Examining the ecological complexities of blackfoot paua demography and habitat requirements in the scope of marine reserve protection

<p>A critical question for ecologists and fisheries managers is what drives the demographic processes that dictate the abundance and size structure of ecologically and commercially important species. Marine Reserves (MRs) provide an opportunity to examine species in the absence of human disturbance (i.e. no fishing) and to investigate how habitat type, quantity and condition contribute to yield large individuals and dense aggregations that are typical of a more natural state. However, an improved understanding of the efficacy of marine reserves requires a robust examination of habitats inside and outside reserves to distinguish any reserve effect from a potential confounding habitat effect. Abalone are a valuable nearshore fishery in many parts of the world and many stocks have been overexploited to the point of collapse. Countries striving to rebuild their abalone stocks are utilizing MRs to support viable populations and focusing on habitat requirements that produce large aggregations and individuals. The abalone commonly referred to as the blackfoot paua (Haliotis iris) is a culturally and ecologically important New Zealand (NZ) species and is the focus of customary, recreational and commercial fisheries. However, the demography and growth rates of paua populations are highly variable, with pockets of “stunted” populations occurring throughout NZ. Density-dependent processes, differential juvenile success, variable habitat quality and fishing pressure have all been suggested to influence the fitness of individuals and the demography of paua populations. My research utilizes MRs to control for fishing activity and thereby to investigate ecological patterns and the effects of habitat on paua abundance and size variability. The main objectives of this thesis were to quantify the response of paua to MR status, distinguish habitat effect from a reserve effect and understand the contribution of habitat variables on demography and growth. Research was conducted within and surrounding five MRs in central NZ. The habitats in and outside MRs were not significantly different in physical and biogenic characteristics, but paua occurred in significantly greater densities and were significantly larger within four MRs compared with outside, illustrating that marine reserves do afford protection for paua. Paua within MRs were significantly more dense and larger in areas of relatively higher wave exposure and dense macroalgal cover. Despite protection, paua were found to be undersized or “stunted” at Long Island and Horoirangi MRs. I conducted surveys to evaluate the effect of density and the contribution of habitat variables on paua size at two spatial scales across environmental gradients. To further test the hypothesis that habitat effects growth a 12 month translocation experiment was conducted at Long Island MR. The surveys revealed that environmental gradients exist at small and large scales and explained how paua size varied along these gradients. The habitat variables which supported larger size individuals were consistent across both locations, where paua were significantly larger in areas that were exposed with high algal cover than those at sheltered areas with low algal cover. This result was further confirmed by the translocation experiment which revealed that paua translocated from a stunted environment to a normal environment grew significantly more than conspecifics placed at the stunted environment. To further explore the response of paua to protection and see if patterns were consistent across bioregions in areas with “normal” size paua I conducted research at the Taputeranga MR on the Wellington South Coast to evaluate juvenile and adult population densities and examine stage-specific habitat requirements. Juvenile paua were found in higher densities at fished sites in areas that were sheltered from wave exposure and dominated by cobbles and boulder fields. Adult paua were found in greater densities and were larger in size within the reserve than outside, which was the opposite finding to the baseline survey illustrating reserve effectiveness. Although within the reserve there were large aggregations and individual adults which may support population reproductive success, juvenile and adult population densities were not correlated. Results from this study indicate that marine reserve implementation does have an impact on adult populations but that habitat is more important for juvenile success. Although this thesis focused on paua within the scope of protection, MRs are placed in NZ to protect a suite of species. To thoroughly investigate habitats I conducted a rigorous inside-outside habitat analysis utilizing multibeam bathymetric data and video footage from drop camera surveys at Taputeranga MR. Habitat maps produced by NIWA were utilized to plan drop camera sampling locations and 278 drops were conducted across 8 sites associated with TMR. Analysis revealed that habitats within fished and reserve sites were comparable in physical and biogenic habitat quantities, although the reserve had greater topographic relief. However, when examining only a subsample of fished sites there were pronounced habitat differences between in and outside the reserve, where the western fished sites have significantly more rocky reef with greater algal cover than the reserve and eastern sites. These results illustrate the need for quantification of habitat when siting fished (control) areas and conducting inside versus outside reserve comparisons. This research has determined that MRs do afford protection for paua in central NZ. The differentiation between habitat and reserve effects that I have identified has direct relevance to current and future MRs in NZ and highlights the need for studies to examine habitat effect in MR spatial planning at a global level. Furthermore, this research highlights the importance of considering stage-specific habitat requirements when designing the spatial arrangement of MRs by protecting juvenile habitat as well as adults to increase chances of recovery. These abalone-habitat associations, showing the importance of exposure and macroalgal cover for growth, can be used to assist in management decisions within NZ such as considerations for siting management areas and potential translocations and are directly applicable to abalone conservation, management concerns and recovery efforts across the world.</p>

