They acknowledge that they need to develop better methods for field ecological studies, including better baseline data with which to compare new crops (ICSU). Scientists agree that the use of conventional agricultural pesticides and herbicides has damaged habitats for farmland birds, wild plants and insects and has seriously reduced their numbers (ICSU, GM Science Review Panel, Royal Society). Transgenic crops are changing chemical and land-use patterns and farming practices, but scientists do not fully agree whether the net effect of these changes will be positive or negative for the environment (ICSU).