Grazing Effects on Day Butterflies in a Mediterranean Woodland Ecosystem in Northern Israel

The effects of cattle grazing on biodiversity in Mediterranean woodlands are yet unknown. To assess these effects on diurnal butterflies, we conducted daytime surveys in the Mt. Meron nature reserve (northern Israel) in two habitats over two different years. In each habitat we chose one site that was grazed by cattle and, as a control, a similar but ungrazed site. Belt transects (5m wide), divided for 100m replications, were surveyed five times on ridges in 2015 (11 replications, 538 butterflies, 25 species), and nine times in valleys in 2016 (12 replications, 3,944 butterflies, 38 species). In both habitats, species similarity index between sites was high. Richness was higher in the ridge control and evenness was higher in the valley grazed site. In both habitats total abundance was ca. twofold higher in the control, and the abundance of woody affiliated butterflies was threefold higher in the control, probably due to overgrazing, which affects butterflies’ breeding niches. For batha polyphagous and oligophagous butterfly species, abundance was similar between the sites, and for a few of those, associated with increaser plants, it was even higher in the grazed sites. However, the batha monophagous species were significantly more abundant in the control. Monophagous and endangered species were found to be more sensitive to cattle grazing. We conclude that the current cattle grazing management in Mt. Meron reserve affects butterfly populations negatively. Therefore, we recommend more regulated grazing and early-season deferment precautions, along with designation of no-grazing areas in reserves.

High resilience of the mycorrhizal community to prescribed seasonal burnings in a Mediterranean woodland

Fire effects on ecosystems range from destruction of aboveground vegetation to direct and indirect effects on belowground microorganisms. Although variation in such effects is expected to be related to fire severity, another potentially important and poorly understood factor is the effects of fire seasonality on soil microorganisms. We carried out a large-scale field experiment examining the effects of spring versus autumn burns on the community composition of soil fungi in a typical Mediterranean woodland. Although the intensity and severity of our prescribed burns were largely consistent between the two burning seasons, we detected differential fire season effects on the composition of the soil fungal community, driven by changes in the saprotrophic fungal guild. The community composition of ectomycorrhizal fungi, assayed both in pine seedling bioassays and from soil sequencing, appeared to be resilient to the variation inflicted by seasonal fires. Since changes in the soil saprotrophic fungal community can directly influence carbon emission and decomposition rates, we suggest that regardless of their intensity and severity, seasonal fires may cause changes in ecosystem functioning.DeclarationsFundingThis research was co-supported by the United States-Israel Binational Science Foundation (BSF Grant 2012081) and Tel-Hai College.Conflicts of interest/Competing interestsWe declare no conflicts of interest and that this material has not been submitted for publication elsewhere.Ethics approvalNot applicableConsent to participateNot applicableConsent for publicationNot applicableAvailability of data and materialSequences were submitted to the National Center for Biotechnology Information Sequence Read Archive under accession numbers SRRXXX◻SRRXXX.Code availabilityNot applicableAuthors’ contributionsOO HS TB YO YC conceived and designed the experiment. SSL YA HM AT performed the experiment. SIG provided the pipeline scripts, and guidance in bioinformatics work and analyses. SLL OO HS wrote the paper and analyzed the data, and all authors contributed substantially to revisions.

N and P limitation shapes plant-AMF interactions across an aridity gradient

<p>Arbuscular mycorrhizal fungi (AMF) are important partners in plant nutrition, as they increase the range to scavenge for nutrients and can access resources otherwise occlude for plants. Under water shortage, when mobility of nutrients in soil is limited, AMF are especially important to acquire resources and can modulate plant drought resistance. Strategies of plants to cope with water and nutrient restrictions are shaped by the intensity of aridity. To investigate the effect of aridity on plant-AMF associations regarding drought resistance and plant nutrient acquisition, a <sup>13</sup>CO<sub>2</sub> pulse labeling was conducted across an aridity gradient. In a semiarid shrubland (66 mm a<sup>-1</sup>), a Mediterranean woodland (367 mm a<sup>-1</sup>), and a humid temperate forest (1500 mm a<sup>-1</sup>), root and soil samples were taken from 0-10 cm and 20-30 cm soil depth before labeling and at 1 day, 3 days, and 14 days after labeling. Carbon (C), nitrogen (N), and phosphorus (P) stocks as well as AMF root colonization, extraradical AMF biomass (phospho- and neutral lipid fatty acids (PLFA and NLFA) 16:1w5c), specific root length (SRL), and root tissue density (RTD) were measured. Plant C investment into AMF and roots was determined by the <sup>13</sup>C incorporation in 16:1w5c (PLFA and NLFA) and root tissue, respectively. Soil C:N:P stoichiometry indicated a N and P limitation under humid conditions and a P limitation in the topsoil under Mediterranean conditions. N stocks were highest in the Mediterranean woodland. A strong correlation of the AMF storage compound NLFA 16:1w5c to C:P ratio under semiarid conditions pointed to a P limitation of AMF, likely resulting from low P mobility in dry and alkaline soils. With increasing aridity, the AMF abundance in root (and soil) decreased from 45% to 20% root area. <sup>13</sup>C incorporation in PLFA 16:1w5c was similar across sites, while relative AMF abundance in topsoil (PLFA 16:1w5c:SOC) was slightly higher under semiarid and humid than under Mediterranean conditions, pointing to the importance of AMF for plant nutrition under nutrient limitation. Additionally, PLFA 16:1w5c contents in soil were higher with lower P availability in each site, underlining the role of AMF to supply P for plants under P deficiency. Under humid conditions (with strong N and P limitation) and semiarid conditions (with strong water limitation), root AMF colonization increased with lower N availability, displaying the role of AMF for plant N nutrition under nutrient and/or water shortage. Under humid and Mediterranean conditions, SRL decreased (0.5 and 0.3 times, respectively) and RTD increased (1.9 and 1.7 times, respectively) with depth, indicating a drought tolerance strategy of plants to sustain water shortage. Under semiarid conditions, SRL increased with depth (2.3 times), while RTD was consistently high, suggesting an increasing proportion of long-living fine roots with depth as scavenging agents for water. These relations point to a drought avoidance strategy of plants as adaptation to long-term water limitation. Under strong nutrient limitation, as under humid and semiarid conditions, AMF are crucial to sustain plant nutrition and to enhance plant resistance to water shortage.</p>