Consider both water and land
When designing terrestrial reserves, it is common to consider the needs of species and systems from a terrestrial perspective, with an assumption that any freshwater ...systems will benefit as well. Leal
et al.
tested this assumption by analyzing data from two locations in the Brazilian Amazon and found that it is far from accurate: Terrestrial systems confer little benefit to freshwater systems (see the Perspective by Abell and Harrison). However, the authors also found that integrating the needs of freshwater species into overall reserve planning increased freshwater benefits by 600% while only decreasing terrestrial outcomes by 1%. They argue that reserve planning must take freshwater systems into account if they are to protect across both realms.
Science
, this issue p.
117
; see also p.
38
A study of terrestrial and freshwater species in the Amazon suggests that the conservation needs of freshwater species need to be actively considered.
Conservation initiatives overwhelmingly focus on terrestrial biodiversity, and little is known about the freshwater cobenefits of terrestrial conservation actions. We sampled more than 1500 terrestrial and freshwater species in the Amazon and simulated conservation for species from both realms. Prioritizations based on terrestrial species yielded on average just 22% of the freshwater benefits achieved through freshwater-focused conservation. However, by using integrated cross-realm planning, freshwater benefits could be increased by up to 600% for a 1% reduction in terrestrial benefits. Where freshwater biodiversity data are unavailable but aquatic connectivity is accounted for, freshwater benefits could still be doubled for negligible losses of terrestrial coverage. Conservation actions are urgently needed to improve the status of freshwater species globally. Our results suggest that such gains can be achieved without compromising terrestrial conservation goals.
Secondary forests (SFs) regenerating on previously deforested land account for large, expanding areas of tropical forest cover. Given that tropical forests rank among Earth’s most important ...reservoirs of carbon and biodiversity, SFs play an increasingly pivotal role in the carbon cycle and as potential habitat for forest biota. Nevertheless, their capacity to regain the biotic attributes of undisturbed primary forests (UPFs) remains poorly understood. Here, we provide a comprehensive assessment of SF recovery, using extensive tropical biodiversity, biomass, and environmental datasets. These data, collected in 59 naturally regenerating SFs and 30 co‐located UPFs in the eastern Amazon, cover >1,600 large‐ and small‐stemmed plant, bird, and dung beetles species and a suite of forest structure, landscape context, and topoedaphic predictors. After up to 40 years of regeneration, the SFs we surveyed showed a high degree of biodiversity resilience, recovering, on average among taxa, 88% and 85% mean UPF species richness and composition, respectively. Across the first 20 years of succession, the period for which we have accurate SF age data, biomass recovered at 1.2% per year, equivalent to a carbon uptake rate of 2.25 Mg/ha per year, while, on average, species richness and composition recovered at 2.6% and 2.3% per year, respectively. For all taxonomic groups, biomass was strongly associated with SF species distributions. However, other variables describing habitat complexity—canopy cover and understory stem density—were equally important occurrence predictors for most taxa. Species responses to biomass revealed a successional transition at approximately 75 Mg/ha, marking the influx of high‐conservation‐value forest species. Overall, our results show that naturally regenerating SFs can accumulate substantial amounts of carbon and support many forest species. However, given that the surveyed SFs failed to return to a typical UPF state, SFs are not substitutes for UPFs.
Housing much of Earth’s carbon and biodiversity, tropical forests are, arguably, our planet’s most important ecosystems. Yet, humanity is destroying tropical primary forests at an alarming rate. Mitigating this is the expansion of secondary forests (SFs). However, SF conservation value is controversial and hotly debated. We show that SFs can accumulate large amounts of carbon and support many forest‐dependent species but that they do not attain the characteristics of undisturbed primary forests (UPFs), even after several decades of succession. As such, SFs are not substitutes for UPFs.
Quantifying the impact of habitat disturbance on ecosystem function is critical to understanding and predicting the future of tropical forests. Many studies have examined post‐disturbance changes in ...animal traits related to mutualistic interactions with plants, but the effect of disturbance on plant traits in diverse forests has received much less attention.
Focusing on two study regions in the eastern Brazilian Amazon, we used a trait‐based approach to examine how seed dispersal functionality within tropical plant communities changes across a landscape‐scale gradient of human modification, including both regenerating secondary forests and primary forests disturbed by burning and selective logging.
