Pellet Group Counts Research Articles

Benefit of camera trapping for surveying the critically endangered Bawean deerAxis kuhlii(Temminck, 1836)

Despite being one of the rarest deer in the world, the critically endangered Bawean deer Axis kuhlii has received little conservation attention. Fauna monitoring is usually limited by lack of resource; therefore, the choice of a relevant methodology is fundamental to maximize the cost–benefit ratio. We compared the performance and cost of three direct and indirect methods to survey Bawean deer in protected areas of Bawean Island. Camera trapping provided a high number of records of Bawean deer (118 for 5500 camera days) and ascertained identifications of several other species. The number of photographs increased with the dry season. Transect sampling was time-consuming in the field for a poor result (two records for 19.200 h). Faecal pellet group count was more successful (80 pellet groups for 9.600 h of fieldwork). Camera traps are expensive to buy, but they lighten the field work and provide much data for further analyses.

Wildlife response to infrastructure: the problem with confounding factors

Understanding the effects of human infrastructure on wildlife is important for conservation and management and therefore widely studied. Challenges of many such studies are that they are often conducted after infrastructure establishment, when the exact consequence of the structure may be difficult to disentangle from other determinants of animal spatial use. To highlight these challenges, we use a case study of semi-domestic reindeer (Rangifer tarandus tarandus) spatial use within 5–6 km from an existing and a planned power line, using faecal pellet group counts in two areas in northern Norway. We found no relationship between pellet group density and distance to the existing power line, while the density of pellet groups decreased with increasing distance from the planned power line. Vegetation type was the main predictor of reindeer spatial use in the power line area, while elevation and vegetation cover accounted for the occurrence of reindeer in the area without power lines. Our results show that reindeer spatial use is a function of many aspects of the landscape, but not all of these are possible to control for. When this power line is built, what will an after-study of reindeer space use reveal? We underscore the importance of recording wildlife spatial use prior to, and after, infrastructure establishment for sound conclusions about animal response or lack thereof.

Impacts of introduced Rangifer on ecosystem processes of maritime tundra on subarctic islands

AbstractIntroductions of mammalian herbivores to remote islands without predators provide a natural experiment to ask how temporal and spatial variation in herbivory intensity alter feedbacks between plant and soil processes. We investigated ecosystem effects resulting from introductions of Rangifer tarandus (hereafter “Rangifer”) to native mammalian predator‐ and herbivore‐free islands in the Aleutian archipelago of Alaska. We hypothesized that the maritime tundra of these islands would experience either: (1) accelerated ecosystem processes mediated by positive feedbacks between increased graminoid production and rapid nitrogen cycling; or (2) decelerated processes mediated by herbivory that stimulated shrub domination and lowered soil fertility. We measured summer plant and soil properties across three islands representing a chronosequence of elapsed time post‐Rangifer introduction (Atka: ~100 yr; Adak: ~50; Kagalaska: ~0), with distinct stages of irruptive population dynamics of Rangifer nested within each island (Atka: irruption, K‐overshoot, decline, K‐re‐equilibration; Adak: irruption, K‐overshoot; Kagalaska: initial introduction). We also measured Rangifer spatial use within islands (indexed by pellet group counts) to determine how ecosystem processes responded to spatial variation in herbivory. Vegetation community response to herbivory varied with temporal and spatial scale. When comparing temporal effects using the island chronosequence, increased time since herbivore introduction led to more graminoids and fewer dwarf‐shrubs, lichens, and mosses. Slow‐growing Cladonia lichens that are highly preferred winter forage were decimated on both long‐term Rangifer‐occupied islands. In addition, linear relations between more concentrated Rangifer spatial use and reductions in graminoid and forb biomass within islands added spatial heterogeneity to long‐term patterns identified by the chronosequence. These results support, in part, the hypothesis that Rangifer population persistence on islands is facilitated by successful exploitation of graminoid biomass as winter forage after palatable lichens are decimated. However, the shift from shrubs to graminoids was expected to enhance rates of nitrogen cycling, yet rates of net N‐mineralization, pools, and soil δ15N declined markedly along the chronosequence and were weakly associated with spatial use within islands. Overall plant and soil patterns were disrupted but responded differently to intermediate (50 yr) and long‐term (100 yr) herbivory, and were correlated with distinct stages of irruptive population dynamics.

