202 research outputs found
Mapeamento preditivo da vegetação: uso de SIG para modelar a distribuição espacial de espécies arbóreas na Amazônia Central
A distribuição espacial das populações vegetais é abordada na ecologia como uma importante questão devido a sua contribuição ao entendimento de padrões e processos em florestas tropicais. A configuração espacial das populações vegetais é afetada pela interação dos fatores bióticos e abióticos do ambiente. Desta forma, a compreensão dos fatores que estruturam as populações vegetais possibilita a elaboração de modelos de distribuição de espécies. Assim, este trabalho teve como objetivo principal elaborar e validar modelos de capazes de predizer a probabilidade de ocorrência de Aniba roseaodora, Cariniana micrantha, Caryocar villosum, Dinizia excelsa, Dipteryx odorata, Goupia glabra, Manilkara bidentata e Manilkara huberi, Parida multifuga, Parkia pendula, Peltogyne paniculata, Pseudopiptadenia psilostachya em função de variáveis topográficas. A probabilidade de ocorrência dessas 12 espécies arbóreas foi estimada a partir de regressão logística múltipla. Os parâmetros estimados foram incorporados a um SIG e com isso foi obtida a representação espacial das probabilidades de ocorrência estimadas para cada uma das espécies. Os modelos indicaram associação entre a ocorrência dos indivíduos em relação à topografia para 10 espécies. Os modelos estimaram de maneira acurada a ocorrência de 9 espécies. A densidade dos indivíduos variou entre as áreas do modelo e de validação. Para área onde o modelo foi validado houve sobreposição entre a distribuição observada e estimada para as 9 espécies citadas anteriormente. No entanto, houve grande variação entre o acréscimo de acerto de ocorrência para essas espécies. Desta forma, o trabalho aqui apresentado indica que modelos preditivos de distribuição de espécies arbóreas podem predizer com acurácia ocorrência de espécies em determinada área, mas que a extrapolação para outras áreas deve considerar outros fatores, além da topografia
Manual de utilização de ferramenta do Centro Comum de Investigação para validação das mudanças da cobertura vegetal e do uso da terra
O projeto TREES-3 do CCI tem como objetivo avaliar mudanças da cobertura vegetal na região tropical que ocorreram entre 1990 e 2000, e entre 2000-(2005)-2010. Para isto, foram processadas e avaliadas mudanças da cobertura vegetal em uma grande quantidade de imagens de satélite multi-temporais de resolução espacial média (unidades amostrais de 20 km x 20 km de imagens Landsat). Desta forma, o projeto TREES-3 busca avaliar para cada uma das unidades amostrais a cobertura florestal e as mudanças da cobertura vegetal ocorrida num quinquénio ou década com a mais alta precisão possível. A análise da mudança da cobertura vegetal e do uso da terra inclui também uma etapa de validação visual da classificação das imagens de satélite para atribuir as classes definitivas. Para esta etapa, o CCI desenvolveu uma ferramenta computacional chamada ‘‘Ferramenta do CCI para validação das mudanças da cobertura vegetal e do uso da terra’’. Esta ferramenta é utilizada por agentes florestais nacionais ou especialistas em sensoriamento remoto provenientes de países tropicais. Nesta ferramenta, a interpretação visual das imagens de satélite é efetuada de maneira simultânea utilizando imagens de dois períodos diferentes. Desta forma, é possível verificar e ajustar classes de uso da terra que foram previamente definidas. Neste trabalho, a FAO colabora com o CCI no âmbito do projeto de levantamento por sensoriamento remoto para avaliação dos recursos florestais mundiais (FRA). O CCI agregou na ferramenta computacional uma função que permite atribuir classes de uso da terra que fazem parte da classificação utilizada pela FAO. O presente documento, intitulado ‘‘Manual de utilização de ferramenta do Centro Comum de Investigação para validação das mudanças da cobertura vegetal e do uso da terra”, explica o procedimento para instalação da ferramenta e descreve as características da interface gráfica do usuário.JRC.H.3-Forest Resources and Climat
Exploring the impact of data curation criteria on the observed geographical distribution of mosses
