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Forest tree species strongly influence forest dynamics and management. French forests have the greatest compositional diversity in Europe, which constrains the quantitative analysis of associated wood resources. A partition of French forests according to dominant tree species composition and stratified by biogeographical regions (GRECO) was developed in order to handle this diversity. The partition relies on forest composition as measured by the national forest inventory (2006–2015, > 65,000 plots). It builds on the J-shaped distribution of elementary composition abundance, identifies dominant compositions describing at least 50% of the GRECO's area, and groups minor compositions. An ecological assessment of this partition and its application to the analysis of the growing stock are developed. The partition describes 61.4% of the forest area (66% of the growing stock) according to 29 dominant compositions, demonstrating its efficiency. These compositions revealed the importance of broadleaved mixtures, and of neglected forest strata (pine species in Northern France). Growing stock density appeared lowest in broadleaved compositions (Mediterranean oaks), and highest in some coniferous compositions (silver fir/ Norway spruce mixture in mountains). Partitioning highlights the role of ecological contexts and forest management on tree diversity.
In Canada, boreal open woodlands (OWs) show interesting afforestation potential, but no detailed study is available regarding the carbon fraction (CF) of dry matter in biomass and litter reservoirs (tonne C/tonne dry mass). This study aimed at providing the very first specific CF values of C reservoirs and compartments in OWs, with the main hypothesis that given the particular stand characteristics of OWs, more precise CF values than IPCC's default values would significantly change the calculation of C stocks in OWs. Results indicate that even though the CF values measured in this study were significantly different among the different C reservoirs and compartments in OWs, they matched the IPCC default CF values for the biomass (0.50) and humus (0.37) reservoirs. Therefore, the main hypothesis of this study – that more precise CF values than IPCC's default values would significantly change the calculation of C stocks in OWs – was not supported by the results. Consequently, the IPCC default values of the CF in the biomass and litter (humus) reservoirs can be used to estimate C stocks in boreal OWs, for example when using OWs as the baseline scenario in afforestation projects.
Management planning for Canadian species at risk of extinction begins with recommendation for legal protection under the Species at Risk Act (SARA), and ends with Action Plans that guide management implementation. Roughly five years after the enactment of SARA in 2002, multiple studies identified taxonomic biases associated with the SARA listing process. Here, we provide a comprehensive test of whether taxonomic biases remain over a decade later. We also test whether biases in listing are propagated through to management implementation. We find that birds, reptiles and plants are more likely to be legally protected than other species. Arthropods and fishes are less likely to be protected, with unlisted fish species being twice as likely to be threatened by resource use than other unlisted species. We also find that arthropods and amphibians are less likely to have Action Plans than other species. In addition, we find no evidence that biases in listing or management have improved over time. Canadian species at risk recovery programs appear to be biased both in legal protection and management, disfavouring arthropods, amphibians and harvested fishes. If SARA is to fulfil its stated purpose, such biases must be directly addressed, through a transparent and formalised prioritisation system.
Stephanie J. Melles, Christopher Scarpone, Adisa Julien, Julie Robertson, Jennifer Bello Levieva, Courtney Carrier, Robert France, Sabrina Guvenc, Wai Ying Lam, Michelle Lucas, Alexus Maglalang, Keira McKee, Frances Okoye, Kayla Morales
Between 1987 and 1995, research papers published in five leading journals of applied ecology and conservation biology (AECB) were overwhelmingly produced by American and British authors. A significant proportion of overall variation in research productivity among nations could be explained by differences in gross national product (GNP). Here, we used bibliometric analyses for a comparative assessment to determine if geographical patterns of research changed or remained consistent between the periods, 1987–1995 and 2007–2015. Our results revealed an absence of a marked increase in geographical diversity of research. Imbalances persisted in global research efforts in five leading journals, with research productivity remaining significantly correlated to national differences in wealth. There is a disparity between where scientific research continues to be conducted and where hotspots of biodiversity are known to exist as indicated by our study and several other recent papers. This is an alarming finding as research is needed to establish conservation status, and work by others shows that the level of conservation spending is significantly correlated with mitigating biodiversity loss and improving species at risk status.
