complexes) were identified, resulting in a total of 29 patch types in the map. Table 2 summarizes the size and the number of the identified habitat patches.


**Table 2.** The number and the size of the habitat patches identified in the study area.

#### *3.2. Habitat Types of the Study Area*

According to the habitat map (Figure 2), mosaics of gallery forests (J4) and swamp meadows (B1a, B2, B5) are common in the north-eastern edge of the area. Wet meadows are also common due to the water supply. Figure 3 shows the vegetation belt in the foreground of the gallery forest. It is seemingly continuous and its parts are di fficult to distinguish during habitat mapping. From the narrow belt of the gallery forest (Figure 3A1) the following plant associations appear: *Phragmitetum vulgaris* Soó 1927, *Scirpetum lacustris* Chouard 1924, *Typhetum angustifoliae* Pignatti 1953, *Typhetum latifoliae* Lang 1973, *Sparganietum erecti* Roll 1938. In the wetter part (Figure 3A2), swamp meadows and *Carex*-dominanted associations appear as a complex, with patches of di fferent sizes: *Caricetum gracilis Almquist* 1929, *Caricetum vesicariae* Chouard 1924, *Galio palustris-Caricetum ripariae* Bal.-Tul.et al.1993, *Caricetum vulpine* Soó 1927, *Caricetum melanostachyae*

Baláž 1943, *Caricetum distichae* Jonas 1933, and in some places even the *Phalaridetum arundinaceae* Libbert 1931, *Oenantho aquaticae-Rorippetum amphibiae* R.Tx.1953 and the *Butometum umbellati* Philippi 1973. In this belt, *Lychnis flos-cuculi* L. (Figure 3B) and *Ranunculus* ssp. are also dominant in the spring aspect.

**Figure 2.** Habitat map of the Dejtár area using ÁNÉR categories.

**Figure 3.** Lower seated area of the Ipoly Valley. (**A1**): Gallery forest along the Ipoly; (**A2**): Swamp meadow dominated by *Carex* spp. (**B**): In the belt area in the Ipoly Valley, *Lychnis flos-cuculi* and *Ranunculus* ssp. are in the spring aspect.

On higher elevations, sandy grassland and shrubby, woody patches appear (Figure 4A). The number of patches of sand steppe meadows (H5b) was the highest (16 pieces) and its total area was also large

(63.4 ha). However, considering the associations, they are less continuous than wet patches, because the drier parts of the higher elevations were dominated by *Stipa borysthenica*, which is an element of *Festucion vaginatae* Simon 2000.

**Figure 4.** (**A**) Sandy grasslands and shrubs appearing in the higher seated parts. (**B**) *Salvia pratensis*, a dominant steppe species. (**C**) *Stipa borysthenica*, a dominant steppe meadow grass species.

In contrast, *Festuca vaginata* W. et K., an important characteristic species of open sandy grasslands is missing and the frequent occurrences of *Salvia pratensis* L. (Lamiaceae) are a sign of the steppe character and causes the vegetation to be akin to *Salvio-nemorosae-Festucetosum rupicolae* Zólyomi ex Soó 1964. From a coenological perspective, it is an interesting situation when a loess-steppe vegetation appears on sandy soil, with *Festuca rupicola* and *Salvia pratensis* as the dominant species (Figure 4B). *Thymus* spp., *Dianthus pontederae* A. Kern. and *Koeleria cristata* (Ledeb.) Schult., which are steppe elements, are also found here. Similarly to the original acidic Pannon sandy grasslands, *Pulsatilla pratensis* ssp. *nigricans* also appears. This vegetation type is very close to *Potentillo arenariae-Festucetum pseudovinae* Soó 1938, 1940, which is a rare association in the eastern part of the Pannonian region, as many of its species appear here.

Furthermore, in the most nutrient-poor parts of the area, diversity of the vegetation of sandy hedges is expanded by *Thymo serpylli-Festucetum pseudovinae* Borhidi 1958 as a new occurrence in the Pannon region. This association was known only from the eastern part of the Pannonian region (Nyírség), and was described in southwestern Hungary (Inner Somogy). Its important characteristic species is *Corynephorus canescens* (L.) P.Beauv. On sandy plains, these habitat patches appear along with pioneer arid and semiarid

woody associations (P2b) as a mosaic. This vegetation forms after deforestation or as a consequence of heavy grazing.

#### *3.3. NDVI versus Á NÉR Categories*

Lower vegetation productivity results in lower NDVI value [27]. In the study area (Figure 5), the lowest NDVI value was 0.076 while the highest was 0.83. Urban areas and water bodies have the lowest values, near 0. Still waters ( Á NÉR category: U9) have NDVI values between 0.08 and 0.55. The positive values can be explained by the biological activity in the water but the level of reflection is very low due the chlorophyll-poor areas [30]. Intensively cultivated farmlands (T1) have similar values. The category of roads and railroads (U11) showed low NDVI values similarly to the previous Á NÉR categories due to the low biological activity; therefore, this category is well separated from the other classes. Swamp meadows (D34) on lower elevations along the river are more unified, while the reefs are distinctly di fferent, which means that the di fferences originating from the elevation can also be observed in the vegetation of the area. NDVI values are higher where plant activity is higher, or the phenological phase of the plant is in the growing period. More arid sand associations showed low NDVI (0.56–0.632). Most sandy steppe meadows (H5b) along with transitional habitats between grasslands and woody patches had values of 0.632–0.666. Swamp meadow vegetation (D34) is clearly distinguishable from *Saliceto-Populetum* Meijer-Drees 1936 (J4) and dry-semi-dry pioneer shrubs (P2b) complexes along the Ipoly. Woody vegetation did not appear to be very unified, while NDVI categories di ffered depending on the phenological phase.

Figure 6 shows the di fferent NDVI values of randomly chosen 20 pixels from each Á NÉR category. Results of the statistical comparison of mean NDVI values among the habitat types are summarized in Table 3. Water bodies (U9) urban areas, such as fallow lands (T1) sand mines (U7), and roads (U11) di ffered significantly from the majority of other habitats. A somewhat higher but still low NDVI value was found in the sandy steppe meadows (H5b). Woody and grassland vegetation di ffered from each other. Categories of grassland vegetation, such as sandy steppe meadows (H5b), uncharacteristic arid and semiarid grassland complexes (OC), and uncharacteristic fresh grasslands (OB) showed lower NDVI values. In contrast, woody vegetation patches, such as riverine willow shrubs (J3), planted pinewoods (S4), and Riverine willow-poplar woodlands (J4) significantly di ffered from most of the non-woody habitats. Dry shrub vegetation with *Crataegus monogyna*, *Prunus spinosa* L. and *Juniperus communis* L. (P2b) showed uniformly medium high values. Wetter and arid grasslands, which are important in terms of grassland farming, di ffered greatly. Dry grasslands were not uniform because of the species characteristic in them, while in dry grasslands the cover of *Corinephorus canescens* (L.) P.Beauv., *Festuca psedovina* Hack., *Festuca ovina*, *Festuca rupicola*, and *Stipa borysthenica* are larger. These species occur sporadically in the OC category.

**Figure 5.** Habitat maps of Dejtár area using ÁNÉR categories and Normalized Vegetation Index (NDVI) data.

**Figure 6.** Distribution of ÁNÉR categories (habitat patches) based on NDVI data.


**Table 3.** Statistical comparison of mean NDVI values of the characteristic habitat types in the Ipoly Valley, Hungary. (\*: *p* < 0.05, \*\*: *p* < 0.01, \*\*\*: *p* < 0.001, ns: not significant).