Biodiversity data records contain inaccuracies and biases. To overcome this limitation and establish robust geographic patterns, ecologists often curate records keeping those that are most suitable for their analyses. Yet, this choice is not straightforward and the outcome of the analysis may vary due to a trade-off between data quality and volume. This problem is particularly recurrent for less-studied groups with patchy sampling effort. The latitudinal pattern of mosses richness remains inconsistent across studies and these may emerge purely from sampling artefacts. Our main objective here is to assess the effect of different curation criteria on this spatial pattern in the Temperate Northern Hemisphere (above 20° latitude). We contrasted the geographical distribution of moss species records and the latitude-species richness relation obtained under different data curation scenarios. These scenarios comprehend five sources of taxonomical standardisations and eight data cleaning filters. The analyses are based on the selection of well-surveyed cells at 100 km cell resolution. The application of some ‘data curation scenarios’ severely affects the number of records selected for analysis and substantially changes the proportion of richness per cell. The sensitivity to data curation becomes detectable at regional and at the cell scales showing a large shift in the latitudinal richness peak in Europe, from 60° N to 45° N latitude, when only preserved specimens are selected and duplicates based on date of collection and coordinates are excluded. Our results stress the importance of justifying the criteria used for filtering biodiversity data retrieved from biodiversity databases to avoid detecting misleading patterns. Curating records under particular criteria compromises the information in some areas displaying different spatial information of mosses. This problem can be ameliorated if data filtering is combined with identifying well-surveyed cells, render relatively constant results under different combinations of filtering even for less well-known groups such as mossesAgencia Estatal de Investigación, Grant/Award Number: MCIN/AEI/10.13039/501100011033, PID2019-106840GB-C21 and PID2019-106840GA-C22; Consejo Superior de Investigaciones Científicas; H2020 Marie Skłodowska-Curie Actions, Grant/Award Number: 843234; Instituto Nacional de Ciência e Tecnologia em Ecologia, Evoluçao e Conservação da Biodiversidade (INCT-EECBio), Grant/Award Number: FAPEG 201810267000023 and MCTIC/CNPq 465610/2014-
Metacommunity patterns of Amazonian Odonata: The role of environmental gradients and major rivers
Background. We identified and classified damselfly (Zygoptera) and dragonfly (Anisoptera) metacommunities in Brazilian Amazonia, relating species distribution patterns to known biological gradients and biogeographical history. We expected a random distribution of both Zygoptera and Anisoptera within interfluves. At the Amazonian scale, we expected Anisoptera metacommunities to be randomly distributed due to their higher dispersal ability and large environmental tolerance. In contrast, we expected Zygoptera communities to exhibit a Clementsian pattern, limited by the large Amazonia rivers due to their low dispersal ability. Methods. We used a dataset of 58 first-to-third order well-sampled streamlets in four Amazonian interfluves and applied an extension of the Elements of Metacommunity Structure (EMS) framework, in which we order Zygoptera and Anisoptera metacommunities by known spatial and biogeographic predictors. Results. At the Amazonian scale, both Zygoptera and Anisoptera presented a Clementsian pattern, driven by the same environmental and biogeographical predictors, namely biogeographic region (interfluve), annual mean temperature, habitat integrity and annual precipitation. At the interfluve scale, results were less consistent and only partially support our hypothesis. Zygoptera metacommunities at Guiana and Anisoptera metacommunities at Tapajós were classified as random, suggesting that neutral processes gain importance at smaller spatial scales. Discussion. Our findings were consistent with previous studies showing that environmental gradients and major rivers limit the distribution of Odonata communities, supporting that larger Amazonian rivers act as barriers for the dispersal of this group. In addition, the importance of habitat integrity indicates that intactness of riparian vegetation is an important filter shaping metacommunity structure of Amazonian stream Odonata.This work was supported by the Coordination for the Improvement of Higher Education Personnel—CAPES (120147/2016-01), Brazil National Council for Scientific and Technological Development—CNPq (303252/2013-8, 574008/2008-0, 305542/2010-9,478884/2008-7, 314523/2014-6), Brazilian Agriculture Research Corporation EMBRAPA (SEG 02.08.06.005.00), the UK Darwin Initiative (17023), The Nature Conservancy and the Natural Environment Research Council—NERC (NE/F01614X/1 and NE/G000816/1)
