Reconnecting the Web of Life: Rewiring and Network Robustness

Post provided by VINICIUS A. G. BASTAZINI, JEF VIZENTIN-BUGONI and JINELLE H. SPERRY

Esta publicação no blogue também está disponível em português

Species Loss and Cascading Effects

Scale-throated Hermit (Phaethornis eurynome). ©Pedro Lorenzo.

Scale-throated Hermit (Phaethornis eurynome). ©Pedro Lorenzo.

Minimising the effects the ongoing Anthropocene mass extinction has become one of the main challenges of our era. The data suggest that the current rate of species loss is 100–1,000 greater than the background rates seen in the geological record. “But does it really matter if species are lost?” This question has permeated social and political debates. It’s usually used to demean conservation efforts. But it has also intrigued conservation scientists.

We know that species don’t occur alone in their environment. They’re entangled by their interactions, forming complex networks. In these networks the loss of one species may result in the loss of other species that depend on it. This process is known as co-extinction. Estimates of the magnitude of past and future extinction rates have often failed to account for the interdependence among species and the consequences of primary species loss on other species though. Continue reading

Religando a rede da vida: Reconexões de interações e a robustez de redes ecológicas

Postagem fornecida por VINICIUS A. G. BASTAZINI, JEF VIZENTIN-BUGONI and JINELLE H. SPERRY

This post is also available in English

Perda de espécies e efeitos em cascata

Scale-throated Hermit (Phaethornis eurynome). ©Pedro Lorenzo.

Rabo-branco-de-garganta-rajada (Phaethornis eurynome). ©Pedro Lorenzo.

Minimizar os efeitos do atual processo de extinção em massa do Antropoceno se tornou um dos principais desafios da nossa era. Os dados sugerem que a taxa atual de perda de espécies é 100-1.000 vezes maior do que as taxas de fundo observadas no registro geológico. “Mas realmente importa se uma espécie é perdida?” Essa questão que permeia os debates sociais e políticos, geralmente para desqualificar os esforços de conservação, também tem intrigado os cientistas da conservação.

Sabemos que as espécies não ocorrem sozinhas em seu ambiente. Elas estão  interligadas por suas interações ecológicas, formando redes complexas. Nessas redes, a perda de uma espécie pode resultar em um efeito dominó, culminando na perda secundária de outras espécies. Esse processo é conhecido como co-extinção. As estimativas da magnitude das taxas de extinção passadas e futuras muitas vezes falharam em explicar a interdependência entre as espécies e as conseqüências da perda primaria de espécies. Continue reading

Researchers Use Drones to Weigh Whales

Below is a press release about the Methods in Ecology and Evolution article ‘Estimating body mass of free‐living whales using aerial photogrammetry and 3D volumetrics‘ taken from the British Ecological Society.

A southern right whale female rolling on her side and exposing her lateral side to the surface while gently touching her calf. ©Fredrik Christiansen

Researchers have devised a way to accurately estimate the weight of free-living whales using only aerial images taken by drones. By measuring the body length, width and height of free-living southern right whales photographed by drones, researchers were able to develop a model that accurately calculated the body volume and mass of the whales.

Because of their large size and aquatic life, previously the only way to obtain data on the body mass of whales was to weigh dead or stranded individuals.

The innovative method can be used to learn more about the physiology and ecology of whales. “Knowing the body mass of free-living whales opens up new avenues of research. We will now be able to look at the growth of known aged individuals to calculate their body mass increase over time and the energy requirements for growth. We will also be able to look at the daily energy requirements of whales and calculate how much prey they need to consume.” said Assistant Professor Fredrik Christiansen from Aarhus Institute of Advanced Studies in Denmark and lead author of the study. Continue reading

Meaningful Monitoring or Monitoring for the Sake of Monitoring? epower Helps You Tell the Difference

Post provided by REBECCA FISHER and GLENN R SHIELL

As environmental managers, we’re frequently asked to make judgements about the relative health of the environment. This is often difficult because, by its nature, the environment is highly variable in space and time. Ideally, such judgements should be informed by robust scientific investigation, or more precisely, the reliable interpretation of the resulting data.

