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Agroecosystem Quality: Policy and Management Challenges for New Technologies and Diversity
Abstract and Figures
Providing a meaningful contribution to the topic of agroecosystems, new technology, and diversity poses many challenges. First, it is difficult to obtain agreed-on definitions or standards for “agroecosystem quality.” The second difficulty occurs when considering how new technologies affect agroecosystem quality, including
issues related to biodiversity. These difficulties, and the management and policy issues which they raise, are illustrated by examples of technical and adaptive challenges facing agricultural policy makers, managers, and end users concerned with maintaining levels of biodiversity or enhancing agroecosystem quality.
The objectives of this chapter are to first consider the differences between these technical and adaptive problems, the nature of the situations they each address, and the learning required when facing an adaptive challenge. Second, agroecosystem complexities and the difficulties in determining quality indicators are presented.Applications of biotechnology are presented as derived from international collaborative research using examples compiled by the Intermediary Biotechnology Service.
(IBS), executed by the International Service for National Agricultural Research
(ISNAR). Some of these examples, as used in IBS policy seminars, highlight
emerging policy and management needs which were identified and discussed. It is
hoped that this chapter clarifies adaptive challenges regarding agroecosystem diver-
sity and quality, and prepares stakeholders for the challenges and opportunities of
new technologies.
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... A nivel mundial, los cambios en la forma de uso de la tierra han generado ambientes agrícolas muy simplificados en términos de biodiversidad ambiental, vegetal y animal (Ryszkowski & Jankowiak 2002). La disminución de la biodiversidad y la consecuente homogeneización del hábitat como resultado de las prácticas culturales más utilizadas por la agricultura moderna comprometen tanto la sustentabilidad como la estabilidad y la productividad futura de los ecosistemas agrícolas (Cohen 1999;Benton et al. 2003). En los agroecosistemas pampeanos se ha producido una disminución marcada de la diversidad de cultivos agrícolas, asociada al incremento de la dominancia del cultivo de soja. ...
Numerosas especies de artrópodos invernantes de la región pampeana utilizan a las gramíneas perennes como refugio. Las características estructurales y el tamaño de las plantas, así como su disposición espacial, condicionarían la disponibilidad de hábitat o de refugio y, en consecuencia, la selección de esas plantas por artrópodos invernantes. En este trabajo evaluamos la influencia del tamaño, el agrupamiento y la modificación de la arquitectura de plantas de Schizachyrium condensatum sobre la abundancia y la riqueza de artrópodos invernantes en su interior. En un borde de un área agrícola de la Pampa Ondulada se dispusieron plantas de distinto tamaño, desde 110 cm de altura (plantas grandes) a 70 cm de altura (plantas pequeñas), de manera aislada o en grupos de cinco plantas, a las que se les modificó, o no, la arquitectura (abiertas o cerradas). Luego de la temporada invernal se extrajeron los artrópodos y se determinó la abundancia y la riqueza de morfoespecies en cada planta. Dos especies depredadoras de la familia Coccinellidae, Hippodamia convergens y Coccinella ancoralis, representaron 90% de la abundancia total, y se concentraron en su mayoría en las plantas grandes agrupadas-cerradas. En las plantas grandes cerradas se registró más del doble de la abundancia de artrópodos que en las plantas grandes abiertas. En las plantas pequeñas no hubo efectos debido a la arquitectura. Se registró similar riqueza de especies de artrópodos entre plantas pequeñas aisladas y plantas pequeñas agrupadas. En las plantas grandes agrupadas se detectó casi el doble de especies de artrópodos que en las plantas grandes aisladas. Estos resultados muestran que el tamaño pequeño, así como la apertura y el aislamiento de las plantas grandes, influyen de forma negativa sobre la selección de los sitios de refugio de coccinélidos invernantes. En consecuencia, planteamos la importancia de la conservación de las gramíneas perennes en los bordes de áreas agrícolas como refugios que asegurarían la permanencia de coccinélidos afidófagos en las proximidades de los campos de cultivo durante el período invernal.
... Los cambios en la forma de uso de la tierra han generado ambientes agrícolas muy simplificados en términos de biodiversidad ambiental, vegetal y animal (Ryszkowski & Jankowiak, 2002). La disminución de la biodiversidad y la consecuente homogeinización del hábitat como resultado de las prácticas culturales más utilizadas por la agricultura moderna, comprometen la sustentabilidad, la estabilidad y la productividad futura de los ecosistemas agrícolas (Cohen, 1999;Benton et al., 2003). ...
