MNLA elevates four to principal, moving the firm forward in leadership

Manhattan, NY MNLA, the award-winning landscape architecture firm, has elevated Alexis Gagné, Dan Yannaccone, Johanna Phelps, and Martha Desbiens to the role of principal. This progression marks a milestone in MNLA’s ongoing evolution by reflecting the firm’s commitment to cultivating a collaborative, values-driven practice and advancing the next generation of design leadership.

The four new principals join Nielsen, Molly Bourne, and Rob DeMarco in leading MNLA’s next chapter, building on the firm’s decades-long foundation of design excellence. Together, their collective direction ensures stability across the firm’s project portfolio and empowers teams to deliver transformative, human-centered landscapes.

Alexis Gagné, LLA, ASLA, known for her thoughtful approach to urban landscapes, has led numerous high-profile projects and continues to advance MNLA’s mission to enrich public life in shared spaces through design that balances form, function, and community impact.

Dan Yannaccone, LLA, ASLA, WEDG, has over two decades of expertise in resilient site planning and ecological design, guiding complex landscape concepts to fruition.

Johanna Phelps, RLA, ASLA, WEDG, has designed and directed some of the firm’s most notable campus and institutional projects, steering teams toward innovative, contextually grounded solutions across various geographic markets. 

Martha Desbiens, LLA, ASLA, SITES AP, WEDG, has been instrumental in expanding MNLA’s academic and healthcare practice, integrating environmental performance and design excellence to support learning, wellness, and community connection.

“This elevation represents both continuity and renewal,” said founding principal Signe Nielsen. “Each of these talented leaders embodies MNLA’s core principles of transformation, inclusivity, and advocacy. Their elevation reflects years of dedication to our clients, our projects, and our people—and I couldn’t be more confident in their collective ability to guide MNLA into the future.”

Since joining, Gagné, Yannaccone, Phelps, and Desbiens have each played roles in shaping the firm’s portfolio and culture:

“As MNLA continues to grow, we remain deeply committed to our founding values and to the collaborative spirit that defines our work,” said the principals in a joint statement. “This transition reflects both the strength of our practice and the enduring influence of Signe’s mentorship and guidance, which continues to inspire the firm’s forward path.”

MNLA’s leadership model emphasizes its ongoing dedication to advocacy and transformation through design principles that have guided the firm for more than three decades and continue to shape its approach to creating meaningful landscapes that serve people, place, and the planet.