Habitat use at fine spatial scale: how does patch clustering criteria explain the use of meadows by red deer ?

Large mammalian herbivores are keystone species in different ecosystems. To mediate the effects of large mammalian herbivores on ecosystems, it is crucial to understand their habitat selection pattern. At finer scales, herbivore patch selection depends strongly on plant community traits and therefore its understanding is constrained by patch definition criteria. Our aim was to assess which criteria for patch definition best explained use of meadows by wild, free-ranging, red deer (Cervus elaphus) in a study area in Northeast Portugal. We used two clustering criteria types based on floristic composition and gross forage classes, respectively. For the floristic criteria, phytosociological approach was used to classify plant communities, and its objectivity evaluated with a mathematical clustering of the floristic relevés. Cover of dominant plant species was tested as a proxy for the phytosociological method. For the gross forage classes, the graminoids/forbs ratio and the percentage cover of legumes were used. For assessing deer relative use of meadows we used faecal accumulation rates. Patches clustered according to floristic classification better explained selection of patches by deer. Plant community classifications based on phytosociology, or proxies of this, used for characterizing meadow patches resulted useful to understand herbivore selection pattern at fine scales and thus potentially suitable to assist wildlife management decisions

Data from: High-nature-value grasslands have the capacity to cope with nutrient impoverishment induced by mowing and livestock grazing

1. Management of high-nature-value (HNV) grasslands follows agri-environmental schemes across large areas of Europe. Long-term agreements and restrictions of fertilizers cause soil nutrient impoverishment, but remarkably this quite often does not reduce biomass production. Therefore, we tested how species-rich vegetation copes with nutrient impoverishment under the most frequently used treatments, that is summer mowing and livestock grazing. 2. During 2011–2012 we studied, simultaneously, plant species composition, soil and biomass chemical properties in two equally designed experiments where mowing, grazing or leaving fallow have been applied since 2004. We asked whether soil-based (Corg : Ntot, plant-available P and K) and plant-based measures (N : P, N : K, K : P ratios and N-, P-, K-nutrition indices) indicate the same pattern of nutrient limitation as the observed productivity gradient. 3. Seven years of management application resulted in the lowest plant-available P under grazing and the lowest plant-available K under mowing, but neither grazed nor mown plots produced less biomass than fallow ones. Grazing supported dominance of grasses while mowing that of non-leguminous forbs. 4. Projection of nutrition indices to a common framework with nutrient ratios suggests that critical thresholds for diagnosis of nutrient limitation are a function of N deficiency. At biomass production of 2 t ha−1 a N-nutrition index of 50 yielded threshold N : P = 14·0; hence, all our treatments with N : P of 9·9–12·5 should be N limited. 5. Inspecting the productivity gradient separately for each management, we found only soil Corg : Ntot negatively related to biomass production in mown plots indicating N limitation. However in grazed plots, positive association of biomass production with plant-available P and negative with biomass N : P and N : K suggested PK co-limitation. 6. Synthesis and applications. Mowing and grazing induced different patterns of soil nutrient impoverishment and nutrient limitation, but they did not reduce biomass production of high-nature-value grasslands. Non-leguminous forbs prevailing under mowing precluded shortage of P, while grasses dominating under grazing efficiently captured N. We recommend designing agri-environmental measures that will encourage alternating mowing and grazing. This should promote coexistence of multiple forbs and grasses, balance nutrient limitation and ensure stable biomass production under future low-input scenarios

Calcium plus magnesium indicates digestibility: the significance of the second major axis of plant chemical variation for ecological processes

Data file contains 2 sheets with following information: (1) simultaneous measurements of plant biomass properties and vegetation records from field sampling of two long-term grassland management experiments in 2011-2012; plant species abbreviations consist of first three letters from the genus name and first three letters from the species name; community weighted traits were calculated from species biomass proportions and their respective trait values extracted from databases or literature (can be found in supporting information of the article: Appendix S1); (2) List of species abbreviations and respective scientific names. Plant names follow nomenclature: Kubát, K., Hrouda, L., Chrtek, J., Kaplan, Z., Kirschner, J. & Štěpánek, J. (2002) Key to the Flora of the Czech Republic. Academia, Praha, Czech Republic

