 |
 |
 |
|
|
|
|
|
|
 |
 |
 |
 |
 |
 |
 Mississippi |
 Discovered 9-18-2003 by GSRC |
 Mississippi |
 Sweetgum Natural Area March 01, 2004 |
|
Description:
Pondberry is a member of the family Lauraceae. It is one of three members of the genus Lindera found in the southeastern United States, which also includes common spicebush (Lindera benzoin) and bog spicebush (L. subcoriacea). Pondspice (Litsea aestivalis) may be found growing near or in the same habitat as pondberry in the southeastern United States. All four species are deciduous shrubs exhibiting bright red fruits commonly called pondberries. There are seven other genera within the family Lauraceae found in southeastern and southern United States: Persea, Nectandra, Sassafras, Cinnamomum, Licaria, Cassytha, and Litsea (Flora of North America (FNA) 1997). Pondberry was first described in 1788 by Walter as Laurus melissaefolia in Flora Caroliniana from specimens, which he collected within 50 miles of his home in Berkely County, South Carolina. Early authors easily distinguished pondberry from the more prevalent common spicebush. Their descriptions stressed the overall low profile of the plant, shape of the leaves, prominent veination, and pubesescence of the lower leaf surface. However, confusion with pondberry began in 1864 with DeCandolle's Prodromus 15, part 1:244, in which DeCandolle mentioned a reference by Meissner to a collection of pondberry collected by Englemann from Missouri. J.A. Steyermark examined the specimen and found that it was actually a pubescent form of L. benzoin, which was later described by Steyermark and Palmer (1935) as Benzoin aestivale var. pubescens (Lindera benzoin var. pubescens). The discovery of Meissner's mistaken identification led to the discovery that the pubescent form of L. benzoin had frequently and mistakenly been included in L. melissifolia. This resulted in an inaccurately large range for the species that include parts of Illinois and Missouri. In Missouri, pondberry was not discovered until 1948 when Steyermark found it in Ripley County. Steyermark referred to pondberry as potentially being "one of the rarest shrubs in the United States" based on the extremely low numbers of herbarium specimens. He described the species in 1949 and his description remains one of the most detailed accounts of the morphology and taxonomy of pondberry. Pondberry is a deciduous shrub, which grows to approximately 1 to 2 meters in height, reproducing vegetatively by underground stolons, and it has a tendency to form dense thickets. Pondberry leaves are oblong-elliptic to narrowly ovate and drooping. The leaves are 5 to 16 cm in length and 2 to 6 cm in width and tend to be strongly tapered to a point at the apex of the leaf. The under surface of the leaves are strongly net-veined and covered with short, soft pubescence (hairs). When crushed, the leaves emit a strong resemblance of sassafras (Sassafras albidum). In late February to mid-March, prior to the leaves appearing, pondberry produces pale yellow flowers. Pondberry is a dioeceous species meaning males and females are different plants. Both sexes produce the pale yellow flowers which are 5 to 6 mm across and are in tight, stalkless clusters. The petal-like tepals are bright yellow, oblong, and 2 mm in length. The male flowers are in dense clusters, with 9 to 12 stamens surrounded by two whorls of tepals. The female flowers are less conspicuous, with fewer flowers per cluster and a single pistil surrounded by two whorls of tepals, the outer whorl petal-like and the inner whorl reduced to nectar-producing scales. From August to early October, pondberry produces bright red, ellipsoid to oval-shaped fruits approximately 10 to 12 mm in length which mature in the fall. Each fruit or drupe is supported by a stalk from 9 to 12 mm in length by 2.5 to 3 mm thick which appears swollen at its apex.
