RESUMO

Background: Anthropogenic activities significantly impact natural ecosystems, leading to alterations in plant and pollinator diversity and abundance. These changes often result in shifts within interacting communities, potentially reshaping the structure of plant-pollinator interaction networks. Given the escalating human footprint on habitats, evaluating the response of these networks to anthropization is critical for devising effective conservation and management strategies. Methods: We conducted a comprehensive review of the plant-pollinator network literature to assess the impact of anthropization on network structure. We assessed network metrics such as nestedness measure based on overlap and decreasing fills (NODF), network specialization (H2'), connectance (C), and modularity (Q) to understand structural changes. Employing a meta-analytical approach, we examined how anthropization activities, such as deforestation, urbanization, habitat fragmentation, agriculture, intentional fires and livestock farming, affect both plant and pollinator richness. Results: We generated a dataset for various metrics of network structure and 36 effect sizes for the meta-analysis, from 38 articles published between 2010 and 2023. Studies assessing the impact of agriculture and fragmentation were well-represented, comprising 68.4% of all studies, with networks involving interacting insects being the most studied taxa. Agriculture and fragmentation reduce nestedness and increase specialization in plant-pollinator networks, while modularity and connectance are mostly not affected. Although our meta-analysis suggests that anthropization decreases richness for both plants and pollinators, there was substantial heterogeneity in this regard among the evaluated studies. The meta-regression analyses helped us determine that the habitat fragment size where the studies were conducted was the primary variable contributing to such heterogeneity. Conclusions: The analysis of human impacts on plant-pollinator networks showed varied effects worldwide. Responses differed among network metrics, signaling nuanced impacts on structure. Activities like agriculture and fragmentation significantly changed ecosystems, reducing species richness in both pollinators and plants, highlighting network vulnerability. Regional differences stressed the need for tailored conservation. Despite insights, more research is crucial for a complete understanding of these ecological relationships.

Assuntos

RESUMO

BACKGROUND AND AIMS: The majority of the earth's land area is currently occupied by humans. Measuring how terrestrial plants reproduce in these pervasive environments is essential for understanding their long-term viability and their ability to adapt to changing environments. METHODS: We conducted hierarchical and phylogenetically-independent meta-analyses to assess the overall effects of anthropogenic land-use changes on pollination, and male and female fitness in terrestrial plants. KEY RESULTS: We found negative global effects of land use change (i.e., mainly habitat loss and fragmentation) on pollination and on female and male fitness of terrestrial flowering plants. Negative effects were stronger in plants with self-incompatibility (SI) systems and pollinated by invertebrates, regardless of life form and sexual expression. Pollination and female fitness of pollination generalist and specialist plants were similarly negatively affected by land-use change, whereas male fitness of specialist plants showed no effects. CONCLUSIONS: Our findings indicate that angiosperm populations remaining in fragmented habitats negatively affect pollination, and female and male fitness, which will likely decrease the recruitment, survival, and long-term viability of plant populations remaining in fragmented landscapes. We underline the main current gaps of knowledge for future research agendas and call out not only for a decrease in the current rates of land-use changes across the world but also to embark on active restoration efforts to increase the area and connectivity of remaining natural habitats.

RESUMO

Brazil is among the main contributors to global biodiversity, which, in turn, provides extensive ecosystem services. Agriculture is an activity that benefits greatly from these ecosystem services, but at the same time is degrading aquatic and terrestrial ecosystems and eroding Brazilian biodiversity. This conflict is growing, as emerging unsustainable legislative proposals that will benefit the agricultural sector are likely to accelerate the decline of biodiversity. One such initiative (Bill 1282/2019) would change Brazil's "Forest Code" (Law 12,651/2012) to facilitate construction of irrigation dams in Permanent Preservation Areas, a category that includes strips (with or without vegetation) along the edges of watercourses. Two other similar bills are advancing through committees in the Chamber of Deputies. Here we provide details of these three bills and discuss their consequences for Brazil's biodiversity if they are approved. Expected negative impacts with changes in the legislation include: increased deforestation; siltation; habitat fragmentation; introduction of non-native species; reduction in the availability of aquatic habitats; and changes in biogeochemical process. These proposals jeopardize biodiversity and may compromise the negotiations for an agreement between Mercosur and the European Union.