Examining the ecological complexities of blackfoot paua demography and habitat requirements in the scope of marine reserve protection

<p>A critical question for ecologists and fisheries managers is what drives the demographic processes that dictate the abundance and size structure of ecologically and commercially important species. Marine Reserves (MRs) provide an opportunity to examine species in the absence of human disturbance (i.e. no fishing) and to investigate how habitat type, quantity and condition contribute to yield large individuals and dense aggregations that are typical of a more natural state. However, an improved understanding of the efficacy of marine reserves requires a robust examination of habitats inside and outside reserves to distinguish any reserve effect from a potential confounding habitat effect. Abalone are a valuable nearshore fishery in many parts of the world and many stocks have been overexploited to the point of collapse. Countries striving to rebuild their abalone stocks are utilizing MRs to support viable populations and focusing on habitat requirements that produce large aggregations and individuals. The abalone commonly referred to as the blackfoot paua (Haliotis iris) is a culturally and ecologically important New Zealand (NZ) species and is the focus of customary, recreational and commercial fisheries. However, the demography and growth rates of paua populations are highly variable, with pockets of “stunted” populations occurring throughout NZ. Density-dependent processes, differential juvenile success, variable habitat quality and fishing pressure have all been suggested to influence the fitness of individuals and the demography of paua populations. My research utilizes MRs to control for fishing activity and thereby to investigate ecological patterns and the effects of habitat on paua abundance and size variability. The main objectives of this thesis were to quantify the response of paua to MR status, distinguish habitat effect from a reserve effect and understand the contribution of habitat variables on demography and growth. Research was conducted within and surrounding five MRs in central NZ. The habitats in and outside MRs were not significantly different in physical and biogenic characteristics, but paua occurred in significantly greater densities and were significantly larger within four MRs compared with outside, illustrating that marine reserves do afford protection for paua. Paua within MRs were significantly more dense and larger in areas of relatively higher wave exposure and dense macroalgal cover. Despite protection, paua were found to be undersized or “stunted” at Long Island and Horoirangi MRs. I conducted surveys to evaluate the effect of density and the contribution of habitat variables on paua size at two spatial scales across environmental gradients. To further test the hypothesis that habitat effects growth a 12 month translocation experiment was conducted at Long Island MR. The surveys revealed that environmental gradients exist at small and large scales and explained how paua size varied along these gradients. The habitat variables which supported larger size individuals were consistent across both locations, where paua were significantly larger in areas that were exposed with high algal cover than those at sheltered areas with low algal cover. This result was further confirmed by the translocation experiment which revealed that paua translocated from a stunted environment to a normal environment grew significantly more than conspecifics placed at the stunted environment. To further explore the response of paua to protection and see if patterns were consistent across bioregions in areas with “normal” size paua I conducted research at the Taputeranga MR on the Wellington South Coast to evaluate juvenile and adult population densities and examine stage-specific habitat requirements. Juvenile paua were found in higher densities at fished sites in areas that were sheltered from wave exposure and dominated by cobbles and boulder fields. Adult paua were found in greater densities and were larger in size within the reserve than outside, which was the opposite finding to the baseline survey illustrating reserve effectiveness. Although within the reserve there were large aggregations and individual adults which may support population reproductive success, juvenile and adult population densities were not correlated. Results from this study indicate that marine reserve implementation does have an impact on adult populations but that habitat is more important for juvenile success. Although this thesis focused on paua within the scope of protection, MRs are placed in NZ to protect a suite of species. To thoroughly investigate habitats I conducted a rigorous inside-outside habitat analysis utilizing multibeam bathymetric data and video footage from drop camera surveys at Taputeranga MR. Habitat maps produced by NIWA were utilized to plan drop camera sampling locations and 278 drops were conducted across 8 sites associated with TMR. Analysis revealed that habitats within fished and reserve sites were comparable in physical and biogenic habitat quantities, although the reserve had greater topographic relief. However, when examining only a subsample of fished sites there were pronounced habitat differences between in and outside the reserve, where the western fished sites have significantly more rocky reef with greater algal cover than the reserve and eastern sites. These results illustrate the need for quantification of habitat when siting fished (control) areas and conducting inside versus outside reserve comparisons. This research has determined that MRs do afford protection for paua in central NZ. The differentiation between habitat and reserve effects that I have identified has direct relevance to current and future MRs in NZ and highlights the need for studies to examine habitat effect in MR spatial planning at a global level. Furthermore, this research highlights the importance of considering stage-specific habitat requirements when designing the spatial arrangement of MRs by protecting juvenile habitat as well as adults to increase chances of recovery. These abalone-habitat associations, showing the importance of exposure and macroalgal cover for growth, can be used to assist in management decisions within NZ such as considerations for siting management areas and potential translocations and are directly applicable to abalone conservation, management concerns and recovery efforts across the world.</p>