Surveys of 230 forest plots recorded 26,533 live stems from 846 tree species. Using herbarium material and literature, we compiled trait information for each tree species, focusing on dispersal mode and seed size.
Disturbance reduced tree diversity and increased the proportion of lower wood density and small‐seeded tree species in study plots. Disturbance also increased the proportion of stems with seeds that are ingested by animals and reduced those dispersed by other mechanisms (e.g. wind). Older secondary forests had functionally similar plant communities to the most heavily disturbed primary forests. Mean seed size and wood density per plot were positively correlated for plant species with seeds ingested by animals.
Synthesis. Anthropogenic disturbance has major effects on the seed traits of tree communities, with implications for mutualistic interactions with animals. The important role of animal‐mediated seed dispersal in disturbed and recovering forests highlights the need to avoid defaunation or promote faunal recovery. The changes in mean seed width suggest larger vertebrates hold especially important functional roles in these human‐modified forests. Monitoring fruit and seed traits can provide a valuable indicator of ecosystem condition, emphasizing the importance of developing a comprehensive plant traits database for the Amazon and other biomes.
Sumário
Para melhor entender e prever o futuro das florestas tropicais é crítico quantificar o impacto de distúrbios antrópicos sobre as funções ecossistêmicas. Muitos estudos já avaliaram, após eventos de distúrbios, mudanças nas características funcionais da fauna relacionadas com interações mutualísticas com a flora. Porém, o efeito de distúrbios antrópicos nas características funcionais da comunidade arbórea de florestas megadiversas é ainda pouco estudado.
Este estudo focou em duas regiões distintas da Amazônia oriental brasileira, e utilizou um método baseado em características funcionais para entender como a dispersão de sementes, dentro de comunidades arbóreas, pode ser modificada ao longo de um gradiente de distúrbio antrópico, incluindo florestas secundárias e florestas primárias afetadas por fogo e corte seletivo.
Foram conduzidos inventários florestais em 230 parcelas de estudo, amostrando um total de 26.533 indivíduos vivos pertencentes a 846 espécies arbóreas. A partir de material depositado em herbários e informações da literatura, as características funcionais, para cada espécie arbórea, foram compiladas, focando no tipo de dispersão e no tamanho da semente.
Os distúrbios antrópicos reduziram a diversidade arbórea e aumentaram a proporção tanto de espécies com baixa densidade de madeira, como de espécies com sementes pequenas. Os distúrbios antrópicos também aumentaram a proporção de árvores com sementes que são ingeridas por animais e diminuíram àquelas dispersas por outros mecanismos, como o vento. Florestas secundárias em estágios mais avançados de sucessão apresentaram comunidades arbóreas funcionalmente semelhantes àquelas de florestas primárias com maior grau de distúrbios antrópicos. A nível de parcela, o tamanho médio das sementes e a densidade da madeira foram positivamente correlacionados para plantas com sementes dispersas por animais.
Síntese: Os distúrbios antrópicos influenciaram amplamente as características funcionais de sementes das comunidades arbóreas, com implicações diretas para as relações mutualísticas com a fauna. A elevada importância de animais na dispersão de sementes tanto em florestas primárias que sofreram distúrbios antrópicos assim como em florestas secundárias ressalta a importância de se evitar a defaunação e de promover a recuperação da fauna. As mudanças no tamanho médio da largura da semente sugerem que grandes vertebrados tem um papel funcional especialmente importante em florestas antropizadas. O monitoramento de características funcionais de frutos e sementes pode prover um valioso indicador das condições de ecossistemas, enfatizando a importância da criação de uma base de dados compreensiva para a Amazônia e para outros biomas contendo características funcionais da vegetação.
Anthropogenic disturbance has major effects on the seed traits of tree communities, with implications for mutualistic interactions with animals. The important role of animal‐mediated seed dispersal in disturbed and recovering forests highlights the need to avoid defaunation or promote faunal recovery. The changes in mean seed width suggest larger vertebrates hold especially important functional roles in these human‐modified forests. Monitoring fruit and seed traits can provide a valuable indicator of ecosystem condition, emphasizing the importance of developing a comprehensive plant traits database for the Amazon and other biomes.
