scholarly journals Optimizing speleological monitoring efforts: insights from long-term data for tropical iron caves

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11271
Author(s):  
Leonardo Carreira Trevelin ◽  
Matheus Henrique Simões ◽  
Xavier Prous ◽  
Thadeu Pietrobon ◽  
Iuri Viana Brandi ◽  
...  
Keyword(s):  
Species Abundance ◽  
Dry Season ◽  
Target Species ◽  
Study Region ◽  
Monitoring Programs ◽  
Abundance Trends ◽  
Conservation Actions ◽  
Cave Monitoring ◽  
Temporal Abundance

Understanding the factors underpinning species abundance patterns in space and time is essential to implement effective cave conservation actions. Yet, the methods employed to monitor cave biodiversity still lack standardization, and no quantitative assessment has yet tried to optimize the amount and type of information required to efficiently identify disturbances in cave ecosystems. Using a comprehensive monitoring dataset for tropical iron caves, comprising abundance measurements for 33 target taxa surveyed across 95 caves along four years, here we provide the first evidence-based recommendations to optimize monitoring programs seeking to follow target species abundance through time. We found that seasonality did not influence the ability to detect temporal abundance trends. However, in most species, abundance estimates assessed during the dry season resulted in a more accurate detection of temporal abundance trends, and at least three surveys were required to identify global temporal abundance trends. Finally, we identified a subset of species that could potentially serve as short-term disturbance indicators. Results suggest that iron cave monitoring programs implemented in our study region could focus sampling efforts in the dry season, where detectability of target species is higher, while assuring data collection for at least three years. More generally, our study reveals the importance of long-term cave monitoring programs for detecting possible disturbances in subterranean ecosystems, and for using the generated information to optimize future monitoring efforts.

scholarly journals Effects of habitat edges on vegetation structure and the vulnerable golden-brown mouse lemur (Microcebus ravelobensis) in northwestern Madagascar

BMC Ecology ◽  
2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Bertrand Andriatsitohaina ◽  
Daniel Romero-Mujalli ◽  
Malcolm S. Ramsay ◽  
Frederik Kiene ◽  
Solofonirina Rasoloharijaona ◽  
...  
Keyword(s):  
Body Mass ◽  
Edge Effects ◽  
Vegetation Structure ◽  
Species Abundance ◽  
Tree Height ◽  
Logistic Function ◽  
Study Region ◽  
Large Trees ◽  
Significant Difference ◽  
Vegetation Parameters

Abstract Background Edge effects can influence species composition and community structure as a result of changes in microenvironment and edaphic variables. We investigated effects of habitat edges on vegetation structure, abundance and body mass of one vulnerable Microcebus species in northwestern Madagascar. We trapped mouse lemurs along four 1000-m transects (total of 2424 trap nights) that ran perpendicular to the forest edge. We installed 16 pairs of 20 m2 vegetation plots along each transect and measured nine vegetation parameters. To determine the responses of the vegetation and animals to an increasing distance to the edge, we tested the fit of four alternative mathematical functions (linear, power, logistic and unimodal) to the data and derived the depth of edge influence (DEI) for all parameters. Results Logistic and unimodal functions best explained edge responses of vegetation parameters, and the logistic function performed best for abundance and body mass of M. ravelobensis. The DEI varied between 50 m (no. of seedlings, no. of liana, dbh of large trees [dbh ≥ 10 cm]) and 460 m (tree height of large trees) for the vegetation parameters, whereas it was 340 m for M. ravelobensis abundance and 390 m for body mass, corresponding best to the DEI of small tree [dbh < 10 cm] density (360 m). Small trees were significantly taller and the density of seedlings was higher in the interior than in the edge habitat. However, there was no significant difference in M. ravelobensis abundance and body mass between interior and edge habitats, suggesting that M. ravelobensis did not show a strong edge response in the study region. Finally, regression analyses revealed three negative (species abundance and three vegetation parameters) and two positive relationships (body mass and two vegetation parameters), suggesting an impact of vegetation structure on M. ravelobensis which may be partly independent of edge effects. Conclusions A comparison of our results with previous findings reveals that edge effects are variable in space in a small nocturnal primate from Madagascar. Such an ecological plasticity could be extremely relevant for mitigating species responses to habitat loss and anthropogenic disturbances.

