The list of threatened species (Red List), established by the International Union for Conservation of Nature (IUCN), aims to provide global assessments on the extinction risk of species. However, ...protecting vulnerable populations requires establishing threat criteria at sub-global scales, e.g., national Red Lists. In data-poor contexts, typical of many developing countries, assessing threat status by applying IUCN criteria constitutes a major challenge, which may be one reason for mismatches between national and global Red List assessments. Despite the intense harvesting of threatened elasmobranchs species in Brazilian waters, Brazilian fisheries monitoring has ceased to exist for nearly a decade. This jeopardizes accurate assessment of species’ conservation status at a local scale. In the absence of fisheries records, local ecological knowledge (LEK) provides an alternative option to obtain reliable information on targeted species. We interviewed 186 fishers from four Brazilian Northeastern states, whose recollections spanned six decades and documented catches or sightings of 19 shark species. For eight species with sufficient data, temporal trends in maximum length of sharks caught by fishers of different age-classes were statistically tested. Four species’ maximum length declined over time, while four were primarily captured by elderly fishers, with few or no recent catches reported. Of these species, one is classified more conservatively in the national Red List vs. IUCN Red List, which is supported by LEK results. Contrastingly, two species are classified less conservatively at the national level than by IUCN, such that upgrading and matching IUCN’s conservation criteria is warranted. We suggest that LEK provides support for conservation status listing in data-poor contexts.
The ecological consequences of biological range extensions reflect the interplay between the functional characteristics of the newly arrived species and their recipient ecosystems. Teasing apart the ...relative contribution of each component is difficult because most colonization events are studied retrospectively, i.e., after a species became established and its consequences apparent. We conducted a prospective experiment to study the ecosystem consequences of a consumer introduction, using whole-stream metabolism as our integrator of ecosystem activity. In four Trinidadian streams, we extended the range of a native fish, the guppy (
Poecilia reticulata
), by introducing it over barrier waterfalls that historically excluded it from these upper reaches. To assess the context dependence of these range extensions, we thinned the riparian forest canopy on two of these streams to increase benthic algal biomass and productivity. Guppy’s range extension into upper stream reaches significantly impacted stream metabolism but the effects depended upon the specific stream into which they had been introduced. Generally, increases in guppy biomass caused an increase in gross primary production (GPP) and community respiration (CR). The effects guppies had on GPP were similar to those induced by increased light level and were larger in strength than the effects stream stage had on CR. These results, combined with results from prior experiments, contribute to our growing understanding of how consumers impact stream ecosystem function when they expand their range into novel habitats. Further study will reveal whether local adaptation, known to occur rapidly in these guppy populations, modifies the ecological consequences of this species introduction.
Brazil unwisely gives pesticides a free pass Coelho, Felipe E A; Lopes, Lara C; Cavalcante, Raquel M S ...
Science (American Association for the Advancement of Science),
08/2019, Letnik:
365, Številka:
6453
Journal Article
For many aquatic organisms, olfactory-mediated behaviour is essential to the maintenance of numerous fitness-enhancing activities, including foraging, reproduction and predator avoidance. Studies in ...both freshwater and marine ecosystems have demonstrated significant impacts of anthropogenic acidification on olfactory abilities of fish and macroinvertebrates, leading to impaired behavioural responses, with potentially far-reaching consequences to population dynamics and community structure. Whereas the ecological impacts of impaired olfactory-mediated behaviour may be similar between freshwater and marine ecosystems, the underlying mechanisms are quite distinct. In acidified freshwater, molecular change to chemical cues along with reduced olfaction sensitivity appear to be the primary causes of olfactory-mediated behavioural impairment. By contrast, experiments simulating future ocean acidification suggest that interference of high CO2 with brain neurotransmitter function is the primary cause for olfactory-mediated behavioural impairment in fish. Different physico-chemical characteristics between marine and freshwater systems are probably responsible for these distinct mechanisms of impairment, which, under globally rising CO2 levels, may lead to strikingly different consequences to olfaction. While fluctuations in pH may occur in both freshwater and marine ecosystems, marine habitat will remain alkaline despite future ocean acidification caused by globally rising CO2 levels. In this synthesis, we argue that ecosystem-specific mechanisms affecting olfaction need to be considered for effective management and conservation practices.