Estimating red deer abundance using the pellet-based distance sampling method

Many European agricultural landscapes have been abandoned facilitating the comeback of large ungulates. In Portugal, the increase in red deer numbers caused local conflicts with landowners reporting economic losses in forest and agricultural plantations. A great effort is needed to mitigate human-red deer conflicts through management strategies. Successful management strategies require reliable information on population trends. Here we propose an easy and readily applied method to estimate an increasing ungulate population. We estimated the red deer population density in a Mediterranean environment located in northeastern Portugal: Lombada National Hunting Area (LNHA) and Serra de Montesinho (SM), using pellet group counts coupled with distance sampling to account for pellet detectability. The estimated red deer density using a stratified detection function was 5.81 indd per 100 ha for LNHA and 1.34 indd per 100 ha for SM (95% CI: 3.65-9.25 and 0.74-2.42, respectively). For the entire area, the estimated density was 3.38 deer per 100 ha (95% CI: 2.18-5.24). Monitoring population trends is crucial to assess the impact of methods aimed at reducing the population size or impact and here we provided an example of a robust method that can be implemented to continuously monitor expanding populations.

Musk Deer (Moschus moschiferus) Population Density Based on Pellet Group Count Method in Sikhote-Alin

As a component of a complex program studying musk deer ecology in the Sikhote-Alin Biosphere Reserve, a survey of the musk deer population density, based on pellet group count method, was carried out at stationary posts from 2012 to 2014. The use of this method in the snowless season provides a means of surveying the most hard-to-reach areas of the musk deer habitat.

Classification of Vegetation Types in the Habitat of White-Tailed Deer in a Location of the Tehuacán-Cuicatlán Biosphere Reserve, Mexico

This paper classifies the vegetation types that comprise the habitat of the white-tailed deer Odocoileus virginianus at a location within the Tehuacan-Cuicatlan Biosphere Reserve (TCBR) in Mexico. The vegetation was sampled, identified, and mapped at 308 points distributed along 28 transects (each of 500 m in length). To determine the effect of the classified and mapped vegetation types on the white-tailed deer, we estimated population density using the PELLET procedure based on the pellet-group count method. The principal vegetation types at the study site are tropical dry forest (TDF, 63% of the area) dominated by tetecho ( Neobuxbaumia tetezo), uña de gato ( Mimosa spp.) and mulato ( Bursera spp.), and crassicaule scrub dominated by mantecoso ( Parkinsonia praecox). The TDF can be sub-classified into four spatially different clusters (vegetation types) depending on the dominance of these species. The white-tailed deer population density varied significantly depending on vegetation type. Our results contribute to the ecological knowledge of the white-tailed deer in tropical habitats and are of value for the implementation of effective conservation and management.

Browsing and damage inflicted by moose in young Scots pine stands subjected to high-stump precommercial thinning

In Fennoscandia, young stands of Scots pine (Pinus sylvestris L.) are intensively used by moose (Alces alces L.) during winter. We studied whether forage amounts on high-cut pines in high-stump commercial thinning influenced browsing intensity and damage incidence on retained (i.e. uncut) pine stems. High-cut pines were browsed, but to a lesser extent than retained pines. At a scale corresponding to individual feeding sites (≈40 m2), browsing intensity on retained pines was not influenced by the amount of forage on high-cut pines but was positively related to moose pellet group counts. The incidence of lower-height damage (stem breakage and bark stripping) was positively related to the amount of forage on high-cut pines, whereas higher damage (leader shoot browsing) was not. Overall browsing damage incidence on retained pines was positively related to the density of deciduous trees and negatively related to the amount of forage on retained pines. Our results suggest that although high-stump thinning supplies additional food resources for moose, larger amounts of forage on high-cut pines may increase the risk for bark stripping and stem breakage on retained trees. Further research is needed at larger spatial scales to assess the feasibility of high-stump thinning as a damage mitigation measure.

Country, cover or protection: what shapes the distribution of red deer and roe deer in the Bohemian Forest Ecosystem?