•Odonata order contains distinct species groups that share similar responses to environmental change.•Response patterns were related to phylogeny structure and morphology similarity.•The mentioned ...above relationship appears to be complex and no clear.•We believe that other factors as land use historical can effect these Odonata.•Despite this the response patterns had presented some differences between the areas.
A range of factors may determine the structure of ecological communities in time and space, in particular niches, dispersal limits, and the evolutionary history of the species. In the last decades, the traditional focus of community ecology on species diversity and composition have been supplemented by approaches incorporating functional traits and phylogeny. Following this perspective, we evaluated the response pattern of adult damselflies and dragonflies (Odonata) along a gradient of environmental disturbance in Brazilian Amazonia, with the objective of identifying subgroups of species that respond in a similar manner to environmental filters. The study tested the hypothesis that the subgroups of species with similar responses to the environmental gradient are structured phylogenetically and will be morphologically more similar to one another than they are to the other species. Adult odonates were sampled in 98 Amazonian streams, 48 in the region of Santarém and Belterra and 50 in the municipality of Paragominas, both located in the Brazilian state of Pará. The study was based on an ecological niche modeling approach and statistical significance testing methods to identify groups of species. These species groups (latent classes) were then associated with their morphological characteristics (Abdomen Length and Thorax Length) and phylogenetic relationships. Four latent classes, containing 34 species, were generated for each region. The latent classes of the Odonata formed along the gradient of anthropogenic impact had effects of phylogenetic proximity and the species' morphological similarity. Therefore, species belonging to the same latent class are more morphologically similar and have greater similarities in evolutionary history. It seems likely, however, that other processes may be important for the understanding of the structuring of the latent classes, such as intra- and interspecific relationships, environmental plasticity, and the history of land use. Both morphology and phylogeny are important for understanding species' responses to environmental gradients.
► Uncertainty regarding the future availability and ecological condition of sites is an intrinsic component of conservation planning. ► We analyse how these sources of uncertainty affect the choice ...between short and long conservation contracts. ► Short contracts are optimal if sites will likely remain available for conservation whereas long contracts are optimal when future site availability is unlikely. ► Uncertainty over future ecological conditions has little effect on contract selection. ► In some circumstances, a portfolio of different contract lengths offers greater rewards than uniformly using a single contract duration.
Acquisition of land rights has become a primary tool used to protect terrestrial biodiversity. Fixed length contracts are often used when trying to secure conservation benefits on private land in agri-environment schemes and payment for environmental services schemes, but the duration of the conservation contracts used in different programmes varies. To date, very little research has been undertaken to determine the situations in which contracts of differing lengths are optimal or when conservation agencies or groups should use a portfolio of different contract lengths rather than relying on a single type. Using stochastic dynamic programming and related heuristic methods, we investigate how the choice between short or long conservation contracts is affected by uncertainty regarding the future availability of sites and their ecological condition. We also examine the benefits offered by using a portfolio of different contract lengths. Conservation agencies must pay private landowners a premium to secure longer agreements and because of this, shorter contracts are advantageous if sites are likely to remain available for conservation in the future. Long contracts are preferred when future site availability becomes more unlikely. In contrast to uncertainty over site availability, uncertainty over future ecological conditions has little effect on contract selection and only markedly influences the choice between short and long contracts when there is heterogeneity across sites in expected conservation outcomes and future availability of sites is also uncertain. Finally, when future site availability is unlikely, the use of a portfolio of short and long contracts would offer greater conservation gains than using either type in isolation, even though this option is not yet one that is commonly found in conservation practice.