Metacommunity patterns of Amazonian Odonata: the role of environmental gradients and major rivers
Background We identified and classified damselfly (Zygoptera) and dragonfly (Anisoptera) metacommunities in Brazilian Amazonia, relating species distribution patterns to known biological gradients and biogeographical history. We expected a random distribution of both Zygoptera and Anisoptera within interfluves. At the Amazonian scale, we expected Anisoptera metacommunities to be randomly distributed due to their higher dispersal ability and large environmental tolerance. In contrast, we expected Zygoptera communities to exhibit a Clementsian pattern, limited by the large Amazonia rivers due to their low dispersal ability. Methods We used a dataset of 58 first-to-third order well-sampled streamlets in four Amazonian interfluves and applied an extension of the Elements of Metacommunity Structure (EMS) framework, in which we order Zygoptera and Anisoptera metacommunities by known spatial and biogeographic predictors. Results At the Amazonian scale, both Zygoptera and Anisoptera presented a Clementsian pattern, driven by the same environmental and biogeographical predictors, namely biogeographic region (interfluve), annual mean temperature, habitat integrity and annual precipitation. At the interfluve scale, results were less consistent and only partially support our hypothesis. Zygoptera metacommunities at Guiana and Anisoptera metacommunities at Tapajós were classified as random, suggesting that neutral processes gain importance at smaller spatial scales. Discussion Our findings were consistent with previous studies showing that environmental gradients and major rivers limit the distribution of Odonata communities, supporting that larger Amazonian rivers act as barriers for the dispersal of this group. In addition, the importance of habitat integrity indicates that intactness of riparian vegetation is an important filter shaping metacommunity structure of Amazonian stream Odonata
Recommended from our members
Macroecological links between the Linnean, Wallacean, and Darwinian shortfalls
Species are the currency of most biodiversity studies. However, many shortfalls and biases remain in our
biodiversity estimates, preventing a comprehensive understanding of the eco-evolutionary processes that
have shaped the biodiversity currently available on Earth. Biased biodiversity estimates also jeopardize the effective implementation of data-driven conservation strategies, ultimately leading to biodiversity loss. Here, we delve into the concept of the Latitudinal Taxonomy Gradient (LTG) and show how this new idea provides an interesting conceptual link between the Linnean (i.e., our ignorance of how many species there are on Earth), Darwinian (i.e., our ignorance of species evolutionary relationships), and Wallacean (i.e., our ignorance on species distribution) shortfalls. More specifically, we contribute to an improved understanding of LTGs and establish the basis for the development of new methods that allow us to: (i) better account for the integration between different shortfalls and, (ii) estimate how these interactions may affect our understanding about the evolutionary components of richness gradients at macroecological scales.This manuscript is partially derived from a working group on “Biodiversity Shortfalls” held in November
2019 and sponsored by the National Institutes for Science and Technology (INCT) in Ecology, Evolution, and
Biodiversity Conservation (CNPq proc. 465610/2014-5 and FAPEG proc. 201810267000023). JJMG and LEF are supported by Ph.D. and M.Sc. scholarships from CAPES, while LM and RBP are supported by postdoctoral
fellowships from CAPES (PNPD). JS was funded by the funded by the European Union’s Horizon 2020
research and innovation programme under the Marie Skłodowska-Curie Action (grant agreement #843234;
project: TAXON-TIME) and by the Spanish Council for Scientific Research (IF_ERC). GT and LJ are supported
by a DTI fellowships from CNPq, while JAFD-F, LGL, and CJBC are supported by Productivity Grants from CNPq.Peer reviewe
Variation in stem mortality rates determines patterns of above-ground biomass in Amazonian forests: implications for dynamic global vegetation models
