Browsing by Subject "Management intensity"

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    Functional larval-parasitoid biodiversity in apple orchards as benchmark for management intensity and potential instrument for ecological amelioration of Iranian apple production
    (2019) Lashkari-Bod, Abdullah; Zebitz, Claus P. W.
    Although a consensus through the concept of sustainable agricultural production and its indicators to assess its functionality varies, it is expected to be long-term and reliable. The sustainability would change temporarily and spatially. It is influenced by political, social and economical is-sues, which reveals its interdisciplinary essence in concert with farming strategies and practices to produce human food. The management of plant protection is capable to impose unsustainability into farming system. The frequency and intensity of unsustainable practices would result into devastating effects on diversity and abundance of beneficial arthropods. The communities of natural enemy may promote sustainable management, but the anthropogenic interventions such as broad-spectrum pesticide applications would distort the essence of self-monitoring of natural invertebrates as regulators. The conventional agricultural management makes the habitats to be simplified through food webs and ecological complexities, which lead to species loss (extinction or emigration) and consequently to species interactions (connectance). The ecologically based management such as integrated pest management (IPM) would focus to maintain species and increase diversity in natural communities, which contributes to sustainable approach as alternative versus conventional agriculture. The negative effects of chemical pesticides would dramatically decline the ecosystem process and affect the energy flow among different trophic levels, which is manifested as functional rates in local or regional scale of ecosystem. The human-manipulated areas create negative consequences on the ecosystem functionality through vanishing the key natural resources (i.e. shelter, food provision, and alternative host prey), which affect maintaining natural enemy communities. The complementarity effects of antagonist communities can lead a synergetic impact on pest control, when biodiversity is conserved through vegetation, rational bio-pesticide application, and ecological infrastructure, the functional traits (richness and evenness) among interacting species will be improved. Furthermore, the intensified agriculture would arise pest outbreaks or convert a secondary and unimportant pest into a serious one. The antagonistic communities may represent as bio-indicators. The presence or absence of higher trophic levels and their complexes would reflect biotic or abiotic changes in the environment, which would eventually be expressed as parasitism or consumption rate. The scope of current research is limited to indicators of sustainability through pest management and does not comply a holistic approach on ecological, political, social, and economical managements. The preliminary results focus on the status quo of plant protection in Iran and biodiversity indices in Germany used to compare the different farm systems to show how the management can affect the community components and their interactions. The environmental and anthropogenic impacts on biodiversity of beneficial arthropods in different orchard management conducted in Germany, where the accessibility of abandoned apple orchards is more prevalent than Iran. To evaluate the impact of conventional intensive management vs. ecologically based sustainable practices on invertebrate beneficial community, a comparative study was conducted to assess food web pattern of larval-parasitoid communities, biodiversity indices, and parasitism rate in response to apple orchard by four different managements. Field samplings were occurred during 2011-2015 in Baden-Württemberg, Germany. The orchard managements were distinguished based on the frequency and intensity of pesticide applications into the farming system. The categories of orchard management were managed (organic and integrated), and Streuobst (semi-abandoned orchard), which were situated in Denzlingen, Emmendingen, Goldener Grund, Hohenheim research center, Ilsfeld, Lake Constance, Neuhausen, Plieningen, Rommelshausen, and Scharnhausen. The sampling was conducted by installation of corrugated cardboard and random observation to collect larval caterpillars (Tortricidae and Gelechiidae). The collected samples were transferred to lab to rear adult parasitoids and further studies on taxonomic affiliation. Out of 7,923 healthy host larvae collected, totally 324 parasitoid individuals from three sub-families of Braconidae, Ichneumonidae, and Perilampidae were found. Four parasitoid species were found positive host-density dependent, the rest of the parasitoid species showed no densi-ty-dependency or were found in too small numbers. The highest richness, abundance, and evenness of larval-parasitoids were found in Streuobst orchards (i.g. Plieningen), which received no to minimal pesticide inputs. The interaction diversity of food webs (connectance) in Streuobst showed the highest number of trophic links in response to other orchard managements where the commercial (conventional) orchards harbor no to the least biodiversity indices of beneficial arthropods. Percentage similarity also assessed to depict the similarity of larval-parasitoid community structures in different managements. It was revealed the orchards with the same management contain similar parasitoid compositions. To describe and analyze the information on apple growing management, circumstances of plant protection, pest status, and major obstacles to initialize sustainable production in Iran, a questionnaire was designed to survey 39 apple growers from East-Azerbaijan, Fars, Isfahan, Tehran, and W. Azerbaijan in July 2014. It was found that management of the orchards mostly is under the supervision of the apple growers. Farmers in Isfahan suffer a road infrastructure to have an access to the nearest market to sell their product indicating an economic monopoly. The distance to experts affects the intensity of pesticide application by farmers. The conventional agriculture is prevailing in all provinces and access to bio-pesticides highly limited to Tehran. Totally 29 pesticides were used against different fruit pests in Iran. The most damage intensities occurred by pests in province scale and weeds in regional scale. The outbreak of secondary pest Tetranychus urticae as key one indicates human perturbations in Iran’s farming system. Tehran province enjoyed diverse apple cultivars contrary to other provinces, which are poor in diversification. The predominant outlook to choose a cultivar among apple growers was marketing.