Measuring the effectiveness of management interventions at regional scales by integrating ecological monitoring and modelling

Abstract

BACKGROUNDBecause of site‐specific effects and outcomes, it is often difficult to know whether a management strategy for the control of pests has worked or not. Population dynamics of pests are typically spatially and temporally variable. Moreover, interventions at the scale of individual fields or farms are essentially unreplicated experiments; a decrease in a target population following management cannot safely be interpreted as success because, for example, it might simply be a poor year for that species. Here, we argue that if large‐scale data are available, population models can be used to measure outcomes against the prevailing mean and variance. We apply this approach to the problem of rotational management of the weed Alopecurus myosuroides.RESULTSWe derived density‐structured population models for a set of fields that were not subject to rotational management (continuous winter wheat) and another group that were (rotated into spring barley to control A. myosuroides). We used these models to construct means and variances of the outcomes of management for given starting conditions, and to conduct transient growth analysis. We show that, overall, this management strategy is successful in reducing densities of weeds, albeit with considerable variance. However, we also show that one variant (rotation to spring barley along with variable sowing) shows little evidence for additional control.CONCLUSIONOur results suggest that rotational strategies can be effective in the control of this weed, but also that strategies require careful evaluation against a background of spatiotemporal variation. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Opportunities and challenges for harvest weed seed control in global cropping systems

“…Other approaches seek to maximize crop competitiveness through cultivar choice, crop choice or by the manipulation of crop sowing densities and sowing patterns . There is growing realization that the dominance of a few, often grass weeds is underpinned by narrow crop rotations that lead to the proliferation of well‐adapted weed species (e.g., black‐grass ( Alopecurus myosuroides ) in winter cereal crops in north‐western Europe) and this is beginning to result in more diverse crop rotations that alternate the sowing of winter and spring crops . The use of HWSC for targeting problematic weeds of European cropping systems has received relatively little attention despite the identification of opportunities in several studies that highlighted high seed‐retention levels …”

“…[61][62][63] There is growing realization that the dominance of a few, often grass weeds is underpinned by narrow crop rotations that lead to the proliferation of well-adapted weed species (e.g., black-grass (Alopecurus myosuroides) in winter cereal crops in north-western Europe) and this is beginning to result in more diverse crop rotations that alternate the sowing of winter and spring crops. 64 The use of HWSC for targeting problematic weeds of European cropping systems has received relatively little attention despite the identification of opportunities in several studies that highlighted high seed-retention levels. 3,8,9 With the depletion of herbicide resources, this area is now gaining some traction and newly funded research is beginning to explore weed-seed retention in major grass weeds (black-grass, Italian ryegrass and barnyard grass).…”

Testing the ability of unmanned aerial systems and machine learning to map weeds at subfield scales: a test with the weed Alopecurus myosuroides (Huds)

“…CNN learn a sparser connection between regions of an image than traditional neural network models by imposing spatial dependencies upon the pixels in the image . This may be of use when analysing weed distributions because these are spatially dependant . CNN do not use user‐defined features such as colour, shape or texture to learn from the data.…”

Suppressing Alopecurus myosuroides Huds. in Rotations of Winter-Annual and Spring Crops

“…There are studies that highlight the influence of spring barley on A. myosuroides densities [9,11,17]. Furthermore, recent studies have investigated the effect of herbicide mixtures and sequences, which are intended to prevent resistance development by using different MOA [18].…”