TY  - JOUR
AU  - Nikolić, Tijana
AU  - Arok, Maja
AU  - Radišić, Dimitrije
AU  - Mirč, Marko
AU  - Velaja, Lea
AU  - Milić, Dubravka
AU  - Ćirović, Duško
PY  - 2020
UR  - http://www.serbiosoc.org.rs/arch/index.php/abs/article/view/4485
UR  - https://radar.ibiss.bg.ac.rs/handle/123456789/3654
AB  - Understanding the spatial and temporal effects of variable environmental conditions on demographic characteristics is important in order to stop the decline of endangered-species populations. To capture interactions between a species and its environment, in this work the demographic traits of the European ground squirrel (EGS), Spermophilus citellus, were modeled as a function of agricultural landscape structure. The habitat suitability index was determined for 20 localities within the study area based on habitat use, management and type. After mapping the habitat patch occupancy in the field, crop cover maps, the average normalized difference vegetation index (NDVI) and automated water extraction index (AWEI) were obtained from satellite images covering the period 2013-2015. This data was used to develop population-level generalized linear models (GLMs) and individual-level conditional mixed-effects models (GLMMs) in R package Ime4, focusing on the key demographic traits of the EGS. The land composition and patch carrying capacity (PCC) are the key determinants of the endangered EGS population size, while system productivity is the main factor influencing individuals’ body condition after monitoring for variations across sampling years and age classes. The proposed landscape structural models show that human activities and abiotic factors shape the demographic rates of the EGS. Thus, to conserve threatened species, an appropriate focus on the spatial adaptation strategies should be employed.
T2  - Archives of Biological Sciences
T1  - Endangered species’ trait responses to environmental variability in agricultural settings
IS  - 1
VL  - 72
DO  - 10.2298/abs190715061n
SP  - 13
EP  - 21
ER  - 

@article{
author = "Nikolić, Tijana and Arok, Maja and Radišić, Dimitrije and Mirč, Marko and Velaja, Lea and Milić, Dubravka and Ćirović, Duško",
year = "2020",
abstract = "Understanding the spatial and temporal effects of variable environmental conditions on demographic characteristics is important in order to stop the decline of endangered-species populations. To capture interactions between a species and its environment, in this work the demographic traits of the European ground squirrel (EGS), Spermophilus citellus, were modeled as a function of agricultural landscape structure. The habitat suitability index was determined for 20 localities within the study area based on habitat use, management and type. After mapping the habitat patch occupancy in the field, crop cover maps, the average normalized difference vegetation index (NDVI) and automated water extraction index (AWEI) were obtained from satellite images covering the period 2013-2015. This data was used to develop population-level generalized linear models (GLMs) and individual-level conditional mixed-effects models (GLMMs) in R package Ime4, focusing on the key demographic traits of the EGS. The land composition and patch carrying capacity (PCC) are the key determinants of the endangered EGS population size, while system productivity is the main factor influencing individuals’ body condition after monitoring for variations across sampling years and age classes. The proposed landscape structural models show that human activities and abiotic factors shape the demographic rates of the EGS. Thus, to conserve threatened species, an appropriate focus on the spatial adaptation strategies should be employed.",
journal = "Archives of Biological Sciences",
title = "Endangered species’ trait responses to environmental variability in agricultural settings",
number = "1",
volume = "72",
doi = "10.2298/abs190715061n",
pages = "13-21"
}

Nikolić, T., Arok, M., Radišić, D., Mirč, M., Velaja, L., Milić, D.,& Ćirović, D.. (2020). Endangered species’ trait responses to environmental variability in agricultural settings. in Archives of Biological Sciences, 72(1), 13-21.
https://doi.org/10.2298/abs190715061n

Nikolić T, Arok M, Radišić D, Mirč M, Velaja L, Milić D, Ćirović D. Endangered species’ trait responses to environmental variability in agricultural settings. in Archives of Biological Sciences. 2020;72(1):13-21.
doi:10.2298/abs190715061n .

Nikolić, Tijana, Arok, Maja, Radišić, Dimitrije, Mirč, Marko, Velaja, Lea, Milić, Dubravka, Ćirović, Duško, "Endangered species’ trait responses to environmental variability in agricultural settings" in Archives of Biological Sciences, 72, no. 1 (2020):13-21,
https://doi.org/10.2298/abs190715061n . .