In negotiations over land-right acquisitions, landowners have an informational advantage over conservation groups because they know more about the opportunity costs of conservation measures on their ...sites. This advantage creates the possibility that landowners will demand payments greater than the required minimum, where this minimum required payment is known as the landowner's willingness to accept (WTA). However, in recent studies of conservation costs, researchers have assumed landowners will accept conservation with minimum payments. We investigated the ability of landowners to demand payments above their WTA when a conservation group has identified multiple sites for protection. First, we estimated the maximum payment landowners could potentially demand, which is set when groups of landowners act as a cooperative. Next, through the simulation of conservation auctions, we explored the amount of money above landowners' WTA (i.e., surplus) that conservation groups could cede to secure conservation agreements, again investigating the influence of landowner cooperatives. The simulations showed the informational advantage landowners held could make conservation investments up to 42% more expensive than suggested by the site WTAs. Moreover, all auctions resulted in landowners obtaining payments greater than their WTA; thus, it may be unrealistic to assume landowners will accept conservation contracts with minimum payments. Of particular significance for species conservation, conservation objectives focused on overall species richness, which therefore recognize site complementarity, create an incentive for landowners to form cooperatives to capture surplus. To the contrary, objectives in which sites are substitutes, such as the maximization of species occurrences, create a disincentive for cooperative formation. En negociaciones sobre adquisición de derechos de tierras, los propietarios tienen una ventaja informativa sobre los grupos de conservación porque conocen más sobre los costos de oportunidad de las medidas de conservación en sus propiedades. Esta ventaja crea la posibilidad de que los propietarios demanden pagos mayores al mínimo requerido, donde este pago mínimo requerido es conocido como la disponibilidad de los propietarios a aceptar (DPA). Sin embargo, en estudios recientes de costos de conservación, los investigadores han asumido que los propietarios aceptarán la conservación con pagos mínimos. Investigamos la habilidad de los propietarios para demandar pagos por arriba de su DPA cuando un grupo de conservación ha identificado múltiples sitios para ser protegidos. Primero, estimamos el pago máximo que los propietarios potencialmente demandarían, el cual es fijado cuando grupos de propietarios actúan como una cooperativa. Posteriormente, mediante la simulación de subastas de conservación, exploramos la cantidad de dinero por arriba de la DPA (i.e., excedente) que los grupos de conservación podrían ceder para asegurar acuerdos de conservación, otra vez investigando la influencia de las cooperativas de propietarios. Las simulaciones mostraron que la ventaja informativa de los propietarios podía hacer que las inversiones fueran hasta 42% más caras que lo sugerido por las DPA. Mas aun, todas las subastas resultaron en que los propietarios obtenían mayores pagos que sus DPA; por lo tanto, puede ser irreal asumir que los propietarios aceptarán contratos de conservación con pagos mínimos. De particular significado para la conservación de especies, los objetivos de conservación fueron enfocados en la riqueza de especies total, lo cual por lo tanto reconoce la complementariedad del sitio, crea un incentivo para que los propietarios formen cooperativas para capturar excedentes. Al contrario, objetivos en los que los sitios son sustitutos, como la maximización de la ocurrencia de especies, son desmotivadores para la cooperación.
Spatially heterogeneous costs of securing conservation agreements should be accounted for when prioritizing properties for conservation investment. Most researchers incorporating conservation costs ...into analyses have relied on estimates of landowners' opportunity costs of accepting a conservation agreement. Implicitly assumed in such studies is therefore that those who “produce” biodiversity (landowners) receive none of the surplus available from trade. Instead, landowners could use their bargaining power to gain profits from conservation investments. We employ game theory to determine the surplus landowners could obtain in negotiations over conservation agreements, and the consequent effects on conservation outcomes, when enrolment decisions are governed by continuous variables (e.g. the proportion of a property to enrol). In addition, we consider how landowner uncertainty regarding the opportunity costs of other landowners affects these outcomes. Landowners' ability to gain surplus is highly variable and reflects variation in the substitutability of different properties for achieving a specified conservation objective. The ability of landowners to obtain profits from conservation agreements results in conservation outcomes that are substantially diminished relative to when landowners accept investment at opportunity costs. Uncertainty increases landowner profits, leading to a greater diminution in conservation benefits.
•Conservation planning studies rely on estimates of landowners' opportunity costs.•This implies that landowners will receive no surplus from conservation contracts.•However, landowners could use their bargaining power to gain surplus in negotiations.•We use game theory to estimate the surplus landowners could gain.•Landowner surplus is highly variable and reflects differences in site substitutability.
