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1.
Ecol Lett ; 27(10): e14529, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39388200

RESUMEN

The rise in species richness with area is one of the few ironclad ecological relationships. Yet, little is known about the spatial scaling of alternative dimensions of diversity. Here, we provide empirical evidence for a relationship between the richness of acoustic traits emanating from a landscape, or soundscape richness, and island area, which we term the SoundScape-Area Relationship (SSAR). We show a positive relationship between the gamma soundscape richness and island area. This relationship breaks down at the smallest spatial scales, indicating a small-island effect. Moreover, we demonstrate a positive spatial scaling of the plot-scale alpha soundscape richness, but not the beta soundscape turnover, suggesting a direct effect of species on acoustic trait diversity. We conclude that the general scaling of biodiversity can be extended into the realm of ecoacoustics, implying soundscape metrics are sensitive to fundamental ecological patterns and useful in disentangling their complex mechanistic drivers.


Asunto(s)
Biodiversidad , Acústica , Ecosistema , Islas , Animales , Sonido
2.
Conserv Biol ; : e14414, 2024 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-39466005

RESUMEN

The urgent need to mitigate and adapt to climate change necessitates a comprehensive understanding of carbon cycling dynamics. Traditionally, global carbon cycle models have focused on vegetation, but recent research suggests that animals can play a significant role in carbon dynamics under some circumstances, potentially enhancing the effectiveness of nature-based solutions to mitigate climate change. However, links between animals, plants, and carbon remain unclear. We explored the complex interactions between defaunation and ecosystem carbon in Earth's most biodiverse and carbon-rich biome, tropical rainforests. Defaunation can change patterns of seed dispersal, granivory, and herbivory in ways that alter tree species composition and, therefore, forest carbon above- and belowground. Most studies we reviewed show that defaunation reduces carbon storage 0-26% in the Neo- and Afrotropics, primarily via population declines in large-seeded, animal-dispersed trees. However, Asian forests are not predicted to experience changes because their high-carbon trees are wind dispersed. Extrapolating these local effects to entire ecosystems implies losses of ∼1.6 Pg CO2 equivalent across the Brazilian Atlantic Forest and 4-9.2 Pg across the Amazon over 100 years and of ∼14.7-26.3 Pg across the Congo basin over 250 years. In addition to being hard to quantify with precision, the effects of defaunation on ecosystem carbon are highly context dependent; outcomes varied based on the balance between antagonist and mutualist species interactions, abiotic conditions, human pressure, and numerous other factors. A combination of experiments, large-scale comparative studies, and mechanistic models could help disentangle the effects of defaunation from other anthropogenic forces in the face of the incredible complexity of tropical forest systems. Overall, our synthesis emphasizes the importance of-and inconsistent results when-integrating animal dynamics into carbon cycle models, which is crucial for developing climate change mitigation strategies and effective policies.


Impactos de la defaunación sobre el balance de carbono en los bosques tropicales La urgencia por mitigar y adaptarse al cambio climático requiere que se entiendan las dinámicas del ciclo del carbono. Es común que los modelos del ciclo del carbono se enfoquen en la vegetación, pero estudios recientes sugieren que los animales pueden tener un papel significativo en las dinámicas del carbono bajo ciertas circunstancias, lo que tiene el potencial para mejorar la efectividad de las soluciones basadas en la naturaleza para mitigar el cambio climático. Sin embargo, todavía no está clara la relación entre los animales, las plantas y el carbono. Exploramos las interacciones complejas entre la defaunación y el carbono ambiental en el bioma más biodiverso y más rico en carbono de la Tierra: los bosques tropicales. La defaunación puede cambiar los patrones de dispersión de semillas, granivoría y herbivoría de manera que alteran la composición de especies de árboles y, por lo tanto, el carbono boscoso encima y debajo de la tierra. La mayoría de los estudios que revisamos muestran que la defaunación reduce el almacenamiento de carbono 0­26% en las zonas neotropical y afrotropical, principalmente por medio de las declinaciones poblacionales de los árboles con semillas grandes dispersadas por animales. Sin embargo, no hay pronósticos de que los bosques asiáticos sufran cambios porque sus árboles de carbono alto tienen dispersión por viento. Si extrapolamos estos efectos locales a ecosistemas completos, hay una pérdida explícita equivalente de ∼1.6 Pg CO2 en el Bosque Atlántico Brasileño y de 4 ­ 9.2 Pg en la Amazonia a lo largo de cien años; la pérdida es de ∼14.7 ­ 26.3 Pg en la cuenca del Congo a lo largo de 250 años. Además de que son difíciles de cuantificar con precisión, los efectos de la defaunación sobre el carbono ambiental dependen en gran parte del contexto; los resultados variaron con base en el balance entra las interacciones de las especies mutualistas y antagonistas, las condiciones abióticas, la presión antropogénica y muchos factores más. Una combinación de experimentos, estudios comparativos a gran escala y modelos mecánicos podrían ayudar a comprender los efectos de la defaunación causada por otras fuerzas antropogénicas de frente a la increíble complejidad de los sistemas de bosques tropicales. En general, nuestra síntesis resalta la importancia de ­ y los resultados inconstantes cuando ­ la integración de las dinámicas animales en los modelos del ciclo del carbono, lo cual es importante para desarrollar estrategias de mitigación del cambio climático y políticas efectivas.

