Orchid (Orchidaceae) decline in the Catoctin Mountains, Frederick County, Maryland as documented by a long-term dataset

• Published in: Biodiversity and conservation Vol. 23; no. 8; pp. 1965 - 1976
• Main Authors: Knapp, Wesley M, Wiegand, Richard
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer-Verlag 01.07.2014; Springer Netherlands; Springer; Springer Nature B.V
• Subjects: Animal, plant and microbial ecology; Applied ecology; Biodiversity; Biological and medical sciences; Biomedical and Life Sciences; Census; census data; Climate Change/Climate Change Impacts; Conservation biology; Conservation Biology/Ecology; Conservation, protection and management of environment and wildlife; data collection; Deer; Ecological succession; Ecology; Endangered & extinct species; Endangered species; Fundamental and applied biological sciences. Psychology; General aspects; Habitats; Herbivores; Herbivory; herds; least squares; Life Sciences; Mountains; Odocoileus virginianus; Orchidaceae; Original Paper; Plant ecology; Plant succession; Platanthera ciliaris; Population number; population size; Protection and preservation; Threatened species; White-tailed deer; Wildlife conservation; wildlife management; Woody plants; Maryland; United States; North America; America; USA, Maryland, Frederick Cty; USA, Maryland; Deer herbivory; Habitat management; Conservation; Rare species; Monocotyledones; Herbivorous; Long term; Vertebrata; Mammalia; Mountain; Orchidaceae; Angiospermae; Cervidae; Spermatophyta; Habitat; Artiodactyla; Ungulata
• DOI: 10.1007/s10531-014-0698-2
• ISSN: 0960-3115

A 41-year study (1968–2008) of the orchids of the Catoctin Mountains, Frederick County, Maryland reveals that 19 of 21 species have experienced precipitous declines. Four of these species are currently considered Threatened or Endangered by the State of Maryland and another two are considered Rare. Annual census data at 167 sites from throughout the Catoctin Mountains on protected and unprotected lands (private and public) show a loss of three species from the study area, a decline of >90 % (ranging from 99 to 91 %) in seven species, and a decline of <90 % (ranging from 51 to 87 %) for nine species. Each species was analyzed using Ordinary Least Squares Analysis to show trends and document corresponding R² and p values. We tested the hypothesis that this decline is due to intensified herbivory by white-tailed deer. The overall orchid census data is significantly inversely-correlated (R = −0.93) to the white-tailed deer harvest data of Frederick County (a surrogate for population size), which includes the entirety of the study area. Platanthera ciliaris showed a huge expansion at a single site explicitly managed for this species otherwise this orchid showed a decline similar to the other species. Proper management is critical for the continuation of the orchid species in this study, be it control of the white-tailed deer herd or combating woody plant succession in the case of P. ciliaris.