Biology subjects

Haugaasen, T.

Publications and source records attributed to Haugaasen, T..

5 recordsLinked to original sources

bioRxiv2023

Extending species-area relationships into the realm of ecoacoustics: The soundscape-area relationship

The rise in species richness with area is one of the best-studied patterns in ecology. Yet, little is known about the spatial scaling of alternate dimensions of diversity. Here, we provide empirical evidence for a relationship between the richness of acoustic traits emanating from the landscape, or soundscape richness, and the island area, which we term the Soundscape Area Relationship (SSAR). We show a positive relationship between the gamma soundscape richness and island area, with slope and R2-values of comparable magnitude to those reported in the literature. 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 disproportionate effects are an important underlying mechanism. We conclude that the scaling of biodiversity can be extended to the realm of ecoacoustics, implying soundscape metrics are sensitive to fundamental ecological patterns and useful to disentangle the complex mechanisms that drive them.

ecology↗

bioRxiv2022

A framework for the quantification of soundscape diversity using Hill numbers

O_LISoundscape studies are increasingly common to capture landscape-scale ecological patterns. Yet, several aspects of soundscape diversity quantification remain unexplored. Although some processes influencing acoustic niche usage may operate in the 24h domain, most acoustic indices only capture the diversity of sounds co-occurring in sound files at a specific time of day. Moreover, many indices do not consider the relationship between the spectral and temporal traits of sounds simultaneously. To provide novel insights into landscape-scale patterns of acoustic niche usage at broader temporal scales, we present a workflow to quantify soundscape diversity through the lens of functional ecology. C_LIO_LIOur workflow quantifies the functional diversity of sound in the 24-hour acoustic trait space. We put forward an entity, the Operational Sound Unit (OSU), which groups sounds by their shared functional properties. Using OSUs as our unit of diversity measurement, and building on the framework of Hill numbers, we propose three metrics that capture different aspects of acoustic trait space usage: (i) soundscape richness; (ii) soundscape diversity; (iii) soundscape evenness. We demonstrate the use of these metrics by (a) simulating soundscapes to assess if the indices possess a set of desirable behaviours; and (b) quantifying the soundscape richness and evenness along a gradient in species richness to illustrate how these metrics can be used to shed unique insights into patterns of acoustic niche usage. C_LIO_LIWe demonstrate that: (a) the indices outlined herein have desirable behaviours; and (b) the soundscape richness and evenness are positively correlated with the richness of soniferous species. This suggests that the acoustic niche space is more filled where taxonomic richness is higher. Moreover, species-poor acoustic communities have a higher proportion of rare sounds and use the acoustic space less effectively. As the correlation between the soundscape and taxonomic richness is strong (>0.8) and holds at low sampling intensities, soundscape richness could serve as a proxy for taxonomic richness. C_LIO_LIQuantifying the soundscape diversity through the lens of functional ecology using the analytical framework of Hill numbers generates novel insights into acoustic niche usage at a landscape scale and provides a useful proxy for taxonomic richness measurement. C_LI

ecology↗

bioRxiv2021

The catscape: spatial manifestation of a pet cat population with outdoor access

The domestic cat (Felis catus) is the most popular companion animal and the most abundant carnivore globally. It is also a pet with an immense ecological footprint, because even non-feral and food-subsidized cats are prolific predators. Whereas knowledge about the spatial behavior of individual domestic cats is growing, we still know little about how a local population of free-ranging pet cats occupies the landscape. Using a citizen science approach, we GPS-tagged 92 pet cats with outdoor access living in a residential area in southern Norway. The resulting position data allowed us to construct both individual home range kernels and a population-level utilization distribution. Our results reveal a dense predatory blanket that outdoor cats drape over and beyond the urban landscape. It is this population-level intensity surface - the "catscape" - that potential prey have to navigate. There were almost no gaps in the catscape within our residential study area and therefore few terrestrial refuges from potential cat predation. However, cats spent on average 79% of their outdoor time within 50 meters to their owners home, which suggests that the primary impact is local and most acute for wildlife in the vicinity to homes with cats. We discuss the catscape as a conceptual and quantitative tool for better understanding and mitigating the environmental impact of domestic cats.

ecology↗

bioRxiv2021

Biogeographic multi-species occupancy models for large-scale survey data

O_LIEcologists often seek to infer patterns of species occurrence or community structure from survey data. Hierarchical models, including multi-species occupancy models (MSOMs), can improve inference by pooling information across multiple species via random effects. Originally developed for local-scale survey data, MSOMs are increasingly applied to larger spatial scales that transcend major abiotic gradients and dispersal barriers. At biogeographic scales, the benefits of partial pooling in MSOMs trade off against the difficulty of incorporating sufficiently complex spatial effects to account for biogeographic variation in occupancy across multiple species simultaneously. C_LIO_LIWe show how this challenge can be overcome by incorporating pre-existing range information into MSOMs, yielding a biogeographic multi-species occupancy model (bMSOM). We illustrate the bMSOM using two published datasets: Parulid warblers in the United States Breeding Bird Survey, and entire avian communities in forests and pastures of Colombias West Andes. C_LIO_LICompared to traditional MSOMs, the bMSOM provides dramatically better predictive performance at lower computational cost. The bMSOM avoids severe spatial biases in predictions of the traditional MSOM and provides principled species-specific inference even for never-observed species. C_LIO_LIIncorporating pre-existing range data enables principled partial pooling of information across species in large-scale MSOMs. Our biogeographic framework for multi-species modeling should be broadly applicable in hierarchical models that predict species occurrences, whether or not false-absences are modeled in an occupancy framework. C_LI

ecology↗

bioRxiv2021

Above- and below-ground biodiversity responses to the prolonged flood pulse in central-western Amazonia, Brazil.

Amazonia encompasses forests that grow in areas that are periodically inundated by overflowing rivers. The inundation depth and duration vary according to the slope of the terrain, creating a flooding gradient. This gradient directly affects the biota, but the effect on soil organisms remains elusive. Here, we use DNA metabarcoding to estimate prokaryote and eukaryote diversity from soil and litter samples in a seasonally flooded forest and its adjacent unflooded forest in central-western Amazonia using 16S and 18S gene sequences, respectively. We characterize the below-ground diversity and community composition based on Amplicon Sequence Variants (ASVs) along the flooding gradient. We test for the relationship of soil biota with the flooding gradient, soil properties and above-ground woody plant diversity. The flooding gradient did not explain below-ground biodiversity. Nor was the below-ground diversity explained by the above-ground woody plant diversity. However, we found taxonomic groups not previously reported in Amazonian seasonally flooded forests. Also, the flooding gradient and woody plant diversity did, in part, explain the community composition of soil bacteria. Although the effects of the flooding gradient, soil properties and above-ground woody plant diversity is hard to quantify, our results thus indicate that flood stress could influence below-ground bacterial community composition.

ecology↗