TY  - JOUR
AU  - Nikolić, Tijana
AU  - Radišić, Dimitrije
AU  - Ćosić, Nada
AU  - Díaz-Delgado, Ricardo
AU  - Milić, Dubravka
AU  - Vujić, Ante
AU  - Ćirović, Duško
PY  - 2019
UR  - http://link.springer.com/10.1007/s10531-019-01810-y
UR  - https://radar.ibiss.bg.ac.rs/handle/123456789/3438
AB  - Grasslands are one of the most threatened ecosystems in the world. Spatial prioritization of high quality habitat in agricultural landscapes is needed to protect grassland biodiversity. Within this context, we focused on European ground squirrel, a keystone species in steppe and salt steppe ecosystems. Using historical data and habitat field mapping, this study evaluates species distribution and site occupancy along the southern margin of the species range (Serbia) and identifies priority conservation zones in an intensively used landscape. Using gap analysis to evaluate changes in distribution over time and land protection status of the occupied area, we found that the regional species range has been constricted by 70%, and that 43% of mapped areas were outside of conservation networks. We also used a landscape structure model and multivariate analysis to identify the effects of spatial heterogeneity on occupancy. After mapping potential conservation zones with a buffer radius of 4.6 km—the scale with significant effects on occupancy—we identified 19 potential agro-ecological zones that cover the full range of mapped species habitats. The proposed agro-ecological zones differ in percentage of occupancy, which was found to increase with the overall landscape heterogeneity. This study contributes to the ongoing effort to broaden the understanding of the ecology and conservation of the European ground squirrel and the grasslands they rely on. Conservation planning should be designed to protect grasslands occupied by ground squirrels, ensure that the agricultural matrix is permeable, and to sustain or enhance landscape heterogeneity.
T2  - Biodiversity and Conservation
T1  - Landscape heterogeneity effects on keystone rodent species: agro-ecological zoning for conservation of open grasslands
DO  - 10.1007/s10531-019-01810-y
ER  - 

@article{
author = "Nikolić, Tijana and Radišić, Dimitrije and Ćosić, Nada and Díaz-Delgado, Ricardo and Milić, Dubravka and Vujić, Ante and Ćirović, Duško",
year = "2019",
abstract = "Grasslands are one of the most threatened ecosystems in the world. Spatial prioritization of high quality habitat in agricultural landscapes is needed to protect grassland biodiversity. Within this context, we focused on European ground squirrel, a keystone species in steppe and salt steppe ecosystems. Using historical data and habitat field mapping, this study evaluates species distribution and site occupancy along the southern margin of the species range (Serbia) and identifies priority conservation zones in an intensively used landscape. Using gap analysis to evaluate changes in distribution over time and land protection status of the occupied area, we found that the regional species range has been constricted by 70%, and that 43% of mapped areas were outside of conservation networks. We also used a landscape structure model and multivariate analysis to identify the effects of spatial heterogeneity on occupancy. After mapping potential conservation zones with a buffer radius of 4.6 km—the scale with significant effects on occupancy—we identified 19 potential agro-ecological zones that cover the full range of mapped species habitats. The proposed agro-ecological zones differ in percentage of occupancy, which was found to increase with the overall landscape heterogeneity. This study contributes to the ongoing effort to broaden the understanding of the ecology and conservation of the European ground squirrel and the grasslands they rely on. Conservation planning should be designed to protect grasslands occupied by ground squirrels, ensure that the agricultural matrix is permeable, and to sustain or enhance landscape heterogeneity.",
journal = "Biodiversity and Conservation",
title = "Landscape heterogeneity effects on keystone rodent species: agro-ecological zoning for conservation of open grasslands",
doi = "10.1007/s10531-019-01810-y"
}

Nikolić, T., Radišić, D., Ćosić, N., Díaz-Delgado, R., Milić, D., Vujić, A.,& Ćirović, D.. (2019). Landscape heterogeneity effects on keystone rodent species: agro-ecological zoning for conservation of open grasslands. in Biodiversity and Conservation.
https://doi.org/10.1007/s10531-019-01810-y

Nikolić T, Radišić D, Ćosić N, Díaz-Delgado R, Milić D, Vujić A, Ćirović D. Landscape heterogeneity effects on keystone rodent species: agro-ecological zoning for conservation of open grasslands. in Biodiversity and Conservation. 2019;.
doi:10.1007/s10531-019-01810-y .

Nikolić, Tijana, Radišić, Dimitrije, Ćosić, Nada, Díaz-Delgado, Ricardo, Milić, Dubravka, Vujić, Ante, Ćirović, Duško, "Landscape heterogeneity effects on keystone rodent species: agro-ecological zoning for conservation of open grasslands" in Biodiversity and Conservation (2019),
https://doi.org/10.1007/s10531-019-01810-y . .