A plant’s adaptive traits don’t follow climate conditions as you might expect

27 03 2020

mountain

Just a quick post today, my last one for March. Like probably most of you, I’ve been trying to pretend to be as normal as possible despite the COVID-19 surrealism all around me. But even COVID-19 has shifted my research to a small degree.

But I’m not going to talk about the global pandemic right now (I can almost hear the collective sigh of relief). Instead, I’m going to go back to topic and discuss a paper that I’ve just co-authored.

Last year I went to China’s Yunnan Province where I met some fantastic colleagues at the Xishuangbanna Tropical Botanical Garden who were doing some very cool stuff with the variation in plant functional traits across environmental gradients.

Well, those colleagues invited me to participate in one those research projects, and I’m happy to say that the result has just been published in Forests.

Measuring the functional traits of different alpine trees species in the Changbai Mountains of far north-eastern China (no, I didn’t get to go there), the research set out to test how these varied among species and elevation.

Of course, one expects that different trees use different combinations of traits to survive the rigours of mountain life (high variation in temperature, freezing, wind, etc.), but generally speaking, you might expect things like xylem vessel diameter and density to change more or less monotonically (i.e., changing in a consistent manner as elevation rises or falls). This is because trees should adapt their traits to the local conditions as best they can. Read the rest of this entry »





Influential conservation ecology papers of 2019

24 12 2019

Bradshaw-Waves breaking on rocks Macquarie Island
As I’ve done for the last six years, I am publishing a retrospective list of the ‘top’ 20 influential papers of 2109 as assessed by experts in F1000 Prime (in no particular order). See previous years’ lists here: 20182017, 20162015, 2014, and 2013.

 

 

 

 

 

 

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Koala extinctions past, present, and future

12 06 2019
Koala

Photo by John Llewelyn

Koalas are one of the most recognised symbols of Australian wildlife. But the tree-living marsupial koala is not doing well throughout much of its range in eastern Australia. Ranging as far north as Cairns in Queensland, to as far west as Kangaroo Island in South Australia, the koala’s biggest threats today are undeniably deforestation, road kill, dog attacks, disease, and climate change.

With increasing drought, heatwaves, and fire intensity and frequency arising from the climate emergency, it is likely that koala populations and habitats will continue to decline throughout most of their current range.

But what was the distribution of koalas before humans arrived in Australia? Were they always a zoological feature of only the eastern regions?

The answer is a resounding ‘no’ — the fossil record reveal a much more complicated story.

Read the rest of this entry »





Save a jaguar by eating less meat

8 10 2018
Kaayana

My encounter with Kaayana in Kaa-Iya National Park in the Bolivian Chaco. Her cub was around but cannot be seen in the photo

I was trapped. Or so I thought.

The jaguar came towards me on the dirt road, calmly but attentively in the dusky light, her nearly full grown cub behind her. Nervous and with only a torch as defence, I held the light high above my head as she approached, trying to look taller. But she was merely curious; and, after 20 minutes, they left. I walked home in the thickening darkness, amazed at having come so close to South America’s top predator. We later named this mother jaguar ‘Kaayana’, because she lives inside Kaa-Iya National Park in the Bolivian Chaco. My fascination with jaguars has only grown since then, but the chances of encountering this incredible animal in the wild have shrunk even since that night.

A few years after that encounter, I’m back to study jaguars in the same forest, only now at the scale of the whole South American Gran Chaco. Jaguars are the third largest cats in the world and the top predators across Latin America. This means that they are essential for keeping ecosystems healthy. However, they are disappearing rapidly in parts of their range.

Understanding how and where the jaguar’s main threats — habitat destruction and hunting — affect them is fundamental to set appropriate strategies to save them. These threats are not only damaging on their own, but they sometimes act simultaneously in an area, potentially having impacts that are larger than their simple sum. For instance, a new road doesn’t only promote deforestation, it also increases hunters’ ability to get into previously inaccessible forests. Similarly, when the forest is cut for cattle ranching, ranchers often kill jaguars for fears of stock loss.

