Landscape Characteristics Affecting Small Mammal Occurrence in Heterogeneous Olive Grove Agro-Ecosystems

Abstract

Understanding how small mammals (SM) are associated with environmental characteristics in olive groves is important to identify potential threats to agriculture and assess the overall conservation value and functioning of agro-ecosystems. Here, we provide first insights on this topic applied to traditional olive groves in northeast (NE) Portugal by assessing the landscape attributes that determine SM occurrence, focusing on one species of conservation concern (Microtus cabrerae Thomas 1906) and one species often perceived as a potential pest of olives (Microtus lusitanicus Gerbe 1879). Based on SM genetic non-invasive sampling in 51 olive groves and surrounding habitats, we identified seven rodent species and one insectivore. Occupancy modelling indicated that SM were generally less detected within olive groves than in surrounding habitats. The vulnerable M. cabrerae reached a mean occupancy (95% CI) of 0.77 (0.61–0.87), while M. lusitanicus stood at 0.37 (0.24–0.52). M. cabrerae was more likely to occur in land mosaics with high density of agricultural field edges, while M. lusitanicus was more associated with high density of pastureland patches. Overall, our study suggests that the complex structure and spatial heterogeneity of traditionally managed olive grove agro-ecosystems may favor the occurrence of species-rich SM communities, possibly including well-established populations of species of conservation importance, while keeping potential pest species at relatively low occupancy rates.

Abundance and Population Structure of Small Rodents in Fruit and Berry Farms

“…Despite recent studies on small rodents in agroecosystems [ 18 , 75 , 76 , 77 ], fruit farms are one of the least addressed topics [ 24 , 25 , 78 ]. Our previous publications [ 26 , 27 , 79 ] have not addressed aspects of small rodent population structure, annual and seasonal dynamics of their abundance, and the correlation of relative abundance with reproductive parameters.…”

“…Traditionally, orchards are not only a source of food, but also a source of well-being for people and wildlife [ 23 ]. As a habitat with different conditions for animals than crop fields, orchards can support a wide diversity of small mammals [ 20 , 24 , 25 ]. The edge effect, which leads to a reduction in rodents in agricultural habitats in the middle of larger areas [ 19 ], has not been investigated in orchards.…”

Shrews Under-Represented in Fruit Farms and Homesteads

“…Despite some data on shrews in agricultural and anthropogenic habitats [ 29 , 30 , 31 , 32 , 33 , 34 , 35 ], agro-ecological studies are mostly limited to rodent communities [ 54 , 55 , 56 , 57 , 58 , 59 , 60 ]. Studies on insectivores in anthropogenic habitats are mostly limited to birds and bats [ 61 , 62 , 63 , 64 , 65 , 66 ], and the same applies to agricultural areas [ 67 , 68 , 69 , 70 ].…”

“…Crocidura shrews (21%), however, were associated with open and cultivated habitats, while Neomys shrews were preyed upon along canals and ditches [ 32 ]. Elsewhere, the Greater white-toothed shrew ( Crocidura russula ) accounted for 16.1% of the small mammals recorded in olive groves in Portugal [ 33 ], whereas in Serbia, in a mosaic of clover, maize, wheat, and soybean fields, all Soricidae accounted for 23.6% of the prey of owls, of which S. araneus accounted for 5.19% and S. minutus for 0.86% [ 34 ]. In the suburbs of Warsaw (Poland), S. araneus accounted for 4.9% and S. minutus for 0.2% of the prey of S. aluco [ 35 ].…”

Detection of hepatitis E virus genotype 3 in an Algerian mouse (Mus spretus) in Portugal

“…1 ). The wild small mammal fecal samples ( n = 290) were collected during ecological studies (Barão et al 2022 ; Lux et al 2023 ) from six different species in the spring of 2020 in the Northeast region of Portugal (Trás-os-Montes). Wild small mammal droppings were collected from 24 different sampling units, representing six different habitat types and were from one insectivore (greater white-toothed shrew, Crocidura russula , n = 47) and from five species of rodents, including two species of the family Muridae (wood mouse, Apodemus sylvaticus , n = 43; Algerian mouse, Mus spretus , n = 48) and three species of the family Cricetidae (southwestern water vole, Arvicola sapidus , n = 52; Cabrera’s vole, Microtus cabrerae , n = 49; Lusitanian pine vole, Microtus lusitanicus , n = 51).…”