Rising ecosystem water demand exacerbates the lengthening of tropical dry seasons

2021 ◽  
Author(s):  
Hao Xu ◽  
Xu Lian ◽  
Ingrid Slette ◽  
Hui Yang ◽  
Yuan Zhang ◽  
...  
Keyword(s):  
Water Demand ◽  
Potential Evapotranspiration ◽  
Central Africa ◽  
Dry Season ◽  
Land Area ◽  
Key Factor ◽  
Dry Seasons ◽  
The Tropics ◽  
Factor Governing

Abstract The timing and length of the dry season is a key factor governing ecosystem productivity and the carbon cycle of the tropics. Mounting evidence has suggested a lengthening of the dry season with ongoing climate change. However, this conclusion is largely based on changes in precipitation (P) compared to its long-term average (P ̅) and lacks consideration of the simultaneous changes in ecosystem water demand (measured by potential evapotranspiration, Ep, or actual evapotranspiration, E). Using several long-term (1979-2018) observational datasets, we compared changes in tropical dry season length (DSL) and timing (dry season arrival, DSA, and dry season end, DSE) among three common metrics used to define the dry season: P < P ̅, P < Ep, and P < E. We found that all three definitions show that dry seasons have lengthened in much of the tropics since 1979. Among the three definitions, P < E estimates the largest fraction (49.0%) of tropical land area likely experiencing longer dry seasons, followed by P < Ep (41.4%) and P < P ̅ (34.4%). The largest differences in multi-year mean DSL (> 120 days) among the three definitions occurred in the most arid and the most humid regions of the tropics. All definitions and datasets consistently showed longer dry seasons in southern Amazon (due to delayed DSE) and central Africa (due to both earlier DSA and delayed DSE). However, definitions that account for changing water demand estimated longer DSL extension over those two regions. These results indicate that warming-enhanced evapotranspiration exacerbates dry season lengthening and ecosystem water deficit. Thus, it is necessity to account for the evolving water demand of tropical ecosystems when characterizing changes in seasonal dry periods and ecosystem water deficits in an increasingly warmer and drier climate.

scholarly journals Minimum time required to detect population trends: the need for long-term monitoring programs

2018 ◽  
Author(s):  
Easton R White
Keyword(s):  
Time Series ◽  
Statistical Power ◽  
Conservation Status ◽  
Species Conservation ◽  
Population Data ◽  
Iucn Red List ◽  
Series Length ◽  
Large Variability ◽  
Monitoring Programs

Long-term time series are necessary to better understand population dynamics, assess species' conservation status, and make management decisions. However, population data are often expensive, requiring a lot of time and resources. What is the minimum population time series length required to detect significant trends in abundance? I first present an overview of the theory and past work that has tried to address this question. As a test of these approaches, I then examine 822 populations of vertebrate species. I show that 72% of time series required at least 10 years of continuous monitoring in order to achieve a high level of statistical power. However, the large variability between populations casts doubt on commonly used simple rules of thumb, like those employed by the IUCN Red List. I argue that statistical power needs to be considered more often in monitoring programs. Short time series are likely under-powered and potentially misleading.

Long-term declines in common breeding seabirds in Japan

2019 ◽  
Vol 30 (3) ◽  
pp. 434-446
Author(s):  
MASAYUKI SENZAKI ◽  
AKIRA TERUI ◽  
NAOKI TOMITA ◽  
FUMIO SATO ◽  
YOSHIHIRO FUKUDA ◽  
...  
Keyword(s):  
State Space Model ◽  
Common Species ◽  
Population Trends ◽  
Seabird Species ◽  
Common Murre ◽  
Cerorhinca Monocerata ◽  
Conservation Actions ◽  
Declining Species ◽  
The Japanese Archipelago

SummaryGlobal seabird populations are in decline, with nearly half of all seabird species currently in an extinction crisis. Understanding long-term seabird population trends is an essential first step to inform conservation actions. In this study, we assembled historical breeding records of seabirds throughout the Japanese archipelago and quantified the long-term population trends of 10 major breeding seabird species using a hierarchical Bayesian state-space model. The model revealed that six species had increasing or no detectable trends (Short-tailed Albatross Phoebastria albatrus, Leach’s Storm Petrel Oceanodroma leucorhoa, Pelagic Cormorant Phalacrocorax pelagicus, Japanese Cormorant Phalacrocorax capillatus, Spectacled Guillemot Cepphus carbo, and Rhinoceros Auklet Cerorhinca monocerata). However, decreasing trends were found not only in nationally threatened species (Common Murre Uria aalge, and Tufted Puffin Fratercula cirrhata) but also common species that are often described as abundant (Black-tailed Gull Larus crassirostris and Slaty-backed Gull Larus schistisagus). These declining species have declined to 3–35% of baseline levels over the past 30 years. This study provides the first evidence of long-term declines in common and widespread seabirds in Japan.