The Bohemian Forest Ecosystem encompasses various wildlife management systems. Two large, contiguous national parks (one in Germany and one in the Czech Republic) form the centre of the area, are surrounded by private hunting grounds, and hunting regulations in each country differ. Here we aimed at unravelling the influence of management-related and environmental factors on the distribution of red deer (Cervus elaphus) and roe deer (Capreolus capreolus) in this ecosystem. We used the standing crop method based on counts of pellet groups, with point counts every 100 m along 218 randomly distributed transects. Our analysis, which accounted for overdispersion as well as zero inflation and spatial autocorrelation, corroborated the view that both human management and the physical and biological environment drive ungulate distribution in mountainous areas in Central Europe. In contrast to our expectations, protection by national parks was the least important variable for red deer and the third important out of four variables for roe deer; protection negatively influenced roe deer distribution in both parks and positively influenced red deer distribution in Germany. Country was the most influential variable for both red and roe deer, with higher counts of pellet groups in the Czech Republic than in Germany. Elevation, which indicates increasing environmental harshness, was the second most important variable for both species. Forest cover was the least important variable for roe deer and the third important variable for red deer; the relationship for roe deer was positive and linear, and optimal forest cover for red deer was about 70% within a 500 m radius. Our results have direct implications for the future conservation management of deer in protected areas in Central Europe and show in particular that large non-intervention zones may not cause agglomerations of deer that could lead to conflicts along the border of protected, mountainous areas.

The impact of red deer on liverwort-rich oceanic heath vegetation

Background: There is concern about increasing numbers of large herbivores including red deer (Cervus elaphus), but little is known about their impact on bryophytes.Aims: This study set out to determine the effect of different localised densities of red deer on the internationally important Northern Atlantic hepatic mat, characteristic of oceanic heath vegetation, at four locations in the Scottish Highlands where sheep have been absent for decades.Methods: Thirty 7 m × 7 m plots were randomly located in each study area. The standing crop dung pellet group count method was used to estimate red deer density. Species richness, diversity and cover of hepatic mat liverworts were obtained from 1 m × 1 m quadrats placed at random within the sample plots. Calluna vulgaris cover, ericoid height, rock cover, gradient and altitude were also recorded.Results: Model simplification in analysis of covariance revealed a consistent pattern of decreasing cover of hepatic mat and Calluna with increasing red deer density at all four study areas. Northern Atlantic hepatic mat cover, diversity and species richness were positively correlated with Calluna cover.Conclusions: The data suggest that Calluna cover is reduced (through trampling and browsing) at high local densities of red deer which has had cascading effects on the Northern Atlantic hepatic mat. Alternative explanations are discussed.

Red deer impacts on the montane Racomitrium lanuginosum moss-heath community in north-west Scotland

Background: The effect of sheep grazing on the internationally important moss-heath community of the British uplands has been well studied but less is known about the impact of red deer (Cervus elaphus).Aim: To compare the impact of different densities of red deer on bryophytes and lichens associated with moss-heath vegetation at Beinn Eighe National Nature Reserve (low deer density) and a traditional sporting estate at Letterewe (with higher deer density), Scotland.Methods: Suitable pairs of summit study sites were selected at random, and species cover data were collected from thirty 1-m2 quadrats at each location. The dung pellet group count method was used to estimate red deer usage. Generalised linear models were fitted to the data.Results: Mean graminoid cover was significantly higher in two of the Letterewe study sites compared with their Beinn Eighe counterparts. Bryophyte cover and height in general matched the pattern for Racomitrium lanuginosum in that they were not significantly different between any of the study site pairings.Conclusions: Despite differences in mean deer density between the Beinn Eighe and Letterewe properties as a whole, red deer numbers actually using the exposed summit moss-heath vegetation were estimated to be very low. Therefore, bryophyte cover within the Letterewe summit study sites was not significantly different from that at Beinn Eighe.

