scholarly journals Using historical dip net data to infer absence of flatwoods salamanders in stochastic environments

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12388
Author(s):  
George C. Brooks ◽  
Carola A. Haas
Keyword(s):  
Environmental Conditions ◽  
Landscape Connectivity ◽  
Breeding Population ◽  
Environmental Stochasticity ◽  
Stochastic Environments ◽  
Annual Variability ◽  
Biological Phenomena ◽  
Ambystoma Bishopi ◽  
Degree Of Certainty ◽  
A Site

Local extinction and undetected presence are two very different biological phenomena, but they can be challenging to differentiate. Stochastic environments hamper the development of standardized monitoring schemes for wildlife, and make it more challenging to plan and evaluate the success of conservation efforts. To avoid reintroductions of species at risk that could jeopardize extant populations, managers attempting translocation events require a higher level of confidence that a failure to confirm presence represents a true absence. For many pond breeding amphibians, monitoring of the breeding population occurs indirectly through larval surveys. Larval development and successful recruitment only occurs after a sequence of appropriate environmental conditions, thus it is possible for a breeding population of adults to exist at a site but for detectability of the species to be functionally zero. We investigate how annual variability in detection influences long-term monitoring efforts of Reticulated Flatwoods Salamanders (Ambystoma bishopi) breeding in 29 wetlands in Florida. Using 8 years of historic dip net data, we simulate plausible monitoring scenarios that incorporate environmental stochasticity into estimates of detection probability. We found that annual variation in environmental conditions precluded a high degree of certainty in predicting site status for low-intensity monitoring schemes. Uncertainty was partly alleviated by increasing survey effort, but even at the highest level of sampling intensity assessed, multiple years of monitoring are required to confidently determine presence/absence at a site. Combined with assessments of habitat quality and landscape connectivity, our results can be used to identify sites suitable for reintroduction efforts. Our methodologies can be generally applied to increase the effectiveness of surveys for diverse organisms for which annual variability in detectability is known.

scholarly journals Mapping landscape connectivity as a driver of species richness under tectonic and climatic forcing

2019 ◽  
Vol 7 (4) ◽  
pp. 895-910 ◽  
Author(s):  
Tristan Salles ◽  
Patrice Rey ◽  
Enrico Bertuzzo
Keyword(s):  
Species Richness ◽  
Landscape Connectivity ◽  
Tectonic Activity ◽  
Climatic Forcing ◽  
Mountainous Regions ◽  
Local Species Richness ◽  
Complex Interactions ◽  
Local Species ◽  
Elevational Range ◽  
A Site

Abstract. Species distribution and richness ultimately result from complex interactions between biological, physical, and environmental factors. It has been recently shown for a static natural landscape that the elevational connectivity, which measures the proximity of a site to others with similar habitats, is a key physical driver of local species richness. Here we examine changes in elevational connectivity during mountain building using a landscape evolution model. We find that under uniform tectonic and variable climatic forcing, connectivity peaks at mid-elevations when the landscape reaches its geomorphic steady state and that the orographic effect on geomorphic evolution tends to favour lower connectivity on leeward-facing catchments. Statistical comparisons between connectivity distribution and results from a metacommunity model confirm that to the 1st order, landscape elevation connectivity explains species richness in simulated mountainous regions. Our results also predict that low-connectivity areas which favour isolation, a driver for in situ speciation, are distributed across the entire elevational range for simulated orogenic cycles. Adjustments of catchment morphology after the cessation of tectonic activity should reduce speciation by decreasing the number of isolated regions.

scholarly journals Estimating probabilistic dark diversity based on the hypergeometric distribution

2019 ◽  
Author(s):  
Carlos P. Carmona ◽  
Robert Szava-Kovats ◽  
Meelis Pärtel
Keyword(s):  
Hypergeometric Distribution ◽  
Data Availability ◽  
Present Species ◽  
List Type ◽  
Species Frequency ◽  
Ecological Information ◽  
Degree Of Certainty ◽  
Species Membership ◽  
A Site ◽  
Best Estimator

