Standardized Precipitation Evapotranspiration Index (Megachilidae)

Knowledge graph centered on Standardized Precipitation Evapotranspiration Index (Megachilidae) with 40 nodes and 127 connections. Top connected: Bombus, Ligusticum porteri, Bombus terrestris, Bombus appositus, Bombus impatiens.

Method synopsis

Standardized Precipitation Evapotranspiration Index calculated over 12-month water-year periods to quantify drought severity, incorporating both precipitation and temperature effects on water balance.

Synthesized from method descriptions across 1 paper using this protocol.

Procedure from a recent peer-reviewed implementation

Steps below were extracted from the most recent peer-reviewed implementation of this protocol in the corpus — Up high, hot and dry: Individual reproductive output in subalpine bees declines with increasing drought severity (2025), Global Change Biology. Implementations in other papers (listed below) may differ.

1. Calculate climate metrics
   Daily precipitation data acquired for each site and year using parameter-elevation regressions on independent slopes model (PRISM Group, Oregon State University). Drought severity calculated using Standardized Precipitation Evapotranspiration Index (SPEI) over 12-month 'water-year' periods from September 1 of previous year to August 31 of current year. Summer temperature averaged over four-month period from May to August. Summer precipitation summed over same May-August period.
   Quantities: 12-month water-year periods, 4-month summer periods (May-August), daily precipitation and temperature dataDuration: Calculated annually for each study year 2013-2022Conditions: Water-year calculations from September 1 to August 31, summer metrics May-August
   Equipment: PRISM climate data, R package SPEI for drought calculations

Typical Equipment

• R package SPEI
• PRISM climate data

Output Measurements

• water-year drought severity
• summer drought severity

Papers Using This Protocol (1)

Species Studied With This Protocol