Sex structure and population growth rate of roe deer <em>Capreolus capreolus</em> and red deer <em>Cervus elaphus</em> in three landscapes estimated through cumulative direct observations

The aim of the study was to determine the sex structure and reproduction rate of roe deer <em>Capreolus capreolus</em> and red deer <em>Cervus elaphus</em> in six forest districts in north−western Poland: Choszczno, Dobrzany, Karwin, Międzychód, Barlinek and Kłodawa. The forest districts represent three different types of landscape: Field – an agricultural landscape in the north, consisting of a mosaic of large agricultural areas and small forest complexes; ConFor – a compact forest complex in the south, dominated by poor pine sites; and DecFor – consisting of dense, fertile forests in the central part of the study area. The study used a cumulative method of direct observation conducted in the field over a period of 20 days. The direct observations of the animals were car− ried out from July 23 to August 11 with the participation of employees of the State Forests, local hunters and volunteers. About 60 observers per day were present in the field area, 80 in the ConFor and 70 in the DecFor. The observations took place at different times of the day, with participants recording the individuals encountered and determining their sex and age. Only juveniles born in the current year (2−3 months old during the study) and adults were recorded, yearlings were excluded. A total of 8,817 animals were recorded during the observations, including 6,014 roe deer and 2,803 red deer. The highest number of individuals was observed in the Field landscape (5,734), where open terrain facilitated observation, while significantly fewer animals were recorded in ConFor (1,429) and DecFor (1,654). No significant differences in sex structure and reproductive rate were observed between the three environmental types. The sex ratio averaged 1 : 1 ; however, in some cases the number of females exceeded the number of males. The reproductive rate was about 0.6 young per female. The sex structure of the local popula− tions varied from area to area – in the Field landscape, for example, the ratio of females to males was 1.34 for roe deer and 1.02 for red deer. The reproduction rate for roe deer ranged from 0.35 young per female in DecFor to 0.51 in Field. For red deer, the reproduction rate ranged from 0.54 in Field to 0.60 in ConFor, showing significant statistical differences. One of the effects of aggregating observations was to stabilize the results for sex structure and reproductive rate as the number of animals observed increased. In the Field landscape, results stabilized at ±5% after only a few days of observation, whereas this took longer in ConFor and DecFor due to the more difficult observation conditions in the forest. The method of aggregating results from direct observations can be useful as a research tool and for population management but requires further theoretical and practical research.