Augmenting Populations of Spalding’s Catchfly (Silene spaldingii) Populations in Northwest Montana

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Spalding’s catchfly (Silene spaldingii, Caryophyllaceae) is considered threatened throughout its range in the Columbia Plateau under the U.S. Endangered Species Act (USFWS 2007). Many populations, especially in the center of the range are small and will need to increase in size in order to attain recovery. Natural recruitment of Spalding’s catchfly is sporadic at some sites (Lesica 1997), and inbreeding may predominate in small populations (Lesica 1993, Baldwin and Brunsfeld 1995), both factors that can lead to lowered population growth. Humanmediated population augmentation can result in more rapid population growth by directly adding individuals and indirectly reducing inbreeding depression (Guerrant 1996). <br>

Transplanting seedlings is often a more successful reintroduction strategy than sowing seeds directly (Guerrant and Kaye 2007, Reckinger et al. 2010, Godefroid et al. 2011, Albrecht and Maschinski 2012). Unfortunately little is known about establishing nursery-grown stock of Spalding’s catchfly. Cold-stratification enhances germination of catchfly seed (Lesica 1993), but protocols for post-germination culture have not been developed. The purpose of this study was to develop restoration protocols for Spalding’s catchfly usable in Montana and adaptable in other portions of the species range. In particular, we determined how five factors affect survival and growth of nursery-grown stock in the field: (1) age of outplanted seedlings; (2) soil type used in culture; (3) watering in the field; (4) type of nursery container; and (5) date of outplanting. <br>

Spalding’s catchfly is a long-lived iteroparous herb with one or few vegetative or flowering stems arising from a caudex surmounting a long taproot (Hitchcock and Maguire 1947). Plants flower in late June through August and set seed in August and September, depending on location. Rosettes are formed the first years after germination after which vegetative stems are produced. Vegetative and flowering plants emerge in mid- to late-May and senesce in September. Spalding’s catchfly demonstrates prolonged dormancy in which plants do not appear or have only ephemeral, above-ground vegetation for one or more consecutive summers (Lesica 1997). Prolonged dormancy of germinated plants is common, with bouts of dormancy usually lasting 1–2 years (Lesica 1997, Lesica and Crone 2007). <br>

We conducted our study on Wildhorse Island at the southwest end of Flathead Lake, 20 km north of Polson in Lake County, Montana, U.S. (47° 50' N, -114° 12' W) at 985 m in elevation. Vegetation at the study site is grassland dominated by rough fescue (Festuca campestris), Idaho fescue (F. idahoensis) and bluebunch wheatgrass (Agropyron spicatum) with scattered ponderosa pine (Pinus ponderosa). Climate is semi-arid with cold winters and hot summers. Mean annual precipitation is 382 mm and mean July maximum and January minimum temperatures were 28.4°C and -6.7°C respectively at Polson (WRCC 2013). Most of the island is natural area in Wildhorse Island State Park. <br>

We collected seeds of Spalding’s catchfly for all experiments from the Dancing Prairie population 160 km north of our study site. Seeds were placed in cold stratification in November, and germinants were obtained in mid-January to mid-February. Germinants were raised in potting soil with native grassland innoculum, first in a greenhouse followed by an outdoor garden. We planted seedlings at 1-meter intervals along four permanent 50-meter transects in an area that currently supports a small population of Spalding’s catchfly. We mapped survivorship in all four transects between mid-June and early July, 2010 through 2013. Prolonged dormancy (see above) made it difficult to unambiguously assign presence or absence of Spalding’s catchfly transplants across all years. Any plant that was present in at least one year between 2010 and 2013 was assumed to be a survivor. Plants observed to be damaged by rodents or ungulates were eliminated from analyses. We used Fisher’s exact test of association (GraphPad Software 2013) to determine whether there was a difference in Spalding’s catchfly survival across treatments. We conducted three experiments begun in three separate years: 2008, 2009, and 2011. <br>

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Reference Code: U14LES01IDUS <br>

Full Citation: Lesica P and T. Divoky. 2014. Augmenting Populations of Spalding’s Catchfly (Silene spaldingii) Populations in Northwest Montana. Ecological Restoration. 32(2): 4 pp. <br>

Location: ELECTRONIC FILE - BOTANY: PLANT SPECIES: {Silene spaldingii} <br>

Keywords: Spalding’s catchfly, Silene spaldingii <br>

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Lesica 2014 Augmenting Silene spaldingii populations.pdf