Tag Archives: richness

Re-Analysing Forest Biodiversity

The Gribskov Forest in Denmarkj, where this study took place (Image Credit: Malene Thyssen, CC BY-SA 3.0)

Biodiversity response to forest structure and management: Comparing species richness, conservation relevant species and functional diversity as metrics in forest conservation (2019) Lelli et al., Forest Ecology and Management, https://doi.org/10.1016/j.foreco.2018.09.057

The Crux

The classification of biodiversity is something that has become more and more relevant as the term ‘biodiversity’ has worked its way into the public’s vernacular. How we measure biodiversity can vastly influence our perception of it, and whilst we’ve previously looked at spatial interpretations of biodiversity on EcoMass, today I’m examining a paper that looks at interpretations of biodiversity by species groups.

Species richness (how many species are present in a given place) is often the go-to measurement for biodiversity. But it doesn’t always help when trying to conserve an ecosystem. For instance, we may wish to focus on certain types of species which are rare, or that preserve certain ecosystem functions. This paper looks at the differences in the effect of management on biodiversity, depending on which approach to biodiversity you take.

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Simulating the Evolution of Life in South America

Modeling the ecology and evolution of biodiversity: Biogeographical cradles, museums, and graves (2018) Rangel et al., Science, 244, DOI: 10.1126/science.aar5452

The Crux

Understanding the processes which drive biodiversity worldwide is never more crucial than now, in a world where biodiversity is shrinking rapidly. Biogeography, the study of species distributions, has come a long way, but there are still a lot of problems that need solving, including improving our understanding of the interactions between factors like climate change, dispersal abilities, fragmentation and species competition, to name a few.

This paper attempted to analyse some of the effects of those factors in concert, by producing a simulation of the evolutionary process in the world’s most biologically diverse continent, South America.

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Biological Annihilation

The sumatran orangutan, one of many species facing extinction in the earth's sixth mass extinction event

The sumatran orangutan, one of many species facing extinction in the earth’s sixth mass extinction event (Image Credit: Mike Pennington, CC BY SA 2.0)

Biological annihilation via the ongoing sixth mass extinction signaled by vertebrate population losses and declines (2017) Ceballos et al., Proceedings of the National Academy of Sciences of the USA, DOI: https://doi.org/10.1073/pnas.1704949114

Guest Post by Jonatan Marquez

The Crux

The rate at which species and populations have been going extinct in the last couple of centuries has well and truly earned the title of the planet’s sixth mass extinction event. However, most people rarely realize the severity of the situation. Hearing about the loss of two vertebrate species a year or having the last of some far-off species die out doesn’t see to cause much concern in the general public.

A species extinction is always preceded by population declines and extinctions. Perhaps highlighting the state of natural communities at this level might put the severity of the situation in better context. For example, the Living Planet Index (LPI) estimates that between 1970 and 2012, wildlife abundance has decreased by 58%. This paper focuses on the state and trends of populations of vertebrates by analysing i) the proportion undergoing declines or shrinkages, ii) the global distribution of population reduction events and iii) the general scale of population declines among mammal populations.

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The Chilly Cradle of Life

Species richness is much higher in waters near the equator, but do we see that in a phylogenic tree?

Species richness is much higher in waters near the equator, but do we see that in a phylogenetic tree? (Image Credit: Rich Brooks, CC BY 2.0)

An inverse latitudinal gradient in speciation rate for marine fishes (2018) Rabosky et al., Nature  doi:10.1038/s41586-018-0273-1

The Crux

The tropical regions of the Earth are the most species-rich and diverse ecosystems on the planet, with this diversity and species-richness declining as you move further and further from the equator. One hypothesis explaining this is that speciation rates are simply higher in the tropics, meaning that more species are evolving in a given time in the tropics than anywhere else. To test for this, the authors used the largest phylogenetic tree available and analyzed speciation rates (how many new species evolve from older species) per million years.

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