AbstractThe biodiversity of a site includes the absent species from the region that are theoretically able to live in the site’s particular ecological conditions. These species constitute the dark diversity of the site. Unlike present species, dark diversity is unobservable and can only be estimated. Most existing methods to designate dark diversity act in a binary fashion. However, dark diversity is more suitably defined as a fuzzy set—in which the degree of certainty about species membership is expressed as a probability.We present a new method to estimate probabilistic dark diversity based on the hypergeometric distribution. The method relies on co-occurrences to infer the strength of the association between pairs of species and assign probabilistic adscription to dark diversity to absent species. We compare it with two established methods to estimate dark diversity (Beals index and favorability correction). To test the methods, we created simulations based on individual agents in which the suitability of each species in each site is known. We compared the ability of the methods to accurately predict suitability and the size of dark diversity, and compared their sensitivity to data availability. Further, we assessed the methods in two real datasets with nested sampling designs.Our simulations revealed that predictions of the Beals method were extremely sensitive to species frequency, and predicted suitability poorly. The Favorability transformation corrected this relationship, but did still predicted extremely low probabilities for species with very little information. The Hypergeometric method outperformed the Beals and Favorability methods in all considered aspects in the simulations and displayed better characteristics in the real datasets.Probabilistic consideratiosn of biodiversity will help to acknowledge the uncertainty associated with ecological information. Although the Beals method has been described as the best estimator of dark diversity, it should be preferred only when the goal is to predict future apperances of species. However, studies on dark diversity should focus on the ecological affinities of species. The Hypergeometric method is the most promising method to estimate probabilistic dark diversity and species pool composition based on co-occurrences.

scholarly journals Patterns of Temporal and Spatial Variability of Sponge Assemblages

2021 ◽  
Author(s):  
◽  
Jade Berman
Keyword(s):  
New Zealand ◽  
Environmental Conditions ◽  
South Coast ◽  
Spatial And Temporal Variability ◽  
Taxonomic Distinctness ◽  
Monitoring Methods ◽  
Data Set ◽  
Significant Group ◽  
Temporal Factors ◽  
A Site

<p>The primary goals of this thesis were to understand the spatial and temporal pattern of sponge assemblage variation over a variety of scales and investigate suitable monitoring methods for sponge assemblages. Sponges are an ecologically significant group in benthic marine communities, which are often ignored in current monitoring schemes. In chapter two the sponge biodiversity of New Zealand waters to 200m was examined using Taxonomic Distinctness measures initially to test if genera data could be used as a proxy for species level data in New Zealand waters. It was found that over 50% of the variation in genera biodiversity could be explained by location and depth around New Zealand. The study helped pinpoint where there were gaps in the New Zealand dataset, in particular for the West Coast of the South Island and also areas such as the Wellington South Coast, which had higher than expected values for Average and Variation Taxonomic distinctness measures, which as important areas where sponges should be monitored to make sure the high levels of biodiversity are protected. Taxonomic distinctness measures are useful for initially assessing how the biodiversity is distributed, especially when using a data set with uneven sampling effort, as it is robust to spatial and temporal bias in the majority of cases. However, there was an outlier to the genera data correlating well with the variation in species data in the case of a site dominated by Haliclona sp (Lyttelton Harbour). In chapters three and four the spatial and temporal variability of sponge assemblages of the Wellington South Coast were explored creating both a species list for the area and an understanding of how the sponge assemblage varies over time and space. There were significant differences in the sponges assemblages in similar habitat types over a scale of a few hundred metres. In addition, although all the sponge assemblages changed seasonally, the changes at each sampling site responded in a slightly different way most likely due to spatiotemporal variation in environmental conditions. A similar seasonal pattern was also observed in chapter five for sponge assemblages at Skomer Marine Reserve and this pattern was also clear when using morphological monitoring methods. This means that once a site has been mapped for biodiversity it is possible for some habitats to use morphological monitoring to identify if the sponge assemblage is changing significantly saving time and money. The results from Indonesia (chapter six) showed that although the sponge assemblages were changing significantly in the actual species present and their abundances, the proportion of diversity within each spatial level (quadrat, site and region) remained consistent when sampled at the same time each year throughout the five year study. In species rich assemblages there are a variety of life strategies that can respond differently to shifts in environmental conditions and contribute to ecological functioning in various ways. Various monitoring methods have been tested using sponge assemblages over various spatial and temporal scales in this thesis. Spatial, temporal and the interaction of spatial and temporal factors were all important for identifying significant assemblage differences at all of the sites. Further studies integrating the interaction of spatial and temporal factors into understanding monitoring data sets are vital to understand the patterns of assemblage variability and therefore incorporate into habitat management plans.</p>

