Chuva de sementes como indicador de restauração ecológica em matas ripárias do Distrito Federal

Abstract

Knowledge of the variation of seed rain contributes to the understanding of reproductive processes and dynamics of ecosystems can support programs to restore degraded areas . Projects to restore degraded environments require tools to assess the progress of the restoration. Ecological indicators that comprise these tools allows us to interpret the situation of the area to intervene . The objective of this study was to evaluate the seed rain as an indicator of ecological restoration in areas of riparian zones in the Federal District . 132 seed collectors were installed in two areas of riparian forests that differ in history of land use and landscape around ( Rio Jardim and Capão Comprido) . In each area plots to evaluate the contribution of seed rain in different ecological restoration techniques were demarcated. Each technique or combination of more than one was considered as treatment (nucleação de Anderson , linha de recobrimento e diversidade, poleiros, nucleação de Anderson + poleiro, and mata remanescentes). In each area different treatments were installed (according to the size of the area) , with three replicates (plots) . Diagonal of each plot of restoration treatments was distributed four collectors of seed rain (50 x 50 cm , 15 cm of soil , nylon mesh of 1 mm ²) . As each treatment had three repetitions, therefore 12 collectors / treatment / month. The material deposited in the traps was collected monthly for one year (March 2012 to February 2013 ) , in paper bags and screened at the Laboratory of Plant Biology (EMBRAPA Cerrados) and Laboratory of Conservation Biology (UNIMONTES). The seeds were separated with the aid of stereomicroscope and identified and quantified when possible in cash and dispersal mode . In Rio Jardim area was sampled in total 100.040 propagules (8337sem/m2) and 4053 (1351m2) and MR 96987 (10777sem/m2) in the APR. In Coité (Capão Comprido) was 74,316 propagules (3539sem/m2) and 5718 (1906sem/m2) and MR 68598 (3811sem/m2). With the largest quantities represented by invasive species Urochloa decumbens (Stapf)RD. In areas syndrome dispersion predominant in the area in the restoration process (APR) was anemocoric and remnant forest "non anemochory " was prevalent . Predominated seed sizes small (<2mm) in both areas . Variation occurred in the supply of seed rain between the months being the peak observed for the Jardim area in April and the Coité was in February . In both areas the differences between the supply of seed rain in APR (area being restored) and MR (remaining forest) were observed . In Jardim in the treatments with highest intakes of seed rain in abundance and richness were T3 (control ) and T4 (remaining forest) , respectively (p<0.001) . In Coité area were, respectively, T5 (diversity and coating line) and T7 (remaining forest) (p < 0.001). With the results obtained for both areas is possible to observe that the seed rain reflect the different situations in each area responding to small variations reflecting the conservation status of each environment and allowing to draw conclusions within the landscape . Because of this accuracy, sensitivity and measurability seed rain can be used as an indicator of ecological restoration in riparian areas , allowing the study to extract information about the regeneration capacity of the ecosystem . Can be used as an indicator of the potential for regeneration or as an indicator of self-maintenance to support interventions and best choice of methodologies for restoration .