Understanding the processes that determine above-ground biomass (AGB) in Amazonian forests is important for predicting the sensitivity of these ecosystems to environmental change and for designing and evaluating dynamic global vegetation models (DGVMs). AGB is determined by inputs from woody productivity [woody net primary productivity (NPP)] and the rate at which carbon is lost through tree mortality. Here, we test whether two direct metrics of tree mortality (the absolute rate of woody biomass loss and the rate of stem mortality) and/or woody NPP, control variation in AGB among 167 plots in intact forest across Amazonia. We then compare these relationships and the observed variation in AGB and woody NPP with the predictions of four DGVMs. The observations show that stem mortality rates, rather than absolute rates of woody biomass loss, are the most important predictor of AGB, which is consistent with the importance of stand size structure for determining spatial variation in AGB. The relationship between stem mortality rates and AGB varies among different regions of Amazonia, indicating that variation in wood density and height/diameter relationships also influences AGB. In contrast to previous findings, we find that woody NPP is not correlated with stem mortality rates and is weakly positively correlated with AGB. Across the four models, basin-wide average AGB is similar to the mean of the observations. However, the models consistently overestimate woody NPP and poorly represent the spatial patterns of both AGB and woody NPP estimated using plot data. In marked contrast to the observations, DGVMs typically show strong positive relationships between woody NPP and AGB. Resolving these differences will require incorporating forest size structure, mechanistic models of stem mortality and variation in functional composition in DGVMs
Variation in stem mortality rates determines patterns of above-ground biomass in Amazonian forests: implications for dynamic global vegetation models
Understanding the processes that determine above-ground biomass (AGB) in Amazonian forests is important for predicting the sensitivity of these ecosystems to environmental change and for designing and evaluating dynamic global vegetation models (DGVMs). AGB is determined by inputs from woody productivity [woody net primary productivity (NPP)] and the rate at which carbon is lost through tree mortality. Here, we test whether two direct metrics of tree mortality (the absolute rate of woody biomass loss and the rate of stem mortality) and/or woody NPP, control variation in AGB among 167 plots in intact forest across Amazonia. We then compare these relationships and the observed variation in AGB and woody NPP with the predictions of four DGVMs. The observations show that stem mortality rates, rather than absolute rates of woody biomass loss, are the most important predictor of AGB, which is consistent with the importance of stand size structure for determining spatial variation in AGB. The relationship between stem mortality rates and AGB varies among different regions of Amazonia, indicating that variation in wood density and height/diameter relationships also influences AGB. In contrast to previous findings, we find that woody NPP is not correlated with stem mortality rates and is weakly positively correlated with AGB. Across the four models, basin-wide average AGB is similar to the mean of the observations. However, the models consistently overestimate woody NPP and poorly represent the spatial patterns of both AGB and woody NPP estimated using plot data. In marked contrast to the observations, DGVMs typically show strong positive relationships between woody NPP and AGB. Resolving these differences will require incorporating forest size structure, mechanistic models of stem mortality and variation in functional composition in DGVMs
Estimating the global conservation status of more than 15,000 Amazonian tree species
Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened plant species on Earth by 22%. We show that the trends observed in Amazonia apply to trees throughout the tropics, and we predict thatmost of the world’s >40,000 tropical tree species now qualify as globally threatened. A gap analysis suggests that existing Amazonian protected areas and indigenous territories will protect viable populations of most threatened species if these areas suffer no further degradation, highlighting the key roles that protected areas, indigenous peoples, and improved governance can play in preventing large-scale extinctions in the tropics in this century
- …