Medium and large mammals in a Cerrado fragment in Southeast Goiás, Brazil: inventory and immediate effects of habitat reduction on species richness and composition

Abstract: The reduction and fragmentation of remnant vegetation habitats has been one of the main threats to Cerrado biodiversity. The aim of the present study is to make an inventory of medium and large mammal species in a Cerrado remnant and to assess deforestation influence on part of this fragment on the richness and composition of mammal species. The study was conducted in a Cerrado fragment in southeast Goias State, Ipameri County. Data were collected during three different periods (P1, January-June, 2014; P2, December, 2016 - June, 2017; P3, July-December, 2017) through direct (visual, vocal and camera-trap records) and indirect methods (foot prints, animal burrows and other traces) in order to register the mammal species. Jackknife 1 estimator was used to estimate species richness during each of the three sampled periods and for the complete collection period; species similarity between periods was assessed through the Jaccard's Index of Similarity (Cj). Species richness between periods was performed through inference by overlapping confidence intervals (CI). Twenty-nine species were recorded during the assessed period, five of them were listed as endangered in Brazil. There was no significant change in species richness between the assessed periods: species richness of 25 species was observed in Period 1 (P1), the richness of 32 species was estimated (CI = 4.58); 23 species were recorded in Period 2 (P2), and the richness of 30 species was estimated (CI = 4.39), the richness of 23 species was observed in Period 3 (P3) and the richness of 28 species was estimated (CI = 4.70). Similarity in species composition between the assessed periods recorded Cj = 0.71 (71%) between P1 and P2, Cj = 0.66 (66%) between P1 and P3, and Cj = 0.77 between P2 and P3. Fragment deforestation did not influence the richness and composition of medium and large mammal species (within a period of 2~3 years) when the three periods were compared; however, the absence of changes in the community can be the result of time-lag, therefore, we cannot put aside the likelihood of mid and long-term effects.

摘要：残余植被生境的缩减与破碎化，是塞拉多（Cerrado）生物多样性面临的主要威胁之一。本研究旨在对一处塞拉多残余生境中的中大型哺乳动物物种开展本底调查，并评估该片段部分区域的森林砍伐对哺乳动物物种丰富度与群落组成的影响。本研究于巴西戈亚斯州东南部伊帕梅里县的一处塞拉多生境片段中开展。数据采集工作于三个不同时段（P1：2014年1月—6月；P2：2016年12月—2017年6月；P3：2017年7月—12月）完成，通过直接调查法（目视记录、鸣声记录与红外相机诱捕（camera-trap）记录）与间接调查法（足迹、动物洞穴及其他痕迹）记录区域内的哺乳动物物种。本研究采用刀切法1（Jackknife 1）估计三个采样时段及全采样周期的物种丰富度；通过雅卡尔相似性指数（Jaccard's Index of Similarity, Cj）评估时段间的物种组成相似性；借助置信区间（CI）重叠法开展时段间物种丰富度的统计推断。本研究在评估周期内共记录到29种哺乳动物，其中5种被列入巴西濒危物种名录。各评估时段的物种丰富度无显著变化：P1时段记录25种，估计丰富度为32种（置信区间=4.58）；P2时段记录23种，估计丰富度为30种（置信区间=4.39）；P3时段记录23种，估计丰富度为28种（置信区间=4.70）。各时段间的物种组成相似性分别为：P1与P2间Cj=0.71（71%），P1与P3间Cj=0.66（66%），P2与P3间Cj=0.77。对比三个时段后发现，在2~3年的观测周期内，该生境片段的森林砍伐未对中大型哺乳动物的物种丰富度与群落组成产生显著影响；但群落结构未发生变化可能是时间滞后效应导致的，因此不能排除中长期影响的可能性。