Persistence of Carex bigelowii–Racomitrium lanuginosum moss heath under sheep grazing in the Grampian Mountains, Scotland

Carex bigelowii–Racomitrium lanuginosum moss heath has been monitored on the summit of Glas Maol, Grampian Mountains, Scotland since 1990 to assess the impact of herbivores and snow-lie. This vegetation community has high conservation value in Britain, being near-natural and the habitat of some rare arctic-alpine birds. In recent decades, it has decreased in extent in British uplands, and changed in composition due to declining Racomitrium cover, with the main drivers believed to be heavy grazing and nitrogen deposition. Permanent plots were established for the monitoring, laid out at fixed distances from a ski corridor built in 1986. Sheep grazing was assessed by pellet-group counts, and botanical composition by point-quadrat analysis. Monitoring was in summer annually between 1990 and 1996, but less frequently since. The moss heath was found to retain its main characteristics from 1990 to 2008/09, with Carex bigelowii Torr. ex Schwein dominant and Racomitrium lanuginosum (Hedw.) Brid. having much cover. There was a small but significant increase in grasses, and lichens declined, but the community remained species-poor. Some ground experienced increased grazing pressure and suffered a temporary decline of Racomitrium, but recovery followed despite continuing substantial grazing. The species experiencing greatest change was Dicranum fuscescens Turner, which first increased but later lost most of its cover; its relationships to Racomitrium lanuginosum are discussed.

Managing landscapes for multiple objectives: alternative forage can reduce the conflict between deer and forestry

Deer (Cervidae) cause considerable damage to forest plantations, crops, and protected habitats. The most common response to this damage is to implement strategies to lower population densities. However, lowering deer density may not always be desirable from hunting, recreational, or conservation perspectives. Therefore, knowledge is needed about additional factors beyond deer density that affect damage levels, and management actions that consider competing management goals. We studied the relationships between levels of bark‐stripping by red deer (Cervus elaphus) on Norway spruce (Picea abies) and (1) relative deer density indices (pellet group count and deer harvest data), (2) availability of alternative natural forage (cover of forage species) and (3) proportion forest in the landscape, both at a forest stand scale and at a landscape scale. Extensive variation in damage level was evident between the six study areas. On a stand scale, the proportion of spruce damaged was positively related to pellet group density, indicating the importance of local deer usage of stands. In addition, available alternative forage in the field layer within spruce stands and proportion forest surrounding stands was negatively related to damage level. On the landscape scale, damage level was negatively related to availability of forage in the field and shrub layers and proportion forest, but was not related to any of the relative deer density indices. Increasing alternative forage may thus decrease damage and thereby reduce conflicts. Additionally, the proportion of forest in the landscape affects damage levels and should thus be considered in landscape planning and when forecasting damage risk. The relationship between local deer usage of stands and damage level suggests that future studies should try to separate the effects of local deer usage and deer density.

Spatial and temporal habitat use and selection by red deer: The use of direct and indirect methods

Given the importance of red deer Cervus elaphus for hunting and conservation purposes, understanding the interactions between this species and its habitats in the Mediterranean region is a crucial step for the sustainable management of this species. Aiming to compare pellet group counts and direct observations methods to study the habitat use and selection by red deer, the results obtained by both methods were compared, and their advantages and disadvantages were discussed. To understand the temporal patterns of habitat use and selection, the survey was conducted at three different seasons, birth period, rut season and winter. The habitat use and selection were studied in relation to land cover, watercourse, roads, ecotone zones and other topographic features (altitude, slope and aspect), using generalized linear models and selection ratios. The similarity of the results provided by pellet group counts and direct observations indicate that both methods may constitute useful tools to study the habitat use and selection by red deer. Globally, red deer seemed to select habitats that provide simultaneously food and some cover, as shown by its preference for shrublands, independently of the sampling season. The positive selection of ecotone zones embodies the need for open spaces. Males and females showed a similar use of shrubland, but selected patches with different characteristics therein. The spatial and temporal patterns exhibited by our results suggest that red deer balance their habitat requirements in respect to each phase of their reproductive cycle. Pellet group counts and direct observations seem to be useful methods to analyze habitat use and selection, and may provide helpful knowledge to the management and conservation of red deer.