Kaayana & kittens

Kaayana was seen years later by Daniel Alarcón, who took much better photos of her and her new cubs

However, the interactions between these threats are still not fully understood. In our new study, just published in the journal Diversity and Distributions, we developed a new framework to quantify how and where habitat destruction and hunting risk acted together over three decades, at the expense of highly suitable jaguar habitat in the Gran Chaco. We also analyzed how well the different Chaco countries — Bolivia, Paraguay and Argentina — and their protected areas maintained key jaguar habitat. Read the rest of this entry »





Legacy of human migration on the diversity of languages in the Americas

12 09 2018

quechua-foto-ale-glogsterThis might seem a little left-of-centre for CB.com subject matter, but hang in there, this does have some pretty important conservation implications.

In our quest to be as transdisciplinary as possible, I’ve team up with a few people outside my discipline to put together a PhD modelling project that could really help us understand how human colonisation shaped not only ancient ecosystems, but also our own ancient cultures.

Thanks largely to the efforts of Dr Frédérik Saltré here in the Global Ecology Laboratory, at Flinders University, and in collaboration with Dr Bastien Llamas (Australian Centre for Ancient DNA), Joshua Birchall (Museu Paraense Emílio Goeldi, Brazil), and Lars Fehren-Schmitz (University of California at Santa Cruz, USA), I think the student could break down a few disciplinary boundaries here and provide real insights into the causes and consequences of human expansion into novel environments.

Interested? See below for more details?

Languages are ‘documents of history’ and historical linguists have developed comparative methods to infer patterns of human prehistory and cultural evolution. The Americas present a more substantive diversity of indigenous language stock than any other continent; however, whether such a diversity arose from initial human migration pathways across the continent is still unknown, because the primary proxy used (i.e., archaeological evidence) to study modern human migration is both too incomplete and biased to inform any regional inference of colonisation trajectories. Read the rest of this entry »





Two new postdoctoral positions in ecological network & vegetation modelling announced

21 07 2017

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With the official start of the new ARC Centre of Excellence for Australian Biodiversity and Heritage (CABAH) in July, I am pleased to announce two new CABAH-funded postdoctoral positions (a.k.a. Research Associates) in my global ecology lab at Flinders University in Adelaide (Flinders Modelling Node).

One of these positions is a little different, and represents something of an experiment. The Research Associate in Palaeo-Vegetation Modelling is being restricted to women candidates; in other words, we’re only accepting applications from women for this one. In a quest to improve the gender balance in my lab and in universities in general, this is a step in the right direction.

The project itself is not overly prescribed, but we would like something along the following lines of inquiry: Read the rest of this entry »





It’s not all about temperature for corals

31 05 2017

CB_ClimateChange6_Photo

Three of the coral species studied by Muir (2): (a) Acropora pichoni: Pohnpei Island, Pacific Ocean — deep-water species/IUCN ‘Near threatened’; (b) Acropora divaricate: Maldives, Indian ocean — mid-water species/IUCN ‘Near threatened’; and (c) Acropora gemmifera: Orpheus Island, Australia — shallow-water species/IUCN ‘Least Concern’. The IUCN states that the 3 species are vulnerable to climate change (acidification, temperature extremes) and demographic booms of the invading predator, the crown-of-thorns starfish Acanthaster planci. Photos courtesy of Paul Muir.

Global warming of the atmosphere and the oceans is modifying the distribution of many plants and animals. However, marine species are bound to face non-thermal barriers that might preclude their dispersal over wide stretches of the sea. Sunlight is one of those invisible obstacles for corals from the Indian and Pacific Oceans.

If we were offered a sumptuous job overseas, our professional success in an unknown place could be limited by factors like cultural or linguistic differences that have nothing to do with our work experience or expertise. If we translate this situation into biodiversity terms, one of the best-documented effects of global warming is the gradual dispersal of species tracking their native temperatures from the tropics to the poles (1). However, as dispersal progresses, many species encounter environmental barriers that are not physical (e.g., a high mountain or a wide river), and whose magnitude could be unrelated to ambient temperatures. Such invisible obstacles can prevent the establishment of pioneer populations away from the source.

Corals are ideal organisms to study this phenomenon because their life cycle is tightly geared to multiple environmental drivers (see ReefBase: Global Information System for Coral Reefs). Indeed, the growth of a coral’s exoskeleton relies on symbiotic zooxanthellae (see video and presentation), a kind of microscopic algae (Dinoflagellata) whose photosynthetic activity is regulated by sea temperature, photoperiod and dissolved calcium in the form of aragonite, among other factors.

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