Hi all
I apologize for my dismissive comments about statistical models and the robust treatment of uncertainty. I am cognizant of: Pollock, K. H. (1982). A capture-recapture design robust to unequal probability of capture. The Journal of Wildlife Management, 752-757.

However, "Wild Bee decline threatens U.S Crop Production" stands on very shaky ground. In the very first sentence they state:

Wild bees are highly valuable pollinators. Along with managed
honey bees, they provide a critical ecosystem service by ensuring
stable pollination to agriculture and wild plant communities.

* There is no credible evidence that agriculture depends on wild bees at all. In fact, while bees in general have supposedly been declining, fruit production in the US has been skyrocketing. As I wrote in my article on "The Fall & Rise of the Honey Bee":

> An interesting point that the media reporters all miss (because they are not looking for it) is that fruit production has expanded while the numbers of bee colonies has fallen. The numbers went from 45 billion pounds in 1970 to 65 billion by 1990. The increase in the next twenty years, according to Dr. Nicholas Calderone, was from 100 million to 125 million tons of crops directly dependent on pollination. 

> Clearly the job of pollinating is getting done. This is a full time occupation for thousands of professional beekeepers, whose pay is closely tied to the value of the crop they pollinate. But beyond that, there are uncounted tens of thousands of beekeepers who keep small numbers of hives in every town and county. 

The paper in question goes on to state:

a National Research Council committee on the status of
pollinators in North America reported that conserving and improving
habitats for wild bees is important for ensuring continued
pollination services and food security

I have the NRC report in my hand, did they state that? They did say this:

Some studies demonstrate extensive pollination by wild pollinators
(Roubik, 1993, 1995), whereas others find little support for this assertion

What did they say about food security?

Pollinator declines, therefore, do not fundamentally threaten the world’s
caloric supplies. However, fruits and vegetables, which add diversity to the
human diet and provide essential nutrients, tend to depend heavily on pollinators

Although estimates of the proportion of the human diet that is attributable to animal
pollination are occasionally attempted and frequently cited, the proportion likely varies
among countries and regions and depends on dietary preferences, seasonal
availability, cultural practices, and economic status of consumers.

SEE ALSO:
Do Pollinators Contribute to Nutritional Health?
Alicia M. Ellis, Samuel S. Myers, Taylor H. Ricketts
PloS one 10.1 (2015): e114805.

* * *

However, all this may be beside the point. I think that trying to link wild bee conservation to agriculture is a huge mistake. This point is clearly made in 

Kleijn, D., Winfree, R., & al. (2015). Delivery of crop pollination services is an insufficient argument for wild pollinator conservation. Nature communications.

They state:

There is compelling evidence that more diverse ecosystems deliver greater benefits to people, and these
ecosystem services have become a key argument for biodiversity conservation. However, it is unclear
how much biodiversity is needed to deliver ecosystem services in a cost-effective way. Here we show
that, while the contribution of wild bees to crop production is significant, service delivery is restricted to
a limited subset of all known bee species. Across crops, years and biogeographical regions, crop-visiting
wild bee communities are dominated by a small number of common species, and threatened species
are rarely observed on crops. 

Conserving the biological diversity of bees therefore requires more than just ecosystem-service-based arguments.

When the economic pay-off from
ecosystem services is the main factor motivating conservation,
the cost-effective action is to conserve the subset of species that
provide the greatest return at relatively short timescales

First, few species
are needed to provide ecosystem services, with almost 80% of the
crop pollination provided by only 2% of bee species. Second, the
species currently contributing most to pollination service delivery
are generally regionally common species, whereas threatened
species contribute little, particularly in the most agriculturally
productive areas. Thus, a strictly ecosystem-service-based
approach to conservation would not necessitate the conservation
of threatened species.

too much focus on the services delivered by pollinators may lead to
adoption of practices that will not benefit species that could
potentially contribute under changing agricultural conditions nor
species that will never contribute to crop pollination.

Moral arguments
remain pivotal to supporting conservation of the larger portion of
biodiversity including threatened species that currently contribute
little to ecosystem service delivery.

If you are still reading, I remind you of the species for which the Xerces Society was named. It had no economic value whatever, but its loss is incalculable. 

> The species lived in coastal sand dunes of the Sunset District of San Francisco. The Xerces blue is believed to be the first American butterfly species to become extinct as a result of loss of habitat caused by urban development.

Bottom line:

> Ecologists and conservationists need to make these distinctions clear if we expect policy makers or land owners to defend species with no clearly defined economic value to humans. (Kleijn, D., Winfree, R., & al. 2015). 

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