Diet of the marsh deer in the Paraná River Delta, Argentina—a vulnerable species in an intensive forestry landscape

Abstract

The marsh deer (Blastocerus dichotomus) is the largest deer native to South America, occurring in wetlands and marshy habitats. The southernmost population of the species is found in the Paraná River Delta, Argentina, in a wetland system highly modified by intensive forestry activity. Foresters perceive high levels of economic losses attributed to deer herbivory which drives marsh deer poaching. We carried out the first study of the dietary composition of the marsh deer in this wetland by using microhistological analysis of feces collected seasonally. Seventy-three food items were identified in the marsh deer diet, but only eight had frequencies of > 3% in the annual diet. Macrophytes dominated the diet throughout the year (seasonal percent frequencies 31-42%) due to the high occurrence of Ludwigia bonariensis (24% of average seasonal frequency). Trees, vines, forbs, and shrubs contributed less frequently to the diet, while grasses and grass-like plants were marginally represented (i.e., < 2%). Exotic plant species comprised 38% of the annual diet, and tree species of commercial importance (Salix sp. and Populus R22) were poorly represented (≤ 5.5% per season). The marsh deer in this wetland could be categorized as a browser, differing from the feeding behavior reported for the species in the Brazilian Pantanal (grazer-browser) and suggesting a trophic elasticity in this cervid. Since commercial tree species comprised a very small portion of the diet of this deer, a change in producers' perception toward the species is needed to diminish this conflict, and our data are important to develop context-specific conservation and management solutions.

Diets and habitat selection of takhi and red deer in Hustai National Park, Mongolia

“…However, since this study was done within a single site using the same methods, comparisons show relative similarities and differences between the species and among the seasons. Although our sample size was limited compared to other studies (Suter et al 2004, Zweifel-Schielly et al 2012, it is similar to others (Marin et al 2020) and showed significant differences in the main food plants like grasses, dicots and fiber (Fig. 2).…”

Unmanned aerial vehicle surveys reveal unexpectedly high density of a threatened deer in a plantation forestry landscape

“…Plantations, numerous streams, artificial channels and small marshlands are embedded within this landscape, and this has resulted in areas of high plant diversity, including a community of macrophytes (i.e. aquatic plants that grow in or near water), the main food of marsh deer in this delta (Marin et al, 2020). Consequently, this modified landscape appears to offer marsh deer both suitable forage and habitat conditions.…”

“…Marsh deer in the lower delta of the Paraná River are exploiting a matrix of commercial tree plantations, and new dietary resources (invasive exotic plant species; Marin et al, 2020), matters that have not been observed elsewhere in the species' range. This apparent ecological flexibility of the marsh deer may provide it with greater resilience to land-use pressures in the study region.…”

Sharpening the mesowear tool: geometric morphometric analysis of cusp shape and diet in ruminants

“…B = browser, G = grazer; M = mixed feeder; F = frugivore. References for a priori diet classifications: (1)Bannikov, 1976; (2)Barrio, 2013; (3)Baskin and Danell, 2003; (4) Campos-Arceiz et al, 2004; (5)Clemente et al, 2009; (6) Codron et al, 2007; (7) Cook, 2002; (8) Dagg, 2014; (9) Davis et al, 2008; (10) Djagoun et al, 2013; (11) Flores-Miyamoto et al, 2005; (12) Gagnon and Chew, 2000; (13) Hart and Hart, 1989); (14)Heffelfinger, 2018; (15) Hejcmanová et al, 2010; (16) Hofmann and Roth, 2003; (17) Jiang et al, 2002; (18) Johnsingh and Sankar, 1991; (19) Leslie, 2008; (20) Marin et al, 2020; (21) Müller et al, 2011; (22) O'shaughnessy et al, 2014; (23) Owen-Smith, 1997; (24) Pinder and Grosse, 1991; (25) Renecker and Schwartz, 1997; (26) Schaller, 1967; (27) Sempéré et al, 1996; (28) Seri et al, 2018; (29) Sokolov, 1974; (30) Tomas and Salis, 2000; (31) Tripathi et al, 2019; (32) Tuboi and Hussain, 2016; (33) Wegge et al, 2006; (34) Wilson and Mittermeier, 2011; (35) Watter et al, 2020Watter et al, . 10.3389/fevo.2023 Frontiers in Ecology and Evolution 06 frontiersin.org…”