3.
Ecol Evol ; 14(7): e70017, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38988344

RESUMEN

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.

5.
Conserv Biol ; 38(4): e14245, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38456548

RESUMEN

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.


Asunto(s)
Biodiversidad , Conservación de los Recursos Naturales , Extinción Biológica , Bosques , Mamíferos , Animales , Mamíferos/fisiología , Clima Tropical , Ecosistema , Brasil
6.
Nat Ecol Evol ; 8(5): 901-911, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38467713

RESUMEN

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.


Asunto(s)
Biodiversidad , Inundaciones , Ríos , Árboles , Brasil , Bosques
8.
Ecol Evol ; 13(12): e10772, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38077521

RESUMEN

The fragmentation and degradation of otherwise continuous natural landscapes pose serious threats to the health of animal populations, consequently impairing their fitness and survival. While most fragmentation ecology studies focus on habitat remnants embedded withinn terrestrial matrices, the effects of true insularization remains poorly understood. Land-bridge islands created by major dams leads to habitat loss and fragmentation, negatively affecting terrestrial biodiversity. To assess the effects of insularization, we conducted a study on the key aspects of dung beetle physiological condition and body size throughout the Balbina Hydroelectric Reservoir located in the Central Amazon. We assessed these traits at the population and assemblage levels, collecting dung beetles from both forest islands and continuous forest areas while analyzing various landscape variables. We show that landscapes with higher forest cover positively affected dung beetle body size. Interestingly, dung beetle responses to insularization were species-dependent; larger islands tended to host larger individuals of Deltochilum aspericole, while in Canthon triangularis, smaller islands showed larger body sizes. However, individuals from the mainland were larger than those from the islands. Moreover, the proportion of closed-canopy forest in the landscapes also impacted physiological attributes. It negatively affected the body size of Deltochilum aspericole and the lipid mass of Dichotomius boreus, but positively affected the lipid mass of Canthon triangularis. These findings contribute to a better understanding of how habitat fragmentation in aquatic matrices affects the size structure and physiology of insect assemblages. This is essential in formulating effective conservation strategies for preserving biodiversity loss in tropical forest regions and mitigating the consequences of hydropower infrastructure.

9.
An Acad Bras Cienc ; 95(suppl 2): e20220746, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38126433

RESUMEN

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.


Asunto(s)
Conservación de los Recursos Naturales , Ecosistema , Humanos , Conservación de los Recursos Naturales/métodos , Factores Socioeconómicos , Brasil , Población Rural , Agricultura
10.
Ecol Evol ; 13(10): e10624, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37869432