Type I and Type II Errors

Even with robust investigations and good data, our interpretations can sometimes be wrong. In general, this happens when:

  • the investigation concludes that an impact has occurred, when in fact it hasn’t (Type I error)
  • fails to detect an impact, when an impact has actually occurred (Type II error).

Understanding the circumstances that lead to these errors is unfortunately complicated, and difficult unless you have a strong statistical background. Continue reading

Responding to New Weeds Needs Speed: Spatial Modelling with riskmapr Can Help

Post provided by JENS FROESE

Disclaimer: this post is NOT about the drug or the TV series, but about invasive alien plants. Yes, even biologists often refer to them as ‘weeds’.

Responding to New Weed Incursions

Responding to new weed incursions early and rapidly is very important. ©Panda8pie2

Responding to new weed incursions early and rapidly is very important. ©Panda8pie2

Weeds are a major threat to biodiversity and agricultural industries globally. New alien plant species are constantly introduced across borders, regions or landscapes. We know that some (such as those listed in the IUCN Global Invasive Species Database) are likely become problematic invasive weeds from experiences elsewhere.

When a weed is first introduced, population growth and spread is typically slow. This ‘invasion lag’ may be due to straightforward mathematics (population dynamics) as well as geography, environmental change or genetics. In any case, the lag period often presents the only window of opportunity where weed eradication or effective containment can be achieved. So, responding to new weed incursions early and rapidly is very important. Anyone who has ever battled with a bad weed infestation in their backyard knows it’s best to get in early and decisively! But decisions about where to target surveillance and control activities are often made under considerable time, knowledge and capacity constraints. Continue reading

Using Artificial Intelligence to Track Birds’ Dark-of-Night Migrations

Below is a press release about the Methods in Ecology and Evolution article ‘MistNet: Measuring historical bird migration in the US using archived weather radar data and convolutional neural networks‘ taken from the University of Massachusetts Amherst.

Wood thrush. ©CheepShot

On many evenings during spring and fall migration, tens of millions of birds take flight at sunset and pass over our heads, unseen in the night sky. Though these flights have been recorded for decades by the National Weather Services’ network of constantly-scanning weather radars, until recently these data have been mostly out of reach for bird researchers.

“That’s because the sheer magnitude of information and lack of tools to analyse it made only limited studies possible,” says artificial intelligence (AI) researcher Dan Sheldon at the University of Massachusetts Amherst. Continue reading

A Celebration of World Rivers Day

Post provided by Alfred Burian, Antonia Ford and Quentin Mauvisseau

Celebrating our river ecosystems world-wide on the 22nd of September.

Celebrating our river ecosystems world-wide on the 22nd of September. ©Bob Wick, BLM.

It’s the 22nd of September and that means it’s this year’s UN World Rivers Day! In over 60 countries around the globe events are going on today to bring attention to the many values of our waterways. And we, the Aquatic Ecology Special Interest Group of the BES, are joining in with the celebrations! We’re highlighting recent methodological advancements that will help us to manage and conserve our rivers in the future. So let’s get started…

Multiple Stressors and Molecular Tools

Today, human activities across the world are impacting rivers to varying degrees. As scientists, we frequently see the interaction of multiple different stressors such as flow regulations, pollution or climate change affecting our rivers. The combined impact of stressors like these may be worse than any of their individual impacts. To understand and manage the effect of them, we need cost-effective and reliable analytical tools that can capture site-specific and ecosystem-wide effects.