scholarly journals Mapping landscape connectivity under tectonic and climatic forcing

2019 ◽  
Author(s):  
Tristan Salles ◽  
Patrice Rey ◽  
Enrico Bertuzzo
Keyword(s):  
Species Richness ◽  
Landscape Connectivity ◽  
Tectonic Activity ◽  
Climatic Forcing ◽  
Mountainous Regions ◽  
Local Species Richness ◽  
Complex Interactions ◽  
Local Species ◽  
Elevational Range ◽  
A Site

Abstract. Species distribution and richness ultimately result from complex interactions between biological, physical and environmental factors. It has been recently shown for a static natural landscape that the elevational connectivity, which measures the proximity of a site to others with similar habitats, is a key physical driver of local species richness. Here we examine changes in elevational connectivity during mountain building using a landscape evolution model. We find that under uniform tectonic and variable climatic forcing, connectivity peaks at mid-elevations when the landscape reaches its geomorphic steady-state and that orographic effect on geomorphic evolution tends to favour low connectivity on leeward facing catchments. Statistical comparisons between connectivity distribution and results from a metacommunity model confirm that landscape elevation connectivity explains to the first order species richness in simulated mountainous regions. Our results also predict that low connectivity areas which favour isolation, a driver for in-situ speciation, are distributed across the entire elevational range for simulated orogenic cycles. Rapid adjustments of catchment morphology after cessation of tectonic activity should reduce speciation by decreasing the number of isolated regions.

CRITICAL DENSITY IN A FIRE SPREAD MODEL UNDER ENVIRONMENTAL INFLUENCE

2003 ◽  
Vol 03 (02) ◽  
pp. 145-155 ◽  
Author(s):  
XIAODONG LI ◽  
WILLIAM MAGILL
Keyword(s):  
Environmental Conditions ◽  
Environmental Influence ◽  
Landscape Connectivity ◽  
Critical Density ◽  
Fire Spread ◽  
Tree Density ◽  
Artificial Environment ◽  
Spread Model ◽  
Multi Agent ◽  
Micro Level

Small changes in spatial pattern on a landscape can sometimes produce dramatic ecological responses. Such transition ranges are associated with critical environmental conditions such as tree density. As the landscape becomes dissected into smaller patches of trees, landscape connectivity may suddenly become disrupted, which may have important consequences for the behaviours of forest fire, i.e. how it spreads. Landscape connectivity depends not only on the tree density but also many other environmental conditions such as land height, flammability, and wind conditions. To determine how the critical densities are affected by the changes in these conditions, we developed a fire spread simulation model using a multi-agent (i.e. bottom-up) approach. This model simulates an artificial environment where bush is randomly generated and fire can be ignited and then spread across the environment according to some "interaction rules". The emergent fire spread behaviours at the landscape level are determined by such micro-level "interaction rules". This model takes into account some major environmental factors that influence fire growth. By varying these variables under controlled conditions, this research aims to show how varied environmental conditions affect the critical density, and hence influence the spread and growth of fire.

scholarly journals Patterns of Temporal and Spatial Variability of Sponge Assemblages

