The land use and land cover pattern of landscapes are key elements of basic landscape structure; accordingly, this pattern has an important role in landscape management, nature conservation and preservation. In the other hand the human impact on the ecological environment has attracted a significant amount of attention. In this study, hemeroby index (HI) was used to quantify the degree of human disturbance, and the relationship between HI and landscape pattern metrics was explored in a region of Central Portugal. The main objectives of this study were to analyze the temporal and spatial characteristics of landscape pattern, and its relationship with different degrees of human disturbance. The Spearman's correlations were determined to reveal the statistical connections between the landscape metric parameters and the HI values. At a landscape level the Mean Perimeter-Area Ratio (MPAR) showed a significant statistical connection with the HI. At a class level most of the metrics can be used to estimate the spatial changes of the hemeroby level, with Mean Patch Size (MPS) and Mean Perimeter-Area Ratio (MPAR) showing significant statistical connection with the hemeroby index, for agricultural areas, pastures and seminatural areas. Landscape pattern, human disturbance, land use cover change, GIS
Exploring the impact of human activities on the landscape pattern is an increasing concern, and
monitoring and evaluating human interference has become one of the hotspots and important areas of
landscape ecology research [
According to the pattern and process paradigm, the land cover pattern predicts the ecological
processes occurring in a given landscape [
The hemeroby index is an integrated indicator used in several studies (e.g., [
The study aimed to investigate the relation between human disturbance intensity and landscape pattern configuration and diversity. The objectives of this study are (1) to analyze the temporal and spatial characteristics of landscape pattern and human disturbance in the process of land use change in mainly rural territories, and (2) to explore the relationship between the landscape pattern metrics and the human disturbance under different disturbance intensities, in order to reveal how landscape-patternchange tendencies can be used as indicators to estimate the anthropic changes in the landscape.
2022 Copyright for this paper by its authors.
The Beira Interior region is an administrative division in eastern Portugal that includes two main subregions: Beira Baixa and Beiras/Serra da Estrela (Fig. 1). The region covers an area of 10919 km² and has a population of 325086 inhabitants. It has elevations ranging from 47 to 1993 m. This territory is mainly occupied by forest, agroforestry uses and agricultural land.
The Portuguese Land Use/Land Cover (LULC) databases (COS 1995; COS 2007; and COS 2018) were applied to calculate the landscape metrics. Patch level and landscape level metrics were calculated for 121 quadrats of 10 km2 each, covering the study area, with the Patch Analyst extension of the Arc GIS 10.8 software.
The LULC classes were categorized in a scale of hemeroby levels ranging from ahemerobic (no
anthropogenic influence) to metahemerobic (biocenosis completely destroyed). For that purpose, a
seven-point scale was used to classify land use according to the degree of hemeroby by modifying [
Landscape configuration was quantified through a set of metrics. Statistics describing the
distribution of patch area such as Mean Patch Size (MPS) were computed as they provide central
tendency. Mean Shape Index (MSI) provides indications of the fragmentation degree of the different
land cover types. Total Edge (TE) includes all landscape boundary and background edge segments.
Mean Patch Fractal Dimension (MPFD) and Mean Perimeter-Area Ratio (MPAR) describe landscape
complexity [
We revealed the statistical connections between landscape metrics and hemeroby index value for all
10 km2 quadrates of the Beira Interior region on a landscape level with IBM SPSS Statistics 22 software.
The distribution of the variables was analyzed with the Shapiro-Wilk test, but most variables did not
follow the normal distribution; therefore, we applied the non-parametric Spearman rank correlation
coefficient [
In Figure 2 are presented the LULC maps for the three years (1995, 2007 and 2018), and changes in surface area of the LULC classes between 1995 and 2018. The main land use classes in the study area are cultivated land and forest land.
During the study period the cultivation of arable lands and the pasture area decreased in the last decades, and this abandonment induced an increase in seminatural and forests areas (Figure 2b). a)
According to our estimations, the average hemeroby index value maintained stable during the study period: 3,65 in 1995; 3,62 in 2007; and 3,64 in 2018. Corresponding to an α-euhemerobic level (moderate to strong human impacts).
As shown in Table 3, at a landscape level the index Mean Perimeter-Area Ratio (MPAR) showed a strong negative correlation with the hemeroby index (p < 0.01) in 1995, 2007 and 2018. That suggests that complex landscapes are good indicators of low levels of hemeroby. In fact, areas of more intensive agricultural and forestry use tend to occupy large areas of territory with low spatial diversity. The other metrics did not show a significant relationship with the hemeroby index.
At a class level Mean Patch Size (MPS) and Mean Perimeter-Area Ratio (MPAR) showed significant correlation with the hemeroby index, for agricultural areas, pastures and seminatural areas. *Correlation is significant at the 0.01 level.
According to the change in hemeroby index value verified between 1995 and 2018 (Figure 3), the naturalness degree increased in 60% of the quadrats and decreased in the remaining quadrats, with a clear difference between the eastern and western part of the study region. This tendency could be related to the land abandonment that induced an increase in semi-natural areas in the east part of the Beira Interior region, and an increase in the intensive monocultural forest in the west part of the region.
We can conclude that landscape metrics could be appropriate for describing the hemeroby level of the landscape and for predicting the possible changes of vegetation-based naturalness at a regional scale, confirming the results of previous studies in different countries.
At a landscape level the Mean Perimeter-Area Ratio (MPAR) showed a significant statistical connection with the hemeroby index. At a class level Mean Patch Size (MPS) and Mean PerimeterArea Ratio (MPAR) show significant statistical connection with the hemeroby index for agricultural areas, pastures and seminatural areas.
The use of a set of structural and hemeroby indicators can be useful for planners and decision-makers to analyze trends in land use patterns at a regional level and to design of new policies for reducing the anthropic impacts on ecosystems.
This work is supported with Portuguese national funds by FCT - Foundation for Science and Technology, I.P., under the project UIDB/00681/2020.