RESUMEN

Agricultural commodity production is one the main drivers of deforestation in Legal Brazilian Amazonia resulting in a deforested and/or fragmented landscape formed by forest remnants of different sizes and shape embedded within the agricultural matrix. As an ecosystem engineer and a crucial seed predator, white-lipped peccaries (Tayassu pecari) play a pivotal role in forest structure, biodiversity, and nutrient cycling. However, they are highly sensitive to habitat fragmentation and hunting pressure. White-lipped peccaries are, therefore, a wide-ranging "landscape species," the spatial and ecological requirements of which can be used to guide conservation planning in human-modified landscapes. Using data from GPS-tracked individuals in large-scale mechanized agriculture landscapes in the state of Mato Grosso, Brazil's largest soybean and maize producer, we investiated the home range size and resource selection during both the crop and non-crop season. We observed a seasonal variation in home range size and an increased selection for croplands during the crop season. White-lipped peccaries favored native vegetation patches and also exhibited avoidance of locations distant from perennial water bodies and distant cropland locations far from forest remmants. This study can contribute to inform effective conservation strategies and land management practices aimed at preserving suitable habitats and promoting wildlife coexistence with working agricultural landscapes.

11.
Biol Rev Camb Philos Soc ; 98(5): 1829-1844, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37311559

RESUMEN

In many disturbed terrestrial landscapes, a subset of native generalist vertebrates thrives. The population trends of these disturbance-tolerant species may be driven by multiple factors, including habitat preferences, foraging opportunities (including crop raiding or human refuse), lower mortality when their predators are persecuted (the 'human shield' effect) and reduced competition due to declines of disturbance-sensitive species. A pronounced elevation in the abundance of disturbance-tolerant wildlife can drive numerous cascading impacts on food webs, biodiversity, vegetation structure and people in coupled human-natural systems. There is also concern for increased risk of zoonotic disease transfer to humans and domestic animals from wildlife species with high pathogen loads as their abundance and proximity to humans increases. Here we use field data from 58 landscapes to document a supra-regional phenomenon of the hyperabundance and community dominance of Southeast Asian wild pigs and macaques. These two groups were chosen as prime candidates capable of reaching hyperabundance as they are edge adapted, with gregarious social structure, omnivorous diets, rapid reproduction and high tolerance to human proximity. Compared to intact interior forests, population densities in degraded forests were 148% and 87% higher for wild boar and macaques, respectively. In landscapes with >60% oil palm coverage, wild boar and pig-tailed macaque estimated abundances were 337% and 447% higher than landscapes with <1% oil palm coverage, respectively, suggesting marked demographic benefits accrued by crop raiding on calorie-rich food subsidies. There was extreme community dominance in forest landscapes with >20% oil palm cover where two pig and two macaque species accounted for >80% of independent camera trap detections, leaving <20% for the other 85 mammal species >1 kg considered. Establishing the population trends of pigs and macaques is imperative since they are linked to cascading impacts on the fauna and flora of local forest ecosystems, disease and human health, and economics (i.e., crop losses). The severity of potential negative cascading effects may motivate control efforts to achieve ecosystem integrity, human health and conservation objectives. Our review concludes that the rise of native generalists can be mediated by specific types of degradation, which influences the ecology and conservation of natural areas, creating both positive and detrimental impacts on intact ecosystems and human society.


Asunto(s)
Conservación de los Recursos Naturales , Ecosistema , Animales , Humanos , Porcinos , Bosques , Biodiversidad , Animales Salvajes , Sus scrofa
12.
Ecol Evol ; 13(4): e9975, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-37038515

RESUMEN

Species relative abundance (SRA) is an essential attribute of biotic communities, which can provide an accurate description of community structure. However, the sampling method used may have a direct influence on SRA quantification, since the use of attractants (e.g., baits, light, and pheromones) can introduce additional sources of variation in trap performance. We tested how sampling aided by baits affect community data and therefore alter derived metrics. We tested our hypothesis on dung beetles using data from flight interception traps (FITs) as a baseline to evaluate baited pitfall trap performance. Our objective was to assess the effect of bait attractiveness on estimates of SRA and assemblage metrics when sampled by pitfall traps baited with human feces.Dung beetles were sampled at three terra firme primary forest sites in the Brazilian Amazon. To achieve our objective, we (i) identified species with variable levels of attraction to pitfall baited with human feces; (ii) assessed differences in SRA; and (iii) assessed the effect of bait on the most commonly used diversity metrics derived from relative abundance (Shannon and Simpson indices). We identified species less and highly attracted to the baits used, because most attracted species showed greater relative abundances within baited pitfall traps samples compared with our baseline. Assemblages sampled by baited pitfall traps tend to show lower diversity and higher dominance than those sampled by unbaited FITs. Our findings suggest that for ecological questions focused on species relative abundance, baited pitfall traps may lead to inaccurate conclusions regarding assemblage structure. Although tested on dung beetles, we suggest that the same effect could be observed for other insect taxa that are also sampled with baited traps. We highlight a need for further studies on other groups to elucidate any potential effects of using baits.