2021 ◽  
Author(s):  
◽  
Jade Berman
Keyword(s):  
New Zealand ◽  
Environmental Conditions ◽  
South Coast ◽  
Spatial And Temporal Variability ◽  
Taxonomic Distinctness ◽  
Monitoring Methods ◽  
Data Set ◽  
Significant Group ◽  
Temporal Factors ◽  
A Site

<p>The primary goals of this thesis were to understand the spatial and temporal pattern of sponge assemblage variation over a variety of scales and investigate suitable monitoring methods for sponge assemblages. Sponges are an ecologically significant group in benthic marine communities, which are often ignored in current monitoring schemes. In chapter two the sponge biodiversity of New Zealand waters to 200m was examined using Taxonomic Distinctness measures initially to test if genera data could be used as a proxy for species level data in New Zealand waters. It was found that over 50% of the variation in genera biodiversity could be explained by location and depth around New Zealand. The study helped pinpoint where there were gaps in the New Zealand dataset, in particular for the West Coast of the South Island and also areas such as the Wellington South Coast, which had higher than expected values for Average and Variation Taxonomic distinctness measures, which as important areas where sponges should be monitored to make sure the high levels of biodiversity are protected. Taxonomic distinctness measures are useful for initially assessing how the biodiversity is distributed, especially when using a data set with uneven sampling effort, as it is robust to spatial and temporal bias in the majority of cases. However, there was an outlier to the genera data correlating well with the variation in species data in the case of a site dominated by Haliclona sp (Lyttelton Harbour). In chapters three and four the spatial and temporal variability of sponge assemblages of the Wellington South Coast were explored creating both a species list for the area and an understanding of how the sponge assemblage varies over time and space. There were significant differences in the sponges assemblages in similar habitat types over a scale of a few hundred metres. In addition, although all the sponge assemblages changed seasonally, the changes at each sampling site responded in a slightly different way most likely due to spatiotemporal variation in environmental conditions. A similar seasonal pattern was also observed in chapter five for sponge assemblages at Skomer Marine Reserve and this pattern was also clear when using morphological monitoring methods. This means that once a site has been mapped for biodiversity it is possible for some habitats to use morphological monitoring to identify if the sponge assemblage is changing significantly saving time and money. The results from Indonesia (chapter six) showed that although the sponge assemblages were changing significantly in the actual species present and their abundances, the proportion of diversity within each spatial level (quadrat, site and region) remained consistent when sampled at the same time each year throughout the five year study. In species rich assemblages there are a variety of life strategies that can respond differently to shifts in environmental conditions and contribute to ecological functioning in various ways. Various monitoring methods have been tested using sponge assemblages over various spatial and temporal scales in this thesis. Spatial, temporal and the interaction of spatial and temporal factors were all important for identifying significant assemblage differences at all of the sites. Further studies integrating the interaction of spatial and temporal factors into understanding monitoring data sets are vital to understand the patterns of assemblage variability and therefore incorporate into habitat management plans.</p>

scholarly journals Optimizing the power of human performed audio surveys for monitoring the endangered Houston toad using automated recording devices

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11935
Author(s):  
Andrew R. MacLaren ◽  
Paul S. Crump ◽  
Michael R.J. Forstner
Keyword(s):  
Land Use ◽  
Land Use Planning ◽  
Environmental Conditions ◽  
Detection Probability ◽  
Probability Of Detection ◽  
Regulatory Agencies ◽  
Critical Part ◽  
Houston Toad ◽  
A Site ◽  
Survey Effort