Habitat:
The habitat requirements of pondberry appear to be highly variable across its range. In the Mississippi alluvial plains of Arkansas, Missouri, and Mississippi, pondberry occurs on sites with perched water tables and vegetation similar to that of bottomland hardwood habitats. In general, it occupies wetland habitats that are normally flooded or saturated during the dormant season, but infrequently flooded during the growing season for extended periods (Tucker 1984). The specific habitat types occupied by pondberry have been variously described, e.g. "mesic to hydric sites (e.g., bottomland hardwood habitats, depressions, and margins of sinks and ponds" (Wofford 1983) and "sandy sinks and pond margins, swamps and pond margins, and swampy depressions (Porcher 1980). Devall et. al. (2000) noted that pondberry has a wide ecological amplitude as long as its requirements for water were met. These habitat types vary from the edges of limestone sinks in South Carolina to depressions within bottomland hardwoods in Mississippi. Although factors such as associate species and soils may vary across its range, the characteristic of occupying locally depressed or ponded areas is consistent throughout its range. However, Gulf South Research Corporation (GSRC) ecologists have observed numerous Delta National Forest pondberry colonies inhabiting ridges in a Ridge-Swale Landscape in many parts of the Forest. The new Delta National Forest colony which was discovered by GSRC on September 19, 2003 was located on a minor slope in an obvious upland community exhibiting no hydrology indicators and approximately 30 feet from an adjacent palustrine forested wetland. Other colonies in the Delta National Forest have been observed by GSRC on ridges higher than the surrounding landscape. These ridges range from approximately 1 foot to approximately 3 feet above the nearby wetland swales indicating a mesic community type.
Range:
Pondberry is presently found in the Mississippi River alluvial plains of Missouri, Arkansas, Alabama, and Mississippi, and the Coastal Plains region of Georgia, South Carolina, and North Carolina (USFWS 1993; Tucker 1984; ALNHP 2004). Pondberry is believed to be extirpated from Florida and Louisiana in its historic nine-state range. Although a few extant populations appear quite large, many of the plants may be clones rather than different genetic individuals (NatureServe Explorer 2002). In Florida, pondberry was last observed inhabiting limestone sinks and poorly drained depressions in Gadsden County (Coile 2000). In Louisiana, the last known occurrence of pondberry was described as inhabiting the "Low Banks of Ouachita River near Arkansas line" and was described by Carpenter (Thomas, D. R. and C. M. Allen 1998). Surveys were conducted for pondberry in northeastern Louisiana at Tensas River National Wildlife Refuge (NWR) during the months of March and April 2003 by Gulf Coast Biological Surveys, Inc. under contract from the Louisiana Natural Heritage Program. Priority search areas included the margins of small natural lakes and ponded depressions followed by semi-permanently flooded hardwood sloughs. The third priority search area included better drained ridges where palmetto was infrequent or absent. Much of Tensas River NWR was not covered during the survey. Large portions of the Refuge presently contain suitable pondberry habitat. However, Leonard reports that pondberry cannot be ruled out as not occurring on the NWR (Leonard 2003). In August 2004, Al Schotz of the Alabama Natural Heritage Program discovered two (2) colonies of pondberry in Covington County, Alabama (ALNHP 2004). Prior to this exciting 2004 re-discovery, pondberry was last observed in Wilcox County in 1840, described as "inhabiting low thickets in seasonally flooded wetlands" (ALNHP, 2003). The extensive clearing and drainage of bottomland forests throughout the Southeast has probably been the major factor affecting the species. Threats to its habitat remain high in most of the range, but some pondberry sites in South Carolina, Mississippi and Missouri are protected (NatureServe 2003). Approximately 273 colonies/populations of pondberry are currently known to exist across its current 7-state range (including the new August 2004 Alabama pondberry colony). Approximately 204 colonies can be found in Mississippi, primarily in the Delta National Forest (192 colonies in the Delta National Forest and 12 colonies on private lands approximately 65 miles north of the Forest); 2 colonies in Alabama (private lands); 36 colonies in Arkansas; 9 populations in Georgia (includes new March 2004 & 2005 colonies); 15 colonies in South Carolina; 2 populations in North Carolina; and 5 colonies composing 1 natural population in Missouri (ALNHP 2004; NCNHP 2003; SCNHT 2003; GNHP 2003; ARNHP 2003; MONHP 2003; GSRC 2001 and 2003). In Missouri, restoration efforts have been conducted since the early 1990’s to establish new pondberry colonies by direct seeding and establishment of greenhouse cultivated seedlings at Corkwood Conservation Area and Sand Pond Conservation Area in Ripley County, Missouri. These populations are not included in the total number of populations listed above for Missouri.
