François Bareille

Looks like the American Journal of Agricultural Economics is now on Bluesky 👀

Good news for ag econ folks.

Uncovering renewable energy policy impact channels on land values, the local farm structure, and farmland heterogeneity Germany's Renewable Energy Sources Act (REA), enacted in 2000 and subsequently amended, subsidized national renewable energy production with fixed feed-in tariffs for renewable energy sources (RE) fr...

New AJAE paper:

"Uncovering renewable energy policy impact channels on land values, the local farm structure, and farmland heterogeneity,"

by Lars Isenhardt, Stefan Seifert, Saskia Wolff, Tobia Lakes, Marten Graubner, Axel Werwatz, Silke Hüttel,

onlinelibrary.wiley.com/doi/10.1002/...

📢 Out now in the ❄️January 2026 issue❄️ of #JAERE! 📢
"Climate Change and Field-Level Crop Quality, Yield, and Revenue" by Sarah C. Whitnall ( @sarahwhitnall.bsky.social ) and Timothy K.M. Beatty.
Read it here: buff.ly/WXzI813
📈📉 #Econsky

A little bit late, but I'm looking to hire a postdoc at Cornell to measure the private value of soil health improvements in US ag. A 2-year gig.

Well suited for an ag/resource economist or data scientist w/ interests in soil health and solid programming & econometric chops.

ad coming soon!

Message for policymakers:
You don’t need new instruments — better design of exisiting schemes to foster cooperation may be enough.
🎯Small institutional changes in enrollment rules can deliver large biodiversity gains!

[End of thread]

⚠️Not all cooperation rules are equal.

Open-list ABs (where the size of cooperating groups is not restricted by existing members, in the standard open-membership spirit) generate *larger coalitions*, *more connected habitats*, and *more cost-effective conservation*.

[7/8]

Main result:
👉 Allowing cooperation increases biodiversity outcomes by 10–45%, relative to individual schemes with identical payments.

[6/8]

We compare 4 policy instruments to conserve biodiversity:
1️⃣ standard homogeneous payments,
2️⃣ individual agglomeration bonuses (ABs),
3️⃣ collective ABs with closed membership (as in our previous AJAE paper),
4️⃣ collective ABs with open membership (a new instrument)

[5/8]

Methodologically, we combine:
1️⃣ a spatial ecological-economic model where regulators formulate payments in alternative schemes,
2️⃣ a coalition formation game,
so landowners choose both *how much* to conserve and *with whom* to cooperate in this process.

[4/8]

We ask a simple question:
👉what is the value of cooperation for biodiversity conservation?

Or, say differently: How much biodiversity comes from cooperation itself, holding payments constant?

[3/8]

Collective conservation schemes are gaining attention everywhere — but most research focuses on how to design payments to conserve biodiveristy, not on how cooperation actually emerges in response to these incentives.
We argue this is a blind spot.

[2/8]

Promise made, promise kept.
Here’s a short thread on our new Ecological Economics paper (with @mzavalloni.bsky.social ):
"The value of cooperation for biodiversity conservation policies"

👉Link: sciencedirect.com/science/articl
e/pii/S0921800925003842

[1/8]

New in Ecological Economics !

Link for "A meta-analysis on the productive value of crop biodiversity" (American Journal of Agricultural Economics, with B. Largier):

onlinelibrary.wiley.com/doi/10.1002/...

Link for "The value of cooperation for biodiversity conservation policies" (Ecological Economics, with
@mzavalloni.bsky.social):

www.sciencedirect.com/science/arti...

After years in the climate-econ trenches, I’ve resurfaced with two new biodiversity papers out in Ecological Economics (with @mzavalloni.bsky.social) and American Journal of Agricultural Economics (with B. Largier)

More detailed threads soon (once I’ve recovered from the proofs).

Overall, increasing internal bonuses over external ones thus allows improving AB cost-effectiveness. Interestingly, landowners mostly enroll individually in such differentiated ABs.

As such, habitat agglomeration doesn’t always need cooperation—it just needs smart incentives.

10/10

To overcome this issue, the regulator must raise external bonuses high enough to make each landowner better off independently.

This makes external conservation more expensive than internal bonuses. Cooperation is costly!

9/10

External bonuses are trickier: both landowners must find it individually worthwhile to conserve. If just one of them faces a higher cost than the bonus, the deal collapses and the AB does not work—because they can’t compensate each other (while they can within landholdings)

8/10

Here’s the intuition:

For internal bonuses, only the total surplus from the two plots matters. If the combined bonus exceeds the combined opportunity cost, the landowner will conserve both plots—no matter how the gains are split.

7/10

Our simulations—calibrated with French data—show a clear pattern:

When the regulator's budget is limited, undifferentiated ABs (same internal & external bonuses) perform best.
But as the budget grows, prioritizing internal bonuses becomes increasingly cost-effective. Why?

6/10

So we ask ourselves whether regulators should differentiate between these two types of bonuses?

To answer, we develop a spatially explicit ecological-economic game, with landowners choosing whether to cooperate and what to conserve, under a fixed regulatory budget.

5/10

Why? Because external bonuses involve cooperation problems: two landowners must agree to conserve plots side-by-side.

Internal bonuses avoid this: a single landowner can conserve multiple adjacent plots without negotiating with others. This improves AB cost-effectiveness.

4/10

Most ABs reward landowners when two conserved plots are adjacent, regardless of who owns the plots.

Yet, the two plots can be either on the same landholding (internal bonus), or on different landholdings (external bonus).

Raphaël and I show that this distinction matters.

3/10

This work extends my 2023 paper with @mzavalloni.bsky.social in AJAE, where we showed that landowners enroll into agglomeration bonus (AB) in small groups—not the idealized "grand coalition" often assumed in previous AB models.

That finding led us to rethink how incentives work.

2/10

Individual versus group-level agglomeration bonuses to conserve biodiversity Agglomeration bonuses (ABs) are payments conditional on the contiguity of landowners’ conservation areas. We study whether differentiating the bonuses…

Thrilled to share my new paper in @jeem-econ.bsky.social
, coauthored with Raphaël Soubeyran:

We explore how differentiating agglomeration bonus *within* vs. *between* landholdings can make biodiversity policies on habitat agglomeration more effective.

📄 sciencedirect.com/science/arti...

🧵 1/10

I had the chance to present my ongoing work "Adapting to climate change with (in)complete land rights: Evidence from the Greece land registry reform" this morning at the University degli studi of Milano. Plenty of good comments from the audience!

Thanks for the engaging discussion ☺️

Cela semble absurde, et j’ai été choqué la première fois que je l’ai compris, mais la France – il n'y a pas d'autre mot – est bien un paradis fiscal pour milliardaire

Explications détaillées 🧵

Malheureusement le devoir m’appelle à Milan ! (Tu viens à l’IAERE à Rome la semaine prochaine ?)

I had the chance to present some of my works at the University of Trento this morning. Very glad to the economics department for the invitation 🙂

Very nice people and landscapes there!