ABSTRACT
Ecologists have historically quantified fundamental biodiversity patterns, including species-area relationships (SARs) and beta diversity, using observed species counts. However, imperfect detection may often bias derived community metrics and subsequent community models. Although several statistical methods claim to correct for imperfect detection, their performance in species-area and ß-diversity research remains unproven. We examine inaccuracies in the estimation of SARs and ß-diversity parameters that emerge from imperfect detection, and whether such errors can be mitigated using a non-parametric diversity estimator (iNEXT.3D) and Multi-Species Occupancy Models (MSOMs). We simulated 28,350 sampling regimes of 2835 fragmented communities, varying the mean and standard deviation of species detection probabilities, and the number of sampling repetitions. We then quantified the bias, accuracy, and precision of derived estimates of model coefficients for SARs and the effects of patch area on ß-diversity (pairwise Sørensen similarity). Imperfect detection biased estimates of all evaluated parameters, particularly when mean detection probabilities were low, and there were few sampling repetitions. Observed counts consistently underestimated species richness and SAR z-values, and overestimated SAR c-values; iNEXT.3D and MSOMs only partially resolved these biases. iNEXT.3D provided the best estimates of SAR z-values, although MSOM estimates were generally comparable. All three methods accurately estimated pairwise Sørensen similarity in most circumstances, but only MSOMs provided unbiased estimates of the coefficients of models examining covariate effects on ß-diversity. Even when using iNEXT.3D or MSOMs, imperfect detection consistently caused biases in SAR coefficient estimates, calling into question the robustness of previous SAR studies. Furthermore, the inability of observed counts and iNEXT.3D to estimate ß-diversity model coefficients resulted from a systematic, area-related bias in Sørensen similarity estimates. Importantly, MSOMs corrected for these biases in ß-diversity assessments, even in suboptimal scenarios. Nonetheless, as estimator performance consistently improved with increasing sampling repetitions, the importance of appropriate sampling effort cannot be understated.
ABSTRACT
Amazonia's floodplain system is the largest and most biodiverse on Earth. Although forests are crucial to the ecological integrity of floodplains, our understanding of their species composition and how this may differ from surrounding forest types is still far too limited, particularly as changing inundation regimes begin to reshape floodplain tree communities and the critical ecosystem functions they underpin. Here we address this gap by taking a spatially explicit look at Amazonia-wide patterns of tree-species turnover and ecological specialization of the region's floodplain forests. We show that the majority of Amazonian tree species can inhabit floodplains, and about a sixth of Amazonian tree diversity is ecologically specialized on floodplains. The degree of specialization in floodplain communities is driven by regional flood patterns, with the most compositionally differentiated floodplain forests located centrally within the fluvial network and contingent on the most extraordinary flood magnitudes regionally. Our results provide a spatially explicit view of ecological specialization of floodplain forest communities and expose the need for whole-basin hydrological integrity to protect the Amazon's tree diversity and its function.
Subject(s)
Biodiversity , Floods , Rivers , Trees , Brazil , ForestsABSTRACT
Understanding which species will be extirpated in the aftermath of large-scale human disturbance is critical to mitigating biodiversity loss, particularly in hyperdiverse tropical biomes. Deforestation is the strongest driver of contemporary local extinctions in tropical forests but may occur at different tempos. The 2 most extensive tropical forest biomes in South America-the Atlantic Forest and the Amazon-have experienced historically divergent pathways of habitat loss and biodiversity decay, providing a unique case study to investigate rates of local species persistence on a single continent. We quantified medium- to large-bodied mammal species persistence across these biomes to elucidate how landscape configuration affects their persistence and associated ecological functions. We collected occurrence data for 617 assemblages of medium- to large-bodied mammal species (>1 kg) in the Atlantic Forest and the Amazon. Analyzing natural habitat cover based on satellite data (1985-2022), we employed descriptive statistics and generalized linear models (GLMs) to investigate ecospecies occurrence patterns in relation to habitat cover across the landscapes. The subregional erosion of Amazonian mammal assemblage diversity since the 1970s mirrors that observed since the colonial conquest of the Atlantic Forest, given that 52.8% of all Amazonian mammals are now on a similar trajectory. Four out of 5 large mammals in the Atlantic Forest were prone to extirpation, whereas 53% of Amazonian mammals were vulnerable to extirpation. Greater natural habitat cover increased the persistence likelihood of ecospecies in both biomes. These trends reflected a median local species loss 63.9% higher in the Atlantic Forest than in the Amazon, which appears to be moving toward a turning point of forest habitat loss and degradation. The contrasting trajectories of species persistence in the Amazon and Atlantic Forest domains underscore the importance of considering historical habitat loss pathways and regional biodiversity erosion in conservation strategies. By focusing on landscape configuration and identifying essential ecological functions associated with large vertebrate species, conservation planning and management practices can be better informed.
