Essential predators

21 11 2012

© C. Hilton

Here at ConservationBytes.com, My contributors and I have highlighted the important regulating role of predators in myriad systems. We have written extensively on the mesopredator release concept applied to dingos, sharks and coyotes, but we haven’t really expanded on the broader role of predators in more complex systems.

This week comes an elegant experimental study (and how I love good experimental evidence of complex ecological processes and how they affect population persistence and ecosystem stability, resilience and productivity) demonstrating, once again, just how important predators are for healthy ecosystems. Long story short – if your predators are not doing well, chances are the rest of the ecosystem is performing poorly.

Today’s latest evidence comes from on an inshore marine system in Ireland involving crabs (Carcinus maenas), whelks (Nucella lapillus), gastropd grazers (Patella vulgata, Littorina littorea and Gibbula umbilicalis), mussels (Mytilus edulis) and macroalgae. Published in Journal of Animal Ecology, O’Connor and colleagues’ paper (Distinguishing between direct and indirect effects of predators in complex ecosystems) explains how their controlled experimental removals of different combinations of predators (crabs & whelks) and their herbivore prey (mussels & gastropods) affected primary producer (macroalgae) diversity and cover (see Figure below and caption from O’Connor et al.). Read the rest of this entry »





Rise of the phycologists

22 09 2011

Dead man's fingers (Codium fragile) - © CJA Bradshaw

I’ve had an interesting week. First, it’s been about 6 years since I was last in Japan, and I love coming here; the food is exquisite, the people are fantastic (polite, happy, accommodating), everything works (trains, buses, etc.) and most importantly, it has an almost incredible proportion of its native forests intact.

But it wasn’t for forests that I travelled to Japan (nor the sumo currently showing on the guest-room telly where I’m staying – love the sumo): I was here for a calcareous macroalgae workshop.

What?

First, what are ‘macroalgae’, and why are some ‘calcareous’? And why should anyone in their right mind care?

Good questions. Answers: 1. Seaweeds; 2. Many incorporate calcium carbonate into their structures as added structural support; 3. Read on.

Now, I’m no phycologist (seaweed scientist), but I’m fascinated by this particular taxon. I’ve written a few posts about their vital ecological roles (see here and here), but let me regale you with some other important facts about these amazing species.

Some Japanese macroalgae - © CJA Bradshaw

There are about 12,000 known species of macroalgae described by phycologists, but as I’ve learnt this week, this is obviously a vast underestimate. For most taxa that people are investigating now using molecular techniques, the genetic diversity is so high and so geographically structured that there are obviously a huge number of ‘cryptic’ species within our current taxonomic divisions. This could mean that we’re out by up to a factor of 2 in the number of species in the world.

Another amazing fact – about 50 % of all known seaweed species are found in just two countries – Japan and Australia (hence the workshop between Japanese and Australian phycologists). Southern Australia in particular is an endemism hotspot.

Ok. Cool. So far so good. But so what? Read the rest of this entry »








Follow

Get every new post delivered to your Inbox.

Join 6,692 other followers

%d bloggers like this: