| Summary: | In the past 10 years we have witnessed the beginnings of the study of soil
ecology as a unified science, and the general realization by soil scientists, farmers,
and land managers that many of the most important economic aspects of soil health
are controlled by biological factors.
This research focuses on alterations in a tropical soil microarthropod
community under differing intensive agricultural protocols: native vegetation,
pastures and cropland, during June, July and August 1998. The effect of pesticides
in potato cultivation was also studied.
In the Ecuadorean montane forest, 361 morphospecies of soil arthropods,
were classified during the three sampling months. August was the month with
highest abundance and diversity. Acari, Coleoptera, Collembola, Diptera and
Homoptera were the most abundant orders present in all the three types of land
management.
The native vegetation had the most abundant and diverse representation of
all soil arthropod taxa compared to the pastures and croplands. Coleoptera, Diptera,
Diplopoda, Diplura and Hemiptera were significantly more diverse in native
vegetation than in pastures and croplands. The most abundant functional groups
were the fungivores, herbivores and predators. The abundance of functional groups
was significantly higher in the native vegetation for predators, herbivores and
detritivores.
115 morphospecies of soil arthropods were identified in the study of arthropod
response to pesticides in a complete randomized potato plot. Seasonal effects were
documented for Acari, Collembola, Diptera, and Homoptera. Predators were most
abundant in July and fungivores decreased in September. Neither arthropod orders nor
functional groups showed a significant change in abundance between different
treatments. Only Homoptera showed an increase in its abundance in the third
sampling date and only in the Antracol plots. The potato plants in the whole block
showed poor productivity, suggesting that the whole system was stressed by the fungal
pest. === Graduation date: 2000
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