Voluntary conservation agreements are commonly used to stem the impact of habitat destruction and degradation on terrestrial biodiversity. Past studies that aim to inform how resources for ...conservation should be allocated across land parcels have assumed the costs of securing conservation on sites can be estimated solely on the basis of the value of alternative land uses. However, in a voluntary negotiation, a landowner could hold-out for a higher payment based on a conservation group or agency’s willingness-to-pay by leveraging the value of biodiversity on the property. We examine landowners’ ability to leverage and the consequences for conservation planning. To explore this, we first use an analytical approximation that simplifies the situation to one where a conservation group prioritizes one site for acquisition. Landowners’ ability to hold-out for higher payments in this situation ranges from approximately 17% to 55% of the value of alternative land uses on the site. We show that landowners’ ability to hold-out for higher payments is more sensitive to variance in the value of alternative land uses than variance in the biodiversity value across properties and is highest when the two factors negatively covary. Next, we consider multi-site selection decisions accounting for community complementarity across parcels. We find that leverage potential can be significantly higher in this context, with a maximum increase of 237% of the value of alternative land uses, and that community irreplaceability is correlated with landowners’ ability to leverage. If one landowner holds out for a higher payment, it has implications for what other parcels should be priorities for protection.
•Above 300 mm of monthly precipitation, leaf litterfall becomes independent of rainfall.•Leaf-litter production is generally insensitive to past human disturbance.•El Niño-fire-affected forests ...present a greater change in leaf-litter production than El Niño-drought-affected forests.
Leaf-litter production is an essential part of the carbon cycle of tropical forests. In the Amazon, it is influenced by climate, presenting high levels during the driest months of the year. However, it is less established how extreme climatic events may impact leaf-litter production in the long term. Even more unclear is how litter production is affected by human-driven disturbances. Here we examine the effects of the 2015–16 El Niño drought and subsequent fires in the leaf-litter production of human-modified Amazonian forests, thus investigating the interactions of a climatic extreme with anthropogenic disturbances on this key process of the Amazonian carbon cycle. We sampled leaf litter from April 2015 until March 2019 across 20 plots located in the eastern Brazilian Amazon, in a total of 11,548 samples. Plots were distributed along a pre-El Niño gradient of human disturbance, including undisturbed, logged, logged-and-burned, and secondary forests. All plots were impacted by the extreme drought caused by the 2015–16 El Niño, and eight were also impacted by understory fires. We found a significant and non-linear relationship between precipitation and monthly leaf-litter production – above 300 mm of monthly precipitation, the production of leaf-litter becomes independent of rainfall. Surprisingly, this relationship was not influenced by pre-El Niño forest disturbance class. During the El Niño, leaf-litter production was higher, decreasing sharply in the following year, especially in El Niño-fire-affected forests. Between 2017 and 2019, all forests experienced a gradual increase in the production of leaf litter. However, the mechanisms behind this increase remain unclear and are likely different between forests affected only by the El Niño drought and those affected by both the drought and fires. Our results suggest that while leaf-litter production may be insensitive to past human disturbances, it is affected, in the short term, by extreme climatic events, especially in forests impacted by El Niño fires.
Wildfires produce substantial CO₂ emissions in the humid tropics during El Niño-mediated extreme droughts, and these emissions are expected to increase in coming decades. Immediate carbon emissions ...from uncontrolled wildfires in human-modified tropical forests can be considerable owing to high necromass fuel loads. Yet, data on necromass combustion during wildfires are severely lacking. Here, we evaluated necromass carbon stocks before and after the 2015–2016 El Niño in Amazonian forests distributed along a gradient of prior human disturbance. We then used Landsat-derived burn scars to extrapolate regional immediate wildfire CO₂ emissions during the 2015–2016 El Niño. Before the El Niño, necromass stocks varied significantly with respect to prior disturbance and were largest in undisturbed primary forests (30.2 ± 2.1 Mg ha⁻¹, mean ± s.e.) and smallest in secondary forests (15.6 ± 3.0 Mg ha⁻¹). However, neither prior disturbance nor our proxy of fire intensity (median char height) explained necromass losses due to wildfires. In our 6.5 million hectare (6.5 Mha) study region, almost 1 Mha of primary (disturbed and undisturbed) and 20 000 ha of secondary forest burned during the 2015–2016 El Niño. Covering less than 0.2% of Brazilian Amazonia, these wildfires resulted in expected immediate CO₂ emissions of approximately 30 Tg, three to four times greater than comparable estimates from global fire emissions databases. Uncontrolled understorey wildfires in humid tropical forests during extreme droughts are a large and poorly quantified source of CO₂ emissions.
This article is part of a discussion meeting issue 'The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications'.
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