... A nivel mundial, los cambios en la forma de uso de la tierra han generado ambientes agrícolas muy simplificados en términos de biodiversidad ambiental, vegetal y animal (Ryszkowski & Jankowiak 2002). La disminución de la biodiversidad y la consecuente homogeneización del hábitat como resultado de las prácticas culturales más utilizadas por la agricultura moderna comprometen tanto la sustentabilidad como la estabilidad y la productividad futura de los ecosistemas agrícolas (Cohen 1999;Benton et al. 2003). En los agroecosistemas pampeanos se ha producido una disminución marcada de la diversidad de cultivos agrícolas, asociada al incremento de la dominancia del cultivo de soja. ...
Perennial grasses are used as overwintering shelters by several arthropod species in the Pampa region. Plant size, structure, and clustering may condition habitat or shelter availability, and therefore their selection by overwintering arthropods. We analyzed the influence of clustering, size and architecture modification of Schizachyrium condensatum plants on the abundance and richness of these arthropods dwelling inside these plants. We set up plants of different sizes, from large (110 cm tall) to small (70 cm tall), along the edge of a field crop in the Rolling Pampas. They were planted isolated or in groups of five plants, with or without architecture modification (open or closed). After the winter season, overwintering arthropods were removed and the abundance and richness of morphospecies were calculated for each plant. Two predator species from the Coccinellidae family, Hippodamia convergens and Coccinella ancoralis, represented almost 90% of total abundance in large, grouped and closed plants. In large closed plants there was almost twice the abundance of arthropods than in large open plants. In small plants there was no effect due to architecture. In small plants there was similar arthropod richness between isolated and grouped plants, whereas in large plants there was almost twice the species in grouped than in isolated plants. Our results show that small plant size, as well as opening and isolation for large plants, negatively affected the choice of wintering sites for coccinelids. Therefore, we highlight the importance of conserving perennial grasses in the edges of agricultural areas as they allow the persistence of aphidofagous coccinelids in the surroundings of crop fields during wintering periods and thus contribute to the sustainability of the beneficial fauna.
... A nivel mundial, los cambios en la forma de uso de la tierra han generado ambientes agrícolas muy simplificados en términos de biodiversidad ambiental, vegetal y animal (Ryszkowski & Jankowiak 2002). La disminución de la biodiversidad y la consecuente homogeneización del hábitat como resultado de las prácticas culturales más utilizadas por la agricultura moderna comprometen tanto la sustentabilidad como la estabilidad y la productividad futura de los ecosistemas agrícolas (Cohen 1999;Benton et al. 2003). En los agroecosistemas pampeanos se ha producido una disminución marcada de la diversidad de cultivos agrícolas, asociada al incremento de la dominancia del cultivo de soja. ...
ABSTRACT. Tussock grasses as shelters for overwintering arthropods in Pampean agroecosystems: effects
of plant size, clustering and architecture.
Perennial grasses are used as overwintering shelters by several arthropod species in the Pampa region. Plant size, structure, and clustering may condition habitat or shelter availability, and therefore their selection by overwintering arthropods. We analyzed the influence of clustering, size and architecture modification of Schizachyrium condensatum plants on the abundance and richness of these arthropods dwelling inside these plants. We set up plants of different sizes, from large (110 cm tall) to small (70 cm tall), along the edge of a field crop in the Rolling Pampas. They were planted isolated or in groups of five plants, with or without architecture modification (open or closed). After the winter season, overwintering arthropods were removed and the abundance and richness of morphospecies were calculated for each plant. Two predator species from the Coccinellidae family, Hippodamia convergens and Coccinella ancoralis, represented almost 90% of total abundance in large, grouped and closed plants. In large closed plants there was almost twice the abundance of arthropods than in large open plants. In small plants there was no effect due to architecture. In small plants there was similar arthropod richness between isolated and grouped plants, whereas in large plants there was almost twice the species in grouped than in isolated plants. Our results show that small plant size, as well as opening and isolation for large plants, negatively affected the choice of wintering sites for coccinelids. Therefore, we highlight the importance of conserving perennial grasses in the edges of agricultural areas as they allow the persistence of aphidofagous coccinelids in the surroundings of crop fields during wintering periods and thus contribute to the sustainability of the beneficial fauna.
... Los cambios en la forma de uso de la tierra han generado ambientes agrícolas muy simplificados en términos de biodiversidad ambiental, vegetal y animal (Ryszkowski & Jankowiak, 2002). La disminución de la biodiversidad y la consecuente homogeinización del hábitat como resultado de las prácticas culturales más utilizadas por la agricultura moderna, comprometen la sustentabilidad, la estabilidad y la productividad futura de los ecosistemas agrícolas (Cohen, 1999;Benton et al., 2003). ...