Special Identification Features:
Pondberry may be confused with common common spicebush (Lindera benzoin and pondspice (Litsea aestivalis). Pondberry can be distinguished by these species by pondberry's drooping, thin, membranaceous, and ovately to elliptically shaped leaves which have a strong, sassafras-like odor when crushed. Pondberry is colonial species, producing cane-like clusters of short-lived stems, has large (over 5 cm long, over 1.5 cm wide) leaves, and bears ellipsoid fruits, 10 to 12 mm in length. In contrast, pondspice ranges from a bushy shrub to a small tree which may either form thickets or occur singly, has minute leaves less than 3 cm in length and less than 1 cm in width, as well as oblong leaves and globose fruits, which are 4 to 6 mm in diameter. Common spicebush is a taller, more upright shrub with leaves generally widest above the middle (obovate) and, when crushed, emitting a strong, lemony aroma.
Background
Pondberry is currently listed as a Federally endangered species under the Endangered Species Act of 1973. Pondberry was officially listed on 31 July 1986 in the Federal Register (51(47):27495-27500). A Final Recovery Plan was completed by the USFWS in September of 1993. No critical habitat has been proposed for pondberry. A population has been defined as "one or more colonies that are in close enough proximity to regularly interbreed and separated from other populations by a sufficient distance to preclude interbreeding on a regular basis" (USFWS 1993).
Population Biology
Pondberry populations are generally associated with the shade of a mature forest and may be shade dependent (Klomps 1980a and Tucker 1984). Pondberry has been reported to be stunted when growing if full sun (USACE 1996); however, Devall et. al. (2000) reported that one population near McRae, Georgia is thriving despite the plants growing in a very open area and receiving practically full sun. Field investigations have indicated that vigorous healthy colonies were found in homogeneous clumps with shrub associates growing adjacent to but not within the clumps. In less vigorous colonies, shrub/vine associates were usually growing within the clumps. Individual stems within each colony are short-lived, generally dying by their seventh or eighth year. Young stems sprout from the rootstock and replace the dying stems. Over time, colonies may expand vegetatively resulting in many vastly rooted stems. A typical vigorous colony, thus, is composed of numerous relatively tall stems, dead and dying stems, as well as young leaf sprouts. There is little record of new seedling establishment and growth; therefore, colony expansion is suspected to be purely vegetative (Tucker 1984; USFWS 1990).
Reproductive Biology & Studies
Individual stems of pondberry begin flowering by their third year of growth (Tucker 1984). Flowering begins in late February to early March in Mississippi and generally lasts no longer than two weeks. Pondberry is a dioecious species (male and female flowers on separate plants). A typical colony in Mississippi is composed primarily of male stems with a few to several female stems. In some instances, the entire colony is composed of male plants. In general, seed production in relation to the total number of stems is low. Because flowering occurs in late February to early March, frost or near freezing temperatures often damage flowers, thereby reducing fruit production even more. Rayner and Ferral (1988), in a study of 73 colonies from the Honey Hill region of South Carolina, reported that only 22 percent of all colonies surveyed produced fruit, with fruit production averaging only 22 fruits per colony. They also noted that fruit production did not seem to improve with plant health since sexual reproduction appeared to be poor even in large, healthy plants. Few details are known about pondberry's reproduction. Pondberry is suspected to be insect pollinated. Tucker (1984) noted small bees and flies on flowers when observing plants in Arkansas. The fruit contains many oils and similar compounds, which are suspected to make the fruit unpalatable to most wildlife. Therefore, seed dispersal is likely accomplished by seeds merely falling to the ground or by animals picking the fruit and depositing elsewhere (USFWS 1990). Extremely rare occurrences of seedlings have been documented in the wild. Seed germination beneath parent plants was reported as being successful if the seeds were depressed beneath the soil surface (USFWS 1993; Wright 1989). In addition, cleaned and stratified seeds have been reportedly germinated by McCartney (in litt.) as reported by the USFWS (1993). No hybrids are currently known to occur with pondberry. A 1939 observation of the pondberry site in Bladen County, North Carolina indicated there was no evidence that the plants were reseeding themselves, although fruits were observed on the plants during the field investigation (NCNHP 2003). A field investigation conducted in 1995 and 1994 at the Cumberland and Sampson Counties, North Carolina populations found that "plants which bore fruit in 1994 were sterile in 1995, and plants that were sterile in 1994 bore fruit in 1995; plants were in full flower on 26 February 1995; on 31 October 1994 fruits had not dropped nor had they been significantly eaten by birds or other wildlife" (Leonard 2003 and NCNHP 2003). Leonard, 2003 also determined that the majority of the pondberry plants at the North Carolina sites are primarily female, rather than male, which other researchers have suggested. Leonard has conducted reproductive studies of pondberry fruits collected from the wild from naturally occurring colonies. In his studies, he found that germination occurred in the months of March and April with a 70 to 95 percent germination rate with