Seasonal Habitat Use of Persian Gazelles (Gazella subgutturosa subgutturosa) Based on Vegetation Parameters at Golestan National Park, Iran

Effective management and conservation of wildlife populations and their habitats depend on understanding and predicting species-habitat interaction. The distribution of Persian gazelles, which is related to habitat structure and dispersal of food resources, has been studied by clearance transect pellet group counts during different seasons. This study of habitat use was conducted by recording pellet groups along 20 permanent 3 m × 210 m transects in five vegetation types in the steppe habitat of Golestan National Park. Pellet groups were counted and cleared every two months over one year. Habitat use differed between seasons and vegetation types. Types I and II which featured diversified plant species, higher forage quality, and were adjacent to agricultural fields were used the most in all seasons and especially in fall and winter. Vegetation types III and IV with higher forage production, canopy cover, and vegetation density showed the lowest rate of use among all seasons. This could be due to the high protein content forage favoured by gazelles. The minimal model using multiple regression analysis showed a number of plant species were the indicative variable in gazelle habitats during each season. Positive relationship was detected between pellet group density and canopy cover of annual forbs and grasses in spring, with Aellenia sp in summer, and with Salsola rigida in fall and winter. This indicated higher use of types I and II throughout the year. The pellet group density of gazelles was negatively correlated with canopy cover of Stipa barbata and Poa bulbosa in all seasons, which indicated lower use of vegetation types III and IV.

An assessment of the applicability of dung count to estimate the wild boar population density in a forest environment

Wild boar is a native species in the fauna of the Czech Republic. It is becoming a problematic game species both in the Czech Republic and in other European countries due to its harmful impacts. So far no suitable method of its sustainable management has been devised. Yet, a correct abundance estimate is essential for proper management, field crop damage prevention and proper hunting planning. This paper employed faecal pellet group count to estimate the wild boar density in a forest environment. The research was conducted in a study area covering 12.83 km<sup>2</sup>, which is surrounded by farmland. The count was done under ideal conditions in early spring, after snow had melted. The study area was organised into several differing environments in which different dung densities were expected. The presence of feeding sites, where wild boars concentrated, was taken into account. The conducted count confirmed differences in the utilization of different habitats within the study area. The resulting wild boar abundance was estimated at 64.3 (± 8.9; 95% CI) indd·km<sup>–2</sup>.    

Densidad poblacional y caracterización de hábitat del venado cola blanca en un bosque templado de Oaxaca, México.

Se evaluó la densidad poblacional y se caracterizó el hábitat del venado cola blanca Odocoileus virginianus en un bosque templado de Santa María Yavesía, Sierra Norte de Oaxaca. Se realizaron dos muestreos temporales en 13 sitios pertenecientes a cinco asociaciones vegetales con el método de conteos de grupos fecales. Se calculó la densidad poblacional con el modelo de Eberhardt & Van Etten (1956) usando dos tasas de defecación. Se registró la presencia de venados sólo en el bosque de coníferas y el bosque de pino-encino cerrado. Las densidades promedio encontradas entre marzo a julio de 2008 fueron de 1.30 ± 3.04 individuos/km2 y de 0.49 ± 1.14 individuos/km2. Se midieron 13 variables del hábitat del venado cola blanca (vegetación y atributos físicos). Los sitios en el bosque de coníferas están a mayor altitud, son más fríos y húmedos, tienen más árboles grandes y un estrato arbustivo abierto. Las densidades poblacionales encontradas en el presente estudio fueron bajas, comparadas con las encontradas en otros estudios realizados con el método de conteo de grupos fecales en el país. Se proponen recomendaciones de manejo para los venados cola blanca de Santa María Yavesía.

How dear are deer volunteers: the efficiency of monitoring deer using teams of volunteers to conduct pellet group counts

AbstractDeer populations are increasing throughout the northern hemisphere, and unregulated numbers can jeopardize biodiversity and the economy. These populations are difficult to monitor using visual counts. Estimating densities from surveys of faecal pellets is reliable but time-consuming and thus, if carried out by professionals, expensive. Utilizing volunteers has clear advantages. Based on research from the UK (6 years) and Nova Scotia, Canada (4 years), we investigated the methodological refinements and training required to achieve reliable data when using volunteers. For safety reasons volunteers worked in teams of 5–10 (n = 611) under supervision of scientists. We compared faecal accumulation rate and faecal standing crop surveys using 10 × 10 m quadrats. Both methods produced similar estimates of density, but because of significant time savings and greater volunteer enjoyment we favour faecal standing crop over faecal accumulation rate surveys. Volunteer teams surveyed quadrats significantly faster than a single professional but needed significantly longer to reach and stake out new quadrats. On average, teams found 68% of all droppings. Performance of individuals was affected by training, gender, and willingness and aptitude to survey. After five quadrats men scored significantly higher than women but this difference was reduced after 20 quadrats. Age did not affect performance but willingness and aptitude correlated with ability to find and identify droppings. We conclude that volunteers can monitor deer effectively but that techniques should be modified. The provision of context, training, supervision and verification by a professional are essential. Because of the drain on scientists’ time, cost-effective volunteer deployment is a question of scale.

