ABSTRACT
The intensive shift on land cover by anthropogenic activities have led to changes in natural habitats and environmental contamination, which can ultimately impact and threat biodiversity and ecosystem services, such as pollination. The aim of this study was to evaluate the effect of native forest and human-modified land covers on the concentrations of chemical elements accumulated in the neotropical pollinator bee T. angustula. Eight landscapes, within an Ecological Corridor in the State of São Paulo, Brazil, with gradients of forest cover, spatial heterogeneity and varying land covers were used as sampling unities. Bees collected in traps or through actives searches had the concentration of 21 chemical elements determined by ICP-MS. Results show a beneficial effect of forested areas on the concentrations of some well-known toxic elements accumulated in bees, such as Hg, Cd, and Cr. Multivariate Redundancy Analysis (RDA) suggests road as the most important driver for the levels of Cr, Hg, Sb, Al, U, As, Pb and Pt and bare soil, pasture and urban areas as the landscape covers responsible for the concentrations of Zn, Cd, Mn, Mg, Ba and Sr in bees. The results reinforce the potential use of T. angustula bees as bioindicators of environmental quality and also show that these organisms are being directly affected by human land use, offering potential risks for the Neotropical ecosystem. Our study sheds light on how land covers (native forest and human-modified) can influence the levels of contaminants in insects within human-dominated landscapes. The generation of predictions of the levels of toxic metals and metalloids based on land use can both contribute to friendly farming planning as well as to support public policy development on the surrounding of protected areas and biodiversity conservation hotspots.
Subject(s)
Bees/physiology , Environmental Monitoring , Metalloids/metabolism , Metals/metabolism , Agriculture , Animals , Biodiversity , Brazil , Ecosystem , Forests , Heavy Metal Poisoning , Humans , Pollination , SoilABSTRACT
Abstract: Rapid land-use/land cover changes (LULCC) have led to habitat loss and fragmentation in the natural forest areas, which are mainly due to the intense and rapid expansion of urban areas and intense agricultural management. These processes are strongly threatening biodiversity maintenance and the ecosystem services provided by them. Among the ecosystem services under threat, pollination has been widely studied since this service is essential to promote food production and, therefore, human well-being. In a scenario of increasing LULCC it is crucial to understand the interplay between these changes, pollination demand by insect-dependent crops and pollinator availability to ensure these ecosystem services meet the increased demand for food production. In this study, we developed a conceptual model to disentangle the relationships between human-nature, especially LULCC, and its consequences, to the delivery of pollination service. We also presented a case study in the Brazilian São Paulo state, where we modeled the effects of predicted LULCC associated to agriculture expansion between the years 2012 and 2030 on pollinator demand by crops and pollinator supply, for fourteen economically important crops. Additionally, we systematized an expert-based Ecosystem Service matrix to estimate the influences of LULCC on the provision of pollination. Our results showed that by 2030, the demand for pollination will increase by 40% on average, while pollinator supply, estimated using suitability values for the different land-use/cover classes, will show, on average, a 3% decrease. Our results highlight the importance of considering the dialogue among stakeholders, governments, institutions, and scientists to find alternatives and strategies to promote pollinator-friendly practices and safeguard the provision of pollination services in a future under LULCC.
Resumo: As aceleradas mudanças de uso e cobertura do solo levaram à perda e fragmentação de habitat das florestas naturais, principalmente devido a uma intensa e rápida expansão de áreas urbanas e ao intensivo manejo agrícola. Esses processos ameaçam fortemente a manutenção da biodiversidade e os serviços ecossistêmicos associados. Entre os serviços ecossistêmicos ameaçados, a polinização tem sido amplamente estudada, pois se trata de um serviço essencial para a produção de alimentos e, consequentemente, para o bem-estar humano. Em um cenário de crescentes mudanças no uso e cobertura do solo, é crucial entender a interação entre essas mudanças, a demanda de polinização por culturas dependentes de insetos e a disponibilidade de polinizadores para garantir que esse serviço ecossistêmico atenda o aumento da demanda produtiva de alimentos. Neste estudo, desenvolvemos um modelo conceitual para evidenciar as relações homem-natureza, especialmente as consequências das mudanças de uso e cobertura do solo sobre a prestação do serviço de polinização. Nós também apresentamos um estudo de caso no estado brasileiro de São Paulo, onde modelamos os efeitos de mudanças de uso e cobertura do solo associados à expansão de agricultura entre os anos de 2012 e 2030 e as demandas e oferta de polinizadores por cultura, para quatorze culturas economicamente importantes. Além disso, sistematizamos uma matriz de serviços ecossistêmicos baseada em conhecimento de especialistas para estimar as influências das mudanças de uso e cobertura do solo na provisão do serviço de polinização. Nossos resultados mostraram que até 2030, a demanda por polinização aumentará em média 40%, enquanto a oferta de polinizadores estimada, usando valores de adequação para as diferentes classes de uso e cobertura do solo, terá uma redução média de 3%. Nossos resultados destacam a importância do diálogo entre agricultores e outros importantes agentes impulsionando as mudanças de uso do solo, governos, instituições e cientistas para encontrar alternativas e estratégias para promover práticas favoráveis aos polinizadores e salvaguardar a prestação de serviços de polinização em cenários futuros de mudanças de uso e cobertura do solo.