Uso de la pérdida histórica de hábitat para predecir la desaparición de mamíferos contemporáneos en los bosques neotropicales Resumen Tener conocimiento de cuáles especies desaparecerán después de una perturbación humana es de suma importancia para mitigar la pérdida de la biodiversidad, particularmente en los biomas híper diversos. La deforestación es la principal causante de las extinciones locales contemporáneas en los bosques tropicales, aunque puede ocurrir en diferentes tiempos. Los dos bosques tropicales más extensos de América del Sur el Bosque Atlántico y la Amazonia han experimentado formas históricamente divergentes de pérdida de hábitat y decadencia de biodiversidad, lo que proporciona un caso único de estudio para investigar las tasas de persistencia de las especies locales en un solo continente. Cuantificamos la persistencia de las especies de mamíferos de talla mediana a grande en estos dos bosques para aclarar cómo la configuración del paisaje afecta su persistencia y las funciones ecológicas asociadas. Recolectamos datos de presencia de 617 ensambles de especies de mamíferos de talla mediana a grande (>1 kg) en el Bosque Atlántico y en la Amazonia. Analizamos la cobertura natural del hábitat con base en datos satelitales (19852022) y empleamos estadística descriptiva y modelos lineales generalizados (MLG) para investigar los patrones de presencia de las eco especies en relación con la cobertura del hábitat en los distintos paisajes. La erosión subregional de la diversidad de ensambles de mamíferos en la Amazonia desde los 70s es igual a la observada en el Bosque Atlántico desde la conquista colonial, dado que 52.8% de todos los mamíferos amazónicos se encuentran en una trayectoria similar. Cuatro de los cinco grandes mamíferos en el Bosque Atlántico estaban propensos a desaparecer, mientras que el 53% de los mamíferos amazónicos estaban vulnerables a desaparecer. Una mayor cobertura natural del hábitat incrementó la probabilidad de persistencia de las eco especies en ambos bosques. Estas tendencias reflejaron una pérdida mediana de especies locales 63.9% mayor en el Bosque Atlántico que en la Amazonia, lo cual parece dirigirse hacia un momento decisivo para la degradación y pérdida del hábitat del bosque. Las trayectorias contrastantes de la persistencia de especies en el Bosque Atlántico y la Amazonia destacan la importancia de considerar dentro de las estrategias de conservación las maneras en las que se ha perdido históricamente el hábitat y la erosión de la biodiversidad regional. Si nos enfocamos en la configuración del paisaje y en la identificación de las funciones ecológicas esenciales asociadas con las especies grandes de vertebrados, podemos informar de mejor manera a la planeación de la conservación y las prácticas de manejo.