In the developing world, the exploitation of threatened species jeopardizes their permanence in the wild. Because not all captures are intentional, for instance when capture methods have low ...selectivity, pressure on these species may be lessened by releasing living incidentally caught animals. However, it is often unrealistic to expect people to voluntarily do so because it means foregoing the benefits of resource extraction. Financial incentives for such animal release may foster conservation objectives. Reducing human–animal conflicts, protecting natural habitat, and conserving nests of threatened species are examples of conservation benefits that can be built on financial reward systems. However, incentives aiming to protect unintentionally captured threatened species are scarce. We considered pay for release, a type of ecosystem‐service payment designed to foster the release of incidentally captured threatened species. We aimed to determine the best conditions to implement this scheme, its potential benefits (e.g., incentivizing the release of threatened species), and pitfalls and priority research needs (e.g., required conditions for pay for release to work) to show that its global applicability is possible. Given that approaches solely based on education and law enforcement may be ineffective under some circumstances, we argue that pay for release can protect incidentally captured endangered species if used under conditions conducive for its success. When local participants’ intrinsic motivation for conservation is weak, but the release of incidentally live‐caught animals into their habitats is readily achievable, pay‐for‐release schemes could jump start urgently needed conservation efforts against indiscriminate animal harvesting.
Article impact statement: Financial incentives offered to promote the release of incidentally captured animals to reduce by‐catch mortality of threatened species.
Evaluación de los Incentivos de Pago por Liberación para las Especies Amenazadas Capturadas Involuntariamente
Resumen
En este mundo en desarrollo, la explotación de las especies amenazadas pone en peligro su permanencia en la naturaleza. Ya que no todas las capturas son voluntarias, por ejemplo cuando los métodos de captura tienen una selectividad baja, la presión que se ejerce sobre estas especies puede aminorarse con la liberación de animales capturados vivos accidentalmente. Sin embargo, a menudo es poco realista esperar que las personas hagan esto voluntariamente, pues representa una renuncia a los beneficios de la extracción de recursos. Los incentivos financieros para dichas liberaciones de animales pueden promover los objetivos de conservación. La reducción de los conflictos humano‐animal, la protección del hábitat natural y la conservación de los nidos de las especies amenazadas son ejemplos de los beneficios de conservación que pueden construirse con los sistemas de recompensas financieras. Sin embargo, los incentivos que buscan proteger a las especies amenazadas que son capturadas involuntariamente son escasos. Consideramos el pago por liberación, un tipo de pago por servicio ambiental diseñado para fomentar la liberación de las especies amenazadas capturadas accidentalmente. Buscamos determinar las mejores condiciones para implementar este programa, sus beneficios potenciales (p. ej.: la incentivación de la liberación de especies amenazadas) y los inconvenientes y las necesidades de la prioridad de investigación (p. ej.: las condiciones requeridas para que funcione el pago por liberación) para mostrar que su aplicación global es posible. Ya que las estrategias basadas solamente en la educación y la aplicación de la ley pueden no ser efectivas bajo ciertas circunstancias, argumentamos que el pago por la liberación puede proteger a las especies amenazadas capturadas accidentalmente si se usa bajo condiciones propicias para su éxito. Cuando los participantes locales tienen una motivación intrínseca débil pero la liberación de animales capturados vivos accidentalmente a sus hábitats es inmediatamente alcanzable, los programas de pago por liberación podrían arrancar los esfuerzos de conservación tan necesarios para combatir la extracción indiscriminada de animales.
摘要
在发展中国家, 对受胁迫物种的利用已危及其野外生存。由于对动物的捕获有时并非有意, 比如存在捕获方法选择性较低的情况, 因而放生这些偶然捕获的活体动物可以减轻其物种续存的压力。然而, 期望人们自愿这样做是不现实的, 因为这意味着放弃了资源利用的好处。通过金钱奖励动物放生行为可能会促进保护目标的实现。类似这样建立在金钱奖励系统上的保护效益的例子包括减少人与动物之间的冲突, 保护自然生境, 保护受胁迫物种的巢穴等。然而, 以保护偶然捕获的受胁迫物种为目标的激励措施还很少。我们研究了付费放生, 这是一种对生态系统服务的付费, 旨在促进对偶然捕获的受胁迫物种的释放。我们的目标是确定实施该计划的最佳条件、潜在利益 (如激励放生受胁迫物种) 、其中的误区及优先研究需求 (如实现付费放生的必要条件), 以说明其在全世界范围内的适用性。考虑到仅仅建立在教育和执法上的方法在某些情况下存在局限性, 我们认为, 在有利的条件下实施付费放生计划, 可以保护偶然捕获的濒危物种。如果当地参与者的内在的保护动机很弱, 但将偶然捕获的活体动物放生到它们的栖息地却十分简单, 那么付费放生计划可能会快速推动急需的保护工作来防止不加区分地捕捞动物。 【翻译: 胡怡思; 审校: 聂永刚】
Plastic debris collar wrappings (PDCW) are involved in the frequent entanglement of several groups of marine animals. In fishes, however aside from ‘ghost fishing’, PDCW events are rarely documented, ...and no record of this occurrence exists in tropical reef fishes. Here, we present records for four species afflicted by plastic debris collars. Observations occurred during snorkeling, and included the silver mojarra Eucinostomus argenteus, Atlantic thread herring Ophistonema oglinum, tomtate grunt Haemulon aurolineatum and gray parrotfish Sparisoma axillare. While PDCW may not create an instantaneous source of mortality, our observations suggest that debilitating stress, created by reduced swimming performances, feeding and/or antipredator behavior are likely consequences for afflicted individuals. Given the importance of these performances on survival, reduction in fitness is expected. This note aims to report cases of PDCW and underscore that such interactions between fishes and plastic pollution may be more prevalent than previously expected in coastal reef habitats.