Knowledge regarding the locations of populations of endangered species is a critical part of recovery and facilitates land use planning that avoids unnecessary impacts. Regulatory agencies often support the development of survey guidelines designed to standardize the methods and maximize the probability of detection, thereby avoiding incorrectly concluding a species is absent from a site. Here, using simulations with data collected using automated recording devices (ARDs) we evaluated the efficacy of the existing U.S. Fish and Wildlife Service’s survey requirements for the endangered Houston Toad (Anaxyrus houstonensis). We explored the effect of (1) increasing survey duration, (2) increasing the number of surveys, and (3) combinations of environmental conditions (e.g., temperature, humidity, rainfall) on the detection probability and the number of surveys needed to be 95% confident of absence. We found that increases in both the duration of the survey and the number of surveys conducted decreased the likelihood of incorrectly concluding the species was absent from the site, and that the number of surveys required to be 95% confident greatly exceeded the existing survey requirements. Targeting specific environmental conditions was also an effective way to decrease the number of surveys required but the infrequency in which these conditions occurred might make application difficult in some years. Overall, we suggest that the survey effort necessary to achieve confidence in the absence of Houston Toads at a site is more practically achievable with the use of ARDs, but this may not be suitable in all monitoring scenarios.

scholarly journals Ecological and morphological characteristics of pyramidal fir (Abies alba var. pyramidalis) in the locality of Ogorijevac (the Pester plateau)

2013 ◽  
Vol 65 (4) ◽  
pp. 1609-1617
Author(s):  
M. Ratknic ◽  
Lj. Rakonjac ◽  
Sonja Braunovic ◽  
Snezana Stajic ◽  
A. Lucic ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Morphological Characteristics ◽  
Abies Alba ◽  
Parent Rock ◽  
Individual Trees ◽  
A Site ◽  
The Town ◽  
Soil Climate

The paper presents environmental conditions and morphological characteristics of pyramidal fir (Abies alba var. pyramidalis) in the locality of Ogorijevac in southwestern Serbia. Pyramidal fir trees grow in three localities in Europe, but only as individual trees. A site of pyramidal fir (Abies alba var. pyramidalis) in the locality of Ogorijevac near the town of Sjenica in Serbia was first studied by Tosic in 1963, who described some characteristics of the locality in which the pyramidal fir occurs and some morphological characteristics of the trees. This paper provides a detailed description of the parent rock, soil, climate characteristics of the locality and morphological characteristics of the trees.

Comparison of winter-active phalaris with the Australian cultivar under rotational grazing. 2. Dry matter on offer, pasture composition and animal production

1996 ◽  
Vol 36 (3) ◽  
pp. 287 ◽  
Author(s):  
RA Culvenor ◽  
JT Wood ◽  
RN Oram
Keyword(s):  
Basal Area ◽  
Breeding Population ◽  
Animal Production ◽  
Rotational Grazing ◽  
Second Year ◽  
A Site ◽  
Tiller Density ◽  
Autumn And Winter ◽  
Made In

Composition and amount of pasture on offer and animal productivity are presented from an experiment in which 2 'winter-active' cultivars (Sirosa, Holdfast) and a breeding population (Perla Retainer) of phalaris (Phalaris aquatica L.) bred for rapid growth in autumn and winter were compared with the original cultivar, Australian, under rotational grazing at 15 wethersfha for 3 years at 2 sites near Canberra. A change of cultivar rank in phalaris herbage on offer occurred in winter of the second year, whereby Australian became the highest ranked cultivar, reflecting its 50-70% higher basal area and 70% higher tiller density. However, pastures of the winter-active lines had an average 30% more phalaris on offer per unit basal area and per tiller, and a larger component of other, mainly annual, grass. This resulted in total pasture on offer at least equivalent to that of Australian pastures, and possibly more herbage production in autumn and winter. Sheep on the winter-active phalaris pastures were slightly heavier on average due mainly to higher weight gains in the first half of the year. These sheep produced an average over both sites of 7% more wool than sheep on Australian pastures, the advantage being higher at a site with dense phalaris (10%, P<0.01) than at a site with shallow, coarse-textured soil and less phalaris (3.5%, P = 0.11). It was concluded that pastures of the winter-active phalaris lines can give higher wool production than pastures of Australian phalaris, but not necessarily because of higher amounts of phalaris in the pasture. Benefits in the long term would also depend on persistence. Breeders of phalaris should aim to increase yield per unit of basal area if animal production gains in the short term are to be made in this environment, but compromises may be necessary between productivity and long-term persistence.

Sign in / Sign up

Export Citation Format

Share Document