Effect of watershed land use and lake age on zooplankton species richness

Hydrobiologia ◽  
2006 ◽  
Vol 579 (1) ◽  
pp. 393-399 ◽  
Author(s):  
Stanley I. Dodson ◽  
William R. Everhart ◽  
Andrew K. Jandl ◽  
Sara J. Krauskopf
2002 ◽  
Vol 59 (2) ◽  
pp. 310-316 ◽  
Author(s):  
Kelly E Arbuckle ◽  
John A Downing

We tested the hypotheses that mussel species richness and density are related to landscape features of watersheds. Measures of species richness and mussel density were estimated at 118 sites in 36 watersheds in the state of Iowa, U.S.A., a landscape characterized by >90% agricultural development. Geographical Information Systems (GIS) and regression analyses examined seven land use categories and nine geological descriptors, determining that both mean density and species richness were best correlated with mean watershed slope and the prevalence of alluvial deposits. Our analyses imply that agricultural watersheds with high slopes impact mussel abundance and richness through siltation and destabilization of stream substrate. Because alluvial deposits improve groundwater flux to streams, results suggest that relatively stable stream flows in alluvial watersheds improve mussel persistence. A second set of 82 observations on 38 independent watersheds corroborates the analyses, although historical and local impacts cause correlations between new observations and predictions to be weak.


Weed Science ◽  
2007 ◽  
Vol 55 (2) ◽  
pp. 129-136 ◽  
Author(s):  
Lynn M. Sosnoskie ◽  
Edward C. Luschei ◽  
Mark A. Fanning

The importance of managing weeds in seminatural habitats that are adjacent to farm fields is unclear. Weedy-margin vegetation may harbor pests or pathogens and may ALSo serve as source populations for ongoing immigration of weeds into the field. It is ALSo possible, however, that margin vegetation provides habitat for organisms that consume weed seeds or suppress the likelihood of pest or pathogen outbreak. We examined the nature of margin habitat using spatial-scaling of Weed-Species richness as an ecological assay. In 2003, we recorded the occurrence of weedy species along the perimeters of 63 fields in Wisconsin. The fields were distributed within six counties that differed in topography, geological history, local climate, and soil type and which spanned the range of variability in the agricultural landscape. We identified seven habitats that differed in geology and land use. The relationship between species richness and margin class was estimated using an analog of the power law. Additionally, we investigated broadscale correlates of habitat heterogeneity at the field level, using a modeling strategy that included additional explanatory factors logically connected to plant diversity. Using a model-confrontation approach, the survey supported the inclusion of two topographical diversity indices, elevation gradient and a field-shape index, into our model. Our broadscale survey provides information on one of a suite of important considerations needed to make decisions about the importance of managing weeds in field margins.


2011 ◽  
Vol 41 (8) ◽  
pp. 1687-1697 ◽  
Author(s):  
Lee Jacobs ◽  
Jeff E. Houlahan

Here, we examine the effects of adjacent land use in a managed forest on pond-breeding amphibian species richness and community composition at 34 New Brunswick, Canada, ponds. Amphibian species richness was negatively correlated with the proportion of roads, precommercial thinning, and hardwood forest and positively correlated with the proportion of wetlands in adjacent lands. These land-use effects peak at 180 m from the ponds. Road density was negatively correlated with Lithobates catesbeiana and Lithobates septentrionalis presence. Precommercial thinning was negatively correlated with Ambystoma spp. presence and positively correlated with Anaxyrus americanus presence. Wetlands were positively correlated with L. septentrionalis and Notopthalamus viridescens presence. Correlations were also found between water table height and A. americanus, Lithobates palustris , and Ambystoma spp. presence. In addition, L. catesbeiana and N. viridescens presence–absence was positively correlated with the proportion of mature and overmature forest on the landscape (at scales of 500 and 1000 m, respectively). Lastly, the proportion of regenerating and sapling forest on the landscape was negatively correlated with L. palustris presence–absence but, by contrast, was positively correlated with A. americanus. These results suggest that the effects of adjacent land use may significantly impact amphibian populations in managed eastern Canadian forests.


