Although plastic pollution happens globally, the micro- (<5 mm) and macroplastic (5–150 mm) transfer of plastic to terrestrial species relevant to human consumption has not been examined. We provide first-time evidence for micro- and macroplastic transfer from soil to chickens in traditional Mayan home gardens in Southeast Mexico where waste mismanagement is common. We assessed micro- and macroplastic in soil, earthworm casts, chicken feces, crops and gizzards (used for human consumption). Microplastic concentrations increased from soil (0.87 ± 1.9 particles g−1), to earthworm casts (14.8 ± 28.8 particles g−1), to chicken feces (129.8 ± 82.3 particles g−1). Chicken gizzards contained 10.2 ± 13.8 microplastic particles, while no microplastic was found in crops. An average of 45.82 ± 42.6 macroplastic particles were found per gizzard and 11 ± 15.3 macroplastic particles per crop, with 1–10 mm particles being significantly more abundant per gizzard (31.8 ± 27.27 particles) compared to the crop (1 ± 2.2 particles). The data show that micro- and macroplastic are capable of entering terrestrial food webs.
AbstractThe tropical montane cloud forest is one of the most biodiverse ecosystems on Earth and is one of the areas most threatened by anthropogenic disturbance. This study assessed the temporal impact on soil properties (organic carbon, total nitrogen, cation exchange capacity, bulk density) following establishment of native tree species in two degraded tropical montane cloud forest areas with different soil types and land-use intensities in south-east Mexico. In Pueblo Nuevo, Chiapas, Pinus chiapensis and Alnus spp. were established at two sites with humic Nitisols with low and moderate disturbance levels, respectively. In Xalapa, Veracruz, plum pine (Podocarpus matudae), American hornbeam (Carpinus caroliniana), Oaxaca walnut (Juglans pyriformis Liebm.), and sweetgum (Liquidambar styraciflua) were established on a grassland-covered humic Andosol with a high level of disturbance. After 16 years, soil properties had generally improved, although in the initial years after planting, the values declined, indicating a possible negative impact because of disturbance during tree establishment. Land-use intensity prior to tree establishment influenced the level of recovery in soil properties. The Pueblo Nuevo sites, with low to moderate disturbance levels, regained soil quality faster than the highly disturbed Xalapa site, despite better initial soil quality in the latter.
La región Puuc-Chenes está ubicada en el centro de la Península de Yucatán. Debido a que está rodeada por tres áreas naturales protegidas, constituye un importante eslabón para mantener la conectividad de la selva maya. Sin embargo, la expansión de la frontera agrícola en la región está favoreciendo la fragmentación del hábitat del jaguar (Panthera onca). En el presente estudio hemos analizado el grado de conectividad del paisaje para la región Puuc-Chenes con base en los requerimientos del hábitat de P. onca. Se usaron los programas ArcMap, FRAGSTATS e IDRISI para el análisis de la conectividad estructural y funcional del paisaje, el cual se basó en las diferencias conocidas de los requerimientos de hábitat para machos y para hembras. La selva fue la cobertura vegetal dominante al ocupar 49.8% del paisaje. El índice de contagio fue del 62.5% y el índice de contraste total de los bordes fue de 43.7%. De acuerdo con nuestros resultados, concluimos que la región Puuc-Chenes presenta una conectividad de paisaje estructural intermedia, ya que se identificó un corredor adecuado solo para machos y tres corredores para ambos sexos. Este estudio aporta elementos robustos basados en evidencias científicas que justifican la conservación de cuatro fragmentos de selva en la región Puuc-Chenes para preservar la conectividad del paisaje para Panthera onca en esta región.
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