## 1 Introduction  
Large mammalian herbivores such as European boson (_Bison bonasus_), aurochs (_Bos primigenius_), reindeer (_Rangifer tarandus_), moose (_Alces alc_), and wild horse (_Equis ferus_) occurred simultaneously in Europe and formed the megaaherbivore community during the Holocene [1, 2]. As they shape the structure and functioning of terrestrial ecosystems, they are seen as keystone species in maintaining open landscapes [3, 4, 5, 6, 7] and have a significant impact on population and community structure in a broad range of ecosystems [8, 9, 10, 11]. Because of natural and anthropogenic reasons like landscape change, habitat fragmentation, habitat loss, and hunting, populations of large herbivores were reduced or exterminated [12, 13, 14, 15]. In the late 20 th century, conservation strategies focusing on restoration of keystone species and the establishment of wilderness areas were increasingly implemented [7, 16]. Here, we regard rewilding as an approach to NATURA 2000 habitat conservation that enables natural processes to restore degraded landscapes [17]. We expect that wildlife's natural rhythms create wilder, more biodiverse habitats. Rewilding large mammals can have strong ecological effects on habitat heterogeneity and primary production as well as seed dispersal, and is of worldwide relevance [11; 18; 19; 20; 21]. In Europe, large mammals like equids (_Equus_ spp.) and European bison (_Bison bonasus_) are making a comeback by being introduced into various habitats [7; 22; 23; 24; 25]. European bison (_Bison bonasus_) and [PERSON]'s horse (_Equus fernus przewalskii_) have been successfully restored after both species had become extinct in the wild. European bison are the largest terrestrial mammal in Europe. Their former distribution covered large parts of the European continent [14; 26]. [PERSON]'s horses were prevalent at the Eurasian steppes, but competition with livestock as well as hunting caused the species's decline [27]. Sustainable management and conservation efforts of species require solid knowledge about basic ecology and behavior [7; 28; 29; 30; 31; 32; 33]. However, rewilding experiments and empirical studies with large herbivores are still few in number [7; 33; 34]. To exploit the entire potential of large mammals for nature conservation and promotion of biodiversity, knowledge of the ecology of the candidate species is needed. In this context, information about habitat preferences is required to optimize the benefits of ecological restoration purposes, as well as to ensure animal welfare, as diet highly depends on available plant species [7; 24; 33; 35]. Valid information about food competition between [PERSON]'s horse and European bison in a rewilding context is still lacking. One methodological reason for this was the difficulty in describing the diversity of the available habitat adequately in time and space in former times. Today, the Earth's surface is recorded by a huge amount of optical satellites that are capable of resolving habitat characteristics spatially with pixel sizes of less than 10 m over large periods. Intra-annual as well as multi-year observations provide dense image datasets that describe the spatial distribution and phenological development of vegetation stands over large areas [36; 37; 38; 39]. In recent studies, optical satellite remote sensing has been proven to accurately map various habitat categories such as Natura 2000 grasslands [40; 41; 42], shrublands [43; 44], forests [45; 46; 47], or mites [48; 49]. It could further be shown that recent advances in machine learning techniques improve the accuracy of habitat classification for mapping purposes [50; 51; 52]. This study aims to incorporate the temporal and spatial dimensions of habitat distribution using such remote sensing techniques. We hypothesize that diet preferences differ seasonally within and between European bison and [PERSON]'s horse. Combining data on diet preferences and habitat distribution, we assume that competition for resources occurs mainly in winter, when forage becomes scarcer.