The Decline of the National Arboretum

DSC01199In a post that many local lepsters will have seen, colleague and DC count organizer Tom Stock observed after the count on the 16th:

>>It was no surprise to me that this year’s DC NABA Annual Butterfly Count last Saturday (July 16) at the Arboretum and Kenilworth Aquatic Garden yielded both low diversity (22 species) and even lower numbers of individuals than in most previous years (107). That’s been the rule around here this month. On the bright side, we had a great turnout, and found a species that before last year hadn’t even been recorded in the District – Dion Skipper. Last year, several Dions were seen at Kenilworth Aquatic Garden after a first record for DC was discovered there the week before the count in August. This year, we found a Dion in a patch of dogbane on the grounds of the Arboretum! A first for that location.

Our list for the day appears below. But here, I feel compelled to offer a few comments on the sad state of pollinator stewardship at the United States National Arboretum – which one would expect to be a national showplace for educational experiences focused on pollinators – including butterflies – and the critical role they play in plant propagation. In fact, not once in the Arboretum‘s Strategic Plan 2013-2017 does the word “pollinator” appear, or “butterfly” or “bee” for that matter. All this despite a high-profile pollinator initiative launched just last month by the U.S. Department of Agriculture, which manages the Arboretum.

http://www.usda.gov/wps/portal/usda/usdamediafb?contentid=2016/06/0152.xml&printable=true&contentidonly=true

What met my eyes this past Saturday at the Arboretum was stark evidence of the absence from its strategic plan of any mention of pollinators. In fact, the Arboretum appears to have largely abandoned its historical commitment to and management practices for pollinator education and conservation. A case in point: The butterfly garden is no longer viable. A construction project has consumed much of it – and eliminated all the senna in the garden, along with a hedge of Buddleia. A hop vine in need of a trellis is languishing on the ground. Plantings between the butterfly space and the fenced in youth garden is under cultivation at the peak of butterfly season (or what would be the peak in any other year); this area has in past years supported milkweed, dogbane, partridge pea and other butterfly host and nectar plants.

I found it particularly distressing that the garden staff apparently has engaged in a concerted effort to rid the garden of lamb’s-quarter (Chenopodium), the host plant for a declining species, Hayhurst’s Scallopwing. The late Bob Speaker had during his stewardship of the garden carefully nurtured a lush growth of Chenopodium, and the butterfly garden was one of the few reliable places in the area to find the Scallopwing. None of us found ANY Chenopodium or Scallopwings Saturday. And so, as a result of some very poor pollinator-blind gardening practices, it appears likely that a butterfly species has been eradicated from the Arboretum. This is an unfortunate stain on Bob Speaker’s legacy, as is the overall neglect of the once-thriving butterfly garden.

Shame on the United States National Arboretum.<<

The butterfly garden isn’t the only habitat that’s suffered; many of the extensive field and pondside habitats have been mowed to the nubbins where they used to support extensive native wildflower stands.  The Arboretum seems to be aiming for a “park” look rather than a “natural area” look.

And this is their prerogative, of course:  The Arboretum is a working research collection of USDA’s Agricultural Research Service, and many of more than 100 commercial horticultural introductions the Arboretum has made to modern gardens originated right here.  There’s always been something of a tension between the Arboretum’s sometimes-conflicting roles as horticultural research facility, recreational landscape, natural area, and public garden.

But the rapid decline of the Washington Butterfly Garden is an object lesson in what it takes to establish and maintain plantings for the benefit of pollinators.  Under the late Bob Speaker, this small garden was not a native garden, although it did have many native larval food plants, but was established to attract and support the maximum diversity of butterfly and moth species.  And over the years, it has been spectacularly successful — as Tom mentioned, it’s one of the only local places to host a reliable colony of Hayhurst’s Scallopwing, in addition to regularly offering regular uncommon sightings like Long-tailed Skipper, White M Hairstreak, and Little Yellow.  The caterpillar food plants for Scallopwing and Little Yellow have been pulled up or plowed under, and adult nectar sources for White M and Long-tailed Skipper have been drastically reduced.

In this case, it appears the Washington Youth Garden has benefited at the expense of the Butterfly Garden — about half the footprint has been added to the Youth Garden plantings, and any “weeds” have been eliminated by Youth Garden volunteers unfamiliar with butterfly host plants.  Visitors to the DC area who hope to see a broad sampling of the region’s butterfly species who are accustomed to finding them at the Arboretum will need to look elsewhere.

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