Abstract. Arthropod communities in vegetation of non-cultivated areas of southeastern Santa Fe.
A premise of the new models of agricultural production is the conformation of sustainable agricultural systems and a possible strategy to achieve it is to keep or restore the diversity of the rural landscape. This could be achieved by keeping the vegetation of the non-cultivated areas of the agroecosystems, such as the narrow edges between production fields or the stubbles of major surface. The aim of this work was to determine the specific composition and the trophic structure of epigean arthropods communities present in different types of crop edges and in neighboring crops; to establish the influence of different arrangements of vegetation, microclimate and soil factors on the structure of the arthropod fauna present in each environment, and to characterize the herbivory links and the flower-insect relations in the area under study. The thesis was carried out in Zavalla and Rosario, Santa Fe province, Argentina. The surface epigean arthropods were collected with pitfall traps, in each season, for two consecutive years. The herbivorous and floral visitors were evaluated by direct observation in transects, monitored one to three times per month. The sampling effort was of 8652 traps / days for surface epigean arthopods; 768 hours for herbivorous and 652 hours for floral visitors. A total of 516 species were identified, grouped in 24 orders and 99 families; 51.592 individuals of 209 species were captured with pitfall traps. In addition, 373 plant-insect relations were established; about 32 % of those are new records of herbivory, involving 205 herbivorous species. Furthermore, 375 flower-insect including relations 186 species of visitors were observed. In the edges some specific assemblages were established in which generalist predators, neutral herbivorous and several species of detritivorous predominate. No significative abundance of herbivorous plague was detected. These environments are not adequate refuge areas for the resistance management produced by genetically modified crop, due to the fact that the target species do not complete their cycle on the spontaneous flora. In these environments, the gliphosate tolerant native plants constitute an important resource for predators and polilectic pollinators. The herbivory net presents a strong tendency to the herbivorous specialism and to the generalism of the plants. On the contrary, the pollination system is of the generalist type with plants that are pollinated by several different species of animals and visitors that transport pollen of diverse species of plants. In conclusion, it is very convenient indeed to keep edges with spontaneous herbaceous vegetation and tree curtains in order to increase the heterogeneity of the otherwise agricultural homogeneous landscapes, and thus to promote biodiversity, with the consequent increase of the agroecosystems sustainability.
The concept of biodiversity as a key factor influencing the stability of insect populations within ecosystems is explored. Biodiversity, encompassing the diversity of plants, animals, and microorganisms in a given environment, serves as a crucial metric for evaluating ecological community resilience. Population ecologists emphasize the significance of biodiversity in assessing and comparing ecosystem stabilities, particularly in the context of Integrated Pest Management (IPM). Within agroecosystems, human activities such as monoculture farming and the widespread use of agricultural inputs like pesticides and fertilizers have led to modifications in natural ecosystem structures and reduced organism diversity. This alteration can impact the sustainability of ecosystems and influence the dynamics between cultivated plants, weeds, and associated organisms such as herbivores, carnivores, and decomposers. Studies have shown that a decline in ecosystem biodiversity often correlates with increased pest outbreaks and economic losses in agricultural settings. Therefore, biodiversity levels are considered indicative of ecosystem stability and potential pest outbreak risks. This chapter delves into the theoretical underpinnings of biodiversity assessments and the variety of indicators utilized to measure ecosystem diversity. Through the presentation of case studies and the demonstration of specialized software applications, readers are guided on how to effectively determine and monitor biodiversity levels within ecosystems, aiding in the prediction and prevention of pest outbreaks.
This review examines the potential for gene exchange in genetically modified organisms (GMOs) likely to be released into the environment. It considers both indirect and direct evidence for the exchange of genetic information in organisms and those circumstances where it may occur. The available scientific evidence indicates that horizontal transfer among divergent organisms in nature is not so infrequent that it can be dismissed, nor does it occur at a frequency comparable to related organisms. In considering the release of genetically modified microorganisms into the environment, DNA is more likely to be transferred between members of the same genus. There are numerous reports which show some conjugation, transduction and transformation systems may have broader host ranges than considered previously. There are established examples of interkingdom exchange between microorganisms and plants. The reverse process between some organisms indicates the potential for horizontal transfer may be greater than thought previously. Gene exchange may be a hazard but its consequences for the environment are likely to be dependent on the transferred gene and the expression of its trait in recipient organisms (plants or microorganisms) which acquire a selective advantage.
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