Subject(s)
Biodiversity , Conservation of Natural Resources , Extinction, Biological , Forests , Mammals , Animals , Mammals/physiology , Tropical Climate , Ecosystem , BrazilABSTRACT
Coats-of-arms representing municipal counties express local patterns of rural economics, natural resource and land use, features of the natural capital, and the cultural heritage of either aborigines or colonists. We reconstruct the subnational economic and political timeline of the world's largest tropical country using municipal coats-of-arms to reinterpret Brazil's historical ecology. We assessed all natural resource, biophysical, agricultural, and ethnocultural elements of 5,197 coats-of-arms (93.3%) distributed throughout Brazil. We extracted socioenvironmental co-variables for any municipality to understand and predict the relationships between social inequality, environmental degradation, and the historical ecology symbology. We analyzed data via ecological networks and structural equation models. Our results show that the portfolio of political-administrative symbology in coats-of-arms is an underutilized tool to understand the history of colonization frontiers. Although Brazil is arguably Earth's most species-rich country, generations of political leaders have historically failed to celebrate this biodiversity, instead prioritizing a symbology depicted by icons of frontier conquest and key natural resources. Brazilian historical ecology reflects the relentless depletion of the natural resource capital while ignoring profound social inequalities. Degradation of natural ecosystems is widespread in Brazilian economy, reflecting a legacy of boom-and-bust rural development that so far has failed to deliver sustainable socioeconomic prosperity.
Subject(s)
Conservation of Natural Resources , Ecosystem , Humans , Conservation of Natural Resources/methods , Socioeconomic Factors , Brazil , Rural Population , AgricultureABSTRACT
Abstract The Brazilian state of Acre is located in the southwestern Amazon and it is characterized by a humid tropical forest vegetation that covers plains and mountains. Up to this point, the composition of termite species in the state is not known. The aim of this study was to provide a checklist of termite species or recognizable taxonomic units for the state of Acre. Sampling was conducted through field expeditions at the Serra do Divisor National Park, Chandless State Park, Humaitá Forest Reserve, and Chico Mendes Environmental Park using a standardized rapid termite inventory protocol in the first two areas and active searching collections in the others, without a specific protocol. This study also included occurrence records published in the scientific literature. A total of 128 species and morphospecies of termites were found in Acre, distributed across 59 genera and four families. The most frequently occurring species in Acre was Heterotermes tenuis (Hagen, 1858). The study also identified six new species records for Brazil. The predominant feeding groups were soil-feeders and wood-feeders, as expected from data obtained from surveys in humid tropical forests. Despite the significant number of new records for Acre (112), it is concluded that a larger sampling effort is still required, as many areas of the state have not yet been studied for termites.
Resumen O estado brasileiro do Acre está localizado no sudoeste da Amazônia e é caracterizado por uma vegetação de floresta tropical úmida que cobre planícies e montanhas. Até então, a composição de espécies de térmitas no estado não é conhecida. O objetivo desse estudo foi construir um checklist de espécies ou unidades taxonômicas reconhecíveis de térmitas para o estado do Acre. A amostragem foi conduzida através de expedições de campo no Parque Nacional da Serra do Divisor, no Parque Estadual Chandless, na Reserva Florestal Humaitá, e no Parque Ambiental Chico Mendes utilizando o protocolo rápido de diversidade de térmitas nas duas primeiras áreas e coletas avulsas nas demais, sem um protocolo específico. Este estudo também incluiu registros de ocorrência publicados na literature científica. Um total de 128 espécies e morfoespécies de térmitas foram encontradas no Acre, distribuídas em 59 gêneros e quatro famílias. A espécie de ocorrência mais frequente no Acre foi Heterotermes tenuis (Hagen, 1858). O estudo também identificou seis novos registros de espécies para o Brasil. Os grupos alimentares predominantes foram os humívoros e xilófagos, como esperado a partir de dados obtidos de pesquisas em florestas tropicais úmidas. Apesar do número significativo de novos registros para o Acre (112), conclui-se que ainda é necessário um esforço amostral maior, uma vez que muitas áreas do estado ainda não foram estudadas para térmitas.
