Earthworms Modulate Impacts of Soil Heterogeneity on Plant Growth at Different Spatial Scales

Soil heterogeneity (uneven distribution of soil nutrients and/or other properties) is ubiquitous in nature and can greatly affect plant growth. As earthworm activity can influence nutrient redistribution in the soil, we hypothesize that earthworms may alter the effect of soil heterogeneity on plant growth and this effect may depend on the scale of soil heterogeneity. To test these hypotheses, we grew the clonal grass Leymus chinensis in three soil treatments (heterogeneous large vs. heterogeneous small patch vs. homogeneous soil treatment) with or without earthworms [i.e., Eisenia fetida Savigny (Lumbricidae, epigeic redworm)]. In the heterogeneous treatments, the soil consisted of patches with and without 15N-labeled litter (referred to as high- and low-quality patches, respectively), and in the homogeneous treatment, the soil was an even mixture of the two types of soil patches. Biomass of L. chinensis was significantly higher in the high- than in the low-quality patches, showing the foraging response; this foraging response occurred at both scales and under both earthworm treatments. Compared to the homogeneous treatment, the heterogeneous large patch treatment increased biomass of L. chinensis without earthworms, but decreased it with earthworms. In contrast, biomass of L. chinensis in the heterogeneous small patch treatment did not differ from that in the homogeneous treatment, irrespective of earthworms. Belowground biomass was much greater in the heterogeneous small than in the heterogeneous large patch treatment without earthworms, but it did not differ between these two scale treatments with earthworms. In the heterogeneous treatments, soil 15N was greater in the high- than in the low-quality patches, but this effect became much weaker with than without earthworms, suggesting that earthworm activity homogenized the soil. We conclude that earthworms can change the impact of soil heterogeneity on plant growth via homogenizing the soil, and that this effect of earthworms varies with patch scale. Such scale-dependent interactive effects of soil heterogeneity and earthworms could be a potential mechanism modulating plant community structure and productivity.

Patch size does not always indicate bird species diversity: case in peri-urban tropical habitat in Riau, Indonesia

Larger patches generally are inhabited by higher species richness, including birds, as predicted by the island biogeography theory. The objective of this research was to reveal the response of bird species richness in different patch sizes in peri-urban habitat. The study site area was five patches (2 large patches near human activities, remote large patch with a small lake, small patch, corridor patch) of disturbed secondary shrub-forest in Riau University, Sumatra. Birds were observed using the standard point-counts in early morning and late afternoon (8 points/patch, 3 replicates, total 40 observation-hour) in March-April 2021. Species richness (S), Shannon-Wiener diversity indices (H’), Chao species prediction, and Bray-Curtis similarity indices (B) were calculated. Total of 979 individual birds were observed, consisted of 68 species from 28 families with B ranged from 0.573 to 0.846. Large patch with lake in remote area had the highest species richness (S:39 species, Chao:54) and H’ (3.097). However, two large patches closed to human activities had the lowest number of species (S:27, Chao:30, H’:2.908, and S:23, Chao:32, H’:2.938, respectively), even lower than small patch (S:30, Chao:40, H’:2.925) or corridor patch (S:34; Chao:51, H’:2.724). Clearly human disturbance and micro-habitat diversity affect species richness in a local scale.

Pridnestrovie

This work is the result of a research made by the author in 2010, under the guide of Fabio Bettanin, professor of Eastern Studies at the University of Naples “L’Orientale”. It focuses on Pridnestrovie, a small patch of land, legally belonging to the Moldavian Republic, located between the eastern bank of the Dniester River and the Moldovan border with Ukraine. Pridnestrovie, during the Soviet period hosted most of the industries located in the Moldavian Soviet Socialist Republic. In the aftermath of perestroika and the collapse of the USSR, Pridnestrovie declared, with the support of Moscow, its independence from Chinisau.

Direct Seamless Parametrization

We present a method for seamless surface parametrization. Recent popular methods first generate a cross-field, where curvature is concentrated at singular vertices. Next, in a separate step, the surface is laid out in the domain subject to derived seamlessness constraints. This decoupling of the process into two independent problems, each with its own objective, leads to suboptimal results. In contrast, our method solves both problems together using domain variables. The key ingredient to the robustness of our method is a rounding strategy based on local estimation. The insight is that testing a small patch to decide between two likely possibilities is a good estimator. Most distortion measures can be used with our method, which get minimized consistently throughout the pipeline. Our method also enables feature alignment, as well as alignment to principle curvatures, and isotropic and anisotropic scaling.

Field Experiments with a Totem Animal

This chapter follows Tetsuro Matsuzawa and his coworkers to their outdoor laboratory in Bossou, Guinea. Revered as the totem animal of the Manon and deprived of almost all primary rainforest, the Bossou chimpanzees had learned to live on human crops in an agricultural landscape. In contrast to Christophe Boesch's emphasis on so-called wild cultures, Matsuzawa speculated that historically, this chimpanzee community might have learned from the human population how to crack the oil palm nuts that local farmers cultivated. Field experiments allowed the primatologists to study how female immigrants passed on their knowledge of how to crack other kinds of nuts within the group. At this point, Japanese cultural primatology contradicted the Manon's mythological understanding of “their” apes as a bounded community of nonnatural animals. Chimpanzee road crossings provided an opportunity for a natural — or really “naturecultural” — experiment in an anthropogenic environment. Ethnoprimatologists collaborating with Matsuzawa studied the ecological interface between humans and primates and used their insights for conservationist ends. After a political conflict over the protection of a small patch of primary forest on a sacred hill, the Japanese primatologists took over the Manon's position that the livelihood of the Bossou chimpanzees was better served by plantations than by a nature reserve.

Out in the open: behavior’s effect on predation risk and thermoregulation by aposematic caterpillars

Warning coloration should be under strong stabilizing selection but often displays considerable intraspecific variation. Opposing selection on color by predators and temperature is one potential explanation for this seeming paradox. Despite the importance of behavior for both predator avoidance and thermoregulation, its role in mediating selection by predators and temperature on warning coloration has received little attention. Wood tiger moth caterpillars, Arctia plantaginis, have aposematic coloration, an orange patch on the black body. The size of the orange patch varies considerably: individuals with larger patches are safer from predators, but having a small patch is beneficial in cool environments. We investigated microhabitat preference by these caterpillars and how it interacted with their coloration. We expected caterpillar behavior to reflect a balance between spending time exposed to maximize basking and spending time concealed to avoid detection by predators. Instead, we found that caterpillars preferred exposed locations regardless of their coloration. Whether caterpillars were exposed or concealed had a strong effect on both temperature and predation risk, but caterpillars in exposed locations were both much warmer and less likely to be attacked by a bird predator (great tits, Parus major). This shared optimum may explain why we observed so little variation in caterpillar behavior and demonstrates the important effects of behavior on multiple functions of coloration.