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"Rainforest"
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In the valleys of the noble beyond : in search of the Sasquatch
On the central coast of British Columbia, the Great Bear Rainforest is part of the largest temperate rainforest in the world; for centuries people have reported encounters with the Sasquatch.
Book
Insights into Landscape Structure Change in Urbanising Rainforest and Guinea Savanna Ecological Regions of Nigeria
In the face of unabated urban expansion, understanding the intrinsic characteristics of landscape structure is pertinent to preserving ecological diversity and managing the supply of ecosystem services. This study integrates machine-learning-based geospatial and landscape ecological techniques to assess the dynamics of landscape structure in cities of the rainforest (Akure and Owerri) and Guinea savanna (Makurdi and Minna) ecological regions of Nigeria between 1986 and 2022. Supervised classification using the random forest (RF) machine-learning classifier was performed on Landsat images on the Google Earth Engine (GEE) platform, and landscape metrics were calculated with FRAGSTATS to assess landscape composition, configuration, and connectivity. The results reveal a consistent pattern of urban expansion in all four cities at varying intensities. The proportion of the built-up class exhibited positive correlations with the largest patch index (r = 0.86,
p
< 0.05) and aggregation (r = 0.39,
p
< 0.05), indicating a concurrent rise in landscape densification as urban expansion persists. For the agricultural and vegetation landscapes, landscape proportion correlates negatively with fragmentation (
r
= −0.88,
p
< 0.05) and connectivity (
r
= −0.77,
p
< 0.05), but positively with aggregation (
r
= 0.89,
p
< 0.05). The increased patch density indicates a rising magnitude of landscape fragmentation and heterogeneity over time with varying implications for ecosystem functioning. These findings demonstrate the complex interplay between urbanisation and ecological processes within and across different ecoregions, highlighting the need for targeted ecological management, sustainable urban planning, and regionally informed landscape conservation strategies.
Journal Article
Fossil evidence for Cretaceous escalation in angiosperm leaf vein evolution
The flowering plants that dominate modern vegetation possess leaf gas exchange potentials that far exceed those of all other living or extinct plants. The great divide in maximal ability to exchange COâ for water between leaves of nonangiosperms and angiosperms forms the mechanistic foundation for speculation about how angiosperms drove sweeping ecological and biogeochemical change during the Cretaceous. However, there is no empirical evidence that angiosperms evolved highly photosynthetically active leaves during the Cretaceous. Using vein density (DV) measurements of fossil angiosperm leaves, we show that the leaf hydraulic capacities of angiosperms escalated several-fold during the Cretaceous. During the first 30 million years of angiosperm leaf evolution, angiosperm leaves exhibited uniformly low vein DV that overlapped the DV range of dominant Early Cretaceous ferns and gymnosperms. Fossil angiosperm vein densities reveal a subsequent biphasic increase in DV. During the first mid-Cretaceous surge, angiosperm DV first surpassed the upper bound of DV limits for nonangiosperms. However, the upper limits of DV typical of modern megathermal rainforest trees first appear during a second wave of increased DV during the Cretaceous-Tertiary transition. Thus, our findings provide fossil evidence for the hypothesis that significant ecosystem change brought about by angiosperms lagged behind the Early Cretaceous taxonomic diversification of angiosperms.
Journal Article
A bear's life
\"This nonfiction picture book is full of ... wildlife photographs of the bears of the Great Bear Rainforest in British Columbia\"-- Provided by publisher.
