As biodiversity decreases worldwide, the development of effective techniques to track changes in ecological communities becomes an urgent challenge. Together with other emerging methods in ecology, acoustic indices are increasingly being used as novel tools for rapid biodiversity assessment. These indices are based on mathematical formulae that summarise the acoustic features of audio samples, with the aim of extracting meaningful ecological information from soundscapes. However, the application of this automated method has revealed conflicting results across the literature, with conceptual and empirical controversies regarding its primary assumption: a correlation between acoustic and biological diversity. After more than a decade of research, we still lack a statistically informed synthesis of the power of acoustic indices that elucidates whether they effectively function as proxies for biological diversity. Here, we reviewed studies testing the relationship between diversity metrics (species abundance, species richness, species diversity, abundance of sounds, and diversity of sounds) and the 11 most commonly used acoustic indices. From 34 studies, we extracted 364 effect sizes that quantified the magnitude of the direct link between acoustic and biological estimates and conducted a meta-analysis. Overall, acoustic indices had a moderate positive relationship with the diversity metrics (r = 0.33, CI [0.23, 0.43]), and showed an inconsistent performance, with highly variable effect sizes both within and among studies. Over time, studies have been increasingly disregarding the validation of the acoustic estimates and those examining this link have been progressively reporting smaller effect sizes. Some of the studied indices [acoustic entropy index (H), normalised difference soundscape index (NDSI), and acoustic complexity index (ACI)] performed better in retrieving biological information, with abundance of sounds (number of sounds from identified or unidentified species) being the best estimated diversity facet of local communities. We found no effect of the type of monitored environment (terrestrial versus aquatic) and the procedure for extracting biological information (acoustic versus non-acoustic) on the performance of acoustic indices, suggesting certain potential to generalise their application across research contexts. We also identified common statistical issues and knowledge gaps that remain to be addressed in future research, such as a high rate of pseudoreplication and multiple unexplored combinations of metrics, taxa, and regions. Our findings confirm the limitations of acoustic indices to efficiently quantify alpha biodiversity and highlight that caution is necessary when using them as surrogates of diversity metrics, especially if employed as single predictors. Although these tools are able partially to capture changes in diversity metrics, endorsing to some extent the rationale behind acoustic indices and suggesting them as promising bases for future developments, they are far from being direct pr...
Aim: Invasive alien species are a growing problem worldwide due to their ecological, economic and human health impacts. The "killer shrimp" Dikerogammarus villosus is a notorious invasive alien amphipod from the Ponto-Caspian region that has invaded many fresh and brackish waters across Europe. Understandings of large-scale population dynamics of highly impactful invaders such as D. villosus are lacking, inhibiting predictions of impact and efficient timing of management strategies. Hence, our aim was to assess trends and dynamics of D. villosus as well as its impacts in freshwater rivers and streams.Location: Europe. Methods:We analysed 96 European time series between 1994 and 2019 and identified trends in the relative abundance (i.e. dominance %) of D. villosus in invaded time series, as well as a set of site-specific characteristics to identify drivers and determinants of population changes and invasion dynamics using meta-regression modelling.We also looked at the spread over space and time to estimate the invasion speed (km/year) of D. villosus in Europe. We investigated the impact of D. villosus abundance on recipient community metrics (i.e. abundance, taxa richness, temporal turnover, Shannon diversity and Pielou evenness) using generalized linear models.Results: Population trends varied across the time series. Nevertheless, community dominance of D. villosus increased over time across all time series. The frequency of occurrences (used as a proxy for invader spread) was well described by a Pareto distribution, whereby we estimated a lag phase (i.e. the time between introduction and spatial expansion) of approximately 28 years, followed by a gradual increase before new occurrences declined rapidly in the long term. D. villosus population change was associated with decreased taxa richness, community turnover and Shannon diversity. Main Conclusion:Our results show that D. villosus is well-established in European waters and its abundance significantly alters ecological communities. However, the multidecadal lag phase prior to observed spatial expansion suggests that initial introductions by D. villosus are cryptic, thus signalling the need for more effective early detection methods.
Motivation We accessed published and unpublished floristic sources to compile a comprehensive species list of the Iberian–Balearic terrestrial vascular flora and generate AFLIBER, an accurate floristic database of georeferenced plant occurrence records. Main type of variable contained Species distribution data totalling 1,824,549 plant occurrence records corresponding to 6,456 species and subspecies. Spatial location and grain The western Mediterranean, including inland territories of Spain, Portugal and Andorra and the adjacent archipelagos of Berlengas, Columbretes and the Balearic Islands, covered by 6,316 UTM quadrangular grid cells of 10 km resolution. Time period All distributional trustable records were considered to create the AFLIBER database, most of them dating from the 1960s onwards. Major taxa and level of measurement Terrestrial vascular plant species and subspecies. Software format Data are supplied as comma‐separated text (csv) files.
Pretende-se com este trabalho evidenciar a necessidade de enquadrar o ensino da Engenharia Hidráulica e dos Recursos Hídricos, e outros ramos da engenharia, num contexto em que se integram os conhecimentos no âmbito dos fundamentos de engenharia e os fundamentos das ciências sociais e ambientais; e patentear as vantagens deste enquadramento. Entramos numa fase em que, felizmente, já é consensual admitir-se que os aspectos sócio-ambientais não podem ser descurados a favor dos benefícios económicos imediatos. Hoje o ambiente tem um estatuto jurídico (i.e., é atribuído um direito legal às florestas, aos oceanos, aos rios e a todos esses objectos que chamamos naturais no ambiente). Porém, a concretização destes desideratos requer uma mudança/actualização e adequação das Engenharias que mais intervêm no espaço físico ou biofísico (Engenharia Civil, Agronómica, Geológica, entre outras) ao contexto dos valores actuais incluindo nos planos de estudos das engenharias matérias que permitam ao engenheiro ter uma visão integrada do impacte (sócio-cultural, económico, e ambiental) das suas intervenções no sistema natural.
AimThe increasing availability of molecular information has lifted our understanding of species evolutionary relationships to unprecedent levels. However, current estimates of the world's biodiversity suggest that about a fifth of all extant species are yet to be described, and we still lack molecular information for many of the known species. Hence, evolutionary biologists will have to tackle phylogenetic uncertainty for a long time to come. This prospect has urged the development of software to expand phylogenies based on non‐molecular phylogenetic information, and while the available tools provide some valuable features, major drawbacks persist and some of the proposed solutions are hardly generalizable to any group of organisms.InnovationHere, we present a completely generalized and flexible framework to expand incomplete phylogenies. The framework is implemented in the R package “randtip”, a toolkit of functions that was designed to randomly bind phylogenetically uncertain taxa in backbone phylogenies through a fully customizable and automatic procedure that uses taxonomic ranks as a major source of phylogenetic information. Although randtip can generate fully operative phylogenies for any group of organisms using just a list of species and a backbone tree, we stress that the “blind” expansion of phylogenies using “quick‐and‐dirty” approaches often leads to suboptimal solutions. Thus, we discuss a variety of circumstances that may require customizing simulation parameters beyond default settings to optimally expand the trees, including a detailed step‐by‐step tutorial that was designed to provide guidelines to non‐specialist users.Main ConclusionsPhylogenetic uncertainty should be tackled with caution, assessing potential pitfalls and opportunities to optimize parameter space prior to launch any simulation. Used judiciously, our framework will help evolutionary biologists to efficiently expand incomplete phylogenies and thereby account for phylogenetic uncertainty in quantitative analyses.
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