Changes in light levels and stream temperatures with loss of eastern hemlock (Tsuga canadensis) at a southern Appalachian stream: Implications for brook trout

Siderhurst, Leigh A.; Griscom, Heather P.; Hudy, Mark; Bortolot, Zachary J.

doi:10.1016/j.foreco.2010.08.007

Cited by 35 publications

(22 citation statements)

References 68 publications

(90 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…High overstory mortality levels over similar infestation times have also been observed in New Jersey and Pennsylvania (Mayer et al 2002, Eschtruth et al 2006. Even more rapid deterioration of hemlock has been observed in the southeastern U.S., where hemlock productivity (Nuckolls et al 2009) and crown density (Siderhurst et al 2010) exhibited significant declines and tree mortality increased after only 3-6 years of HWA infestation (Ford et al 2011, Krapfl et al 2011). …”

Section: Factors Controlling Regional Hwa Impactsmentioning

confidence: 72%

A foundation tree at the precipice:Tsuga canadensishealth after the arrival ofAdelges tsugaein central New England

et al. 2012

View full text Add to dashboard Cite

Abstract. Hemlock (Tsuga canadensis) plays a unique role in Eastern forests, producing distinctive biogeochemical, habitat, and microclimatic conditions and yet has begun a potentially irreversible decline due to the invasive hemlock woolly adelgid (Adelges tsugae; HWA) that causes foliar damage, crown loss, and mortality of host trees. Understanding the regional, landscape, site, and stand factors influencing HWA spread and impact is critical for predicting future landscape dynamics and directing effective management. Using aerial photographs, we documented hemlock distribution throughout central Massachusetts and subsampled 123 stands to examine the spatial pattern of HWA and its impact on tree vigor and mortality since its arrival in 1989. In the study region, over 86,000 ha of hemlock forest were mapped in 5,127 stands. White pine (Pinus strobus), red oak (Quercus rubra), red maple (Acer rubrum), and black birch (Betula lenta) were common overstory associates. Hemlock abundance increased from south to north, commonly on western and northwestern slopes. Average stand size was 55 ha, overstory basal area ranged from 23 to 55 m 2 ha À1 and overstory stem densities averaged 993 ha À1 .By 2004, 40% of sampled stands were infested, but most stands remained in good health overall; only 8 stands contained high HWA densities and only two had lost .50% overstory hemlock. Out of fifteen stand and landscape predictor variables examined, only latitude and winter climate variables were related to HWA density. Cold temperatures appear to be slowing the spread and impact of HWA at its northern extent as HWA infestation intensity and hemlock mortality and vigor were significantly correlated with average minimum winter temperature. Contrary to predictions, there was no regional increase in hemlock harvesting. The results suggest that regional HWA-hemlock dynamics are currently being shaped more by climate than by a combination of landscape and social factors. The persistence and migration of HWA continues to pose a significant threat regionally, especially in the northern portion of the study area, where hemlock dominates many forests.

show abstract

Section: Factors Controlling Regional Hwa Impactsmentioning

confidence: 72%

A foundation tree at the precipice:Tsuga canadensishealth after the arrival ofAdelges tsugaein central New England

et al. 2012

View full text Add to dashboard Cite

show abstract

“…Dogwood anthracnose fungus (Discula destructiva) caused major declines in flowering dogwood (Cornus florida) populations-a major contributor to songbird food and calcium cycling (Hiers and Evans 1997). The recent spread of the hemlock wooly adelgid (Adelges tsugae) from New England southward eliminated stands of eastern hemlock (Tsuga canadensis) and Carolina hemlock (Tsuga caroliniana), causing local losses in associated animal species (Tingley et al 2002;Ellison et al 2005), regional homogenization of plant and animal diversity (Ellison et al 2005), changes in soil ecosystem dynamics (Jenkins et al 1999), and altered hydrological regimes (Siderhurst et al 2010). Despite the rapid declines in each of these species, some populations persist through understory sprouting and/ or the maintenance of a low density of resistant individuals (Loo 2008) and at the edges of their ranges.…”

Section: Introductionmentioning

confidence: 99%

Effect of laurel wilt invasion on redbay populations in a maritime forest community

2013

View full text Add to dashboard Cite

“…Evidence suggests that hemlock extirpation from eastern forests would lead to long-term ecological consequences for forest structure and composition (Orwig and Foster 1998;Heard and Valente 2009;Spaulding and Rieske 2010), hydrological processes (Ford and Vose 2007), decomposition rates (Cobb et al 2006;Cobb 2010), and carbon and nitrogen cycling (Jenkins et al 1999;Nuckolls et al 2009;Albani et al 2010;Templer and McCann 2010). Shifts in the community structure and diversity of birds (Tingley et al 2002;Allen et al 2009), fish (Ross et al 2003;Siderhurst et al 2010), amphibians (Brooks 2001), and terrestrial and aquatic arthropods (Snyder et al 2002;Jetton et al 2009;Rohr et al 2009) are also likely. The adelgid also threatens Carolina hemlock (T. caroliniana Engelm.…”

Section: Introductionmentioning

confidence: 99%

Widespread inbreeding and unexpected geographic patterns of genetic variation in eastern hemlock (Tsuga canadensis), an imperiled North American conifer

et al. 2011

View full text Add to dashboard Cite

Eastern hemlock (Tsuga canadensis [L.] Carr.)is an ecologically important tree species experiencing severe mortality across much of its eastern North American distribution, caused by infestation of the exotic hemlock woolly adelgid (Adelges tsugae Annand). To guide gene conservation strategies for this imperiled conifer, we conducted a range-wide genetic variation study for eastern hemlock, amplifying 13 highly polymorphic nuclear microsatellite loci in 1,180 trees across 60 populations. The results demonstrate that eastern hemlock exhibits moderate inbreeding, possibly a signature of a prehistoric decline associated with a widespread insect outbreak. Contrary to expectations, populations in formerly glaciated regions are not less genetically diverse than in the putative southern refugial region. As expected, peripheral disjunct populations are less genetically diverse than main-range populations, but some are highly genetically differentiated or contain unique alleles. Spatially explicit Bayesian clustering analyses suggest that three or four Pleistocene glacial refuges may have existed in the Southeastern United States, with a main postglacial movement into the Northeast and the Great Lakes region. Efforts to conserve eastern hemlock genetic material should emphasize the capture of broad adaptability that occurs across the geographic range of the species, as well as genetic variability within regions with the highest allelic richness and heterozygosity, such as the Southern Appalachians and New England, and within disjunct populations that are genetically distinct. Much genetic variation exists in areas both infested and uninfested by the adelgid.

show abstract

Changes in light levels and stream temperatures with loss of eastern hemlock (Tsuga canadensis) at a southern Appalachian stream: Implications for brook trout

Cited by 35 publications

References 68 publications

A foundation tree at the precipice:Tsuga canadensishealth after the arrival ofAdelges tsugaein central New England

A foundation tree at the precipice:Tsuga canadensishealth after the arrival ofAdelges tsugaein central New England

Effect of laurel wilt invasion on redbay populations in a maritime forest community

Widespread inbreeding and unexpected geographic patterns of genetic variation in eastern hemlock (Tsuga canadensis), an imperiled North American conifer

Contact Info

Product

Resources

About