Understanding Of Changes In Biodiversity Research Articles

Incorporating Phenology to Estimate Species’ Population Trends from Snapshot Citizen-Science Data

AbstractCitizen-science data are increasingly used to contribute to our understanding of biodiversity change, but analysing such data requires suitable statistical methods, often to deal with forms of bias. We develop a new approach for modelling data from a snapshot, mass-participation citizen-science scheme for UK butterflies, the Big Butterfly Count (BBC). Butterfly abundance varies throughout the year as one or more generations of each species emerge and die off, and the timing (phenology) of emergences varies annually due to weather and climate. Thus, counts from the short 3-week BBC sampling period are susceptible to bias due to this inter-annual variation in phenology. We adapt the Generalised Abundance Index, drawing upon phenology estimates from standardised monitoring scheme data, to account for phenological bias in the estimation of species’ abundance trends from BBC data. The method is demonstrated via application to empirical and simulated data, revealing that not accounting for phenology leads to biased trend estimates, particularly for summer-flying single-generation species. Drawing upon phenology information, the new approach allows for the reporting of abundance trends from a snapshot citizen-science scheme, creating the potential to maximise available data sources to increase our understanding of changes in butterfly populations, particularly in urban environments.

Tracking climate-change-induced biological invasions by metabarcoding archived natural eDNA samplers

In a time of unprecedented environmental change, understanding the response of organisms and ecosystems to change is paramount1. However, our knowledge of anthropogenic impacts on ecosystems is limited by a lack of standardized retrospective biomonitoring data2. Here, we use a four-decade time series of archived blue mussels to trace spatiotemporal biodiversity change in coastal ecosystems. The filter-feeding mussels, which were initially collected for pollution monitoring, can serve as natural eDNA samplers, carrying an imprint of the surrounding aquatic community at the time of sampling3. By sequencing the preserved DNA, we characterize highly diverse mussel-associated communities and reconstruct the invasion trajectory of an invasive species, the barnacle Austrominius modestus. We quantitatively trace population growth of the invader to the detriment of native taxa and uncover repeated population collapses and reinvasions after cold winters. By providing highly resolved temporal data on community assembly and global warming-driven invasion processes, natural eDNA sampler time series overcome a critical shortfall in our understanding of biodiversity change in the Anthropocene.

Achieving global biodiversity goals by 2050 requires urgent and integrated actions

Achieving global biodiversity goals by 2050 requires urgent and integrated actions

Niche breadth and biodiversity change derived from marine Amphipoda species off Iceland.

Understanding the ecological requirements and thresholds of individual species is crucial to better predict potential outcomes of climate change on species distribution. In particular, species optima and lower and upper limits along resource gradients require attention. Based on Huisman‐Olff‐Fresco (HOF) models, we determined species‐specific responses along gradients of nine environmental parameters including depth in order to estimate niche attributes of 30 deep‐sea benthic amphipods occurring around Iceland. We, furthermore, examined the relationships between niche breadth, occupancy, and geographic range assuming that species with a wider niche are spatially more widely dispersed and vice versa. Overall, our results reveal that species react very differently to environmental gradients, which is independent of the family affiliation of the respective species. We could infer a strong relationship between occupancy and geographic range and also relate this to differences in niche breadth; that is specialist species with a narrow niche had a more limited distribution and may thus be more threatened by changing environmental conditions than generalist species, which are more widespread. Given the preponderance of rare species in the deep sea, this implies that many species could be at risk. However, this must be carefully weighed against geographical data gaps in this area, given that many deep‐sea areas are severely undersampled and the true distribution of most species is unknown. After all, our results underline that an accurate taxonomic classification is of crucial importance, without which ecological niche properties cannot be determined and which is hence fundamental for the assessment and understanding of changes in biodiversity in the face of increasing human perturbations.

Temporal lags in observed and dark diversity in the Anthropocene.

