¿Pueden los incendios afectar a las comunidades de hormigas epígeas e hipógeas (Hymenoptera: Formicidae) de Cerrado de la misma manera?

Fire occurrences are a common perturbation in Cerrado ecosystems, and may differently impact the local biodiversity. Arthropods are one of the taxa affected by fires, and among them, ants are known as good bioindicators. We aimed to evaluate the effect of anthropic fires on epigaeic and hypogaeic ant communities (species richness and composition) in Cerrado areas with different post-fire event recovery periods. We conducted the study in four Cerrado areas during two weeks of 2012 dry season: one unburned and three at different post-fire times (one month, one and two years). We sampled ants with pitfall traps in epigaeic and hypogaeic microhabitats. We collected 71 ant morpho-species from 25 genera. In the epigaeic microhabitat we sampled 56 morpho-species and 42 in the hypogaeic microhabitat. The area with the shortest recovery time presented lower epigaeic ant species richness (4.3 ± 2.00) in comparison to the other areas (8.1 ± 2.68 species on one year area; 10.3 ± 2.66 species on two years area; 10.4 ± 2.31 species on control area), but recovery time did not affect hypogaeic ant species richness. Regarding ant species composition, fire did not directly affect hypogaeic ant species, which remained the same even one month after fire event. However, two years were not enough to reestablish ant species composition in both microhabitats in relation to our control group samples. Our study is the first to assess anthropic fire effects upon epigaeic and hypogaeic ants communities; highlighting the importance of evaluating different microhabitats, to more accurately detect the effects of anthropic disturbances in biological communities. We concluded that ant communities are just partially affected by fire occurrences, and epigaeic assemblages are the most affected ones in comparison to hypogaeic ants. Furthermore the study provides knowledge to aid in the creation of vegetation management programs that allow Cerrado conservation.Los incendios son una alteración común en los ecosistemas del Cerrado brasileño y pueden causar diferentes efectos sobre la biodiversidad. Los artrópodos son uno de los taxones comúnmente afectados por el fuego, y entre ellos, se conoce que las hormigas son buenos bioindicadores. El objetivo de este trabajo fue evaluar el efecto de los incendios antrópicos sobre las comunidades de hormigas epígeas e hipógeas (riqueza de especies y composición) en áreas del Cerrado en diferentes tiempos de recuperación. Para ello, el estudio se realizó en cuatro áreas del Cerrado durante la temporada seca del 2012: una área no quemada y otras tres áreas en diferentes momentos post-incendio (un mes, uno y dos años). Las hormigas fueron muestreadas utilizando trampas de caída en los microhábitats epígeo e hipógeo. Fueron recolectadas 71 morfo-especies de hormigas pertenecientes a 25 géneros. En el microhábitat epígeo recolectamos 56 morfo-especies y en el microhábitat hipógeo 42. El área con el menor tiempo de recuperación presentó una menor riqueza de especies de hormigas epígeas (4.3 ± 2.00) en comparación con las otras áreas (8.1 ± 2.68 especies en el área de un año; 10.3 ± 2.66 especies en el área de dos años; 10.4 ± 2.31 especies en el área de control), pero el tiempo de recuperación no afectó riqueza de especies de hormigas hipógeas. En cuanto a la composición de especies, el fuego no afectó directamente a las especies de hormigas hipógeas, la cual se mantuvo igual, incluso un mes después del incendio. Sin embargo, dos años no fueron suficientes para restablecer la composición de especies de hormigas en ambos microhábitats en relación con las muestras del área control. Nuestro estudio es el primero en evaluar los efectos del fuego antrópico sobre las comunidades de hormigas epígeas y hipógeas; se destaca la importancia de la evaluación de diferentes microhábitats para detectar con mayor precisión los efectos de las alteraciones antrópicas en las comunidades biológicas. Las comunidades de hormigas son solo parcialmente afectadas por incendios y las epígeas son las más perjudicadas. Además, este estudio proporciona conocimientos que pueden ayudar a la creación de programas de manejo de la vegetación del Cerrado, lo que permite conservar este importante bioma brasileño

Isolated and Community Contexts Produce Distinct Responses by Host Plants to the Presence of Ant-Aphid Interaction: Plant Productivity and Seed Viability

<div><p>Ant-aphid interactions may affect host plants in several ways, however, most studies measure only the amount of fruit and seed produced, and do not test seed viability. Therefore, the aim of this study was to assess the effects of the presence of ant-aphid interactions upon host plant productivity and seed viability in two different contexts: isolated and within an arthropod community. For this purpose we tested the hypothesis that in both isolated and community contexts, the presence of an ant-aphid interaction will have a positive effect on fruit and seed production, seed biomass and rate of seed germination, and a negative effect on abnormal seedling rates, in comparison to plants without ants. We performed a field mesocosm experiment containing five treatments: Ant-aphid, Aphid, Community, Ant-free community and Control. We counted fruits and seeds produced by each treatment, and conducted experiments for seed biomass and germinability. We found that in the community context the presence of an ant-aphid interaction negatively affected fruit and seed production. We think this may be because aphid attendance by tending-ants promotes aphid damage to the host plant, but without an affect on seed weight and viability. On the other hand, when isolated, the presence of an ant-aphid interaction positively affected fruit and seed production. These positive effects are related to the cleaning services offered to aphids by tending-ants, which prevent the development of saprophytic fungi on the surface of leaves, which would cause a decrease in photosynthetic rates. Our study is important because we evaluated some parameters of plant fitness that have not been addressed very well by other studies involving the effects of ant-aphid interactions mainly on plants with short life cycles. Lastly, our context dependent approach sheds new light on how ecological interactions can vary among different methods of crop management.</p></div

Traits and viability of seeds produced.

<p>Seed biomass (A) and number of abnormal seedlings (B) for the treatments: Control—caged plants without ant-aphid interaction, and exclusion of all the arthropods from the plant; Community–cageless plants with free access to the entire arthropod community; and Ant free community–plants with ant exclusion. The isolated treatments Aphid and Ant-aphid did not produce seed amount enough to seed traits experiments.</p

Plants production (fruits and seeds) per treatment.

<p>Produced fruits (A) and seeds (B) for the treatments: Control—caged plants without ant-aphid interaction, and exclusion of all the arthropods from the plant; Aphid–caged plants infested by aphids, and exclusion of others arthropods, including ants; Ant-aphid–caged plants with the presence of the ant-aphid interaction only, and exclusion of other arthropods; Communit<b>y</b>–cageless plants with free access to the entire arthropod community; and Ant free community–plants with ant exclusion.</p

ATLANTIC ANTS: a data set of ants in Atlantic Forests of South America

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