ABSTRACT
Mammalian carnivores are considered a key group in maintaining ecological health and can indicate potential ecological integrity in landscapes where they occur. Carnivores also hold high conservation value and their habitat requirements can guide management and conservation plans. The order Carnivora has 84 species from 8 families in the Neotropical region: Canidae; Felidae; Mephitidae; Mustelidae; Otariidae; Phocidae; Procyonidae; and Ursidae. Herein, we include published and unpublished data on native terrestrial Neotropical carnivores (Canidae; Felidae; Mephitidae; Mustelidae; Procyonidae; and Ursidae). NEOTROPICAL CARNIVORES is a publicly available data set that includes 99,605 data entries from 35,511 unique georeferenced coordinates. Detection/non‐detection and quantitative data were obtained from 1818 to 2018 by researchers, governmental agencies, non‐governmental organizations, and private consultants. Data were collected using several methods including camera trapping, museum collections, roadkill, line transect, and opportunistic records. Literature (peerreviewed and grey literature) from Portuguese, Spanish and English were incorporated in this compilation. Most of the data set consists of detection data entries (n = 79,343; 79.7%) but also includes non‐detection data (n = 20,262; 20.3%). Of those, 43.3% also include count data (n = 43,151). The information available in NEOTROPICAL CARNIVORES will contribute to macroecological, ecological, and conservation questions in multiple spatio‐temporal perspectives. As carnivores play key roles in trophic interactions, a better understanding of their distribution and habitat requirements are essential to establish conservation management plans and safeguard the future ecological health of Neotropical ecosystems. Our data paper, combined with other largescale data sets, has great potential to clarify species distribution and related ecological processes within the Neotropics. There are no copyright restrictions and no restriction for using data from this data paper, as long as the data paper is cited as the source of the information used. We also request that users inform us of how they intend to use the data.
ABSTRACT
Standard line-transect census techniques were deployed to generate a checklist and quantify the abundance of medium and large-bodied vertebrate species in forest areas of eastern Amazonia with and without a history of reduced-impact logging (RIL). Three areas were allocated a total of 1,196.9 km of line-transect census effort. Sampling was conducted from April to June 2012 and from April to August 2013, and detected 29 forest vertebrate species considered in this study belonging to 15 orders, 20 families and 28 genera. Additionally, eight species were recorded outside census walks through direct and indirect observations. Of this total, six species are considered vulnerable according to IUCN (Ateles paniscus, Myrmecophaga tridactyla, Priodontes maximus, Tapirus terrestris, Tayassu peccary, Chelonoidis denticulata). Observed species richness ranged from 21 to 24 species in logged and unlogged areas, and encounter rates along transects were highly variable between treatments. However, the relative abundance of species per transect did not differ between transects in logged and unlogged forests. Of the species detected during censuses, only three showed different relative abundance between the two treatments (Saguinus midas, Tinamus spp. and Dasyprocta leporina). Our results show that the effect of RIL forest management was a relatively unimportant determinant of population abundance for most medium and large vertebrates over the time period of the survey.
Técnicas padronizadas de censo por transecções lineares foram empregadas para gerar uma lista e quantificar a abundância de espécies de vertebrados de médio e grande porte em áreas de floresta na Amazônia oriental, com e sem uma história de exploração de impacto reduzido (EIR). Três áreas foram amostradas com um esforço total de 1.196,9 km de censo ao longo de transectos lineares. A amostragem foi realizada de abril-junho de 2012 e de abril-agosto de 2013, e detectou 29 espécies florestais de vertebrados consideradas neste estudo pertencentes a 15 ordens, 20 famílias e 28 gêneros. Adicionalmente, oito espécies foram registradas fora dos censos ao longo dos transectos por meio de observações diretas e indiretas. Desse total, seis espécies são consideradas vulneráveis de acordo com a IUCN (Ateles paniscus, Myrmecophaga tridactyla, Priodontes maximus, Tapirus terrestris, Tayassu pecari, Chelonoidis denticulata). A riqueza das espécies observada variou de 21 a 24 espécies em áreas com e sem corte seletivo, e as taxas de encontro ao longo dos transectos foram bastante variáveis entre os tratamentos. No entanto, a abundância relativa das espécies por transecto não diferiu entre florestas não exploradas e exploradas. Das espécies detectadas durante o censo, apenas três apresentaram diferentes abundâncias relativas entre os dois tratamentos (Saguinus midas, Tinamus spp. e Dasyprocta leporina). Nossos resultados mostram que o efeito do manejo florestal EIR não foi relativamente determinante para abundância populacional da maioria dos vertebrados de médio e grande porte.