Recent methodological advances that will help us to achieve these goals often rely on the application of new or improved molecular tools. Emerging techniques include environmental DNA (eDNA) based applications to monitor endangered and invasive species as well as stable isotope ecology, which provides us with new insights into animal diets and energy flows through aquatic food webs. We’d like to take the opportunity to introduce some of the novel developments in both of these exciting fields. Continue reading

Solving the Midpoint Melee: Introducing New Methods for Plant Cover Classes

Post provided by KATHI IRVINE and TOM RODHOUSE

Collecting ordinal data. ©NPS

Or better yet, this post could be named ‘Our Cathartic Journey to Convince Ecologists to STOP Using the Midpoint Values for Analysing Plant Cover Classes’. Our work picks up where another recent Methods.blog post (Stuck between Zero and One) and Methods in Ecology and Evolution article (‘Analysing continuous proportions in ecology and evolution’) by Douma and Weedon left off. They introduced the benefits of using beta and Dirichlet regression. We’re going to tackle the sticky wicket of ordinal data. So, what should you do if you assign a range (like 0.2 to 0.3) instead of record a value (like 0.22) for a continuous proportion?

What is Ordinal Data?

It’s probably a good idea to start by defining the type of data we’re talking about. The best example is from plant surveys. Biologists visually assess the percentage of a pre-defined area covered by a certain plant species. They then record a ‘cover class value’ as an estimate of abundance. Each cover class value corresponds to the percentage of the area that is taken up by the plant in question (e.g., record a 0 for 0%, record a 1 for >0-5%, record a 2 for >5-25%, …, record a 6 for >95%). Continue reading

Researchers Develop Tools to Help Manage Seagrass Survival

Below is a press release about the Methods in Ecology and Evolution article ‘Analysing the dynamics and relative influence of variables affecting ecosystem responses using functional PCA and boosted trees: a seagrass case study‘ taken from Queensland University of Technology.

©Paul Asman and Jill Lenoble

A new QUT-led study has developed a statistical toolbox to help avoid seagrass loss which provides shelter, food and oxygen to fish and at-risk species like dugongs and green turtles. Seagrasses are a critical habitat that have been declining rapidly globally.

The research has been published in Methods in Ecology and Evolution describing key monitoring and management designs to maximise seagrass resilience to human activities. They will help to better inform seagrass dredging operations and development of coastal areas.

Led by statistical data researcher and lecturer Dr Paul Wu, from QUT’s School of Mathematical Sciences, the study identified and analysed factors that drove variations in a global seagrass dredging case study. Continue reading

Making Tags Less of a Drag: Optimising Biologging Devices with Computational Fluid Dynamics

Post provided by WILLIAM KAY

Drag and Biologging Devices

A harbour seal tagged with a biologging device. ©Dr Abbo van Neer

A harbour seal tagged with a biologging device. ©Dr Abbo van Neer

Michael Phelps is one of the most decorated Olympic athletes of all time and the world’s fastest swimmer. And yet, he could swim faster. Wearing the Speedo LZR Racer supersuit Michael Phelps could reduce his hydrodynamic drag, or water resistance, by upwards of 40%. That could increase his swim speed by more than 4%! In competition, that’s the difference between silver and gold. But, if Phelps forgot to remove his “drag socks” – cumbersome footwear designed to increase water resistance for strength training – his speed would be dramatically reduced. He’d be lucky to walk away with bronze!

Professional swimmers have adapted to the use of performance enhancing technologies to decrease their drag, but that’s nothing compared to the adaptations made by wild animals. Creatures in the marine environment have evolved incredible adaptations to decrease drag, such as extreme streamlining in marine mammals and seabirds. This allows them to move underwater as quickly and efficiently as possible. Seals, for example, are pretty ungainly on land, but in the water they’re sleek and rapid. They have a body shape designed to maximise speed while swimming.

When we study marine animals we often use tracking devices, which can be attached using harnesses, glue, or suction-cups. These ‘biologging devices‘, or tags, are similar to Fitbits. Attaching them to animals allows us to record, amongst other things, all of the animal’s movements and behaviours. This information is crucial to understanding their ecology and for improving their conservation management. Continue reading