Browsing by Subject "Ground beetles"

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  • Ariza, Gloria Maria; Jacome, Jorge; Kotze, D. Johan (2021)
    The tropical dry forest (TDF) ecosystem is characterised by strong seasonality exasperated periodically by the El Nino/southern oscillation (ENSO). The environment produced by this event could constrain the survival of small organisms, such as insects. Carabid beetles were collected in a TDF in Armero, Colombia, during wet and dry seasons in both El Nino and non-El Nino periods. A series of traits linked to desiccation resistance were measured to characterise their adaptation to the TDF environment and to investigate changes experienced by carabid beetles during both episodes in quantitative (assemblage) and qualitative (traits) parameters. We found no difference in the presence of traits between El Nino and non-El Nino episodes, but carabid assemblages changed significantly in composition and assemblage structure between these episodes. During both periods, small-sized and nocturnal species dominated the assemblages, but in terms of number of individuals, medium and large-sized, and visual hunter species dominated. Calosoma alternans and Megacephala affinis were the most abundant species with high dispersal capacity. Carabid beetles exhibited morphological traits well-adapted to drought experienced in TDF, including when it is exasperated by ENSO. However, long-term studies can help to elucidate the real effects of ENSO and to confirm the adaptation of carabid beetles to cope with this extreme environment.
  • Rainio, J.; Niemelä, J. (Kluwer Academic Publishers, 2003)
    One of the primary goals of research on bioindicators is to identify species or other taxonomic units that would reliably indicate disturbances in the environment, and reflect the responses of other species or the overall biodiversity. However, there is no perfect bioindicator and selecting the most suitable one depends to a great extent on the goal of the survey. In this paper we examine the suitability of carabids as bioindicators. Carabids are frequently used to indicate habitat alteration. They have been used in grasslands and boreal forests where species number and/ or abundances have been noted to change along a habitat disturbance gradient. A common trend is that large, poorly dispersing specialist species decrease with increased disturbance while small generalist species with good dispersal ability increase. Some species are not affected by moderate disturbance. There is, however, not enough research to determine how suitable carabids are for biodiversity studies, or how well they represent the response of other species. We conclude that carabids are useful bioindicators, but as crucial understanding of their relationship with other species is incomplete, they should be used with caution.