Local land‐use intensity and surrounding landscape complexity affect the diversity of local species. Ants are an important biocontrol agent of the coffee berry borer (CBB), the main coffee pest worldwide. Although intensification of coffee production and deforestation in the surrounding landscape may reduce ant diversity, α‐ and β‐diversity patterns of ants in coffee landscapes remain poorly understood. Ants foraging in coffee bushes were sampled, using tuna baits along an agricultural intensification gradient (forest, shaded coffee and sun coffee) in a Neotropical coffee landscape. We evaluated the differences in α and β components of ant richness, community differentiation and habitat specificity of ant communities, in response to land‐use type and the percentage of surrounding forest. We found that ant β‐diversity and community differentiation among plots were significantly reduced with coffee management intensity. The amount of forest border adjacent to coffee plantations did not affect α‐ or β‐diversity. Yet, ant habitat specificity in the forest increased with plots having greater amounts of forest border, although in sun coffee plantations, the opposite was found: plots with greater forest border decreased habitat specificity. We found that conserving forest at landscape scales enhanced β‐diversity, community differentiation and habitat specificity of ants in the forest. Loss of forest cover at landscape scales (i.e. predominance of sun coffee) may lead to biotic homogenisation of ant communities. In conclusion, landscape‐wide ant richness is important in terms of biological CBB control by conservation.

ResumenEn los países en desarrollo, los biorresiduos son la fracción predominante de los residuos sólidos municipales (RSM); los biorresiduos tienen un alto contenido de materia orgánica, característica que favorece su transformación a través de procesos biológicos como la digestión anaerobia (DA). En este estudio, mediante ensayos de potencial bioquímico de metano (PBM), se evaluó la influencia de la relación sustrato-inóculo (S/I) sobre la DA de biorresiduos de origen municipal (BOM), utilizando relaciones de 0.25 a 9 gSVsustrato*gSVinóculo-1. Como inóculo se empleó lodo de un biodigestor anaerobio de una planta de tratamiento de aguas residuales domésticas. Se encontró que la relación S/I tiene efecto sobre la DA de los BOM (p < 0.1), en donde la relación 0.25 produjo los mejores resultados (producción de 176.19 mLCH4*gSV-1 y un índice de biodegradabilidad de 73.12%, mientras que la relación de 9 generó los más bajos resultados (17.56 mLCH4*gSV-1 y 7.29%, respectivamente). También se encontró que las relaciones S/I menores de 2 gSVsustrato*gSVinóculo-1 permiten un proceso adecuado; con valores mayores, el proceso se desestabiliza debido a la ocurrencia de procesos de acidificación por la acumulación de los AGV's que no logran estabilizarse por la baja capacidad buffer del sistema.AbstractBiowastes are the predominant fraction of municipal solid waste (MSW) of developing countries. Biowastes are characterized by a high content of organic matter; characteristics which facilitates its transformation through biological processes such as anaerobic digestion (AD). Using biochemical methane potential (PBM) assays, in this study we evaluated the influence of substrate-inoculum (S/I) ratio on the AD of biowaste from MSW. The S/I ranged between 0.25 to 9 gSVsubstrate * gSVinoculum-1. Sludge from an anaerobic digester of the domestic wastewater treatment plant located in Cali-Colombia, was used as inoculum. It were found that the S/I ratio has an effect on the AD (p < 0.1). Best results was obtained with the ratio 0.25 gSVsubstrate*gSVinoculum-1 (176.19 mLCH4*gSV-1 and a rate of 73.12% biodegradability), while 9 gSVsubstrate*gSVinoculum-1 produced the lowest results (17.56 and 7.29% respectively). Furthermore, it was found that S/I ratios lower than 2 gSVsubstrate*gSVinoculum-1 provided a suitable process. In the other hand, with S/I ratios greater than 2, the process becomes unstable due to acidification processes, caused by accumulation of VFA's; those VFA's cannot be he stabilized due to the low buffering capacity of the system

Municipal bio-wastes-MBW are characterized by their high content of organic matter, humidity, nutrients, and additionally are wastes easily acids, which makes them a source of pollution when are improperly disposed. Anaerobic digestion-AD is a technological alternative for MBW pollution control as well as for methane production as a renewable energy source; however, parameters such as pH can affect the process. This study evaluated at laboratory scale thought Biochemical Potential Methane-BPM assays at a temperature of 30oC during 40 days, the influence of pH on the MBW-AD. The pH values tested ranged from 5.5 to 8.0 units, using as inoculum sludge coming from the sludge anaerobic digestion of a domestic wastewater treatment plant. It was noticed that the acid pH between 5.5 and 6.0 units had the lowest methane production, 70.0 and 71.0mLCH4*gVS-1 respectively; while pH values near to the neutrality achieved the best results, being the highest production of methane corresponding to a pH of 7.0 units, reaching a value of 126.0mLCH4*gVS-1. Similarly, it was found that pH values from 7.0 to 8.0 units had the best buffer capacity, ensuring stability of the anaerobic process and avoiding inhibition phenomena. To achieve this condition, it is necessary to apply pH adjust due to the acid characteristics of the MBW. Los biorresiduos de origen municipal-BOM, se caracterizan por su alto contenido de materia orgánica, humedad y nutrientes, además de ser residuos fácilmente acidificables, lo que los convierte en una fuente contaminante cuando se disponen inadecuadamente. La digestión anaerobia-DA es una alternativa tecnológica para el control de la contaminación de los BOM y la obtención de una fuente de energía renovable, como el metano; sin embargo, variables, como el pH, pueden afectar el proceso. Este estudio evaluó, a escala de laboratorio, mediante ensayos de Potencial Bioquímico de Metano-PBM, a una temperatura de 30oC, durante 40 días, la influencia del pH sobre la DA de BOM. Los valores de pH del sustrato variaron entre 5,5 a 8,0 unidades, utilizando como inóculo lodo, proveniente de la biodigestión anaerobia de lodos, de una planta de tratamiento de aguas residuales domésticas. Se evidenció que los pH ácidos correspondientes a 5,5 y 6,0 unidades, presentaron la menor producción de metano, del orden de 70,0 y 71,0 mLCH4*gSV-1, respectivamente, mientras que los pH cercanos a la neutralidad, lograron los mejores resultados, siendo la producción a un pH de 7,0 unidades la mayor, la cual, fue 126,0mLCH4*gSV-1. Los resultados están acordes con el comportamiento de la capacidad buffer, que fue más adecuada, entre 7,0 y 8,0 unidades, garantizando estabilidad del proceso anaerobio y evitando así la ocurrencia de fenómenos de inhibición. Para lograr estos niveles de pH, se hace necesario adicionar un alcalinizante, debido a las características ácidas de los BOM.