Agricultural Practices and Biodiversity Effects

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Questions and Answers

How does planned diversity in cropping systems contribute to total biodiversity?

Planned diversity in cropping systems enhances total biodiversity by influencing the composition and abundance of associated biota, including pest complexes and soil microorganisms.

What effects does agricultural intensification have on the pest complex in monocultural systems?

Agricultural intensification leads to reduced plant species diversity, resulting in a pest complex that is less diverse but more abundant, causing greater crop losses.

Why are lower insect pest densities observed in diverse crop systems like polyculture?

Lower insect pest densities in polyculture arise from altered host-finding behavior, increased predation, higher parasitism rates, and a greater ratio of natural enemies to herbivores.

How can genetic diversity within crop species help manage pathogen impacts on productivity?

Genetic diversity within crop species can mitigate pathogen impacts by mixing resistant and susceptible crops, where a higher proportion of resistant crops reduces pathogen spread. Signup and view all the answers

What potential has been noted regarding the use of crop diversity to manage insect and microbial pests?

The potential to use crop diversity for managing insect and microbial pests has not been extensively exploited, highlighting an area for further research and implementation. Signup and view all the answers

What are the primary factors contributing to the limited adoption of Integrated Pest Management (IPM) in agriculture?

Pesticides are cheaper and easier to apply, while IPM requires knowledge-intensive management. Signup and view all the answers

How does the diversity of soil biota in agricultural systems compare to that in natural ecosystems?

The diversity of soil biota in agricultural systems is typically less than half of that in natural ecosystems. Signup and view all the answers

What significant disturbances impact soil biota during the transition from natural forest to agricultural land?

Disturbances include the removal or burning of plant biomass and tillage, which can harm soil organisms like earthworms. Signup and view all the answers

In what specific way do climatic extremes influence soil biota activity?

Climatic extremes of temperature and moisture can either kill soil organisms or significantly reduce their activity levels. Signup and view all the answers

Despite the general reduction in soil biota diversity, what unique characteristic is observed in tropical pastures?

In tropical pastures, the abundance and biomass of soil fauna are usually enhanced. Signup and view all the answers

Study Notes

Agricultural Intensification and its Effects on Species Diversity

Farming practices, termed "planned diversity," dictate the composition of plant communities and influence the composition and abundance of associated organisms (e.g., pests, soil invertebrates, microorganisms).
Crop diversity is crucial for overall biodiversity and productive agricultural systems.

The Pest Complex

Herbivorous insects and microbial pathogens have significant impacts on plant productivity in agricultural and natural ecosystems.
Reduced plant diversity in intensive agriculture alters pest complex communities (insects, predators, parasites, microbes) impacting crop losses.
Monoculture systems often result in greater, but less diverse, pest populations.
Diverse crop systems (e.g., polyculture) tend to have lower pest densities due to factors like higher predation, parasitism, and natural enemies.
Genetic diversity within crop species influences resistance to crop pathogens and helps reduce pathogen spread.

Soil Biota

Soil communities play a critical role in nutrient cycling, soil structure, and other soil properties in natural ecosystems.
Agricultural intensification has been shown to significantly reduce soil biodiversity, sometimes to less than half of natural ecosystems.
Conversions from natural habitats to agricultural land dramatically disrupt soil communities, as does tillage, removal or burning of plant biomass.
Abrupt temperature and moisture changes impact soil biota, and reduced organic matter significantly alters competitive balance between organisms.

Interactions Between Agroeccosystems and Surrounding Regions

Agroecosystems interact with surrounding regions both biologically (e.g., nutrient cycling, pesticide use) and physically (e.g., wildlife movement).
Neighbouring ecosystems can influence agroecosystems, and vice versa, impacting factors like wildlife movement and habitat use.
Diverse agroecosystems can serve as important habitats for numerous animals, particularly birds. Their presence can influence pest control.
The cycling of nutrients is altered in agricultural systems through harvest and fertilizer applications, impacting organic matter and soil organisms.

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Description

Explore how agricultural intensification affects species diversity and pest dynamics. This quiz covers the importance of crop diversity in maintaining a productive ecosystem and examines the impacts of monoculture vs. polyculture practices on pest populations and plant productivity.