Assuntos

RESUMO

In this study, we conducted a retrospective survey of 63 giant anteaters (Myrmecophaga tridactyla) using the Federal University of Uberlândia, Minas Gerais State, Brazil as reference site for wild animals. We analyzed the clinical records of 63 animals from January 2016 to February 2020. The information obtained included the location where the anteater was found, the reason for rescue, estimated life stage, gender, weight, general condition of the animal, clinical signs, diagnosis, and destination. Of the 63 animals, 30.15%, (n = 19/63) were found in rural areas, 25.40% (n = 16/63) in urban areas, and 22.22% (n = 14/63) near highways. The main reason for rescue was run-over accidents (n = 18/63, 28.60%). Regarding life stage distribution, 27% (n = 17/63) were cubs, 25.40% (n = 16/63) were adolescent, and 41.26% (n = 26/63) were adults. There was a higher frequency of females (n = 35/63, 56%), and three (9%) of them were pregnant or had cubs. For injury evaluation, three of the 63 giant anteaters were dead on arrival at the rehabilitation site; therefore, we excluded them from this aspect of the study. Of the 60 remaining anteaters, only 13.33% (n = 8/60) of the animals were healthy upon physical examination.The most common condition was traumatic brain injury (n = 32/60 53.33%), followed by fractures (n = 23/60, 38.33%), neonate triad (n = 15/60, 25%), and abrasions (n = 15/60, 25%). The animals presented a high mortality rate (n = 39/60, 65%). The low number of giant anteaters reintroduced to their natural habitat and the high mortality rate of animals sent to rehabilitation centers show that the protection of giant anteaters is important to reduce the number of these animals sent to rehabilitation centers.

Foi realizado um levantamento retrospectivo de 63 tamanduás-bandeira (Myrmecophaga tridactyla) atendidos em um centro de animais selvagens referência na Universidade Federal de Uberlândia, Minas Gerais, Brasil. Foram analisados registros clínicos de 63 animais de janeiro de 2016 a fevereiro de 2020. As informações coletadas foram: local onde foi encontrado, motivo do resgate, idade estimada, sexo, peso, estado geral do animal, sinais clínicos, diagnóstico e destinação. Os animais foram encontrados em áreas rurais (30.15%, n = 19/63), áreas urbanas (25.40%, n = 16/63) e próximo a rodovias (22.22%, n = 14/63). O principal motivo do resgate foram os atropelamentos (28.60%, n = 18/63). A faixa etária foi de 27% (n = 17/63) filhotes, 25.40% (n = 16/63) jovens e 41.26% (n = 26/63) adultos. Encontrou-se maior frequência de fêmeas (56%, n = 35/63), sendo que três (9%) estavam prenhes ou com os filhotes nas costas. Apenas 13.33% (n = 8/60) dos animais apresentavam-se saudáveis ao exame físico. A condição mais comum foi traumatismo cranioencefálico (53,33%, n = 32/60), seguida por fraturas (38.33%, n = 23/60), tríade neonatal (25%, n = 15/60) e escoriações (25%, n = 15/60). Os animais apresentaram alta taxa de mortalidade (65%, n = 39/60). O baixo número de tamanduás reintroduzidos em seu habitat natural e a alta taxa de mortalidade de animais encaminhados para centros de reabilitação, mostram a importância de medidas que os protejam a ponto de reduzir o número de animais encaminhados para esses centros.

RESUMO

Habitat fragmentation is considered an important threat to biodiversity, increasing species exposure to edge effects. The Brazilian Cerrado savanna is considered a biodiversity hotspot and has been converted to small, isolated fragments due to human activities. Ant communities and colony survivorship are known to be affected by edge effects in Cerrado, but to date there is no information on the genetic diversity of ant colonies at the edge of fragmented areas. Here, we investigate if colony genetic diversity and structure of Odontomachus chelifer (Latreille) ants (Hymenoptera: Formicidae) are subject to edge effects in a Cerrado reserve in southeast Brazil. Using microsatellites, we evaluated the number of breeders (queens and males) and the genetic diversity in O. chelifer colonies located in the interior versus edge of a Cerrado fragment. All O. chelifer nests had multiple queens, which presented a low mating frequency. The number of breeders and most estimates of genetic diversity did not differ between colonies at the edge versus interior of the fragment. Genetic structure was not influenced by nest location as well. However, we detected a small and positive increase in the observed heterozygosity in colonies located at fragment edges. High heterozygosity is thought to be particularly important in fast-changing environments, such as edges, providing an advantage for genetic diversity. Further investigation is needed to assess in greater detail how habitat loss affects O. chelifer biology. Our study is a first step toward elucidating edge effects on genetic diversity of ant colonies, a topic still poorly explored in tropical environments.

