Predicting xylem phenology in black spruce under climate warming

In the next century, the boreal ecosystems are projected to experience greater rates of warming than most other regions of the world. As the boreal forest constitutes a reservoir of trees of huge ecological importance and only partially known economic potential, any possible climate‐related change in plant growth and dynamics has to be promptly predicted and evaluated. A model for assessing xylem phenology in black spruce [Picea mariana (Mill.) B.S.P.] using daily temperatures and thermal thresholds was defined and applied to predict changes in onset, ending and duration of xylem growth under different warming scenarios with temperatures rising by up to 3 °C. This was achieved by collecting and analyzing a dataset obtained from a 7‐year monitoring of cambium phenology and wood formation on a weekly time‐scale in trees growing in four sites at different latitudes and altitudes in the Saguenay‐Lac‐Saint‐Jean region (Quebec, Canada). The onset of xylem growth occurred between mid‐May and early June while the end ranged between mid‐September and early October, resulting in a growing season of 101–141 days. The model predicted longer duration of xylem growth at higher temperatures, with an increase of 8–11 days/ °C, because of an earlier onset and later ending of growth. With an increase of 3 °C in the mean temperature during the year, the duration of xylem growth changed on average from 125 to 160 days. The predicted changes in cambial phenology could significantly affect future wood production of the boreal ecosystems.     

Private Lands Programs and Lessons Learned in Illinois

ABSTRACT State wildlife agencies commonly offer private landowners cost-share and technical assistance to improve habitat, but the cost-effectiveness and long-term outcomes of these efforts are rarely evaluated. In 1998, we began a 3-part, statewide evaluation of the Illinois Department of Natural Resources’ (IDNR; USA) Private Land Wildlife Habitat Management Program (hereafter the program) as it functioned from 1986 to 1996. We sent a mail-back questionnaire to IDNR biologists to collect information on their perceptions of the program. We sent a separate mail-back questionnaire to private landholders who participated in the program to ascertain their demographic profile, motivations for participation, and attitudes regarding the program. We also conducted on-site evaluations of private properties that were managed under the guidance of the program. We conducted our study to 1) assess if the program effectively assisted participants in establishing and maintaining wildlife habitat, and 2) determine factors associated with optimal management of wildlife habitat on private lands to refine the program and improve effectiveness. We found significant differences between participants in their land use priorities and motivations for managing wildlife and in the resources available to participants to establish and maintain habitat. Our results indicate that although financial incentives may increase participation in private lands initiatives, improving technical and material assistance to landholders is essential for maintaining quality wildlife habitat over the long-term.     

Highly accurate SNP genotyping from historical and low‐quality samples

Historical and other poor‐quality samples are often necessary for population genetics, conservation, and forensics studies. Although there is a long history of using mtDNA from such samples, obtaining and genotyping nuclear loci have been considered difficult and error‐prone at best, and impossible at worst. The primary issues are the amount of nuclear DNA available for genotyping, and the degradation of the DNA into small fragments. Single nucleotide polymorphisms offer potential advantages for assaying nuclear variation in historical and poor‐quality samples, because the amplified fragments can be very small, varying little or not at all in size between alleles, and can be amplified efficiently by polymerase chain reaction (PCR). We present a method for highly multiplexed PCR of SNP loci, followed by dual‐fluorescence genotyping that is very effective for genotyping poor‐quality samples, and can potentially use very little template DNA, regardless of the number of loci to be genotyped. We genotyped 19 SNP loci from DNA extracted from modern and historical bowhead whale tissue, bone and baleen samples. The PCR failure rate was < 1.5%, and the genotyping error rate was 0.1% when DNA samples contained > 10 copies/µL of a 51‐bp nuclear sequence. Among samples with ≤ 10 copies/µL DNA, samples could still be genotyped confidently with appropriate levels of replication from independent multiplex PCRs.     

Initial colonization of periphyton on natural and artificial apices of Myriophyllum heterophyllum Michx

SUMMARY. 1. The initial colonization of periphyton on natural and artificial apices of Myriophyllum heterophyllum Michx was compared at three depths in the littoral zone of Lake Winnipesaukee, a soft-water New England lake. After a 1 week incubation period, the apices were sampled and the periphyton was removed and counted as numbers of periphyton organisms per centimetre of stem.
2. Initial colonization on both substrates was characterized by diatoms, particularly small single-celled species, throughout the spring and summer. Blue-green and green algae occurred in low numbers on both substrates during mid-summer, usually forming a greater percentage of the population of the natural apices. Blooms of the green alga Zygnema sp. dominated both substrates in late August.
3. Community composition generally did not differ significantly by depth or substrate on the natural and artificial apices: however, total abundance was significantly greater on the natural apices. M. heterophyllum appeared to serve as a neutral substrate in terms of community composition but had a positive effect on the total numbers of algae.