Convergence and divergence in a long-term old-field succession: the importance of spatial scale and species abundance

2016 ◽  
Vol 19 (9) ◽  
pp. 1101-1109 ◽  
Author(s):  
Shao-peng Li ◽  
Marc W. Cadotte ◽  
Scott J. Meiners ◽  
Zhichao Pu ◽  
Tadashi Fukami ◽  
...  
Keyword(s):  
Spatial Scale ◽  
Species Abundance ◽  
Old Field ◽  
Convergence And Divergence ◽  
Old Field Succession

scholarly journals The discontinuity of environmental effects monitoring in the Lower Athabasca region of Alberta, Canada: institutional challenges to long-term monitoring and cumulative effects management

2018 ◽  
Vol 26 (2) ◽  
pp. 169-180 ◽  
Author(s):  
Joshua G. Cronmiller ◽  
Bram F. Noble
Keyword(s):  
Decision Making ◽  
Environmental Monitoring ◽  
Environmental Effects ◽  
Regional Scale ◽  
Monitoring Program ◽  
Institutional Arrangements ◽  
Cumulative Effects ◽  
Regulatory Decision ◽  
Monitoring Programs

Long-term regional environmental monitoring, coupled with shorter-term and more localized monitoring carried out under regulatory permitting processes, is foundational to identifying, understanding, and effectively managing cumulative environmental effects. However, monitoring programs that emerge to support cumulative effects science are often short-lived initiatives or disconnected from land use planning and regulatory decision making. This paper examines the history and evolution of environmental monitoring in the Lower Athabasca region of Alberta, Canada, and the enabling and constraining influences of institutional arrangements. Methods involved a review of regional-scale monitoring programs based on an analysis of monitoring agency mandates, performance reports, and external program reviews, supplemented by discussions with monitoring program or agency key informants to triangulate results. Results show that monitoring to support cumulative effects understanding in the Lower Athabasca has advanced considerably, especially since the mid-1990s, but its relevance to, and impact on, cumulative effects management and decision making has been stifled by institutional arrangements. Monitoring has been episodic, reflecting shifting priorities and competing mandates; criticized by stakeholders based on concerns about transparency, credibility, influence over decision making; and characterized by short-lived commitments by the agencies involved. This has generated significant uncertainty about the stability of institutional arrangements to support long-term environmental monitoring, and tensions between the need for scientific autonomy for credible science whilst ensuring the pursuit of monitoring questions that are relevant to the day-to-day needs of regulatory decision makers. Regional monitoring programs require, at a minimum, clear vision and agreed-upon monitoring questions that are of scientific and management value, meaningful and balanced stakeholder engagement, and a clear governance process to ensure credibility and influence of monitoring results on decision making.

The longevity and efficacy of 1080 meat baits used for dingo control in central Australia

2000 ◽  
Vol 27 (5) ◽  
pp. 473 ◽  
Author(s):  
Laurie E. Twigg ◽  
Steve R. Eldridge ◽  
Glenn P. Edwards ◽  
Bernie J. Shakeshaft ◽  
Nicki D. dePreu ◽  
...  
Keyword(s):  
Water Bodies ◽  
Potential Hazard ◽  
Target Species ◽  
Term Survival ◽  
Control Programs ◽  
The Third ◽  
Central Australia ◽  
Considerable Period ◽  
Artificial Water

In central Australia, most 1080 (sodium monofluoroacetate) meat baits placed on soil in predator-proof cages remained toxic to dingoes, foxes and feral cats for at least 8 months regardless of whether they were protected from rain or not. Thus, untaken baits will remain a potential hazard to non-target species, particularly farm dogs, for a considerable period. However, when dingo-control programs were monitored (n = 3 stations), approximately 85% of meat baits were taken within 4 days. Dingo-control programs were undertaken on three stations by placing 1080 meat baits near water points (bores) with known dingo activity. Baiting was effective on two stations but not on the third. Where successful, dingo numbers were reduced by 50–70%. The failure on the third station was not due to the lack of bait-take as approximately 80% of these baits were taken within 4 days; it was probably caused by the presence of ephemeral water-bodies that could not be baited. However, this technique was effective in removing those dingoes that utilised the artificial water points, and hence were likely to be interacting with cattle. Such an outcome has benefits to both conservation and the pastoral industry, as problem dogs are removed without placing the long-term survival of dingoes at risk.

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