Understanding biodiversity changes in the Anthropocene (e.g. due to climate and land-use change) is an urgent ecological issue. This important task is challenging because global change effects and species responses are dependent on the spatial scales considered. Furthermore, responses are often not immediate. However, both scale and time delay issues can be tackled when, at each study site, we consider dynamics in both observed and dark diversity. Dark diversity includes those species in the region that can potentially establish and thrive in the local sites' conditions but are currently locally absent. Effectively, dark diversity connects biodiversity at the study site to the regional scales and defines the site-specific species pool (observed and dark diversity together). With dark diversity, it is possible to decompose species gains and losses into two space-related components: one associated with local dynamics (species moving from observed to dark diversity and vice versa) and another related to gains and losses of site-specific species pool (species moving to and from the pool after regional immigration, regional extinction or change in local ecological conditions). Extinction debt and immigration credit are useful to understand dynamics in observed diversity, but delays might happen in species pool changes as well. In this opinion piece we suggest that considering both observed and dark diversity and their temporal dynamics provides a deeper understanding of biodiversity changes. Considering both observed and dark diversity creates opportunities to improve conservation by allowing to identify species that are likely to go regionally extinct as well as foreseeing which of the species that newly arrive to the region are more likely to colonize local sites. Finally, by considering temporal lags and species gains and losses in observed and dark diversity, we combine phenomena at both spatial and temporal scales, providing a novel tool to examine biodiversity change in the Anthropocene.

Marine Vertebrate Biodiversity and Distribution Within the Central California Current Using Environmental DNA (eDNA) Metabarcoding and Ecosystem Surveys

Environmental DNA (eDNA) metabarcoding is a new approach for assessing marine biodiversity that may overcome challenges of traditional monitoring and complement both existing surveys and biodiversity assessments. There are limited eDNA studies that evaluate vertebrate biodiversity in the marine environment or compare patterns of biodiversity with traditional methods. This study uses eDNA metabarcoding of the mitochondrial 12S rRNA genes present in seawater samples to characterize vertebrate biodiversity and distribution within National Marine Sanctuaries located in the California Current upwelling ecosystem. The epipelagic community in the study region has been monitored using traditional (mid-water trawl and marine mammal) survey methods since 1983. During 2016 and 2017, we concurrently sampled the epipelagic community using traditional survey methods and water for eDNA analysis to assess agreement among the methods. We collected replicate eDNA samples from 25 stations at depths of 10, 40, and 80 m, resulting in 131 small volume (1 L) environmental water samples to examine eDNA sequences. Across the eDNA and traditional survey methods, 80 taxa were identified. Taxa identified by eDNA partially overlapped with taxa through trawl and marine mammal surveys, but more taxa were identified by eDNA. Diversity and distribution patterns of marine vertebrates inferred from eDNA sequences reflected known spatial distribution patterns in species occurrence and community structure (e.g., cross-shelf and alongshore patterns). During both years we identified fishery taxa Sebastes (rockfish), Merluccius (hake), Citharichthys (sanddab), and Engraulis (anchovy) across the majority of the stations using eDNA metabarcoding. The marine vertebrate assemblage identified by eDNA in 2016 was statistically different from the 2017 assemblage and more marine mammals were identified in 2017 than in 2016. Differences in assemblages identified by eDNA were coincident with different oceanographic conditions (e.g., upwelling and stratification). In 2016 weak upwelling and warmer than average conditions were measured, and vertebrate assemblages were not different among ecological regions (Point Reyes, Pescadero, and Monterey Bay). While in 2017, average upwelling conditions returned, vertebrate assemblages differed at each region. This study illustrates that eDNA provides a new baseline for vertebrate assessments that can both augment traditional biomonitoring surveys and aid our understanding of changes in biodiversity.

Spatial structure of species change

Biodiversity Biodiversity is undergoing rapid change driven by climate change and other human influences. Blowes et al. analyze the global patterns in temporal change in biodiversity using a large quantity of time-series data from different regions (see the Perspective by Eriksson and Hillebrand). Their findings reveal clear spatial patterns in richness and composition change, where marine taxa exhibit the highest rates of change. The marine tropics, in particular, emerge as hotspots of species richness losses. Given that human activities are affecting biodiversity in magnitudes and directions that differ across the planet, these findings will provide a much needed biogeographic understanding of biodiversity change that can help inform conservation prioritization. Science , this issue p. [339][1]; see also p. [308][2] [1]: /lookup/doi/10.1126/science.aaw1620 [2]: /lookup/doi/10.1126/science.aaz4520

Large-scale changes in the littoral fish communities of lakes in southeastern Ontario, Canada

Biodiversity loss is a serious issue for freshwater fishes in temperate climates and there is a need for more information in this area. A study was conducted to assess fish community changes in the littoral zone of 22 lakes over a 45 year period (compared years 1969–1979 and year 2014). To compare fish communities, historical seining records were compiled for 22 inland lakes and compared with contemporary data sampled using the same protocol. Fish abundance data analyzed using a multivariate approach identified a shift from cyprinid-dominated communities to centrarchid-dominated communities between time periods. There was no evidence to support a strong influence of invasive species on these communities, but there have been significant changes in temperature and land use around these lakes since the historical data sets were collected. This is an important contribution to our understanding of biodiversity change in North American freshwater fish communities and may influence fisheries management approaches in the future.