seeds planted "in a good garden potting mix". He also noted that the fruits of pondberry do not float after dropping from the adult plants in the fall. In germination studies, Leonard (2003) found that plants he transplanted from pots to sites containing red, clay soil of the Piedmont of central North Carolina survived in full sun without ever being flooded. In a period of two to three years, the pondberry stems experienced die-back. Leonard reported that the transplanted pondberry plants have survived for 12 years in non-flooded, upland soils. In October 1990, one year old, greenhouse cultivated pondberry plants were transplanted to permanent plots at the Corkwood Conservation Area in Ripley County, Missouri. The plants were cultivated from seeds collected in the fall of 1989 from the nearby naturally occurring plants at the Sand Pond Conservation Area. Prior to planting, the pericarp of each fruit was removed and the seeds were stratified. The greenhouse seedlings were planted at two sites on the Conservation Area approximately 0.8 km apart in low swale communities, which seasonally hold water, located under a closed tree canopy. The plots were monitored yearly from 1992 through 2000 during either the months of August or September, excluding the year 1999. Collected data included survival statistics and height of the tallest plant at each plot. Monitoring revealed that surviving pondberry plants suffered die-back, but re-sprouted. Some specimens produced numerous stems when the plant had only one stem prior to die-back the previous year. The study results concluded that one hundred fifty-six (156) plants were established in 1990 and only 11 pondberry plants had survived to the fall of 2000 accounting for a 7.1 percent survival rate. Of the total surviving plants, some plants had produced rhizomes and five original plants had produced multiple stems (Smith 2003). In 1993, pondberry seeds were planted directly in to the soil in either 1 meter by 1 meter permanent plots or along 30 meter transects near the seedling transplant plots at the Corkwood Conservation Area. Twenty-five seeds were planted in each of the 1 meter by 1 meter plots. Fifty-nine seeds were planted at 0.5 meter intervals, along two transects. In addition, two transects were planted with 329 seeds total near the naturally occurring pondberry plants at the Sand Pond Conservation Area in a transition area ranging from full sun to shade. The later two transects were planted using a spacing pattern of 50 cm or 10 cm between seeds. The seeds used for direct seeding at both Conservation Areas originated from red or orange fruit collected from naturally occurring pondberry plants at the Sand Ponds Natural Area. The pericarps of the fruit were removed and the seeds were washed in water. The seeds were planted at each site within one day of collection from the parent plants. The pondberry seeds were planted below the surface of the leaf litter to a depth from 1 to 3 cm. Transects were monitored yearly from 1994 through 2000 during either the months of August or September, excluding the year 1999 (Smith 2003). The analysis of the seed planting results was based only from transects at the Corkwood Conservation Area in which 50 cm seed spacing was used and the Corkwood plots in which seeds were planted 20 cm apart. From these sites, 9.33 percent of the planted seeds germinated to form seedlings one year after planting. In successive years additional seeds germinated bring the 9.33 percent total to 44.2 percent germination rate. During the following 3 years of monitoring, cumulative germination continued to increase at a slower pace and reached 53.6 percent by the seventh year after planting. The mean height of the first year seedlings on Corkwood transects was 8.44 cm. The tallest seedling was a 4-year plant at 22.9 cm. Two years later when measured again, the plant was found to be at the same height of 22.9 cm (Smith 2003). Colonel Richard Porcher transplanted pondberry plants into the Cainhoy Lindera Transplant Complex on the Francis Marion National Forests, which was supported by the USFWS. Two years after transplanting, the pondberry plants were determined to be surviving and appeared to be robust. In January 1995, Porcher's ecology class from The Citadel in Charleston, South Carolina transplanted 75 rhizomes into the site as a class exercise to monitor the survivability of transplanted pondberry colonies (Porcher 1995). In September 1992, a population of pondberry was transplanted into the Hoover Road Pond Cypress Savannah near French Quarter Creek on the Francis Marion National Forest as part of a study between the USFS and the USFWS. In the spring of 1994 the transplanted pondberries were checked and found to be surviving and established. The plants were described as being robust (Porcher 1995). Devall et. al. (2003) investigated establishing new pondberry populations in Mississippi as an aid in conserving the species. Young pondberry stems were collected from a naturally occurring population, planted in pots, and grown for several weeks in a greenhouse. The pondberry stems were then transplanted to five protected locations in the in Mississippi. Each pair of male and female plants was surrounded by a wire cage on wooden supports, and was labeled. The transplanted pondberry stems were watered during dry period, monitored for growth and disease, and pesticides and fertilizers were applied as needed. After two years or monitoring and care, the survival of the plants found to be good. However, one site, the plants became infested with scale. Many of the plants had stems that increased in height, although the height of the tallest stems decreased. Many of the pondberries produced new stems, but some older stems died during the year.
