Mark H. Mayfield

The Decline of Plant Collecting in the United States: A Threat to the Infrastructure of Biodiversity Studies

Abstract Collections of plant specimens are the basic infrastructure for all studies of plant diversity, but there is concern that plant collecting is in decline. We acquired collection data from a diverse sample of 71 herbaria to test whether there is a decrease in rates of local collecting in the United States. The recorded data were the decade of collection for all specimens of nine exemplar genera from the local region of the herbarium. All analyses showed evidence of a decline in local collecting. We found that the temporal pattern of collecting varied considerably from herbarium to herbarium, but that more herbaria showed a decreasing trend than an increasing trend. The total accumulation of specimens is in decline and only 21% of the sampled herbaria reached their peaks in local collecting activity in the last 20 years. Furthermore, two thirds of the herbaria acquired fewer locally-collected specimens in the last two decades than in the prior two. These trends were consistent over all size classes of herbaria and over herbaria from all regions, though they were less severe in the Mountain region herbaria. Tests for bias indicated that our sample of herbaria was more active than typical, thus our conclusions should be considered a conservative estimate of decline.

Implications of the Decline in Plant Collecting for Systematic and Floristic Research

In a companion paper in this issue, we have shown that plant collecting in the U.S. is in decline (Prather et al. 2004). We focused on the U.S. only because it was relatively easy for us to measure collecting there, but we are concerned that the decline in collecting may be pervasive worldwide. Because specimens are the fun damental records of biodiversity, we believe that this has serious ramifications in many arenas, particularly in systematic and floristic research, but also in conser vation biology, land management, and education, to name only the most obvious. Here we elaborate on the importance of collecting, even in the United States where the flora is relatively well-known. We further discuss some of the many causes of the decline, and encourage the systematics community to advocate con tinued plant collecting. Curators of collections and floristic researchers are

Reduced Genetic Variation in Populations of Black Cherry (Prunus serotina subsp. serotina, Rosaceae) at Its Western Range Limit in Kansas

Abstract We compared genetic variation at five nuclear simple sequence repeat loci between three populations of Black Cherry (Prunus serotina subsp. serotina) at the edge of its western range in Kansas to four populations from within the range interior. Although within-population expected heterozygosity did not differ between edge and core populations, allelic richness was significantly lower in the edge populations. This finding is consistent with a loss of rare alleles due to genetic drift in demographically unstable edge populations.