## 1 Introduction  
Montado is a multifunctional agro-silvo-pastoral ecosystem, characteristic of the Mediterranean region [1]. This ecosystem is made up of four fundamental components--soil, pasture, trees, and animals--which are interconnected, influencing each other [2]. Montado is also influenced by the Mediterranean climate, characterized by a great variability in precipitation and temperature in each year and between years [3]. For these reasons, Montado is considered an ecosystem of great complexity and variability, both spatial and temporal [4].  
Although at times the intervention of humans has proven to be harmful to the Montado ecosystem, their role is fundamental for preserving the attributes that characterize Montado (non-climax community) so that it does not degenerate again into a Mediterranean forest.  
This review takes a journey through time, from the beginnings of Montado to the present day. Our intention is to show research work carried out in Montado or in similar ecosystems and production systems, with the aim of improving production efficiency, contributing to the conservation of natural resources, and ensuring animal welfare. The focus emphasizes the last 20 to 30 years, aiming at characterizing and describing the Montado ecosystem. Its conservation/improvement is essential for environmental, productive, social, and economic reasons. To make this happen, it is crucial to monitor this ecosystem. Understanding its genesis, as well as the technological tools and technical options for agriculture, can lead to the greater profitability of production systems without compromising environmental issues and animal welfare.  
One of modern agriculture's significant challenges is the creation of production systems that combine low input levels with high food production efficiency and minimal environmental impacts [5]. These authors' statements imply the concept of sustainable intensification, which is very important nowadays in agricultural systems. Therefore, sustainable intensification involves improving the efficiency of production systems and increasing productivity per hectare, with a minimum use of production factors.  
The first steps consist usually of the characterization and evaluation of the soil and pasture. Traditional methods include collecting samples in a limited area and subsequent laboratory procedures [6]. These processes imply great investment in terms of time and human resources, making them quite expensive [7]. However, several expeditious technologies currently allow for characterization and evaluation without resorting to traditional methods, allowing for fast, large-scale measurements while correlating well with laboratory results [8].  
In recent years, two or three research groups have carried out research work in Montado and Dehesa (Portugal and Spain, respectively). In Portugal, the research group's works are authored by [PERSON] et al., and in Spain, the teams are authored by [PERSON] et al. and [PERSON] et al.  
We are still determining the existence of other published review works on Montado, which simultaneously integrate its general characterization and the expeditious technologies available for Montado monitoring and grazing issues. This seeks to pioneer concerning the description and integration of the Montado ecosystem as a whole.  
This article aims to: (i) describe and characterize the Montado ecosystem, as an agro-silvo-pastoral system; (ii) reveal experimental tests carried out and technologies used or with the potential to be used in the monitoring of Montado; (iii) acknowledge other works carried out in similar and different conditions from ours, for eventual replication or not, in the Montado; (iv) provide a structure for future research work.