Threats and Reasons for Species Decline
Several authors have discussed the reasons behind the suspected decline of pondberry throughout its range. There are no literature records of pondberry’s historic abundance. However, apparent reasons for pondberry’s current endangered status have been documented, as discussed in the following paragraphs.
Alteration and Habitat Loss
The most critical threat to pondberry, as with many endangered species, is the alteration/modification and/or loss of habitat. Three factors, which constitute this threat, are certain timber harvesting practices, certain drainage activities, and land clearing operations for agricultural, commercial, and private development (USFWS 1990). Various problems are associated with timber-harvesting activities such as heavy equipment crushing plants, felled trees crushing plants or uprooting adjacent trees, opening closed or dense forest canopies, and possible changes in local hydrology. Kral (1983) reported that single-tree selection harvesting in hardwoods would likely not affect pondberry, while clear-cut harvesting, which would result in increased surface water runoff, could potentially increase flood water levels to a detrimental degree. Within the Delta National Forest in Mississippi, the U.S. Forest Service, along with the USFWS, determined that a 100-foot undisturbed buffer around known pondberry colonies along with a 40-acre size limit on clearcut openings would prevent any major changes in hydrology and maintains an adequate crown closure around a colony (Baker and Goetz 1989). Several authors have made general statements about drainage activities and subsequent effects on pondberry such as ditching which could reduce the surface and/or groundwater regime in a manner that could reduces the plant’s vigor or possibly eliminate it from an existing site (USFWS, 1993). The USACE (1991b) through extensive field studies of pondberry within Mississippi and consultation with various experts, determined that activities, which significantly alter the local hydrological regime of depressions, ponds, sink, or other areas governed by localized hydrology would adversely affect pondberry colonies. The third factor associated with the loss of habitat is land clearing due to agricultural interests and other developments. Throughout pondberry’s range, bottomland hardwoods and similar habitats have been extensively cleared. Within the Mississippi River alluvial valley, bottomland hardwoods decreased 56 percent from 11.8 million acres in 1937 to 5.2 million acres in 1978 while agricultural/croplands increased nearly five million acres during the same time period (USFWS 1979). Habitat loss alone appears to be a major factor in the current endangered status of pondberry.
Disease and Predation
The literature indicates that nearly all colonies of pondberry are affected by stem dieback. Rayner and Ferral (1988) reported that stem dieback and predation were two factors that lead to poor colony health in the Honey Hill region of South Carolina. Stem dieback has been hypothesized to be fungal and/or drought related but could be characteristic of the species. Predation has been observed by deer and insects, mainly the spicebush swallowtail caterpillar (Rayner and Ferral 1988; USACE 1991a). Devall et. al. (2000) found six insect species in association with pondberry, but none of them appear to be a limiting factor for the plant. Through field studies of pondberry colonies in Mississippi, stem dieback and insect damage seems to influence the general health of many colonies (USACE 1991a). McDearman (unpublished data, U.S. Fish and Wildlife Service, e.g. USACE 1996) monitored substantial dieback and plant mortality during 1991-1993 at a study site in DNF. Devall et al. (2000) reported dieback of 33 percent of the stems during June at a site in Shelby County, Mississippi. The best available information seems to indicated that stem dieback is related to fungal pathogens, drought, and the interactions between pathogens and drought. In addition, Devall et. al. (2000) noted that in unusual conditions stem dieback may be caused by winter freezing. McDearman (1993) reported that within certain morphological constraints, stem dieback on pondberry can be a natural process of senescence. Subsequent monitoring and studies of plant growth and decline (unpublished, U.S. Fish and Wildlife Service, e.g. USFWS 2000a) at colonies in DNF found that most instances of stem dieback were accompanied by abnormal patterns of sudden leaf wilt and death during the growing season on plants of all size-classes. This pattern was not indicative of senescence and dieback of old or large plants. Dead stems have been reported at various locations in different pondberry locations, Wright (1989a) first reported leaf senescence, summer leaf fall (facultatively deciduous), and twig dieback on pondberry plants in response to summer drought conditions in Arkansas. In DNF, the pathological symptoms of active dieback were directly observed and monitored by McDearman at 10 pondberry colonies (USFWS 2000b). The first symptoms were characterized by rapid leaf-wilt and sudden death of leaves and stems, during a late summer dry period, without leaf abscission. Stem, branch (more than one stem), or whole plant death followed during the subsequent fall and winter. Since leaves died rapidly in the summer without abscission at the DNF sites, additional investigations by Dr. Douglass Boyette (USDA Agricultural Research Service) revealed several potential pathogens, including Diaporthe sp., the cause of stem-canker. Browsing by vertebrates appears to occur only occasionally. Some stems were reported to be eaten by rabbits during the winter (Wright 1989). The USACE (1991a) reported evidence of herbivory at only one of 44 pondberry colonies in the Delta National Forest.