Assuntos

RESUMO

Industrial, agricultural, and urban areas can be sources of pollution and a cause of habitat fragmentation. The Conlara River located in the northeast of San Luis Province suffers different environmental pressures along its course from urban to agro-industrial areas. The present study aims to assess the water quality of the Conlara basin by evaluating how metals and pesticide contamination as well as physicochemical parameters relate to physiological stress in Jenynsia multidentata. Samplings were carried out in four sites characterized by a growing gradient of anthropic impact from the springs to the final sections of the river, starting with tourism passing through urban areas and ending with large agricultural areas (from S1 to S4) during both the dry and wet seasons. A total of 27 parameters were determined (11 physicochemical, 9 heavy metals, and 7 pesticides) in surface waters. Biomarkers (CAT, TBARS, ChE, and MN) showed significant physiological and cytological alterations in J. multidentata depending on the hydrology season. The combination of physicochemical parameters, metals, and pesticide levels allowed typification and differentiation of the sites. Some metal (Cr, Mn, Pb, and Zn) and pesticide (α-BHC, chlorpyrifos, permethrin and cypermethrin, and endosulfan α) levels recorded exceeded the recommended Argentinian legislation values. A principal component analysis (PCA) allowed detection of differences between both seasons and across sites. Furthermore, the differences in distances showed by PCA between the sites were due to differences in the presence of physicochemical parameters, metals, and pesticides correlated with several biomarkers' responses depending on type of environmental stressor. Water quality evaluation along the Conlara River shows deterioration and different types of environmental stressors, identifying zones, and specific sources of pollution. Furthermore, the biomarkers suggest that the native species could be sensitive to anthropogenic environmental pressures.

RESUMO

Abstract Knowledge of taxonomy and biodiversity of parasites is fundamental to better understand ecosystem dynamics. The objective of this study was to describe the helminth fauna of two species of marsupials in five fragments of the Atlantic rainforest in the western region of Paraná State, Brazil. In a total of 4050 trap-nights, the animals were captured using Sherman, Tomahawk, and Pitfall traps, euthanized, necropsied, and their organs inspected for helminths. After identification of the parasites, descriptors of infection, such as prevalence, mean abundance, mean intensity, and range of intensity, were calculated. Collectively, six helminth species were observed in 18 animals. The following five species were observed in Marmosa paraguayana: Viannaia hamata (58.8%), Gracilioxyuris agilisis (52.9%), Travassostrongylus sextus (17.6%), Oncicola luehei (5.9%), and Pritchardia boliviensis (5.9%). Whereas the following two species were observed in Monodelphis dimidiata: Trichohelix tuberculata (100%) and Travassostrongylus sextus (100%). This study represents a new locality record for all helminths described herein, and a new host for four helminth species. This is the first report on the helminth fauna of Monodelphis dimidiata, expanding knowledge about marsupials in the Brazilian Atlantic Forest.

Resumo Conhecimentos taxonômicos e da biodiversidade parasitária são fundamentais para uma melhor compreensão da dinâmica do ecossistema. O objetivo do estudo foi descrever a helmintofauna de marsupiais em cinco fragmentos de Mata Atlântica, na região Oeste do Estado do Paraná, Brasil. Em um total de 4.050 armadilhas/noite, os animais foram capturados com as do tipo Sherman, Tomahawk e Pitfall, eutanasiados, necropsiados e seus órgãos inspecionados em busca de helmintos. Após a identificação do parasita, foram calculados os indicadores de infecção (prevalência, abundância média, intensidade média e variação de intensidade). Seis espécies de helmintos foram observadas em dezoito animais; cinco em Marmosa paraguayana: Viannaia hamata (58,8%), Gracilioxyuris agilisis (52,9%), Travassostrongylus sextus (17,6%), Oncicola luehei (5,9%) e Pritchardia boliviensis (5,9%), e duas em Monodelphis dimidiata: Trichohelix tuberculata (100%) e Travassostrongylus sextus (100%). Este estudo representa um novo registro de localidade para todos os helmintos descritos e um novo hospedeiro para quatro deles. Trata-se do primeiro relato da helmintofauna de Monodelphis dimidiata, expandindo-se os conhecimentos sobre marsupiais na mata Atlântica brasileira.

