Distinct Climate Effects on Dahurian Larch Growth at an Asian Temperate-Boreal Forest Ecotone and Nearby Boreal Sites

Climate change is exerting profound impacts on the structure and function of global boreal forest. Compared with their northern counterparts, trees growing at the southern boreal forest and the temperate-boreal forest ecotone likely show distinct responses to climate change. Based on annual basal areal increment (BAI) of Dahurian larch (Larix gmelinii Rupr.) plantations with similar ages, tree densities and soil nutrient conditions, we investigated the tree growth responses to inter-annual climate variations at an Asian temperate-boreal forest ecotone and nearby boreal sites in northeast China. Annual BAI changed nonlinearly with cambial age in the form of a lognormal curve. The maximum annual BAI showed no significant difference between the two bioregions, while annual BAI peaked at an elder age at the boreal-temperate forest ecotone. After eliminating the age associated trend, conditional regression analyses indicate that residual BAI at the boreal sites increased significantly with higher growing-season mean nighttime minimum temperature and non-growing-season precipitation, but decreased significantly with higher growing-season mean daytime maximum temperature during the past three decades (1985–2015). In contrast, residual BAI at the boreal-temperate forest ecotone only showed a positive and weak response to inter-annual variations of growing-season precipitation. These findings suggest distinct effects of inter-annual climate variation on the growth of boreal trees at the temperate-boreal forest ecotone in comparison to the southern boreal regions, and highlight future efforts to elucidate the key factors that regulate the growth ofthe southernmost boreal trees.

Mitigation Potential of Ecosystem-Based Forest Management under Climate Change: A Case Study in the Boreal-Temperate Forest Ecotone

The forest sector can help reduce atmospheric CO2 through carbon (C) sequestration and storage and wood substitution of more polluting materials. However, climate change can have an impact on the C fluxes we are trying to leverage through forestry. We calculated the difference in CO2 eq. fluxes between ecosystem-based forest management and total forest conservation in the context of the temperate-boreal forest ecotone of Quebec (Canada), taking into account fluxes from forest ecosystems, wood product life cycle, and the substitution effect of wood products on markets. Over the 2020–2120 period, in the absence of climate change, ecosystem-based forest management and wood production caused average net annual emissions of 66.9 kilotonnes (kt) of CO2 eq. year−1 (relative to forest conservation), and 15.4 kt of CO2 eq. year−1 when assuming a 100% substitution effect of wood products. While management increased the ecosystem C sink, emissions from degradation of largely short-lived wood products caused the system to be a net source. Moreover, climate warming would decrease the capacity of ecosystems to sequester C and cause a shift towards more hardwood species. Our study highlights the need to adapt the industrial network towards an increased capacity of processing hardwoods into long-lived products and/or products with high substitution potential.

Changes in the prairie–forest ecotone in northwest Ontario (Canada) across the Holocene

Pollen and diatom assemblages from well-dated sediment cores from three lakes forming a west-to-east transect across the boreal forest in northwest Ontario (Canada) were used to evaluate the timing and nature of the movement of the prairie–forest ecotone (PFE) across the Holocene. Changes in vegetation, temperature, and effective moisture were inferred from pollen and pollen-based transfer functions. Analyses indicated site-specific vegetational and climate changes across short spatial distances, with prolonged prairie-like conditions during the middle Holocene at the westernmost site. Increased reconstructed temperatures at this westernmost site occurred from ~9000 to 3000 cal yr BP, alongside increases in diatom-inferred lake levels beginning at ~6000 cal yr BP. The abundance of Quercus peaked concurrently with rising lake levels before declining to trace levels by ~3000 cal yr BP. Increases in the abundance of non-arboreal pollen between ~8500 and ~4500 cal yr BP at the more eastern lakes suggest relatively delayed and truncated PFE influence, before the reestablishment of primarily boreal taxa by ~4500 cal yr BP, coincident with diatom-inferred increases in lake levels. This study shows that the PFE moved both farther east and north than previously determined, but generally agrees with established patterns in vegetation from other studied regions along the PFE.

Checklist of butterflies (Lepidoptera: Papilionoidea) of an urban area of Caatinga-Atlantic Forest ecotone in Bahia, Brazil

The butterfly inventories carried out in urban landscapes in Bahia are still scarce. Urban areas with remnants of native vegetation in association with ornamental plants can provide several resources that are favorable for the development and shelter of various animal species, including insects, even with the high anthropization that occurs in these environments. In this work, we aim to investigate the urban fauna of butterflies at the Campus of the Universidade Estadual de Feira de Santana (UEFS), an area of ​​Caatinga-Atlantic Forest ecotone located in the municipality of Feira de Santana, Bahia, Brazil. Monthly samplings were carried out with entomological net and standardized traps with different attractive baits, between May 2019 and January 2020, in addition to review of the material previously deposited at the Entomological Collection Prof. Johan Becker located at the Zoology Museum of the UEFS (MZFS). In total, 114 species of Papilionoidea were recorded, with Nymphalidae being the richest family (45 species), followed by Hesperiidae (32), Lycaenidae (21), Pieridae (10), Papilionidae (3) and Riodinidae (3). Thirteen species are new records for Bahia and eight species are new records for Northeast Brazil. The results demonstrate the extreme relevance of the conservation and preservation of urban green areas for the maintenance of butterflies species and, consequently, the associated insect fauna.

First record of Strix huhula Daudin, 1800 (Strigiformes, Strigidae), Black-banded Owl, from the savanna–dry forest ecotone in northeastern Brazil

Strix huhula Daudin, 1800 is widely distributed species of owl in the Neotropical region. However, this species is considered rare in nature due to its dependence on forested habitat and low adaptive capacity to survive in anthropogenic environments. There are scattered records throughout Brazil. Here, we provide the first record of S. huhula in a savanna–dry forest ecotone in Piauí state. This expands the geographic distribution of S. huhula to northeastern Brazil.