REALIZED ECOLOGICAL NICHE OF THE MEXICAN SPOTTED OWL (Strix occidentalis lucida) IN MEXICO

Objective: To characterize the realized niche of the Mexican spotted owl (Strix occidentalis lucida) and compare the environmental values it uses within the Mexican physiographic provinces.Design/methodology/approach: The environmental temperature variables (n =7), precipitation (n = 7) and elevation (n = 1) were extracted from 79 unique occurrences sites of S. o. lucida. These values were grouped by physiographic provinces: Sierra Madre Occidental (n = 59), Sierra Madre Oriental (n = 13) and Transversal Neovolcanic Belt (n = 6). The climate and elevation of these sites were described and compared via non-parametric Kruskal-Wallis and Bonferroni-Dunn tests (P ? 0.05).Results: The presences of the spotted owls were both, dispersed and focallydistributed, over the geographic space in Mexico. The temperature and elevation variables have similar characteristics in the assessed physiographic provinces. To be noted, the precipitation variables showed significant differences among sites.Limitations on study/implications: This study describes the environmental characteristics of the realized niche of the Mexican spotted owl; however, it isnecessary to investigate other habitat variables at a smaller scale. Findings/conclusions: The temperature and elevation environmentalcharacteristics of the ecological niche of the Mexican spotted owl was similar between physiographic provinces.

MÉTODOS QUANTITATIVOS PARA MENSURAR A DIVERSIDADE TAXONÔMICA EM PEIXES DE RIACHO

Species diversity is defined as the variety of species and their relative abundances, and can be decomposed in local (alpha), regional (gamma) and between-communities (beta) diversity. For decades, studies with Brazilian stream fish focused on the relationship between local environmental variables and diversity patterns. However, dispersal gained notoriety for being important to the organization of communities. Besides, large scale variables are increasingly being perceived as good predictors of diversity, complementing the role of habitat variables. We present here a brief review of the methods to obtain alpha and beta taxonomic diversity, considerations regarding their predictors, and their main analysis.

Nearshore Fish Species Richness and Species–Habitat Associations in the St. Clair–Detroit River System

Shallow water riparian zones of large rivers provide important habitat for fishes, but anthropogenic influences have reduced the availability and quality of these habitats. In the St. Clair–Detroit River System, a Laurentian Great Lakes connecting channel, losses of riparian habitat contributed to impairment of fish populations and their habitats. We conducted a seine survey annually from 2013 to 2019 at ten sites in the St. Clair and Detroit rivers to assess riparian fish communities, and to identify habitat attributes associated with fish species richness and catches of common species. We captured a total of 38,451 fish representing 60 species, with emerald shiner Notropis atherinoides composing the largest portion of the catch. We used an information-theoretic approach to assess the associations between species richness and catches of 33 species with habitat variables (substrate, shoreline vegetation types, and aquatic macrophyte richness). Sand, cobble, and algal substrates and shoreline vegetation were important predictors of species richness based on a multimodel inference approach. However, habitat associations of individual species varied. This work identified manageable habitat variables associated with species richness, while identifying potential tradeoffs for individual species. Further, this work provides baselines for development and evaluation of fish community and shoreline habitat restoration goals.

Approaching wildlife with drones: using scientific literature to identify factors to consider for minimising disturbance

ABSTRACT Drones are a modern alternative to manned aircraft for aerial surveys, however approaching wildlife with drones may still cause disturbance. Understanding the factors influencing animal responses to drone flights is fundamental for informing guidance on lowest-impact flight practices. We reviewed scientific literature on drone flights conducted to approach wildlife and collated and quantified references to factors that should be considered in the development of guidelines and policies. The most referenced controllable factors were approach distance, noise emissions and airspeed. Other frequently referenced controllable factors included drone type, take-off distance, flight pattern, pilot experience and competence, whether consecutive flights were conducted and flight duration. The most referenced environmental factors were animal taxa, biological state of animals and ambient noise, followed by whether conspecifics are present, weather variables, habitat variables, whether animals have received previous exposure to anthropogenic settings, animals’ behaviour prior to drone flights and whether predators are present. Policies and protocols that address these factors have an increased probability of minimising disturbance of drone flights. The variability in animal responses across different taxa, different ways drone flights are performed and the different circumstances they are deployed in highlights the need for taxa-specific protocols that also account for geographical and biological variations.