RESUMO

Mangaba tree is a fruit tree species whose natural populations are fragmented by anthropic actions. For this reason, studies assessing the impact of fragmentation on the diversity and genetic structure of these populations are required in order to establish suitable conservation strategies. In our study, we used data from analyzes through microsatellite markers in computer simulations to estimate the rates of migration and selfing of six mangaba populations. The studied populations are located in the northeastern states of Ceará, Pernambuco and Sergipe. We tested different selfing and migration rates and selected the combination that showed values of observed and expected heterozygosity closest to those previously obtained with microsatellite markers. According to our simulations, selfing and migration were moderate. This may have led to an increase in inbreeding and genetic drift, resulting in low genetic diversity. We recommend expanding the area and reducing disturbance to promote the occurrence of pollinators, which play an important role in increasing genetic diversity.

A mangabeira é uma espécie frutífera cujas populações naturais se encontram fragmentadas por ações antrópicas. Desse modo, são necessários estudos sobre a avaliação do impacto da fragmentação sobre a diversidade e estrutura genética dessas populações para o estabelecimento de estratégias de conservação adequadas. No presente estudo, foram utilizados dados de análises com marcadores microssatélites em simulações computacionais para estimar as taxas de migração e autofecundação de seis populações de mangaba. As populações estudadas estão localizadas nos estados nordestinos do Ceará, Pernambuco e Sergipe. Foram testadas diferentes taxas de autofecundação e migração, e selecionada a combinação que apresentou valores de heterozigosidade observada e esperada mais próximos dos obtidos com marcadores microssatélites. Com base nas simulações, a autofecundação foi de 0,3 e a taxa de migração variou de 0,5 a 0,6, valores que podem ter conduzido ao aumento da endogamia e deriva genética, resultando em baixa diversidade genética. Recomenda-se a expansão da área e a redução de perturbações para promover a ocorrência de polinizadores, que desempenham um papel importante no aumento da diversidade genética.

Assuntos

RESUMO

ABSTRACT: Mangaba tree is a fruit tree species whose natural populations are fragmented by anthropic actions. For this reason, studies assessing the impact of fragmentation on the diversity and genetic structure of these populations are required in order to establish suitable conservation strategies. In our study, we used data from analyzes through microsatellite markers in computer simulations to estimate the rates of migration and selfing of six mangaba populations. The studied populations are located in the northeastern states of Ceará, Pernambuco and Sergipe. We tested different selfing and migration rates and selected the combination that showed values of observed and expected heterozygosity closest to those previously obtained with microsatellite markers. According to our simulations, selfing and migration were moderate. This may have led to an increase in inbreeding and genetic drift, resulting in low genetic diversity. We recommend expanding the area and reducing disturbance to promote the occurrence of pollinators, which play an important role in increasing genetic diversity.

RESUMO: A mangabeira é uma espécie frutífera cujas populações naturais se encontram fragmentadas por ações antrópicas. Desse modo, são necessários estudos sobre a avaliação do impacto da fragmentação sobre a diversidade e estrutura genética dessas populações para o estabelecimento de estratégias de conservação adequadas. No presente estudo, foram utilizados dados de análises com marcadores microssatélites em simulações computacionais para estimar as taxas de migração e autofecundação de seis populações de mangaba. As populações estudadas estão localizadas nos estados nordestinos do Ceará, Pernambuco e Sergipe. Foram testadas diferentes taxas de autofecundação e migração, e selecionada a combinação que apresentou valores de heterozigosidade observada e esperada mais próximos dos obtidos com marcadores microssatélites. Com base nas simulações, a autofecundação foi de 0,3 e a taxa de migração variou de 0,5 a 0,6, valores que podem ter conduzido ao aumento da endogamia e deriva genética, resultando em baixa diversidade genética. Recomenda-se a expansão da área e a redução de perturbações para promover a ocorrência de polinizadores, que desempenham um papel importante no aumento da diversidade genética.

RESUMO

Individual dietary specialization is one of the factors that promotes variation in resource use at the individual level. Here we used stable isotope analysis of multiple tissues with different turnover rates to examine the degree of individual specialization in two sub-populations of the predator Cichla temensis inhabiting both fragmented and undammed rivers within the Uatumã River basin of the Amazon. Our results showed that the undammed river provides better conditions to promote individual dietary specialization than the fragmented river. This study contributes to the understanding of how specific life history characteristics of populations of generalist predators are impacted by fragmentation within megadiverse environments such as the Amazon basin.

Assuntos