14.
Sci Rep ; 13(1): 4464, 2023 03 17.
Artículo en Inglés | MEDLINE | ID: mdl-36932174

RESUMEN

Apex predators typically affect the distribution of key soil and vegetation nutrients through the heterogeneous deposition of prey carcasses and excreta, leading to a nutrient concentration in a hotspot. The exact role of central-place foragers, such as tropical raptors, in nutrient deposition and cycling, is not yet known. We investigated whether harpy eagles (Harpia harpyja) in Amazonian Forests-a typically low soil fertility ecosystem-affect soil nutrient profiles and the phytochemistry around their nest-trees through cumulative deposition of prey carcasses and excreta. Nest-trees occurred at densities of 1.5-5.0/100 km2, and each nest received ~ 102.3 kg of undressed carcasses each year. Effects of nests were surprisingly negative over local soil nutrient profiles, with soils underneath nest-trees showing reductions in nutrients compared with controls. Conversely, canopy tree leaves around nests showed significant 99%, 154% and 50% increases in nitrogen, phosphorus and potassium, respectively. Harpy eagles have experienced a 41% decline in their range, and many raptor species are becoming locally extirpated. These are general examples of disruption in biogeochemical cycles and nutrient heterogeneity caused by population declines in a central-place apex predator. This form of carrion deposition is by no means an exception since several large raptors have similar habits.


Asunto(s)
Ecosistema , Bosques , Árboles , Suelo , Nitrógeno , Clima Tropical
15.
Commun Biol ; 6(1): 132, 2023 02 15.
Artículo en Inglés | MEDLINE | ID: mdl-36792802

RESUMEN

Jaguars (Panthera onca) exert critical top-down control over large vertebrates across the Neotropics. Yet, this iconic species have been declining due to multiple threats, such as habitat loss and hunting, which are rapidly increasing across the New World tropics. Based on geospatial layers, we extracted socio-environmental variables for 447 protected areas across the Brazilian Amazon to identify those that merit short-term high-priority efforts to maximize jaguar persistence. Data were analyzed using descriptive statistics and comparisons of measures of central tendency. Our results reveal that areas containing the largest jaguar densities and the largest estimated population sizes are precisely among those confronting most anthropogenic threats. Jaguars are threatened in the world's largest tropical forest biome by deforestation associated with anthropogenic fires, and the subsequent establishment of pastures. By contrasting the highest threats with the highest jaguar population sizes in a bivariate plot, we provide a shortlist of the top-10 protected areas that should be prioritized for immediate jaguar conservation efforts and 74 for short-term action. Many of these are located at the deforestation frontier or in important boundaries with neighboring countries (e.g., Peruvian, Colombian and Venezuelan Amazon). The predicament of a safe future for jaguars can only be ensured if protected areas persist and resist downgrading and downsizing due to both external anthropogenic threats and geopolitical pressures (e.g., infrastructure development and frail law enforcement).


Asunto(s)
Conservación de los Recursos Naturales , Panthera , Animales , Conservación de los Recursos Naturales/métodos , Brasil , Ecosistema , Densidad de Población
16.
Curr Biol ; 33(2): 389-396.e3, 2023 01 23.
Artículo en Inglés | MEDLINE | ID: mdl-36580916