Successful conservation of global waterbird populations depends on effective governance.

Understanding global patterns of biodiversity change is crucial for conservation research, policies and practices. However, for most ecosystems, the lack of systematically collected data at a global level limits our understanding of biodiversity changes and their local-scale drivers. Here we address this challenge by focusing on wetlands, which are among the most biodiverse and productive of any environments and which provide essential ecosystem services, but are also amongst the most seriously threatened ecosystems. Using birds as an indicator taxon of wetland biodiversity, we model time-series abundance data for 461 waterbird species at 25,769 survey sites across the globe. We show that the strongest predictor of changes in waterbird abundance, and of conservation efforts having beneficial effects, is the effective governance of a country. In areas in which governance is on average less effective, such as western and central Asia, sub-Saharan Africa and South America, waterbird declines are particularly pronounced; a higher protected area coverage of wetland environments facilitates waterbird increases, but only in countries with more effective governance. Our findings highlight that sociopolitical instability can lead to biodiversity loss and undermine the benefit of existing conservation efforts, such as the expansion of protected area coverage. Furthermore, data deficiencies in areas with less effective governance could lead to underestimations of the extent of the current biodiversity crisis.

Is a picture worth a thousand species? Evaluating human perception of biodiversity intactness using images of cumulative effects

Public demand to conserve biodiversity has resulted in increased monitoring efforts for a vast number of species. Faced with reporting on the large amounts of information generated by biodiversity monitoring, there is a desire to have state variables that simplify this complexity. Intactness indices describe the deviation of the state of biodiversity from a specified reference condition. An effective intactness index should not only statistically describe changes in biodiversity when change occurs but also resonate with people in a way that they have a clear picture of the type of change that has occurred. We used an online survey to evaluate whether public perception of cumulative impacts as viewed through images of disturbed boreal landscapes was correlated with actual indices of avian biodiversity intactness. We found people accurately ranked landscapes with the most human disturbance relative to an undisturbed reference state. The variable the best predicted perceived intactness was the proportion of mature forest cover remaining. Dissection by roads and fragmentation effects by forestry, agriculture, and urbanization explained less but a significant amount of variation. Biocentric individuals and non-hunters viewed landscapes as generally being less intact. Absolute intactness scores from field data deviated from perceived intactness. Landscapes with little human disturbance (i.e. a single road) were perceived to have lower intactness than what was actually observed in bird communities and landscapes with no forest were perceived as being more impacted than they were. Intactness indices can enhance understanding of biodiversity change but caution must be exercised to ensure a clear understanding of what the absolute value of indices represent.

Modelling for species and habitats: new opportunities for problem solving

The biodiversity convention aims at conserving biodiversity and guaranteeing fair and sustainable human use of biodiversity. The convention further requires that the causes of biodiversity decline are identified and evaluated, and that effective conservation and monitoring strategies are developed. Resolving these needs requires a different approach than those described in the last Global Biodiversity Assessment. This assessment tended to be descriptive and did not comprehensively attempt to describe future trends in biodiversity in relation to the major threats: habitat destruction, overexploitation, alien species, pollution and climate change. Integrated assessment modelling and scenario development have therefore not been introduced and applied to assess changes in biodiversity. These tools were originally developed for acidification and climate-change impact assessments but are also well suited to analysing other environmental problems. The implemented business-as-usual scenarios show the causes of biodiversity decline to differ regionally. Although complex patterns of causal factors and changes occur in many regions, a valid (but generalised) statement is that climate change causes biodiversity decline in industrialised regions, while in developing regions expanding land use is the major contributor. The scenarios further highlight that despite population growth contributing to the problem, rapidly increasing consumption patterns, rapid expansion of rangelands to support changing diets and too slow-moving technological innovations are major attributes of land-use change and biodiversity decline. Finally, it is concluded that scenario studies transparently highlight the complex systemic interactions and feedback between society and the other components of the earth’s system. In addition, scenarios can contribute well to improving the understanding of changes in biodiversity at global and regional levels of assessment.