Urbanization, Bird Species Richness And Abundance Within Ibadan Metropolis, Nigeria

Urbanisation is considered as one of the most profound threat to wildlife, with habitat loss and fragmentation being predominant. This study assessed the impacts of urbanisation on richness, abundance of bird species within Ibadan metropolis, Nigeria. A uniform grid of 500 square meters was installed on the map of Ibadan Metropolis using QGIS to produce 499 grid points distributed across the five urban local governments. 100 grids were selected randomly, identified with mapinR software application and surveyed with 5 point counts within each gird, established at 200m interval to avoid double counting. Each point count was observed for 5 minutes using a pair of 8x42mm binoculars within a 50m radius. Habitat variables like number of buildings, trees, paved roads, communication masts were also recorded. A total number of 56 species of birds were observed at the end of the assessment, classified into 30 families. The test of statistics showed that there was no statistically significant difference in bird species richness between the Local Governments. The test of statistics showed that there was no statistically significant difference in bird species abundance between the local governments. The test of between-subjects effects revealed that there were no statistical significant effects when all the habitat variables were computed in the model on species richness. The number of paved roads and number of vehicles showed a significant effect on bird species abundance while others variables in the model did not exact statistically significant effects on bird species abundance. The study therefore concluded that habitat actions due to urbanisation have not affected the richness and abundance of birds species found in all the local governments. The only habitat variables that have currently exacted significant effect on species abundance within the metropolis are number of vehicles and paved roads.

The effect of different logging regimes on the ecomorphological structure of stream fish assemblages in the Brazilian Amazon

We evaluated the effects of changes in habitat structure resulting from conventional logging (CL) and reduced-impact logging (RIL) on the ecomorphological structure of stream fish assemblages in the eastern Brazilian Amazon, investigating (1) which habitat characteristics are influenced by different logging methods, (2) the differences in the ecomorphological structure of fish assemblages between two logging methods and undisturbed forest (UF), and (3) the relationships between ecomorphological traits of fish assemblages and habitat variables. We measured 13 habitat variables and characterized 11 ecomorphological traits of 55 fish species collected in 34 sampling sites (stream stretches) located in CL, RIL, and UF. In logged areas, the streams present a fine sediment increase and reduced vegetation cover, while in the UF a greater amount of natural shelter and more cover vegetation were observed. These environmental changes selected ecomorphological traits of stream fish assemblages, recording a greater relative width of the mouth in UF, higher ventral flattening index in RIL, or greater relative head length, and higher caudal peduncle compression index in CL. In this sense, we recommend that logging practices, including RIL, should be reviewed as a means of adopting better strategies to minimize human disturbances in streams.

Fish communities and associated habitat variables in the upper Subansiri River of Arunachal Pradesh, eastern Himalaya, India

Ecological information on the rivers of eastern Himalaya, specifically the state of Arunachal Pradesh is not studied well. The present study describes fish assemblage patterns and deriving relationships between local habitat variables in the upper reaches of Subansiri River, Arunachal Pradesh. This study was carried out during October to November 2014 and February to March 2015. A total of 26 fish species belonging to eight families were recorded, in which eight species are endemic to the eastern Himalayan region. Fish species richness varied from two to 18 species in the upper reaches of Subansiri River and high species diversity was recorded in Sigin Stream (H’=2.76). Based on the seven habitat variables (water velocity, depth, channel width, percentage of substrate composition, percentage of riparian vegetation, altitude, and water temperature) then streams were categorized into lower-order and higher-order streams using principal component analysis (PCA). The site-wise fish abundance data along with habitat variable information was then subjected to the canonical correspondence analysis (CCA) for testing the association of habitat variables on fish abundance. The CCA results revealed that the abundance of large-size barbs, Neolissochilus hexagonolepis, N. nigrovittatus, Schizothorax progastus, and S. richardsonii were strongly associated with high altitude, water velocity, rich dissolved oxygen, and good riparian vegetation. On the other hand, Channa gachua, Botia rostrata, Danio rerio, Devario aequipinnatus, and Garra nasuta showed strong association with warm water streams with more conductivity.