Our new paper on extinction risk in marine and terrestrial species is out today in PNAS, “Range contraction enables harvesting to extinction.” Led by Matthew Burgess at UCSB, the research shows that shrinking distributions puts many animals at further risk from extinction as their abundance decline. While harvesters (fishers or hunters) are typically expected to stop harvesting when a species becomes rare and the costs of harvest become too high, contraction of a species into dense clusters can keep harvesting profitable, even at very low abundance. Examples of species with these contractions include Bengal tigers, Asian elephants, and bluefin tunas.
Baby fish float on ocean currents. So where do they go? Our paper out this week in Current Biology uses DNA to answer that question for clownfish in Papua New Guinea, and about 20 km is the simple answer. What’s especially exciting is that we show how very common and easily measured population genetic patterns called “isolation by distance” accurately measure the larval dispersal process. We validated our answer against observations of dispersal for hundreds of individual larvae (an incredibly time-consuming endeavor). Our findings help open the door to applying the isolation by distance method to a much wider range of marine species.
This work was the result of an exciting collaboration with Serge Planes, Geoff Jones, Simon Thorrold, Pablo Saenz-Agudelo, Michael Berumen, Michael Bode, and others.
Jim Morley has a new paper just online early in Global Change Biology (here). Studying marine fish and invertebrates of the coast of the southeast US, he found that winter temperatures quickly and predictably affect species’ distribution and abundance in the following year. In particular, we found a greater abundance of southern, warm-water species following mild winters. We also found that these impacts cascade up to affect fisheries catches for many species. Interestingly, these responses appear in a region that has not been warming over the last couple decades, though 1-3 °C of warming is expected by the end of this century. Warmer winters likely will result in increased abundance of species with more southern affinities, such as white and pink shrimp, southern hake, and star drum.
With a great set of co-authors, including Eli Fenichel at Yale, we just published a paper in Nature Climate Change showing how to measure the impacts of climate change on wealth. Our previous work, including this, has shown how climate pushes natural resources around. In this new paper, we show that those movements change who gets access to resources, and how those movements affect wealth. As important, or even more important, than the quantity of resources, however, is the quality of a region’s resource management, existing institutions, and fishing regulations. Places with strong resource management stand to gain the most from climate-driven changes in resource distribution.
To make these points, we use a hypothetical example with two fishing ports.
This is one of the initial publications from our NSF Coastal SEES grant examining the impacts of climate change on fish and fisheries.
This figure shows three of the key sources of uncertainty in any projection, using sea surface temperature as an example: the model used to make the projection (blue), the climate change scenario followed (green), and irreducible variability in the model (orange). The graph shows how natural variability dominates over the next couple decades, but the scenario of greenhouse gas emissions is very important by the end of the century.
Fishing and climate change: two of the largest human impacts on the ocean. But how do they interact? In a new paper just out in Ecosphere, Emma Fuller, Eleanor Brush, and I use an ecological model to build some intuition. We looked specifically at how fishing affects the ability of species to shift their distributions fast enough to keep up with climate velocity. Two main take-home messages:
Fishing the leading edge of a species range has the biggest impact (this also tends to be where fishing is unregulated….)
Marine protected areas (MPAs) can actually make it harder for species to keep up with climate if the MPAs concentrate fishing effort in narrower areas.
We have a new paper out in Proceedings B, “Fishing, fast growth and climate variability increase the risk of collapse.” Analyzing data from fisheries around the world, we show that patterns in the ocean are nearly the opposite of those on land. Slow-growing species like lions and tigers may be most at risk of extinction on land, but in the ocean, it’s the “rabbits” that are most sensitive. We find that fast-growing species like flounder and sardines are more than three times more likely to collapse when they experience overfishing than their slower-growing cousins. Populations that experience strong climate variability are also more at risk.
Tim Essington also had a nice paper exploring some of these patterns among small pelagic species earlier this year. Definitely worth a read, plus the following discussion (here and here).
Malin got interviewed today for the evening news on New Jersey public television (broadcast at 6, 7:30, and 11pm). The Stellar’s sea cow may be gone, but there’s much we can do to avert future ocean extinctions. This is on our Science paper out two weeks ago.