Alexandra D. Solomou

Comparing conventional and organic olive groves in central Greece: plant and bird diversity and abundance

The present study was conducted in Magnesia Prefecture, central Greece, during the period May–June 2007. It aimed at the comparison between conventional and certified organic olive groves with regard to olive and olive oil production, diversity of plants (herbaceous and woody) and diversity and abundance of avifauna. Correlations between variables within herbaceous plants (linear regression) and woody plants (Principal Component Analysis), and the role of integration time of olive groves to the organic system were investigated. Also, finding easily measurable parameters indicating high bird diversity levels within organic and conventional management systems was a main target of the study. According to our findings, neither edible olive yield nor olive oil yield showed significant differences between conventional and certified organic olive groves. There is an increasing trend for alpha and beta diversity of herbaceous plant species, woody plant beta diversity, density and cover of woody plants, and density of breeding birds in certified organic olive groves (10 years) in comparison with conventional ones. The effect of time since the adoption of organic procedures is very important and produces benefits for the biodiversity. In the total olive groves 15 insectivorous, six granivorous and three insectivorous/granivorous birds species were recorded. Nine bird species distinguished by Wards hierarchical clustering were identified as typical (indicator value, IndVal>50%) of specific farming systems. Among them, the Eurasian jay, associated with the 10-year certified organic olive groves, and the common cuckoo, Orphean warbler and Red-backed shrike, associated with the 6-year certified organic olive groves, should be regarded as characteristic species (IndVal>70%). Conclusively, organic farming favors some aspects of diversity of herbaceous and woody plants of olive grove ecosystems. On the contrary, similar effects on breeding bird diversity and density were not clearly recorded. However, breeding bird density proved a good indicator of their richness.

Bird community characteristics as indicators of sustainable management in olive grove ecosystems of Central Greece

The role of breeding birds as indicators of sustainable management in olive groves was investigated. The data revealed significantly higher alpha diversity in organic and abandoned olive groves and maquis than in conventional ones. The highest beta diversity was found between the following pairs: organic olive groves–maquis, and abandoned olive groves–maquis. Breeding bird diversity, Heteroptera, Hymenoptera, Hemiptera and Coleoptera densities positively influenced bird species richness in organic olive groves and maquis, and additionally, manure application positively influenced bird species richness in organic ones. Bird species richness was negatively influenced by pesticide and inorganic fertilizer application in conventional ones. Moreover, isopod density was unimportant in explaining breeding bird richness in organic olive groves. Finally, our study suggests a difference in bird communities of various olive groves as a result of different management and practices, and concludes that birds might serve as indicators of overall olive grove health. Furthermore, these findings could be used as a tool for prediction of breeding bird species richness probability in different olive grove management systems and maquis. Finally, the results of the present study may contribute to highlighting some aspects of the effect of different farming practices on the dynamics of Mediterranean bird communities.

Determinants of Woody Plant Species Richness in Abandoned Olive Grove Ecosystems and Maquis of Central Greece

The present study aimed to compare the woody plant species richness and cover (%) of five abandoned olive groves and five maquis ecosystems in central Greece and to describe the relationship between woody plant species richness and a set of environmental variables [soil pH, nitrogen (N), phosphorus (P), potassium (K), and organic matter; air temperature and humidity; altitude; slope; type of ecosystem; and presence of leaf litter]. Although woody plants are abundant in the abandoned olive groves, the number of species and amount of cover (%) are significantly greater in maquis. According to principal component analysis, woody plant species richness was positively correlated with soil organic matter, plant litter, and soil P and K in maquis. Also, woody plant species richness was positively correlated with slope in the abandoned olive groves. Olive grove ecosystems abandoned for at least 12 years have developed species compositions similar to the corresponding features of neighboring maquis, although the number of species and amount of cover (%) are significantly greater in maquis.

Effects of Organic Farming on Winter Plant Composition, Cover and Diversity in Olive Grove Ecosystems in Central Greece

The present study aimed to assess the effects of organic farming in comparison with conventional on plant composition, plant cover (%), diversity [species richness, Shannon, Simpson, and evenness (Pielous) indexes] and investigate and describe the relations among plant species richness, plant cover, indexes, and soil parameters (pH and temperature) in olive grove ecosystems during the winter. Organic olive groves had significantly greater values of cover, species richness, and Shannon and Simpson indexes than the conventional ones. Plant species richness was positively correlated to plant cover and Shannon and Simpson indexes but negatively correlated to evenness index for both farming system. Finally, plant cover was positively correlated to the Shannon and Simpson indexes for both farming systems. According to principal component analysis (PCA), for axis 1, positive correlation was detected among the plant species richness, soil temperature, and Shannon and Simpson diversity indexes, whereas for axis 2, negative correlation was detected between plant cover and soil pH. It can be concluded that the organic management system enhances herbaceous plant cover and diversity (species richness, Shannon and Simpson indexes) in olive grove ecosystems during the winter.

Species Richness and Density of Earthworms in Relation to Soil Factors in Olive Orchard Production Systems in Central Greece

Earthworms can be used as bioindicators of soil management as they are easy to classify and very sensitive to changes of both physical and chemical soil parameters. The aim of this work was to study relations between earthworm species (richness and density) and the physicochemical soil properties such as pH, organic matter, soil moisture, and texture (percentages of sand, silt, and clay) under different farming practices (organic and conventional) in olive groves in central Greece. The data revealed significantly greater values of earthworm species richness, density, soil organic matter, and moisture in the organic olive groves than in the conventional ones. Furthermore, total earthworm density was positively correlated to earthworm Shannon diversity index, soil moisture, organic matter, nitrogen, phosphorus, and potassium in organic olive groves. However, total earthworm density was negatively correlated to soil pH and silt in conventional olive groves. It can be concluded that species richness and density of earthworms in olive groves can be considered as sensitive indicators of management practices.

Herbaceous Plant Diversity and Identification of Indicator Species in Olive Groves in Central Greece

The present study is aimed at assessing the herbaceous plant diversity and determining the specific species related to different management systems in olive grove ecosystems [organic, conventional (unsprayed), and conventional (sprayed)] in two sites (Nies and Pteleos) of Magnesia Prefecture (central Greece). The sampling of herbaceous vegetation was carried out in randomly selected plots of 0.25 m2 (0.5 m × 0.5 m) each. The results showed that the organic system in Pteleos favored plant species richness and Shannon–Weiner, Simpson, Margalef, Brilluin, McIntosh, and Menhinick indexes more than the other management systems (P < 0.05). A Renyi diagram revealed the greatest plant diversity in the organic system in Pteleos site. According to cluster analysis results, the organic and the conventional (unsprayed) olive groves in Pteleos exhibited a strong similarity regarding plant diversity. The same was detected in the pairs: Nies conventional (unsprayed) and Nies organic, and in Nies conventional (sprayed) and Pteleos conventional (sprayed). IndVal analysis revealed three “characteristic” types of indices, Chenopodium album in the organic olive groves in Pteleos, Sinapis arvensis in the organic ones in Nies, and Aegilops geniculata in the conventional (unsprayed) olive groves in Nies.

Organic Farming as an Essential Tool of the Multifunctional Agriculture

This chapter aims at shedding light on the annals of organic farming and at defining its past and present meaning. Low-profile attempts were made in the first half of the last cen‐ tury when it comes to organic farming as it developed almost independently in the Ger‐ man and English speaking world. Organic farming has been established as a promising and innovative method of meeting agricultural needs and food production with respect to sustainability (climate change, food security and safety, biodiversity, rural development). Its value in terms of environmental benefits is also acknowledged. The differences be‐ tween organic and conventional food stem directly from the farming methods that were used during the food items’ production. Many people are unaware of some of the differen‐ ces between the two practices. Agriculture has a direct effect on our environment, so un‐ derstanding what goes into it is important. There are serious differences between organic and conventional farming; one of the biggest differences that is observed very frequently across all research between the two farming practices is the effect on the land. Conclusive‐ ly, organic farming is a form of agriculture that relies on ecosystem management and at‐ tempts to reduce or eliminate external agricultural inputs, especially synthetic ones. It is a holistic production management system that promotes and enhances agro-ecosystem health, including biodiversity, biological cycles, and soil biological activity.

Assessment of Greek Forests Protection and Management

Forests perform multiple and intertwined social, economic, and environmental functions. Greek forests are complex biotic communities, characterized by trees, and encompassing much of the life on Earth. Efficient forest management strategies should be formed to consider the future forest dynamics to achieve important management objectives such as biodiversity conservation preserving ecological functions and countering climate change. Greek forests have long been threatened by a variety of destructive agents. The greatest problem for Greek forests is the lack of management. In Greece, during past years, serious natural disasters have occurred, associated with fires and floods that are inextricably linked to its geographic location, geology, geomorphology, vegetation, and the prevailing climatic conditions. Hence, restoration of forest ecosystems is of great importance and a main environmental issue in Greece. Efforts of restoration are based on earlier empirical techniques, which were later improved, and supported by scientific research. The selection of a suitable method and its implementation demands deeper knowledge of natural ecosystem functions and of the physiology of diverse organisms. Moreover, a versatile, and interscientific approach is required, coordinated with the direction of the goals and objectives of the restoration, individual actions, utilization of research results, usage and improvement of technologies, as well as the creation, improvement, and development of infrastructure.

The effects of farming practices on earthworm dynamics in olive groves of central Greece

Abstract We compared species richness, species composition, density and biomass of earthworm communities in organically and conventionally managed olive groves in central Greece. Earthworm biomass and density was significantly higher (p<0.05) in organic olive groves than in conventional olive groves. The highest species richness was recorded in the organic olive groves. Six species were recorded in total: Octodrilus complanatus, O. croaticus, Dendrobaena byblica, D. veneta, Aporrectodea caliginosa, and Microscolex phosphoreus. Only four of these were found in conventional olive groves, where D. veneta and M. phosphoreus were absent. The most abundant species were O. complanatus, D. veneta, and D. byblica.