Faunistic and landscape indicators and its usefulness for estimation of sustainable development of rural landscape (on example of chosen area)

The research project is related to usefulness of various methods of environment state indication. Our proposal is on one hand in line with a number of the indication studies, but on the other hand, it represents a new approach to system research of rural landscape, combining different indicators. The selected animal groups are Carabidae and Lumbricidae and these groups are known as good indicators of habitat and landscape changes, quickly reacting to environmental disturbances. Their response on stress is measurable quantitatively and qualitatively. Furthemore, they fulfill formal criteria of good bioindicator because they are legible and easy to apply which constitute the principles of their use in investigations. The chosen taxa differ in habitat association and dispersion ability - Lumbricidae are closely related to the soils as contrasted with more mobile Carabidae. As a result, responses to disturbances may get reflect in several ways with distinct intensity or can display sensitivity to other factors.

Diverting traditionally managed fields to large area monocultural cause landscape structure simplification and decreasing quality of ecosystems. This is directly connected with elimination or range suppression of the natural and semi-natural ecosystems (e.g. small woods and forest islands in mid-field, hedgerows, balks, marshland and peat-bogs). Consequently, it brings a loss of species related to marginal habitats - places of shelter, overwintering and breeding (e.g. Carabidae) and those directly depended on soil condition (e.g. Lumbricidae). 

The questions taken under consideration may be regarded bidirectional as (a) possibility of estimation of rural landscape state, as well as (b) problem of credibility, comparability and range of application of chosen methods of bioindication. The cognitive aim was rural landscape evaluation by means of selected groups of invertebrate as indicators against a background of habitats condition diversity, land use and landscape structure. 

The practical purpose of the project was to develop simple and inexpensive methods of identification and estimation habitats condition in rural landscapes. The fallowing research hypothesis were accepted:

1. Diversity of species and qualitative characteristic of assemblages (Lumbricidae and Carabidae) in rural landscapes depend on region, season of the year, local differentiation of landscape structure and farming practices.
2. Large area farming decrease surface diversity of vegetation, species richness, ecological variety and other characteristics of selected invertebrates taxa.
3. Geographical, ecological and anthropogenic factors can have different and specific influence, depending on chosen group of invertebrate.

The research was based on the following data: (1) cartographic materials: topographical and thematic maps, aerial photographs, (2) floristic, faunal and soil samples collected during fieldwork and analysed in laboratory, (3) documents and specialist literature.

The following methods were used:

A. Field studies 

• identification of plant communities,
• collecting Carabidae and Lumbricidae,
• collecting samples of soils.

B. Laboratory analyses:

• physical and chemical analyses of soils - current moisture [%], pH in water, electrical conductivity, organic carbon by Tyurin’s method, total nitrogen by Kjeldahl’s method, total phosphorus by Bleck method, modified by Gebhardt,
• preservation and identification of animal species.

C. Desk analyses:

• cartographic analysis,
• aerial photos’ interpretation,
• analysis and creation of digital maps,
• (geo)statistical analysis of fieldwork and laboratory results,
• indicators: faunistic (quantitative and qualitative composition, structure), soil (direct indicators) and landscape (composition and configuration metrics),
• formulation of biodiversity patterns of different sized fields.

The study areas are located in the regions of northern Poland: municipality Dubeninki and Przerośl (Lithuanian Lake District) and Potęgowo (Koszalin Sea-coast). Six research transects intersecting each region - three cross large area fields have been under intensive cultivation in many decades (previously belong to State Farms - Polish: PGR), and three cutting fields were managed in rather traditional way. Transects varied in terms of the degree of landscape fragmentation, fields size, intensity of agriculture practices and history of land use.

Carabidae beetles (about 500 pitfall traps on year) were captured using modified pitfall traps (Barber˙s traps) sank into the ground at each selected position within the transects and left for 48 hours. The contents of traps were placed into container with preservative fluid and label with the position and date. Lumbricidae (about 220 sites on year) were collected according to standard methods with mechanical collection (hand digging without using toxic substances). Soil samples 25 x 25 x 25 cm deep were taken from each plot and sieved (this time-consuming but effective method allows to gain individuals <0,01 g). Earthworms were also preserved and labelled. Collection sites were the same at each season and covered with places of soil samples. Both taxa were collected during spring and autumn season 2007/2008. Further quantitative and qualitative characteristics: identification of species (Hůrka 1996; Müller-Motzfeld 2004; Plisko 1973; Kasprzak 1986); determination of their biomass/body length. Then Carabidae were classified according to the following criteria: (1) trophic, (2) environmental, (3) level of develop, (4) preference for habitat humidity and (5) zoogeographical (Burakowski et al. 1973, 1974; Leśniak 1987; Lindroth 1992; Hůrka 1996; Aleksandrowicz 2004; Müller-Motzfeld 2004). Lumbricidae were classified to ecological groups (Bouché 1972), age structure, domination structure and association with biocoenosis.

Lumbricidae i Carabidae can be used to asses land use and degree of sustainability of rural landscape. Nevertheless, their use for purposes of monitoring requires methodical discipline. Comparison between regions needs testing within the same time and type of spatial arrangement. Confronting spring season with autumn in one area only show us changes arising as a result of intra-population or climate factors. Comparing of spring seasons also does not have substantiation, as differences may be of intra-regional character, rather than distinctions of complex of field in land use. 

Both, conducted studies and analyses, and resulting conclusions fit well in the assumptions of theoretical concepts concerning the relationship between land use and spatial and functional structure of landscape. The first is the concept of ecologically sustainable landscape, as a condition for sustainable development in rural areas, while the second is the concept of optimal landscape structure.

The statistical analysis were performed using the programs: Statistica 7.0, SAS 9.2, Past 2.03 (Hammer et al. 2001). Similarity of Lumbricidae community were define by cluster analysis using arithmetic averages (UPGMA) based on Bray-Curtis (quantitative data) and according to Kulczynski’s formula (qualitative data). As the measure of Carabidae assembly similarity Ward method and Euclidean distance was performed. In order to determine the significance of differences between the quantitative characteristics of chosen groups of animals multifactorial analysis of variance (ANOVA), with the level of significance (p = 0.05) were conducted.

The significance of these differences between numbers of particular of Lumbricidae species and physically-chemical soil characteristics were analysed by the analysis of co-variance (ANCOVA) forming part of GLM (General linear model – SAS 9.2). 

The quantative and qualitative ecological characteristic of Carabidae and Lumbricidae assemblages were described on the basis of the total abundance and biomass (body length) of species, the total number ecological groups and Renyi's diversity index.

The patterns of group differentiation both spatial and time were analysed (regional, habitable and seasonal similarities or dissimilarities). Relations between species’ richness, ecological diversity, abundance of selected taxa and variety of habitat conditions, landscape structure and rural land use were defined. It was determined which of indicators used are complementary, which present exert similar patterns of change and which one display particular distinction.