Lack of Reproduction
Recent accounts and studies of pondberry list poor sexual reproductive success as another important reason in the decline of pondberry colonies. Many of the colonies studied in Mississippi consisted mainly of male plants and some entire colonies contained only male stems. Consequently, colony expansion is suspected to occur primarily vegetatively. Sexual reproduction can be accomplished in a controlled environment (such as a nursery) as reported by the USFWS (1990), which indicated successful seed germination when seeds were depressed below the soil surface. During field surveys of the Mississippi population on the DNF, numerous apparently viable seeds were observed on plants although no germination from the previous year’s fruits was observed. With the abundance of suitable habitat within DNF, it is likely that if germination and sexual reproduction can occur in the wild, it could be occurring there. Leonard (1995) reported inundation tolerance of pondberry seedlings may be a strongly limiting factor. In North Carolina populations, he observed that seedlings with developed leaves showed no obvious signs of deleterious effects from flooding during the month of June, however emerging seedlings may not survive after several days of flooding. Reports by Tucker (1984) and Morgan (1983) indicated that germination and new seedling establishment may not occur in the wild. Therefore, maintenance and increases of extant populations without man’s intervention may depend on expansion of established clones. However, long term monitoring of known colonies and adjacent areas is needed to determine if new seedling establishment occurs.
Other Reasons For Decline
In the Francis Marion National Forest in South Carolina, monitoring conducted in from 1995 to 1998 indicated the majority of the ten populations of pondberry on the Forest are stable. However, research indicated that the two populations at the Honey Hill Limesink area are declining for unknown reasons (USFS 2000). Monitoring for pondberry in the Honey Hill Limesink area, Raynor and Ferrel documented the status of each pondberry colony. Recorded data included size, vigor, area, and reproduction of pondberry as well as associate plant species. Raynor and Ferrel also looked for evidence of predation or diseases and light and moisture environment. Of the large number of colonies found, they discovered that nearly half of all of the colonies (44.6 percent) were of low vigor. Low vigor was defined as possessing stems 6 to 18 inches in height with no evidence of reproduction. Only 22 percent of the overall colonies at the Honey Hill Limesink area had produced fruit. Raynor and Ferrel attributed the poor condition of pondberry to be related to stem-die back, predation (either white-tailed deer (Odocoileus virginianus) or insects), and potentially drought (Roecker 1998). In 1996, the USFS conducted prescribed burns and at the Complex as well as removing a percentage of the site’s mid-story near a percentage of the pondberry colonies. The USFS observed little favorable responses in the pondberry colonies (USFS 2000). Other potential reasons for decline such as grazing and trampling by cattle and hogs, changes in climatic conditions, and sever winter stress have been noted in Missouri and Arkansas populations (Federal Register 51(147):27495-27500; USFWS 1990). Sites in both Georgia and Arkansas are being adversely impacted due to trampling by domestic livestock (cattle and hogs) in nearby pastures. In addition, a weevil (Heilipus squammosus) has been found to be associated with the dying twigs on pondberry, which may have some effect on pondberry (USFWS 1993). Devall et. al. (2000) found that this weevil may provide for an opening for disease, but due to the rarity of this weevil and the common occurrence of dying twigs of pondberry, H. squammosus probably does not play a significant role. Further evaluation is required to fully understand the relationship.
References
|