•Plastic debris collar wrappings (PDCW) are involved in the frequent entanglement of several groups of marine animals.•We present records for four species afflicted by plastic debris collars.•PDCW reduced fish swimming performances, feeding and antipredator behavior.•Given the importance of these performances on survival, reduction in fitness is expected.
Decades of ecological study have demonstrated the importance of top-down and bottom-up controls on food webs, yet few studies within this context have quantified the magnitude of energy and material ...fluxes at the whole-ecosystem scale. We examined top-down and bottom-up effects on food web fluxes using a field experiment that manipulated the presence of a consumer, the Trinidadian guppy Poecilia reticulata, and the production of basal resources by thinning the riparian forest canopy to increase incident light. To gauge the effects of these reach-scale manipulations on food web fluxes, we used a nitrogen (¹⁵N) stable isotope tracer to compare basal resource treatments (thinned canopy vs. control) and consumer treatments (guppy introduction vs. control). The thinned canopy stream had higher primary production than the natural canopy control, leading to increased N fluxes to invertebrates that feed on benthic biofilms (grazers), fine benthic organic matter (collector-gatherers), and organic particles suspended in the water column (filter feeders). Stream reaches with guppies also had higher primary productivity and higher N fluxes to grazers and filter feeders. In contrast, N fluxes to collector-gatherers were reduced in guppy introduction reaches relative to upstream controls. N fluxes to leaf-shredding invertebrates, predatory invertebrates, and the other fish species present (Hart's killifish, Anablepsoides hartii) did not differ across light or guppy treatments, suggesting that effects on detritus-based linkages and upper trophic levels were not as strong. Effect sizes of guppy and canopy treatments on N flux rates were similar for most taxa, though guppy effects were the strongest for filter feeding invertebrates while canopy effects were the strongest for collector-gatherer invertebrates. Combined, these results extend previous knowledge about top-down and bottom-up controls on ecosystems by providing experimental, reach-scale evidence that both pathways can act simultaneously and have equally strong influence on nutrient fluxes from inorganic pools through primary consumers.
Escape behaviors have a great potential as an indicator of the efficacy of management. For instance, the degree of fear perceived by fishes targeted by fisheries is frequently higher in unprotected ...marine areas than in areas where some protection is provided. We systematically reviewed the literature on how fear, which we define as variation in escape behavior, was quantified in reef fishes. In the past 25 years, a total of 33 studies were identified, many of which were published within the last five years and nearly 40% of those (n = 13) focused on Indo-Pacific reefs, showing that there are still many geographical gaps. While eleven escape metrics were identified to evaluate fish escape, flight initiation distance (FID) was the most commonly employed (n = 23). FID was used to study different questions of applied and theoretical ecology, which involved 14 reef fish families. We also used a formal meta-analysis to investigate the effects of fishing by comparing FID inside and outside marine protected areas. Fishes outside MPAs had increased FID compared to those inside MPAs. The Labridae family had a significantly higher effect sizes than Acanthuridae and Epinephelidae, suggesting that fishes in this family may be indicators of effective MPAs using FID. We conclude that protocols aimed to quantify fear in fishes, which provide accurate assessments of fishing effects on fish escape behavior, will help gauge the compliance of marine protected areas.
•Escape behaviors have a great potential as an indicator of the efficacy of management.•We systematically reviewed the literature on how fear, defined as variation in escape behavior, was quantified in reef fishes.•Flight initiation distance (FID) was the most commonly employed.•Fishes outside MPAs had increased FID compared to those inside MPAs.•The Labridae family had a significantly higher effect sizes.
Many fish species have behavioral traits related to reproduction that aim to improve egg conditions and survival of early life stages. Here, we provide the first detailed description of reproductive ...strategies performed by the rhomboid mojarra, Diapterus rhombeus. We based this description on several mating events, which occurred in mangroves located in Todos os Santos Bay, Brazil. These spawning events occurred at the mangrove fringe in the month of August in 2013 and 2014, which suggests that these spawning events occur predictably in space and time. Two principal behavioral tactics were observed and involved breeding aggregation and a unique nest-clearing behavior. Following these behaviors, many fish exhibited an extreme lethargic state during which they took refuge amidst mangrove roots. Overall, these observations revealed an unexpected and uncommon set of behaviors in an otherwise well-studied species. The present study not only highlights basic gaps in our understanding of estuarine species but also suggests that future investigations are poised to yield exciting and insightful findings.
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