Plant Trait Assembly Affects Superiority of Grazer's Foraging Strategies in Species-Rich Grasslands

<div><p>Background</p><p>Current plant – herbivore interaction models and experiments with mammalian herbivores grazing plant monocultures show the superiority of a maximizing forage quality strategy (MFQ) over a maximizing intake strategy (MI). However, there is a lack of evidence whether grazers comply with the model predictions under field conditions.</p><p>Methodology/Findings</p><p>We assessed diet selection of sheep (<i>Ovis aries</i>) using plant functional traits in productive mesic <i>vs.</i> low-productivity dry species-rich grasslands dominated by resource-exploitative <i>vs.</i> resource-conservative species respectively. Each grassland type was studied in two replicates for two years. We investigated the first grazing cycle in a set of 288 plots with a diameter of 30 cm, i.e. the size of sheep feeding station. In mesic grasslands, high plot defoliation was associated with community weighted means of leaf traits referring to high forage quality, i.e. low leaf dry matter content (LDMC) and high specific leaf area (SLA), with a high proportion of legumes and the most with high community weighted mean of forage indicator value. In contrast in dry grasslands, high community weighted mean of canopy height, an estimate of forage quantity, was the best predictor of plot defoliation. Similar differences in selection on forage quality <i>vs</i>. quantity were detected within plots. Sheep selected plants with higher forage indicator values than the plot specific community weighted mean of forage indicator value in mesic grasslands whereas taller plants were selected in dry grasslands. However, at this scale sheep avoided legumes and plants with higher SLA, preferred plants with higher LDMC while grazing plants with higher forage indicator values in mesic grasslands.</p><p>Conclusions</p><p>Our findings indicate that MFQ appears superior over MI only in habitats with a predominance of resource-exploitative species. Furthermore, plant functional traits (LDMC, SLA, nitrogen fixer) seem to be helpful correlates of forage quality only at the community level.</p></div

Linear mixed effect models where plot defoliation was dependent variable and every biomass proportion of taxonomic group or community weighted mean of quantitative trait was treated in the separate model and considered as fixed effect, while site code in a given year as random effect (degrees of freedom 1, 283).

<p>Linear mixed effect models where plot defoliation was dependent variable and every biomass proportion of taxonomic group or community weighted mean of quantitative trait was treated in the separate model and considered as fixed effect, while site code in a given year as random effect (degrees of freedom 1, 283).</p

Characteristics of sites within both grassland types, biotic parameters averaged over both years of observation.

<p>Note: MAT – mean annual temperature, MAP – mean annual precipitation <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0069800#pone.0069800-Tolasz1" target="_blank">[40]</a>, CSH – compressed sward height measured with rising-plate meter <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0069800#pone.0069800-Correll1" target="_blank">[21]</a>: figure behind ‘±’ standard deviation.</p

Plot defoliation, biomass proportions of plant taxonomic groups and plot community weighted means of traits (including their abbreviations) averaged over both sites and years within grassland type, standard deviation in parentheses.

<p>Plot defoliation, biomass proportions of plant taxonomic groups and plot community weighted means of traits (including their abbreviations) averaged over both sites and years within grassland type, standard deviation in parentheses.</p

Sheep selectivity (Jacobs' D) within plots in mesic and dry grasslands.

<p>Selectivity for (A) taxonomic groups of species; (B) sum of species possessing higher trait values than plot specific community weighted trait mean. Selectivity was evaluated with Jacobs' D selectivity index ranging from −1 to 0 (avoidance) and from 0 to +1 (preference). Squares show means with 95% confidence interval (CI). Selectivity for a particular group/trait was considered significantly positive/negative if CI did not involve a zero value.</p