Process followed by GPHA

Plant Health in Plant Populations; in Cultivated Plants and in Natural Ecosystems. Looking at plant health, different ideas come to mind: one may want to look at plants, rather than crops, if plants are cultivated (and when looking at crop plants, looking at plants within a crop). One may want to look at plant health in systems other than those intended (or designed) for agricultural production; and one may want to consider natural ecosystems.

The Global Plant Health Assessment considers the health of plants from the angle of infectious diseases (that are reducing) plant health – and not at abiotic stresses (heat, water stress, pollutions and toxicants of very different kinds, and soil limitations and toxicities). Actually, it is non-health, that is to say, disease, which can be defined and measured - not health. The Assessments will thus consider: viruses, bacteria, fungi, oomycetes, nematodes, and possibly other organisms (parasitic plants) which behave (specialisation/adaptation) as plant pathogens.

The assessment considers plant health as a whole, and not specific plant diseases, considered piece-meal. No easy quantification of plant health, as a whole, is imaginable. Therefore, the Assessment engages in the collection of qualitative, but science- and fact-based, expert opinions on the state of health of plants. This type of qualitative assessment has been conducted when the Millennium Ecosystem Assessment was undertaken. The present Assessment uses a similar approach to represent results.

It is impossible to conduct this assessment for all plant species in the biosphere. Stepping away from the “plant” scale, the following approach is used to focus on plants:

Organisation:

Each Plant System in a chosen ecoregion of the world is considered by a team (a lead scientist and a few experts), and considers plant health of this plant systems. The metric to assess plant health is based on the ecosystem services generated by Plant System, their increase, stability, or decrease.

Building blocks: Four questions

The two first questions to address are

Q1: in the past 30 years, how to characterise plant health?, on a scale, from “excellent” to “poor”

Q2: over the recent 10 years, how has plant health evolved on the considered plant? on a scale, from “improving”, to “stable”, to “declined”

Answers must be documented with examples and references.

The two next questions refer to the consequences of the status of plant health and the trend of plant health on the generation of (ecosystem) services

Q3: In the past 30 years, has the generation – as affected by plant disease – of the considered service been adequate? on a scale, from “excellent” to “poor”

Q4: over the recent 10 years, how has the generation – as affected by plant disease – of this service evolved? on a scale, from “improving”, to “stable”, to “declining”

How should questions be answered

For each [Ecoregion x System] combination considered, represented by one (or a few) plant(s), four, or sometimes 6, questions are therefore to be answered. These questions are:

Q1: in the past 30 years, how to characterise plant health?, on a scale, from “excellent” to “poor”

Q2: over the recent 10 years, how has plant health evolved on the considered plant? on a scale, from “improving”, to “stable”, to “declined”

and for each (maximum 2) ecosystem service:

Q3: In the past 30 years, has the generation – as affected by plant disease – of the considered service been adequate? on a scale, from “excellent” to “poor”

Q4: over the recent 10 years, how has the generation – as affected by plant disease – of this service evolved? on a scale, from “improving”, to “stable”, to “declining”