RESUMO
Plant species richness is an important property of ecosystems that is altered by grazing. In a semiarid environment, we tested the hypotheses that (1) small-scale herbaceous plant species richness declines linearly with increasing grazing intensity by large ungulates, (2) precipitation and percent sand interact with grazing intensity, and (3) response of herbaceous plant species richness to increasing intensity of ungulate grazing varies with patch productivity. During January-March 2012, we randomly allocated 50, 1.5-m × 1.5-m grazing exclosures within each of six 2500 ha study sites across South Texas, USA. We counted the number of herbaceous plant species and harvested vegetation in 0.25-m2 plots within exclosures (ungrazed control plots) and in the grazed area outside the exclosures (grazed treatment plots) during October-November 2012-2019. We estimated percent use (grazing intensity) based on the difference in herbaceous plant standing crop between control plots and treatment plots. We selected the negative binomial regression model that best explained the relationship between grazing intensity and herbaceous plant species richness using the Schwarz-Bayesian information criterion. After accounting for the positive effect of precipitation and percent sand on herbaceous plant species richness, species richness/0.25 m2 increased slightly from 0% to 30% grazing intensity and then declined with increasing grazing intensity. Linear and quadratic responses of herbaceous plant species richness to increasing grazing intensity were greater for the least productive patches (<15.7 g/0.25 m2) than for productive patches (≥15.7 g/0.25 m2). Our results followed the pattern predicted by the intermediate disturbance hypothesis model for the effect of grazing intensity on small-scale herbaceous plant species richness.
RESUMO
OBJECTIVE: To compare the clinical course of patients with class III, IV and V lupus nephritis (LN) treated at Hospital Universitario Cruces (CC) and at Bordeaux University Hospital (BC). METHODS: The Lupus-Cruces nephritis protocol combines pulses of 125mg of methyl-prednisolone with each fortnightly pulse of cyclophosphamide and prednisone ≤30mg/day with tapering over 12-14weeks until 2.5-5mg/day. The BC followed international lupus nephritis guidelines, combining high-dose prednisone and either mycophenolate mofetil or cyclophosphamide, followed by maintenance therapy with low dose prednisone and immunosuppressive drugs. The main outcomes were complete renal remission (CR) and glucocorticoid toxicity. RESULTS: 44 patients from BC and 29 from CC were included. The mean maximum prednisone dose was 42.5 (BC) vs. 21mg/day (CC), p<0.001. The average 6-month prednisone dose was 21 (BC) vs. 8.3mg/d (CC), p<0.001.The mean number of methyl-prednisolone pulses was 3 (BC) vs. 9.3 (CC), p<0.001. HCQ was used by 64% (BC) vs. 100% (CC), p<0.001. CR rates were 30% (BC) vs. 69% (CC), p=0.001, and 42% (BC) vs. 86% (CC), p<0.001, at 6 and 12months, respectively. Patients from the CC more frequently achieved CR (adjusted HR 3.8, 95%CI 2.05-7-09). The number of pulses of methyl-prednisolone were associated with CR (adjusted HR 1.09, 95%CI 1.03-1.15). Patients in the CC had a lower risk of GC-related side effects (adjusted HR 0.19, 95%CI 0.04-0.89). CONCLUSION: The Lupus-Cruces nephritis protocol improves the outcome of LN. Repeated methyl-prednisolone pulses help reduce the dose of oral glucocorticoids and enhance clinical response.