2018 ◽  
Vol 11 (2) ◽  
pp. 78-84 ◽  
Author(s):  
Agno Nonato Serrão Acioli

Resumo. Os cupins são importantes decompositores da matéria de origem vegetal. Este estudo teve como objetivo analisar e comparar a diversidade e composição das espécies de cupins em três diferentes sistemas de uso do solo na região do Alto Solimões, Amazonas, Brasil. Os cupins foram coletados na floresta primária, em cultivos de dendê (Elaeis guineensis Jacq.) e mandioca (Manihot sculenta Crantz). Em cada área selecionada as coletas foram realizadas dentro de um transecto retangular medindo 100 m x 2 m, subdivididos em 20 parcelas de 5 m x 2 m. Foram encontradas 24 espécies de cupins, pertencentes a 14 gêneros e duas famílias, nos três sistemas de uso do solo. As espécies mais frequentes foram Nasutitermes cf. dendrophilus (Desneux) (28,43%), seguida de Heterotermes tenuis (Hagen) (14,37%) e Anoplotermes sp. 2 (9,58%). A riqueza de espécies foi maior na floresta primária (16 espécies), seguida dos cultivos de dendê (14 espécies) e mandioca (seis espécies). A composição taxonômica e os grupos funcionais também sofreram modificações, sendo mais diversificados e equilibrados na floresta primária quando comparados com os dois tipos de cultivos. A comunidade de cupins é fortemente afetada quando ocorre a substituição da floresta primária pelos cultivos agrícolas. Neste estudo, as espécies N. cf. dendrophilus e H. tenuis merecem atenção, pois se constata o aumento de sua frequência nos cultivos de dendê e mandioca.Frequency, Diversity and Composition of Termite Fauna (Blattodea: Isoptera) in Land Use Systems in the Southwest of Amazonas, Brazil Abstract. Termites are important decomposers of matter of vegetable origin. This study aims to analyze and compare the diversity and composition of termite species in three different land use systems in Alto Solimões, Amazonas, Brazil. Termites were collected in the primary forest, oil palm (Elaeis guineensis Jacq.) and cassava (Manihot sculenta Crantz) crops. In each area the collections were made within a rectangular transect measuring 100 m x 2 m, subdivided into 20 plots of 5 m x 2 m. Twenty four species of termites were found, belonging to 14 genera and two families. The most frequent species were Nasutitermes cf. dendrophilus (Desneux) (28.43%), Heterotermes tenuis (Hagen) (14.37%) and Anoplotermes sp. 2 (9.58%). The species richness was higher in the primary forest (16 species), followed by oil palm (14 species) and cassava (six species) crops. The taxonomic composition and the functional groups were also modified, being more diversified and balanced in the primary forest than in the crops. The termite community was strongly affected when the primary forest was replaced by agricultural crops. The species N. cf. dendrophilus and H. tenuis deserve attention, it was verified the increase of their frequency in the crops.


2021 ◽  
Vol 933 (1) ◽  
pp. 012010
Author(s):  
S A Nurhayati ◽  
M Marselina ◽  
A Sabar

Abstract Increasing population growth is one of the impacts of the growth of a city or district in an area. This also happened in the Cimahi watershed area. As the population grows, so does the need for land which increases the land-use change in the Cimahi watershed. Land-use changes will affect the surrounding environment and one of them is the river, especially river water quality. As a watershed area, there is one main river that is the source of life as well as the Cimahi watershed, whose main river is the Cimahi River. The purpose of this study was calculated the relationship between land-use change in the Cimahi watershed and the water quality parameters of the Cimahi River. The correlation between the two was calculated using Pearson correlation. Water quality parameters can be seen based on BOD and DO values. BOD and DO values are the opposite because good water quality has high DO values and low BOD values. The correlation between land-use change and BOD was 0.328 is in the area of settlements area. In contrast, to DO values, an increase in settlements/industrial zones will further reduce DO values so that both have a negative correlation, which is indicated by a value of -0,535. The correlation between settlements with pH and temperature values is 0.664 and 0.812. While the correlation between settlements with TSS and TDS values are 0.333 and 0.529, respectively. In this study, it can be seen that there is a relationship between the decline in water quality and changes in land use.


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