RESUMEN

The conversion of natural ecosystems into human-modified landscapes (HMLs) is the main driver of biodiversity loss in terrestrial ecosystems.1,2,3 Even when species persist within habitat remnants, populations may become so small that ecological interactions are functionally lost, disrupting local interaction networks.4,5 To uncover the consequences of land use changes toward ecosystem functioning, we need to understand how changes in species richness and abundance in HMLs6,7,8 rearrange ecological networks. We used data from forest vertebrate surveys and combined modeling and network analysis to investigate how the structure of predator-prey networks was affected by habitat insularization induced by a hydroelectric reservoir in the Brazilian Amazonia.9 We found that network complexity, measured by interaction diversity, decayed non-linearly with decreasingly smaller forest area. Although on large forest islands (>100 ha) prey species were linked to 3-4 potential predators, they were linked to one or had no remaining predator on small islands. Using extinction simulations, we show that the variation in network structure cannot be explained by abundance-related extinction risk or prey availability. Our findings show that habitat loss may result in an abrupt disruption of terrestrial predator-prey networks, generating low-complexity ecosystems that may not retain functionality. Release from predation on some small islands may produce cascading effects over plants that accelerate forest degradation, whereas predator spillover on others may result in overexploited prey populations. Our analyses highlight that in addition to maintaining diversity, protecting large continuous forests is required for the persistence of interaction networks and related ecosystem functions.


Asunto(s)
Ecosistema , Cadena Alimentaria , Animales , Humanos , Bosques , Biodiversidad , Vertebrados
17.
Trends Ecol Evol ; 38(2): 113-116, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36528414

RESUMEN

Wholesale conversion of natural Amazonian ecosystems has been encouraged by Brazil's extreme antienvironmental government, and historical forest loss explains municipal-scale voting prevalence. Embracing a new administration would strengthen local-to-regional governance, suppress illegal land grabbing, deforestation, logging, and gold mining, thereby protecting the world's most species-rich forest domain and ensuring global sustainability.


Asunto(s)
Ecosistema , Política Ambiental , Brasil , Conservación de los Recursos Naturales , Bosques
18.
Biota Neotrop. (Online, Ed. ingl.) ; 23(4): e20231551, 2023. tab, graf
Artículo en Inglés | LILACS-Express | LILACS | ID: biblio-1527946

RESUMEN

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.

19.
Am J Primatol ; 84(12): e23446, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-36268580

RESUMEN

Although the species-area relationship is well known, it may interact with and be augmented or cancelled out by other factors, such as local human disturbance. We used data on site occupancy of the Endangered blonde capuchin monkey (Sapajus flavius) based primarily on a standardized program of local interviews to model the influence of past human disturbance on the occurrence of this species across remaining forest patches of northeastern Brazil within the Atlantic Forest and Caatinga biomes. To do so, we assessed environmental covariates that best represent the history of human impacts. We then used single-species occupancy models to assess site occupancy, while controlling for detection error during sampling. Surprisingly, we obtained a higher occupancy rate in the more arid Caatinga remnants than in the more mesic Atlantic Forest. Habitat patch size, history of site protection, and annual precipitation were the best predictors of local occupancy. Historical human disturbance, including subsistence hunting, has exerted considerable impact on the modern distribution of the blonde capuchin, whose geographic range largely spans a region historically lacking any wildlife protection. Matrix vegetation structure across the Caatinga, which so far has averted large-scale mechanized agriculture, also creates a benign landscape that likely benefits contemporary capuchin occupancy. Local extinctions of this endangered primate will most likely continue unabated unless a ban on hunting in remaining Atlantic Forest and Caatinga fragments can be enforced.


Asunto(s)
Ecosistema , Bosques , Humanos , Animales , Cebus , Brasil
20.
Sci Adv ; 8(34): eabm0397, 2022 Aug 26.
Artículo en Inglés | MEDLINE | ID: mdl-36026453

RESUMEN

Deforestation and fragmentation are pervasive drivers of biodiversity loss, but how they scale up to entire landscapes remains poorly understood. Here, we apply species-habitat networks based on species co-occurrences to test the effects of insular fragmentation on multiple taxa-medium-large mammals, small nonvolant mammals, lizards, understory birds, frogs, dung beetles, orchid bees, and trees-across 22 forest islands and three continuous forest sites within a river-damming quasi-experimental landscape in Central Amazonia. Widespread, nonrandom local species extinctions were translated into highly nested networks of low connectance and modularity. Networks' robustness considering the sequential removal of large-to-small sites was generally low; between 5% (dung beetles) and 50% (orchid bees) of species persisted when retaining only <10 ha of islands. In turn, larger sites and body size were the main attributes structuring the networks. Our results raise the prospects that insular forest fragmentation results in simplified species-habitat networks, with distinct taxa persistence to habitat loss.

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