The composition, diversity, structure, leaf characteristics and productivity of plant communities in cloud forests vary along altitudinal gradients. These changes may drive interactions with insect herbivores; however, the empirical evidence is scarce. We evaluated seven leaf traits (specific leaf area, leaf density, leaf strength, C, N and water content, and C:N ratio) and insect herbivory of two shrub species (Xylosma flexuosa, Cinnamomum psychotrioides) at two elevations (1300 and 1600 m asl) in a Mexican cloud forest. We expected higher leaf herbivory at 1300 m, associated with a higher quality of leaf tissues (high specific leaf area, water and N content). Plant traits differed between species and elevation. In X. flexuosa, leaf density and C:N ratio were higher at 1600 m, while N content, leaf strength and C content were lower. In C. psychotrioides, only leaf density was higher at 1300 m. In accordance with these traits, herbivory was higher at 1300 m, but only in X. flexuosa. Herbivory levels ranged from 1% to 4.7% and were higher in X. flexuosa than in C. psychotrioides. Variation in leaf traits determines herbivory levels in X. flexuosa; however, perceived differences may also relate to biotic or abiotic factors driving herbivore abundance.
Nitraria tangutorum is a widely distributed shrub in the Jilantai Salt Lake at the southwest edge of Ulan Buh Desert. Due to their role in increasing soil fertility, nebkhas (coppice dunes) are regarded as important components of arid land ecosystems. Yet, despite their frequent occurrence, little information exists regarding their dust fall effect and influence range. We investigated the grain size distribution around N. tangutorum at a small scale (within 10 m) according to four wind directions and analyzed the spatial heterogeneity of particles. The amount of non-erodible particles (>0.85 mm) increased with distance from the shrub. The amount of erodible (<0.45 mm) and semi-erodible particles (0.45–0.85 mm) showed an opposite trend, indicating that the shrubs have a protective effect. The dominant particles around the shrubs were non-erodible due to long term accelerated wind erosion and subsequent removal of fine particles.
In fire-influenced savanna ecosystems, native and invasive exotic plants may use different abilities to coexist and compete for nutrients available in post-fire soil. The availability and uptake of nitrate by two C4 grasses (Urochloa brizantha (exotic invasive) and Axonopus siccus (native)) were characterized in an unburned area and in a recently burned area in the Cerrado of Southeastern Brazil. Ecophysiologic tests were performed to measure Nitrate Reductase Activity (NRA) and nitrate content in leaves and roots. Soil fertility was also analyzed. In the unburned area, organic matter (25.3 ± 2.4 g kg–1), phosphorus (19.0 ± 2.0 mg dm–3), and nitrate (19.9 ± 7.4 mg dm–3) levels were higher than in the recently burned area, which had 27% less cations in the soil. In comparison with soils from the recently burned and unburned areas, ashes of the recently burned area had higher pH, electrical conductivity and nitrate, potassium, and calcium contents. In both areas, the aboveground part of U. brizantha was more responsive to nitrate compared to A. siccus and both had low belowground NRA. This confirms the working hypothesis that the two species undergo distinct ecophysiologic processes and indicate the adaptive potential of U. brizantha to bypass soil nutrient limitation.
Objective estimates of crop loss due to herbivores and their comparison with the perception of people towards damage factors are required for the formulation of effective mitigation strategies. From October 2016 to May 2018, we used protected and unprotected plots to measure the extent of crop damage by blackbuck (Antilope cervicapra) and nilgai (Boselaphus tragocamelus) in the Abohar wildlife sanctuary (India). Land use and land cover (LULC) analysis of 2011–2012 data revealed that more than 90% of the sanctuary was under agricultural practices. The crop grain yield was significantly lower in unprotected plots. Mean (± SD) reduction in crop yield was significantly higher in mustard (40.12 ± 4.56%) than in cotton (26.50 ± 3.50%) and wheat (20.61 ± 3.94%) (p < 0.01). Perceived risk plots (based on 152 semi-structured interviews) revealed that local people working in the farming sector perceived nilgai to be the most crop depredating species followed by blackbuck, pests and stray animals. Participants manifested resentment toward the non-existence of crop damage compensation schemes. Managing wildlife habitats could also reduce the pressure on cultivated zones.
Roads and traffic have been implicated in population declines in a number of taxonomic groups. However, there is little research into the potential effects of roads or traffic on spiders. Here, we tested the prediction that there would be fewer aerially-dispersing (i.e., ballooning) spiders at high-traffic than low-traffic roads. We used custom-made sticky traps attached to a vehicle to collect ballooning spiders along 10 high-traffic–low-traffic rural road pairs in southeastern Ontario, Canada. We collected half as many spiders at high-traffic than low-traffic roads. This provides the first published evidence of negative traffic effects on ballooning spiders. Although consistent with our prediction that ballooning spiders are less abundant at high-traffic roads, there are several possible explanations for this finding. Further study is needed to investigate these explanations, including whether the observed traffic effect reflects reduced population sizes near high-traffic roads or reduced ballooning behaviour near high-traffic roads. If the former, then roads may represent a significant conservation concern for ballooning spider species.
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