Book
Past and present genetic structure of the tropical rainforest palm Astrocaryum mexicanum : effects of anthropogenic fragmentation
To assess whether fragmentation of the lowland rainforest of Los Tuxtlas natural reserve has altered the genetic structure of understory palm Astrocaryum mexicanum , we analyzed populations from undisturbed forest and forest fragments. The questions that this study addressed were: Has habitat fragmentation reduced gene flow and within-population genetic variation (allele loss)? Has this process, in turn, increased population genetic differentiation of populations in fragments? We expected that reduced population sizes and gene flow, in fragments, has increased the effects of genetic drift, thus affecting genetic structure. The design of the study allows control for pre-fragmentation genetic structure, a common criticism against fragmentation studies, and addresses this question for a community-level important palm tree species of the tropical rain forests of southern Mexico. We sampled two cohorts ( i.e. , pre- and post-fragmentation palms) in each of eight populations (thirty individuals per cohort or generation, and a separation of four to nine km between populations), one composed by adult palms (80–140 years old), and the other of seedlings <3 years old. We estimated R ST , inbreeding coefficient, number of alleles, heterozygosity, linkage disequilibrium, and number of migrants per generation, using variation at eight novel microsatellite loci, developed ex profeso for this study. Results indicate lack of differentiation between population pairs, and most genetic variation exists within subpopulations, implying high historical connectivity. Fragments were not genetically distinct from continuous forest populations. Simulations suggest a severe effective population size reduction at the outset of the Last Glacial Maximum 26,000 YBP, after which the area was recolonized by individuals from Central America. It is possible that the number of reproductive events that have passed since the onset of fragmentation has been insufficient to detect an effect on genetic variation, or that the extant number of palm trees in fragments is high enough to maintain the genetic diversity; bottleneck simulations agree with the first explanation. Notwithstanding, evidence suggests that populations in fragments face harsher environmental conditions, selecting against homozygotes, a situation that can jeopardize their persistence in fragments if population size is too small.
Journal Article
The oil man and the sea : navigating the Northern Gateway
Kopecky relates his travels through the Great Bear Rainforest and into the controversy surrounding the building of the Northern Gateway pipeline.
Book
Forest system hydraulic conductance
• Soil–leaf hydraulic conductance determines canopy–atmosphere coupling in vegetation models, but it is typically derived from ex-situ measurements of stem segments and soil samples. Using a novel approach, we derive robust in-situ estimates for whole-tree conductance (k
tree), ‘functional’ soil conductance (k
soil), and ‘system’ conductance (k
system, water table to canopy), at two climatically different tropical rainforest sites.
• Hydraulic ‘functional rooting depth’, determined for each tree using profiles of soil water potential (Ψsoil) and sap flux data, enabled a robust determination of k
tree and k
soil. k
tree was compared across species, size classes, seasons, height above nearest drainage (HAND), two field sites, and to alternative representations of k
tree; k
soil was analysed with respect to variations in site, season and HAND.
• k
tree was lower and changed seasonally at the site with higher vapour pressure deficit (VPD) and rainfall; k
tree differed little across species but scaled with tree circumference; r
soil (1/k
soil) ranged from 0 in the wet season to 10× less than r
tree (1/k
tree) in the dry season.
• VPD and not rainfall may influence plot-level k; leaf water potentials and sap flux can be used to determine k
tree, k
soil and k
system; Ψsoil profiles can provide mechanistic insights into ecosystem-level water fluxes.
Journal Article
Wolf Island
This nonfiction picture book illustrated with wildlife photographs and tells the story of a lone wolf who swims to an island in the Great Bear Rainforest.
Book
Depth of soil water uptake by tropical rainforest trees during dry periods: does tree dimension matter?
Though the root biomass of tropical rainforest trees is concentrated in the upper soil layers, soil water uptake by deep roots has been shown to contribute to tree transpiration. A precise evaluation of the relationship between tree dimensions and depth of water uptake would be useful in tree-based modelling approaches designed to anticipate the response of tropical rainforest ecosystems to future changes in environmental conditions. We used an innovative dual-isotope labelling approach (deuterium in surface soil and oxygen at 120-cm depth) coupled with a modelling approach to investigate the role of tree dimensions in soil water uptake in a tropical rainforest exposed to seasonal drought. We studied 65 trees of varying diameter and height and with a wide range of predawn leaf water potential (Ψ pd ) values. We confirmed that about half of the studied trees relied on soil water below 100-cm depth during dry periods. Ψ pd was negatively correlated with depth of water extraction and can be taken as a rough proxy of this depth. Some trees showed considerable plasticity in their depth of water uptake, exhibiting an efficient adaptive strategy for water and nutrient resource acquisition. We did not find a strong relationship between tree dimensions and depth of water uptake. While tall trees preferentially extract water from layers below 100-cm depth, shorter trees show broad variations in mean depth of water uptake. This precludes the use of tree dimensions to parameterize functional models.
Journal Article