Ungulate-adapted forest management: effects of slash treatment at harvest on forage availability and use

Forest management strongly influences the interactions between ungulates and their food resources. Different ungulate-adapted measures have been proposed in forestry to improve forage availability or to reduce browsing damage. However, the potential and feasibility of such measures are inadequately known. We studied the effects of harvest timing and slash treatment in final felling and commercial thinning on the availability of Scots pine Pinus sylvestris forage and its use by ungulates during winter in the Swedish boreal forests. Pellet group counts showed that moose (Alces alces) was the dominating species using the post-harvest stands. Under conventional slash treatment, final felling stands held on average 226 kg pine forage ha−1 after harvesting and commercial thinning stands 137 kg ha−1. Ungulate-adapted slash treatment increased the available forage biomass by 20 %, but had no significant effect on consumption of forage by ungulates. Time since harvest had the strongest effect on forage consumption; for example, under conventional slash treatment, there was a tenfold increase in consumption (3 vs. 33 kg ha−1) following final felling as exposure time increased from 2–3 to 4–5 months. Consumption was higher in thinned stands than in final felling stands for the first 3 months but not later. To increase ungulate use of the forage made available at harvest, pine-dominated stands should be harvested in the late autumn or early in the winter.

Factors influencing red deer occurrence at the southern edge of their range: A Mediterranean ecosystem

The red deer is in the Iberian Peninsula at the southwestern edge of its European range and although widespread, red deer ecology in Portugal remains poorly understood. By using pellet group counts, we investigate how habitat structure, vegetation composition and human disturbance affect red deer occurrence. Red deer distribution was positively associated with areas with high density of heather, Leguminosae plants and patches with high cover of shrubs, ground cover and tree cover. Red deer occupied areas further away from roads and from villages. Red deer distribution was negatively associated with agricultural fields and areas with high canopy cover.In the perspective of the current climatic changes, continue research on red deer in these so-called edge populations represents an opportunity to assess the ecological responses within an evolutionary perspective and to provide important conservation suggestions for other countries located on the edge of its distribution range. The present results have implications for the conservation of red deer, emphasizing the need for wide range ecological studies. Red deer variation seems to be related to local factors rather than proximity to the edge of its range.

Estimation of deer population dynamics using a bayesian state-space model with multiple abundance indices

Deer population control is important in wildlife management, because overabundance of deer is a problem worldwide. For practical deer population control, deer population dynamics and the factors that influence them need to be evaluated in low-cost and time-efficient ways. However, in traditional methods of estimation, such as cohort analysis, large numbers of deer need to be caught for many years, and the ages of the deer must be determined. We estimated deer population dynamics by using a Bayesian state-space model with multiple deer abundance indices (seen deer per unit effort, pellet group count, and block count) and numbers of deer hunted and culled in Yamanashi Prefecture, central Japan. In the state process of our state-space model, latent deer abundance at year t in location m (Dt,m), with m being each cell of a grid mesh covering Yamanashi Prefecture, was assumed to decrease annually through hunting and culling, to increase with the population growth rate of each mesh (rm; which was determined from the percentages of forest, evergreen forest, and artificial grassland), and to fluctuate stochastically. In the observation process, Dt,m was assumed to be correlated with the deer abundance indices and a Gaussian white noise in the deer abundance indices. The estimated Dt,m was correlated with each deer abundance index, but the correlation coefficient was the greatest for pellet group density. The percentage of hunted and culled deer needed to reach 30% to reduce the annual growth rate (Dt,m/Dt−1,m). Increasing the percentage of artificial grassland increased rm. Our results showed that 1) deer abundance could be estimated by using only deer abundance indices in addition to population growth rate and the percentage of hunted and culled deer; and 2) preventing the intrusion of deer onto artificial grassland and intensive culling on artificial grassland were important to decrease deer abundance. © 2013 The Wildlife Society.