Using geoestatistics for assessing biodiversity of forest reserve areas

Abstract

Protecting natural mosaics as forest reserves poses a challenge, because if they hold significant high levels of biodiversity, they may function as key seed sources for regenerating ecosystems and adjacent reforested areas. Currently, there is lack of information about the spatial organization of native species in core forest fragments remaining between reforested fields. Biodiversity as measured by species and number of individuals was assessed in two forest reserve zones located within reforestations of Eucalyptus sp and Pinus sp in Agudos, São Paulo, Brazil. The main objective was to compare the state of biodiversity within two natural areas with contrasting disturbance levels; a second objective was to investigate recognisable patterns of species and individuals spatial distribution. A grid-like set of plots was set up for data collection over each of the two study areas. Natural species were aggregated onto two groups using height classes, inferior level (< 0.5 m) and superior level (> 1.3 m) layers. Within each natural area the number of species and individuals of the height class > 1.3 m was counted on 50 square plots of 100 m 2 (10 x 10 m) whereas those of the height class < 0.5 m were counted on 250 subplots of 1 m 2 (1 x 1 m). Data analysis involved both statistical and geostatistical methods. Experimental semivariograms of number of species and individuals were modelled by a nugget component plus a spherical structure with autocorrelation ranging from approximately 20 to 60 m. Cross-semivariograms could also be computed and modelled in some cases. Nugget effects of both species and individual's count for inferior level were shown to be larger for small sized plots, whereas the spatially structured component increased as the plot size increased. Individual's count showed a higher continuity at close distances than species number in the superior level (> 1.3 m), and the reverse was true for the inferior level (< 0.5 m). Usefulness of kriging maps for comparing patterns of spatial variation between the two studied natural mosaics has been illustrated.Key words: nugget effect, kriging, semiovariograms. RESUMO USO DE GEOESTATISTICA PARA AVALIAR A BIODIVERSIDADE DE RESERVAS NATURAISA proteção de fragmentos naturais dentro de áreas reflorestadas é importante por ser um banco de sementes e possuir espécies-chave de significância à biodiversidade, tornando-se um desafio para a pesquisa, pois colabora com a regeneração de ecossistemas e de áreas reflorestadas adjacentes. Atualmente, existe pouca informação sobre a organização espacial das espécies nativas nos fragmentos florestais remanescentes dentro de áreas reflorestadas. Assim, a biodiversidade foi avaliada por meio da ocorrência de espécie e do número de indivíduos em dois fragmentos de mata nativa situados dentro de reflorestamentos de Eucalyptus sp. e de Pinus sp. em Agudos, São Paulo, Brasil. O objetivo principal deste trabalho foi comparar a condição da biodiversidade dentro dos dois fragmentos naturais com níveis distintos de perturbação, e ta...

Influência da floresta alterada na distribuição espacial de três espécies da Floresta Ombrófila Mista avaliada pela geoestatística

“…Mattos) sob duas formas de manejo, e as estruturas de continuidade espacial em quatro formações florestais no Estado de São Paulo (USHIZIMA et al, 2003;KLEIN et al, 2007;ODA-SOUZA et al, 2010). Já Neves et al (2010) utilizaram a geoestatística para avaliar a biodiversidade da regeneração em áreas de remanescentes em meio a plantios de Pinus sp. e Eucalyptus sp.…”

Relationship scales of soil arthropods and vegetation structure of Cerrado phytophysiognomies

“…The spatial variability of most of the variables under study fitted to the spherical model (Table 3), whereas the abundance of arthropods and tree plants in T1 and DBH (1.3 m) 2018) stated that the pure nugget effect describes the spatial variability occurring at distances smaller than the spacing used, or homogeneity of measurements, according to Neves et al (2010).…”

“…The vegetation structure was evaluated in subplots of 9 m 2 , with the soil invertebrate fauna sampling point as the centroid. The number of plants of different heights was determined: <0.5 m (herbaceous stratum), between 0.5 and 1.3 m (arborescent stratum), and >1.3 m (tree stratum), where the average DBH (in meters; tree stratum) was also determined, according to Neves et al (2010).…”

“…Gholami et al (2017) used geostatistics to characterize the spatial distribution of tree species and soil arthropods, and Silva et al (2018) assessed the spatial variability of soil fauna in different land use and occupation systems. Neves et al (2010) studied the scales of spatial variability of Cerrado fragments to show that the plant strata had different scales of spatial distribution.…”

Spatial and temporal distribution of species diversity in semideciduous seasonal forests with occurrence of fire

“…Geostatistics can be used to represent the spatial distributions of environmental factors and examine the ecological aspects of recovery and these tools have been used by numerous researchers to examine the spatial dependence of forest components (Rufino, Thiersch, Ferreira, Kanegae-Junior, & Fais, 2006;Amaral, Ferreira, Watzlawick, & Genú, 2010;Neves, Lemos, Gonzáles, Vieira, & Siqueira, 2010;Amaral, Ferreira, Lisboa, Longhi, & Watzlawick, 2013a). These studies can help generate a better understanding of the establishment and reproduction of individuals (Condit et al, 2000), the maintenance of species diversity, succession, evolution, and adaptations (Legendre & Fortin, 1989), and optimize techniques for sustainable forest management, and sampling and monitoring of plant species (Pereira, Péllico-Netto, & Carvalho, 2006).…”